Realization of nonlinear and linear PID controls using simplified indirect fuzzy inference method

In this paper, we propose a more practical method for realizing nonlinear and linear PID controls using fuzzy inference methods than previous ones. This proposed method is based on the fact that not only nonlinear but also linear PID control can be easily realized by applying the simplified indirect fuzzy inference method for fuzzy control to few fuzzy control rules with a simple structure. Therefore, we first show that nonlinear PID control, which is based on a conventional PID controller, can be realized using this proposed method. Secondly, we show that linear PID control can also be realized simply by replacing the arctan with the linear membership function in the antecedent part of the fuzzy control rules. (C) 1999 Elsevier Science B.V. All rights reserved.