Patent Publication Number: US-2023134768-A1

Title: Header height control for combine harvester

Description:
FIELD OF THE INVENTION 
     The present invention relates to a system for adjusting a height of a header of a combine harvester based upon various factors. 
     BACKGROUND OF THE INVENTION 
     As is described in U.S. Pat. No. 7,222,474 to CNH America LLC (the &#39;474 Patent), which is incorporated by reference in its entirety and for all purposes, the height of a header of a combine harvester is capable of being adjusted. Header height is typically adjusted depending upon the type of crop being harvested by the combine. The header height is also adjusted to conform to the changing contours of the ground. More particularly, combines typically include ground contact sensors to detect the distance between the header or cutter bar and the ground. The height of the header is adjusted based upon the input of the ground contact sensors. It is envisioned that a combine harvester could also use forward-looking sensors to determine the contours of the ground lying ahead of the combine. 
     When the combine is travelling at high ground speeds it would be advantageous to use sensing inputs from the forward-looking sensors to provide advanced detection of ground contours. However, when the combine is travelling at slow speeds (e.g., 5 mph or less) while traversing aggressive ground contours, the forward-looking sensors may detect contour changes too far in advance and cause the header to move upward (or downward) prematurely, thereby resulting in sub-optimal harvesting. 
     For combines having forward-looking sensors and ground contact sensors, it would be desirable to weight the inputs of the forward-looking and ground contact sensors as a function of the speed of the combine. 
     It is noted that although various features (e.g., forward looking sensors of a combine) are described in the Background section, the inclusion of such features in the Background section is not an admission that such features represent prior art. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the invention, a combine harvester includes a header for harvesting crop material on the ground, a ground speed sensor configured to detect a ground speed of the combine, a ground height sensor configured to detect a contour of the ground located directly beneath the header, a forward looking sensor (FLS) configured to detect a contour of the ground forward of the header, and a controller. The controller is configured to receive signals from the ground speed sensor, the ground height sensor and the FLS, and calculate a header height output as a function of (i) an output of the ground speed sensor, which represents a ground speed of the combine, (ii) an output of the ground height sensor, which represents the contour of the ground located directly beneath the header, and (iii) an output of the FLS, which represents the contour of the ground that is forward of the header. The controller is further configured to weight the outputs of the ground height sensor and the FLS as a function of the speed of the combine harvester in calculating the header height output. 
     According to another aspect of the invention, a method for controlling a height of the header above the ground comprises: 
     receiving signals at a controller of the combine from the ground speed sensor, the ground height sensor and the FLS, 
     calculating a header height output, using the controller, as a function of (i) an output of the ground speed sensor, which represents a ground speed of the combine, (ii) an output of the ground height sensor, which represents the contour of the ground located directly beneath the header, and (iii) an output of the FLS, which represents the contour of the ground that is forward of the header, and 
     weighting, by the controller, of the outputs of the ground height sensor and the FLS as a function of the speed of the combine harvester in calculating the header height output. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG.  1    is a side view of a front end of an agricultural combine harvester having a header (with a cutter bar) in a raised position above the ground, the header including a ground sensing apparatus and a forward-looking sensor. 
         FIG.  2    is a simplified flow chart for header height control. 
         FIG.  3    is a detailed view of the steps for calculating ground speed shown in the flow chart of  FIG.  2   . 
         FIG.  4    is a graph showing the relationship between a weighting coefficient and ground speed. 
         FIG.  5 A  is a simplified plan view of a combine and the location of forward looking sensors on the combine. 
         FIG.  5 B  is another simplified plan view of the combine of  FIG.  5 A  shown in the course of moving or turning through a curve. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     For convenience of reference and understanding in the following discussions, and with respect to the various drawings and their descriptions, the point of reference for the use of various terms that are hereafter employed, including “left”, “right”, “forward”, “rearward”, “front”, “back”, “top”, and “bottom”, should generally be considered to be taken from a point at the rear of the combine harvester machine facing in its normal direction of travel, unless it is clear from the discussion and context that a different point of reference is appropriate. Any use of such terms should therefore be considered exemplary and should not be construed as limiting or introducing limitations. 
