Chapter 69 — Physical Human-Robot Interaction

A control strategy for human-friendly robots

The video shows the basic behavior of the system: A zero-gravity simulation with a Barrett Whole Arm Manipulator (WAM), a lightweight, 7-DOF robot driven by cable drives. The zero-G module applies the appropriate motor torques to counteract the gravity effects. The psychological impression is that the robot is completely passive although considerable forces are required for the gravity compensation. The robot is slowed down by friction only. In the second part of the video, the gravity constant is increased by 60%. This causes the robot to float up into a vertical configuration, as if the robot would be mounted upside down. (Video Proceedings of the Int. Conf. Robot. Autom. (ICRA), 1999)
Jochen Heinzmann, Jon Kieffer, Alexander Zelinsky