# Patent

## Title
Computer system and program product for controlling vibrations

## Abstract

The computer programmable system and program product include first program instructions for actively driving a first imbalance mass concentration rotor and a second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit periodic vibrations. The program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency. The system includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system.

## Background
CROSS REFERENCE
This application is a continuation of U.S. patent application Ser. No. 11/557,384, filed Nov. 7, 2006 now U.S. Pat. No. 7,722,322. This application claims the benefit of, and incorporates by reference, U.S. Provisional Patent Application No. 60/734,232 filed on Nov. 7, 2005. This application is a Continuation-in-Part (CIP) of, and claims the benefit of, and incorporates by reference, U.S. patent application Ser. No. 11/215,388 filed on Aug. 30, 2005 now U.S. Pat. No. 7,448,854, and which claims priority to U.S. Provisional Patent Application No. 60/605,470 filed on Aug. 30, 2004, and which this application claims the benefit of and incorporates by reference.


FIELD OF THE INVENTION
The invention relates to the field of computer program methods/systems for controlling vibrations, particularly for electronically controlling vibration control systems with imbalance rotors to inhibit vibrations. More particularly the invention relates to computer programs and control software for controlling rotating assembly vibrations, particularly computer program methods and control systems for controlling problematic rotating helicopter vibrations.
BACKGROUND OF THE INVENTION
Helicopter vibrations are particularly troublesome in that they can cause fatigue and wear on the equipment and occupants in the aircraft. In vehicles such as helicopters, vibrations are particularly problematic in that they can damage the actual structure and components that make up the vehicle in addition to the contents of the vehicle.
There is a need for a computer program system and computer instruction execution method of accurately and economically controlling rotating vehicle assembly vibrations. There is a need for a system and method of accurately controlling rotary wing vibrations in an efficient manner. There is a need for a method of controlling vibrations in a helicopter rotating hub assembly so that the vibrations are efficiently minimized. There is a need for a robust system of controlling vibrations with a vibration control system so that the vibrations are efficiently minimized. There is a need for a method/system for electronic control of problematic helicopter vibrations.
SUMMARY OF THE INVENTION
In an embodiment the invention includes a computer programmable media containing programmable software to control a rotating assembly vibration control system with a first imbalance mass concentration rotor and a second imbalance mass concentration rotor, for a rotating assembly having a periodic vibration while rotating at an operational rotation frequency. The computer programmable software includes first program instructions for rotating the first imbalance mass concentration rotor and the second imbalance mass concentration rotor at a whole number multiple vibration canceling rotation frequency greater than the rotating assembly operational rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a rotating net force vector to inhibit the periodic vibration. The computer programmable software includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a starting stopping rotation speed less than the whole number multiple vibration canceling rotation frequency.
In an embodiment the invention includes a computer program product for controlling a rotating vibration control system with a first imbalance mass concentration rotor and a second imbalance mass concentration rotor. The computer program product includes a computer readable medium. The computer program product includes first program instructions for driving the first imbalance mass concentration rotor and the second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a net force vector to inhibit a vibration. The computer program product includes second program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a transitioning rotation speed.
In an embodiment the invention includes a computer program product for controlling a rotating assembly vibration control system. The computer program product includes a computer readable medium and first program instructions to control a rotation of a first rotor and a rotation of a second rotor. The computer program product includes second program instructions to monitor a plurality of sensor signals. The computer program product includes third program instructions to control the rotation speed and phase of the first rotor and the rotation speed and phase of the second rotor to minimize a monitored vibration sensor signal.
In an embodiment the invention includes a rotating vibration control system for an assembly having an operational vibration. The vibration control system includes a first motor having a first rotor with a first imbalance mass concentration, with the first motor driving a rotation of the first rotor. The vibration control system includes a second motor having a second rotor with a second imbalance mass concentration, with the second motor driving a rotation of the second rotor. The vibration control system includes a first vibration sensor for producing a first vibration sensor signal. The vibration control system includes a second vibration sensor for producing a second vibration sensor signal. The vibration control system includes a first rotor rotational position sensor. The vibration control system includes a second rotor rotational position sensor. The vibration control system includes a motor control loop for controlling the rotation of the first rotor and the rotation of the second rotor. The vibration control system includes a vibration control loop for providing commands to the motor control loop to minimize the first vibration sensor signal and the second vibration sensor signal.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating hub mounted vibration control system for a helicopter rotary wing hub having a periodic vibration while rotating at a helicopter operational rotation frequency. The helicopter rotating hub mounted vibration control system includes an annular ring housing attachable to the helicopter rotary wing hub and rotating with the helicopter rotary wing hub at the helicopter operational rotation frequency. The annular ring housing is centered about the rotary wing hub axis of rotation and preferably has an electronics housing cavity subsystem. The housing preferably includes a first motor, most preferably a coaxial frameless AC ring motor. The first motor having a first rotor with a first imbalance mass. The housing preferably includes a second motor, most preferably a coaxial frameless AC ring motor. The second motor having a second rotor with a second imbalance mass. The electronics housing cavity subsystem contains an electronics control system which utilizes electronic inputs and outputs and electrically controls and drives the first motor and the second motor such that the first imbalance mass and the second imbalance mass are driven, preferably directly driven, at a vibration canceling rotation frequency preferably greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating vibration control system for a rotating wing hub assembly having a periodic vibration while rotating at an operational rotation frequency about an axis of rotation. The system includes a first motor with a first rotor with a first imbalance mass concentration. The system includes a second motor with a second rotor with a second imbalance mass concentration. The system includes an electronics control system which controls a speed and a phase of the first motor and the second motor such that the first imbalance mass concentration and the second imbalance mass concentration are driven at a vibration canceling rotation frequency wherein the periodic vibration is reduced.
In an embodiment the invention includes a method of controlling a periodic vibration of an assembly which rotates at an operational rotation frequency. The method includes providing an electronics housing cavity subsystem and a rotor housing cavity subsystem. The rotor cavity subsystem contains a first motor with a first rotor with a first imbalance rotor eccentric mass concentration. The rotor cavity subsystem contains a second motor having a second rotor with a second imbalance rotor eccentric mass concentration. The electronics housing cavity subsystem contains an electronics control system which controls the speed and phase of the first motor and the second motor. The method includes electromagnetically driving, preferably directly driving, the first rotor and the second rotor at a vibration canceling rotation frequency while controlling the rotational phase position of the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration in order to produce a net force vector to counteract disturbance forces that create periodic vibration. The electronic control system processes sensor inputs to determine the orientation and speed of the rotors, and calculates and modifies the speed and orientation of the rotors in order to cancel and balance out the unwanted vibrations.
In an embodiment the invention includes a method of controlling a periodic vibration. The method includes driving a first imbalance rotor and a second imbalance rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance rotor eccentric mass concentration and the rotational position of the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration.
In an embodiment the invention includes a computer programmable media containing programmable software to control a rotating assembly vibration control system with an at least first imbalance mass concentration rotor and an at least second imbalance mass concentration rotor, for a rotating assembly having a periodic vibration while rotating at an operational rotation frequency. The computer programmable software including first program instructions for driving the at least first imbalance mass concentration rotor rotation and the at least second imbalance mass concentration rotor rotation at a vibration canceling rotation frequency while controlling the rotational position of the at least first imbalance mass concentration and the at least second imbalance mass concentration to produce a rotating net force vector to inhibit the periodic vibration. The computer programmable software including second program instructions to opposingly orient the at least first imbalance mass concentration relative to the at least second imbalance mass concentration during a starting stopping rotation speed less than the vibration canceling rotation frequency.
It is to be understood that both the foregoing general description and the following detailed description are exemplary of the invention, and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate various embodiments of the invention, and together with the description serve to explain the principals and operation of the invention.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a software control system/method for controlling vibrations.
FIG. 2 shows a soft start stop software control system/method.
FIGS. 3A-B shows a soft start phase map.
FIG. 4 shows soft start experimental results of an implementation of a constant acceleration profile.
FIGS. 5A-E shows a simulated implementation of a soft start program instructions with a vibration control system.
FIG. 6 shows an ALE tracking bandpass filter software control system/method used to filter vibration input sensors.
FIG. 7 shows an influence coefficient algorithm with condition based stepping for software control of a vibration control system.
FIG. 8 shows a Fourier coefficient filter for a software control system/method used in a vibration control system.
FIGS. 9A-C shows an influence coefficient algorithm for software control of a vibration control system.
FIG. 10 shows an inner loop motor control for driving the rotation of vibration control system rotors.
FIG. 11 shows a rollover continuity logic for a software control system/method used in a vibration control system.
FIG. 12 shows a motor control compensator for a software control system/method used in a vibration control system.
FIG. 13 shows a motor control soft command system for control of a vibration control system.
FIGS. 14A-B illustrates commanded rotor positions just prior to a rotor motor failure and just after the rotor motor failure of a vibration control system.
FIG. 15 shows a C-code implementing reversion control for a fault mode control protocol of a vibration control system.
FIGS. 16A-C shows an experimental emulation of a one rotor motor failure of a vibration control system.
FIG. 17A-B show methods/systems for controlling helicopter vibrations.
FIG. 18A-B show a vibration control systems.
FIG. 19A-D show a vibration control systems.
FIG. 20A-D show methods/systems for controlling vibrations.
FIG. 21 shows a electronics control system for implementing program instructions to control vibrations.
FIG. 22 shows a vibration control systems.
FIG. 23 shows a method/system for controlling vibrations.
FIG. 24A-E show vibration control methods/systems.
FIG. 25A-H show vibration control systems for implementing program instructions to control vibrations.
FIG. 26A-C show vibration control methods/systems.



DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings.
In an embodiment the invention includes a vibration control system including an electronics control system that executes program instructions. The vibration control system 20 preferably includes an electronics control system 50 that executes program instructions, preferably such as shown in FIG. 1-16, to control problematic vibrations associated with rotating assemblies. Preferably an instruction execution system computer is integrated into the electronics control system 50 and provides a means for controlling the vibration control system 20 with operating instructions. Computer program instructions are preferably utilized with an electronics control instruction execution system computer to operate and control the vibration control system. Preferably the invention includes a computer programmable media and computer program products containing the vibration control system program instructions. The invention provides a computer program product for controlling the rotating assembly vibration control system 20. A preferred application of the vibration control system utilizing the computer programmable media in the electronics control system 50 is shown in FIG. 17-27. In a preferred embodiment the invention includes a rotary wing aircraft helicopter rotating hub mounted vibration control system 20 for a helicopter rotary wing hub 22 having a periodic vibration 24 while rotating at a helicopter operational rotation frequency 26. The helicopter rotating hub mounted vibration control system includes an annular ring housing 30 attachable to the helicopter rotary wing hub and rotating with the helicopter rotary wing hub at the helicopter operational rotation frequency. The annular ring housing preferably has an electronics housing cavity subsystem 32. The housing preferably includes a first motor 36, most preferably a coaxial frameless AC ring motor. The first motor having a first rotor 38 with a first imbalance mass 40. The housing preferably includes a second motor 42, most preferably a coaxial frameless AC ring motor. The second motor having a second rotor 44 with a second imbalance mass 46. The electronics housing cavity subsystem contains an electronics control system 50 which utilizes electronic inputs and outputs and electrically controls and drives the first motor and the second motor such that the first imbalance mass and the second imbalance mass are driven, preferably directly driven, at a vibration canceling rotation frequency 52 preferably greater than the helicopter operational rotation frequency 26 wherein the helicopter rotary wing hub periodic vibration 24 is reduced.
In an embodiment the invention includes the vibration control system 20 with electronics control system 50. The electronics control system 50 preferably includes the control execution computer, preferably with at least one instruction execution system computer that is integrated into the electronics control system and provides a means for controlling the vibration control system with operating instructions. Computer program instructions are preferably utilized with an electronics control instruction execution system computer to operate and control the vibration control system via the electronics control system 50. Preferably the invention includes a computer programmable media and computer program products containing the vibration control system program instructions for use in the electronics control system 50. The invention provides a computer program product for controlling the rotating assembly vibration control system. The computer program product comprises a computer readable or computer-usable medium, which provides program code for use by or in connection with a computer or any instruction execution system. For the purposes of this description, a computer-usable or computer readable medium can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device, preferably with the electronics control system 50 of the vibration control system 20. Preferably, the computer storage medium can be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Examples of a computer-readable medium include a semiconductor or solid state memory, magnetic tape, a readable computer diskette, a random access memory (RAM), a flash memory, a read-only memory (ROM), a rigid magnetic disk and an optical disk. Current examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD. Further, preferably, network medium can comprise of transmission devices on a network, such as, cables, routers, switches and/or network adapter cards.
In an embodiment the electronics control instruction execution system computer preferably is a programmable digital signal processor processing unit, most preferably such as a MPC555 DSP computer integrated with the electronics control system infrastructure 50. In a preferred embodiment the electronics control instruction execution system computer includes a high-speed microcontroller Central Processing Unit (CPU), such as the MPC555 32-bit CPU commercially available from Freescale Semiconductor, Inc. (www.freescale.com). In a preferred embodiment the electronics control instruction execution system computer is comprised of programmable processing units, most preferably such as field programmable gate arrays, computer logic devices, computer processors, digital signal processors, and memory devices integrated into the electronics control system 50 (such as shown in FIG. 21), preferably with duplicate redundant programmable processing units for backup redundancy. As shown in FIG. 21 the electronics control system 50 electronics control instruction execution system unit includes the integrated IM_0 with SCM_O and IM_1 with SCM_1, with the electronics control system 50 having duplicate redundancy on the left hand half with the IM_0 and SCM_O and on the right hand side half IM_1 and SCM_1. As shown in FIG. 25D1-25D8, the SCM_0 includes the VC33 Motor Drive Core DSP digital signal processor, VC33 Outer Loop Core DSP digital signal processor and the APA 750 FPGA field programmable gate array, and the IM_0 includes the APA 150 FPGA field programmable gate array. As shown in FIG. 25F1-25F8 the SCM_1 includes the VC33 Motor Drive Core DSP digital signal processor, VC33 Outer Loop Core DSP digital signal processor and the APA 750 FPGA field programmable gate array, and the IM_1 includes the APA 150 FPGA field programmable gate array. Preferably the instruction execution computer and control system includes computer architecture and related computer systems integrated in the vibration control system electronics infrastructure 50. It should be understood, that although not specifically shown, other hardware and software components (e.g. additional computer systems) could be included in the vibration control system electronics infrastructure 50. The vibration control system includes a CPU (hereinafter processing unit), memory, a bus, and input/output interfaces. Further, the vibration control system computer system communicates with external I/O devices/resources and storage systems. In general, the processing unit executes computer program instructions. Still further, it is understood that one or more additional components (e.g. system software, math co-processing unit, etc.) can be included in the computer system, including a storage system which can be any type of system capable of providing storage for information. Additional components, such as cache memory, communication systems, system software, etc., may be incorporated into the computer system.
In embodiments of the invention, several components of the control software are preferred. In an embodiment the control software components preferably include a Soft Start/Stop tachometer control, an Influence Coefficient Algorithm, and a wrapping phase motor control algorithm. FIG. 1 shows an embodiment of a layout of the control software structure. The vibration control system software effectively reduces vibrations. The vibration control system software performs under many different conditions including transient disturbance force conditions, transient speed conditions, transient phase conditions, and various combinations of transient conditions. The vibration control system 20, electronics control system infrastructure 50 and software demonstrates the ability to track these transient operational conditions extremely fast while maintaining stability. The vibration control system 20 and software demonstrates the ability to softly start and stop in a controlled manner without inducing any extra problematic vibration into the helicopter hub rotating machine assembly 22.
In an embodiment the software program instructions preferably interact with the physical vibration control system 20 through various electrical signals, for example such as follows:












Symbol
Description
Details







Vib X, Vib Y
Accelerometers (Input)
Preferably two vibration sensing




accelerometer sensors located on the




x and y (lateral) plane (FIG. 21




vibration sensor accelerometers 72.)


Tach
Tachometer (Input)
Preferably the Tach input is repeating




periodic pulse train generated from




the rotor shaft or the incoming AC




power as the helicopter rotating




assembly rotates. Incoming Tach is a




5 V differential 50% duty cycle pulse.




The pulse frequency (in Hz) is the




main rotor shaft frequency (in Hz)




multiplied by a ratio of integers. The




Tach input is preferably converted to




Tach_Theta and Tach_Hz.


R1_theta
Rotor encoder (rotor position
Preferably the R#_theta


R2_theta
sensor read heads)
includes three TTL signals denoted A,



outputs (Input)
B, and I: A and B are binary signals



(Mtr 1 Theta, Mtr 2 Theta)
each providing 588 rising edges per




revolution and phased in quadrature.




Signal I provides one rising edge per




revolution located at a known rotor




position with respect to the imbalance




mass concentration.


