Feedforward-plus-proportional-integral-derivative controller for an off-road vehicle electrohydraulic steering system

Abstract

This paper presents the use of a feedforward-plus-proportional-integral-derivative (FPID) controller for improving the control performance of the electrohydraulic steering system on an offroad vehicle. The FPID controller used an inverse valve transform in the feedforward loop to compensate for an electrohydraulic steering system deadband and used a conventional PID feedback loop to minimize the tracking error in steering control. On-simulator evaluation tests verified that the FPID resulted in a superior steering rate tracking performance over both a feedforward controller and a PID controller. On-vehicle evaluation tests verified that this FPID controller could achieve prompt and accurate steering angle tracking for agricultural vehicle automated guidance applications.