In this paper, we examine a design method for low-sensitivity control with robust stability using multiplex feedback control. When the system has low-sensitivity characteristic, the steady state error for the reference input and influence of disturbance for the output become small. But the low-sensitivity control has bad robust stability characteristic, because of sum of the sensitivity function and the complementary function is equal to 1, and then the complementary sensitivity function tend to be 1. Yu et al. propose a design method of low-sensitivity control with robust stability for the plant having uncertain number of unstable poles using two-degree-of-freedom control and double feedback control. In this paper, we expand the result by Yu et al. and propose a design method of low-sensitivity control system with robust stability using multiplex feedback control.
