On Steady–State Error–Free Regulation of Right–Invertible LTI MIMO Plants

This paper presents an approach to elimination or reduction of steady-state output errors in regulatory control of continuous-time LTI MIMO systems with a number of inputs not less than a number of outputs. Classical modal and LQR/LQG feedback controllers are effectively supplemented with a feedforward path from a reference vector to a plant's input vector. Conditions for full elimination of the steady-state error are given and the ability for only reduction of the error is discussed. Various simulation examples illustrate the usefulness of the methodology.