Disturbance rejection performance of generalized predictive control

Discussion about disturbance rejection properties of generalized predictive control (GPC) is provided in the form of pole-placement and internal model control structure. It is pointed out that the nonzero mean noise signal of the open loop has become a stationary noise signal in a closed loop, and that GPC is robust with respect to steady-state offset in the measured variable from the set point. Based on the closed loop transfer functions of disturbance channels and the frequency properties of GPC, it is demonstrated that the use of an observer polynomial T can give enhanced robustness against high frequency noise and unmodelled dynamics and enabled independent tailoring of set-point and disturbance responses.