Abstract:
A crop width measuring assembly is mounted to a harvesting assembly of an agricultural machine for measuring the actual width of the crop swath received by the harvesting assembly. The crop width measuring assembly comprises a plurality of crop presence sensors distributed along the width of the harvesting assembly. The crop width measuring assembly is in communication with a processor for monitoring different crop parameters in relation to their geographic location in a field.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to a crop width measuring assembly for measuring the width of crop received by a harvesting assembly of an agricultural machine. 
     BACKGROUND OF THE INVENTION 
     Crop management decisions are increasingly based on the information presented in yield maps. Thus, it is important that they are accurate and contain as few errors as possible. However, two systematic errors occur in existing methods of producing yield maps caused by difficulties in defining the start and end of cutting and knowing the crop width entering the agricultural machine. In order to produce error-free yield maps it is necessary to have an accurate and reliable method of detecting the start and end of harvesting and the width of newly harvested material entering the agricultural harvester. 
     One existing method of detecting the start and end of cutting is to monitor whether the harvesting assembly is raised or lowered (U.S. Pat. No. 5,524,424 A, EP 0 960 558 A). However, its accuracy depends on the operator&#39;s ability to lower and raise the table at a constant distance from the edge of the standing crop. Other methods have been used for measuring crop flow, but as currently conceived they are unreliable. 
     Some harvesters have a set of buttons that allow the operator to record the proportional width of the harvesting assembly being full of crop. If the operator does not use these buttons consistently and accurately, then it will cause further errors (S. Blackmore and M. Moore, Remedial Correction of Yield Map Data, Precision Agriculture, 1999, Kluwer, Vol. 1, pages 53-66). 
     An automatic measurement of the swath width by means of ultrasonic sensors and a determination of the effective harvest area from combine position data generated using GPS is discussed by K. Sudduth et al, Ultrasonic and GPS Measurement of Combine Swath Width, ASAE Annual International Meeting, Orlando, Fla., USA, 12-16 Jul. 1998, ASAE Paper No 983096. 
     In EP 0 960 558 A, a method for generating yield maps is proposed, in which the presence of crop to be harvested in front of a harvesting assembly is indicated by a sensor monitoring the position of the reel on the combine&#39;s harvesting platform. Additionally, ultrasonic distance sensors measure the width of the harvested crop swath. Thus, on both side ends of the harvesting assembly, ultrasonic distance sensors submit ultrasonic waves to the swath, and the swath width is determined based on the run time of the ultrasonic waves. This method does not work reliably when two swaths with a space between them are taken up. In addition, the ultrasonic sensors do not work when the crop is lodged. 
     DE 195 43 343 A discloses a baler in which the volume of received crop is measured by a capacitive sensor. DE 40 41 995 A proposes a forage harvester in which presence of crop throughput is detected by means of a capacitive sensor. According to the signal of the sensor, the rotational speed of the chopping drum of the forage harvester is controlled, or conservation chemicals are added to the harvested crop. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an apparatus for establishing a yield map having improved precision and reliability. 
     To accomplish this objective, a number of crop presence sensors are distributed over the width of a harvesting assembly of the agricultural machine. Preferably, the crop presence sensors are evenly distributed along the width of the harvesting assembly. It would also possible to have an uneven distribution. Each one of the crop presence sensors is capable of detecting whether crop is present in its detection range. The size of the detection range depends on the type of the crop presence sensor. It is possible to use crop presence sensors having a relatively large detection range, such as ultrasonic sensors covering a part of the width of the harvesting assembly, or to use crop presence sensors with a relatively small detection range. The latter only detect crop passing in their vicinity. According to the signals of the crop presence sensors, the crop width measuring assembly is operable to establish information regarding the width of the crop actually being received by the harvesting assembly. The actual swath width can be calculated by adding the width of the detection ranges of the crop presence sensors detecting crop (when the detection range is relatively large), or by multiplying the distance between adjacent sensors with the number of sensors detecting crop. 
     An advantage of the present invention is that cheaper and more reliable sensors can be used, since the distance between a sensor and the edge of the crop swath is not measured—like in the prior art, EP 0 960 558 A—but rather only the presence or absence of crop is detected. When the number of crop presence sensors is sufficiently high, the accuracy of the crop width measuring assembly is comparable with, or even higher than, the accuracy of known ultrasonic sensors for measuring swath width. Furthermore, the crop width measuring assembly according to the present invention is capable of detecting actual swath width when two swaths having a gap are received by the harvesting assembly. 
