Three-Dimensional Printed Wearable Sensors with Liquid Metals for Detecting the Pose of Snakelike Soft Robots

Liquid metal (LM)-based flexible sensors, which utilize advanced liquid conductive materials to serve as sensitive elements, are emerging as a promising solution to measure large deformations. Nowadays, one of the biggest challenges for precise control of soft robots is the detection of their real-time positions. Existing fabrication methods are unable to fabricate flexible sensors that match the shape of soft robots. In this report, we first described a novel 3D printed multifunction inductance flexible and stretchable sensor with LMs, which is capable of measuring both axial tension and curvature. This sensor is fabricated with a developed coaxial LM 3D printer by coprinting of silicone rubber and LMs. Because of the solenoid shape, this sensor can be easily installed on snakelike soft robots and can accurately distinguish different degrees of tensile and bending deformations. We determined the structural parameters of the sensor and proved its excellent stability and reliability. As a demonstration, we used this sensor to measure the curvature of a finger and feedback the position of an endoscope, a typical snakelike structure. Because of its bending deformation form consistent with the actual working status of the soft robot and unique shape, this sensor has better practical application prospects in the pose detection.