MACHINE CONTROL SYSTEMS

Abstract: Methods and apparatus for enhancing operations of manufacturing machines, including armature winding machines, utilizing a programmable motion controller and a servo motor and, in different embodiments, an industrial computer or a programmable logic controller. Synchronous parallel sequencing by which one machine operation is initiated before the preceding machine operation is completed is used to increase production speeds of manufacturing machines. Armature winding machines are operated to have S-curve acceleration and deceleration ramps which may be independent of one another.

Description: MACHINE CONTROL SYSTEMS BACKGROUND 1. Field of Invention This invention relates to machine control systems generally applicable to the automatic control of manufacturing machines. Aspects of this invention are particularly useful for controlling the operation of machines for manufacturing armatures for dynamoelectric devices, particularly electric motor armatures, and for machines for manufacturing stators for dynamoelelectric devices. 2. Cross-Reference to Related Application This application claims the benefit of copending U. S. Provisional Application No. 60/065,007, filed November 10, 1997. 3. Incorporation by Reference U.S. Patent No. 4,163,931, issued to David R. Seitz and Mark T. Heaton on August 7, 1979, and U.S. Patent No. 5,470,025, issued to Alvin C. Banner and Mark T. Heaton on November 28, 1995, are hereby incorporated by reference herein. Also incorporated by reference herein are a brochure titled EXACTROL Electronic Wire Tensioner published before 1987 by The Globe Tool and Engineering Company, Dayton, Ohio, USA, and a copy of a brochure titled EXACTROL-FM Electronic Wire Tensioning System with Force Measurement , published 1986 by Statomat-Globe, Inc., Dayton, Ohio, USA. In addition. the outside and inside front and back cover pages and pages 5 through 9 of a brochure titled Programmable Multi-Axis Controller published 1994 by Delta Tau Data Systems, Northridge, California, USA, are incorporated by reference herein. Further incorporated herein are the cover page and pages 3-188 through 3-196 of the August 1996 PMAC Users Manual and the cover page and pages 6- 121, 7-60, 7-75 and 7-76 of the August 1996 PMAC Software Reference, both published by Delta Tau Data Systems, Incorporated, Northridge, California, USA. A copy of each of the documents mentioned above is submitted herewith. ] 4. Prior Art and Other Considerations Control systems for manufacturing machines, including armature winding machines and stator winding machines, are typically event driven and, to a lesser extent, driven by timers. Event driven control systems commonly initiate an operation following detection of the completion of a prior operation. Thus, a limit switch may be placed under pressure, or an encoder may indicate that a given rotary position has been reached, whereupon a signal is sent to the machine controller that a certain event has been completed. The controller then initiates the next machine operation. An example of machine controls of this type is disclosed in the aforementioned Seitz and Heaton patent no. 4,163,931. Although machine control systems have reached a high level of sophistication and control speeds, there is an ever-present need for further increases in control speeds so that mass-produced parts can be manufactured in less time. The Seitz and Heaton patent no. 4,163,931 discusses the ramping up and down, or acceleration and deceleration, of motor speeds used in armature winding machines. Machine controllers used in armature winding machines are capable of ramping up and down to or from a given speed with the same ramping slope and time. Armature winding machines often do not need a ramping down slope and time as gradual as the ramping up time. Accordingly, the machine control circuitry commonly used to control armature winders unnecessarily increases the overall manufacturing cycle because of the delays occasioned by the longer than necessary ramp down times. The known acceleration and deceleration ramps of the motors used to drive the wire-guiding fliers of armature winders are essentially straight lines, and are necessarily sufficiently gradual to enable a start-up of the fliers without breaking the wires which are wound into coils by the fliers. Armature winding machines are usually provided with wire tensioning devices that can be adjusted during each cycle of the operation of the armature winders. The aforementioned EXACTROL and EXACTROL-FM brochures describe wire tensioning systems that can be used to control the resistance to movement of wire through a wire dereeler system. The tensioning systems use a magnetic brake that can be used to control the resistance to the movements of a dancer arm, such as the dancer arm 30 shown in the aforesaid Banner and Heaton patent no. 5,470,025. Changes in tension resulting from the uses of variable tension devices occur in abrupt steps so that the wire is often unavoidably subject to abrupt changes in tensions that can jerk the wire and may occasionally result in wire breakage and consequent machine downtime. SUMMARY An object of one aspect of this invention is to provide for flier rotation drive motor and armature or other workpiece indexing drive motor acceleration ramps to follow an S-curve rather than the prior art constant, straight-line acceleration slope. A related object is to provide for flier rotation and an armature or other workpiece indexing deceleration