Abstract:
The automatic adjustment of a combine harvester ( 10 ) includes providing an electronic map with characteristics of the field (304), determining a work parameter of the combine harvester ( 10 ) by using information provided by the electronic map; and adjusting an actuator ( 36, 38, 42, 84, 48, 50 ) of the combine harvester ( 10 ) with the aid of the determined work parameter.

Description:
The invention relates to a system and method for setting the work parameters of an agricultural harvester. 
     BACKGROUND OF THE INVENTION 
     Agricultural harvesters are used to harvest the plants from a field. Processing operations take place in the harvester, so as to handle the crops for the purpose of a later further processing. Thus, the crops are chopped in a field chopper and threshed in a combine thresher, separated, and cleaned. In these processing operations, various work parameters of the harvester are set; with a field chopper, for example, the cutting length and, perhaps, an effective intensity of a conditioning device and with a combine harvester, the threshing drum speed, the threshing slit, the speed of the cleaning blower, and the sieve opening, and with all harvesters, the rate of advance that determines the individual throughput. 
     For most combine harvesters, basic settings for the work elements such as the threshing element, the residual grain separation, and the cleaning device are proposed as empirical values by the manufacturer. On the basis of the great variation of actual characteristics of the crops, these proposals can only be initial approximations. The only thing the operator still needs to do is to optimize the settings, depending on the available specifications (for example, crops with low losses or in the shortest possible time) and crop conditions, so as to be able to utilize the full performance capacity of the machine. That can take place in a purely manual manner according to its own strategy in a dialogue operation with assistance systems (see EP 2 165 591 A1), or automatically with an automatic adjustment system (EP 2 401 904 A2). A basic problem remains in that the dividing, separating, and cleaning operations in a combine harvester are very complex and their results can be monitored only by a few sensors. Even with so-called anticipatory sensors, no absolute relationship is yet recognizable, initially, to the partial operations in the combine harvester and its results. For this reason, various methods have been proposed in the past for the mathematical modeling of the processes, on whose basis a setting of the function elements can take place (neural networks, fuzzy controllers, regression models, and so forth). 
     All these models, however, must first be also coordinated with the individual harvesting conditions and goal formulations. They require a certain training phase. Furthermore, the sensors used in these processes must also first be calibrated so as to be able to provide reliable information. Proceeding from the settings found in the training phase, these systems can then compensate for variations in the harvesting conditions to a certain extent by adapting to the machine setting and the traveling speed. If the deviations are excessively large, these systems must also be recoordinated and the sensors must be recalibrated. These training phases and calibration require a certain time period during which the prevailing boundary conditions should be maintained as constant as possible. 
     The disadvantage exists, moreover, that feedback sensors interact with crops in the harvester, and for that reason, with changes in the characteristics of the gathered crops, reactions come much too late. In the state of the art, therefore, different procedures are described in which the attempt is made so that with an adjustment of the work parameters of the harvester, the characteristics of the crops to be harvested in each case are taken into consideration, in an anticipatory manner, by an automatic control. 
     In this respect, sensors are used, on the one hand, which, in an anticipatory manner, have a view of the crops from the harvester, so as to determine their characteristics (for example, density, maturity), and so as to change, with the aid of the determined characteristics, work parameters and settings of the harvester, such as the rate of advance (DE 101 30 665 A1). 
     On the other hand, methods are described in which an electronic map with field characteristics and/or operating data of the harvester is first set up, so as to recall the map data during the harvest in a georeferenced manner and to use them to set up work parameters of the harvester to be adjusted automatically. 
     DE 44 31 824 C1, for example, proposes that, in a first harvesting operation, the yield data for the grain and straw throughput, grain losses, and adjusted theoretical values of the operating parameters be stored in a map, in a georeferenced manner. In the next harvesting operation, the data from the map are recalled, in an anticipatory and georeferenced manner, so as to derive therefrom the individual working parameters of the harvester. The possibility of inserting a subordinate control loop thereby exists, which is based on a so-called reverse control action for the traveling speed, in which the individual throughputs of the combine harvester are locally recorded and used for the determination of the traveling speed, so as to obtain a constant throughput performance and/or constant settings of the work elements of the combine harvester. 
