Application Of The Variable Universe Fuzzy PID Control Of The Compressor

The compressed air in the industrial applications are considered to be second only to the power, and also is the process gas source multiple purposes. Its applications throughout the metallurgical, chemical, tobacco, machinery, medicine, food and other industries. Air compressor system as a compressed air supply system with time-varying and nonlinear characteristics, it is difficult to establish a precise mathematical model. Conventional PID parameter adjustment relies on the experience and knowledge of the on-site staff and related fields experts knowledge. For the complex control object, which with no precise mathematical model, the traditional PID control techniques could not meet the control requirements very well. Fuzzy control has been widely used because of its simple structure, unwanted mathematical model of the controlled object etc. In this paper, the fuzzy mathematical knowledge is applied to control the pressure of the air compressor. In the fuzzy adaptive controller, when the control system output is close to zero, the initial universe fuzzy partition becomes rough and affect the control accuracy of the system, in order to solve the problem, the idea of the variable universe is introduced to the fuzzy adaptive PID control. And change the telescopic range of variable universe by the Fuzzy inference, to reach the goal of variable universe adjusts as the system changes. This paper did research works are as follows:For the air compressor output pressure changes, this paper designed a fuzzy controller which regards the pressure difference and the pressure change rate as input and the compressor motor frequency as output.In this paper, for the same fuzzy rules in the fuzzy adaptive PID control affect the control accuracy, the variable universe fuzzy PID controller is given, through the application of fuzzy reasoning to describe the variation of the variable universe, and Online adjust the input and output universe by retractable factor regulator. Variable universe fuzzy control is an emerging field of research, the experimental results show variable universe fuzzy PID technology is feasible, the method has a certain practicality and replicability, providing a theoretical basis for future air compressor control system design, and also has a certain reference value.