Output-Tracking-Error-Constrained Robust Positioning Control for a Nonsmooth Nonlinear Dynamic System

An output-tracking-error-constrained dynamic surface control (DSC) is proposed for the robust output positioning of a multiple-input-multiple-output nonlinear dynamic system in the presence of both friction and deadzone nonsmooth nonlinearities. An error transformation method and simple barrier Lyapunov function are also proposed to ensure the prescribed output tracking performance and stability without requiring specific observations of the friction and deadzone parameters. In addition, a new adaptive cerebellar model articulation controller-echo state neural networks system is proposed to deal with an unknown nonlinear function to improve the positioning performance. The boundedness of the overall closed-loop signals and the prescribed performance constraints were guaranteed, and precise positioning performance was also ensured regardless of the effects of friction and deadzone. The proposed control scheme was evaluated by simulation and experiment.