     DE 10 2005 000 770 B3 describes a procedure for the automatic control of a combine harvester, in which a theoretical map, which is used for the fundamental control of the combine harvester, is to be set up on the basis of georeferenced data obtained during the biomass development. During the harvesting operation, a regulation of the rate of advance and the setting of the work parameters of the combine harvester take place on the basis of the theoretical map so as to attain an acceptable threshing quality and losses. 
     With the anticipatory sensors, it has proved problematic to record sufficiently exact data at a distance that extends sufficiently far in front in order to take into account the reaction times of the actuators for the purpose of a prompt change of the work parameters of the combine harvester. Suitable sensors are thus relatively cumbersome and expensive. With the known systems based on georeferenced sensors, there is the problem that the actual harvesting characteristics are not always exactly in agreement with the characteristics predicted from the map, which can lead to inappropriate work parameters for the harvester. The subordinate control with a rear control action in accordance with DE 44 31 824 C1 reduces this problem, however, but there still remain inaccuracies in the data derived only from the map that make a local optimization of work parameters for the harvester and/or a calibration of feedback sensors, in particular the loss sensors, appear to be useful, but which is not provided for in the state of the art. 
     The goal of the invention under consideration is then seen as providing a system and a method for the automatic setting of processing parameters for an agricultural machine that does not have the aforementioned disadvantages or has them only to a lesser extent. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the invention, a method for setting work parameters for a harvester comprises: (a) providing a map with characteristics of a field in an electronic control device of the harvester; (b) deriving at least one work parameter of the harvester in a harvesting operation with the control device, taking into consideration a characteristic of the field, deduced from the electronic map for a harvesting position; (c) adjusting an actuator of the harvester, with the aid of the derived work parameter with the control device; (d) determination of a finely adjusted work parameter with the control device, with the aid of the result of step (b), taking into consideration a measurement value of a result of the harvesting operation that can be influenced by the actuation, determined with a sensor, and/or a connection, determined with the aid of an operator input, between a work parameter determined in step (b) and a work parameter that is to be adjusted, and the repetition of step (c) with the finely adjusted work parameter. 
     The proposal is made that (e) sections be identified along a path of the harvester, over the field, with the control device with the aid of the electronic map, on which characteristics of the field are homogeneous within predetermined limits and above a threshold value for distances lying above a threshold value for the length, and that (f) calibration data for the sensor and/or parameters for the fine adjustment of the work parameter and/or the operator input for step (d) be determined in the moving and harvesting of at least some sections identified in step (e) and be used in the following steps (d). 
     In other words, an electronic map is prepared in which characteristics of a field are recorded in a georeferenced manner. These characteristics can be soil characteristics (type of soil, soil moisture), topographical characteristics (height above sea level, angle of tilt, and alignment) and/or information from which the plant density of the field can be derived, such as data regarding the plant and/or usable part throughput from previous harvesting operations or data for the site-specific delivery of fertilizer from points of view of precision agriculture. In this respect, reference is made to the state of the art in accordance with DE 44 31 824 C1 and DE 10 2005 000 770 B3, whose disclosures are hereby fully incorporated in the documents under consideration. This electronic map can be set up on a stationary computer in an office or on a mobile computer or in the electronic control device of the harvester and is loaded, in step (a), in the work storage unit of the control device of the harvester. 
     In step (b), at least one work parameter of the harvester is derived by the control device during a harvesting operation, taking into consideration a characteristic of the field deduced from the electronic map for a harvesting position. Thus, during the harvesting operation, the position of the harvesting machine is determined, for which reason recourse can be had to a position-determining system, such as GPS, Galileo, Glonass, and/or an inertia measurement device, that makes use of a known satellite-based or earth-bound transmitter. For each position of the field to be processed (preferably in an anticipatory manner, so that upon reaching a certain position, the work parameter has already been correspondingly set), a characteristic of the field is read off the electronic map and, from that, an appropriate adjustment of a work parameter for the harvester is derived: in step (c), this work parameter is then adjusted with the control device, and for this reason, a suitable control signal is sent to an actuator of the harvester. 
