Fuzzy model-based servo control with constraints on both of inputs and states

This paper presents servo control for nonlinear systems with constraints on both of inputs and states using the fuzzy model-based control approach. In our previous paper, we proposed servo control with input constraint by introducing input difference between present input and final input. However, it is difficult to constrain both of state of the nonlinear systems and the control input at the same time since time-derivatives of state are used. In this paper, we construct the nonlinear error system based on error vector between state and the target point for servo control. By employing the error system representation and the input difference, servo control with constraints on both of inputs and states can be achieved. We derive LMI conditions for designing servo controller and for constraining control inputs and states. Servo controller with constraints is designed by simultaneously solving servo controller design condition and the constraint conditions. A design example illustrates the utility of this approach.