Control scheme for human-robot co-manipulation of uncertain, time-varying loads

The collaboration between a human operator and a robotic manipulator for performing a joint task is the main topic of this article. One of the most common tasks involves transporting and positioning a load. The proposed control strategy allows the co-manipulation of loads with unknown, time-varying mass. The control algorithm is of a cyclic nature, where each cycle is subdivided into two stages. The first phase is the estimation of the human force, since the only connection between the robot and the human is via the load. In the second phase, a scaled version of the estimated human force is applied to the load. The proposed approach is illustrated by means of simulation results for a two-link robot manipulator.