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.