An Automatic Cutterbar Height Controller for Grain Harvesting Machines

A system is described to provide automatic control of the cutterbar height on grain harvesting machines. The system used an ultrasonic sensor to measure distance to the ground surface and a microprocessor to process sensor data and control solenoid hydraulic valves. Field tests of the sensor and control system vere satisfactory, although problems with control stability and false signals from green vegetation were encountered.