Study on low-sensitivity control system with robust stability for minimum-phase and multivariable systems using multiplex-feedback control system

Abstract

In this paper, we examine a design method for low-sensitivity control with robust stability for multiple-input/multiple-output continuous time-invariant systems and minimum-phase systems using two-degree-of-freedom control system and multiplex feedback control. On Low-sensitivity control system the steady state error for the reference input and influence of the disturbance for the output became small. But the robust stability on low-sensitivity control became bad because the sum of the sensitive function and the complementary sensitivity function is equal to 1, the low-sensitivity and robust stability on the control system respectively depend on the sensitivity function and the complementary sensitive function. However According to Yamada, Low-sensitivity control system make the system robust stable with considering the class of uncertainty. And according to Yu et al. and Koyama et al. Using stratifled two-degree-of-freedom control, we can design more low-sensitivity characteristics than that of single two-degree-of-freedom control. In this paper, we expand the results of Yamada, Yu et al. and Koyama et al. and propose a design method of more low-sensitivity control system for multiple-input/multiple-output systems using two-degree-of-freedom control and multiplex feedback control system.