Parameter Identification Of Electro-hydraulic Control System Based On Levenbreg-Marquardt Algorithm

Accurate dynamics model of the controlled system is established based control algorithm design,tuning parameters,is the premise and key performance of control system,usually we can through the prior knowledge of the dynamic model of the structure,for the electro-hydraulic control system,but because of its complex structure,nonlinear and time-varying characteristics,on the basis of the system pressure and flow limited design parameters,through a large number of simplified theory derived the system model parameters and actual parameters of the error,In particular,in the process of work,the external interference signal,such as frequency interference,interference of Nonlinear Grid factors coupling,making it harder for the real control system parameter identification,lead to low control precision,system can not meet the control demand.In view of the above problem,this thesis first analyzes the experiment system of the electro-hydraulic control system under the influence of the external environment disturbance to the system identification,analyze the forming mechanism of noise interference,this thesis expounds the current can be used to reduce the external interference measures of hardware and software measures,analyses the frequency converter and mechanism of electromagnetic interference suppression measures.Then,Put forward a kind of for the electro-hydraulic control system contains noise when the effective identification method of model: L-M(Levenbreg-Marquardt)algorithm,L-M algorithm on system parameters are analyzed,the identification principle of electro-hydraulic control system of controlled object is established mathematical model,and introduces interference,to establish the identification algorithm procedures,L-M algorithm is analyzed by simulink modeling simulation to contain outside noise interference effect of the parameter identification of the electro-hydraulic control system.Compared with the least squares algorithm which is current widely used to parameter identification,simulation results show that the algorithm of L-M parameter identification average error is 6.05%,the error precision up to 9.61%.The least squares algorithm parameter identification average error is 11.48%,the error precision up to 13.09%.The identification speed is faster than the least square method,46.4%,and the recognition effect is better,and the accuracy and speed of the identification of electro-hydraulic control system are improved.Finally,the experimental platform of electro-hydraulic control system was set up,and the identification validity of L-M recognition algorithm was verified experimentally.The results showed that: L-M algorithm to identify system parameter resembles the real input and output characteristics of the control system,identification results can accurately describe the control system model and the characterization of system dynamic characteristics.