Abstract:
A method, a controller and a vehicle for performing agricultural operations on a field with parallel arranged rows having ends. The operations are performed at positions related to the positions of the rows under control of the controller, based upon stored information about the orientation of the rows, stored information about a distance between adjacent rows, a distance signal related to a distance traveled by the vehicle and a direction signal related to the heading of the vehicle. The invention is particularly suited for providing dams to prevent water from a head ditch to enter into pre-selected, dry furrows on a field with an irrigation arrangement with raised rows and lower furrows between the rows, or dams matching up with adjacent raised rows so that water runs down each furrow.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method, a controller and a vehicle for performing agricultural operations on a field with rows having ends, the rows being generally parallel to each other. 
     BACKGROUND OF THE INVENTION 
     There are a number of agricultural operations to be performed at ends of rows on a field. Such rows are in the most cases arranged in parallel and the distances between the rows are equal or at least similar. 
     A first example of such an operation is to deposit and collect boxes into which workers put vegetables or fruit harvested from plants grown in the rows. Another example is maintenance of an irrigated field. Such fields can comprise parallel raised rows and parallel lower furrows between the rows. Plants are grown on the raised rows, while the water is allowed to flow in a number of the furrows for watering the plants. A common situation is to flow water between alternating raised rows to conserve water and prevent waterlogging. However, other arrangements can also be made. A head ditch provided at the end of the field and extending generally perpendicular to the rows and furrows contains water for the field and needs thus to be connected to those furrows into which water is to flow. 
     One method of controlling which furrow(s) are to have water flowing into them is to create dams between the head ditch and those furrows that are to be kept dry. The other furrows are, due to lack of a dam between them and the head ditch, connected to the head ditch and get watered. These dams are called rotobucks and produced with a dedicated type of implement (also called a rotobuck) that is pulled by a vehicle, usually a tractor, and scrapes ground material together when the vehicle is moving. The implement is triangular shaped with a point on each triangle tip that penetrates into the ground and builds up a mound of ground material along a curved edge of one side of the triangle, which will become the dam. A latch holds the tool in place as the vehicle pulls it around the field. When the latch is released, the tool rotates, depositing the ground material that has been built up along the curved edge of the triangle, and then rotating the tool to the next side, where another mound of ground material is built up for subsequent deposit. 
     In the prior art, the latch, which is hydraulically moved, is controlled manually by the operator of the tractor, by a suitable interface within the operator cabin. The position where, or the time when, to release the latch is critical to ensure that the dam is deposited in the proper location. Often, a second person is used to watch the position of the rotobuck device in the field and tell the tractor driver when to release the latch. When the correct position is missed, the operator or the second person needs to use a shovel to rebuild the dam at the correct location. Thus, manual control of the rotobuck device is a difficult and time consuming task. Additionally, the dams may need to be rebuilt every time it is necessary to go into the field with other devices, like sprayers, since they are normally destroyed or damaged by these other devices. This may happen several times during a growing season. 
     Automatically controlled arrangements for providing the dams are available, that steer the tractor along the head ditch, while software controls the implement to provide the dams. However, since these arrangements rely on a single spacing of the dams, a problem arises when the angle between the head ditch and the rows varies over a field, since this angle has an impact on the correct spacing between adjacent dams. 
     Since many fields are not completely rectangular in shape, especially at field ends, there is a need for a simple and reliable system for automatically performing agricultural operations on a field with parallel arranged rows having ends that are not all at the same angle to the head ditch. 
     It is an object of the present invention to provide a simple and reliable system for automatically performing agricultural operations on a field with parallel arranged rows having ends, such that the operations are automatically performed at desired locations related to the positions of the rows with respect to the head ditch. 
     SUMMARY OF THE INVENTION 
     A method of performing agricultural operations on a field with parallel arranged rows having ends comprises propelling a vehicle past the ends of the rows and performing agricultural operations at the ends of the rows with an implement connected to the vehicle at desired positions related to the positions of the rows under control of a controller device. The controller controls the implement based upon stored information about the orientation of the rows, stored information about a distance between adjacent rows, a distance signal related to a distance traveled by the vehicle and a direction signal related to the heading of the vehicle. 
     The distance between adjacent operations depends on the distance between adjacent rows. If the angle between the propelling direction and the longitudinal direction of the rows is not perpendicular, the distance between the operations needs to be adjusted accordingly in order to ensure that they are performed at the desired locations with respect to the rows. The controller therefore derives this angle from a direction signal containing information about the heading direction of the vehicle and stored information on the orientation of the rows, for example their angle enclosed with the north-south direction. An adapted distance between operations is calculated and the implement is controlled based upon this distance and a distance signal related to a distance traveled by the vehicle. 