     Moreover, inasmuch as various components and features of harvesters and fan assemblies are of well-known design, construction, and operation to those skilled in the art, the details of such components and their operations will not generally be discussed in significant detail unless considered of pertinence to the present invention or desirable for purposes of better understanding. 
     In the drawings, like numerals refer to like items, certain elements and features may be labeled or marked on a representative basis without each like element or feature necessarily being individually shown, labeled, or marked, and certain elements are labeled and marked in only some, but not all, of the drawing figures. 
     Turning now to the drawings wherein a preferred embodiment of the invention is shown, in  FIG.  1   , a front end of an agricultural combine  10  is shown including a conventional header  12  supported on a feeder  14 , for cutting or severing crops such as, but not limited to, legumes such as soybeans and small grains such as wheat, and inducting the severed crops into feeder  14  for conveyance into combine  10  for threshing and cleaning as the combine  10  moves forwardly over a field. Header  12  includes a bottom or pan  16  which is supported in desired proximity to the ground surface of the field during the harvesting operation. An elongate, sidewardly extending cutter bar  18  supporting elongate, reciprocally movable sickle knives  20  (for example) is disposed along a forward edge of pan  16 . The cutter bar  18  severs the crop for induction into the header  12 . An elongate, sidewardly extending reel  22  is disposed above pan  16  and is rotatable in a direction for facilitating induction of the severed crops into header  12 . An elongate, rotatable auger  24  extends in close proximity to a top surface of pan  16  and has spiral flights therearound (not shown) which convey the severed crops to feeder  14  for induction into combine  10 . The front wheels  13  (or tracks) of the combine  10  are shown in  FIG.  1   . 
     Combine  10  includes a ground speed sensor  17  for sensing the ground speed of the combine  10  during operation. The ground speed sensor  17  may be a speedometer, GPS, or other speed sensing device of the combine  10 , as is known in the art. The ground speed sensor  17  may mounted or effectively mounted at the center axis G ( FIG.  5 A ) of the combine  10  to determine the ground speed at the center axis G. 
     Header  12  is shown including a ground height sensor  26  constructed and operable according to teachings of the present invention, for sensing or contacting the ground surface  28  of a field residing directly beneath the header  12 . The ground height sensor  26  is positioned either at or behind cutter bar  18 . The ground height sensor  26  is configured to provide information relating to (i) the contour of the ground  28  directly beneath the header, (ii) contact with the ground, and/or (iii) the height ‘H’ of the cutter bar  18  (or another point on the header  12 ) with respect to the ground  28  at the current position of header  12 , for example, to one or more controls of combine  10 , such as an automatic header height control (not shown), a feeder height and/or angle control (also not shown), and/or a header tilt control (also not shown). The aforementioned controls may be managed by one or more controllers, such as the controller  50  that is described herein. The ground height sensor  26  does not necessarily have to contact the ground, and, may be a non-contact sensor that may utilize LIDAR, RADAR, or SONAR, and/or ground sensor  26  may be ultrasonic sensor or camera. Further details of the ground sensor  26  are provided in the &#39;474 Patent. 
     A forwarding-looking sensor (FLS)  30  is mounted to header  12  for sensing the contours (e.g., height) of the ground  28  at a location forward of header  12 . FLS  30  may utilize LIDAR, RADAR, or SONAR, and/or FLS  30  may be ultrasonic sensors or cameras. While FLS  30  may sense the elevation of ground contours that are forward of header  12 , depending upon the type of FLS  30 , FLS  30  does not necessarily detect the longitudinal distance to those contours. As noted above, when the combine is travelling at high ground speeds it would be advantageous to use sensing input from FLS  30  to provide advanced detection of ground contours. However, when the combine is travelling at low speed (e.g., 5 mph or less) while traversing aggressive ground contours, FLS  30  may detect contour changes too far in advance and cause header  12  to prematurely move upward (or downward) or tilt about a center axis G of the combine  10  ( FIG.  5 A ), thereby resulting in sub-optimal harvesting. 
     FLS  30  and ground sensor  26  represent a “sensor pair,” and are positioned at the same lateral position along the length “L” ( FIG.  5 A ) of the header  10 . The header  12  includes at least one sensor pair  26 / 30 . The example shown in  FIG.  5 A , for example, includes four sensor pairs A, B, C and D positioned along the length L of the header  12 . Each sensor pair A-D includes one FLS  30  and one ground sensor  26 , for example. The header  12  may include any number of sensor pairs. 
