Application of fuzzy PID self-adaptive controller in pressurisation control system of counter gravity casting

Abstract

Good counter gravity casting process control is very important to the production of high quality light metal parts. However, due to uncertain dynamic properties, large delay and interactive influencing factors, this kind of process control is quite complex and it is hard to build a precise mathematic model to describe its characteristics. PID control dose not depend on mathematic model, but once the parameters are given, it cannot regulate itself and cannot get satisfied control effect. In order to satisfy the higher control performance requirement, fuzzy logic control is introduced, which is used to revise three coefficients of PID controller. It can greatly overcome the defects of conventional parameter fixed PID algorithm and get a good self-adaptive ability. Compared with the commonly used classical PID controller, the proposed fuzzy PID controller shows excellent robustness against system parameter variations and external disturbances in the counter gravity casting machine.