Mtr_1_Command
Current Commands
The current command outputs are


Mtr_2_Command
(Output)
analog signals between +/−10 V.




Mtr_1_Command is inputted into the




System Hardware as Cmd 1.




Mtr_2_Command is inputted into the




System Hardware as Cmd 2.


T1, T2, T#
Temperatures from
Temperature sensor output signals,



Temperature
preferably thermocouple outputs,



Sensors
multiple temperature sensor signals




monitored, including motor winding




temp, ambient temp, bearing race




temp, other temp sensors utilized to




sense a system failure, preferably




based on predetermined temp signal




maximums









In preferred embodiments the software program instructions work within the vibration control system hardware environment to provide the following functions:

    
    
        1. Start-up Mode: The software starts up the motors, preferably within 5 seconds such that minimal force is generated by the vibration control system using a soft start with the imbalance rotor mass concentrations oriented such that they are opposed.
        2. Vibration Control Mode The vibration control system preferably includes at least two orthogonal vibration sensor accelerometers oriented radially (FIG. 21 vibration sensor accelerometers 72). Preferably each accelerometer sensor is capable of measuring acceleration at a bandwidth of at least 1 Hz to 1000 Hz. Preferably the vibration control system 20 spins each imbalance rotor eccentric mass 40, 46 at a rate that is synchronous with the incoming tachometer signal and is an integer multiple (N) of the operational rotation frequency (N per rev) (in a preferred embodiment N=4). Preferably the vibration control system 20 adaptively adjust the phase of the eccentric masses of the imbalance rotors 38, 44 with respect to the tachometer signal in order to minimize the (N−1) per rev component of the accelerometer signals. Preferably the time constant associated with the adaptive vibration minimization is less than a second. Preferably the integer multiple of the operational rotation frequency corresponds to the number of helicopter blades and is between 10 and 25 Hz.
        3. Manual Mode: Preferably the software includes a manual mode whereby motor speeds and phases can be set manually through a RS-422 or similar serial communication link. In manual mode, the system has the option of operating from an external tachometer source or from an internally generated tachometer source.
        4. Over-speed Shutdown: Preferably the software monitors both imbalance rotor speeds and disables both current commands if either rotor speed exceeds a predetermined maximum speed. The software includes a means for system reset through the RS-422 serial communication link.
        5. High Temperature Shutdown: Preferably the software monitors the temperature within the vibration control system hardware and the motor windings and will disable both motor current commands if temperatures exceed a predetermined maximum operation temperature. The software provides a means for system reset through the RS-422 serial communication link.
    
    


In an embodiment the software control code program instructions preferably includes two nested feedback loops: the inner motor control loop and the outer vibration control loop, preferably such as shown in FIG. 1. The inner motor control loop closes a control loop around both motors 36, 42 based on rotor motor position feedback derived from motor position sensors, preferably from the rotor magnetic encoder rotor position sensor read heads 70. The inner loop servos the position of each motor (Motor 1, Motor 2) to track commands sent from the outer vibration control loop. These commands are in the form of absolute phase with respect to the externally provided tachometer (tach) signal. The inner loop I/O preferably includes the following signals:












I/O Signals
Description
Format







R1_phi, R2_phi
Commands from the
Step-wise DC levels



outer vibration control
updated at about 20 Hz.



loop.
Units of radians.


Tach,
External tachometer
A “counted” saw tooth


Tach_Theta

signal that wraps according




to modulo 2. Units of




radians.


R1_theta,
Encoder feedback,
A “counted” saw tooth


R2_theta
rotor position
signal that wraps according




to modulo 2. Units of




radians.


Mtr_1_Command,
Current commands
0-5 V output (filtered


Mtr_2_Command
sent to motor
PWM).



commutation



processors.









The outer vibration control loop receives two orthogonal acceleration signals from the vibration sensor accelerometer hardware 72 along with the reference tachometer and adaptively decides how the motors phases should be adjusted to minimize the accelerometer signals. The outer vibration control loop I/O preferably includes the following signals:












I/O Signals
Description
Format







R1_phi,
Commands to the inner
Step-wise DC levels


R2_phi
motor control loop.
preferably updated at about




20 Hz. Units of radians.


Tach,
External tachometer
A “counted” saw tooth signal


Tach_Theta

that wraps according to




modulo 2. Units of radians.


Vib X, Vib Y
Accelerometer feedback
Preferably 0-5 V input (10 bit



signals
A/D)









In addition preferably there is a Soft Start/Stop block that intelligently modifies the external tachometer signal to prevents abrupt commands to the control loops during motor start-up and shut-down, with computer program instructions to modify the tachometer signal when starting up the motors from rest or slowing down to rest, such that with such start/stop transitional speeds the imbalance rotors are maintained in an opposed orientation.
The Soft Start/Stop Control protocol program instructions preferably enables the motor controls, which are driven synchronously by the external tachometer input to be softly enabled or disabled. With the Soft Start/Stop Control protocol program instructions during a motor rotor system ramp up or ramp down, preferably the rotors are brought up or down in speed in Mode 1, which keeps the rotors in a neutralized state with the eccentric mass imbalance concentrations opposed. The ramping process can be controlled in a very deterministic manner. The ramp can be optimally shaped for each application. Preferably the soft start stop transitional rotation speed program instructions function with the Soft Start Control inserted in series to the external tachometer signal as shown in FIG. 1. FIG. 2 shows details of the Soft Start Block program instructions of a preferred embodiment.
This Soft Start Block program instructions blocks function to preserve the relative phase (per revolution) relationship of the input, the external tachometer and the output, but accommodates the large difference in absolute phase that is generated during a ramp up period. The ramp process preferably speeds up theta-out and locks on the closest integer multiple of the input tach. Theta-in and theta-out will always have the same relative phase, with an integer number of revolutions (N*2*) between them. The Soft Start process is shown in the soft start phase map of FIG. 3. Note theta-out locked onto a 2*pi multiple of theta-in−2*pi corresponds to one revolution, in radians. The overshoot region shows how the Soft Start preferably speeds up to the closest multiple of theta. This overshoot can be tuned to precisely control the maximum time allowed for the ramp up and phase lock process. Two examples of the Soft Start are shown in FIGS. 4 and 5. FIG. 4 shows experimental results of an implementation of a constant acceleration profile. FIG. 5 shows a simulated implementation of the soft start program instructions with the vibration control system. The overshoot is set at 5% of the commanded speed and the ramp rate is 1.5 Hz/sec. This profile is extremely deterministic in ramp up and ramp down time and is preferably governed by the following equation:

Ramp Time(max)=Command Speed/Ramp Rate+1/(% Overshoot*Command Speed)

FIG. 5 illustrates a simulated implementation of the soft start program instructions with the vibration control system. The algorithm program instructions shown in FIG. 2 demonstrate the constant acceleration ramp and allows for explicit design of the degree of overshoot and subsequent settling time.
In an embodiment a Tracking bandpass filter is preferably used to filter the vibration input sensors. This filter preferably tracks the periodic N per-rev frequency vibration that is targeted for vibration control. The use of such a tracking filter gives the vibration control algorithm excellent broadband and tonal noise rejection. The rotating helicopter hub mounted assembly application is harmonically rich with N per-rev tones, and preferably utilizes such a filter. FIG. 6 shows a preferred filter used with an embodiment of the vibration control software.
In an embodiment the Vibration Control Algorithm selected for the vibration control system is preferably an influence coefficient algorithm. A preferred influence coefficient algorithm is disclosed in U.S. Pat. No. 6,618,646 and U.S. Pat. No. 6,883,373 by Stephen Dyer, which are hereby incorporated by reference. In a current preferred embodiment, the algorithm is applied to a 3 per-rev shaft vibration of the rotating helicopter rotor hub 22. The algorithm is preferably implemented in a continuously running structure, with conditioned based stepping, as compared with a batch process. FIG. 7 shows the program instructions block diagram of this preferred implementation of the algorithm. In a preferred embodiment the influence coefficients are fixed for improved performance during transient conditions, with the fixed influence coefficients coming from a model system identification. In an alternative preferred embodiment the influence coefficient algorithm uses a recursive exponentially weighted averaging.
Conditioned based stepping preferably ensures that critical variables used by the algorithm are stable before executing a step of the algorithm. In an embodiment the algorithm preferably monitors each motor, and makes sure that previously commanded positions have been reached within some tolerance before the next step. The algorithm also monitors the accelerometers and makes sure that they have not been saturated by the analog-to-digital converter. An optional condition for stepping is monitoring the magnitude of the Fourier coefficients and determining if the coefficients are seeing a transient vibration condition. In a preferred embodiment vibration control is required during transient conditions, thus this condition is preferably disabled.
FIG. 8 shows an embodiment of a preferred Fourier coefficient filter (FFT coefficient filter) used by the algorithm. This filter uses sine and cosine signals that are generated from the tachometer and correspond to the frequency at which the rotating assembly vibration control system controls vibration. The output from the filter is the single frequency real and imaginary Fourier coefficients from each of the two accelerometer inputs. These coefficients are then added together in the complex plane to create the vector sum of the accelerometers as shown in FIG. 7. Vibration control on this vector sum optimally controls vibration on two orthogonal input accelerometers. In an embodiment the vibration control system implements the influence coefficient algorithm using C-code, such as in the Simulink block shown in FIG. 9.
The inner loop shown in FIG. 1 and expanded in FIG. 10 receives phase commands (R1_phi, R2_phi) from the outer loop vibration control and commands (Mtr_1_Command, Mtr_2_Command) the motors and the imbalance rotors to these phases using encoder feedback signals (R1_theta, R2_theta). As seen in FIG. 10, the motor command outputs can be manually disabled or disabled in the event of an overspeed condition. Preferably all signals in the control loop pertain to rotor position (in units of radians) and wrap every 2 thus characterized by a saw-tooth waveform of magnitude 2. Due to system causality, the feedback signal (e.g., R1_theta) will always lag the command signal. Therefore, at every wrap there will be a 2 discontinuity in the feedback error (e.g., err1) signal that will tend to maintain the system in a disruptive transient condition. A rollover continuity block [Rollover1] is therefore included in the loop. This block contains program instruction logic shown in the FIG. 11 rollover continuity logic to maintain error continuity through wrap condition of the feedback signal. The motor control block contains a 4th order compensator developed using frequency-shaping methods for proper command following, and ample gain and phase margins. This compensator preferably has the following s-domain form:




  
    i_cmd
    errc
  
  =
  
    
      K
      ⁡
      
        (
        
          
            p
            4
          
          
            z
            1
          
        
        )
      
    
    ⁢
    
      
        
          (
          
            s
            +
            
              z
              1
            
          
          )
        
        ⁢
        
          (
          
            s
            +
            
              z
              2
            
          
          )
        
      
      
        
          (
          
            
              s
              2
            
            +
            
              2
              ⁢
              ps
            
            +
            
              p
              2
            
          
          )
        
        2
      
    
  




Where zeros (z1 and z2) an poles (p) are placed using frequency-shaping methods. The z-domain implementation of this compensator is shown in the FIG. 12 motor control compensator. A resettable free integrator is also included in series with the compensator to eliminate steady state tracking error response to ramp-type inputs.

In an embodiment the method and system utilizes a motor control soft command. FIG. 13 shows an embodiment of a motor control soft command such as contained in the Soft Command block of FIG. 10. The Soft Command attempts to soften any abrupt changes in phase, or speed, which are input to the motor controls by the vibration control algorithm. The Soft Command block contains a first order model, which tracks the wrapping phase input commands. Preferably the Soft Command is analogous to a low pass filter in the wrapping phase domain. The motor controls have a very high bandwidth, so any abrupt changes in the input need to be filtered out or “softened” by the Soft Command block. Some of these abrupt changes include glitches in the input tachometer, large step changes in angle commanded by the vibration control algorithm, braking commands, which attempt to stop one motor as fast as possible and encoder glitches, which occur during startup, before the encoder has found the once per rev index pulse.
In an embodiment the vibration control system software program instructions include a fault mode control protocol. Preferably the control system software program instructions fault mode control protocol provides reversion control of the vibration control system upon failure of one of the motors/imbalance rotor. If during operation of the vibration control system 20, a fault causes one of the two motors to stop operating, that motor will come to a rest while the other motor continues to operate. The spin down of the failed motor will cause potentially large force transients during the initial deceleration. The other motor preferably continues spinning outputting half of the rated maximum vibration balancing force in that only a single imbalance mass rotor is driven. Preferably the program instructions monitor failure detecting sensors for a sensor signal indicating a failure event and control the failure event, preferably implementing the following actions to minimize the duration of the transient force interval and allow the remaining healthy motor to operate optimally:

    
    
        1. detect a motor failure using existing BIT or by detecting prolonged command tracking error,
        2. command both motors to the angle of the resultant correction force vector computed by the vibration control algorithm just prior to the motor failure (obviously, only one will respond),
        3. preferably simultaneously brake the failed motor such that it comes to rest quickly.

Step 2 is shown graphically in FIG. 14. Just prior to failure, both rotors (Rotor 1 solid vector 54 counterclockwise from dashed-Resultant vector 58) (Rotor 2 solid vector 56 clockwise from dashed-Resultant vector 58) are angularly positioned in order to create a resultant force (dashed-Resultant vector 58) of a magnitude (r_desired_mag) and phase (r_desired_phi) such that the disturbance force vector (solid-Disturbance vector 24) is cancelled. Upon the failure of one motor, both motors are commanded to r_desired_phi such that the disturbance force vector 24 is partially cancelled. FIG. 15 shows an embodiment of a block of C-code that has been used for step 2. The motor commands operate normally when both motors are enabled (Enable_R1==1, Enable_R2==1). When a fault is detected, one motor is disabled and the bottom else branch of the C code becomes active.

    
    


