Internal Pressure Measurement Method of Liquid-to-gas Phase Change Actuator for High Precision Force Sensing

Abstract

Pneumatic actuators have been applied to wearable haptic devices owing to their lightweight. However, the pneumatic actuators require an air compressor and air valves. Thus, the resulting systems are large and heavy. We have studied a haptic display using a liquid-to-gas phase change actuator. The actuator is composed of a thin plastic pouch containing a low boiling point liquid. A Peltier device controls the temperature of the liquid in close contact with an actuator. In this study, we embedded a small pressure and temperature sensor in the actuator and measured the pressure change induced by heating. The result indicates that the maximum pressure in the actuator is determined by vapor pressure, and a few tens of seconds are required to reach the maximum pressure.