Research On Modeling Of Valve Controlled Asymmetric Cylinder Hydraulic Servo System Based On Fuzzy Identification

Electro-hydraulic servo control system is widely used in the fields of robotics and defense industry because of its advantages of large power density and high control precision.Accurate mathematical model is an important prerequisite for achieving high quality hydraulic servo control.However,due to the complex control mechanism of hydraulic servo system and the large number of parameters and structural uncertainties,it is difficult to obtain the accurate mathematical model only through mechanism analysis.In order to solve this problem,the mathematical model of hydraulic servo system of valve-controlled asymmetrical cylinder is established by fuzzy identification.Fuzzy identification is an advanced data-based modeling method,which can obtain accurate mathematical model only through input and output data of the system.It is widely used in power grid system,food industry and other fields.In this paper,the input and output data of the hydraulic servo system of valve controlled asymmetrical cylinder are obtained through the experiment.Based on the fuzzy identification,the accurate model of the hydraulic servo system is established,which provides the basis for the system analysis and control design,and aims to improve the control accuracy and robustness of the hydraulic servo system of valve controlled asymmetrical cylinder.In this paper,the modeling method of hydraulic servo system based on fuzzy identification is deeply analyzed and studied.The specific research work is as follows:Firstly,in the structural identification of takagi-sugeno fuzzy model,the clustering effect of fuzzy c-means clustering algorithm and Gustafson-kessel clustering algorithm was analyzed and compared from qualitative and quantitative aspects,and the advantages of Gustafson-kessel clustering algorithm were verified by simulation examples.The optimal cluster center number is selected by cluster validity measurement function and compatible cluster merging algorithm.The simulation results show that the fuzzy model based on the identification of the optimal cluster center number has higher identification accuracy and better model quality.Then,in the Takagi Sugeno fuzzy model parameter identification,analysis and comparison the total least squares algorithm,local weighted least squares algorithm and the characteristics of the global least square algorithm,simulation results show that the fuzzy model based on global least squares identification algorithm has higher identification accuracy,demonstrate the superiority of the global least square algorithm.Finally,the input and output data of the valve-controlled asymmetrical cylinder hydraulic servo system are collected.Based on the experimental data set and the modeling and optimization method of takagi-sugeno fuzzy model,the mathematical model of valve-controlled asymmetrical cylinder hydraulic servo system with high identification accuracy is established,which provides the basis for system analysis and control design.The comparison between the identification model and the measured data shows the superiority and effectiveness of fuzzy identification in the field of electro-hydraulic servo system identification.