     A motor  29  raises and lowers the feeder  14  as well as the header  12  that is connected thereto in a vertical direction, as is known in the art. Alternatively, motor  29  could raise or lower the header  12  independently of the feeder  14 . 
     Another motor or actuator  31  rotates (i.e., tilts) the header  12  about the center axis G ( FIG.  5 A ), as is known in the art, to compensate for uneven ground conditions. Specifically, a series of actuators  31  may be spaced apart along the length L of the header  12  for tilting the header  12 . 
     The combine  10  further includes a controller  50  that is configured to receive signals from the sensors  26  and  30 , and actuate the motor  29  and actuators  31  to raise, lower and/or tilt the header  12  based upon the signals from the sensors  26  and  30 , as will be described in greater detail with reference to  FIG.  2   . The controller  50  incorporates automatic header height control, a feeder height and/or angle control, and/or a header tilt control. 
       FIG.  2    is a simplified flow chart for header height control. The flowchart provides a method  200  for controlling the height of the header  12  relative to the ground  28 . It should be understood that the method  200  described hereinafter is performed for a single sensor pair  26 / 30  (i.e., sensors  26  and  30  of  FIG.  1   ), and the method  200  is repeated for every sensor pair  26 / 30  of the combine  10 . As noted above, the sensors of a sensor pair  26 / 30  are positioned at the same lateral position along the length “L” ( FIG.  5 A ) of the header  10 . Also, it should be understood that the output of the method  200  may also be used to control tilt of the header  12 . 
     According to the method  200 , at step  202 , the ground speed sensor  17  transmits the ground speed of the machine (i.e., combine  10 ) or data corresponding thereto to the controller  50 . At step  204 , the controller  50  calculates the steering curvature of the combine  10 . At step  206 , the controller  50  calculates the local ground speed at the location of the sensor pair  26 / 30  based upon the machine ground speed transmitted at step  202  and the steering curvature transmitted at step  204 . Steps  202 ,  204  and  206  comprises a process  205  for calculating the local ground speed at the location of the sensor pair  26 / 30 . The process  205  is shown in simplified form in  FIG.  2   , and in detailed form in  FIG.  3   . The process  205  will be described in greater detail with respect to  FIG.  3   . 
     At step  208 , the controller  50  determines a weighting coefficient W1 based upon the local ground speed at the sensor pair  26 / 30  calculated at step  206 . The weighting coefficient W1 is determined using an equation or look-up table, for example. An exemplary graph of such an equation is shown in  FIG.  4   . In  FIG.  4   , the equation is a non-linear, piecewise quadratic function, however, the equation could be linear (e.g., Y=X) without departing from the scope or spirit of the invention. Using any local ground speed (as determined at step  206 ), it is possible to calculate or identify a weighting coefficient W1 using the equation or look-up table. According to this example, the weighting coefficient W1 varies between 0.1 and 10, depending upon the local ground speed at the sensor pair  26 / 30 , however, these values could vary. 
     The cutoff speed is identified on the graph in  FIG.  4   . The cutoff speed is the speed of the combine at which the function plotted on the graph transitions from a decaying value to a substantially constant value. The cutoff speed may be 5 miles per hour, for example. At the cutoff speed, the weighting coefficient W1 is 0.1. The purpose of the weighting coefficient W1 will be described in greater detail with reference to step  214 . 
     At step  210 , the output of the ground sensor  26  of the sensor pair  26 / 30  is transmitted to the controller  50 . The output signal of the ground sensor  26  corresponds to the detected vertical distance (i.e., height) from the ground to the cutter bar  18  (for example). As noted above, ground sensor  26  is positioned either at or rearward of the cutter bar  18  of the combine  10 . 
     At step  212 , the output of the FLS  30  of the same sensor pair  26 / 30  is transmitted to the controller  50 . As noted above, FLS  30  is positioned forward of the cutter bar  18  of the combine  10 . The output signal of the FLS  30  corresponds to the ground height at some location forward of the sensor  30  (e.g., depending upon the type, configuration and resolution of the FLS  30 ). The output signal of the FLS  30  may be output, for example, as (i) a vertical distance between the current ground position and the ground that is forward of the sensor  30 , or (ii) a vertical distance between the cutter bar  18  and the location on the ground that is forward of the sensor  30 . The controller  50  is configured to manipulate the output signal, as required. 