Braking of the motor (step 3) is a preferred optional step to minimize the transient force period that will result because the relative phase of the failed motor will wrap multiple times with respect to the healthy motor during deceleration. Braking of the failed motor can be accomplished by shorting one or more of the windings of the failed motor, such as shown in FIG. 25G-H, preferably using a relay or FET that is open when powered. These braking FETS act across the windings to brake the failed motor rotor. Redundancy is preferably accomplished by placing FETS across multiple windings and by placing FETS in series such that both have to fail closed in order to inadvertently short a given winding to electromagnetically brake it.
The single motor fault scenario is emulated and shown in FIG. 16, and was emulated by disabling one motor, commanding it to zero speed within 1 or 2 seconds and simultaneously implementing step 2 above. The results of such are shown in FIG. 16.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating vibration control system, preferably for a rotating wing hub assembly having a periodic vibration while rotating at an operational rotation frequency about an axis of rotation. The system includes a first motor with a first rotor with a first imbalance mass concentration. The system includes a second motor with a second rotor with a second imbalance mass concentration. The system includes an electronics control system which controls a speed and a phase of the first motor and the second motor such that the first imbalance mass concentration and the second imbalance mass concentration are driven at a vibration canceling rotation frequency wherein the periodic vibration is reduced.
In an embodiment the invention includes a method of controlling a periodic vibration of an assembly which rotates at an operational rotation frequency. The method includes providing an electronics housing cavity subsystem and a rotor housing cavity subsystem. The rotor cavity subsystem contains a first motor with a first rotor with a first imbalance rotor eccentric mass concentration. The rotor cavity subsystem contains a second motor having a second rotor with a second imbalance rotor eccentric mass concentration. The electronics housing cavity subsystem contains an electronics control system which controls the speed and phase of the first motor and the second motor. The method includes electromagnetically driving, preferably directly driving, the first rotor and the second rotor at a vibration canceling rotation frequency while controlling the rotational phase position of the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration in order to produce a net force vector to inhibit and balances out the periodic vibration. The electronic control system processes sensor inputs to determine the orientation and speed of the rotors, and calculates and modifies the speed and orientation of the rotors in order to cancel and balance out the unwanted vibrations.
In an embodiment the invention includes a method of controlling a periodic vibration. The method includes driving a first imbalance rotor and a second imbalance rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance rotor eccentric mass concentration and the rotational position of the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration.
In an embodiment the helicopter rotating hub mounted vibration control system 20 includes an annular ring rotary housing attachable to the helicopter rotary wing hub and rotating with the helicopter rotary wing hub at the helicopter operational rotation frequency. The annular ring housing is centered about the rotary wing hub axis of rotation and preferably has an electronics housing cavity subsystem. The housing preferably includes a first motor, most preferably a coaxial frameless AC ring motor. The first motor preferably has a first rotor with a first imbalance mass. The housing preferably includes a second motor, most preferably a coaxial frameless AC ring motor. The second motor preferably has a second rotor with a second imbalance mass. The electronics housing cavity subsystem contains an electronics control system which utilizes electronic inputs and outputs and electrically controls and drives the first motor and the second motor such that the first imbalance mass and the second imbalance mass are driven, preferably directly driven, at a vibration canceling rotation frequency preferably greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced. Preferably electronics control system housed in the electronics housing cavity subsystem executes the program instructions to control the vibration controls system and minimized troublesome vibrations.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating vibration control system 20 for a rotating wing hub assembly 22 having a periodic vibration while rotating at an operational rotation frequency about an axis of rotation. The system includes a first motor with a first rotor with a first imbalance mass concentration. The system includes a second motor with a second rotor with a second imbalance mass concentration. The system includes an electronics control system which controls a speed and a phase of the first motor and the second motor such that the first imbalance mass concentration and the second imbalance mass concentration are driven at a vibration canceling rotation frequency wherein the periodic vibration is reduced. Preferably the electronics control system executes program instructions to drive the first and second motors.
In an embodiment the invention includes a method of controlling a periodic vibration of an assembly which rotates at an operational rotation frequency. The method includes providing an electronics housing cavity subsystem and a rotor housing cavity subsystem. The rotor cavity subsystem contains a first motor with a first rotor with a first imbalance rotor eccentric mass concentration. The rotor cavity subsystem contains a second motor having a second rotor with a second imbalance rotor eccentric mass concentration. The electronics housing cavity subsystem contains an electronics control system which controls the speed and phase of the first motor and the second motor. The method includes electromagnetically driving, preferably directly driving, the first rotor and the second rotor at a vibration canceling rotation frequency while controlling the rotational phase position of the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration in order to produce a net force vector to inhibit and balances out the periodic vibration. The electronic control system processes sensor inputs to determine the orientation and speed of the rotors, and calculates and modifies the speed and orientation of the rotors in order to cancel and balance out the unwanted vibrations. Preferably the electronics control system executes program instructions to drive the first and second motors.
In an embodiment the invention includes a method of controlling a periodic vibration. The method includes driving a first imbalance rotor and a second imbalance rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance rotor eccentric mass concentration and the rotational position of the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration.
In an embodiment the invention includes a computer programmable media containing programmable software to control a rotating assembly helicopter rotating hub mounted vibration control system 20 with a first imbalance mass concentration rotor 38 and a second imbalance mass concentration rotor 44, for a rotating assembly 22 having a periodic vibration 24 while rotating at an operational rotation frequency 26. Preferably the computer programmable media is integrated in the electronics control system. The computer programmable software includes first motor and vibration control program instructions for rotating the first imbalance mass concentration rotor and the second imbalance mass concentration rotor at a whole number multiple vibration canceling rotation frequency 52 greater than the rotating assembly operational rotation frequency 26 while controlling the rotational position of the first imbalance mass concentration 40 and the second imbalance mass concentration 46 to produce a rotating net force vector 58 to inhibit the periodic vibration 24. The computer programmable software includes second soft start/stop program instructions to opposingly orient the first imbalance mass concentration 40 relative to the second imbalance mass concentration 46 during a transitioning starting stopping rotation speed less than the whole number multiple vibration canceling rotation frequency. The soft start/stop program instructions provide for opposingly orienting the first imbalance mass concentration 40 relative to the second imbalance mass concentration 46, such as shown in FIG. 20D, during both a rotation speed ramp up at system start and a rotation speed ramp down at a system stop. Preferably the soft start stop program instructions provide for starting and stopping transitioning rotational speed based instructions to opposingly orient the first imbalance mass concentration rotor relative to the second imbalance mass concentration rotor. The computer programmable software preferably includes third program instructions including a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system, preferably including motor control servo instructions to position the first rotor to track a first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track a second rotor command (R2_phi). Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to a resultant phase (F_phase) angular position 58 (Resultant dashed vector 58 phase angular position) which opposes the angular position of disturbance force vector 24 (Disturbance solid vector position 24) such as shown in FIG. 14. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to resultant phase (F_phase) position such as shown in FIG. 14 As shown in FIG. 1, the Influence Coefficient Algorithm block preferably calculates F_Magnitude and F_phase as the resultant vector that is needed to oppose the disturbance force vector 24 (Disturbance solid vector position 24) (problematic vibration force 24), with the F_Magnitude and F_phase preferably inputted into the Generate Motor Commands block as Magnitude and Phase, which are then preferably used to calculate the angular positions [first rotor (R1_phi), second rotor (R2_phi)] of vector 54 and vector 56 needed to produce Resultant dashed vector 58 to oppose and cancel disturbance force vector 24. Prior to detecting a rotor failure, preferably the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position are derived from the F_Magnitude and F_phase resultant vector 58 (the vectors 54 and 56 combine into resultant vector 58, resultant vector 58 being at an angular median position between the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position). When a rotor/motor failure is detected the remaining working rotor is preferably commanded to the F_Magnitude and F_phase resultant vector 58 since the failed rotor/motor can not be properly commanded to produce a vector (54 or 56) since its angular position can not be commanded or controlled. As shown in FIG. 15, F_phase (Phase in Generate Motor Commands block) is *r_desired_phi and R1_phi is *R1_phi_desired and R2_phi is *R2_phi_desired.
In an embodiment the invention includes computer program product for controlling a rotating vibration control system, preferably rotating vibration control system 20, with a first motor driven imbalance mass concentration rotor and a second motor driven imbalance mass concentration rotor. The computer program product includes a computer readable medium, first (motor and vibration control) program instructions for driving the first imbalance mass concentration rotor and the second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration to produce a net force vector to inhibit a vibration, second (soft start/stop) program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a transitioning (starting/stopping) rotation speed. Preferably the soft start and stop instructions are used for 1 per rev and greater rotation applications. Preferably the instruction include opposing rotor orientation before and after the vibration control operation, such as during startup and shut down of the control system 20, with rotor opposition maintained until proper operation rotation speed and phase is matched, with the transitioning speed different from the vibration canceling rotation frequency. Preferably the transitioning speed is less than vibration canceling rotation frequency. Preferably a majority of the transitioning speed is less than vibration canceling rotation frequency, such as shown in the FIG. 3 phase map, with a greater speed overshoot used to match phase with the speed then reduced down to the vibration canceling rotation frequency. The program instructions for soft start/stop are used for a rotation speed ramp up, and the soft start stop program instructions includes rotational speed based instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a rotation speed ramp down. Preferably the computer program instructions include program instructions for monitoring a tachometer input signal. Preferably the computer program instructions for monitoring tachometer input signal include maintaining an opposing orientation of the first imbalance mass concentration and the second imbalance mass concentration unless the rotors are driving in sync with the tachometer input signal. Preferably the computer program instructions include a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating vibration control system. Preferably the computer program instructions include motor control servo instructions to position the first rotor to track a first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track a second rotor command (R2_phi). Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the fault mode control protocol for controlling rotation of the rotors during a sensed failure of the rotating assembly vibration control system includes motor control servo instructions to position the first rotor to track a first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track a second rotor command (R2_phi). Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to a resultant phase (F_phase) angular position 58 (Resultant dashed vector 58 phase angular position) which opposes the angular position of disturbance force vector 24 (Disturbance solid vector 24) such as shown in FIG. 14. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to resultant phase (F_phase) position such as shown in FIG. 14. As shown in FIG. 1, the Influence Coefficient Algorithm block preferably calculates F_Magnitude and F_phase as the resultant vector that is needed to oppose the disturbance force vector 24 (Disturbance solid vector position 24) (problematic vibration force 24), with the F_Magnitude and F_phase preferably inputted into the Generate Motor Commands block as Magnitude and Phase, which are then preferably used to calculate the angular positions [first rotor (R1_phi), second rotor (R2_phi)] of vector 54 and vector 56 needed to produce Resultant dashed vector 58 to oppose and cancel disturbance force vector 24. Prior to detecting a rotor failure, preferably the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position are derived from the F_Magnitude and F_phase resultant vector 58 (the vectors 54 and 56 combine into resultant vector 58, resultant vector 58 being at an angular median position between the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position). When a rotor/motor failure is detected the remaining working rotor is preferably commanded to the F_Magnitude and F_phase resultant vector 58 since the failed rotor/motor can not be properly commanded to produce a vector (54 or 56) since its angular position can not be commanded or controlled. As shown in FIG. 15, F_phase (Phase in Generate Motor Commands block) is *r_desired_phi and R1_phi is *R1_phi_desired and R2_phi is *R2_phi_desired.
In an embodiment the invention includes a computer program product for controlling a rotating assembly vibration control system. The computer program product includes a computer readable medium, a first motor control program instructions to control a rotation of a first driven rotor and a rotation of a second driven rotor, second vibration sensor monitoring program instructions to monitor a plurality of sensor signals, and third vibration control program instructions to control the rotation speed and phase of the first rotor and the rotation speed and phase of the second rotor to minimize a monitored vibration sensor signal. The computer program product preferably includes a vibration control loop, the vibration control loop including an influence coefficient algorithm, the vibration control loop influence coefficient algorithm outputting a first rotor command (R1_phi) and a second rotor command (R2_phi) into the inner motor control loop. The computer program product preferably includes a sensor filter for filtering the sensor signals to provide a filtered first vibration sensor signal (Filtered X) and a filtered second vibration sensor signal (Filtered Y), the filtered first vibration sensor signal (Filtered X) and the filtered second vibration sensor signal (Filtered Y) inputted into the vibration control loop influence coefficient algorithm. The computer program product preferably includes an inner motor control loop which closes a control loop around a first motor and a second motor based on a first rotor position feedback derived from a first rotor rotational position sensor signal and a second rotor position feedback derived from a second rotor rotational position sensor signal. The computer program product preferably includes motor control servo instructions to position the first rotor to track the first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track the second rotor command (R2_phi). The computer program product preferably includes soft start stop program instructions, the soft start stop program instructions providing commands to the motor control loop to opposingly orient a first rotor first imbalance mass concentration relative to a second rotor second imbalance mass concentration. The computer program product preferably includes soft start stop program instructions with a rotational speed based instruction to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a rotation speed ramp up. The computer program product preferably includes soft start stop program instructions including a rotational speed based instruction to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a rotation speed ramp down. The computer program product preferably includes instructions for driving the first rotor and the second rotor at a whole number multiple vibration canceling rotation frequency greater than a rotating assembly operational rotation frequency. The computer program product preferably includes soft start stop program instructions to opposingly orient the first rotor relative to the second rotor during a transitioning starting stopping rotation speed less than the whole number multiple vibration canceling rotation frequency. The computer program product preferably includes a fault mode control protocol for controlling a rotation of the rotors during a sensed failure of the rotating assembly vibration control system, preferably wherein the fault mode control protocol includes instructions for monitoring sensor signals and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring sensor signals and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the fault mode control protocol for controlling rotation of the rotors during a sensed failure of the rotating assembly vibration control system includes motor control servo instructions to position the first rotor to track a first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track a second rotor command (R2_phi). Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to a resultant phase (F_phase) angular position 58 (Resultant dashed vector 58 phase angular position) which opposes the angular position of disturbance force vector 24 (Disturbance solid vector position 24) such as shown in FIG. 14. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to resultant phase (F_phase) position such as shown in FIG. 14. As shown in FIG. 1, the Influence Coefficient Algorithm block preferably calculates F_Magnitude and F_phase as the resultant vector that is needed to oppose the disturbance force vector 24 (Disturbance solid vector position 24) (problematic vibration force 24), with the F_Magnitude and F_phase preferably inputted into the Generate Motor Commands block as Magnitude and Phase, which are then preferably used to calculate the angular positions [first rotor (R1_phi), second rotor (R2_phi)] of vector 54 and vector 56 needed to produce Resultant dashed vector 58 to oppose and cancel disturbance force vector 24. Prior to detecting a rotor failure, preferably the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position are derived from the F_Magnitude and F_phase resultant vector 58 (the vectors 54 and 56 combine into resultant vector 58, resultant vector 58 being at an angular median position between the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position). When a rotor/motor failure is detected the remaining working rotor is preferably commanded to the F_Magnitude and F_phase resultant vector 58 since the failed rotor/motor can not be properly commanded to produce a vector (54 or 56) since its angular position can not be commanded or controlled. As shown in FIG. 15, F_phase (Phase in Generate Motor Commands block) is *r_desired_phi and R1_phi is *R1_phi_desired and R2_phi is *R2_phi_desired.
In an embodiment the invention includes a rotating assembly helicopter rotating hub mounted vibration control system 20 for a rotating machine assembly 22 having a periodic operational vibration 24 while rotating at an operational rotation frequency 26. Preferably the system 20 includes motors for driving the rotation of imbalance weights, preferably at least two motor for directly driving the rotation of imbalance weight rotors, preferably gearlessly directly driven without mechanical gears coupling and transmitting the motion. The vibration control system 20 preferably includes a housing having an electronics housing cavity subsystem, a first coaxial frameless AC ring motor having a first rotor with a first imbalance mass concentration, the first motor directly driving a rotation of the first rotor, a second coaxial frameless AC ring motor having a second rotor with a second imbalance mass concentration, the second motor directly driving a rotation of the second rotor, an electronics control system which controls a speed and a phase of the first motor and the second motor, a first vibration sensor accelerometer for producing a first vibration sensor signal, a second vibration sensor accelerometer for producing a second vibration sensor signal, a first rotor rotational position sensor, a second rotor rotational position sensor, a inner motor control loop for controlling the rotation of the first rotor and the rotation of the second rotor, a outer vibration control loop for providing commands to the motor control loop to control the rotation of the first rotor and the rotation of the second rotor to minimize the first vibration sensor signal and the second vibration sensor signal. Preferably the motor control loop is an inner motor control loop including a first motor control and a second motor control, and the vibration control loop is an outer vibration control loop, the outer vibration control loop including an influence coefficient algorithm, the outer vibration control loop influence coefficient algorithm outputting a first rotor command (R1_phi) into the inner motor control loop first motor control and a second rotor command (R2_phi) into the inner motor control loop second motor control. Preferably the outer vibration control loop including an ALE bandpass filter, the bandpass filter filtering the first vibration sensor signal to provide a filtered first vibration sensor signal (Filtered X) and filtering the second vibration sensor signal to provide a filtered second vibration sensor signal (Filtered Y), the filtered first vibration sensor signal (Filtered X) and the filtered second vibration sensor signal (Filtered Y) inputted into the outer vibration control loop influence coefficient algorithm. Preferably the inner motor control loop closes a control loop around the first and second motors based on a first rotor position feedback derived from the first rotor rotational position sensor and a second rotor position feedback derived from the second rotor rotational position sensor. Preferably the inner motor control loop servos a position of the first rotor to track the first rotor command (R1_phi) outputted from the outer vibration control loop influence coefficient algorithm and a position of the second rotor to track the second rotor command (R2_phi) outputted from the outer vibration control loop influence coefficient algorithm. Preferably the system includes a soft start stop transitioning rotation speed control subsystem with program instructions including a start stop transitioning rotation speed protocol, the soft start stop control subsystem providing commands to the motor control loop to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration. Preferably the soft start stop control subsystem includes program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a rotation speed ramp up. Preferably the soft start stop control subsystem includes program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a rotation speed ramp down. Preferably the vibration control system rotates the first rotor and the second rotor at a whole number multiple vibration canceling rotation frequency greater than an operational rotation frequency of the assembly producing the operational vibration. Preferably the soft start stop control subsystem includes program instructions to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration during a transitioning starting stopping rotation speed less than the whole number multiple vibration canceling rotation frequency. Preferably the system includes a fault mode control protocol for controlling a rotation of the rotors during a failure of the rotating assembly vibration control system. Preferably the fault mode control protocol includes detecting a first motor failure. Preferably the fault mode control protocol includes detecting a second motor failure. Preferably the first motor is commanded to a prefailure first rotor (R1_phi) command angular position and the second motor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first motor failure, and upon detecting the first motor failure the second motor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the first motor is commanded to a prefailure first rotor (R1_phi) command angular position and the second motor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second motor failure, and upon detecting the second motor failure the first motor is commanded to an angular median position between the prefailure first rotor (R1_phi) command angular position and the prefailure second rotor (R2_phi) command angular position. Preferably the fault mode control protocol for controlling rotation of the rotors during a sensed failure of the rotating assembly vibration control system includes motor control servo instructions to position the first rotor to track a first rotor command (R1_phi) and motor control servo instructions to position the second rotor to track a second rotor command (R2_phi). Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a first rotor failure. Preferably the fault mode control protocol includes instructions for monitoring a sensor signal and detecting a second rotor failure. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the first rotor failure, and upon detecting the first rotor failure the second rotor is commanded to a resultant phase (F_phase) angular position 58 (Resultant dashed vector 58 phase angular position) which opposes the angular position of disturbance force vector 24 (Disturbance solid vector position 24) such as shown in FIG. 14. Preferably the first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and the second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to the second rotor failure, and upon detecting the second rotor failure the first rotor is commanded to resultant phase (F_phase) position such as shown in FIG. 14. As shown in FIG. 1, the Influence Coefficient Algorithm block preferably calculates F_Magnitude and F_phase as the resultant vector that is needed to oppose the disturbance force vector 24 (Disturbance solid vector position 24) (problematic vibration force 24), with the F_Magnitude and F_phase preferably inputted into the Generate Motor Commands block as Magnitude and Phase, which are then preferably used to calculate the angular positions [first rotor (R1_phi), second rotor (R2_phi)] of vector 54 and vector 56 needed to produce Resultant dashed vector 58 to oppose and cancel disturbance force vector 24. Prior to detecting a rotor failure, preferably the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position are derived from the F_Magnitude and F_phase resultant vector 58 (the vectors 54 and 56 combine into resultant vector 58, resultant vector 58 being at an angular median position between the prefailure first rotor (R1_phi) command angular position and the second rotor (R2_phi) command angular position). When a rotor/motor failure is detected the remaining working rotor is preferably commanded to the F_Magnitude and F_phase resultant vector 58 since the failed rotor/motor can not be properly commanded to produce a vector (54 or 56) since its angular position can not be commanded or controlled. As shown in FIG. 15, F_phase (Phase in Generate Motor Commands block) is *r_desired_phi and R1_phi is *R1_phi_desired and R2_phi is *R2_phi_desired. Preferably upon detecting the first motor failure the first motor is braked, preferably electromagnetically braked with a braking circuit, such as shown in FIGS. 25G&H. Preferably upon detecting the second motor failure the second motor is braked, preferably electromagnetically braked with a braking circuit, such as shown in FIGS. 25G&H. Preferably the first imbalance mass concentration and the second imbalance mass concentration are directly driven at a whole number multiple vibration canceling rotation frequency greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced. Preferably the first motor first rotor has a target and the second motor second rotor has a target, and the system contains at least two target sensing read heads that senses the rotor targets.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating hub mounted vibration control system for a helicopter rotary wing hub having a periodic vibration while rotating at a helicopter operational rotation frequency. The helicopter rotating hub mounted vibration control system includes an annular ring rotary housing attachable to the helicopter rotary wing hub and rotating with the helicopter rotary wing hub at the helicopter operational rotation frequency. The annular ring housing is centered about the rotary wing hub axis of rotation and has an electronics housing cavity subsystem and an adjacent coaxial rotor housing cavity subsystem. The rotor housing cavity subsystem contains a first coaxial frameless AC ring motor having a first rotor with a first imbalance mass and a second coaxial frameless AC ring motor having a second rotor with a second imbalance mass. The electronics housing cavity subsystem contains an electronics control system which receives sensor outputs and electrically controls and drives the first coaxial frameless AC ring motor and the second coaxial frameless AC ring motor such that the first imbalance mass and the second imbalance mass are directly driven at a vibration canceling rotation frequency greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating vibration control system for a helicopter rotary wing hub having a periodic vibration while rotating at a helicopter operational rotation frequency about a rotary wing axis of rotation. The helicopter rotating vibration control system includes a rotary housing centered about and encompassing the rotary wing axis of rotation with the rotary housing rotating at the helicopter operational rotation frequency. The rotating rotary housing contains a first coaxial ring motor coaxially centered about the rotary wing axis of rotation. The first coaxial ring motor has a first rotor with a first imbalance mass concentration. The rotating rotary housing contains a second coaxial ring motor coaxially centered about the rotary wing axis of rotation with the second coaxial ring motor having a second rotor with a second imbalance mass concentration. The rotating rotary housing contains an electronics control system which controls a speed and a phase of the first coaxial ring motor and the second coaxial ring motor such that the first imbalance mass concentration and the second imbalance mass concentration are directly driven at a whole number multiple vibration canceling rotation frequency greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced.
In an embodiment the invention includes a method of controlling a periodic vibration of a rotary wing aircraft helicopter with a helicopter rotary wing hub, which rotates at an operational rotation frequency. The method includes providing an annular ring housing having an electronics housing cavity subsystem and an adjacent coaxial rotor housing cavity subsystem. The rotor cavity subsystem contains a first coaxial ring motor coaxially centered about the rotary wing hub axis of rotation. The first coaxial ring motor has a first rotor with a first imbalance rotor eccentric mass concentration. The rotor cavity subsystem contains a second coaxial ring motor having a second rotor with a second imbalance rotor eccentric mass concentration, and a lubricant. The electronics housing cavity subsystem contains an electronics control system which controls the speed and phase of the first coaxial ring motor and the second coaxial ring motor. The method includes securing the annular ring housing to the helicopter rotary wing hub with the annular ring housing rotating at the operational rotation frequency. The method includes directly electromagnetically driving the first rotor and the second rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational phase position of the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit and balances out the periodic vibration. The electronic control system processes sensor inputs, determines the orientation and speed of the rotors, and calculates and modifies the speed and orientation of the rotors in order to cancel and balance out the unwanted vibrations.
In an embodiment the invention includes a method of making a helicopter rotating hub mounted vibration control system for a helicopter rotary wing hub having a periodic vibration while rotating at an operational rotation frequency. The method includes providing a rotary housing having an electronics housing cavity and a rotor housing cavity. The provided rotor housing cavity preferably contains a first coaxial frameless ring driver motor having a first rotor with a first imbalance rotor eccentric mass concentration, a second coaxial frameless ring driver motor having a second rotor with a second imbalance rotor eccentric mass concentration, with the rotor housing cavity including a circumferential surface. The provided electronics housing cavity preferably contains an electronics control system which controls and drives the speed and phase of the first coaxial frameless ring motor and the second coaxial brushless frameless ring motor. The method preferably includes sealing a lubricant inside the rotor housing cavity, wherein the lubricant collects along the circumferential surface when the annular ring housing rotates at the helicopter operational rotation frequency.
In an embodiment the invention includes a vibration control balancer system, which rotates about a center axis of rotation at an operational rotation frequency. The rotating vibration balancer includes a first stator having a plurality of electromagnets with the electromagnets periodically spaced around the center axis of rotation, and a first imbalance rotor having a mass concentration, the first imbalance rotor including magnets periodically spaced around the center axis of rotation with the first imbalance rotor adjacent the first stator. The rotating vibration balancer includes a second stator having a plurality of electromagnets periodically spaced around the center axis of rotation, and a second imbalance rotor having a having a mass concentration and a plurality of magnets periodically spaced around the center axis of rotation, with the second imbalance rotor adjacent the second stator. The first stator electromagnets generate magnetic fields to move and directly drive the first imbalance rotor magnets and the first imbalance rotor eccentric mass concentration around the center axis of rotation at a vibration canceling rotation frequency greater than the operational rotation frequency, and the second stator electromagnets directly drive and move the second imbalance rotor magnets and the second imbalance rotor eccentric mass concentration around the center axis of rotation at the vibration canceling rotation frequency.
In an embodiment the invention includes a method of controlling a periodic vibration of a helicopter with a helicopter rotary wing hub, which rotates about a center axis of rotation at an operational rotation frequency. The method includes providing a first stator having electromagnets periodically spaced around the center axis of rotation, and providing a first imbalance rotor having an eccentric mass concentration and a plurality of magnets periodically spaced around the center axis of rotation. The method includes disposing and coupling the first imbalance rotor around the first stator such that the first stator electromagnets directly drive the first imbalance rotor magnets and the first imbalance rotor eccentric mass concentration around the center axis of rotation. The method includes providing a second stator having a plurality of electromagnets periodically spaced around the center axis of rotation, and providing a second imbalance rotor having an eccentric mass concentration and a plurality of magnets periodically spaced around the center axis of rotation. The method includes disposing and coupling the second imbalance rotor around the second stator such that the second stator electromagnets directly drive the second imbalance rotor magnets and the second imbalance rotor eccentric mass concentration around the center axis of rotation. The method includes directly driving the first rotor and the second rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance rotor eccentric mass concentration and the rotational position of the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration.
In an embodiment the invention includes a method of making a vibration control device, which rotates about a center axis of rotation at an operational rotation frequency. The method includes providing a rotary housing. The method includes providing a first stator having a plurality of electromagnets periodically spaced around the center axis of rotation, and providing a first imbalance rotor having an eccentric mass concentration and a plurality of magnets periodically spaced around the center axis of rotation. The method includes coupling the first imbalance rotor around first stator such that the first stator electromagnets directly drive the first imbalance rotor magnets and the first imbalance rotor eccentric mass concentration around the center axis of rotation. The method includes providing a second stator having a plurality of electromagnets periodically spaced around the center axis of rotation and a second imbalance rotor having an eccentric mass concentration and a plurality of magnets periodically spaced around the center axis of rotation. The method includes coupling the second imbalance rotor around the second stator such that the second stator electromagnets directly drive the second imbalance rotor magnets and the second imbalance rotor eccentric mass concentration around the center axis of rotation. The method includes sealing the coupled first imbalance rotor and the first stator and the coupled second imbalance rotor and the second stator in the rotary housing with a liquid lubricant.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating hub mounted vibration balancing control system. The helicopter rotating hub mounted vibration control system includes an annular ring rotary housing for attachment with the helicopter with the housing rotating at the helicopter operational rotation frequency. The annular ring rotary housing is centered about the rotary wing hub axis of rotation. The housing preferably includes an electronics housing cavity and a rotor housing cavity. The rotor housing cavity contains a first coaxial frameless AC ring motor having a first rotor with a first imbalance rotor eccentric mass concentration and a second coaxial frameless AC ring motor having a second rotor with a second imbalance rotor eccentric mass concentration. The electronics housing cavity contains a electronics control system which controls the position and motion of the first coaxial frameless AC ring motor and the second coaxial frameless AC ring motor such that the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration are directly driven at a vibration canceling rotation frequency greater than the helicopter operational rotation frequency wherein the helicopter rotary wing hub periodic vibration is reduced. Preferably the annular ring rotary housing is centered about the rotary wing hub axis of rotation, with both the electronics housing cavity and the rotor housing cavity subsystems encompassing the helicopter rotary wing hub axis of rotation. Preferably the annular ring rotary housing, preferably with both the electronics housing cavity and the rotor housing cavity subsystems, encompasses the helicopter rotor shaft.
FIG. 17 shows a preferred rotary wing aircraft helicopter rotating hub mounted vibration control system 20 for a helicopter rotary wing hub 22 having a periodic vibration 24 while rotating at a helicopter operational rotation frequency 26. As shown in FIG. 18 preferred helicopter rotating hub mounted vibration control system 20 includes an annular ring rotary housing 30. The annular ring rotary housing 30 is attached to the helicopter rotary wing hub 22 and rotates with the helicopter rotary wing hub 22 and rotor shaft 29 at the helicopter operational rotation frequency 26. The annular ring housing has an electronics housing cavity subsystem 32 and a rotor housing cavity subsystem 34. Preferably the housing 30 is centered about the rotary wing hub axis of rotation 28 with both the electronics housing cavity subsystem and the rotor housing cavity subsystem encompassing the helicopter rotary wing hub axis of rotation 28. The rotor housing cavity subsystem 34 contains a first coaxial brushless frameless AC ring motor 36 coaxially centered about the rotary wing hub axis of rotation 28 and having a first imbalance rotor 38 with a first imbalance rotor eccentric mass concentration 40. The rotor housing cavity subsystem 34 contains a second coaxial frameless AC ring motor 42 coaxially centered about the rotary wing hub axis of rotation 28 having a second rotor 44 with a second imbalance rotor eccentric mass concentration 46. Such as shown in FIG. 19, preferably the rotor housing cavity subsystem 34 contains a lubricant 48, preferably a liquid fluid lubricant. The electronics housing cavity subsystem 32 contains a electronics control system 50 which measures the periodic vibration 24 and controls the speed, relative phase and absolute phase of the first coaxial brushless frameless AC ring motor 36 and the second coaxial brushless frameless AC ring motor 42 such that the first imbalance rotor and eccentric mass concentration 40 and the second imbalance rotor and eccentric mass concentration 46 are directly driven at a whole number multiple vibration canceling rotation frequency 52 greater than the helicopter operational rotation frequency 26 wherein the helicopter rotary wing hub periodic vibration 24 is reduced. In a preferred embodiment the housing 30 is spinning at 1 per rev with the helicopter rotary wing hub 22 and the imbalance rotor eccentric mass concentrations 40 and 46 spinning at N per rev, with the motors 36, 42 directly driving the imbalance rotors 38 and 44 at (N−1) per rev relative to the housing 30 and in the same rotation direction as the housing. This preferred embodiment N=4 is particularly applicable to four bladed helicopters. As shown in FIG. 20, the first motor 36 produces a first rotating force 54 {F1=mr w12, where mr is the first rotor imbalance and w1 is the first rotor spinning speed} and the second motor 42 produces a second rotating force 56 which combine to produce a rotating net force vector 58 to cancel the periodic vibration force 24. In preferred embodiments the rotor housing cavity subsystem 34 is comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62, with the upper and lower rotor cavity 60 and 62 separated so that particle contaminates and spall debris from one rotor does not contaminate other rotor, preferably with the upper and lower liquid lubricated cavities 60 and 62 liquidly isolated from each other. Preferably the first coaxial frameless AC ring motor first rotor 38 has a lubricated bearing 64 for supporting the first rotor relative to the housing 30, the first rotor bearing 64 lubricated by a liquid lubricant 48, and the second coaxial frameless AC ring motor second rotor 44 has a lubricated bearing 66 for supporting the second rotor relative to the housing 30, with the second rotor bearing 66 lubricated by a lubricant 48. Preferably the bearings 64 and 66 are thin section bearings with the thickness, height, width of the bearing (h) much less than the radius of bearing r, h<<r. The first coaxial brushless frameless AC ring motor first rotor 38 has at least one target 68 and the second coaxial frameless AC ring motor second rotor 44 has at least one target 68, and the rotor cavity subsystem contains at least one target sensing read head 70 per rotor that senses the rotor targets 68, with the sensor targets and read heads providing for sensing the rotational position and movement of the rotors 38 and 44, preferably with each rotor having a plurality of targets, preferably a plurality of multi-pole magnetic targets. Preferably the targets 68 and the sensor read heads 70 are lubricant resistant and tolerate and operate in the liquid lubricant environment of the rotor housing cavity subsystem 34. In embodiments the sensor read heads 70 are chosen from the sensor group consisting of variable reluctance sensors, resolvers, encoders, and magnetic sensors that sense the separate target magnets 68 of the rotors and tolerate the bearing lubricant environment inside the rotor housing cavity subsystem 34, and have sensing operation that is lubricant resistant to the liquid oil splashing environment. In a preferred embodiment the sensor read heads 70 are Hall effect magnetic sensors for sensing rotor target magnets, with the Hall effect sensor positioned proximate the rotor and adapted to generate an output signal from the passing of the magnet with the Hall effect sensor output received by the electronic control system. The target sensing read heads 70 transmit and communicate with the electronics control system so the electronics control system tracks and has information on the angular position of the rotors 38 and 44, particularly the orientation rotors and the rotational angular position of the imbalance rotor eccentric mass concentrations 40 and 46. The rotational positions sensed by the target sensing read heads 70 is used to drive the rotors with the motors and as feedback for the motor's amplifiers, and also is used to position the imbalance concentrations 40 and 46 relative to the problematic rotor vibration as sensed by the accelerometers of the electronics control system. The sensed rotor position is fed back to the motor amplifiers in order to commutate the motor and to control further driving of the rotor. Preferably at least two vibration sensor accelerometers 72 are utilized by the electronics control system to sense the vibration 24, and most preferably four orthogonally positioned vibration sensor accelerometers 72 are spaced around the axis of rotation 28 and sense the problematic periodic vibration 24, preferably with the vibration sensor accelerometers providing for an X and Y coordinate system description of the sensed vibration 24 (ACCEL X, ACCEL Y). Preferably the electronics control system receives input from the helicopter regarding the operation of the helicopter, preferably including a helicopter tachometer input with a signal synchronized with the rotation speed helicopter operational rotation frequency 26 of the helicopter rotary wing hub 22, and provides the electronics control system with the speed of rotor blades and a reference point for the phase of the helicopter rotary wing hub 22, such as a three phase 400 Hz AC signal into a Tach Conditioning Circuit. The electronics control system drives the imbalance rotors 38 and 44 at the N per rev vibration canceling rotation frequency 52, and positions the rotors eccentric masses 40 and 46 at relative rotational phases so the vibration 24 sensed by the accelerometers 72 is minimal, with rotors phase and speed controlled to produce the net sum vibration canceling force 58 to counteract the problem vibration 24, preferably using a gradient decent algorithm method. Preferably the electronics control system accelerometers 72 sense the problem vibration 24, and the imbalance rotors 38 and 44 rotational phase positions are controlled with each rotor producing a rotating force vector which add up to the net disturbance force vector 58 with a direction and magnitude that counteract the problem vibration 24 and minimizes the vibration sensed by the accelerometers 72. The electronic control system processor receives sensor outputs to determine the orientation and angular positions of the rotors relative to the problematic vibrations and calculates and modifies the movement of the rotors with generated magnetic fields in order to change the amount of vibration sensed by the accelerometers. Preferably the rotor housing cavity 34 includes a circumferential surface 74 that constrains the liquid lubricant 48 while the housing 30 is rotating at the helicopter operational rotation frequency 26. With the rotation of the vibration control system housing 30 the liquid lubricant collects against the wall surface 74. Preferably the imbalance rotors include at least one lubricant mover 76 that disturbs the lubricant 48 collecting at the wall surface 74 in order to circulate the lubricant for the bearings 64 and 66. The lubricant mover 76 may include the bearing and rotor members moving through the lubricant such that the liquid lubricant is moved and preferably circulated through and around the bearings 64 and 66. Preferably the lubricant movers 76 radially extend out from the imbalance rotors 38 and 44 rotors towards the circumferential surface 74 and with the lubricant movers 76 moving and disturbing the constrained liquid lubricant 48. As shown in FIG. 22-23, in embodiments the lubricant movers 76 are radially extending scoops that scoop and direct the liquid lubricant towards the bearing. Preferably the lubricant movers 76 direct the lubricant 48 inward towards axis of rotation 28, with the lubricant circulating and moving through the bearings 64 and 66. Preferably the first rotor lubricated bearing 64 includes an outer race 78 secured to the housing 30 proximate the rotor housing cavity circumferential surface 74 and an inner race 80 secured to the first rotor 38, with the ball bearing moving rolling members 82 allowing the imbalance rotor 38 with inner race 80 to spin faster than housing 30 with outer race 78. Preferably the second rotor lubricated bearing 66 includes an outer race 78 secured to the housing 30 proximate the rotor housing cavity circumferential surface 74 and an inner race 80 secured to the second imbalance rotor 44, with the ball bearing moving rolling members 82 allowing the second imbalance rotor 44 with inner race 80 to spin faster than housing 30 with outer race 78. Preferably the bearing moving rolling members 82 are lubricated in the liquid lubricant 48 constrained against circumferential surface 74, most preferably bathed and submersed in the lubricant. In an embodiment the first and second rotor cavities are substantially completely filled with the liquid lubricant 48. In a preferred embodiment the first and second rotor cavities are partially filled with liquid lubricant 48, preferably such that when housing 30 rotates at helicopter operational rotation frequency 26 the lubricated bearings are lubricated by the liquid lubricant 48 but the rotors are not submerged in the liquid, preferably with the rotors rotating through a non-liquid gas. Preferably the liquid lubricant 48 is sealed inside the rotor housing cavity 34. In a preferred embodiment the electronics housing cavity subsystem 32 is fluidly isolated from rotor cavity subsystem 34, with the lubricant only in rotor cavities 60 and 62.
