Abstract:
Apparatus and a method providing neutral safeing for a propulsion system of an agricultural windrower having a FNR lever assembly including a FNR lever movable in relation to a neutral position in first and second directions, and a sensor for sensing positions of the FNR lever as the lever is moved and outputting signals representative thereof, the sensor being configured such that the signals outputted thereby are to have signal values within a predetermined range of values and/or which will change within a predetermined rate of change, a programmable control module in operative control of a park brake and programmed and operable for monitoring the signals and comparing the values of the signals to the predetermined range, and if the value of any of the signals is outside of the predetermined range, then automatically engaging the park brake.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/699,641, filed Jul. 15, 2005, and U.S. Provisional Application No. 60/699,943, filed Jul. 16, 2005. 
    
    
     TECHNICAL FIELD 
     The present invention relates to vehicular safeing and, more particularly, to apparatus and a method providing neutral safeing for a propulsion system of an agricultural windrower. 
     BACKGROUND OF THE INVENTION 
     U.S. Provisional Application No. 60/699,641, filed Jul. 15, 2005, and U.S. Provisional Application No. 60/699,943, are incorporated herein in their entirety by reference. U.S. Pat. No. 6,901,729 is also incorporated herein in its entirety by reference. 
     Vehicles, such as, but not limited to, agricultural windrowers, can utilize control algorithms for translating input signals, for instance, from operator controlled input devices such as a forward-neutral-reverse (FNR) lever, also sometimes referred to as a multi-function-handle (MFH), to systems to be controlled thereby, such as the propulsion driveline. 
     It is therefore desirable to have a capability to monitor the performance of such control algorithms, to ensure that the input commands are being accurately and safely translated into machine operations and movements. This can be generally referred to as propulsion system safeing. It is also desirable to have the capability to determine or sense when a controlled system, such as a propulsion driveline, is no longer tracking a reference input signal sufficiently well. A degradation in the tracking capability can occur for any of several reasons, such as an interrupted or corrupted communication path, such as due to electrical noise and/or damage to a conductive path such as a wiring harness, physical wear or damage, and the like. It is also desirable to have the ability to determine or sense when the controlled system is overshooting or undershooting a system bounds. For instance, a propulsion system may drive a vehicle such as a windrower at a speed greater than a set speed. A system can overshoot (measured system output exceeds the desired output value) or undershoot (measured system output is less than the desired output value), which may indicate that a controller for the output has become unstable. Safeing in the instance of these conditions, will provide a manner of returning to a safe mode, which can include automatically going to a neutral mode, and/or shutting down the propulsion system. 
     It is also to have the capability for providing neutral safeing, that is, the ability to ensure that when the FNR lever is moved to the neutral position, or is already in the neutral position, the windrower is prevented from moving either in the forward, or the reverse direction. 
     SUMMARY OF THE DISCLOSURE 
     Accordingly, what is disclosed is apparatus and a method for providing neutral safeing of a propulsion system of an agricultural windrower. 
     According to the invention, a FNR lever assembly includes a FNR lever having a neutral position and is movable in relation to the neutral position in a first direction and in a second direction opposite the first direction. At least one sensor is disposed and operable for sensing positions of the FNR lever as the lever is moved in the first and second directions and outputting signals representative thereof, and is configured such that the signals outputted thereby are to have signal values within a predetermined range of values. A combination of a hard-wired logic circuit and a programmable control module are connected with at least one sensor for receiving the signals therefrom, and are connected in operative control to control electrical power to the propulsion driveline 
     According to another aspect of the invention, the propulsion driveline returns to a zero-machine state when electrical power is removed from the propulsion driveline. 
     According to another aspect of the invention, the electrical power to the propulsion driveline is removed if the park brake is engaged. 
     According to another aspect of the invention, the control module output is interlocked with the hard-wire logic circuit and the interlock must be enabled to provide electrical power to the propulsion driveline. 
     According to still another aspect of the invention, a latch circuit is provided and energizable for providing power to the propulsion driveline, the control module being connected in operative control of the latch circuit, and the control module being operable for engaging the electrical power to the propulsion driveline. 
     As another advantage, the FNR lever must be moved out of the neutral position to latch a latching circuit for sending power to the propulsion controls. 
     According to still another aspect of the invention, the control module is programmed such that when the FNR lever transitions from Neutral-to-Forward or from Neutral-to-Reverse, electrical power is sourced from the control module from the associated neutral safeing hard-wire logic circuit. 
