Towards Enhancing Robustness Of Prescribed Performance Controllers In The Presence Of Control Input Delays

In this paper, we propose a state-feedback controller, designed with the help of the prescribed performance control methodology, to achieve prescribed performance attributes (i.e., maximum overshoot, minimum convergence rate, maximum steady-state error) on the output tracking error, for a class of uncertain nonlinear systems of known high relative degree, and despite the presence of delays in the control input, which are constant and known. Besides being continuous, the proposed solution does not utilize either bounds of the system nonlinearities or high order derivatives of the desired output trajectory. In addition, no hard calculations, analytic or numerical, are required; making its implementation straightforward. Simulation studies clarify and verify the approach.