Collision-tolerant control of human-friendly robot with viscoelastic trunk

In this paper, a human-friendly robot (HFR) is described to realize human s afety, and a collision-tolerant control method is also proposed to achieve task performance. The HFR consists of an arm covered with viscoelastic mate rials and a trunk with mechanical elements, such as springs and dampers. In an unexpected or expected collision with a human, the passive viscoelastic trunk of the HFR passively deforms in response to the collision/contact fo rces. It is difficult, however, for the end effector to perform a desired t ask owing to the deformation of the passive trunk. In order to deal,vith th is problem, the joint configurations of the arm are directly calculated acc ording to the passive trunk deformation. The HFR,vith the passive viscoelas tic trunk is compared with a conventional industrial robot with a rigid tru nk for evaluation. Simulation and experimental results confirm that the pro posed control method is useful for the end-effector position control and th e passive viscoelastic trunk suitable for the suppression of collision/cont act forces.