Whole-Body Compliant Control of Robot Arms Based on Distributed Flexible Tactile Electronic Skin

Abstract

Robots are now working outside of industrial fences more and more closely with humans. Safety is the primary requirement for intimate human–robot interactions. Contacts could happen at any and multipoints of robot. Tactile sensors have great potentials for contact sensing. However, their implementation for the whole-body compliance of robots upon unknown contacts is still challenging. In this work, a systematic solution is proposed. A dual-arm humanoid platform is constructed with distributed tactile sensors on its arms and body. Cheap and easy accessed resistive flexible tactile sensors are used. A data collection and signal processing system is developed for the sensing system with scalable capabilities. External contacts on the robot can be monitored by a visualized system. The multipoint contact force is calculated with the sensor positions taken into consideration. A PD controller-based compliant force control algorithm is proposed in the joint space of the robot. Particularly, a geometry-based force propagation method is introduced in order to achieve overall whole-body compliance of the robot. Experiments verified the whole-body compliance of the robot arms. Safety could then be maintained for frequent human–robot interactions.