     Since the electronic map does not reflect reality with sufficient precision in all cases, a fine adjustment of the work parameter determined in step (b) is carried out in step (d). A regulation of the work parameter can be carried out with the control device, which has recourse, as the feedback value, to a measurement value of a result of the harvesting operation that can be influenced by the actuator, as recorded with a sensor. Alternatively or additionally, the control device can undertake the fine adjustment in step (d) with the aid of a connection, determined on the basis of an operator input, between a work parameter determined in step (b) and a work parameter to be adjusted. Thus, one considers an operator input from which is derived a change (absolute or relative) of the work parameter determined in step (b). The operator input can, for example, state that the rate of advance or any arbitrary work parameter should be higher by a certain percentage than that determined in step (b). Step (c) is repeated with the now finely adjusted work parameter (regulated with the aid of the feedback value of the sensor or the operator input). Future passages through step (c), based only on the values from the electronic map, are omitted as soon as sufficient data for step (d) are available. The actuators are then adjusted only on the basis of the result of step (d). 
     Thus, for example, if the actuator controls the rate of advance and the sensor records the throughput in the harvester, for example, by measuring a driving force of a feed conveyor or a threshing drum, an expected throughput, determined in step (b) during the determination of the rate of advance, as the theoretical value to be attained, is compared to the actual throughput, and the advance rate is raised or lowered as compensation in the case of a deviation so as to obtain a desired theoretical value of the throughput. Analogously, the rate of advance is increased by the aforementioned percentage if the operator input is taken into consideration. In this case, there need not be recourse to sensors, but rather one obtains an open regulation loop whose theoretical value is corrected by the operator input. 
     However, since the sensors may work with insufficient precision and agricultural harvesters, in particular, combine harvesters, are complex systems that react in a relatively sensitive manner to harvesting conditions, the invention under consideration proposes that the control device identify, in one step (e), with the aid of the electronic map, sections along a path of the harvester over the field on which characteristics of the field are homogeneous within prespecified limits and over distances along that length that lie above a threshold value. Accordingly, sufficiently long partial distances of a path of the harvester to be traversed over the field are identified on which one or more characteristics are sufficiently similar or the same. Accordingly, these partial sections are particularly suitable for determining, in one step (f), calibration data for the sensor and/or parameters for the fine adjustment of the work parameter and/or the aforementioned operator input. These calibration data and/or parameters and/or operator input is/are determined during the traveling and harvesting of some sections that are to be identified in step (e) and used in the following steps (d). 
     An advantage of the use of georeferenced electronic maps is the possibility of estimating in advance the related size of areas with almost similar characteristics, and the limits of these areas. That makes possible a clear improvement of the dynamics and stability of control circuits. Thus, related large areas can be utilized, so as to calibrate sensors that coordinate the control models to the real conditions, or that undertake an adjustment optimization for this area. With smaller areas, the decision can be made, according to the control task, as to whether this area should be ignored (filtered) or whether an even more aggressive regulation must take place. In a similar manner, an anticipatory estimate can be carried out as to whether the transitions between various areas are more flowing or sharper, so that, likewise, the dynamics of the regulation can be correspondingly adapted there. 
     It is not the overriding goal of the invention to immediately derive direct indications from the electronic map data for the optimal adjustment of the machine. Rather, the areas with the same or similar characteristics and their limits are to be recognized. For the individual areas, an optimization by an internal control loop initially takes place. These found values can then be used to “train” the electronic map in a known manner. Another advantage is that a learning-capable, georeferenced electronic map can be built up as a framework for various control tasks in which the development expense is reduced. 
     In this way, the electronic map is not only used for the (anticipatory) adjustment of the work parameter of the harvester, but rather it is also used to identify sections of the harvesting path on which calibration data are determined for the sensor and/or parameters for the fine adjustment of the work parameter and/or the operator input, which are subsequently used for the automatic, precise fine adjustment of the work parameter. 
