Adaptive Update of Reference Capacitances in Conductive Fabric Based Robotic Skin

This letter proposes a sensor using conductive fabric that can detect proximity and contact by measuring the capacitance between the sensor and the surrounding environment. Due to the flexibility of the sensor used, it can be easily integrated with industrial robot arms to monitor proximity and contact between the robot and the surrounding environment including humans for safety reasons. However, the surrounding environment is constantly changing and significantly affects the capacitance measurements. To apply such proximity sensors in this scenario, the environmental variations have to be considered and the influences on the capacitance measurements have to be eliminated to ensure stable and robust proximity measurements. Therefore, in this letter, we propose an approach to adaptively update the reference capacitance to eliminate the influence of the environment. To experimentally validate the proposed sensor and approach, we developed a two-link robot arm and embedded the proposed sensing technology with each link. Experimental results demonstrate that proximity and contact can be successfully detected by the proposed sensor, independently of whether the robot arm is at rest or moving in a potentially dynamic environment.