     In another aspect of the invention, the control module is programmed such that when the FNR lever transitions from Forward-to-Neutral or from Reverse-to-Neutral, electrical power is removed via the control module from the associated neutral safeing hard-wire logic circuit after a predetermined delay time. 
     According to still another aspect of the invention, electrical power is immediately removed via the control module in response to specific critical faults associated with loss of module control of the propulsion driveline. 
     According to still another aspect of the invention, electrical power is removed via the control module in response to specific critical faults associated with loss of operator control of the propulsion driveline, following control module return of the propulsion driveline to the neutral state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a side elevational view of a windrower of the type with which the invention may be used, including a header for severing crops from a field, mounted on a front end of the windrower; 
         FIG. 2  is a simplified diagrammatic representation of a propulsion driveline of the windrower incorporating aspects of the instant invention; 
         FIG. 3  is a schematic of circuitry of the propulsion driveline; 
         FIG. 4  is a schematic of other aspects of circuitry of the propulsion driveline; 
         FIG. 5  is another schematic of circuitry of the propulsion driveline; 
         FIG. 6  is another schematic of circuitry of the propulsion driveline; 
         FIG. 7  is a listing of code of a computer program incorporating steps of a preferred embodiment of the method of the invention; 
         FIG. 8  is a continuation of the listing; 
         FIG. 9  is a continuation of the listing; 
         FIG. 10  is a continuation of the listing; 
         FIG. 11  is a continuation of the listing; 
         FIG. 12  is a continuation of the listing; 
         FIG. 13  is a continuation of the listing; 
         FIG. 14  is a continuation of the listing; 
         FIG. 15  is a continuation of the listing; 
         FIG. 16  is a continuation of the listing; 
         FIG. 17  is a continuation of the listing; 
         FIG. 18  is a continuation of the listing; 
         FIG. 19  is a continuation of the listing; and 
         FIG. 20  is a continuation of the listing; 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Many of the fastening, connection, processes and other means and components utilized in this invention are widely known and used in the field of the invention described, and their exact nature or type is not necessary for an understanding and use of the invention by a person skilled in the art, and they will not therefore be discussed in significant detail. Also, any reference herein to the terms “left” or “right” are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel. Furthermore, the various components shown or described herein for any specific application of this invention can be varied or altered as anticipated by this invention and the practice of a specific application of any element may already by widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. Still further, in this description, the terms FNR lever, multi-function handle and MFH referred to the same item, and therefore are interchangeable. 
       FIG. 1  shows a self-propelled windrower  10  incorporating the apparatus and method of the invention; however, it will be appreciated that the principles of the present invention are not limited to a self-propelled windrower, or to any specific type of harvesting machine. 
     In the illustrated embodiment, the self-propelled windrower  10  comprises a tractor  12  and a header  14 , the header  14  being attached to the front end of the frame  16  or chassis of the tractor  12 . The header may be of generally any suitable construction and design, and may include not only crop-harvesting mechanisms, but also crop conditioners such as elongate rolls  15 . Such attachment of the header  14  to the frame  16  is achieved through a pair of lower arms  18  (only the left one being shown, the right being generally the same) pivoted at one end to the frame  16  and at the other end to the header  14 , as well as through a central upper link  20 . 
     One or more cylinders, such as individual lift and flotation cylinders, or a single lift/flotation cylinder, interconnects the lower arm  18  and the frame  16  on each side of the header. 
     Typical features and operation of a system for controlling the lift and flotation functions for a header, such as header  14  depicted herein, are disclosed in U.S. Pat. No. 6,901,729, incorporated herein by reference. 
     Referring also to  FIGS. 2 ,  3 ,  4  and  5 , windrower  10  includes a propulsion driveline  22  controllably operable using operator controls for rotatably driving a left wheel  24  and a right wheel  26  for propelling windrower  10  over a ground or other surface. Hydraulic motors (not shown) in connection with each wheel  24  and  26 , respectively, are provided with fluid under pressure by hydraulic pumps  28 , for driving the wheels. The pumps  28  can be differentially controlled for supplying different and varying amounts of pressurized fluid to the hydraulic motors, for effecting desired movements of windrower  10 , including steering movements, as effected by operation of a rotatable and longitudinally movable propulsion rod  30  in connection with pintel arms  32  and  34  movable for controlling displacement of pumps  28  in the well-known manner. Steering commands are inputted to driveline  22  by an operator via an operator control which is a steering wheel  36  disposed in an operator cab  38  of windrower  10 . Steering movements of windrower  10  are effected by rotating respective wheels  24  and  26  at different speeds. Propulsion speed and direction commands are inputted to driveline  22  by an operator via an operator control which is a FNR lever  40  also disposed in cab  38 . 
