Abstract:
A method for automatically controlling the extension and steering of left side and right side wheels ( 112, 114 ) in a work vehicle ( 102 ), the vehicle ( 102 ) having a digital microcontroller ( 172 ) configured to control the steering of left side and right side wheels ( 112, 114 ) by electronically scanning data from identifiers ( 136, 138, 140, 141 ) on the left and right side wheels ( 112, 114 ) that are indicative of wheel geometry of the left and right side wheels ( 112, 114 ); electronically transmitting the data to the digital microcontroller ( 172 ); calculating steering angle limits in the digital microcontroller ( 172 ) based upon the data; and electronically facilitating in the digital microcontroller ( 172 ) that the left and right side wheels ( 112, 114 ) are steered within the steering angle limits during subsequent operations of the work vehicle ( 102 ).

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to agricultural harvester vehicles. More particularly it relates to suspensions for agricultural harvester vehicles. Even more particularly it relates to methods for automatically controlling steering for agricultural harvester vehicles. 
       BACKGROUND OF THE INVENTION 
       [0002]    Agricultural harvester vehicles have been proposed that shall include axles that are automatically adjustable during operation of the agricultural harvester vehicle in the agricultural field. 
         [0003]    In one arrangement, an electronic controller in the vehicle will automatically extend and retract the axles, wheels and tires fixed thereon; as well as automatically steer the axles under computer control as the vehicle travels through the field. 
         [0004]    In one specific arrangement, the agricultural harvester will extend the axles, and thus move the wheels away from the sides of the vehicle at the same time it steers the wheels to one side or another from the straight-ahead position. The wheels can thereby be held as close as possible to the sides of the vehicle when the vehicle was traveling in the straight-ahead course, and can be extended from the sides of the vehicle to provide clearance as the wheels are steered to the left and to the right, while keeping the wheels as close as possible to the sides, of the vehicle. 
         [0005]    One problem with this arrangement is that a wide variety of wheels and tires with widely varying dimensions may be mounted on the ends of the axles. This means that no single setting of axle extension versus steering angle can be provided that will prevent the interference of all possible wheels and tires that may be attached to the vehicle. 
         [0006]    Whenever the operator changes his wheels and tires to other wheels and tires having different dimensions he must therefore adjust steering limits of each tire and wheel combination to ensure that the tire does not rub against the side of the combine when the wheels are turned to the left, turned to the right, or when the axles are fully retracted into the sides of the vehicle. This iterative process is unreliable, however. If the operator miscalculates when providing this information to the electronic controller it steers the vehicle and extends the axles severe damage may result when the wheels interfere with the sides of the vehicle. 
         [0007]    One way to reduce this possibility for error is to automate the process of programming the controller by providing wheel and tire information to the controller electronically. 
         [0008]    U.S. Pat. No. 7,504,947 B2 describes the process of storing tire information in an RFID tag that is permanently embedded in the tire and electronically scanning that tag to store the information. This advantageously permits an unskilled operator to make a perfect copy of any data stored in the tire, thereby reducing errors in data collection. 
         [0009]    U.S. Pat. No. 7,348,878 discloses an electronic system for continuously monitoring these RFID tags (and pressure sensors mounted on vehicle wheels) to continuously monitor the condition of the tire (i.e. tire pressure) and to signal the operator when the pressure is out of range. 
         [0010]    In this arrangement, radio receivers permanently connected to the vehicles electronic controller area network are disposed adjacent to the RFID tags and continuously receive information radioed from the tags. This information is provided to an electronic controller on the controller area network (CAN) which processes the information and determines whether or not the tires are properly inflated. If not, the controller drives a display to signal the operator. 
         [0011]    Neither of these teach that the wheel information should be used to control the steering system of the vehicle. 
         [0012]    What is needed, therefore, is a method and apparatus for more reliably determining and controlling the range of steering and axle extension (more generally the movement and positioning) of the wheels during the agricultural harvester&#39;s normal operation. 
         [0013]    It is an object to provide such a method and apparatus in one or more of the embodiments described below and claimed in the appended claims. 
       SUMMARY OF THE INVENTION 
       [0014]    In accordance with a first aspect of the invention, an agricultural harvester vehicle is provided having a chassis upon which two front drive wheels and two rear steerable wheels are mounted. The rear steerable wheels are mounted on axles that can be steered or extended (or both) under computer control. A digital microcontroller is provided to steer or extend the rear wheels (or both). 
         [0015]    The digital microcontroller is configured to electronically receive tire or rim information (or both) that is scanned from the tire, rim, or both and based upon this information, to establish steering limits and axle extension or retraction limits beyond which the digital controller will not permit the wheels to be steered, extended, or retracted. 
