Practical Tracking Control via Switching for Uncertain Nonlinear Systems With Both Dead-Zone Input and Output Constraint

This brief concerns practical tracking for a class of uncertain nonlinear systems with both time-varying dead-zone input and output constraint. Compared with the closely related literature, two essential obstacles exist which lead to the incapability of the traditional schemes: first, both the output constraint functions and the reference signal are only first-order continuously differentiable without any their time derivatives to be available for feedback. Second, the system possesses essential nonlinearities and serious uncertainties which are reflected in that the unknown nonlinear terms are dominated by an unknown constant multiplying a smooth function while the control coefficients are unknown without known bounds. To effectively solve the control problem, a novel switching control framework is developed in this brief. Consequently, a switching controller is designed with some pivotal controller parameters being tuned by a smart switching mechanism, which guarantees that all the states of the resulting closed-loop system are bounded while system output practically tracks the reference signal without the output constraint being violated. Finally, the theoretical results are validated by simulation.