Design of Giant Magnetostrictive Actuator for Ultra-compact EV: Fundamental Consideration on Frequency Characteristics of Magnetostriction Force

Abstract

Ultra-compact electric vehicles (EV) have recently begun to be sold instead of general vehicles with gasoline engine to new transportation recently. However, as the outer plate of an ultra-compact EV has low rigidity, the road noise that a tire generates by rotation and the wind noise generated by the projection shape of the vehicle transmit to the inside. It is thought that this interior noise deteriorates ride comfort for passengers. Therefore, we have been investigating a system for actively controlling noise transmitted from the outside with control sound generated by a giant magnetostrictive actuator on the ceiling of the cabin instead of a speaker installed in the vehicle. The control sound forms a wall in the cabin. The giant magnetostrictive actuator is required to produce sufficient thrust, less distortion, and delayed sound waves. In this paper, we studied giant magnetostriction force and performed a frequency analysis on the frequency of the harmonics generated when 100 to 500 Hz of control sound was output.