     In step (f), the calibration data and/or parameters for the fine adjustment of the work parameter for step (d) can be determined by an operator and input into the control device or can be automatically determined by the control device. 
     The work parameter can be, for example, the rate of advance of the harvester, a threshing device adjustment (rpm, threshing slit), a cleaning adjustment (blower rpm, sieve opening, the sieve vibration frequency) and/or a cutting mechanism adjustment (height, side tilt). 
     The sensor can be, for example, a grain loss sensor and/or a throughput sensor. 
     As described above, in step (d), differences can exist between a theoretical value for a work parameter derived only from the electronic map in step (b) and a measurement value determined by means of a sensor, which lead to the subsequent regulation of the work parameter. These differences can also be used to update the characteristics recorded in the electronic map and/or the pertinent position. 
     The parameters for the fine adjustment of the work parameter determined in step (f) can concern variables of mathematical models or of machine learning algorithms and/or the selection of a control strategy. 
     In step (d), there is the possibility that the electronic control device additionally takes into consideration the measurement value of an anticipatory crop sensor, for example, a camera, a radar sensor, or a laser scanner. 
     In order to avoid unnecessary adjustments of the actuator, in step (b), the control device can ignore changes of the characteristics of the field in the electronic map, if they are valid only over distances that fall short of a minimum value. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, an embodiment example of the invention, described in more detail, is shown below. 
         FIG. 1  is a schematic side view of an agricultural harvester, in the form of a combine harvester. 
         FIG. 2  is a flow chart that shows how a control device of the harvester of  FIG. 1  works. 
         FIG. 3  is an example of an electronic map that is used by the control device of the harvester. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a self-propelled harvester, in the form of a combine harvester  10 , with a chassis  12 , which is supported on the ground via front wheels  14  that are driven and rear wheels  16  that are steerable, and is moved forward by them. The front wheels  14  and the rear wheels  16  are turned by means of driving means, not shown, so as to move the combine harvester  10 , for example, over a field that is to be harvested. Below, direction indications, such as forward and backward, refer to the direction of travel V of the combine harvester  10  in a harvesting operation, which moves to the left in  FIG. 1 . 
     A harvesting attachment  18 , in the form of a cutting mechanism, is connected in a detachable manner to the front end area of the combine harvester  10  so as to harvest crops in the form of cereals or other threshable corn from the field during the harvesting operation, and to conduct them upward and backward through an inclined conveying assembly  20  to an axial threshing element  22 . The mixture containing grain and impurities, which passes through threshing baskets and grids in the axial threshing element  22 , arrives at a cleaning device  26 . Cereal that has been cleaned through the cleaning device  26  is conducted to a grain elevator by means of a grain auger; the elevator conveys it to a grain tank  28 . The cleaned cereal from the grain tank  28  can be unloaded by an unloading system with a cross auger  30  and an unloading conveyor  32 . The aforementioned systems are driven by means of a combustion engine and are controlled and steered by an operation from a driver&#39;s cabin  34 . 
     An electronic control device  54  controls (via valves that are not depicted) the position of an actuator  36  to change the height of the harvesting attachment  18  above the ground, controls the position of an actuator  38  to adjust the rpm of a blower  40  of the cleaning device  26 , controls the position of two actuators  42  to adjust the opening width of sieves  44  of the cleaning device  26  and controls an actuator  84  to specify the rate of advance of the combine harvester  10 . Another actuator (not shown), that is controlled by the electronic control device  54 , could specify the height of a reel of the harvesting attachment  18 . Furthermore, an actuator  48  controls the rpm of the axial threshing element  22  and an actuator  50  adjusts the position of the threshing basket so as to adjust the size of the threshing slit. The aforementioned actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50  are adjusted by the control device. 
