A modified smith predictor for a process with an integrator and long dead-time

In this paper, a new modified Smith predictor using a rapid load estimator scheme is proposed. The advantage of the design is that the load estimator does not involve the solution of a closed-loop equation that contains dead time, and this can achieve a better load disturbance response. This scheme can be easily extended to the case of double integrators. Robust stability of the proposed method is analyzed, and a simple and effective robust controller design rule is derived. It is demonstrated by simulations that the new controller provides a similar or better setpoint response and a faster load disturbance rejection than the dead-time compensator in other papers.