Preferably the helicopter rotating vibration electronics control system opposingly orients the first imbalance mass concentration and the second imbalance mass concentration at a transitioning rotation speed 53 less than the whole number multiple vibration canceling rotation frequency. As shown in FIG. 20C-D, preferably the invention includes opposingly orienting the first imbalance mass concentration 40 and the second imbalance mass concentration 46 at a transitioning rotation speed 53, different from, and preferably less than the whole number multiple vibration canceling rotation frequency 52, preferably when the transitioning rotation speed is a startup speed less than the whole number multiple vibration canceling rotation frequency with the system starting from a shutdown stop and spinning up towards the whole number multiple vibration canceling rotation frequency or when the transitioning rotation speed is a shutting down speed less that the whole number multiple vibration canceling rotation frequency with the system shutting and slowing down from the full speed whole number multiple vibration canceling rotation frequency down to a shutdown stop. Preferably the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration are oriented opposed such that the vectors 56 and 54 are opposed and cancel each other out while the transitioning rotation speed is no more than ninety percent of the whole number multiple vibration canceling rotation frequency, preferably when the transitioning rotation speed is no more than eighty percent of the whole number multiple vibration canceling rotation frequency, to provide a soft start and stop for the system. When a failure occurs with the rotation of one of the imbalance rotors, such that a soft stop of the system is not achievable, the still operating nonfailed imbalance rotor is positioned and driven to oppose the disturbance force vector 24, with the failed rotor slowing down to a stop, preferably by electromagnetically braking the rotation of the failed rotor. As shown in FIG. 14, in the event of a motor failure, the functioning motor is driven and commanded to the angle of the resultant correction force vector 58 just prior to the motor failure, with the still functioning motor responding by positioning its imbalance rotor eccentric mass concentration to oppose the disturbance force vector 24, preferably with the failed motor's imbalance rotor eccentric mass concentration motion braked to a rest state. Just prior to failure both imbalance rotor eccentric mass concentrations are angularly positioned in order to create a resultant force vector 58 of magnitude and phase (desired phase phi) such that the disturbance force vector 24 is cancelled, upon failure the still functioning motor drives its imbalance rotor eccentric mass concentration to the desired phase phi. Preferably the helicopter rotating vibration electronics control system includes an electromagnetic braking circuit for electromagnetically braking a rotation of the rotors. Preferably the invention includes electromagnetically braking a rotation of the first imbalance rotor or the second imbalance rotor, preferably when the operation of the motor of the imbalance rotor has failed. As shown in FIG. 25G-H, electromagnetic braking circuits 105 preferably complete the electric circuits of electromagnet windings 104 and 106 to electromagnetically brake the spinning imbalance rotor of the failed motor. Preferably the failed rotor/motor is electromagnetically braked by the electromagnetic braking circuit 105 shorting the electromagnet windings 104 and 106, so induced currents produced in the shorted electromagnet windings act to resist permanent magnets 94 moving around the axis of rotation 28. The shorting of the electromagnet windings 104 and 106 completes the electromagnetic braking circuit such that the rotation of the failed imbalance rotor is stopped. Preferably electromagnetically braking the failed rotor by shorting the electromagnet windings 104 and 106, includes utilizing a switch, relay, solid state switch, or FET (Field Effect Transistor), that is preferably open when powered, such that the shorting of the windings with electromagnetic braking circuits 105 is controlled and utilized only for a motor failure.
In an embodiment the invention includes a rotary wing aircraft helicopter rotating vibration control system 20 for a helicopter rotary wing hub 22 having a periodic vibration 24 while rotating at a helicopter operational rotation frequency 26 about a rotary wing axis of rotation 28. The helicopter rotating vibration control system 20 includes a rotary housing 30 centered about and encompassing the rotary wing axis of rotation 28 with the rotary housing 30 rotating at the helicopter operational rotation frequency 26. The rotating rotary housing 30 contains a first coaxial ring motor 36 coaxially centered about the rotary wing axis of rotation 28. The first coaxial ring motor 36 has a first imbalance rotor 38 with a first imbalance rotor eccentric mass concentration 40. The rotating rotary housing 30 contains a second coaxial ring motor 42 coaxially centered about the rotary wing axis of rotation 28 with the second coaxial ring motor having a second imbalance rotor 44 with a second imbalance rotor eccentric mass concentration 46. The rotating rotary housing 30 contains an electronics control system 50 which controls a speed and a phase of the first coaxial ring motor 36 and the second coaxial ring motor 42 such that the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration are directly driven at a whole number multiple vibration canceling rotation frequency 52 greater than the helicopter operational rotation frequency 26 wherein the helicopter rotary wing hub periodic vibration 24 is reduced and minimized. Preferably the rotating rotary housing 30 is comprised of an annular ring shape centered about and encompassing the rotary wing axis of rotation 28. Preferably the rotating rotary housing 30 encompasses the rotor shaft 29, and preferably is attached to and rotates with the helicopter rotary wing hub 22 at the helicopter operational rotation frequency. Preferably the rotary housing 30 has an electronics housing cavity subsystem 32 and an adjacent coaxial rotor housing cavity subsystem 34, preferably the annular ring rotary housing 30 centered about the rotary wing hub axis of rotation 28, with both cavity subsystems encompassing and centered about helicopter rotary wing hub axis of rotation 28. Preferably the first and second coaxial ring motors 36 and 42 are brushless ring motors, and most preferably frameless AC ring motors. Preferably the electronics control system 50 measures the periodic vibration 24, preferably with accelerometers 72, with the electronics control system controlling the speed, relative phase, and absolute phase of the imbalance rotors eccentric mass concentrations to minimize the measured vibration with the rotors gearlessly directly electromagnetically driven at a vibration canceling rotation frequency greater than the helicopter operational rotation frequency. In a preferred embodiment the housing 30 is spinning at 1 per rev (the operational rotation frequency) and the imbalance rotor eccentric mass concentrations 40 and 46 are spinning at 4 per rev, which is 3 per rev relative to housing 30 which is rotating at 1 per rev. The first motor 36 produces a first rotating force 54, the second motor 42 produces a second rotating force 56, which combine to produce a rotating net force vector 58 to cancel the periodic vibration force 24. Preferably the rotary housing 30 confines a fluid liquid lubricant 48. In a preferred embodiment the rotary housing 30 is comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62. Preferably the upper and lower rotor housing cavities are separated so that particle contaminates and spall debris from one imbalance rotor does not contaminate the other imbalance rotor, preferably with upper and lower liquid lubricated cavities liquidly isolated from each other. Preferably the imbalance rotors 38 and 44 have lubricated bearings 64 and 66 for supporting the rotors relative to the housing 30 and providing for the imbalance rotors to spin at a faster rotational speed than the housing 30, preferably with the bearings lubricated by liquid lubricant 48. Preferably the bearings are thin section bearings having bearing dimensions considerably less than the radius of the bearing (h<<r; h=thickness, height, width of bearing much less than radius of bearing). Preferably the housing 30 includes a circumferential wall surface 74 that constrains the lubricant 48 while the housing is rotating at the helicopter operational rotation frequency. Preferably the first rotor lubricated bearing 64 includes an outer race 78 secured to the housing 30 proximate the rotor housing cavity circumferential surface 74 and an inner race 80 secured to the first rotor 38, with the ball bearing moving rolling members 82 allowing the imbalance rotor 38 with inner race 80 to spin faster than housing 30 with outer race 78. Preferably the second rotor lubricated bearing 66 includes an outer race 78 secured to the housing 30 proximate the rotor housing cavity circumferential surface 74 and an inner race 80 secured to the second imbalance rotor 44, with the ball bearing moving rolling members 82 allowing the second imbalance rotor 44 with inner race 80 to spin faster than housing 30 with outer race 78. Preferably the bearing moving rolling members 82 are lubricated in the liquid lubricant 48 constrained against circumferential surface 74, most preferably bathed and submersed in the lubricant. In an embodiment the first and second rotor cavities are substantially completely filled with the liquid lubricant 48. In a preferred embodiment the first and second rotor cavities are partially filled with liquid lubricant 48, preferably such that when housing 30 rotates at helicopter operational rotation frequency 26 the lubricated bearings are lubricated by the liquid lubricant 48 but the rotors are not submerged in the liquid thus minimizing steady-state torque requirements that would arise from viscous drag torque imposed by the liquid lubricant, preferably with the rotors rotating through a non-liquid gas. Preferably the liquid lubricant 48 is sealed inside the rotor housing cavity 34. Preferably the vibration control system housing contains a fault failure detecting health monitoring sensor 84 for monitoring a change in an operational characteristic of the vibration control system, preferably with the health monitoring sensor and health monitoring system incorporated into the electronics control system. The fault failure detecting health monitoring system with sensors 84 measure operational performance characteristics of the vibration control system 20, most preferably operational performance characteristics of the first and second rotors 38 and 44 and their rotation. Preferably the sensors 84 monitor the health of the rotor bearings 64 and 66. In an embodiment the sensors 84 are temperature sensors that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing that may result from the onset of spalling. Preferably the health monitoring system with sensors 84 includes at least two temperature sensors, such as thermocouples, preferably with at least one adjacent the bearing to monitor the bearing temperature. Preferably the health monitoring system utilizes a reference temperature to determine when the bearing temperature is rising above the ambient temperature of the vibration control system 20. The health monitoring system sensors 84 monitor the bearing temperature differences to determine if a bearing is heating up too much in its operation, and when the measured temperature difference exceeds a measured operational performance characteristic limitation, the vibration control system preferably through the electronics control system provides for a correction change in the vibration control system, such as communicating and warning the helicopter user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and failure of the rotation of the rotor. The health monitoring system sensors 84 catches the operation problem at the performance degradation stage, and provides a warning notification to the helicopter operator or maintenance crew, to warn about replacement prior to bearing operation failure. The health monitoring system is preferably linked with the helicopter avionics system, with a warning maintenance signal transmitted to the avionics system and operator. In an embodiment the health monitoring system sensors 84 monitors trends, with the system storing the sensor data and prior to failure of vibration control system operation identifying an approaching failure. In an embodiment the health monitoring system sensors 84 are accelerometers and monitor vibration signal levels at ball pass frequency bands to pickup on a deteriorating bearing race. Health monitoring system sensors 84 may be the accelerometers 72, or preferably separate accelerometer sensors 84 that monitor the ball pass frequency from each time the ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring system senses, monitors, and warns about the vibration control system operation including the motor's 36 and 42 currents, torques, and temperature. Preferably health monitoring system sensors 84 input data into a health monitoring system algorithm, with the algorithm outputting a notification to effect a change/correction to the vibration control system 20 such as service or replacement. In an embodiment the output of the health monitoring system algorithm is a log of collected sensor data that is downloaded and analyzed for performance and operation issues.
In an embodiment the invention includes a method of controlling a periodic vibration 24 of a rotary wing aircraft helicopter with a helicopter rotary wing hub 22, which rotates at an operational rotation frequency 26. The method includes providing an annular ring rotary housing 30 having an electronics housing cavity subsystem 32 and an adjacent coaxial rotor housing cavity subsystem 34. The rotor cavity subsystem 34 contains a first coaxial ring motor 36 coaxially centered about the rotary wing hub axis of rotation 28. The first coaxial ring motor has a first imbalance rotor 38 with a first imbalance rotor eccentric mass concentration 40. The rotor cavity subsystem 34 contains a second coaxial ring motor 42 having a second imbalance rotor 44 with a second imbalance rotor eccentric mass concentration 46, and a lubricant 48. The electronics housing cavity subsystem 32 preferably contains the electronics control system 50 which controls the speed and phase of the first coaxial ring motor 36 and the second coaxial ring motor 42. The method includes securing the annular ring rotary housing 30 to the helicopter rotary wing hub 22 with the annular ring rotary housing rotating at the operational rotation frequency 26. The method includes directly driving the first imbalance rotor 38 and the second imbalance rotor 44 at a whole number multiple vibration canceling rotation frequency 52 greater than the operational rotation frequency 26 while controlling the rotational phase position of the first imbalance rotor eccentric mass concentration and the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector 58 to inhibit the periodic vibration 24. Preferably the lubricant 48 is a liquid lubricant. Preferably the electronics control system 50 measures the periodic vibration 24 and controls the speed, the relative phase and the absolute phase of the first coaxial brushless frameless AC ring motor imbalance rotor 38 and the second coaxial brushless frameless AC ring motor imbalance rotor 44. Preferably the provided housing 30 includes a circumferential surface 74 that constrains the liquid lubricant 48, and the method includes rotating the rotary housing 30 with the helicopter rotary wing hub at the operational rotation frequency 26 with the liquid lubricant collecting at the circumferential surface 74. Preferably the method includes moving the liquid lubricant 48 inward from the circumferential surface 74 towards the axis of rotation 28. Preferably the first rotor 38 has a lubricated bearing 64 for supporting the first rotor relative to the housing 30 and the second rotor 44 has a lubricated bearing 66 for supporting the second rotor relative to the housing 30, and the method includes moving the lubricant collecting at the circumferential surface 74 through lubricated bearings. Preferably the method includes sealing the liquid lubricant 48 in the rotor cavities of housing 30. As shown in an embodiment in FIG. 24E, the first and second imbalance rotors 38 and 44 are coupled together with a plurality of rotor detents 86, preferably detent magnets, such that the rotors can rotate together in the event of one of the motors failing. In an embodiment the method includes magnetically coupling the first rotor with the second rotor, preferably with magnetic detents 86 such that the magnetically coupled rotors slip relative to each other at a prescribed torque, such as with embodiments of FIGS. 24E and 27C. The method preferably includes that in the event of a motor failure the other motor spins both rotors, with the relative position of the two rotor eccentric mass concentrations 40 and 46 varied by controlling acceleration impulses to the working motor to cause the rotors to slip relative to each other. In preferred embodiments the method includes isolating the first rotor 38 in a first rotor upper rotor cavity 60 from the second rotor 44 in a second rotor lower rotor cavity 62. Preferably the upper and lower outer cavities 60 and 62 are separated so that particles, contaminates, and spall debris from one rotor does not contaminate the other, preferably with the upper and lower liquid lubricated outer cavities 60 and 62 liquidly isolated from each other. In an embodiment the housing rotor cavities are substantially completely filled with liquid lubricant 48. In an embodiment the housing rotor cavities are partially filled with liquid lubricant 48, preferably such that when housing 30 rotates at the helicopter operational rotation frequency the lubricated bearings 64 and 66 are lubricated by the liquid lubricant 48 but the rotor is not submerged in the liquid, preferably with the rotors rotating through a non-liquid gas. Preferably the method includes providing at least one health monitoring sensor 84 and monitoring a change in an operational characteristic of the rotors and the vibration control system sensed by the health monitoring sensors. Preferably the health monitoring sensor 84 and its health monitoring system is incorporated into the electronics control system 50. The health monitoring includes measuring operational performance characteristics of the vibration control system 20 with sensors 84, most preferably operational performance characteristics of the first and second rotors 38 and 44 and their rotation, and particularly the performance of bearings 64 and 66. Preferably the method includes monitoring the health of the rotor bearings 64 and 66 with at least one sensor 84. In an embodiment the sensors 84 are temperature sensors that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably the health monitoring system with sensors 84 includes at least two temperature sensors, such as thermocouples, preferably with at least one adjacent the bearing to monitor the bearing temperature. Preferably health monitoring the vibration control system includes utilizing a reference temperature to determine when the bearing temperature is rising above the ambient temperature of the vibration control system 20. The health monitoring system sensors 84 monitor the bearing temperature differences to determine if a bearing is heating up too much in its operation, and when the measured temperature difference exceeds a measured operational performance characteristic limitation, the vibration control system, preferably through the electronics system, provides for a correction change in the vibration control system, such as communicating and warning the helicopter user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and its rotor. The health monitoring system sensors 84 preferably catches the operation problem at the performance degradation stage, and provides a warning notification to the helicopter operator or maintenance crew, to warn about replacement prior to bearing operation failure. The health monitoring system is preferably linked with the helicopter avionics system, with a warning maintenance signal transmitted to the avionics system and operator. In an embodiment the health monitoring method monitors operation trends and stores the sensor data, and prior to failure of vibration control system operation identifies an approaching failure. In an embodiment the provided health monitoring system sensors 84 are accelerometers and the method monitors vibration signal levels at ball pass frequency bands to pickup on a deteriorating bearing race. Health monitoring system sensors 84 may be the accelerometers 72, or preferably separate accelerometer sensors 84 that monitor the ball pass frequency from each time a ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring method includes sensing, monitoring, and warning about the vibration control system operation including the currents, torques, and temperatures of motors 36 and 42. Preferably the health monitoring system sensors 84 input data into a health monitoring system algorithm, with the algorithm outputting a notification to effect a change/correction to the vibration control system 20 such as service or replacement. In an embodiment the health monitoring system algorithm outputs a log of collected sensor data that is downloaded and analyzed for performance and operation issues.
In an embodiment the invention includes a method of making a helicopter rotating hub mounted vibration control system 20 for a helicopter rotary wing hub 22 having a periodic vibration 24 while rotating at a helicopter operational rotation frequency 26. The method includes providing a rotary annular ring housing 30 having an electronics housing cavity subsystem 32 and a rotor housing cavity subsystem 34. The provided rotary annular ring housing 30 provides a structural means for rotating about the axis of rotation 28 at the helicopter operational rotation frequency 26. The housing 30 is centered about the rotary wing hub axis of rotation 28. The rotary housing contains a first coaxial brushless frameless AC ring motor centered about and coaxially with the rotary wing hub axis of rotation 28. The provided first coaxial ring motor has a first rotor 38 with a first imbalance rotor eccentric mass concentration 40. The rotary housing contains a second coaxial brushless frameless AC ring motor centered about and coaxial with the rotary wing hub axis of rotation 28. The second ring motor 42 has a second rotor 44 with a second imbalance rotor eccentric mass concentration 46. Preferably the rotary housing 30 has a circumferential surface 74. Preferably an electronics control system 50 is contained in the rotary annular ring housing 30 with the electronics control system 50 rotating with the housing 30 about the axis of rotation 28 at the helicopter operational rotation frequency 26. The electronics control system 50 measures the periodic vibration and controls a speed, a relative phase and an absolute phase of the first coaxial frameless ring motor and the second coaxial ring motor while rotating with the housing 30 about the axis of rotation 28 at the helicopter operational rotation frequency 26. The method includes sealing a liquid lubricant 48 inside the housing 30, wherein the liquid lubricant 48 collects along the circumferential surface 74 when the housing rotates at the helicopter operational rotation frequency. Preferably the electronics control system is disposed in the housing so that the electronics control system 50 rotates with the housing 30. Preferably providing the housing 30 includes providing a housing 30 with a rotor housing cavity 34 comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62, and the method includes isolating the first rotor 38 in the first rotor upper cavity 60 from the second rotor 44 in the second rotor lower cavity 62. Preferably the method includes providing a health monitoring sensor 84 for monitoring a change in an operational characteristic of the vibration control system and disposing the health monitoring sensor 84 in the rotary housing. Preferably the health monitoring sensor 84 and its health monitoring system is incorporated into the electronics control system 50. The health monitoring sensor 84 measures an operational performance characteristics of the vibration control system 20. Most preferably the sensors 84 are disposed proximate the rotors so the operational performance characteristics of the first and second rotors 38 and 44, and particularly the performance of bearings 64 and 66 are monitored. Preferably the sensors 84 monitor the health of the rotor bearings 64 and 66. In an embodiment the sensors 84 are temperature sensors, preferably thermocouples that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably temperature sensors 84 are disposed adjacent the bearings 64 and 66. Preferably the health monitoring sensors 84 are linked with the electronics control system 50 and the helicopter avionics system such that when a measured characteristic exceeds a measured operational performance characteristic limitation, a warning is transmitted to provide for a correction change in the vibration control system, such as communicating and warning the helicopter user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and its rotor. In an embodiment the provided health monitoring system sensors 84 are accelerometers that monitor the ball pass frequency from each time a ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring sensors are sensors for monitoring and warning about the vibration control system operation including the currents, torques, and temperatures of motors 36 and 42.
