Event‐triggered adaptive control of strict‐feedback nonlinear systems under output constraints and unknown control direction

Abstract This article is concerned with the tracking control problem for a class of uncertain nonlinear systems under output constraints and unknown control direction. To address the unknown control direction and uncertain system parameters, the adaptive compensation mechanism and Nussbaum gain based control technique are employed. In addition, to reduce the communication burden and computing cost, the event‐triggered control mechanism is introduced into the proposed control scheme, in which both the controller and the parameter estimator are event‐triggered, distinguishing itself from the traditional control method based on event‐triggered mechanism. Two different adaptive event‐triggered control schemes based on the fixed threshold strategy and relative threshold strategy are provided, under both of which, the boundness of all signals in the closed‐loop system are guaranteed and the output of system remains in the constraints. More importantly, the Zeno behavior can be avoided under both the two proposed event‐triggered control schemes. The effectiveness of the proposed event‐triggered control schemes are confirmed by the numerical simulation.