Research Of Electro-hydraulic Force Servo Control System

Because of the characteristic of small volume, agile and strong anti-interferenceability,Electro-hydraulic servo control system also has been used in occasion withhigher demand of precision and speed of response now. The characters that nonlinearityand parameter uncertainty of Electro-hydraulic servo system itself, lead to thetraditional PID control algorithm is hard to make the force servo system achievesatisfactory control effect.First,the mathematic model of the system was built under the condition of an idealassumption, and the simulation analysis was taken in Matlab/Simulink software. Thistopic based on the electro-hydraulic servo valve、the resistance strain type forcetransducer and data acquisition card of NI corporation, and other hardwarefacilities,then designed the electric hydraulic servo control system.In view of the above contradiction， the experimental research of the PIDdifferential feedback control、PID feedforward control、Fuzzy PID control and nonlinearPID control algorithm of integral separation was carried separately, according to thecontrol requirements of the system and characteristics of the servo valve, based on theLabVIEW2010software platform in this paper, and compared with conventional PIDand fuzzy control algorithms. The results show that the PID differential feedbackcontrol and PID feedforward controller can improve the overshoot and precision of thesystem, but can’t meet the requirements；the fuzzy PID control algorithm not onlyreserved the characteristic of high steady-state control precision of the conventionalPID control algorithm, also inherited the advantage of robustness of fuzzy controlalgorithm, however, as a result of its system performance is proportional to complexity,it also has certain difficulty even the control performance is superior than conventionalcontrol algorithm. The PID controller of integral separation can make the system response speed quick and overshoot disappear, and the PID algorithm of integralseparation eliminate the deviation and does not produce integral saturation, theresponse time could reach2seconds, and average control accuracy up to99%.