Theoretical Fundamental Study Of GMM Actuator For Servo Valves

The Giant Magnetostrictive Material(shorted form:GMM),which came forth in the 70th of last century, is a new type of functional material. It has the following merits:giant strain, fast response speed,high energy density and large output force and so on. In view of its excellent performance and promising foreground in applications, the research on GMM has became the focus of attention all over the world at a time. Also its corresponding theory and applications studies are being researched. Because the GMA made of this material can improve the accuracy and bandwidth of the servo valve, so many researchers of the world countries now have taken part in studying it.Based on the characteristics of the GMM and that produced in our country, the article tends to study the Giant Magnetostrictive Actuator(GMA) for servo valves. The article first presents systematically the working characteristics of the GMM, the research status of abroad and home, the function and the principle of actuator,and the project significance and main contents of the research are provided. Then mainly analyze and study its mechanical structure, electromagnetic circuit and field of GMA for servo valves, such as petermination of driving pole, design of pre-stress device, design and optimization on geometric parameters of coil, analysis of magnetic circuit loss, design and emulation on the output model of GMA, symmetrical analysis of driving magnetic field, finite element analysis and emulation on electromagnetic field of GMA, and so on.Of structure design, the principle of the closed electromagnetic circuit around the GMA is taken into account, so magnetic leaking is greatlyl reduced and magnetic intensity around GMM improved as well. On coil design aspect, optimization design method is put into use to keep higher electromagnetic conversion efficency. The equations of static displacement characteristic and force characteristic are derived, and the applicative conditions are given. The dynamical and force mathematic models of GMA are both established, and the dynamic characteristics are simulated by MATLAB. Based on deep analysis of simulation results, structure and performance parameters having affect on the dynamic characteristics of GMA abtained. The article analyzes the uniformity of the magnetic field, and simulates the axis symmetric magnetic field of the GMA utilizing ANSYS, and induces the mutative disciplinarian of the magnetic intension and the magnetic force line based on the different input current.The results show that the GMA for servo valve has the characteristics: simple, reliable and controllable. And also has large output displacement and force, good linearity, fast response speed, and its whole performance can be improved by adopting the pre-pressure exerted organization, offseted magnetic field controlled and increasing mount of additional magnetic loop.