Research On The Control Technology Of Giant Magnetostrictive Actuator For Servo Valve

In recent years, many scholars at home and abroad have researched on new functional materials inthe application of electro-hydraulic servo valve, especially on GMM (Giant Magnetostrictive Material)based electric-mechanical converter research and development, thus new means to improve thefrequency and accuracy of electro-hydraulic servo valve were supplied.However,at this stage,becauseof the GMM internal complex nonlinearity and hysteresis characteristics, the output displacement ofgiant magnetostrictive material and its devices possess strong hysteresis，serious nonlinear,and lowpositioning accuracy,which is some of the key technical problems need a breakthrough in practicalapplication. In this paper, based on Giant Magnetostrictive electric converter (Giant MagnetostrictiveActuator, referred to as the GMA) in the application of electro-hydraulic servo as the background, thehysteresis nonlinear modeling of GMA and its control technology study are discussed.On hysteresis nonlinear modeling of GMA, by described the composition and working principle ofGMA in detail,the models of GMA,aimed at GMA’s static and dynamic hysteresis,have been foundedaccording to Preisach and Prandtl-Ishlinskii hysteresis theory.The Preisach static hysteresis modelbetter describe the GMA’s hysteresis situation under quasi static input signal,in order to expand theapplication of Preisach hysteresis model, a novel tangent function hysteresis operator isproposed,whose shape parameters is related to the input rate, so the shape of the new operator isvariable.Then a dynamic Preisach model is built based on the new operator,and identified by the neuralnetwork.The experimental results showed that the maximum predicted displacement mean square errorand maximum absolute displacement error of the dynamic Preisach model are1.62μm and3.87μmunder the input current frequency range in10~100hz.Considering the GMA control system researchneeds, Preisach model distribution function is difficult to obtain and its inverse model need designmore complex algorithm to realize,Prandtl-Ishlinskii hysteresis model is established based on thePreisach model.The experiment studies have shown that the Prandtl-Ishlinskii hysteresis model of theGMA flexibility to describe the GMM devices hysteresis behavior, and facilitate the realization of thecontroller design and real-time applications;On control technology study of GMA,the controller system of GMA based on TMS320F2812DSP,including the A/D module,D/A module, serial interface module,servo amplifier module ect. At the sametime, the development of corresponding software of the control system is completed in the integrateddevelopment environment CCS3.3.The prototype of controller system of GMA based onTMS320F2812DSP was developed, the experiment result has proofed that the controller system of GMA can effectively compensate the input signal frequency in the range of0~50Hz GMA hysteresisnonlinear.