A model predictive controller for multirate cascade systems

Cascade control strategy is commonly employed in process control. Usually, the inner loop is run at a higher sampling rate than the outer loop to achieve an effective cascade control. We present a model predictive controller (MPC) that could handle this multirate cascade control strategy in a straightforward manner. There is only one controller to be designed, thus reducing the complexity of tuning the cascade control system. An illustrative example is presented to demonstrate the effectiveness of the proposed control design method.