In an embodiment the invention includes a vibration control helicopter rotating hub mounted vibration balancer 20, which rotates about a center axis of rotation 28 at an operational rotation frequency 26. Preferably the vibration balancer is detachably attached to the helicopter rotor hub with the balancer rotating with the rotor shaft for controlling problematic helicopter vibrations. As shown in FIG. 25, the vibration balancer 20 is comprised of a first stator 90 having a plurality of electromagnets 92 periodically spaced around the center axis of rotation 28. The vibration balancer 20 is comprised of a first imbalance rotor 38 having an eccentric mass concentration 40 and a plurality of permanent magnets 94 periodically spaced around the center axis of rotation 28. The first imbalance rotor 38 is disposed around and adjacent to the first stator 90 with a bearing 64 providing for rotation of the rotor relative to the housing 30. The vibration balancer 20 is comprised of a second stator 96 having a plurality of electromagnets 98 periodically spaced around the center axis of rotation 28. The vibration balancer 20 is comprised of a second imbalance rotor 44 having an eccentric mass concentration 46 and a plurality of permanent magnets 100 periodically spaced around the center axis of rotation 28. The second imbalance rotor 44 is disposed around and adjacent to the second stator 96 with a bearing 66 providing for rotation of the rotor relative to the housing 30. The permanent magnets 94 are adjacent to and separated from the electromagnets 92 with an air gap 102 wherein the first stator electromagnets 92 directly drive the first imbalance rotor magnets 94 and the first imbalance rotor eccentric mass concentration 40 around the center axis of rotation 28 at a vibration canceling rotation frequency 52 greater than the operational rotation frequency 26. The permanent magnets 100 are adjacent to and separated from the electromagnets 98 with an air gap 102 wherein the second stator electromagnets 98 directly drive the second imbalance rotor magnets 100 and the second imbalance rotor eccentric mass concentration 46 around the center axis of rotation 28 at the vibration canceling rotation frequency 52. Preferably the first and second stators directly drive the first and second imbalance rotors at a vibration canceling rotation frequency 52 that is a whole number multiple of the operational rotation frequency, preferably with the whole number multiple >1, more preferably with the whole number multiple >3 and most preferably with a whole number multiple N where N equals the number of blades on the helicopter. The imbalance rotor eccentric mass concentrations are electromagnetically directly driven with controlled periodically modulated EM fields from the electromagnets which repel/attract the surrounding permanent magnets. The stators directly drive the imbalance rotors with their eccentric mass concentrations, in that the rotors are gearlessly directly driven by the electromagnetic fields generated by the electromagnets without mechanical gears coupling and transmitting the motion. Preferably the housing 30 spins at the operational rotation frequency of 1 per rev and the imbalance rotors are spinning at 4 per rev, which is 3 per rev relative to the housing 30 which is at 1 per rev. The directly driven rotor 38 produces a first rotating force 54, and the second directly driven rotor 44 produces a second rotating force 56, which combine to produce a rotating net force vector 58 to balance out and cancel the periodic rotating vibration force 24. The first imbalance rotor 38 encompasses the first stator 90, and the second imbalance rotor 44 encompasses the second stator 96, with the first imbalance rotor 44 and the first stator 90 adjacent the second imbalance rotor 44 and the second stator 96 stacked and aligned coaxially. In an embodiment the first imbalance rotor eccentric mass concentration 40 is comprised of a first imbalance mass arc and the second imbalance rotor eccentric mass concentration 46 is comprised of a second imbalance mass arc. Preferably the imbalance mass arcs are made of a dense metal such as tungsten. In an embodiment the imbalance mass arcs is incorporated into the structure of the rotor itself, such as with an arc section of the rotor formed from a dense metal structural material and the majority remainder of the rotor formed from a relatively less dense metal structural material. Preferably the rotating vibration balancer includes a liquid lubricant 48 contained by a rotary housing 30, preferably in a lubricated rotor housing cavity subsystem 34. In a preferred embodiment the rotating vibration hub balancer 20 includes an electronics housing cavity subsystem 32 for containing a electronics control system 50, preferably with the electronics housing cavity subsystem 32 unlubricated and fluidly sealed from the lubricated rotor housing cavity subsystem 34. Preferably the electronics control system 50 includes a plurality of control electronics and sensors for controlling the movement of the imbalance rotors 38 and 44. Preferably the stator electromagnet windings are comprised of three phase motor windings. As shown in FIG. 25, preferably the first stator plurality of electromagnets 92 include a first set of electromagnet windings 104 and a parallel adjacent second set of electromagnet windings 106 and the second stator plurality of electromagnets 98 include a first set of electromagnet windings 104 and a parallel adjacent second set of electromagnet windings 106. For example, winding 104 and 106 are wound in a bifilar fashion. Preferably the electronics control system 50 is comprised of a first stator first amplifier 110 and a first stator second amplifier 112, with the first stator first amplifier 110 driving the first set of electromagnet windings 104 and the first stator second amplifier 112 driving the adjacent second set of electromagnet windings 106. Preferably the electronics control system 50 is comprised of a second stator first amplifier 114 and a second stator second amplifier 116, with the second stator first amplifier 114 driving the first set of electromagnet windings 104 and the second stator second amplifier 116 driving the adjacent second set of electromagnet windings 106. Preferably the first amplifiers and the second amplifiers are independently powerable and independently controllable. Preferably each stator (90, 96) has two sets of electromagnetic windings (104 and 106), with each of the sets of winding having its own amplifier (110 and 112) (114 and 116). Preferably the electronics control system includes four amplifiers, with the preferred vibration control system operation utilizing two amplifiers driving each imbalance rotor, with each amplifier and its set of stator electromagnetic windings capable of driving the rotor by itself independent of the other amplifier and its windings. Preferably each amplifier is comprised of a three-phase inverter. Preferably each amplifier is comprised of three switching Amps, as shown in FIG. 25D first stator first amplifier 110 is comprised of its first switching Amp 120, second switching Amp 121, third switching Amp 122. As shown in FIG. 25F first stator second amplifier 112 is comprised of its first switching Amp 123, second switching Amp 124, and third switching Amp 125. As shown in FIG. 25D second stator first amplifier 114 is comprised of its first switching Amp 126, second switching Amp 127, and third switching Amp 128. As shown in FIG. 25F second stator second amplifier 116 is comprised of its first switching Amp 129, second switching Amp 130, and third switching Amp 131. Preferably the rotary housing lubricated rotor housing cavity subsystem 34 has an outer circumferential internal cavity subsystem wall surface 74 with the first imbalance rotor 38 and the second imbalance rotor 44 rotating around the center axis of rotation 28 at the vibration canceling rotation frequency 52 while the outer circumferential internal cavity subsystem wall surface 74 rotates around the center axis of rotation 28 at the operational rotation frequency 26 with centrifugal forces collecting the liquid lubricant 48 along the wall 74. Preferably the first imbalance rotor 38 includes a lubricant mover 76 for moving the lubricant 48, preferably a plurality of protrusions 76 that radially extend out into lubricant 48 held against housing cavity wall surface 74. Preferably the second imbalance rotor 44 includes a lubricant mover 76 for moving the lubricant 48, preferably a plurality of protrusions 76 that radially extend out into lubricant 48 held against housing cavity wall surface 74. Preferably the vibration balancer includes a plurality of lubricant movers 76 for moving the lubricant 48, preferably a plurality of radially extending protrusions 76 that radially extend out into lubricant 48 held against housing cavity wall surface 74. The protrusions form a fluid disturbing wake in the lubricant and cause it to splash into the bearings. In an embodiment the lubricant movers 76 are anchored on the rotors. In an embodiment the lubricant movers 76 are anchored on the ball separators of the bearings 64 and 66. Preferably a first imbalance rotor bearing assembly 64 provides for the rotational movement of the first imbalance rotor 38 relative to the housing 30, and a second imbalance rotor bearing assembly 66 provides for the rotational movement of the second imbalance rotor 44 relative to the housing 30. Preferably the first imbalance rotor bearing assembly 64 has an inner race 80 on the first imbalance rotor 38, an outer race 78 proximate the outer circumferential internal wall 74, and a plurality of rolling members 82 between the inner race 80 and the outer race 78. Preferably the second imbalance rotor bearing assembly 66 has an inner race 80 on the second imbalance rotor 44, an outer race 78 proximate the outer circumferential internal wall 74, and a plurality of rolling members 82 between the inner race 80 and the outer race 78. Preferably the housing cavity, the volume of the lubricant, and the bearing assemblies are sized and oriented such that at the operational rotation frequency 26 the lubricant collects against the wall with the lubricant at least contacting the inside diameter of the outer race. Preferably the operational rotation frequency 26 drives lubricant liquid 48 against the walls 74 and into contact with the rolling members 82. In an embodiment the operational rotation frequency 26 drives lubricant liquid 48 against the walls 74 with the rolling members 82 bathed and preferably partially submerged in the lubricant liquid 48. In an embodiment the housing cavity, the volume of the lubricant, and the bearing assemblies are sized and oriented such that at the operational rotation frequency 26 the lubricant collects against the wall with the lubricant submerging the bearing outer race but not the bearing inner race. In an embodiment the housing cavity, the volume of the lubricant, and the bearing assemblies are sized and oriented such that at the operational rotation frequency 26 the lubricant collects against the wall with the lubricant submerging the bearing outer race but not the bearing ball separators. Preferably the vibration control rotating hub 20 includes an annular ring rotary housing 30 centered about and encompassing the center axis of rotation 28, and more preferably encompassing the rotor shaft 29 and rotating at the operational rotation frequency. Preferably the annular ring rotary housing 30 contains the electronics control system 50, which rotates with the housing around the center axis of rotation 28 with the rotor shaft 29 at the operational rotation frequency. Preferably the vibration control rotating hub 20 includes a health monitoring sensor 84 for monitoring a change in an operational characteristic of the vibration control rotating hub. Preferably the health monitoring sensors 84 and their health monitoring system are incorporated into the electronics control system 50. The health monitoring system sensors 84 measure operational performance characteristics of the vibration control rotating hub system 20, most preferably the operational performance characteristics of the first and second rotors 38 and 44 and their rotation. Preferably the sensors 84 monitor the health of the rotor bearings 64 and 66. In an embodiment the sensors 84 are temperature sensors that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably the health monitoring system with sensors 84 includes at least two temperature sensors, such as thermocouples, preferably with at least one adjacent the bearing to monitor the bearing temperature. Preferably the health monitoring system utilizes a reference temperature to determine when the bearing temperature is rising above the ambient temperature of the vibration control rotating hub system 20. The health monitoring system sensors 84 monitor the bearing temperature differences to determine if a bearing is heating up too much in its operation, and when the measured temperature difference exceeds a measured operational performance characteristic limitation, the vibration control system preferably through the electronics system provides for a correction change in the vibration control rotating hub, such as communicating and warning the helicopter user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and rotation of the rotor. The health monitoring system sensors 84 catches the operation problem at the performance degradation stage, and provides a warning notification to the helicopter operator or maintenance crew, to warn about replacement prior to bearing operation failure. The health monitoring system is preferably linked with the helicopter avionics system, with a warning maintenance signal transmitted to the avionics system and operator. In an embodiment the health monitoring system sensors 84 monitors trends, with the system storing the sensor data and prior to failure of vibration control rotating hub operation identify an approaching failure. In an embodiment the health monitoring system sensors 84 are accelerometers and monitor vibration signal levels at the ball pass frequency bands to pickup on a deteriorating bearing race. Health monitoring system sensors 84 may be the accelerometers 72, or preferably separate accelerometer sensors 84 that monitor the ball pass frequency from each time a bearing ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring system senses, monitors, and warns about the vibration control rotating hub operation including the currents, torques, and temperature of the stators and windings. Preferably the health monitoring system sensors 84 inputs data into a health monitoring system algorithm, with the algorithm outputting a notification to effect a change/correction to the vibration control rotating hub 20 such as service or replacement. In an embodiment the output of the health monitoring system algorithm is a log of collected sensor data that is downloaded and analyzed for performance and operation issues.
In an embodiment the invention includes a method of controlling a periodic vibration of a helicopter with a helicopter rotary wing hub, which rotates about a center axis of rotation at an operational rotation frequency. The method includes providing a first stator 90 having a plurality of electromagnets 92 periodically spaced around the center axis of rotation 28. The method includes providing a first imbalance rotor 38 having an eccentric mass concentration 40 and including a plurality of permanent magnets 94 periodically spaced around the center axis of rotation 28. The method includes disposing and coupling the first imbalance rotor 38 around the first stator 90 such that the first stator electromagnets 92 gearlessly directly drive the first imbalance rotor magnets 94 and the first imbalance rotor eccentric mass concentration 40 around the center axis of rotation. The method includes providing a second stator 96 having a plurality of electromagnets 98 periodically spaced around the center axis of rotation 28. The method includes providing a second imbalance rotor 44 having an eccentric mass concentration 46, and a plurality of magnets 100 periodically spaced around the center axis of rotation 28. The method includes disposing and coupling the second imbalance rotor 44 around the second stator 96 such that the second stator electromagnets 98 directly drive the second imbalance rotor magnets 100 and the second imbalance rotor eccentric mass concentration 46 around the center axis of rotation 28. The method includes directly driving the first rotor 38 and the second rotor 44 at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance rotor eccentric mass concentration 40 and the rotational position of the second imbalance rotor eccentric mass concentration 46 in order to produce a rotating net force vector 58 to inhibit the problematic periodic vibration. The first imbalance rotor encompasses the first stator, and the second imbalance rotor encompasses the second stator, with the first imbalance rotor and the first stator stacked adjacent to the second imbalance rotor and the second stator and aligned coaxially. The rotors are preferably contained in an operational rotation frequency rotary housing 30 spinning at the operational rotation frequency 26, with the imbalance mass concentrations electromagnetically driven at the vibration canceling rotation frequency. The first imbalance rotor eccentric mass concentration produces a first rotating force, and the second imbalance rotor eccentric mass concentration produces a second rotating force, which combine to produce a rotating net force vector to cancel the periodic vibration force. Preferably providing the first stator 90 with a plurality of electromagnets 92 includes providing a first stator 90 with a first set of electromagnet windings 104 and an adjacent parallel second set of electromagnet windings 106. Preferably providing the second stator 96 having a plurality of electromagnets 98 includes providing a second stator 96 with a first set of electromagnet windings 104 and a second set of electromagnet windings 106. Preferably the method includes providing an electronics control system 50, with the electronics control system including a first stator first amplifier 110, a first stator second amplifier 112, a second stator first amplifier 114 and a second stator second amplifier 116. Preferably the first stator first amplifier 110 drives the first stator first set of electromagnet windings 104 and the first stator second amplifier 112 drives the adjacent second set of electromagnet windings 106. Preferably the second stator first amplifier 114 drives the second stator first set of electromagnet windings 104 and the second stator second amplifier 116 drives the adjacent second set of electromagnet windings 106. Preferably in operation two amplifiers drive each imbalance rotor, most preferably with each amplifier and its set of stator electromagnetic windings capable of driving the rotor by itself independent of the other amplifier and its windings. Preferably each amplifier is comprised of three switching Amps. Preferably the method includes driving an imbalance rotor with just one set of windings and one amplifier, preferably when the other set of windings and/or amplifier fails or encounters problems. Preferably the method includes sealing the disposed and coupled first imbalance rotor and first stator and the disposed and coupled second imbalance rotor and second stator in a housing 30 with a liquid lubricant 48. Preferably the housing 30 is comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62, and the method includes isolating the first rotor in the first rotor upper cavity from the second rotor in the second rotor lower cavity, preferably with the upper and lower liquid lubricated cavities liquidly isolated from each other. Preferably the method includes providing a health monitoring sensor 84 and monitoring a change in an operational characteristic of the rotors sensed by the health monitoring sensor. Preferably the health monitoring sensor 84 and its health monitoring system is incorporated into the electronics control system 50. The health monitoring includes measuring operational performance characteristics of the vibration control system 20 with sensors 84, most preferably operational performance characteristics of the first and second rotors 38 and 44 and their rotation, and particularly the performance of bearings 64 and 66. Preferably the method includes monitoring the health of the rotor bearings 64 and 66 with at least one sensor 84. In an embodiment the sensors 84 are temperature sensors that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably the health monitoring system with sensors 84 includes at least two temperature sensors, such as thermocouples, preferably with at least one adjacent the bearing to monitor the bearing temperature. Preferably health monitoring the vibration control system includes utilizing a reference temperature to determine when the bearing temperature is rising above the ambient temperature of the vibration control system 20. The health monitoring system sensors 84 monitor the bearing temperature differences to determine if a bearing is heating up too much in its operation, and when the measured temperature difference exceeds a measured operational performance characteristic limitation, the vibration control system preferably through the electronics system provides for a correction change in the vibration control system, such as communicating and warning the user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and its rotor. The health monitoring system sensors 84 preferably catches the operation problem at the performance degradation stage, and provides a warning notification to the operator or maintenance crew, to warn about replacement prior to bearing operation failure. The health monitoring system is preferably linked with a warning maintenance signal transmitted to the operator. In an embodiment the health monitoring method monitors operation trends and stores the sensor data, and prior to failure of vibration control system operation identifies an approaching failure. In an embodiment the provided health monitoring system sensors 84 are accelerometers and the method monitors vibration signal levels at ball pass frequency bands to pickup on a deteriorating bearing race. Health monitoring system sensors 84 may be the accelerometers 72, or preferably separate accelerometer sensors 84 that monitor the ball pass frequency from each time a ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring method includes sensing, monitoring, and warning about the vibration control system operation including the motor's currents, torques, and temperatures. Preferably the health monitoring system sensors 84 input data into a health monitoring system algorithm, with the algorithm outputting a notification to effect a change/correction to the vibration control system 20 such as service or replacement. In an embodiment the health monitoring system algorithm outputs a log of collected sensor data that is downloaded and analyzed for performance and operation issues.
