A Measurement System Of GMA Internal Magnetic Field Based On Fiber Bragg Grating And Magnetostrictive Materials

Vibration isolation vibration reduction technology has very important significance in many fields, such as aerospace applications, deep gravitational wave detection, ultra precision machining equipment and so on. Nowadays people put forward higher request about this technology. Because of large expansion coefficient, high energy conversion efficiency and fast frequency response, the magnetostrictive micro displacement actuator based on magnetostrictive materials is of important position in active vibration isolation technology. However, magnetostrictive materials have typical h ysteresis nonlinearity and internal complex energy conversion and loss, which lead to the inaccuracy of actuator hysteresis model and energy attenuation of dynamic output. Research on actuator internal signal conversion process becomes the only way to improve actuator performance.This thesis focuses on combing FBG and magnetostrictive materials to establish a measurement system of GMA internal magnetic field. The main content includes the following four parts: 1. The sensing property of FBG and magnetostrictive materials has been analyzed, and the theory relationship of FBG measured value center wavelength with temperature and strain and Preisach hysteresis model of magnetostrictive materials have been established. 2. Strain transmission between magnetostrictive rod and FBG has been theoretical deduced and analyzed by simulation. 3. Establish the measurement system, improve the guide block structure of original magnetostrictive micro displacement actuator and simulate its effects. Double grating is used for temperature compensation to avoid effect by internal temperature changes. 4. Complete the part and whole experiment analysis of measurement system.Experiment results show the efficiency of strain transfer between GMM and FBG is 28.2%, and the optical wavelength demodulation system based on Sagnac fiber loop is stable with 0.1% floating range in 3 minutes and 0.72 pm wavelength resolution. With temperature compensation, measurement system is improved with stability of 0.14% floating range in 3 minutes, 111 m T wavelength resolution of linear measurement area, and 0.47% repeatability. The resolution of the endpoint/ intermediate region is 0.4/0.18 m T. This measurement system basically achieves the functionality for measuring internal magnetic field of magnetostrictive micro displacement actuator and has the potential for application in actuator internal signal measurement.