Research on fuzzy symmetrical control of valve controlled asymmetric hydraulic cylinder system

Abstract

In order to solve the problems, such as the asymmetry, complex control methods, inconsistent dynamic characteristics for positive/negative directions and poor stability for asymmetric control system, in this paper, a system symmetric control method based on state feedback was brought out and the state space mathematical model was derived for valve controlled hydraulic cylinder system. With the symmetric control method of the state feedback, the valve controlled asymmetric hydraulic system can be converted into state space symmetric system, then the unified control method can be used for positive and negative directions after conversion, finally the feedback link of the system was educed. Through simulation, the accuracy of the model and the effectiveness of the control method were verified. Through experiments, the input and output characteristics and load response characteristics of the system before and after conversion were compared. It was concluded that the system had symmetric characteristics for inputs and outputs, and better load response characteristics after conversion. This study can be a base for the application of symmetric control theory to large asymmetric hydraulic systems and was of great help to realize symmetric control of large asymmetric hydraulic systems.