Collision force suppression by human friendly robots with passively movable base

Presents the human safety mechanisms of a human friendly robot (HFR) capable of coexisting with human beings. In order to realize human safety, the HFR is required to be composed of an elastic material-covered manipulator and a passive viscoelastic trunk mounted on a passively movable base like a human's structure. During an expected or unexpected collision/contact between the HFR and its environment, the produced collision/contact forces are extremely attenuated by the combination motion of the passive viscoelastic trunk and passively movable base. The collision-tolerant control algorithm has been developed for the end-effector of the HFR to maintain its desired task during the expected or unexpected collision. Results of collision experiments show that the compliant trunk and movable base are effective mechanisms of suppressing collision forces, and the control algorithm is an effective method of positioning the end-effector.