     An advantage of the invention is that a spacing of adjacent dams can be automatically adjusted to compensate for non-perpendicular paths across the rows, such that the vehicle can be operated in all field shapes. The automated spacing of the dams will ensure that the manual repairs that are required with imperfectly spaced dams will be minimized. Also other operations, such as automated depositing and collecting boxes from ends of rows, can be performed with high precision. 
     The angle between the rows and the heading of the implement can be derived by the controller from the stored information about the orientation of the rows and from the direction signal related to the heading of the vehicle. The latter, like the distance signal, can be derived from a location signal generation arrangement generating location data of the position of the vehicle and/or the implement. This location signal generation arrangement can be a Global Positioning System (GPS) or Differential Global Positioning System (DGPS) antenna mounted on the vehicle or on the implement, or a GPS or DGPS antenna mounted on both of them, or some other arrangement or types of devices, as appropriate. 
     The controller is preferably connected to an operator interface. The operator of the vehicle can input at least one of the following into the operator interface: information about the orientation of the rows, information about the distance between adjacent rows, information about a desired distance between adjacent operations, information about an offset between the positions of the location signal generation arrangement and the implement, information about a desired location of a first operation, information about the dimensions of the implement, and fine adjustment data for the positions on which the operations are performed. The input data is stored in memory and the controller uses the stored information for controlling the implement. 
     In a preferred embodiment, the method and system is particularly suitable for providing dams on irrigated fields, having an irrigation arrangement with raised rows, lower furrows between the rows, and a transverse head ditch in the vicinity of the ends of the furrows. The implement is depositing ground material at the desired locations in order to provide dams between the head ditch and raised rows to prevent water from the head ditch from entering into pre-selected, dry furrows. The dams can in another embodiment be positioned to match up with each raised row so that water runs down each furrow. Of course, parts of a field can have parts with dams watering alternating furrows and other parts on which dams match with the raised rows such that all furrows are watered. The implement (rotobuck) is scraping ground material together when the vehicle is moving, and the controller is controlling the implement to release the ground material at the desired location to build a dam. These and other objects, features and advantages of the present invention will become apparent to one skilled in the art upon reading the following detailed description in view of the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a vehicle with an implement and a controller for controlling the implement; 
         FIG. 2  is a schematic top view of an irrigated field, on which the vehicle of  FIG. 1  can provide dams; and 
         FIG. 3  is a flow diagram according to which the controller of  FIG. 1  works. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In  FIG. 1 , a vehicle  10 , shown in this case in the form of a tractor, and an implement  12  mounted behind the tractor are shown. The vehicle  10  has an operator&#39;s cab  20 , in which a steering wheel  22  for steering the vehicle, and pedals and/or levers (not shown) for inputting a desired speed of the vehicle  10  are located. On board the vehicle  10 , a controller  26  is located. The controller  26  is connected to a memory  28 , an operator interface  30  in the cab  20 , and to a first location signal generation arrangement  32  mounted on the roof of the cab  20  and comprising an antenna for receiving signals from a satellite-based positioning system like GPS, Glonass or Galileo. 
     At the rear end of the vehicle  10 , a three point hitch  34  comprising an upper draft linkage  36  and two lower draft linkages  38  is used to connect implement  12  to the vehicle  10 . The linkages  36  and  38  are adjustable to adjust the vertical position of implement  12  during operation and to lift it when desired. 
     The implement  12  comprises a frame  40 , below which and to a tool  54  is mounted. In a preferred embodiment of the invention, tool  54  comprises three blades  56  radially extending from a central shaft  58 , offset to the adjacent blade  56  by 120° and at their ends (and between them) interconnected by supporting disks  84 . Shaft  58  is connected to beams of the frame  40  and rotatably supported by suitable bearings (not shown). The blades  56  have forwardly curved outer tips  62  that are suited to scrape and collect ground material in front of the blade  56  when vehicle  10  is propelled forward, as can be seen at the mound of ground material  64  shown in  FIG. 1 . Rotation of shaft  58  and blades  56  is selectively inhibited by a latch  66  that can be moved by an actuator  68  in the form of a double acting hydraulic cylinder between an operative position blocking rotation of shaft  58  and blades  56 , as shown in  FIG. 1 , and a lifted operative position (not shown), allowing rotation of shaft  58  and blades  56  in order to release mound  64  to build a dam at a desired location. Actuator  68  is mounted to the frame  40 . 
