Control of the process with inverse response and dead-time based on disturbance observer

A modified disturbance observer based control scheme is proposed to control the processes with inverse response and dead-time. The two parts of proposed control scheme have explicit physical meanings: prefilter acts as a predictor of future control signal, and disturbance observer is used to reject the disturbance. It is a two degree-of-freedom control scheme. Two adjustable parameters are directly related to the performance of set-point response and disturbance rejection. Two disturbance observer design methods are proposed to reject step and ramp disturbances. Robustness of the closed-loop system is discussed. The proposed method is implemented on control software and applied on the dual-process simulator. Simulation and experimental results demonstrate the effectiveness of proposed method.