Tracking control of sampled-data fuzzy-model-based control systems

The tracking control approach for the sampled-data fuzzy-model-based control systems is presented. Compared with the stabilisation problem, tracking control problem is more difficult as the system states of the nonlinear plant are required to be driven to follow those of the stable reference model. A sampled-data fuzzy controller is proposed to realise the tracking control problem. The sampling activity introduces discontinuity, which complicates the closed-loop system dynamics and makes the system analysis difficult. As a result, the stability analysis approach used in pure-continuous fuzzy control systems cannot be applied. Furthermore, favourable characteristics that lead to relaxed stability analysis results vanish because of the existence of the sampling activity. The system stability is investigated using the Lyapunov-based approach. The membership function information of both fuzzy model and fuzzy controller is employed to alleviate the conservativeness of the stability analysis results. LMI-based stability conditions are derived to aid the design of stable sampled-data fuzzy-model-based tracking control systems. An application example is given to illustrate the merits of the proposed approach.