Disturbance observer-based control for processes with an integrator and long dead-time

This paper reveals the disturbance observer-based control scheme, a version of 2-DOF internal model control, for processes with an integrator and long dead-time. The controller can be designed to reject ramp disturbance as well as step disturbances, even arbitrary disturbances. If the model is available, then only two parameters are left to be tuned. One is the time constant of the setpoint response and the other is the time constant of the disturbance response which is tuned to compromise disturbance response with robustness. It has simple, clear, easy-to-design, easy-to-implement structure and good performance. The proposed solution is compared to the best results recently published with some simulation examples