Collision force suppression using a passively movable human-friendly robot

Abstract

The development of human-friendly robots (HFRs) is an important new field in robotics research. One of the most impotent functions of HFRs is not to inflict injury on humans during human-robot contact/collisions. With this in mind, this paper presents a safety structure of HFRs which consists of a manipulator mounted on a passively movable base. During an expected/unexpected collision with a human being, the movable base passively slips in response to the friction developed between the contact surface of the movable base and the ground. Due to the sliding motion of the movable base, the collision force produced is suppressed below human safety limits force; however, it is difficult to track the end-effector of the HFR. Therefore, in order to deal with the problem, a recently developed control approach is studied through simulations and experiments, which readjusts the reference motion of the HFR's manipulator according to the slipping motion of the movable base. Simulation and experimental results verify the effectiveness of the passively movable base for human safety and the proposed control method for task execution.