     FNR lever  40  is configured to operate a suitable sensor or sensors operable for generating varying information or outputs representative of the position of lever  40  when lever  40  is manipulated or moved, including a rotary potentiometers  42  and a neutral switch  44 , each of which is connected to a tractor control module  46  via a suitable conductive path or paths  48 , which can be, for instance, a wire or wires of a wiring harness, an optical path, a wireless path, or the like. Movements of FNR lever  40  in relation to the neutral position will cause potentiometer  42  to output a varying signal representative of the position of lever  40 , the signal comprising voltages. It is desired for these voltage signals to very precisely indicate the position of lever  40 , such that precise control of the forward and rearward movements of windrower  10  can be achieved. 
     Neutral switch  44  is also mounted and configured such that movements of FNR lever  40  into the neutral position, and out of the neutral position, will cause changes in the operating state of switch  44 . Here, forward and rearward movements of FNR lever  40  from a generally straight up neutral position shown, with a park brake switch in a state to disengage the park brake, will effect a change of state of switch  44  which will be outputted to control module  46 , which will responsively power up the propulsion driveline, control module  46  controlling the propulsion speed of windrower  10  as a function of the voltage output potentiometer  42 . Similarly, rearward movement of FNR lever  40  from the neutral position will effect a change of state of switch  44  outputted to control module  46  to affect operation of the propulsion driveline in the reverse direction if the park brake is in a disengaged state, and the voltage output of potentiometer  42  will be used to control reverse speed. It is also desired that, when lever  40  is moved into the neutral position, the propulsion system be controlled to positively de-stroke or otherwise transition into a non-propelling state over time, such that abrupt stoppage does not occur. 
     Other operator controls include a park brake switch  50  also connected to tractor control module  46  via a conductive path  48 , and via another conductive path  48  to a key switch  52  and a start relay  54  in connection with a starter of engine  22  and with tractor control module  46 . A 2-speed switch  56  is connected to tractor control module  46  via another conductive path  48 . 
     Tractor control module  46  is in connection with a rotary potentiometer  62  via a conductive path  48 , potentiometer  62  being operable for outputting information representative of the position of a propulsion cylinder  64 . Propulsion cylinder  64  is extendable and retractable by solenoids controlled by tractor control module  46 , based on the voltage output of potentiometers  42 , to move propulsion rod  30  longitudinally for changing the stroke of the hydraulic pumps  28  via the angle of the pintel arms  32  and  34 , for effecting propulsion of the windrower. A rotary potentiometer  66  is operable for outputting information representative of the position of pintel arm  34  to module  46  via another conductive path  48 , providing information representative of differential stroking of pumps  28  to effect steering movements. Information representative of speed of respective wheels  24  and  26  is determined by reluctance speed sensors and communicated via conductive paths  48  to module  46 . Differences in the speed readings is also indicative of steering movements. 
     Other illustrated elements of propulsion driveline  22  include a park brake latch relay  70 ; a propulsion enable relay  72 ; a propulsion interlock relay  74 ; a brake valve solenoid  76 ; a ground speed high solenoid  78 ; propulsion cylinder position sensor  82  incorporating dual rotary potentiometer  62  ( FIG. 2 ); a pintel arm position sensor  84  incorporating rotary potentiometer  66  (also  FIG. 2 ); left and right ground speed sensors  86  and  88 ; a propulsion forward solenoid  90 ; and a propulsion reverse solenoid  92 . 
     As noted above, the instant invention utilizes control module  46  to monitor the propulsion commands inputted thereto by potentiometer  42  indicative of the position of FNR lever  40 . Essentially, the output of potentiometer  42  is required for signaling propulsion commands or inputs. The output of dual potentiometer  62  is indicative of the position of propulsion cylinder  64  of the propulsion driveline  22 , but two are used (dual Hall tracking) and the voltage outputs are continually summed. If the sum does not equal a predetermined value, here 5 V, it is determined that an error in the voltage signal of one or both of the potentiometers is present. The position of propulsion cylinder  64  (and thus the output of potentiometers  62 ) should, if normally operating, correspond to or track the inputted command from potentiometer  42 , with consideration of normal deviations such as due to hysteresis, time lag in executing the propulsion commands, and the like dv/dt (changing voltage over time) thresholding of the FNR potentiometer is used to identify/evaluate any faults. 
