Control of uncertain input-delay systems by using input/output linearization with a two-degree-of-freedom scheme

This paper presents a new control scheme for an uncertain nonlinear system with input delay. A two-degree-of-freedom control structure with a time-delay compensator is applied to controller synthesis for handling setpoint tracking and disturbance rejection independently. An input/output linearizing controller based on a disturbance-free model is used to provide tracking ability while a high-gain controller is used to compensate a mismatch between actual outputs and disturbance-free outputs. Performance of the proposed method is illustrated through numerical simulations of time-delay processes with unmeasured input disturbances and random noise parametric uncertainties. The simulation results showed that both unmeasured disturbance and parametric uncertainty can be effectively compensated by the proposed design.