State space region with guaranteed L{sub}2/L{sub}∞ performance for saturating control systems - an analysis method focusing on L{sub}∞ input signals

摘要

This paper proposes analysis method of state space region with guaranteed L{sub}2/L{sub}∞ performance for control systems having direct-feedthrough matrix from both disturbance input and saturating output to saturating input. We define the region and characterize it based on the circle criterion. It is the key idea of our analysis method using the circle criterion to derive a new constraint of magnitude bound on the saturating input by considering the fact that both the disturbance input and the saturating output are L{sub}∞ bounded signals. Our result can reduce conservatism of the existing circle approach which deals with the direct-feedthrough matrix using a global sector bound on the saturation nonlinearity.