Micro-vibration actuators driven by shape-memory alloy wires and its application to tactile displays

摘要

The authors have been developing a novel micro-vibration actuator using a shape-memory alloy (SMA) wire for the presentation of various tactile sensations to a human skin. An SMA wire has a unique characteristic to shrink to the lengthwise direction at a certain temperature according to the transition between the martensite and austenite phases. We have found a novel and characteristic effect that, by making the SMA into a fine wire with the diameter of 30-100 μm, it accepts a short pulse-current to instantly shrink and then return to the original length in accordance with the pulse frequency up to 300 Hz. The distinctive behavior of an SMA wire has been applied to present various tactile stimuli to human skin in this study.