Piece-wise non-fragile control of PMSM servo systems

For the nonlinear problem of PMSM servo systems approximated by the T-S fuzzy model, the non-fragile controller is designed by the piece-wised method. Firstly, we divide the input space into amount of fuzzy subspaces, and improve the approximation accuracy and control accuracy by constructing a local fuzzy model and controller in every subspace. Then, the global dynamic fuzzy model is constructed by combining these local fuzzy models smoothly. Based on this global dynamic fuzzy model, we can design the global fuzzy controller to control the whole system. The controller is considered to be with additive gain variations. By using the linear matrix inequality (LMI) method, the simulation of the PMSM servo systems is implemented, and the simulation result illustrate the effectiveness of the design method.