         [0016]    The operator scans identifiers on the wheel which may be visual indicia or electronic data stored in embedded RFID tags to gather the wheel information. The operator communicates this scanned information to the microcontroller, which then uses the data to determine the appropriate axle extension limits and wheel steering limits. 
         [0017]    The data scanned from identifiers on the wheel (tire, rim or both) may be geometric information, in which case the digital microcontroller can use it directly to geometrically calculate acceptable steering angle and axle retraction limits. Alternatively, it may be manufacturers&#39; model numbers, SKU&#39;s or other non-geometric information. In this alternative case, the digital microcontroller has an internal lookup table that associates model information with geometric information from which it can derive wheel geometry and thus the appropriate steering angle and axle retraction limits. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1  is a plan view of an agricultural harvesting vehicle in accordance with the present invention. 
           [0019]      FIG. 2  is a fractional detail view of the right rear wheel of  FIG. 1  showing the location of wheel and tire identifiers. 
           [0020]      FIG. 3  is a fractional detail view of the wheel of  FIGS. 1-2  mounted on the right rear axle. 
           [0021]      FIG. 4  is a schematic view of the control system for steering the agricultural harvester. 
           [0022]      FIGS. 5A-5B  illustrate how the steering angle limits are varied by the control system based upon tire information and wheel information received from the identifiers located on the wheel and/or tire. 
           [0023]      FIGS. 6A-6B  illustrate how the axle retraction limits are varied by the control system based upon tire information and wheel information received from the identifiers located on the wheel and/or tire. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    In  FIG. 1 , an agricultural harvester  100  is shown in plan view. It includes an agricultural harvester vehicle  102  to which a harvesting head  104  is attached. The harvesting head  104  is supported on a feederhouse  106  which extends forward from the front of the agricultural harvester vehicle  102 . 
         [0025]    Agricultural harvester vehicle  102  is supported on four wheels including a left front drive wheel  108 , a right front drive wheel  110 , a left rear steerable wheel  112 , and a right rear steerable wheel  114 . 
         [0026]    Front drive wheels  108  and  110  do not steer. Instead, they are coupled to hydraulic motors with reduction gear boxes (not shown) that in turn are fixed directly to the chassis  116  of agricultural harvester vehicle  102 . 
         [0027]    Rear steerable wheels  112 ,  114  are supported on extendable axles, and can be steered to the left and to the right away from their central straight-ahead position shown in  FIG. 1 . 
         [0028]    A grain tank  118  is located at the top of the agricultural harvester vehicle  102  to store grain gathered by harvesting head  104 . An elongate unloading conveyor  120  extends from chassis  116  to convey grain from grain tank  118  to a grain truck or cart (not shown) that is disposed adjacent to the agricultural harvester  100  during unloading. 
         [0029]    In  FIG. 2 , the right rear steerable wheel  114  is shown. The right side steerable wheel  114  includes a rim  122  on which a tire  124  is mounted. Wheel  114  includes a mounting surface  126  that is generally perpendicular to and symmetric about the central rotational axis  128  of wheel  114 . Mounting surface  126  is flat, conical, or dished and is offset slightly to one side of a plane of symmetry  130 . The plane of symmetry  130  bisects wheel  114  and is spaced an equal distance “d” from the innermost left side  132  and the outermost right side  134  of wheel  114 . 
         [0030]    Identifiers  136  and  138 ,  140  and  141 , such as electronically scannable tags (e.g. RFID tags) or visual indicia, may be fixed on or embedded in the tire  124  and the rim  122 , preferably on (or in) both side walls or side facing surfaces of the tire  124  and rim  122 , respectively. 
         [0031]    Identifiers  136 ,  138 ,  140 ,  141  are configured to store data regarding the tire and rim and to transmit that information by radio waves (if the identifiers are RFID tags, for example) or by light reflected off the surface (if the identifiers are visual indicia such as barcodes, characters, or the like) to a scanning device. 
         [0032]    Scanning devices (not shown) may include a laser scanner, a barcode scanner, a two-dimensional barcode scanner, or an electronic camera configured to read the visual indicia. Scanning devices may also include radio receivers configured to read RFID tags or similar devices. 
         [0033]    Identifiers  136 ,  138  are located on or embedded within tire  124  and preferably include information identifying characteristics of the tire, including the tire manufacturer, SKU number, model number, manufacturing date, tire dimensions, load limits, speed rating, and other identifiers indicating the identifiers, types, or dimensions of rims on which the tire on  27  can be properly mounted. 
