Stability analysis of sampled-data output-feedback polynomial fuzzy-model-based control systems

This paper presents the stability analysis of sampled-data output-feedback polynomial fuzzy-model-based control systems. A sampled-data output-feedback polynomial fuzzy controller is proposed to control the nonlinear plant represented by the polynomial fuzzy model. The proposed sampled-data output-feedback polynomial fuzzy controller makes use of the system output for control. Furthermore, due to the sampling activity, the control signal will be kept constant during the sampling period which complicates the system dynamics and makes the stability analysis difficult. The system stability is investigated based on the Lyapunov stability theory using the sum-of-squares (SOS) approach. SOS-based stability conditions are derived to guarantee the system stability and aid the stable design of the sampled-data output-feedback polynomial fuzzy controller. With the third-party Matlab toolbox SOSTOOLS, the solution to the SOS-based stability conditions can be found numerically. A simulation example is given to demonstrate the merits of the proposed control approach.