Abstract:
An arrangement for the automatic adjustment of the cut height of a front harvesting attachment on a harvesting machine for the harvesting of stalk-like plants. A controller is connected to a sensor and to an actuator that can adjust the cut height of the front harvesting attachment based on the detection by the sensor of at least one characteristic of the harvested crop material and can be repositioned as a function of the signal of the sensor.

Description:
BACKGROUND  
       [0001]     1. Field of the Invention  
         [0002]     The invention concerns an arrangement for the automatic adjustment of the height of cut of a front harvesting attachment on a harvesting machine for the harvest of stalk-like plants.  
         [0003]     2. Related Technology  
         [0004]     Forage harvesters are used primarily for the harvest of grass, corn or other forage plants. While pick-ups that are guided at a constant height above the ground by touch contact are used in harvesting of grass, the use of corn heads or cutter heads is common practice as the front harvesting attachment for forage harvesters in the harvesting of corn or the whole plant silage of cereal crops. The height of cut of such front harvesting attachments for the cutting of stalk-like crops can be varied.  
         [0005]     In the state of the art, the height of cut is provided as an input by the operator of the forage harvester and is controlled automatically by the control arrangement with the use of sensors and actuators. In such a way, a predetermined height of cut or a predetermined contact pressure of the front harvesting attachment is maintained. In the case of the input of the height of cut contradictory interests must be considered. On the one hand, the cut height of the front attachment of a forage harvester has a considerable effect upon the yield per unit area and the length of the remaining stubble on the field. On the other hand, it also affects the quality of the mass of forage produced where a low cut height is less desirable in the light of the optimization of the quality. Ground particles, such as sand particles, adhering to stalks (for example, stalks of corn plants) can considerably increase the wear of cutting tools on front harvesting attachments and of following machine components such as chopper arrangements. Due to cost considerations, it may not be in the interests of the operators of such forage harvesters to utilize the lowest cut height. On the other hand, plowless farming (in connection with direct sowing) is gaining considerable significance. This, in turn, demands the least possible length of stubble and, hence, the lowest cut height. Thus, the operator of the forage harvester is confronted by the problem of finding the optimum cut height associated with the immediate case.  
         [0006]     Moreover, the harvest of high energy silage, that is, corn with a high proportion of corn cobs, the harvested crop must be cut at a relatively great height above the ground. Here, the operator must see to it that the plants are cut as close as possible underneath the corn cobs themselves. A manual re-adjustment of the cut height does not, as a rule, lead to optimum results over large time intervals.  
         [0007]     DE 102 25 098 A proposes that the cut height used in each case be detected by measurement technology and to log the cut height with a geographical reference. This, however, does not assist the operator in the selection of the appropriate cut height.  
         [0008]     It has also been proposed that various properties particularly the nitrogen and protein content of a cereal crop be analyzed by means of an appropriate sensor during the harvest of the cereal crop with a combine. As a result of the analysis, the cereal crop is loaded into differing containers. EP 0 732 740 A, WO 03/029792 A and “Protein Mapping of Spring Wheat using a Mobil Near Infrared Sensor and Terrain Modeling”, Corey Grant Meier, M. Sc. Thesis, Montana State University, Bozeman, Mont., USA, April 1004, all relate to this concept. Also, an analysis of the material contents on board a forage harvester is described in DE 199 22 867 A. In this reference, the results of the analysis are merely mapped.  
         [0009]     The problem underlying the invention is seen as the need to simplify for an operator of a forage harvester the adjustment of the cut height.  
       SUMMARY  
       [0010]     The invention proposes that the cut height of the front harvesting attachment be controlled automatically as a function of a measured characteristic of the plants being harvested. The characteristic is detected by means of an appropriate sensor (for example, an optical sensor that preferably operates in the near infrared region in reflection or transmission mode) arranged at any desired location in the material flow. The characteristic of the plants detected by the sensor may be an amount of a material contents of the plant such as the contents of protein, nitrogen or energy or a magnitude previously stored in memory or of contaminants (for example, earth or sand). In the latter instance, it becomes possible to reduce the amount of contaminants in the harvested forage and thereby to increase the quality. Simultaneously, the work load on the operator is reduced and an inexperienced operator can deliver a good operating outcome.  
         [0011]     Various strategies or target inputs may be programmed into the controller connected to the adjustment assembly, according to which it controls adjustment as a function of the signals of the sensor. One or more value inputs may be provided as permanent input or may be selected by the operator. One possible target value input could be to hold the proportion of contaminants in the forage to a minimum value. If this target value input is selected, the height of cut is raised until contaminants are limited to a defined threshold value (that is a level of permanent input or an input that can be selected) or no contaminants exist in the harvested plants. Another possible target value input could be a maximum proportion of fiber attained in the forage. In this instance the controller would lower the height of cut as far as possible based on the target value. In this case, a combination could be selected for the target value input with respect to the contaminants, that is, the height of cut is lowered until a defined limit value, or one that can be provided as input, is reached for the contaminants contained in the forage. Another possible target value input could be the maximum energy contents of the forage, where the energy contents can be provided as input by the operator or be pre-defined. Thereby certain qualities of the forager can be attained automatically. Other target value inputs can also be combined in any manner desired. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Further features and advantages of the invention will become readily apparent to persons skilled in the art after a review of the following detailed description of a preferred embodiment, with reference to the appended drawings, which shows:  
         [0013]      FIG. 1  shows a schematic side view of a harvesting machine with an arrangement for the adjustment of the cut height of a front harvesting attachment; and  
         [0014]      FIG. 2  shows a pattern for the adjustment of the height of cut of the front harvesting attachment.  
