Human-Robot Cooperative Handling of a Long Object : Control Method in 3-D Space Using Virtual Nonholonomic Constraint

This article describes a robotic system that assists a human to carry a long/big object in 3-D space. We assume that the operator and the robot grasp each end of the object and carry it cooperatively. In this task, it is difficult for the human to give a translational force at the robot hand by a torque control. Therefore, we propose to assign a virtual nonholonomic constraint to the robot hand. In this method, the robot behaves like a unicycle and we only use translational force to manipulate it. The controllability is assured based on nonholonomy and the operator can transport the object to the desired position and posture in 3-D space by similar skill using wheelbarrow. The effectiveness of our method is experimentally verified.