HUMAN-ROBOT CONTACT IN THE SAFEGUARDING SPACE

In this paper, we discuss a human-robot (H-R) coexistent system which allows H-R contact actions in the safeguarding space mechanically boun ded by the human pain tolerance limit, The first half of this paper de scribes our study on the evaluation of the human pain tolerance limit which determines an individual's safeguarding space, We also show the human-safety-oriented design of a robot. The robot is covered with a v iscoelastic material to achieve both impact force attenuation and cont act sensitivity, keeping within the human pain tolerance limit, The ro bot, with simple direct-drive (DD) motor torque detection and emergenc y stop capabilities, automatically stops whenever any severe H-R conta ct occurs. In the second half of the paper, we propose a more efficien t H-R system, which allows H-R contact for improving work efficiency, as long as the contact does not exceed the human pain tolerance limit, For this purpose, a robot is controlled to reduce its velocity with h igh reliability at an incipient stage of its contact with a human. Thr ough experiments, we demonstrate the validity and efficient utility of the safeguarding space. The first experiment verifies that the develo ped robot exerts a contact force less than the human pain tolerance li mit establishing the safeguarding space. The second experiment compara tively shows the robot's velocity reduction to accept a safe contact w ith the human in the space.