     A throughput sensor  46  records the throughput in the inclined conveying assembly  20 , for example, with the aid of a driving torque of a chain conveyor of the inclined conveyor. A first grain loss sensor  52  records the quantity of the lost grains in the crop residue flow that is released by the axial threshing element  22  and is discharged through an ejection drum and, directly or via a straw chopper (not depicted), to the rear of the combine harvester  10 , onto the field. A second grain loss sensor  58  records the quantity of the lost grain in the crop residue flow that is released by the upper sieve of the cleaning device  26  and is discharged through the aforementioned straw chopper or a separate chaff distributor onto the field. The sensors  46 ,  52 , and  58  are connected by means of a transmission of signals to the electronic control device  54 . 
     The electronic control device  54  is also connected to a storage device  64 , a position determining device  62 , in the form of an antenna to receive signals from a satellite-based position determining system, and to an operator interface  68  with input means (buttons) and a display. 
       FIG. 2  shows a flow chart that shows how the electronic control device  54  of the combine harvester  10  proceeds while harvesting a field. In step  100 , an electronic map for the pertinent field is loaded into the storage device  64 . In this electronic map, georeferenced data for characteristics of the field are stored. An example of such an electronic map is shown in  FIG. 3 . It contains position-referenced characteristics of the field  304 , in which, for example, we are dealing with the type of soil and/or the yield measured in the last harvest. These characteristics are classified in a total of  6  classes in the electronic map shown. Furthermore, the electronic map contains topographical data of the field  304  (height data or height lines  300 ). This electronic map can be produced during the previous harvest by the combine harvester  10 , with the aid of data of the throughput sensor  46  and (three-dimensional) position data, by the position determining device  62  itself and remain after that in the storage device  64 , or it can have been transmitted by a computer, wirelessly (via a radio connection) or via a storage electronic map, into the storage device  64  in an arbitrary manner (for example, from another combine harvester or with the aid of aerial photographs or by a reconnaissance flight or aircraft, or with the aid of data for the precision-agricultural cultivation of the field) by an external computer. 
     In addition, a planned path  302  that the combine harvester  10  will traverse during the harvesting on the field  304  is stored in the storage device  64 . In this respect, reference can be made to known routing procedures. 
     In step  104 , the electronic control device  54  determines the actual position of the combine harvester  10 , with the aid of the signal of the position determining device (step  102 ) and derives from that a position that the combine harvester  10  will reach in a predetermined time (for example, in  2  seconds). This anticipatory procedure is advantageous because of the reaction times of the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50 . With the aid of the determined position, the electronic control device  54  deduces the pertinent characteristic of the field  304  from the electronic map, and from that, derives suitable work parameters of the combine harvester  10  and, derived from that, adjustment values for the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50 . For example, with the aid of a crop density that is stored in the electronic map, an expected throughput is calculated as the work parameter, and from that, the rate of advance of the combine harvester  10  is derived for the purpose of controlling the actuator  84 . In an analogous manner, the adjustments of the other actuators  38 ,  42 ,  84 ,  48 ,  50  can be determined. The steps  100  and  102  for the georeferenced preparation of the data from the electronic map (and perhaps the derivation of the work parameter in step  104 ), on the one hand, and the determination of the adjustment values for the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50  in steps  104 ,  106 , and  116 , on the other hand, can take place in various processes (or processors) of the electronic control device  54 . 
     The adjustment of the actuator  36  and perhaps a (not shown) actuator for the adjustment of the side tilt of the harvesting attachment  18  and/or perhaps, separately, for the compensation for a side slope of front wheels  14  that are height-adjustable is determined with the aid of the topographical data of the electronic map (see WO 2008/088916 A1). From the values derived from the topographical data for a side tilt of the combine harvester  10  on the side slope and/or a tilt of the combine harvester  10  in the forward direction, signals for the adjustment of the actuators  42  for the adjustment of the sieve opening can also be derived. 
     The steering of the combine harvester  10  during the harvesting operation is carried out manually by the operator of the combine harvester with the aid of the path  302  that is stored in the electronic map and the starting signal of the position determining device  62 , either automatically by means of a steering actuator (not depicted) for the adjustment of the steering angle of the rear wheels  16  or a display on the operator interface  68 . 
