Adaptive Control of Input Delayed Uncertain Nonlinear Systems With Time-Varying Output Constraints

Abstract

This paper focuses on the tracking control of a class of uncertain nonlinear systems with consideration of both time-varying input delay and output constraints. By introducing an auxiliary signal, which is based on the finite integral of the past control values in the design procedure, an adaptive controller is proposed to compensate for the effect of input delay and to handle various uncertainties. Meanwhile, an asymmetric time-varying barrier Lyapunov function is employed in the controller design to ensure the output constraint satisfaction. The stability analysis utilizing Lyapunov-Krasovskii functionals reveals that the proposed adaptive controller guarantees a uniformly ultimately bounded tracking performance and the time-varying output constraints are never violated. Two simulation examples are given to verify the effectiveness of the proposed control scheme.

Keywords

• Adaptive control
• input delay
• barrier function
• output constraints
• Lyapunov-Krasovskii functional
• uncertainty