     Reference input commands r (e.g., voltage inputted through the position of FNR lever  40  by potentiometer  42 ) are matched with responsive system/hardware outputs y (e.g., voltages outputted by potentiometers  62 ) to derive tracking errors e by control module  46  (Controller H). Tracking errors e are processed to determine any faults (Fault Detection F). This is preferably done using the following exponentially decaying integrator, also used for integration of current errors:
 
propulsion cylinder integrator=∫ e   a(T-t) *(position error) dT , with limits of integration 0 to t.
 
electrical current integrator=∫ e   a(T-t) *(current error) dT , with limits of integration 0 to t.
 
The integrals are approximated (using integer math) via the following formula in discrete time: integral(k)=error(k)+[A*integral(k−1)] where, k is the sample time, and 0&lt;A&lt;1=decay rate.
 
to give the algorithm a forgetting type property wherein the most recent error signals are weighted more heavily than ones further in the past. A predetermined threshold is set on this exponentially decaying integrator to indicate when the controlled system is no longer tracking sufficiently well. When the value of the exponentially decaying integrator exceeds the threshold, appropriate action is taken to preserve the integrity and safety of the system, which can include outputting of a fault signal to the operator, an automatic system shutdown, or the like.
 
     Another algorithm for monitoring the controller stability checks bounds. When the system is overshooting (measured system output exceeds the desired output value) or undershooting (measured system output is less than the desired output value) it is checked to make sure that the measured output value isn&#39;t at a corresponding saturation limit of the hardware, which would be an indication that the controller has become unstable. 
     If there is a fault, solenoids A and B ( FIG. 2 ) controlling the valve which directs hydraulic fluid to the chambers of propulsion cylinder  64  are de-energized, to allow the spring associated with propulsion cylinder  64  to take propulsion rod  30  to neutral, and the park brake is allowed to be applied. 
     Referring also to  FIGS. 7-20 , lines of code of an actual computer program embodying the steps of the method of the invention for providing neutral safeing is disclosed. The notes accompanying the lines of code describe many features of the method of the invention. In the code, the FNR lever is identified as the MFH. 
     As one mode of neutral safeing, if the signal values outputted by potentiometer  42  or potentiometers  62 , are outside of a predetermined range, control module  46  is automatically operable for engaging the park brake. This can involve, for instance de-energizing park brake latch relay  70 . 
     As another neutral safeing function, control module  46  can be programmed such that when the park brake is engaged and an engine of the windrower is operating, the control module allows the operator to manually disengage the park brake (de-energizes or unlatches relay  70 ) when FNR lever  40  is in the neutral position and steering wheel  36  is set within a predetermined range from a straight ahead position, which range can be, for instance, but is not limited to, 80° in either direction from a straight ahead position. 
     As another neutral safeing function, control module  46  can be programmed to engage the park brake if start switch  52  is switched to its off position. 
     As still another safeing function, control module  46  can be programmed to engage the park brake if FNR lever  40  is in the neutral position and a seat switch indicates that an operator has not been seated on an operator seat of the windrower for a predetermined time. 
     In another safeing mode, control module  46 / 60  is programmed to automatically engage the park brake if potentiometer  42  is outputting signals representative of FNR lever  40  being in a position other than the neutral position and neutral switch  44  is in an operating state representative of FNR lever  40  being in the neutral position; and if the potentiometer signals are representative of FNR lever  40  being in the neutral position and neutral switch  44  is in an operating state representative of FNR lever  40  being in other than the neutral position. 
     Also, if a comparison of the signals outputted by potentiometers  42  and  62  indicate that propulsion cylinder  64  is stuck, control module  46 / 60  can automatically engage the park brake. 
     Controller  46 / 60  can also be programmed to only allow operation of key switch  52  for initiating operation of propulsion driveline  22  when park brake switch  50  is in a state for disengaging the park brake. 
     Still further, as another neutral safety mode, control module  46 / 60  can be programmed such that when the comparison of the rate of change of the FNR lever position and the rate of change of the propulsion cylinder position are different, the park brake can automatically be engaged. 
     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the inventions. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.