     Possible errors in the established swath width could be due to crop remaining in the detection range of the crop presence sensors. Such crop should not influence the information provided by the crop presence sensors. In order to resolve this problem, it is proposed to arrange the crop presence sensor such that moving crop removes (wipes) any stationary crop away from the crop presence sensors. This can be achieved when the outer surface of the crop presence sensor is located in the plane of the surface of the table of the harvesting assembly. 
     Alternatively or additionally, the signals from the crop presence sensors can be electronically processed by means of a signal processor to remove the effect of any stationary crop actuating the crop presence sensor. Thus, the output signal of the crop presence sensor can be time differentiated and afterwards submitted to a comparator or Schmidt-Trigger. 
     Capacitive sensors are preferably used as relatively cheap and compact crop presence sensors having a small detection range. They also work in conditions when crop is lodged. 
     The crop width measuring assembly of the present invention can be used in conjunction with a processor for collecting data concerning additional crop parameters. The processor is provided with a geographic position sensor, such as a GPS sensor and/or a speed sensor. In order to establish accurately the crop parameters with the geographic location, information regarding the crop swath width is necessary. The swath width sensor of the present invention establishes this information. Thus, the disadvantages of conventional hectare counters—dependence on position of the header and unknown swath width, see U.S. Pat. No. 5,524,424 A—are avoided. 
     Preferably, the apparatus for collecting data is operable to establish a yield map. Thus, an additional crop parameter sensor measuring a parameter of the crop received (such as weight per time or moisture content) is delivered to the processor. From this data, the processor establishes a map representative of the parameter at several locations of the field. This parameter can be the weight of the received crop per area, which is calculated according to the measured received weight per time, the swath width and the speed or position of the agricultural machine. The area is calculated using the signals from the crop width measuring assembly. Hence, errors in the yield map due to unknown swath width—as described above—are avoided. 
     The signals from the crop presence sensors can also be used to determine whether crop is received at all, and thus yields information defining the start and end of the harvesting cycle. An accurate definition of when harvesting starts and stops is as important as measuring crop width in producing an accurate yield map. Unless at least one crop presence sensor indicates the presence of crop, the yield established by the processor is considered as zero. 
     The present invention can be used in any type of harvesting assembly used on any type of agricultural machine. Preferably, it is used on a combine, wherein the crop presence sensors are distributed over the active width of a cutter bar of the harvesting assembly for a combine. It could also be used in a forage harvester, the sensors distributed over the width of the forage harvester harvesting assembly. Use of the invention on other harvesting assemblies such as mowers and any other agricultural machine processing, receiving, taking up or harvesting crop is also possible. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a semi-schematic side view of an agricultural combine. 
     FIG. 2 is a top view of the harvesting assembly for the combine. 
     FIG. 3 is a cross sectional view of the harvesting assembly. 
     FIG. 4 is a cross sectional view of a crop presence sensor embedded into the table of the harvesting assembly. 
     FIG. 5 is a cross sectional view of a crop presence sensor located above the upper surface of the table of the harvesting assembly. 
     FIG. 6 is a cross sectional view of a crop presence sensor located below a stone ridge on the harvesting assembly. 
     FIG. 7 is a cross sectional view of a crop presence sensor integrated into the stone ridge of the harvesting assembly. 
     FIG. 8 is a top view of the harvesting assembly for the combine with another embodiment of crop presence sensors. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 shows an agricultural combine  10  with a chassis  12  which is supported and propelled by ground engaging wheels  14 . Although the combine  10  is illustrated as being supported and propelled on ground engaging wheels  14  it can also be supported and propelled by full tracks or half tracks. A harvesting assembly  16  is used to take up crop and to conduct it to a feederhouse  18 . The crop is conducted by the feederhouse  18  to a beater  20 . The beater  20  guides the crop upwardly through an intake transition region  22  to a rotary threshing and separating assembly  24 . Although the invention is described in conjunction with a rotary combine, it can also be applied to other types of combines (for example conventional combines having a transverse threshing cylinder and straw walkers or combines having a transverse threshing cylinder and rotary separator rotors) or other agricultural machines. In addition, although the illustrated harvesting assembly is a harvesting platform the present invention can be used on other harvesting assemblies including flex cutterbar harvesting platforms, row crop headers, corn headers, pickup platforms and other harvesting assemblies. 
