Robust Adaptive Path-Tracking Control of Autonomous Ground Vehicles With Considerations of Steering System Backlash
Xingyu Zhou, Zejiang Wang, Heran Shen, Junmin Wang
Abstract
Backlash phenomena have haunted control engineers for ages. Concerning the ground vehicle path-tracking control system design, the steering system's backlash attribute is often overlooked. If not properly compensated, the backlash nonlinearity tends to provoke unfavorable consequences including erroneous positioning of the road-wheel steering angle, response chattering, limit-cycle-like oscillations, and delays. This paper pioneers to employ an adaptive inverse controller to offset the dynamics of the steering system's backlash. Overall, the path-following objective is accomplished via a novel trio-loop control architecture, which decomposes the tracking objectives into kinematic, vehicular lateral dynamics, and steering backlash compensation sub-levels. All adaptive control laws are robustified by means of sigma modification. Hardware-in-the-loop experimental results are presented to demonstrate the superiorities of the proposed solution.