Applied Research On Giant Magnetostrictive Actuator For Jet-servo Valve

GMM（Giant Magnetostrictive Material）is a new type of intelligent material with giant strain,fast response speed, high energy density, which interests the scholars all over the world. Based on thecharacteristics of GMM and its applications in fluid control, we design a more accurate, suitable forflow control—GMA（Giant Magnetostrictive Actuator）for jet-servo valve. Its overall structure, finiteelement analysis and optimization of electromagnetic properties, active cooling and passive tempera-ture compensation structure, the finite element analysis of temperature field, mathematical modelingand experimental testing are discussed in this paper.On magnetic circuit design of GMA, by contract of permanent magnet and the coil and dual coildriven modes, a proper magnet driven method was determined. On the basis of the magnetic theory,the driven coil and bias coil were designed. Through the finite element simulation software COMSOLMULTIPHYSICS, the nμmerical calculations were computed: the GMM rod magnetic induction was"saddle" distribution; under the same driven currents, when the bias currents increase, the resultingmagnetic inductions were greater, which provides a theoretical basis for designing the bias current;the smaller the GMM rod diameter is and the longer the length is, the more uniform the magnetic in-duction is. A large permeability can improve the size of the magnetic induction; the uniformity of themagnetic flux density changes with the form of the adjusting screw, and so on. The magnetic circuitoptimization was given through different structures, different parameters of finite element calcula-tions.In a comparative analysis of the current domestic and international existing control thermal de-formation of GMA, active cooling and mechanical structure of the temperature compensation methodare designed. Numerical simulation was used to analyze the active cooling, including the cooling ef-fect of water and oil cooling. The results show that the cooling effect of flowing water is better thanthe oil flow cooling effect, which is the phenomenon of thermal convection; the static cooling effectof poor water is worse than static oil cooling effect, which is the thermal conductivity phenomenon.By experimental methods, more than10μm thermal displacement was obtained by temperature com-pensation method; by active cooling and mechanical way of compensation structure, the thermal out-put displacement could be controlled within the3μm in ten hours of continuous work conditions,which reached the temperature control requirements.Meanwhile, in the comprehensive analysis of the electromagnetic optimization of temperature controlling optimization, a sample of GMA is made, built a test system. Its displacement (or force)static and dynamic output characteristics were tested. The experimental results show that the fre-quency response of the GMA was more than600Hz, which provided an experimental basis for thedesign of the GMA.