A Capacitive and Piezoresistive Hybrid Sensor for Long‐Distance Proximity and Wide‐Range Force Detection in Human–Robot Collaboration

Abstract

Safety is a core concern in human–robot collaboration (HRC), which highly relies on multi‐information collected from its environment by various sensors. Current passive solution is to isolate the robot from human by fences or cages, which is invalid for a real collaborative robot, especially for the domestic and rehabilitation robots. Herein, a capacitive and piezoresistive hybrid sensor for long‐distance proximity and wide‐range force detection in HRC is reported. The sensor composes a pair of interdigital copper foil worked as the electrode for both coplanar capacitors and resistors, while a carbon black in polymer matrix works as the piezoresistive material. As‐prepared hybrid sensor can detect the object approaching as far as 100 mm, while a contact force covers from 0 to 450 N. The maximum sensitivity is 0.65 mm−1 for object proximity, and 17.73 N−1 for contact force. Significantly, the proposed hybrid sensor is feasible and scalable integration for the electronic‐skins (e‐skins) with superior stability, mechanical flexibility and deformability, which can withstand large compression, bending and torsion in applications. Finally, the e‐skins are used for safety control in two types of commercial robots, which exhibits the long‐distance proximity and large‐range force detection capabilities, illustrating its potential usage in complex, precise, and safe requirement conditions.

Keywords

• electronic-skins
• human–robot collaboration
• hybrid sensors
• long-distance proximities
• wide-range force detection