A two parameter robust repetitive control design using structured singular values

A two parameter robust repetitive control (TPRRC) is proposed in this paper to achieve robust performance over specified frequency range while perfectly tracking and rejecting periodic signals. A framework is also presented in this paper, in which a low order TPRRC can be designed by substituting the big delay term which causes the high order of designed controller with a fictitious uncertainty. The conservatism of this method is small since the supremum of μ values of the new structure is a very tight upper bound of the original structure. By adding another design freedom, the TPRRC can achieve much more aggressive robust performance than one parameter robust repetitive controller (OPRRC). This synthesis procedure has been applied to a hydraulic servo control problem. The simulation results are presented to illustrate the effectiveness of TPRRC