     On top of the frame  40 , a second location signal generation arrangement  70  comprising an antenna for receiving signals from a satellite based positioning system like GPS, Glonass or Galileo is provided. The second location signal generation arrangement  70  and a valve assembly  86  control the actuator  68 , and are connected to controller  26 . These connections, like the connections between controller  26 , operator interface  30  and first location signal generation arrangement  32 , can be provided by a bus or wirelessly by radio connection. Valve assembly  86  is connected to the hydraulic system of vehicle  10 . 
     An irrigated field  72  is shown in  FIG. 2 . On the field  72 , a number of parallel raised rows  74  and lower furrows  76 ,  78  are provided. The rows  74  and furrows  76 ,  78  have ends in the vicinity of a head ditch  80 . On the rows  74 , plants are grown, while the furrows  76  are dry, and the furrows  78  are filled with water from the head ditch  80 . Furrows  76  and  78  are arranged in an alternating manner in the embodiment shown in  FIG. 2 . In order to prevent water from entering into furrows  76  to conserve water and prevent waterlogging, dams  82  are provided, which extend transversely to the head ditch  80  and build, in cooperation with the raised rows  74  adjacent furrow  76 , a barrier to prevent the water in the head ditch  80  from entering furrows  76 . 
     These dams  82  are also known as “rotobucks”, like the implement  12 , and produced with the vehicle/implement combination shown in  FIG. 1 . In another embodiment of an irrigated field (not shown), the dams  82  match up with each raised row  74  so that water runs down each furrow  76  and  78 . As can be seen in  FIG. 2 , when the head ditch or edge of a field as a curve, angle or other bend, the dams  82  have to change shape and/or the angle to the head ditch  80  in order to be properly aligned to the raised rows  74  so as to allow or prevent water from running into the furrows  76 ,  78 . 
     In order to overcome difficulties in accurately releasing latch  66  manually from cab  20  at the appropriate time to get the dam  82  to the desired position in which it blocks water from entering the adjacent furrow  76  (or in the other embodiment, matches up with row  74 ), controller  26  proceeds according to the flow diagram of  FIG. 3 . 
     The process begins at step  100 . In step  102 , one or more of the following types of information is input into memory  28 , typically by means of an operator interface: (a) Information about the orientation of the rows  74 . This can be the angle of the rows  74  with respect to the north-south direction or within any coordinate system. It would also be possible to drive the vehicle  10  along a row  74  and to derive the information about the orientation of the rows  74  from one of the location signal generation arrangements  32  and  70 , telling the controller  26  via the operator interface  30  that the vehicle  10  is now driving along a row  74 . (b) Information about the distance between adjacent rows  74 . It would also be possible to store a map of field  72 , including location and orientation of one, two or all the rows  74 , in memory  28  and to derive this distance and/or the orientation of the rows  74  from this map. (c) Information about the desired distance between adjacent dams  82 . This can be a value in meters or any other length unit, or data about the number of rows  74  between adjacent dams  82 , which would in the example of  FIG. 2  be two (and in the other embodiment, in which the dams  82  match up with the rows  74 , one). (d) Information about the offset between one of the location signal generation arrangements  32  and  70  and the position of the dam  82  when latch  66  is raised. Here, it might be useful also to input data about the dimensions of the tool  54 . (e) Further, information about the location of the first dam  82  to be made can be input in terms of geo-referenced coordinates. In another embodiment, the controller  26  would receive an input via operator interface  30  once the vehicle  10  is in a position where the first dam  82  needs to be deposited. 
     In the following step  104 , the vehicle  10  is driven by the operator, or when it is already on the field, optionally by an automatic steering system, close to the location of where the first dam  82  should be placed, for example the rightmost dam  82  in  FIG. 2 . Some distance before this location is reached, implement  12  is lowered by means of hitch  34  and/or linkages  36 ,  38  such that a blade  56  with tip  62  has built up a mound  64  when the location of the first desired dam  82  is reached. 
     Then, in step  106  the system determines, based upon the information about the location of the first dam  82  (from step  102  ( e )) and/or the information about the offset between one of the location signal generation arrangements  32  and  70  and the position of the dam  82  when latch  66  is raised (from step  102 , ( d )), and/or data from one or both of the location signal generation arrangements  32  and  70  whether the location for depositing the dam  82  has been reached. 
     In step  108 , when it is determined that the position for depositing the dam  82  has been reached, controller  26  instructs actuator  68  to lift latch  66  such that the collected ground material is deposited, and dam  82  is built. As already mentioned, alternatively, instead of steps  106  and  108 , the operator can drive vehicle  10  to the location of the first dam  82  and inform the controller  26  by means of the operator interface  30  accordingly. In the other embodiment (not shown), in which the dams  82  match up with the rows  74 , the first dam would be aligned with a first row  74 . 