         [0034]    Identifiers  140 ,  141  are located on or embedded within rim  122  and preferably include information identifying characteristics of the rim, including the rim manufacturer, SKU number, model number, manufacturing date, rim dimensions, load limits, speed rating, and other identifiers indicating the identifiers, types, or dimensions of tires which can be properly mounted on rim  122 . 
         [0035]    Referring now to  FIG. 3 , wheel  114  is shown adjacent to side wall  150  of agricultural harvester vehicle  102 . Wheel  114  is shown in the straight-ahead position, which is the position the wheel assumes when the agricultural harvester  100  is traveling in a straight line over the ground. 
         [0036]    The left rear wheel  112  and its associated axle, drive, and steering components are constructed identically and function identically, but in mirror relation to right rear wheel  114 . 
         [0037]    The embodiment pictured here shows a telescopic axle member with a steering actuator disposed at the end. This is one embodiment. However, other axle steering and extension arrangements may alternatively be used. Alternative arrangements may include an axle that extends but not does not steer, or an axle that steers but does not extend. For an axle that steers but does not extend, the system is configured to automatically adjust the steering angle limits. For an axle that extends but does not steer, the system is configured to automatically adjust the axle extension limits 
         [0038]    Wheel  114  has an inside surface  152  and an outside surface  153 . The term “inside surface” indicates a surface of wheel  114  that faces generally inwardly toward the sidewall  150  of the agricultural harvester when the wheel  114  is mounted on the agricultural harvester. The inside surface  152  of wheel  114  can be an inside surface of tire  124  or of rim  122 . The term “outside surface” indicates a surface of wheel  114  that faces generally outwardly away from the sidewall  150  of the agricultural harvester when the wheel  114  is mounted on the agricultural harvester. The outside surface of wheel  114  can be an outside surface of tire  124  or rim  122 . 
         [0039]    Wheel  114  is bolted to a hub  154  that extends from the outer end of the axle  156 . A motor and gearbox  158  is fixed to hub  154  and rotates hub  154  about axis  128 . Motor and gearbox  158  may be driven by electricity or pressurized hydraulic fluid. 
         [0040]    A steering actuator  160  is fixed to hydraulic motor and gearbox  158  and is mounted on extendable axle member  162 . Steering actuator  160  may be driven by electricity or by pressurized hydraulic fluid. Steering actuator  160  pivots motor and gearbox  158  and hub  154  about a generally vertical axis  164 . 
         [0041]    Extendable axle member  162  is generally straight and elongate. It may be square, circular, rectangular, or polygonal in cross section. It is slidably supported in an outer telescopic axle portion  166  to permit it to slide in and out as the vehicle is being driven over the ground, thereby retracting and extending axle  156 . 
         [0042]    An actuator  168 , here shown as a hydraulic cylinder, is coupled to the chassis  116  and to extendable axle member  162 , and is configured to extend and retract extendable axle member  162  under computer control (not shown). Actuator  168  is shown here as a hydraulic actuator, preferably a hydraulic cylinder. It may alternatively be an electrically driven actuator, such as an electric motor driven ball screw. 
         [0043]    Referring now to  FIG. 4 , an electronic control circuit  170  is shown that is configured to steer the agricultural harvester vehicle  102  while holding the wheels as closely as possible to the left and right side walls  150  of the vehicle by extending and retracting the extendable rear axle members  162  on the left and right side of the vehicle using actuators  168  and by simultaneously steering the left and right rear wheels  112 , 114  left and right using actuators  160 ,. 
         [0044]    Electronic control circuit  170  includes a digital microcontroller  172  that is coupled to an operator input device  174  for receiving steering angle commands from the operator to steer the vehicle (device  174  is here shown as comprising a steering wheel). Operator input device  176  (here shown as a keyboard with a display), radio receiver  178 , and valve circuit  180  are also coupled to digital microcontroller  172 . A scanner  173  has a keyboard and display and is configured to electronically scan identifiers  136 ,  138 , 140 ,  141  and communicate the contents of the identifiers to digital microcontroller  172  via radio receiver  178 . 
         [0045]    Valve circuit  180  is provided with hydraulic fluid under pressure from hydraulic fluid supply  182  and returns hydraulic fluid to a low-pressure tank or reservoir  184 . Valve circuit  180 , in turn, is coupled to motors and gearboxes  158 , steering actuators  160 , and axle extending actuators  168  by hydraulic lines  186 . 
         [0046]    Valve circuit  180  is configured to direct the flow of hydraulic fluid to and from the actuators and motors to drive the wheels in rotation, as well as to steer them to the left and to the right from the straight-ahead position, and to extend them laterally away from and back toward the left and right sides of agricultural harvester vehicle  102 . Valve circuit  180  is configured to do this in response to commands from digital microcontroller  172  over signal lines  188 . 
