Self-steering control system for agricultural machines esp. combine harvester

摘要

The system has the agricultural vehicle equipped with position sensors, to locate items to be harvested, which provide analogue voltage signals to an electronic unit which then controls the direction and speed of the vehicle. The vehicle (1) is automatically steered along the edge or perimeter (GK) of a cereal field (GF) by means of a position-sensing arrangement (OV) directing a beam (OST) along the perimeter. A signal (OS) is transmitted to a control unit (ST) as well as a speed signal (VS) from a front wheel (VR) of the machine. A datum steering condition may be set manually at the control unit. A hydraulic steering control cylinder (LZ) is operated by left and right proportional valves (PVL,PVR) and moves the rear wheels (HR) and a wheel position sensor (RSS) sends a signal (RWS) to the control unit. The steering control valves are sprung to a closed position so that with no control signal steering is by the steering wheel (R). Proportional amplifiers (10,20) convert detected steering error signals to the steering control valves which then correct the direction of travel of the machine at a rate determined by the speed signal (VS).