ramps to follow an S-curve rather than the constant, straight-line slopes of the prior art. An object in another aspect of this invention is to decrease the changes in wire tension experienced by the wires used to form the coils of armature winding machines, and thereby minimize the sudden jerks that such wires are subjected to in conventional armature winding machines. In another aspect of this invention, an object is to have deceleration ramps of the rotation of the fliers of armature winding machines during the winding of coils which deceleration ramps are adjustably different from their corresponding acceleration ramps. In still another aspect of this invention, an object is to provide a machine control system for a manufacturing machine in which the initiation of a subsequent operation is triggered by a known position in the operating cycle of a precedent operation as determined by a digital signal processor operating in conjunction with the CPU of a machine controller. A related object of this invention is to reduce the times needed to complete cycles of manufacturing operations by initiating a subsequent operation as a precedent operating cycle is nearing completion. Precious seconds or fractions of seconds can be saved by the implementation of this object. An analogy can be drawn between a relay swimming race and a relay foot race. In a relay swimming race, the first swimmer must touch the wall of the swimming pool before the next swimmer on the same team can jump into the water. This is akin to the event driven machine control. In contrast, in a relay foot race, the second runner runs alongside the first runner so that the second runner is up to speed before the first runner completes the first section of the race. Likewise, it is desired in accordance with this invention that, with regard to any two successive machine operations, when the first operation is nearing, but has not reached, the completion of its operating cycle, the second operation begins its operating cycle. Other objects and advantages will become apparent from the following description of the drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a first embodiment of a machine control system in accordance with this invention used for controlling the operations of the fliers and the armature rotator of an armature winding machine. FIG. 2 is a schematic diagram of a second embodiment of a machine control system in accordance with this invention used for controlling the operations of the fliers and the armature rotator of an armature winding machine. FIG. 3 is a schematic diagram of a third embodiment of a machine control system in accordance with this invention used for controlling the operations of the fliers and the armature rotator of an armature winding machine. FIG. 4 is an elevational view of a wire dereeler for an armature winding machine employing a capstan pulley of the type discussed in the EXACTROL and the EXACTROL-FM brochures. FIG. 5 is a diagram illustrating an S-curve winding velocity profile. FIG. 6 is a diagram illustrating a winding velocity profile having independent acceleration and deceleration ramps with S-curve profiles. FIG. 7 is a diagram illustrating synchronous parallel sequencing, showing the velocity profile of the operation of a winding machine flier and the point in the velocity profile in which the retraction of a commutator shield is initiated. DETAILED DESCRIPTION OF THE DRAWINGS In one aspect, this invention provides S-shaped velocity profiles for the fliers of armature winding machines, such as shown in FIG. 5. To obtain an S-shaped curve velocity profile, a motion controller, preferably a PMAC-Lite Motion Controller shown on page 2 of the aforesaid Delta Tau Systems brochure, can be used along with an industrial computer. Use of an S-curve velocity profile provides advantages in cycle time and can be used to reduce changes in wire tension. Whether or not an S-shaped velocity profile is used, the velocity and position information obtained with the computer and the digital signal processor with feedback as diagrammed in FIG. 1 enables the ability to have two successive operations run together for short intervals of time, and thereby reduce the cycle time of many manufacturing machines, including armature winders, stator winders, and manufacturing machines used in fields related and unrelated to motor manufacturing or coil winding. This is referred to herein as "synchronous parallel sequencing." The overlapping operations of successive machine operations is diagrammatically shown in FIG. 7. Synchronous parallel sequencing can advantageously be used to control the operations of magnetic brakes or other electrically-responsive devices used to control wire tension in armature winding machines. Thus, rather than change tension settings based on time or based on the completion of a flier operation, the tension settings can be initiated based on the known velocity, position, and instantaneous acceleration during an operating cycle of a flier drive motor communicated from the digital signal processor to the CPU of the machine controller. Tension changes can be made to coincide precisely with the event requiring a tension change rather than following the event. Various system configurations may be used to obtain the aforementioned operations. Three variations are shown respectively in FIGS. 1, 2 and 3. The system of FIG. 1 includes a Delta Tau Data Systems Programmable Multi-Axis Controller (PMAC) digital signal processor (DSP) based