In an embodiment the invention includes a rotating vibration balancer control system for a rotating machine having an operational rotation frequency. The rotating vibration control system provides for controlling a rotating periodic disturbance vibration force of the rotating machine. The rotating vibration balancer control system rotates about a center axis of rotation 28 at the operational rotation frequency 26. The rotating vibration control system includes a first motor 36 with electromagnets periodically spaced around the center axis of rotation 28, preferably the first motor 36 is a brushless frameless AC ring motor. The balancer includes a first imbalance rotor 38 with a mass concentration 40, with the first imbalance rotor including a plurality of magnets periodically spaced around said center axis of rotation 28. Preferably the plurality of magnets include a plurality of rotor detent magnets 86 periodically spaced along the circumference of the rotor. The first imbalance rotor 38 and the first motor 36 are centered about said axis of rotation 28, with the first imbalance rotor driven by the first motor around the center axis of rotation at a vibration controlling rotation frequency 52 greater than said operational rotation frequency 26. The rotating vibration control system includes a second imbalance rotor 44 having a mass concentration 46, with the second imbalance rotor 44 centered about the axis of rotation 28 with the second imbalance rotor 44 proximate the first imbalance rotor 38 wherein the second imbalance rotor mass concentration 46 is movable relative to the first imbalance rotor in order to produce a rotating balancing net force to minimize and cancel out the periodic vibration force. In an embodiment the second imbalance rotor mass concentration 46 is movable relative to the first imbalance rotor with a second motor 42 that moves the second imbalance rotor 44. In an embodiment such as shown in FIG. 8E, the first and second imbalance rotors 38 and 44 are coupled together with a plurality of rotor detent magnets 86, such that the rotors can rotate together in the event of one of the motors failing. The first rotor is magnetically coupled to the second rotor with the magnetic detents 86 such that the magnetically coupled rotors slip relative to each other at a prescribed torque. The relative position of the two rotor eccentric mass concentrations 40 and 46 can be varied by controlling acceleration impulses to the motor to cause the rotors to slip relative to each other. In an embodiment such as shown in FIG. 27, an electromagnetic coil 200 controllably generates a magnetic field that creates a magnetic circuit between the rotor detent magnets 86 along the circumference of the first and second imbalance rotors 38 and 44 that provides for the relative motion between the first and second rotors. As shown in FIG. 20, the first rotor produces a first rotating force 54 and the second rotor produces a second rotating force 56 which combine to produce a rotating net force vector 58 rotating multiples faster than the operational rotation frequency 26 to balance out the periodic vibration force 24. The invention includes a method of making a rotating vibration control device, which rotates about a center axis of rotation at an operational rotation frequency. The rotating vibration control device is utilized with a rotating machine having a rotating periodic disturbance vibration when rotating at the operational rotation frequency. The method includes providing an annular ring rotary housing 30. Preferably the housing 30 includes an electronics housing cavity subsystem 32 and a rotor housing cavity subsystem 34. Preferably the housing 30 is centered about the hub axis of rotation 28 with the electronics housing cavity subsystem 32 centered about the axis of rotation 28 and the rotor cavity subsystem 34 preferably adjacent and coaxial with the electronics cavity 32. Preferably the method includes providing a first stator 90 having a plurality of electromagnets 92 periodically spaced around the center axis of rotation 28, and providing a first imbalance rotor 38 having an eccentric mass concentration 40 and including a plurality of permanent magnets 94 periodically spaced around the center axis of rotation 28. Preferably the method includes coupling the first imbalance rotor with the first stator such that the first stator electromagnets 92 directly drive the first imbalance rotor magnets 94 and the first imbalance rotor eccentric mass concentration 40 around the center axis of rotation 28. Preferably the method includes providing a second stator 96 having a plurality of electromagnets 98 periodically spaced around the center axis of rotation 28. Preferably the method includes providing a second imbalance rotor 44 having an eccentric mass concentration 46 and including a plurality of magnets 100 periodically spaced around the center axis of rotation 28. Preferably the method includes coupling the second imbalance rotor with the second stator such that the second stator electromagnets 98 directly drive the second imbalance rotor magnets 100 and the second imbalance rotor eccentric mass concentration 46 around the center axis of rotation 28. Preferably the method includes sealing the coupled first imbalance rotor and the first stator and the coupled second imbalance rotor and the second stator in the housing 30, most preferably with a liquid lubricant in the housing with the rotors, wherein the imbalance rotors are directly driven at a vibration canceling rotation frequency greater than the rotating machine operational rotation frequency. Preferably the imbalance rotors are directly driven at a vibration canceling rotation frequency that is a whole number multiple of the rotating machine operational rotation frequency. Preferably the housing 30 is comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62, and the method includes isolating the first rotor 38 in the first rotor upper cavity 60 from the second rotor 44 in the second rotor lower cavity 62. Preferably providing the first stator having a plurality of electromagnets includes providing a first stator 90 with a first set of electromagnet windings 104 and an adjacent parallel second set of electromagnet windings 106 and providing the second stator having a plurality of electromagnets includes providing a second stator 96 with a first set of electromagnet windings 104 and a parallel second set of electromagnet windings 106. Preferably the method includes providing an electronics control system 50, with the electronics control system including a first stator first amplifier 110, a first stator second amplifier 112, a second stator first amplifier 114 and a second stator second amplifier 116, with the first stator first amplifier 110 driving the first stator first set of electromagnet windings 104, the first stator second amplifier 112 driving the parallel first stator second set of electromagnet windings 106, and with the second stator first amplifier 114 driving the second stator first set of electromagnet windings 104 and the second stator second amplifier 116 driving the parallel second set of electromagnet windings 106. Preferably the electronics control system 50 rotates about the center axis of rotation 28 along with the housing 30 at the operational rotation frequency 26. Preferably each stator has two sets of windings and connected amplifiers, with each set capable of driving the imbalance, with preferred operation having two amplifiers/two sets of windings driving each rotor, with a rotor driven with just one set of windings when an operation problem is encountered with the other set of windings and its amplifier. The method preferably includes providing a health monitoring sensor 84 for monitoring a change in an operational characteristic of the rotating machine and disposing the health monitoring sensor in the rotary housing 30. The method preferably includes providing the health monitoring sensor 84 and preferably incorporating the sensor 84 into the electronics control system 50 to provide a health monitoring sensor system. The health monitoring sensor 84 measures an operational performance characteristic of the vibration control system 20. Most preferably the sensors 84 are disposed proximate the rotors so the operational performance characteristics of the first and second rotors 38 and 44, and particularly the performance of bearings 64 and 66 are monitored. Preferably the sensors 84 monitor the health of the rotor bearings 64 and 66. In an embodiment the sensors 84 are temperature sensors, preferably thermocouples that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably temperature sensors 84 are disposed adjacent the bearings 64 and 66. Preferably the health monitoring sensors 84 are linked with the electronics control system 50 such that when a measured characteristic exceeds a measured operational performance characteristic limitation, a warning is transmitted to provide for a correction change in the vibration control system, such as communicating and warning the rotating machine user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and its rotor. In an embodiment the provided health monitoring system sensors 84 are accelerometers that monitor the ball pass frequency from each time a ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring sensors are sensors for monitoring and warning about the vibration control system operation such as operational currents, torques, and temperatures.
In an embodiment the invention includes a method of making a helicopter rotating vibration balancer, which rotates about a center axis of rotation at an operational rotation frequency. The method includes providing an annular ring rotary housing 30. Preferably the housing 30 includes an electronics housing cavity subsystem 32 and a rotor housing cavity subsystem 34. Preferably the housing 30 is centered about the rotary wing hub axis of rotation 28 with the electronics housing cavity subsystem 32 centered about axis of rotation 28 and the rotor cavity subsystem 34 adjacent and coaxial with the electronics cavity 32. Preferably the method includes providing a first stator 90 having a plurality of electromagnets 92 periodically spaced around the center axis of rotation 28, and providing a first imbalance rotor 38 having an eccentric mass concentration 40 and including a plurality of permanent magnets 94 periodically spaced around the center axis of rotation 28. Preferably the method includes coupling the first imbalance rotor around first stator such that the first stator electromagnets 92 directly drive the first imbalance rotor magnets 94 and the first imbalance rotor eccentric mass concentration 40 around the center axis of rotation 28. Preferably the method includes providing a second stator 96 having a plurality of electromagnets 98 periodically spaced around the center axis of rotation 28. Preferably the method includes providing a second imbalance rotor 44 having an eccentric mass concentration 46 and including a plurality of magnets 100 periodically spaced around the center axis of rotation 28. Preferably the method includes coupling the second imbalance rotor around the second stator such that the second stator electromagnets 98 directly drive the second imbalance rotor magnets 100 and the second imbalance rotor eccentric mass concentration 46 around the center axis of rotation 28. Preferably the method includes sealing the coupled first imbalance rotor and the first stator and the coupled second imbalance rotor and the second stator in the housing 30, most preferably with a liquid lubricant in the housing with the rotors. Preferably the housing 30 is comprised of a first rotor upper cavity 60 and a second rotor lower cavity 62, and the method includes isolating the first rotor 38 in the first rotor upper cavity 60 from the second rotor 44 in the second rotor lower cavity 62. Preferably providing the first stator having a plurality of electromagnets includes providing a first stator 90 with a first set of electromagnet windings 104 and an adjacent parallel second set of electromagnet windings 106 and providing the second stator having a plurality of electromagnets includes providing a second stator 96 with a first set of electromagnet windings 104 and a parallel second set of electromagnet windings 106. Preferably the method includes providing an electronics control system 50, with the electronics control system including a first stator first amplifier 110, a first stator second amplifier 112, a second stator first amplifier 114 and a second stator second amplifier 116, with the first stator first amplifier 110 driving the first stator first set of electromagnet windings 104, the first stator second amplifier 112 driving the parallel first stator second set of electromagnet windings 106, and with the second stator first amplifier 114 driving the second stator first set of electromagnet windings 104 and the second stator second amplifier 116 driving the parallel second set of electromagnet windings 106. Preferably the electronics control system 50 rotates about the center axis of rotation 28 along with the housing 30 at the operational rotation frequency 26. Preferably each stator has two sets of windings and connected amplifiers, with each set capable of driving the imbalance, with preferred operation of the helicopter rotating hub 20 having two amplifiers/two sets of windings driving each rotor, with a rotor driven with just one set of windings when a operation problem is encountered with the other set of windings and its amplifier. The method preferably includes providing a health monitoring sensor 84 for monitoring a change in an operational characteristic of the helicopter rotating hub and disposing the health monitoring sensor in the rotary housing 30. The method preferably includes providing the health monitoring sensor 84 and preferably incorporating the sensor 84 into the electronics control system 50 to provide a health monitoring sensor system. The health monitoring sensor 84 measures an operational performance characteristic of the vibration control system 20. Most preferably the sensors 84 are disposed proximate the rotors so the operational performance characteristics of the first and second rotors 38 and 44, and particularly the performance of bearings 64 and 66 are monitored. Preferably the sensors 84 monitor the health of the rotor bearings 64 and 66. In an embodiment the sensors 84 are temperature sensors, preferably thermocouples that monitor the temperature of the bearings for a change in bearing operation temperature that signals a bearing heat up and degradation in the operation of the bearing. Preferably temperature sensors 84 are disposed adjacent the bearings 64 and 66. Preferably the health monitoring sensors 84 are linked with the electronics control system 50 and the helicopter avionics system such that when a measured characteristic exceeds a measured operational performance characteristic limitation, a warning is transmitted to provide for a correction change in the vibration control system, such as communicating and warning the helicopter user and maintainers that bearing maintenance and/or replacement should be performed so that the bearing operation is corrected prior to failure of the bearing and its rotor. In an embodiment the provided health monitoring system sensors 84 accelerometers that monitor the ball pass frequency from each time a ball rolls over a bearing race problem spot and makes a vibration. Additionally in embodiments the health monitoring sensors are sensors for monitoring and warning about the vibration control system operation such as operational currents, torques, and temperatures.
In an embodiment the invention includes a helicopter rotating vibration control system for a helicopter with a rotating wing assembly having a periodic vibration while rotating at a helicopter operational rotation frequency about a rotary wing axis of rotation. Preferably the helicopter rotating vibration control system includes a rotary housing, the housing centered about and encompassing the rotary wing axis of rotation and rotating with the helicopter rotary wing hub at the helicopter operational rotation frequency, the housing containing a first coaxial ring motor coaxially centered about the rotary wing axis of rotation, the first coaxial ring motor having a first rotor with a first imbalance mass concentration, the housing containing a second coaxial ring motor coaxially centered about the rotary wing axis of rotation, the second coaxial ring motor having a second rotor with a second imbalance mass concentration. Preferably the housing contains the electronics control system with program instructions which control a speed and a phase of the first coaxial ring motor and the second coaxial ring motor such that the first imbalance mass concentration and the second imbalance mass concentration are directly driven at a whole number multiple vibration canceling rotation frequency greater than the helicopter operational rotation frequency wherein the helicopter periodic vibration is reduced. Preferably the system includes a health monitoring sensor for monitoring a change in an operational characteristic of the vibration control system. Preferably the system includes a fault mode control protocol for controlling a rotation of the rotors during a failure of the rotating assembly vibration control system, preferably with an electromagnetic braking circuit for electromagnetically braking a rotation of the rotors. Preferably the system includes a soft start stop control subsystem with program instructions including a start stop protocol, the soft start stop control subsystem providing commands to the motor control loop to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration. Preferably the system opposingly orients the first imbalance mass concentration and the second imbalance mass concentration at a transitioning rotation speed, the transitioning rotation speed preferably less than the whole number multiple vibration canceling rotation frequency during starting and stopping of the helicopter rotor system and the vibration control system.
In an embodiment the invention includes method of controlling a periodic vibration of an aircraft with a rotary hub which rotates at an operational rotation frequency. The method including providing an annular ring housing having a rotor housing cavity subsystem, the rotor cavity subsystem containing a first motor having a first rotor with a first imbalance mass concentration, a second motor having a second rotor with a second imbalance mass concentration, and preferably securing the annular ring housing to the rotary hub with the annular ring housing rotating at the operational rotation frequency with the rotary hub. The method includes driving the first rotor and the second rotor with motor control commands at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration. Preferably including directly driving the first rotor and the second rotor at a whole number multiple vibration canceling rotation frequency greater than the operational rotation frequency while controlling the rotational position of the first imbalance mass concentration and the second imbalance mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration. Preferably the method includes providing a health monitoring sensor and monitoring a change in an operational characteristic sensed by the health monitoring sensor. Preferably the method includes providing a soft start stop control subsystem, the soft start stop control subsystem providing commands to the motor control loop to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration. Preferably the method includes providing a fault mode control protocol for controlling a rotation of the rotors during a failure of the rotating assembly vibration control system. Preferably the method includes electromagnetically braking a rotation of the rotors. Preferably the method includes opposingly orienting the first imbalance mass concentration and the second imbalance mass concentration at a transitioning rotation speed less than the whole number multiple vibration canceling rotation frequency.
In an embodiment the invention includes rotating vibration control system which rotates about a center axis of rotation at an operational rotation frequency. The rotating vibration control system preferably comprised of a first stator having a plurality of electromagnets, the electromagnets periodically spaced around a center axis of rotation, a first imbalance rotor having a mass concentration, the first imbalance rotor including a plurality of magnets periodically spaced around the center axis of rotation, the first imbalance rotor adjacent the first stator, and a second stator having a plurality of electromagnets, the electromagnets periodically spaced around a center axis of rotation, a second imbalance rotor having a having a mass concentration, the second imbalance rotor including a plurality of magnets periodically spaced around the center axis of rotation, the second imbalance rotor adjacent the second stator. The rotating vibration control system preferably comprised of a vibration sensor accelerometer for producing a vibration sensor signal, an outer vibration control loop for providing motor control commands to rotate the first rotor and the second rotor to minimize the vibration sensor signal. Preferably the first stator electromagnets directly drive the first imbalance rotor magnets and the first imbalance rotor mass concentration around the center axis of rotation at a vibration controlling rotation frequency greater than the operational rotation frequency, and the second stator electromagnets directly drive the second imbalance rotor magnets and the second imbalance rotor mass concentration around the center axis of rotation at the vibration controlling rotation frequency. Preferably the system including a first stator first amplifier and a first stator second amplifier, and the first stator plurality of electromagnets includes a first set of electromagnet windings and a second set of electromagnet windings with the first stator first amplifier driving the first set of electromagnet windings and the first stator second amplifier driving the adjacent second set of electromagnet windings. Preferably the system including a second stator first amplifier and a second stator second amplifier, and the second stator plurality of electromagnets includes a first set of electromagnet windings and a second set of electromagnet windings with the second stator first amplifier driving the first set of electromagnet windings and the second stator second amplifier driving the adjacent second set of electromagnet windings. Preferably the system includes a soft start stop control subsystem (electronic computer program instructions, soft start/stop protocol), the soft start/stop control subsystem providing commands to the motor control loop to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration. Preferably the system including a fault mode control protocol for controlling a rotation of the rotors during a failure of the rotating assembly vibration control system.
In an embodiment the invention includes a method of controlling a periodic vibration of a rotating assembly which rotates about a center axis of rotation at an operational rotation frequency. The method including: providing a first stator having a plurality of electromagnets, the electromagnets periodically spaced around a center axis of rotation, and a first imbalance rotor, the first imbalance rotor having an eccentric mass concentration, the first imbalance rotor including a plurality of magnets periodically spaced around the center axis of rotation, providing a second stator having a plurality of electromagnets, the electromagnets periodically spaced around a center axis of rotation, and a second imbalance rotor, the second imbalance rotor having an eccentric mass concentration, the second imbalance rotor including a plurality of magnets periodically spaced around the center axis of rotation, and providing computer readable program instructions to control the rotation of the first rotor and the rotation of the second rotor to minimize the periodic vibration. Preferably the program instructions command and drive the first rotor and the second rotor at a whole number multiple vibration controlling rotation frequency greater than the operational rotation frequency while controlling a rotational position of the first imbalance rotor eccentric mass concentration and a rotational position of the second imbalance rotor eccentric mass concentration in order to produce a rotating net force vector to inhibit the periodic vibration. Preferably the method includes providing an electronics control system, with the electronic control system including a processing unit. Preferably the electronic control system includes a first stator first amplifier, a first stator second amplifier, a second stator first amplifier and a second stator second amplifier. Preferably the system includes the first stator having a plurality of electromagnets with a first set of electromagnet windings and a second set of electromagnet windings, with the first stator first amplifier driving the first set of electromagnet windings and the first stator second amplifier driving the second set of electromagnet windings. Preferably the system includes the second stator having a plurality of electromagnets with a first set of electromagnet windings and a second set of electromagnet windings, with the second stator first amplifier driving the first set of electromagnet windings and the second stator second amplifier driving the second set of electromagnet windings. Preferably the method includes providing a soft start stop control subsystem (program instructions, start stop protocol), the soft start stop control subsystem providing commands to the motor control loop to opposingly orient the first imbalance mass concentration relative to the second imbalance mass concentration. Preferably the method includes providing a fault mode control protocol for controlling a rotation of the rotors during a failure of the rotating assembly vibration control system.
In an embodiment the invention includes a rotating vibration control system which rotates about a center axis of rotation at an operational rotation frequency, the rotating vibration control system for balancing out a periodic vibration force, the rotating vibration control system comprised of a first motor having a plurality of electromagnets, the electromagnets periodically spaced around a center axis of rotation, a first imbalance rotor having a mass concentration, the first imbalance rotor including a plurality of magnets periodically spaced around the center axis of rotation, the first imbalance rotor and the first motor centered about the axis of rotation, the first imbalance rotor driven by the first motor around the center axis of rotation at a vibration controlling rotation frequency, preferably greater than the operational rotation frequency, and a second imbalance rotor, the second imbalance rotor having a mass concentration, the second imbalance rotor centered about the axis of rotation with the second imbalance rotor proximate the first imbalance rotor, the second imbalance rotor mass concentration movable relative to the first imbalance rotor mass concentration. The invention includes a vibration sensor accelerometer for producing a vibration sensor signal, and a outer vibration control loop for providing commands to control the rotation of the first rotor and the rotation of the second rotor to minimize the vibration sensor signal. The invention preferably including commands to control the position of the second imbalance rotor mass concentration relative to the first imbalance rotor mass concentration in order to produce a rotating balancing net force to cancel out the periodic vibration force, preferably with a soft start/stop. The invention preferably including a fault mode control protocol.
It will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the spirit and scope of the invention. Thus, it is intended that the invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. It is intended that the scope of differing terms or phrases in the claims may be fulfilled by the same or different structure(s) or step(s).

