Study On A Novel Three-Dimensional Fuzzy Controller And Its Application

Since N.Wiener published 'Control Theory' in 1940's, with the rapid development of science and technology, modern control theory has developed based on the classical control theory, but the conventional control theory that is based on precise mathematical model is challenged by modern control system because it is of complexity, its measurement and system dynamics character is of no precision, and more and more excellent controllers are needed. Intelligent control appears and is developed in the conditions. The intelligent control is a new field of discipline and an advanced control theory. It is mostly used to solve the complex control problems which are difficult to solve in conventional method. Fuzzy control is a main branch of intelligent control. Fuzzy control has developed for twenty years and many achievements have been reached in both in research and in practical applications. It will be one of important technologies in research and application in the future. Based on research results of fuzzy controllers, this paper present a new three-dimensional fuzzy controller. Its design method was discussed based on theory and practical applications, and its results of simulation to some models and pumps used in chemical engineering were given.Main work of this paper is as follows:â… . To introduce formation, present, and developing trends of fuzzy control theory.â…¡. To introduce fundamental principle and designing way of conventional two- dimensional fuzzy controller.â…¢. To introduce merit of conventional two-dimension Fuzzy controller, at same time, analyze the fatal shortcomings of it in detail, and introduce concept of three-dimensional fuzzy controller.â…£. To analyze the principle of conventional three-dimension fuzzy controller, and fund that three-dimension fuzzy controller is still imperfect.â…¤. To put forward two methods of analyzing stability of fuzzy control according to model of three-dimensional fuzzy controller present by the paper, and discuss the stability and stable design way of this new three-dimensional fuzzy controller. â…¥. To show that the new three-dimensional controller could approximate any nonlinear functions to an accuracy degree by researching on the approximation of the three-dimensional fuzzy controller.â…¦. To simulate of some linear mathematical models and nonlinear mathematical models using MATALB. Very good results were obtained.â…§. To combine the three-dimensional controller with frequency conversion control of electromotor, and apply it to control of a process pump. Good simulation results were shown. From the above work, the conclusions were obtained as follows.â… . By comparing novel three-dimensional fuzzy controller with two-dimensional fuzzy controller, the former is better than the latter in control speed and stability and obviously improves quality of control.II. By comparing proposed novel three-dimensional fuzzy controller with conventional three-dimensional fuzzy controller, the former could meet the requirement of on-line adjustment.â…¢. The proposed novel three-dimensional fuzzy controller is successfully used in a control system of a process pump.Fuzzy control technology has found many uses in fields of economy and nation defense. With continuous development of fuzzy control theory and improvement of control algorithm, performance of fuzzy controller to control pump will be getting better and better, and fuzzy control technology will be further improved.