Continuous-time linear-quadratic regulator with output feedback

Two state space models are proposed for direct implementation of linear-quadratic regulator with measured not all the state components but only the output of the plant. Using this approach the closed-loop (CL) system with dynamic output feedback regulator (DOFR) is designed. A theorem is proved relating the solutions obtained from the two models. It is shown that, resulting from the second model, the CL systems with the state feedback and with DOFR have the same dynamics and strong robustness property. It is also shown that, by means of appropriate choice of the state weighting matrix in the performance index of the second model, it is possible to obtain a partial pole placement. The internal model of disturbances included to the augmented plant during the design and to the regulator during control implementation, improves the quality of the control