Virtual nonholonomic constraint for human-robot cooperation in 3-D space

We discuss a robotic system that assists a human to carry a long object. The operator and the robot grasp each end of the object and carry it cooperatively. We extend the concept of virtual nonholonomic constraint to the motion in a vertical plane, in which the robot wrist behaves like a wheel and the operator can maneuver the object like a wheelbarrow. The operator and the robot can cooperatively lift the object to the desired height and inclination. Furthermore, we combine the vertical motion and the horizontal motion to carry the object to the desired position and posture in 3D space. The effectiveness of our method is experimentally confirmed.