Output tracking for nonlinear discrete-time systems via fuzzy control approach

The output tracking control problem is investigated for a class of nonlinear discrete-time systems via Takagi-Sugeno (T-S) fuzzy observer-based control approach. A delayed fuzzy observer is firstly established to estimate state variables and premise variables. Then, a target state is built to convert the output tracking problem into the stabilization problem of a tracking error system. As a result, we can use the approaches for stabilization problems to realize the output tracking. Finally, a new delayed nonquadratic Lyapunov function is introduced to design controller gains and observer gains separately. Two practical examples, subsuming PWM buck converter and mass-spring-damper system, are considered to show the effectiveness of our results. A numerical example demonstrates the superiority of the proposed method.