Analysis of the giant magnetostrictive actuator with strong bias magnetic field

Abstract

Giant magnetostrictive actuator with strong bias magnetic field is designed to control the injector bullet valve opening and closing. The relationship between actuator displacement amplitude and input signal direction is analyzed. And based on the approximate linearity of strain-magnetic field, second-order system model of the actuator displacement is established. Experimental system suitable for the actuator is designed. The experimental results show that, the square voltage amplitude being 12V, the actuator displacement amplitude is about 17μm with backward direction signal input while being 1.5μm under forward direction signal. From the results, the suitable input direction is confirmed to be backward. With exciting frequncy lower than 200Hz, the error between the model and experimental result is less than 1.7μm. So the model is validated under the low-frequency signal input. The testing displacement-voltage curves are approximately straight lines. But due to the biased position, the line slope and the displacement-voltage linearity change as the input voltage changes.