Hysteresis control of nonlinear single-acting actuators as applied to brake/throttle switching

This paper expands upon some of the design techniques of Gerdes and Hedrick (1999) in order to analyze a class of switched nonlinear systems with hysteresis. Physically, this class represents systems in which the input is supplied by two single-acting actuators (one capable of "pushing", the other of "pulling"), each possessing first-order nonlinear dynamics. The basic control structure proposed involves multiple sliding surface control together with a hysteresis element designed to reduce chattering problems. The physical motivation for such a system comes from the problem of coordinating throttle and brake actuation in vehicle longitudinal control. This paper describes a choice of controller gains which guarantee a desired level of performance in the presence of model uncertainty, the hysteresis element and the rate limit saturation exhibited by single-acting actuators upon release. The paper concludes with experimental verification that the hysteresis controller eliminates chatter without degrading tracking performance.