         [0047]    Position and speed sensors disposed in pub  158 , steering actuator  160 , and axle extension actuator  168  transmit the wheel speed, steering angle, and axle extension to digital microcontroller  172  on signal lines  190 . 
         [0048]    During normal operation of the vehicle in the field or on the road, the operator turns the steering wheel of operator input device  174  to indicate a desired steering angle for the steerable rear wheels When the operator does this, the operator input device  174  transmits a signal indicating the desired steering angle to digital microcontroller  172 . The digital microcontroller  172  receives the signal and (1) calculates a desired degree of extension of extendable axles  162 ; and (2) calculates a desired steering angle. 
         [0049]    The farther the operator rotates the steering wheel, the farther digital microcontroller  172  turns wheels  112 ,  114  (by driving actuators  160 ) and by simultaneously extending the extendable axles  162  (by driving actuators  168 ) in order to maintain a narrow clearance between the innermost portion of wheels  112 ,  114  and left and right side walls  150  of vehicle- 102 . 
         [0050]    Digital microcontroller  172  is configured to steer the wheels  112 ,  114  as the operator turns the steering wheel until the steering angles of wheels  112 ,  114  reach predetermined steering angle limits. These limits are stored in the digital microcontroller  172  and are used as a reference by digital microcontroller  172  to prevent further steering of the wheels if the wheels (or other hub mounted equipment) would thereby hit the side wall  150  of the agricultural harvester. 
         [0051]    Using the present system, the operator does not have to manually calculate the steering angle limits for each axle extension position, or manually adjust mechanical steering stops or axle retractions stops when he changes, replaces or adjusts the tires or rims. 
         [0052]    Instead, the operator merely scans and transmits the data stored in or indicated by identifiers  136 ,  138 ,  140 ,  141  to digital microcontroller  172  when he changes or adjusts the wheels, tires, or rims. 
         [0053]    The digital microcontroller  172  is configured to receive this identifier data, determine the appropriate wheel  112 ,  114  steering limits and corresponding extendable axle member  162  positions, and then save these limits for use whenever the operator steers the vehicle. 
         [0054]    In one mode of operation, the operator operates scanner  173  to receive and transmit this data to digital microcontroller  172 . The operator moves to the rear of the vehicle, brings scanner  173  to the vicinity of the identifiers  136 ,  138 ,  140 ,  141  on the right rear wheel  114  and on the left rear wheel  112  and signals the scanner  173  to read the identifiers. Once the identifier data is gathered, the operator signals scanner  173  to transmit this data to digital microcontroller  172 . 
         [0055]    In another mode of operation, the operator gathers the data from the identifiers visually and types the data into the input device  176 , which provides the data to digital microcontroller  172 . 
         [0056]    In another mode of operation, the display provided on scanner  173  or on operator input device  176  is configured to instruct the operator which data to enter into the scanner  173  or operator input device  176  and in what order to enter it. For example, the scanner  173  indicates on its display that the operator is to scan data from the identifiers on the inside surface  152  ( FIG. 3 ) of the wheel (tire, rim, or both), or on the outside surface  153 . In this case, if the operator reversed the wheels  112 ,  114  such that their previously outwardly facing surface faced inwardly and their previously inwardly facing surface faced outwardly, this fact would be immediately determined by digital microcontroller  172 , since the operator would scan different identifiers once he reversed the wheels than he did when the wheels were in their previous position. 
         [0057]    In another mode of operation, the scanner  173  or operator input device  176  indicates on its display the order of scanning that the operator is to scan. For example indicating that the operator should first scan the identifiers  136  or  138  on the tire, and then scan the identifiers  140  or  141  on the wheel, (or vice versa). 
         [0058]    In another mode of operation, the scanner  173  or operator input device  176  indicates on its display that the operator is to first scan or enter data from the wheel identifiers (tire, rim, or both) on the left rear wheel and then from the right rear wheel, or vice versa. 
         [0059]    Once gathered and transmitted to the digital microcontroller  172 , the digital microcontroller  172  is configured to use the data from the identifiers, such as the size and geometry of the tires and wheels, to determine appropriate steering and axle extension limits. This process is illustrated in  FIGS. 5A ,  5 B,  6 A, and  6 B. 
         [0060]    Assume that an initial small wheel  114  is supported on an extendible axle  162  as shown in  FIG. 5B . The wheel  114  has a maximum steering angle of “B” for the particular extension of the extendable axle. This maximum steering angle is based at least partially on its small overall diameter “d”. 