     At step  214 , the controller  50  calculates the weighted header height output at the lateral location of one sensor pair  26 / 30  along the length L of the header  12  using the function of  FIG.  4    in combination with the output data of the sensors of that sensor pair  26 / 30 . Specifically, the controller  50  calculates a weighted header height output for each sensor pair  26 / 30  based upon the following formula: 
       Output=( W 1*Input1+(1/ W 1)*Input2)/( W 1+(1/ W 1)), where 
     Input1=header height value detected by ground sensor  26  of sensor pair  26 / 30  at step  210 ; 
     Input2=ground height value detected by FLS  30  of sensor pair  26 / 30  at step  212 ; 
     W1=weighting coefficient calculated at step  208 ; and 
     Output=weighted header height output at lateral location of sensor pair  26 / 30 . 
     The Output will vary depending upon the signals transmitted by the sensors  26  and  30 , the detected ground speed of the combine  10  transmitted by sensor  17 , as well as the detected steering curvature and the lateral location of the sensor pair  26 / 30  on the header  12  (as will be described with reference to  FIG.  3   ). 
     In calculating the Output, for speeds above the cutoff speed shown in  FIG.  4   , no weight (or very little weight) is given to the output of the ground sensor  26  of the sensor pair  26 / 30  whereas the output of the FLS  30  of the same sensor pair  26 / 30  is heavily weighted. Conversely, for speeds below the cutoff speed, in calculating the Output, no weight (or very little weight) is given to the output of the FLS  30  of the same sensor pair  26 / 30  whereas the output of the ground sensor  26  of the sensor pair  26 / 30  is heavily weighted. Accordingly, when the combine is travelling at slow speeds (e.g., 5 mph or less) while traversing aggressive ground contours, contours detected by FLS  30  of the sensor pair  26 / 30  do not cause header  12  to prematurely move upward (or downward) or tilt about axis G ( FIG.  5 A ), which would result in sub-optimal harvesting, because the output of FLS  30  is not weighted as heavily as the output of the ground sensor  26  of that sensor pair  26 / 30 . The different weightings are made possible due to the weighting coefficient W1, which changes the Output depending upon the speed of the combine  10 . 
     At step  216 , the Output, i.e., the weighted header height at the lateral location of sensor pair  26 / 30  is transmitted to controller  50 . 
     As noted above, method  200  is repeated for every sensor pair  26 / 30 . Thus, controller  50  will receive an Output at step  216  for every sensor pair  26 / 30 , which may include, for example, four different sensor pairs A-D, as shown in  FIG.  5 A . The controller  50  will then control the motor  29  and actuator  31  to raise, lower, and/or tilt the header  12  depending upon the output calculated at step  216  for every sensor pair  26 / 30  of the header  12 . 
       FIG.  3    is a detailed view of the steps of process  205  for calculating local ground speed at the sensor pair  26 / 30  while taking into consideration turning of the combine  10 . A turning operation executed by the combine  10  is shown in  FIG.  5 B . As background, when the combine is driving in a straight line, all of the sensors of the sensor pairs  26 / 30  output the same ground speed, however, when the combine  10  turns left or right, the sensor pairs  26 / 30  will output a different localized ground speed. As best shown in  FIG.  5 B , during operation, the sensor pair D will experience a lower local ground speed than the sensor pair A given their respective locations from the center of the turning radius. As will be described hereinafter, the controller  50  will take into account those different ground speeds upon calculating ground speed. It is noted that each sensor  26  and  30  of a particular sensor pair  26 / 30  will experience substantially the same ground speed during the turning operation of the combine  10 , however, the different sensor pairs  26 / 30  will experience different ground speeds during the turning operation, as detailed above. 
     At step  302 , the controller  50  detects the steering curvature of the combine  10 . The steering curvature of the combine  10  may be detected using a steering sensor or a GPS of the combine  10 , or other means known to those skilled in the art for detecting turning of the combine  10 . 
