An articulated assistive robot for intuitive hands-on-payload manipulation

This paper presents an intelligent assistive robot designed to help operators in lifting and moving large payloads through direct physical contact (hands-on-payload mode). The mechanical design of the robot is first presented. Although its kinematics are similar to that of a cable-suspended system, the proposed mechanism is based on articulated linkages, thereby allowing the payload to be offset from the rail support on which it is suspended. A dynamic model of the robot is then developed. It is shown that a simplified dynamic model can be obtained using geometric assumptions. Based on the simplified dynamic model, a controller is then presented that handles the physical human-robot interaction and that provides the operator with an intuitive direct control of the payload. Experimental validation on a full-scale prototype is presented in order to demonstrate the effectiveness of the proposed robot and controller.