     The rotary threshing and separating assembly  24  comprises a rotor housing  26  and a rotor  28  arranged in the rotor housing  26 . The harvested crop enters the rotor housing  26  through the intake transition region  22 . The rotary threshing and separating assembly  24  threshes and separates the harvested crop. Grain and chaff fall through grates at the bottom of the rotor housing onto a cleaning assembly  34 . The cleaning assembly  34  removes the chaff and conducts the clean grain to a grain elevator  36  which conducts upwardly to a distributing screw conveyor  38 . The distributing screw conveyor  38  deposits the clean grain in a grain tank  40 . The clean grain in the grain tank  40  can be unloaded through an unloading auger  42  into a trailer or truck. Threshed straw separated from the grain is conducted out of the rotary threshing and separating assembly  24  through an outlet to a discharge beater  46 . The discharge beater  46  ejects the straw out the rear of the combine  10 . 
     The operation of the combine  10  is controlled from an operator&#39;s cab  48 . A geographic position sensor in the form of a receiver  50  for the reception of GPS signals (global positioning system) is attached above the operator&#39;s cab  48 . Although it is at least in principle not necessary, when the accuracy of the receiver  50  is sufficient, a speed sensor measuring the speed of the wheels  14  can be provided. Mounted on one side of the clean grain elevator  36  is a capacitor moisture sensor  52  for measuring the moisture content of the clean grain. Such a sensor is disclosed in DE 199 34 881 A. A mass flow sensor  54  is located at the outlet of the clean grain elevator  36 . The mass flow sensor  54  comprises an impeller plate mounted for rotation about a horizontal axis. Its deflection is dependent upon the mass flow rate of the clean grain. The deflection of the impeller plate is measured and thus data on the mass flow rate of the harvested grain is provided. Such a sensor is described in EP 0 853 234 A and the documents recited therein. 
     A processor  56  located in the operator&#39;s cab  48  (or somewhere else on the combine  10 ) is connected to the GPS receiver  50 , the moisture sensor  52 , the mass flow sensor  54 , and the speed sensor, when present. The processor  56  is provided with an internal clock or receives external time signals, for example from the receiver  50 . The processor  56  records the amount of harvested grain (measured by means of the mass flow sensor  54 ) and its moisture content (measured by means of the moisture sensor  52 ) dependent on the geographical position of the combine  10  (measured by means of the GPS receiver  50 ). The processor  56  logs the data and produces a field summary. Thus, it is possible to create a yield map with the logged data. 
     In order to reduce errors when generating the yield map, the harvesting assembly  16  is provided with a swath width sensing assembly, shown in FIG.  2 . The swath width sensing assembly submits data to the processor  56 , preferably by means of a bus, cables, optical fibers or electromagnetic waves. Thus, the actual width of the harvested swath is measured and considered when the yield map is generated. The processor  56  is informed when the swath of harvested crop is narrower than the active width of the header  16 , which might happen at an end of a field, or when the combine  10  passes certain parts of a field a second time. The processor  56  is capable of calculating a correct yield, since the latter depends on the amount of harvested grain and on the area on which it was harvested. This area depends on the actual swath width measured by the swath width sensing assembly. 
     The harvesting assembly  16  comprises cutter bar  58  for cutting the crop and an auger  60  for feeding the cut crop to the center of harvesting assembly  16 , where the harvested crop is fed into the feederhouse  18 . The cutterbar  58  and the auger  60  are positioned between left and right side sheets  61 . Crop dividers  62  are located at the front of the side sheets  61 . The dividers  62  are driven into the crop splitting the crop sideways in front of the harvesting assembly  16  before it is cut by the cutter bar  58 . The dividers  62  define the active width of the harvesting assembly. Although not shown, a conventional reel is usually located above the cutter bar  58 . 
     The front of the harvesting assembly  16  behind the cutter bar  58  is provided with a number of crop presence sensors  64  for detecting the presence of crop. These sensors  64  are distributed along the width of the harvesting assembly  16 . The crop presence sensors  64  submit data containing information whether crop is in their detection range (or not) to the processor  56 . In the embodiment shown in FIG. 2, six crop presence sensors  64  are evenly distributed over the active width of the harvesting assembly  16 . A swath of crop to be harvested is indicated with reference numeral  66 . Since in FIG. 2 the two uppermost crop presence sensors  64  (the most left sensors in the forward moving direction of the harvesting assembly  16 ) are not within the swath width, they will provide the processor  56  with a signal indicating the lack of crop. The three crop presence sensors  64  shown in FIG. 2 below the two uppermost crop presence sensors  64  are within the swath width. Thus, they submit a signal to the processor  56  indicating that crop is presently harvested at their location. Finally, the lowermost crop presence sensor  64  shown at the bottom of FIG. 2 (the most right sensor in the forward moving direction of the header  16 ) is outside the swath width, as well, and submits a corresponding signal to the processor  56 . 
