Stability analysis and development of a class of fuzzy control systems

The paper presents a development method for fuzzy controllers, derived from a stability analysis method based on a linearized model of the controlled plant. The stability conditions are expressed by a set of indices that verify the character of the equilibrium point and its uniqueness, and also measure the relative degree of stability. The proposed development method is applicable to the control of a class of nonlinear plants of arbitrary order, with the right-hand term of the state equation restricted to being a continuous and partially differentiable function. For the sake of simplicity, the presentation is mainly dedicated to second-order systems. The application examples presented here deal with the control of two real-world processes, namely the development of fuzzy control systems intended for the position control of an electro-hydraulic servosystem, and for the speed control of an electrical driving system with a variable moment of inertia. (C) 2000 Elsevier Science Ltd. All rights reserved.