Abstract:
The apparatus and method of the invention vary the sensitivity slope of the FNR control lever of an agricultural windrower, such that speed commands outputted through a first range of movements of the FNR lever are slower and increase less rapidly than commands outputted through a second range of movements greater than the first range, the first range corresponding to movements in closer proximity to the neutral position of the FNR lever. The different show is achieved by using different slopes for transfer function signals for the first and the second ranges of positions of the FNR lever.

Description:
This application claims the benefit of U.S. Provisional Application No. 60/699,640, filed Jul. 15, 2005. 
    
    
     TECHNICAL FIELD 
     The present invention relates to agricultural windrowers and, more particularly, to apparatus and a method, embodied in a computer program, to vary the sensitivity slope of the FNR control lever of an agricultural windrower. 
     BACKGROUND OF THE INVENTION 
     U.S. Provisional Application No. 60/699,640, filed Jul. 15, 2005, is incorporated herein in its 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. 
     Typically, windrowers utilize differential steering, wherein the drive wheels of the windrower are driven at different speeds, to effect changes in direction. Also typically, windrowers are driven along long swaths through a field to be harvested, then are turned by a large angle, for instance 180°, into the next swath to be harvested. Windrowers utilize a sidewardly elongate header for severing crops from the field and redepositing the severed crops on the field in a windrow. The width of the header increases complexity of steering movements required for maneuvering the windrower. And, from time to time, the header is removed from the windrower and replaced, either with the same header, or a different header. For replacement, elongate, forwardly extending arms of the windrower are typically maneuvered into position beneath the header for engaging cups thereon when the arms are raised, for installing the header on the windrower. Such maneuvers can require slow speed precise movements of the windrower. Windrowers often include a selectable low speed range which is utilized for such slower speed movements. However, even when in the slow speed range, it has been found that it would be desirable to have a capability for movements of the FNR lever to command even slower movements, to enable better control during steering and header installation. 
     It is therefore desirable to have a capability to more precisely effect slow speed movements and maneuvers of a windrower, utilizing a FNR lever, for turning, installing a header, and the like. 
     SUMMARY OF THE DISCLOSURE 
     Accordingly, what is disclosed is an apparatus and method for effecting slow speed movements and maneuvers of a windrower utilizing a FNR lever, for turning, installing a header, and like maneuvers. 
     According to a preferred aspect of the invention, the apparatus includes a FNR lever assembly including a FNR lever having a neutral position and movable from the neutral position in a first direction through a range of positions to a position fully moved in the first direction, and the FNR lever being movable from the neutral position in a second direction through a range of positions to a position fully moved in the second direction. The apparatus includes at least one sensor 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, which sensor is preferably a potentiometer. The apparatus additionally includes a programmable control module in connection with the at least one sensor and with apparatus for controlling a speed of the propulsion driveline, the control module being programmed and operable for receiving the signals outputted by the at least one sensor and generating transfer function signals for determining speed command signals to be outputted to the apparatus for controlling the speed of the propulsion driveline as a function of the received signals. The transfer function signals for a first range of positions of the FNR lever, preferably for producing slower speeds of the propulsion driveline, have a first slope. The transfer function signals for a second range of positions of the FNR lever, preferably for producing higher speeds of the propulsion driveline, and greater than the first range of positions, have a second slope, the first slope being less than the second slope. 
     The first range of positions of the FNR lever preferably correspond to positions between the neutral position and a predetermined position between the neutral position and the fully moved position, and the second range of positions of the lever correspond to positions between the predetermined position and the fully moved position. The different slopes can be applied to both directions of movement, or just one. 
     As a result, speed commands inputted through movements of the FNR lever within the first range will have less magnitude, and change less rapidly, than speed commands included through movements of the lever within the second range. Thus, more precise control of speed within the slower speed ranges is achieved, to facilitate maneuvers for turning and installation of a header or the like. 
     According to another preferred aspect of the invention, the first slope is about 50 percent less than the second slope, although other slope differences can be used as desired or required for a particular application. 
     According to another preferred aspect of the invention, the transition point is calculated automatically from Neutral and Full Forward positions derived during FNR calibration, thus independent of FNR sensor and mechanical components tolerances. 
    
    
     
       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 partial 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 simplified graphical representation of velocity verses FNR lever position obtained according to a preferred embodiment of a method of the instant invention; and 
         FIG. 4  is a listing of lines of code of a computer program embodying steps of a preferred embodiment of a method of the instant invention. 
     
    
    
     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  FIG. 2 , 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, preferably including one or two 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 potentiometers  42  to output varying signals representative of the position of lever  40 , which signals comprise 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, 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 outputs of one or both potentiometers  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, and the voltage output of one or both of the potentiometers  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 , as is a field cruise switch  58 . 
     Tractor control module  46  is connected to a second tractor control module  60  via a controller area network (CAN). Tractor control module  60  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  60 , based on the voltage outputs of at least one 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 arms  32  and  34  to module  60  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 is communicated via conductive paths  48  to module  60 . Differences in the speed readings is also indicative of steering movements. 
     More particularly with regard to the advantages of the present invention, FNR lever  40  is movable from the neutral position in a first direction through a range of positions to a position fully moved in the first direction, and from the neutral position in a second direction through a range of positions to a position a fully moved in the second direction. One direction of movement will effect movement of windrower  10  in the forward direction, and the other direction will effect movement in the rearward direction. The control module is programmed and operable for receiving the signals outputted by the potentiometer or potentiometers  42 , and generating transfer function signals for determining speed command signals to be outputted to the solenoids controlling the propulsion cylinder  64  for controlling the speed of propulsion driveline  22  as a function of the received signals. 
     Referring also to  FIG. 3 , the transfer function signals for speed commands for forward movements of windrower  10  are denoted by a trace  68 , and the transfer function signals for speed commands for rearward movements are denoted by a trace  70 . A first range of positions of FNR lever  40  in the forward direction extends between line N and about point A, representing slower forward speeds of windrower  10 , and a second range of positions in the forward direction extends between about point A and full forward, which is the full extent of movement of FNR lever  40  in the forward direction. The points A and B are automatically derived during a calibration procedure performed by the operator. Similarly, a first range of positions of FNR lever  40  in the rearward direction extends between line N and about point B, and a second range of positions in the rearward direction extends between point B and full reverse, which is the full extent of movement of lever  40  in the rearward direction. The first range of forward positions between line N and point A has a first slope, and the second range of forward positions between point A and full forward, has a second slope, the first slope preferably being about 50% of the second slope. Similarly, the first range of rearward positions between line N and point B has a first slope, and the second range of rearward positions between point B and full rearward, has a second slope, again, the first slope preferably being about 50% of the second slope. 
     As a result, speed commands inputted through movements of FNR lever  40  within the first range in both directions will have less magnitude, and change less rapidly, than speed commands included through movements of lever  40  within the second range. Thus, more precise control of speed within the slower speed ranges is achieved, to facilitate maneuvers for turning and installation of a header or the like. 
     The preferred method of the invention is embodied in a computer program, lines of which are set forth in  FIG. 4 . 
     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.