Asymptotic adaptive tracking with input amplitude and rate constraints and bounded disturbances

Abstract

In this paper, we develop a direct model reference adaptive control framework for asymptotic adaptive tracking in the presence of actuator input amplitude and rate constraints for some classes of uncertain linear time-invariant systems and nonlinear systems. This framework also allows for rejection of bounded time-varying disturbances, without causing any chatter in the control input. Moreover, positive (ρ; μ)-modification is proposed to protect the control law from the actuator saturation limits. The design is model-based and ensures global asymptotic tracking for open-loop input-to-state stable systems, while an estimate of the domain of attraction is derived for local asymptotic tracking in the case of input-to-state unstable systems. The approach is illustrated with examples.