Multi-loop Model Reference PID Control

Multi-loop model reference control to improve disturbance rejection control performance

Multi-loop control structures can enhance inherent disturbance rejection capacity of classical closed loop control loops: While the classical closed loop PID control loop (inner loop) deals with stability and set-point control, the additional model reference control loop of MIT rule (outer loop) can improve the disturbance rejection control performance without degrading the optimal set-point control performance. Such adaptive disturbance rejection, which is not influencing the set-point control performance, can be achieved by selecting reference models as transfer functions of PID control loops (with ignorable time delay)