Disturbance Rejection Stable Fuzzy Controller Design for a Class of Nonlinear Electromechanical systems, in presence of Parametric Uncertainties

Takagi and Sugeno have proposed a fuzzy model for a continuous system in which disturbances are also considered as a time-dependent variable function in the consequent part of the fuzzy model rules. To eliminate the disturbances effect on the output of a system with a Takagi and Sugeno fuzzy model, researchers have proposed a linear matrix inequality-based minimization problem in which system parameters are directly present in the problem constraints. In electromechanical systems, the existence of parametric uncertainties such as uncertainties in the moment of inertia matrices and inaccuracy of actuators parameters cannot be neglected in any way. In this paper, at first, by solving an optimization problem, the upper bound of the uncertainties in the system parameters is determined, and the fuzzy model with disturbances is extracted in the presence of uncertainties. In the following, in order to eliminate disturbances in the presence of parametric uncertainties using a stable fuzzy controller based on the parallel distributed compensation, a minimization theorem based on the new obtained fuzzy model is proposed and its validity is proven. Finally, to evaluate the performance of the proposed controller, a boat-mounted camera stabilizer is used as a case study. The simulations results well demonstrate the favorable efficiency of the proposed controller in eliminating disturbances by taking into account the parametric uncertainties.