     At decision block  304 , the controller  50  determines if the curvature of the combine is zero (0), and if the answer to that question is ‘YES’, then the method proceeds to step  306 . At step  306 , the controller  50  sets the Gain to a numerical value of 1. The Gain is representative of the steering curvature, thus step  306  is representative of step  204  of  FIG.  2   . The method then proceeds to step  206 , at which point the controller  50  calculates the ground speed for the sensor pair  26 / 30 . The ground speed for the sensor pair  26 / 30 , which compensates for the turning radius of the combine  10 , equals the product of the Gain and the machine ground speed that is calculated at step  202 . For a combine  10  having a steering curvature of zero, the Gain is set to one (as noted above), thus, the ground speed for the sensor pair  26 / 30  is equal to the machine ground speed that is calculated at step  202 . In other words, for a combine  10  having a steering curvature of zero, the ground speed for the sensor pair  26 / 30 , which compensates for a non-existent turning radius, is simply equal to the machine ground speed that is calculated at step  202 . The process  205  is then complete for that sensor pair  26 / 30 , and the method  200  moves along to step  208  for that sensor pair  26 / 30 , as was described with reference to  FIG.  2   . 
     Referring back to decision block  304 , if the answer to the question at the decision block  304  is ‘NO,’ indicating that the combine  10  is executing a turning operation, then the method proceeds to step  308 . At step  308 , the controller  50  calculates the turning radius of the combine  10 . The value of the turning radius is 1/curvature. In differential geometry, the radius of curvature, R, (turning radius) is the reciprocal of the curvature. For a curve, the radius of curvature equals the radius of the circular arc which best approximates the curve at that point. Other ways of calculating the turning radius are known to those skilled in the art and may be used in performing the method  200 . At step  310 , the controller  50  calculates the radiussensor, which is the turning radius of the combine at the lateral location of the particular sensor pair  26 / 30 . To calculate the radiussensor, the controller  50  subtracts (i) the distance of the sensor pair  26 / 30  from the center ‘G’ of the combine (as shown in  FIG.  5 A ), which may be either a positive or negative value, from (ii) the turning radius calculated at step  308 . At step  312 , the controller  50  calculates a speed multiplier, which is the Gain, and which is equal to radiussensor divided by the turning radius calculated at step  308 . The Gain has a numerical value that is not equal to 1 (because the combine  10  is executing a turn). The Gain is representative of the steering curvature, thus step  312  is representative of step  204  of  FIG.  2   . 
     The method then proceeds to step  206 , at which point the controller  50  calculates the local ground speed for the sensor pair  26 / 30 . The local ground speed for the sensor pair  26 / 30 , which compensates for the turning radius of the combine  10 , equals the product of the Gain that is calculated at step  312  and the machine ground speed that is calculated at step  202 . The process  205  is then complete for that sensor pair  26 / 30 , and the method moves along to step  208 , as was described with reference to  FIG.  2   . 
     As noted above, process  205 , along with the other steps of method  200 , are performed for each sensor pair  26 / 30 . 
     It is to be understood that the above-described operating steps are performed by the controller  50  upon loading and executing software code or instructions which are tangibly stored on a tangible computer readable medium, such as on a magnetic medium, e.g., a computer hard drive, an optical medium, e.g., an optical disc, solid-state memory, e.g., flash memory, or other storage media known in the art. Thus, any of the functionality performed by the controller  50  described herein, such as the aforementioned method of operation, is implemented in software code or instructions which are tangibly stored on the tangible computer readable medium. Upon loading and executing such software code or instructions by the controller, the controller may perform any of the functionality of the controller described herein, including any steps of the aforementioned method described herein. 
     The term “software code” or “code” used herein refers to any instructions or set of instructions that influence the operation of a computer or controller. They may exist in a computer-executable form, such as machine code, which is the set of instructions and data directly executed by a computer&#39;s central processing unit or by a controller, a human-understandable form, such as source code, which may be compiled in order to be executed by a computer&#39;s central processing unit or by a controller, or an intermediate form, such as object code, which is produced by a compiler. As used herein, the term “software code” or “code” also includes any human-understandable computer instructions or set of instructions, e.g., a script, that may be executed on the fly with the aid of an interpreter executed by a computer&#39;s central processing unit or by a controller. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.