     
    
     DETAILED DESCRIPTION  
       [0015]     A harvesting machine  10 , shown in  FIG. 1  in the form of a self-propelled forage harvester, is supported by a frame  12  that is carried by driven front wheels  14  and steerable rear wheels  16 . The harvesting machine  10  is controlled from an operator&#39;s cab  18  from which a front harvesting attachment  10 , appropriate for harvesting stalk-like plants, can be controlled visually. In the shown embodiment, the front harvesting attachment  20  is a corn picker head operating independently of rows. It conducts crop taken up from the ground (for example, corn, cereal crop or the like) to a chopper drum  22 , by means of upper pre-pressing rolls  30  and lower pre-pressing rolls  32 , where it is chopped into small pieces and delivered to a conveyor arrangement  24 . The crop leaves the harvesting machine  10  to an accompanying trailer (not shown) over a discharge arrangement  26  whose position can be adjusted. A post-chopper reduction arrangement  28  is located between the chopper drum  22  and the conveyor arrangement  24 , and through which the crop to be conveyed is conducted tangentially to the conveyor arrangement  24 . The invention can also be applied to other harvesting machines that process stalk-like crops, for example corn balers.  
         [0016]     The front harvesting attachment  20  and the intake housing  34  of the harvesting machine  10  that carries it, in which the pre-pressing rolls  30  and  32  are also arranged, are supported in bearings free to pivot about the axis of rotation of the chopper drum  22 . The pivoting of the front harvesting attachment  20  about this axis of rotation is performed by an actuator  36  in the form of a hydraulic cylinder. The pivoting of the front harvesting attachment  20  also provides for the adjustment of the cut height of the front harvesting attachment  20 ; that is, the height at which it cuts off the plants from the stubble remaining in the ground. The hydraulic cylinder is connected in joints at one end to the frame  12  and at the other end to the intake housing  34 . Such an actuator  36  may be provided on both sides of the intake housing  34 .  
         [0017]     The actuator  36  is single acting, or it may be double acting, and may be connected, so as to carry hydraulic fluid to a pump  42  or a reservoir  44  over a valve arrangement  40  (see  FIG. 2 ). The valve arrangement  40  is controlled electromagnetically by a controller  38 . The controller  38  and the elements for repositioning the actuator  36  as described here are provided as ongoing production components on harvesting machines. A feedback sensor (not shown) can transmit a signal to the controller  38  regarding the immediate position of the actuator  36  or the pivot angle or the intake housing  34  about the axis of rotation of the chopper drum  22 . The controller  38  is, in particular, the machine controller that also controls other functions of the harvesting machine.  
         [0018]     The controller  38  is connected with a sensor  46  and an input and display arrangement  48 . The sensor  46  is arranged on the upper side of the discharge arrangement  26 . It operates in the near infrared region and directs a broadband light on the chopped plants in the discharge arrangement  26  and resolves the light reflected by plants into spectra by means of wavelength dispersion elements (grating or the line). The reflected spectra is detected by appropriate light sensitive detectors detected in specific wavelengths. An appropriate sensor is described by U.S. Pat. No. 6,421,990, whose contents is incorporated into the present document by reference.  
         [0019]     The sensor  46  detects several properties of the chopped plants, particularly their material contents or one more values derived therefrom. The material contents of particular interest are organic material components, such as amylum, enzyme soluble organic substances (ElosT), oil and raw protein, and the proportions of these components in the harvested crop. In additional, the contents of non-organic components such as mineral components (ash), example, sodium and magnesium, contaminants in the form of sand (silicon dioxide) and earth, water and the color of the plants can be measured.  
         [0020]     Parameters of the harvested crop that are detected, in addition or alternatively to the material components, or that can be derived therefrom are the contents and the raw fiber contents of the harvested crop. The raw fiber contents and the fiber length can be determined, in particular, by further processing of the output signals of the sensor  46  by means of a program running in the controller  38 .  
         [0021]     The controller  38  has available, on the basis of the signals of the sensor  46 , information and similar data regarding the protein contents, the energy content and the proportion of contaminants in the chopped plants. The operator in the operator&#39;s cab  18  can read the actual magnitudes of these values at any time by means of the input and display arrangement  48 . The input and display arrangement  48  makes it possible for the operator to select the height of cut of the front harvesting attachment  20 , on the basis of which target value the controller  38  is to adjust. In addition, this target value can be provided as input or selected from among several inputs. During the harvesting operation the controller  38  controls the actuator  36  on the basis of signals of the sensor  46  in such a way that the target value inputs are maintained. Thereby a certain energy content or protein content in the forage is attained or a predetermined degree of contamination is not exceeded. By way of inputs into the input and display arrangement  48 , the operator can vary the target values at any time and, if useful, manually override the outputs of the controller  38  in order to raise the front harvesting attachment  20  in time to avoid a collision with an obstacle, for example. A conventional sensor for determining the height above the ground of the front harvesting attachment and/or the contact pressure of the cutter head upon the ground may also be connected with controller  38 . The controller  38  utilizes the signals of this sensor in order to prevent the front harvesting attachment  20  from being lowered too far, positions in which, for example, it could penetrate the ground.  
         [0022]     The measurement results of the sensor  46  and the cut height at the time are geographically referenced and stored in memory by the controller  38  for later evaluation, for example, for subsequent fertilization. In this way the height of the stubble remaining on the field can be considered as plant food input in a fertilizer calculation.  
         [0023]     As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from the spirit of this invention, as defined in the following claims.