COMPI: Development of a 6-DOF Compliant Robot Arm for Human-Robot Cooperation

Abstract :

This paper presents the compliant robot arm COMPI, designed having in mind some characteristics to make it suitable for human-robot collaboration: namely, compliance and lightweight. This should allow safe human-robot collaboration and contact with the environment without requiring external sensors or the delimitation of separate workspaces for robot and humans. The compliance in COMPI is achieved via active control by using a dynamic controller based on motor currents to estimate the joint torques (remarkably, the robot is using Brushless DC motors with gears of ratio 1:100) and making use of a experimentally identified robot dynamical model. The robot arm uses a distributed joint control approach in which each single joint is equipped with on-board electronics including computing power (FPGAs), power electronics and local sensors (e.g. joint position and motor phase currents). The experimental results show a very good positioning tracking performance as well as compliance to external forces.