Robust adaptive control design of nonlinear systems with input delay

Abstract In this paper a robust adaptive controller for a class of uncertain nonlinear systems is developed with additive disturbance and unknown time‐varying input delay. The control law is composed of a Desired Compensation Adaptation Law (DCAL) based feedforward term for the adaptation of uncertain plant parameters and two robust feedback terms based on the integral of the past control to compensate the input delay. The sufficient conditions on controller gains and limit on delay bound are derived through stability analysis by choosing suitable Lyapunov‐Krasovskii functionals which gives a globally uniformly ultimately bounded (GUUB) tracking. The performance of the controller is evaluated by performing simulation on a two link robot manipulator system for different values of the input delay.