Tracked vehicle closed loop steering system

A control system for a tracked vehicle drive/steering system having an engine driven hydraulic steering pump which drives a hydraulic steering motor, the steering pump being responsive to steering pump control signals, an operator manipulated steering wheel for generating steering command signals, the steering motor providing an input to a differential track drive mechanism which responds to manipulation of the steering wheel and turns the vehicle and drives left and right tracks, the control system comprising:

• a steering wheel position sensor which generates steering wheel position signals;
• a steering motor position sensor which generates actual steering motor position signals;
• a wheel speed sensor which generates wheel speed signals;
• a motor displacement value generator which generates a motor displacement value as a function of the steering wheel position signal and the wheel speed signals;
• a motor target position value generator which generates a motor target position value as a function of the motor displacement value;
• a motor desired position value generator which generates a motor desired position value as a function of the target position value;
• a motor position error generator which generates a motor position error value as a function of the desired position value and of the actual steering motor position signals;
• and
• a steering pump control signal generator which generates the steering pump control signals as a function of the steering motor position error signals.