Nonlinear Control of Full-Vehicle Active Suspensions with Backstepping Design Scheme

Abstract

This paper proposes a nonlinear backstepping control strategy to improve the inherent tradeoff between ride comfort of passengers and suspension travel. Passenger comfort in ground vehicles usually depends on a combination of vertical motion (heave) and angular motion (pitch and roll). Suspension travel means the space variation between vehicle body and tires. Our active suspension design has the ability to cope with these two conflicting objectives for improving the tradeoff between them. The novelty is in use of the nonlinear filter whose effective bandwidth depends on the magnitudes of suspension travel. Hence, the nonlinear design allows the closed-loop system to behave differently in various operating regions. As a result, the excellent performance of full-vehicle active suspension is demonstrated in simulations compared to a standard passive suspension system.