Robust controller design for uncertain multiple-delay systems with unknown actuator parameters

This paper considers the controller design problem for a class of uncertain systems with unknown actuator parameters. The considered systems are with multiple time delays and nonlinear uncertainties, and the uncertain nonlinearities are bounded by nonlinear functions with unknown coefficients. The actuator parameters are time-varying and their bounds are unknown, moreover the signs of them are not available. To deal with unknown actuator parameters problem, we decompose the system into two subsystems. For the resultant system, we develop the corresponding tolerant controller design method with the help of Nussbaum function. By constructing the Lyapunov Krasovskii functional, we prove the asymptotical stability of the closed-loop system. Finally, simulations are performed on a chemical reactor system to show the effectiveness of the proposed method.