         [0061]    When the illustrated wheel  114  is replaced with a larger wheel  114 , shown in  FIG. 5A , the smaller wheel has a smaller maximum steering angle “A” through which it can be steered for the same axle extension as shown in  FIG. 5B . This smaller maximum steering angle is based upon its larger overall diameter “D”. 
         [0062]    Digital microcontroller receives the data from identifiers  136 ,  138 ,  140 ,  141  and calculates the new reduced steering angles for each position of axle extension, and then limits the steering of wheel  114  to the reduced angle for all future steering actions. 
         [0063]    In  FIG. 6A , an extendible axle member  162  and wheel  114  are disposed adjacent to the side  150  of the combine vehicle. With the wheel  114  in this position, identifier  141  faces outward and identifier  140  faces inward. The axle  162  may be retracted until the side wall of the vehicle is at the position indicated by the dashed line  150 ′. 
         [0064]    The operator, having mounted wheel  114  in the position shown in  FIG. 6A  previously scanned the outwardly facing identifier on the wheel (in this case identifier  141 ). The operator then transmitted the data from identifier  141  to digital microcontroller  172 , and digital microcontroller  172  set the retraction limit of extendable axle member  162  such that the axle could be retracted until the side wall  150  of vehicle  102  is in the position indicated by line  150 ′. 
         [0065]    In this axle position, almost the entire steering actuator  160  is withdrawn into the side  150  of the vehicle as indicated by the overlap of line  150 ′ and the steering actuator  160 . Yet the vehicle  102  is not at risk since a slight clearance “c” is provided at this, the retraction limit of the axle  162 . 
         [0066]    The operator then removes and reverses the wheel  114  from its position shown in  FIG. 6A  to its position shown in  FIG. 6B . In  FIG. 6A , the outwardly facing identifier was identifier  141 . In  FIG. 6   b  the outwardly facing identifier is now identifier  140 . 
         [0067]    As described above, the mounting surfaces of the rim are offset with respect to the axis of symmetry  130  of wheel  114 . Therefore, if the digital microcontroller  172  retracts the axle member  162  of  FIG. 6B  to the same retracted position as  FIG. 6A  (indicated by dashed line  150 ′), then wheel  114  of  FIG. 6B  will be pulled by actuator  168  into the side of the vehicle. This is indicated in  FIG. 6B  by the overlap of line  150 ′ and wheel  114 . 
         [0068]    To prevent this, the system must change the axle retraction limit. In  FIG. 6B  extendable axle member  162  cannot be withdrawn as far as shown in  FIG. 6A . 
         [0069]    Instead, extendable axle member  162  can be withdrawn a reduced distance until only a small portion of steering actuator  160  is retracted into the side wall of the vehicle  102 . This reduced amount of retraction is indicated by the location of dash-dot line  150 ″ which represents the location of the side wall of the vehicle when the extendable axle  162  is retracted this reduced distance. In this position, a slight clearance “d” is provided between the inner surface of wheel  114  and side wall  150  of vehicle  102 . 
         [0070]    To ensure that extendable axle member  162  can only retract this reduced distance and thereby prevent wheel  114  from damaging sidewall  150 , digital microcontroller  172  is configured to automatically establish a new retraction limit. Digital microprocessor  172  calculates this new retraction limit based upon data received from identifiers  136 ,  138 ,  140 ,  141 . 
         [0071]    To establish this new retraction limit, the operator will first reverse the wheel  114  from the position shown in  FIG. 6A  to the position shown in  FIG. 6B . Once the wheel is reversed, the operator then scans the identifiers on the wheel. In this case the operator scans the (new) outwardly facing identifier  140 . 
         [0072]    Identifier  140  has different data than identifier  141  indicating reversed orientation of wheel  114 . Digital microcontroller  172  is configured to use this different data from identifier  140  and set the extendable axle retraction limit to that shown by line  150 ″ when the wheel is pointing straight ahead (i.e. the steering angle is 0 degrees). 
         [0073]    The identifiers may communicate digital data representing the actual dimensions of the tires and rims. Alternatively they may have model numbers, manufacturer names or SKU&#39;s that permit the digital microcontroller to look up the dimensions, either remotely over the internet, or by looking the data up in a lookup table or tables that associate these manufacturer numbers with specific dimensions. 
         [0074]    Regardless of the data that digital microcontroller  172  receives from the identifiers, it is configured to derive from the identifiers axle retraction limits that will prevent damage to the vehicle, and to also derive appropriate steering angle limits for each axle extension position. 
         [0075]    Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.