Optimal preview repetitive control for impulse-free continuous-time descriptor systems

This paper concerns the design problem of optimal preview repetitive control (OPRC) for impulse-free continuous-time descriptor systems. First, by using a linear transformation, the descriptor system is transformed into a normal system with relatively low dimensionality and an algebraic system. Based on this, an augmented system which contains the error vector and the derivative of the normal system is constructed. Then, applying the lift technique and introducing a new performance index, the OPRC designing problem is converted into a regulation problem. Based on the optimal control theory, the regulator problem of the augmented system is solved. Furthermore, the explicit OPRC law for the original system is deduced. Different from the existing results, the preview feed-forward and error integral compensations are added into the OPRC system, which can significantly improve the tracking performance. Finally, a numerical example simulation result verifies the validity of the proposed method.