Liquid Metal-Microelectronics Integration for a Sensorized Soft Robot Skin

Progress in soft robotics depends on the integration of electronics for sensing, power regulation, and signal processing. Commercially available microelectronics satisfy these functions and are small enough to preserve the natural mechanics of the host system. Here, we present a method for incorporating microelectronic sensors and integrated circuits (ICs) into the elastomeric skin of a soft robot. The thin stretchable skin contains various solid-state electronics for orientation, pressure, proximity, and temperature sensing, and a microprocessor. The components are connected by thin-film copper traces wetted with eutectic gallium indium (EGaIn), a room temperature liquid metal alloy that allows the circuit to maintain conductivity as it deforms under mechanical loading. In this paper, we characterize the function of the individual sensors in air and water, discuss the integration of the microelectronic skin with a shape-memory actuated soft gripper, and demonstrate the sensorized soft gripper in conjunction with a 4 degree-of-freedom (DOF) robot arm.