Multi-Modal Proprioceptive Sensors Based on Liquid Metal Capable of Self-Decoupling Measurement

In recent years, flexible sensing technology is rapidly developing due to the exploration of advanced materials and structure design. Multi-modal proprioceptive sensors are necessary for achieving accurate and intelligent manipulation of robots. In this paper, a liquid metal-based multi-modal proprioceptive soft sensor is proposed, which is capable of self-decoupling measurements of stretching, bending, and twisting. The structure of the sensor is composed of multiple liquid metal microfluidic sensing fibers. Through the spatial distribution of microfluidic sensing fibers, the sensor is able to detect multi-modal proprioceptive deformations. Upon the sensor undergoing deformation, the resistances of different microfluidic sensing fibers experience different changes. Multi-modal proprioceptive deformations can be decoupled by analyzing the resistance changes of different microfluidic sensing fibers. In addition, we further explore a simple, low-cost fabrication method. At last, the experiments demonstrate that the proposed sensor can effectively predict the proprioceptive deformation for soft actuator, i.e., stretching, bending and twisting. This self-decoupled multi-modal proprioceptive sensing method might pave the way for future intelligent soft robots.