An improved approach to fuzzy model construction and servo control with constraints based on error dynamics

This paper presents an improved approach to servo control for nonlinear systems with constraints on inputs and states using the fuzzy model-based control approach. In our previous paper, servo control based on error dynamics using error vector and input difference was proposed. Although the approach can achieve servo control with constraints on both of inputs and states, error dynamics with time-varying extra terms cannot be applied. In this paper, time-varying cancellation input is newly introduced. By using the cancellation input, servo control for error dynamics with time varying extra terms is achieved. We derive servo controller design conditions and constraint conditions on inputs and states in the form of LMI. Design examples illustrate the utility of this approach.