Integration of flexible strain sensor using liquid metal into soft micro-actuator

Abstract

This paper presents a soft micro-finger composed of a soft micro-actuator and a flexible micro-sensor. Proposed micro-finger is, for the first time, integrated with a pneumatic balloon actuator (PBA) and a strain sensor using liquid metal. Both actuator and sensor can be formed by simple structures with cavities or channels sandwiched by two thin films. The strain sensor is fabricated by filling the space with liquid metal. Proposed design can provide simple batch-fabrication of integrated actuators and sensors for soft micro-fingers. We could succeed in detecting the motion of PBA (560μm×130μm×900μm) by the liquid metal based strain sensor (50μm×50μm×2mm). The gage factor of demonstrated strain sensor is estimated at 0.8. We can say the combination of proposed actuator and sensor is excellent in terms of both fabrication and performance.