An adaptive output feedback control for time-delay systems with input disturbance

Time-delay and input disturbance frequently occur in control systems, which decrease the pre-defined performance of the closed-loop system. This paper presents an output feedback controller that compensates the performance degradation owing to time-delay and input disturbance. Simple adaptive control (SAC) and a new disturbance observer (DOB) approaches have been combined to achieve the control purpose. It is shown that the closed-loop system can be made robust against uncertain time-delay by using the SAC algorithm. For disturbance attenuation a new DOB structure has been used for the non-minimum phase system caused by to the Pade approximation of time-delay. Simulation results show the performance improvement by the proposed controller for reducing the both effects of time-delay and input disturbance.