     In step  106 , the individual work parameters or the adjustment values derived from them by the electronic control device  54  are transmitted to the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50 , so that they automatically arrive at the position determined, in each case, by the electronic control device  54 . 
     Step  108  follows, where the query is made whether a recalibration of the electronic control device  54  is required or useful. Such a recalibration is particularly suitable if the combine harvester  10  reassumes its work (in the morning), when a field with a crop different from the previous one will be harvested or if a certain time has elapsed since the last recalibration, since crop characteristics change over the progressing time of day, in particular when exposed to sunlight. The recalibration is used to provide a fine adjustment of the combine harvester  10  so as to be able to adapt the work parameters stipulated in step  104  even more precisely to the individual conditions. 
     If a determination is made in step  108  that a recalibration is not required, then step  114 , which is explained in detail further below, follows. Otherwise, step  110  follows, in which the electronic control device  54  tests whether the partial section of the path  302 , traversed in the following, has a sufficiently long distance (lying above a threshold value of, for example, 100 m) that has, within limits, a constant characteristic, preferably including the topography. This ensures that during step  112  that may follow, sufficiently homogeneous conditions prevail, so as to attain reproducible results and thus suitable data for the fine adjustment. The topography can hereby also be taken into consideration, since the crops surely have different characteristics on north slopes than on south slopes. If the section is not suitable, then step  114  follows, otherwise, step  112 . 
     In step  112 , then, the aforementioned data are obtained for the fine adjustment. For the purpose, the combine harvester  10  is first moved over the field at a predetermined speed or a speed leading to a certain throughput (sensor  46 ), preferably over partial stretches of the path  302  that was completely identified in step  110 , or a part thereof. After the processing operation in the combine harvester  10  has stabilized, a calibration of the grain loss sensors  52  and/or  58  can, for example, take place, either with a loss testing bowl (see DE 101 50 080 A1) or a count of the grains behind the combine harvester  10  by the operator or by means of an image processing system (DE 10 2012 223 434 A1, whose disclosure is incorporated in the documents under consideration by reference). 
     Alternatively or additionally, the operator can examine one or more results of the work process, such as the purity of the grain in the grain tank  28  or the composition of the returns, and by means of the operator interface  68 , give corresponding inputs to the electronic control device  54 . In this respect, reference is made to the disclosures of EP 1 297 733 A1 and EP 1 371 278 A1. The electronic control device  54  then derives a new connection between the characteristic of the field, known from the electronic map, and the work parameter, which is used later in step  114 . There is also the possibility that the operator simply inputs an additive correction value or multiplicative correction factor if he is not satisfied with a specification of the control unit for a work parameter. Thus, the operator can raise or lower, by means of the operator interface  68 , for example, the rate of advance or the adjustment value for one of the other actuators  36 ,  38 ,  42 ,  48 ,  50  by a few percent or by concrete absolute values if the throughput or another result of the work process does not correspond to his expectations. Finally, step  112  can also be based exclusively on data obtained by the electronic control device  54 , in that it uses sensor values to adjust one or more work parameters more precisely. Thus, for example, the broken grains in the grain elevator can be determined by means of a camera or a UV sensor and can be used for the determination of a new connection between the characteristic of the field, known from the electronic map, and the work parameter (here: threshing element rpm and slit). 
     The data obtained in step  114  for the fine adjustment can also concern variables of mathematical models for the regulation of work parameters, for example, a mathematical model for the adjustment of the actuators  38 ,  42  for the cleaning device  26 . There is also the possibility that the aforesaid data concern variables of machine learning algorithms, for example, of neural networks and/or the selection of a control strategy—that is, for example, a switch between the throughput regulation and a loss-based regulation. 
     In step  118 , the query is then made whether step  112  has concluded—that is, a sufficient number of data were obtained for the fine adjustment. There is then the possibility of repeating step  112  on another path section on which the same or other characteristics of the field are valid. If other characteristics are valid, the possibility exists of obtaining a second set of data for the fine adjustment for these characteristics that can be correlated with these other characteristics. Data for the adjustment with intermediate values of the characteristics can then be produced, immediately or later, by interpolation. If the result of step  118  is that finding the data for the fine adjustment has not yet been concluded, then step  110  follows, once more, otherwise, step  114 . 
