Soil cultivation implement control apparatus and method

Abstract

A soil cultivating apparatus including a tractor ( 2 ) towing a row cultivator ( 4 ) by means of a three-point linkage ( 6 ). The row cultivator ( 4 ) includes a fixed portion ( 8 ) and a moveable portion ( 10 ) having soil scarifying tools ( 18 a - 18 n ). The movable portion ( 10 ) is laterally moveable relative to the fixed portion ( 8 ) by means of linkages ( 12 a - 12 d ) and is effected by a hydraulic actuator ( 22 ) under control of tool-bar control system ( 20 ) which is able to determine the position of the moveable portion ( 10 ) relative to the fixed portion ( 8 ) by means of a sensor ( 24 ). Mounted upon the moveable portion ( 10 ) is a DGPS antenna ( 26 ) GPS receiver that forms part of the control system ( 20 ). The control system ( 20 ) has a microprocessor which operatively executes a stored program. The microprocessor receives data from an intra-rig sensor and from the GPS receiver specifying the absolute coordinate of the movable portion ( 10 ) relative to the earth. On the basis of the data received and in accordance with the instructions in the program, the microprocessor generates a series of lateral motion commands which controls the hydraulic actuator ( 22 ). An operator of the system may enter coordinates defining a desired line of travel of the movable portion ( 10 ) by means of a data entry device. Command prompts and other feedback to the operator are displayed by means of a screen.

The claims defining the invention are as follows:  
     
         1 . Soil cultivation apparatus including: 
 a fixed portion associated with propulsion means and guidable substantially along a selected cultivation path;    a cultivator portion linked to said fixed portion;    an actuator operable between said fixed portion and said cultivator portion for effecting lateral displacement therebetween;    a position detector located on said cultivator portion and establishing position data for said cultivator portion;    a relative lateral position sensor generating relative position data corresponding to the lateral displacement between said fixed portion and said cultivator portion; and    a processor accessing way line data corresponding to said selected cultivation path and operating according to an algorithm selected from a second order PID control loop algorithm and a bang-bang algorithm selected to use said position data and said relative position data to generate a control signal operating said actuator to effect corrected tracking of the cultivator portion substantially along said way line.    
     
     
         2 . Soil cultivation apparatus according to  claim 1  wherein the position detector is a Differential GPS positioning system including Differential GPS base station a GPS receiver and an antenna.  
     
     
         3 . Soil cultivation apparatus according to  claim 2 , wherein the relative position sensor includes a rotary transducer.  
     
     
         4 . Soil cultivation apparatus according to  claim 2  wherein the relative position sensor includes a second GPS system including a second antenna located at a point stationary with respect to the fixed portion.  
     
     
         5 . Soil cultivation apparatus according to  claim 4 , wherein the second antenna is mounted on the fixed portion.  
     
     
         6 . Soil cultivation apparatus according to any one of  claims 1  to  5 , wherein said algorithm Includes a second order closed loop PID algorithm to generate the control signal.  
     
     
         7 . Soil cultivation apparatus according to any one of  claims 1  to  6  wherein the desired path of travel Is entered by an operator of the agricultural vehicle and stored in a data storage device accessible to the processor.  
     
     
         8 . A method for controlling a soil cultivation implement of the type Including a fixed portion for the towing behind an agricultural vehicle and a moveable portion laterally offsettable from the fixed portion, the method Including the steps of: 
 towing the implement behind an agricultural vehicle;    monitoring the global position of the moveable portion;    comparing said global position to a predetermined globally specified desired path; and    offsetting the moveable portion relative to the fixed portion in order that the moveable portion tracks the desired path by generating a control signal for controlling an actuator located to effect motion of the moveable portion relative to the fixed portion, said control signal being generated by means of an algorithm selected from a second order PID control loop algorithm and a bang-bang algorithm responsive to said monitored global position and relative position data corresponding to said offset.