State-Space Approach to LQG Multivariable Predictive and Feedforward Optimal Control

Two extensions of the LQG optimal control problem are presented which enable prediction and feedforward action to be introduced in a state equation framework. Predictive control is first considered using a discrete-time state-space system model. Future reference values are assumed to be known p-steps ahead and the controller has a two-degrees of freedom structure. The mechanism for introducing feedforward control and hence providing a third degree of freedom is also considered. Both prediction and feedforward action are simple to design and implement using the proposed state-space approach