Abstract:Traditional Smith-Predictor fails to provide a null steady-state error in the presence of a constant load disturbance if the process exhibits an integral dynamics(IPDT), and under compensation when the model mismatches. The modified Smith-Predictor is proposed for it. Firstly, the feedback controller can transmit the error which comes from the difference between actual process and the model process to the control signal. Secondly, series controller and Feedback recourse controller are added to the input of plant, and the controllers are using different methods to design. MATLAB simulation shows that the system has better output response, and also eliminates the steady-state error.