## Claims

1. A rotating assembly vibration control system for a rotating assembly having a periodic vibration while rotating at an operational rotation frequency,
said rotating assembly vibration control system including a first imbalance mass concentration rotor and a second imbalance mass concentration rotor, wherein said first imbalance mass concentration rotor and said second imbalance mass concentration rotor are rotated at a whole number multiple vibration canceling rotation frequency greater than said rotating assembly operational rotation frequency while controlling the rotational position of said first imbalance mass concentration and said second imbalance mass concentration to produce a rotating net force vector to inhibit said periodic vibration,
and said first imbalance mass concentration is opposingly oriented relative to said second imbalance mass concentration during a starting stopping rotation speed less than said whole number multiple vibration canceling rotation frequency.

2. A rotating assembly vibration control system as claimed in claim 1, said rotating assembly vibration control system including a fault mode control protocol for controlling a rotation of said rotors during a sensed failure of the rotating assembly vibration control system.

3. A rotating assembly vibration control system as claimed in claim 2, said rotating assembly vibration control system including motor control servo subsystem to position said first rotor to track a first rotor command (R1_phi) and to position said second rotor to track a second rotor command (R2_phi).

4. A rotating assembly vibration control system as claimed in claim 2, wherein said fault mode control protocol includes a failure detecting sensor for detecting a first rotor failure.

5. A rotating assembly vibration control system as claimed in claim 2, wherein said fault mode control protocol includes a failure detecting sensor for detecting a second rotor failure.

6. A rotating assembly vibration control system as claimed in claim 4, wherein said first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and said second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to said first rotor failure, and upon detecting said first rotor failure said second rotor is commanded to a resultant phase (F_phase) position.

7. A rotating assembly vibration control system as claimed in claim 5 wherein said first rotor is commanded to a prefailure first rotor (R1_phi) command angular position and said second rotor is commanded to a prefailure second rotor (R2_phi) command angular position prior to said second rotor failure, and upon detecting said second rotor failure said first rotor is commanded to a resultant phase (F_phase) position.

8. A rotating assembly vibration control system as claimed in claim 1, said system including a failure detecting sensor for detecting a rotor failure.

9. A method of controlling aircraft vibrations, said method including providing a rotating assembly vibration control system for a rotating assembly having a periodic vibration while rotating at an operational rotation frequency, said rotating vibration control system including a first imbalance mass concentration rotor and a second imbalance mass concentration rotor,
driving said first imbalance mass concentration rotor and said second imbalance mass concentration rotor at a vibration canceling rotation frequency while controlling the rotational position of said first imbalance mass concentration and said second imbalance mass concentration to produce a net force vector to inhibit a vibration,
opposingly orienting said first imbalance mass concentration relative to said second imbalance mass concentration during a transitioning rotation speed.

10. A method as claimed in claim 9, said method including monitoring a tachometer input signal and maintaining an opposing orientation of said first imbalance mass concentration and said second imbalance mass concentration unless said rotors are driving in sync with said tachometer input signal.

11. A method as claimed in claim 9, said method including controlling a rotation of said rotors during a sensed failure of the rotating vibration control system.

12. A method as claimed in claim 10, said method including positioning said first rotor to track a first rotor command (R1_phi) and positioning said second rotor to track a second rotor command (R2_phi).

13. A method as claimed in claim 11, said method including monitoring a sensor signal and detecting a first rotor failure.

14. A method as claimed in claim 12, said method including monitoring a sensor signal and detecting a second rotor failure.

15. A method as claimed in claim 13, said method including commanding said first rotor to a prefailure first rotor (R1_phi) command angular position and commanding said second rotor to a prefailure second rotor (R2_phi) command angular position prior to said first rotor failure, and upon detecting said first rotor failure commanding said second rotor to a resultant phase (F_phase) position.

16. A method as claimed in claim 14, said method including commanding said first rotor to a prefailure first rotor (R1_phi) command angular position and commanding said second rotor to a prefailure second rotor (R2_phi) command angular position prior to said second rotor failure, and upon detecting said second rotor failure commanding said first rotor to a resultant phase (F_phase) position.

17. A method as claimed in claim 9, said method including monitoring a sensor signal and detecting a failure.

18. An aircraft rotating vibration control system for an aircraft assembly having an operational vibration, said aircraft vibration control system including:
a first motor having a first rotor with a first imbalance mass concentration, said first motor driving a rotation of said first rotor,
a second motor having a second rotor with a second imbalance mass concentration, said second motor driving a rotation of said second rotor,
a first vibration sensor for producing a first vibration sensor signal,
a second vibration sensor for producing a second vibration sensor signal,
a first rotor rotational position sensor for producing a first rotor rotational position signal,
a second rotor rotational position sensor for producing a second rotor rotational position signal,
a motor control loop for controlling the rotation of said first rotor and the rotation of said second rotor with an input from said first rotor rotational position signal and with an input from said second rotor rotational position signal,

a vibration control loop for providing commands to the motor control loop to minimize an input from said first vibration sensor signal and an input from said second vibration sensor signal, and a soft start stop control subsystem, said soft start stop control subsystem opposingly orienting said first imbalance mass concentration relative to said second imbalance mass concentration.

19. A system as claimed in claim 18, wherein said soft start stop control subsystem opposingly orients said first imbalance mass concentration relative to said second imbalance mass concentration during a rotation speed ramp up.

20. A system as claimed in claim 18, wherein said soft start stop control subsystem opposingly orients said first imbalance mass concentration relative to said second imbalance mass concentration during a rotation speed ramp down.

21. A system as claimed in claim 18, wherein said vibration control system rotates said first rotor and said second rotor at a whole number multiple vibration canceling rotation frequency greater than an operational rotation frequency of said assembly producing said operational vibration.

22. A system as claimed in claim 18, wherein said soft start stop control subsystem opposingly orients said first imbalance mass concentration relative to said second imbalance mass concentration during a starting stopping rotation speed less than said whole number multiple vibration canceling rotation frequency.