     In step  114 , there is a fine adjustment of the work parameters that were previously determined in step  104  with the aid of the electronic map. Initially (if the recalibration of steps  108  to  112  has not yet been carried out for the determination of the data for the fine adjustment), the data from step  104  are simply used. After the end of the recalibration, on the other hand, the data for the fine adjustment from steps  108  to  112  are used so as to find, with the aid of the work parameters from step  104  and the data for the fine adjustment, an improved determination of the work parameters and to transmit them or the adjustment values derived from them to the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50 . Accordingly, in step  114 , the starting values of the grain loss sensors  52 ,  58  can be improved with the aid of the calibration values found and can be used for the automatic regulation of work parameters of the combine harvester  10 . Analogously, values of the throughput sensor  46  can be calibrated and thus be more precisely recorded. As described above, the connections between the characteristics of the field  304  in the electronic map, also determined in step  112 , and the optimized work parameters to be adjusted can also be used for the adjustment of the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50 . The now attained adjustments are more precise than the adjustments based on step  104  and lead to better work results. 
     In step  116 , the query is subsequently made whether the electronic map is sufficiently precise. If there are no greater deviations between the work parameters from step  104  and the work parameters from step  114 , the electronic map is sufficiently precise and step  104  again follows in order to determine one or more work parameters for the next position of the combine harvester  10  along the path  302 . Step  106  is thereby skipped over after the end of the recalibration, because the finely adjusted work parameters are directly adjusted in step  114 . 
     If, on the other hand, step  116  shows that the electronic map is not sufficiently correct, the electronic map is corrected in step  120 . Thus, for example, a more imprecise throughput value in the electronic map can be replaced by a throughput value recorded by means of the throughput sensor  46 , or an average value from a throughput obtained in the electronic map and recorded by the throughput sensor  46  is input. There is also the possibility of shifting limits between adjacent classes, if, with the aid of values of a sensor or the position determining device  62 , they have not proved correct. Again, step  104  follows step  120  (with a changed electronic map, step  100 ). 
     During steps  104  to  114 , information regarding the steps carried out individually by the electronic control device  54  is displayed to the operator on the operator interface  68  by the electronic control device  54 . Furthermore, if it is useful, instructions regarding the steps to be carried out by him are displayed to the operator—for example, if he is to count the number of lost grains on a specific area and he is to input it in the electronic control device  54  via the operator interface  68 . If necessary, the combine harvester  10  can stop automatically to make it possible for the operator to carry out required actions that are displayed to the operator on the display unit of the operator interface  68 . In addition, the electronic map can be displayed on the display unit of the operator interface  68 , analogous to the representation in  FIG. 3 , wherein the individual position of the combine harvester  10 , the path to be traversed  302 , and the corresponding classification and actions to be carried out while traversing the path (calibration, etc.) can be particularly stressed. Also, adjustments for the actuators  36 ,  38 ,  42 ,  84 ,  48 ,  50  selected from the electronic control device  54 , values derived from signals of the sensors  46 ,  52 ,  58 , and/or arbitrary work parameters of the combine harvester  10  can be displayed on the display unit of the operator interface  68  by the electronic map. 
     What remains to be noted is that various modifications of the method in accordance with the invention are conceivable. Thus, after a recalibration, steps  106 ,  108 ,  114 , and  116  are skipped over if the change of the adjustment would take place only over a relatively short distance that lies below a threshold value, such as on the lower right edge of the electronic map of  FIG. 3  with the turning loops  306  in the headland. Furthermore, in steps  104  and/or  114 , the starting signal of an anticipatory sensor  60 , which can be a camera for the recording of the plant density ahead of the combine harvester  10 , can be used for the production of more precise work parameters, so as to compensate for stochastic variables which could not be foreseen with the aid of the electronic map, such as damage caused by game, destruction by insects, or stored cereals.