Magnetostrictive actuating device utilizing impact forces coupled with friction forces

Abstract

This paper describes the mechanical model, the design and the fabrication of a magnetostrictive actuating device, which locomotion is inspired by the motion of the smooth impact drive mechanism (SIDM) reported by some previous researches [1][2]. The proposed device is different from the SIDM driven by a piezoelectric actuator. It is actuated by a micro magnetostrictive actuator using iron-gallium alloy. The new-style alloy, referred to as Galfenol, is an iron-based magnetostrictive material with magnetostriction greater than 200 ppm, a high relative permeability μr > 100 and a Young's modulus of ~70 GPa. In addition, Galfenol is machinable by conventional cutting techniques and can operate under tensile, bending and impact loads without degradation in performance. Therefore, the magnetostrictive actuator using Galfenol will advantage our actuating device in design simplicity, low drive voltage requirements and high robustness. The proposed magnetostrictive actuating device is an interesting linear-moving mechanism, and takes advantage of impact forces coupled with friction forces so as to achieve a long stroke with fine positioning resolution. Experiments indicate that the maximum speed of the prototype is approximately 1.0 mm/s at the current frequency of 4 kHz.