servo motion controller, servo motor with feedback, and industrial computer controls package. The Delta-Tau PMAC is used in a command/response mode, hosted by the industrial computer controls package. The industrial computer issues motion commands while controlling the sequential functionality of the system. The system of FIG. 2 includes a Delta Tau Programmable Multi-Axis Controller (PMAC) digital signal processor (DSP) based servo motion controller and a servo motor with feedback. The Delta Tau PMAC in this embodiment controls both the motion control and sequential functionality of the machine. Optionally, a user interface may be connected to provide diagnostics and user parameter configuration. In FIG. 3, the system includes a servo motor controller, servo motor with feedback, and a programmable logic controller (PLC) based controls package. The servo motor controller is used in a command/response mode, hosted by the programmable logic controller (PLC). The programmable logic controller (PLC) issues motion commands while controlling the sequential functionality of the system. These system configurations can be used as discussed in the following examples. Example 1 - "S"-Curve Acceleration And Deceleration S -Curve acceleration and deceleration control of the flier arms during the armature winding process can be accomplished by implementing one of the hardware profiles shown in FIGS. 1, 2 and 3. The motion profile is then programmed so that some or all of the acceleration phase of the wind utilizes an S , by using the Delta-Tau Programmable Multi-Axis Controller (PMAC) TS instruction ( Set S-Curve Acceleration Time instruction) . This Example 1 illustrates a parameterized winding program, which incorporates the use of S curve acceleration and deceleration. In this example, the parameters entered include 75 turns with a peak velocity of 3500 RPM, using an acceleration and deceleration time of 750 milliseconds, with 375 milliseconds at both the beginning and end of the total acceleration time. As shown by the winding profile of FIG. 5, a winding velocity profile is obtained in which the acceleration and deceleration is S-shaped and completely smooth. The result is a reduction in the instantaneous forces on the wire during the acceleration and deceleration phase of the wind. These forces occur primarily due to the acceleration, which is the rate change of velocity per unit time (1st derivative of velocity) , and impulse, which is the rate change of acceleration per unit time (2nd derivative of velocity) . To obtain the illustrated S -curve acceleration and deceleration of FIG. 5, the PMAC is given the following instructions: * Program (Parameterized) • CLOSE DELETE GATHER OPEN PROG 2 CLEAR LINEAR ABS TA(P150) TS(P151) F(P152) X(P153) DWELL 0 P2=0 CLOSE ; ** End of Upload ** * Parameters P150=750 P151=375 P152=3500 P153=75.0 Example 2 - Independent Acceleration /Deceleration In a typical armature winding application, the "S"-curve acceleration and deceleration control of the flier arms during the armature winding process need not be the same magnitude. In many cases it is desired to have a fairly large acceleration time to reduce the negative effects on the wire, as described above. These negative effects are minimal during the deceleration phase of the wind, since the forces added by velocity, acceleration, and impulse are typically negative rather than positive in magnitude. Conventional control system applications do not permit the deceleration phase to be independent from the acceleration phase, thus adding to the wind time. Implementing one of the hardware profiles shown in FIGS. 1, 2 and 3, which allow either independent programming of the acceleration and deceleration values or program control of the motor profile to the extent to which the desired profile may be created. Example 2 uses the Delta-Tau Programmable Multi-Axis Controller (PMAC) "PVT" instruction ("Set Position-Velocity-Time mode" instruction) , incorporating a parameterized winding program which separates acceleration and deceleration times. In this example, the parameters entered include 75 turns with a peak velocity of 3500 RPM, using an acceleration and deceleration time of 750 milliseconds, with 375 milliseconds at both the beginning and end of the total acceleration time. As shown by the winding profile of FIG. 6, this represents a winding velocity profile in which the acceleration ramp, designated 12, is independent of the deceleration ramp, designated 14, and both ramps are completely smooth. In addition to the aforementioned benefits of "S"-curve acceleration and deceleration, a reduction in wind time from 1.98 to 1.86 seconds is also realized, as indicated in FIG. 6 because or the reduction in the deceleration ramp time. Following are the instructions to the PMAC used to obtain the independent acceleration and deceleration ramps with "S"-curves of FIG. 6. * Program (Parameterized) CLOSE DELETE GATHER OPEN PROG 1 CLEAR ABS IF (P100 1) PVT(P104-P101) X(P105) : (P106) ENDIF IF (P100 2) PVT(P107-P104) X(P108) : (P109) ENDIF IF (P100 3) PVT(P110-P107) X(P111) : (P112) ENDIF IF (P100 4) PVT(P113-P110) X(P114) : (P115) ENDIF IF (P100 5) PVT(P116-P113) X(P117) : (P118) ENDIF IF (P100 6) PVT(P119-P116) X(P120) : (P121) ENDIF IF (P100 7) PVT(P122-P119) X(P123) : (P124) ENDIF IF (P100 8) PVT(P125-P122) X(P126) : (P127) ENDIF IF (P100 9) PVT(P128-P125) X(P129) : (P130) ENDIF IF (P100 10) PVT(P131-P128) X(P132) : (P133) ENDIF IF (P100 11) PVT(P134-P131) X(P135) : (P136) ENDIF IF (P100 12) PVT(P137-P134) X(P138) : (P139) ENDIF IF (P100 13) PVT(P140-P137) X(P141) : (P142) ENDIF IF (P100 14) PVT(P143-P140) X(P144) : (P145) ENDIF DWELLO P1=0 CLOSE * Parameters (Calculated) FLIER PVT Absolute Wind Input Parameters ... AccelTime = 750.0 MSec AccelSPercent = 100 % SlowVelocity = 3500.000 RPM FastVelocity = 3500.000 RPM MaxVelocity = 3500.000 RPM (Reference) DecelTime = 500.0 MSec DecelSPercent = 100 % Start Position = -1.000 Turns End Position = +74.947 Turns Distance = +75.947 Turns DistanceUntilFast = +1.650 Turns Calculated Parameters... Segments (P100) = 6 Time(mSec), Position (Turns) , Velocity (Turns/sec) P101= 0.0 P102= -1.000 P103= 0.000 P104= 345.4 P105= +2.358 P106= 29.167 P107= 690.8 P108= +19.148 P109= 58.333 P110= 1417.1 Plll= +61.515 P112= 58.333 P113= 1647.3 P114= +72.708 P115= 29.167 P116= 1877.6 P117= +74.947 P118= 0.000 Example 3 - Synchronous Parallel Sequencing Integrating the velocity profile results in the distance traveled by the fliers or the workpiece at any given point during the cycles of operation of their respective drive motors. This is essentially the area under the velocity curve. Viewing FIG. 7, which shows an arrow 20 pointing to near the end of a flier winding sequence, reveals that much time is spent at the end of the sequence when there is very little additional flier travel. Synchronous parallel sequencing eliminates this time loss by advancing the next operation in the machine sequence (at the arrow) before the total motion is complete. During the wind, at or near the position where the fliers pass the commutator on the last turn, the shield is fired retracted since it is the next sequential operation. The Delta-Tau Programmable Multi-Axis Controller (PMAC) "P" instruction ("Report motor position" instruction) is continuously executed during the wind to read the flier motor position. When the desired trigger position is read, the corresponding commutator shield outputs are fired in order to start the shield retracting. When the flier motion is completed, the commutator shield is already on its way retracted, exposing a commutator tang as required to hook the next coil lead - the next step in the winding process. Those skilled in the art will recognize that signal based motion controllers other than the Delta Tau Data Systems PMAC controllers may be used in the practice of this invention. Also it will be recognized that the synchronous parallel sequencing method can be used for controlling essentially every type of manufacturing machine that undergoes different sequential operating steps. Thus the operation of lathes and a wide variety of other manufacturing machines can be improved by the application of synchronous parallel sequencing. Although the "S"-curve acceleration and deceleration ramps are preferred, it will be recognized that other ramp configurations could be used when controlling a motor to obtain independent acceleration and deceleration or synchronous parallel sequencing in accordance with this invention. While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various alterations in form and detail may be made therein without departing from the spirit and scope of the invention.

Claims: The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A control system for an armature winding machine comprising a programmable digital signal processor based servo motion controller, a servo motor with feedback, and an industrial computer. 2. A control system for an armature winding machine comprising a programmable digital signal processor based servo motion controller and a servo motor with feedback, said motion controller controlling both motion control and the sequential functionality of the machine. 3. A machine control system for an armature winding machine comprising a servo motor controller, a servo motor with feedback, and a programmable logic controller based control, said servo motor controller being used in a command/response mode, hosted by said programmable logic controller, wherein the programmable logic controller issues motion commands while controlling the sequential functionality of the machine. 4. A method of controlling the operation of an armature winding machine having a rotating flier to wind coils driven by a servo motor, comprising the steps of controlling the operation of the drive motor to produce ^"-curve acceleration and deceleration ramps. 5. The method of claim 4 wherein said acceleration ramp is generated independently of said deceleration ramp. 6. A method of controlling the operation of an armature winding machine having a rotating flier to wind coils driven by a servo motor, comprising the steps of controlling the operation of the drive motor to produce acceleration and deceleration ramps wherein said acceleration ramp is generated independently of said deceleration ramp. 7. The method of claim 6 wherein said acceleration ramp extends over a longer period of time than said deceleration ramp. 8. A method of controlling the operation of a manufacturing machine that has sequential operating steps comprising initiating the operation of a first step, and before completion of said first step, initiating the operation of a second step using a digital signal based motion controller.

Inventors: BRUNSWICK JAY J, COOK CHAD D, HEATON MARK T, MONNIN BRADLEY T, BRUNSWICK, JAY, J., COOK, CHAD, D., HEATON, MARK, T., MONNIN, BRADLEY, T.
Applicants: GLOBE PRODUCTS INC, GLOBE PRODUCTS INC.
Application year: 1998
Main classification: H02K15
IPC codes: G05B19, H02K15