     In step  110 , vehicle  10  is driven along the head ditch  80  towards the next dam  82  and after a short distance, actuator  68  is lowered again in order to build up a new mound  64  of ground material. The vehicle  10  is driven under control of the operator or automatically by the controller  26  according to a stored map and signals from one or both of the location signal generation arrangements  32  and  70 . 
     In step  112 , the required distance between the last dam  82  and the next dam  82  is calculated. For this calculation, first of all the distance between adjacent dams when driving the vehicle  10  perpendicular to the rows is determined, based upon the information (b) and (c) from step  102 . In the example of  FIG. 2 , this distance would be twice the distance between adjacent rows  74 , since every second furrow  76  from furrows  76 ,  78  gets no water. In the other embodiment, in which the dams  82  match up with the rows  74 , this distance would correspond to the distance between adjacent rows  74 . It should be noted that if the desired distance between the dams  82  is directly inputted in step  102 , the distance between adjacent rows  74  would not have to be inputted here. The former distance already contains information about the distance between the rows  74 , from which the distance between dams  82  depends. 
     Since the vehicle  10  is driven along the head ditch  82 , the dams  82  are oriented perpendicular to the head ditch  82 , but not necessarily perpendicular to the rows  74  and furrows  76 ,  78 . Due to trigonometric effects, this has an impact on the distance between the adjacent dams  82 , as can be seen in  FIG. 2 , where the dams  82  at the left end are spaced further apart than those at the right end of the drawings. The required distance between the dams  82  is proportional to 1/cos α, α being the angle between the heading of the vehicle  10  and the longitudinal direction of the rows  74 . Thus, this angle α is calculated in step  112  from the information (a) of step  102  and a direction signal related to the heading of vehicle  10 , which is taken from one or both of the location signal generation arrangements  32  and  70 . In another embodiment, the direction signal can be taken from a compass or an inertial navigation system or derived from a map according to the position of the vehicle measured by at least one of the location signal generation arrangements  32  and  70 . Hence, in step  112  the distance between adjacent dams when driving the vehicle  10  perpendicular to the rows (from step  102 , ( b ) and ( c )) is divided by cos α, α calculated based upon the row orientation (step  102  ( a )) and the measured heading of vehicle  10  to obtain the required distance from the last dam  82  to the next dam  82 . 
     In step  114  it is determined whether vehicle  10  has already passed the required position. For this step, the distance is taken from one or both of the location signal generation arrangements  32  and  70 . In another embodiment, a radar sensor for measuring ground speed or a tachometer associated with the vehicle  10  can be used, the speed signals of which are integrated to determine if the desired position has been passed. If in step  114  the required distance has not been covered, step  110  is repeated again. 
     It should be noted that steps  112  and  114  are executed a number of times before the next dam  82  is reached. For simplification, it would be sufficient to perform step  112  only once, approximately when the vehicle  10  is approximately in the middle between two dams  82  (this location can be derived from the distance between two dams  82  determined before the last dam  82  was built), in order to compensate for continuously changing steering directions when driving curves and for reducing the computational efforts. However, these steps can be executed as many times as required by the system to achieve the desired results. 
     If in step  114  the required distance has been covered, in some embodiments of the invention, step  116  is executed, showing a message on a display of the operator interface  30  in which the operator is asked whether he or she would like to make a manual adjustment. The operator can then input whether a manual adjustment is intended; if not, step  108  follows. Otherwise the operator can input required corrections into the operator interface  30 , which are then automatically used by controller  26  to position vehicle  10  accordingly, and/or vehicle  10  can be driven forward by the operator until a confirmation input into the operator interface  30  is made, confirming that the latch  66  can now be raised since the tool  54  is in the correct location to leave a new dam  82 . Then, also step  108  follows. 
     In a preferred embodiment, the vehicle  10  is automatically steered along the head ditch  80 , based upon a map stored in memory  28  and signals from one or both of the location signal generation arrangements  32  and  70 . Before the actuator  68  is lifted, the vehicle  10  can be slowed down or stopped to allow the operator to visually check whether the tool  54  is in an appropriate position before actuator  68  is lifted, and to perform manual corrections, when necessary, via operator interface  30  or by controlling the vehicle  10  manually. However, this verification is not required. 
     It would also be possible to input fine adjustment data or correction data into operator interface  30  if the dams  82  would otherwise not be in the appropriate location. This fine adjustment or nudge feature allows the operator to continuously fine tune the system to accommodate historical field errors. 
     The invention is not only suited to build rotobucks as described, but can be used for any agricultural operation at the end of rows that need to be made in defined positions with respect to the location of the rows. 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.