BiWi: Bi-articularly actuated and wire driven robot arm

Recently, there has been increasing attention on animal inspired robot arms equipped with bi-articular actuators. In this paper BiWi, bi-articularly actuated and wire driven robot arm, is proposed. The proposed manipulator is actuated by 6 motors arranged in three antagonistic pairs, so to reproduce the human musculoskeletal system characteristics in terms of joint torques and end effector output force production. The wire based transmission allows to place the motors away from the links reducing links inertia and increasing important factors as energy efficiency and safety. The proposed robot arm can produce a human-like force at the end effector by using a feedforward control strategy. Moreover, it is shown that the proposed manipulator presents perfect decoupling between mono- and bi-articular actuators joint torques thanks to the combination of antagonistic actuators and wire transmission.