Robustness design of nonlinear dynamic systems via fuzzy linear control

This study introduces a fuzzy linear control design method for nonlinear sy stems with optimal H-infinity robustness performance. First, the Takagi and Sugeno fuzzy linear model is employed to approximate a nonlinear system. N ext, based on the fuzzy linear model, a fuzzy controller is developed to st abilize the nonlinear system, and at the same time the effect of external d isturbance on control performance is attenuated to a minimum level. Thus ba sed on the fuzzy linear model, H-infinity performance design can be achieve d in nonlinear control systems. In the proposed fuzzy linear control method , the fuzzy linear model pro,ides rough control to approximate the nonlinea r control system, while the H-infinity scheme provides precise control to a chieve the optimal robustness performance. Linear matrix inequality (LMI) t echniques are employed to solve this robust fuzzy control problem, In the c ase that state variables are unavailable, a fuzzy observer-based H-infinity control is also proposed to achieve a robust optimization design for nonli near systems. A simulation example is given to illustrate the performance o f the proposed design method.