     The crop presence sensors  64  distributed over the active width of the header  16  thus provide information on the actual width of the harvested crop swath to the processor  56 . According to the information provided by the crop presence sensors  64 , the processor  56  can determine the actual width of the swath  66 . The processor  56  is also operable to detect whether harvesting is performed and thus whether crop is received at all (when at least one crop presence sensor  64  gives an information that crop is present) or not (when no crop presence sensor  64  submits data indicating that crop is present). Thus, a sensor for detecting if the harvesting assembly is raised or lowered is superfluous, and disadvantages of such sensors, as inaccuracy, are avoided. 
     In FIG. 3, a vertical cross sectional view of the harvesting assembly  16  is given. A crop presence sensor  64  is located at the rear end of the table  74  of the harvesting assembly  16 . Sensor  64  is embedded into the surface of the table  74 . An alternative position of a crop presence sensor is indicated with  64 ′. Crop presence sensor  64 ′ is embedded into a stone ridge  76  at the forward end of the table  74 , behind the cutterbar  58 . 
     Preferably, the crop presence sensors  64  are capacitive sensors. Such sensors are available from Carlo Gavazzi Industri A/S, Over Hadstenvej 38, 8370 Hadsten, Denmark, order number EC 5525PPAP. An embodiment of a capacitive crop presence sensor  64  is shown in more detail in FIG.  4 . The crop presence sensor  64  is embedded into the upper surface of the table of the harvesting assembly  16 . The crop presence sensor  64  comprises a conductive foil  70  or plate mounted below an insulating (but not necessarily transparent) window  68  lying in the plane of the upper surface of the table  74  of the harvesting assembly  16 . The foil  70  is electrically connected to a signal processor  72 . When crop is present above the window  68 , the electric capacitance of the foil  70  measured against the header alters (increases). The signal processor  72  measures the electric capacitance of the foil  70 . For example, the foil  70  is part of an electric resonance circuit, the resonance frequency of which is measured. Any other measurement of the capacitance is possible, as well. The signal processor  72  thus provides information regarding the presence of crop in the crop presence sensor&#39;s  64  vicinity to the processor  56 . 
     In order to avoid crop resting on the window  68  from triggering the crop presence sensor  64 , producing an error of the yield map, the crop presence sensor  64  is positioned on the table  74  of the harvesting assembly  16 . Hence crop remaining on the window  68  is normally wiped away by harvested crop passing across the table  74 . Alternatively or additionally, the output of the signal processor  72  is electrically processed removing the effect of any stationary material actuating the crop presence sensors  64 . Thus, a time derivation of a value representing the electrical capacitance of foil  70  can be obtained and further processed. 
     In FIG. 5, another embodiment of a capacitive crop presence sensor  64  is given. It is located above the surface of the table  74  of the harvesting assembly. A ramp  78  in forward direction before and behind the crop presence sensor  64  keeps the surface of the crop presence sensor free of stationary material. 
     FIG. 6 shows a third embodiment of a crop presence sensor  64 , located below the stone ridge  76 , and FIG. 7 represents a fourth embodiment of a crop presence sensor  64 , integrated into the stone ridge  76 , like the crop presence sensor  64 ′ in FIG.  3 . The elements of the crop presence sensors  64  of FIGS. 5 to  7  are the same as those of the sensor shown in FIG.  4 . 
     For either position  64  or  64 ′ shown in FIG. 3, it is possible to make use of separate crop presence sensors  64  as indicated in FIG.  2 . In another embodiment, shown in FIG. 8, two arrays of crop presence sensors  64  are provided. A first array of crop presence sensors  64  is placed at the left-hand edge of the table  74 . A second (optional) array of crop presence sensors  64  is placed against the right-hand end of the table. This arrangement of sensors operates like the one disclosed in FIG. 2, except when the swath width does not cover the sensor array or arrays the processor  56  records the width as zero. Both arrays of crop presence sensors  64  preferably cover a width of 0.2 to 1.0 m. Software is used to insert the missing data on the yield map by interpreting between adjacent runs where the table was nearly full. Thus, the yield is known more accurately than with the embodiment of FIG. 2, although a similar number of crop sensors  64  is used. 
     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.