Human-Robot Cooperative Manipulation Using a Virtual Nonholonomic Constraint

A robotic assistance system is presented which enables a human to handle unwieldy long objects by providing only one point of support. The robot grasps one end of the object and helps the human operator carry it at the other end. The proposed control method uses a virtual nonholonomic constraint. The movement of the object is constrained as if it were being carried on a wheel attached to the object. This method prevents the object from slipping sideways and simplifies the carrying operation. In spite of the constraint, the object can reach any position and orientation due to the nonholonomy. Cooperative manipulation in a horizontal plane is considered first, and then it is extended to 6-DoF manipulation in 3-D space. Experimental results show that an operator can easily handle a long object when aided by the robot.