Development of an innovative and compliant robotic wrist

This paper presents a recent study about a development of an original, cable-driven and compliant robotic wrist (ARTS wrist). The ARTS wrist presents two degrees of freedom; the mechanism is composed by two platforms connected by a thrust spring (working as a flexible joint) and by three cables placed and clamped corresponding to vertex of an equilateral triangle centred in the longitudinal axis of the device. The wrist is actuated by three motors, integrated in the device, and was designed to cooperate with the Cyberhand in reaching, handling and grasping objects. The flexibility of the spring is exploited to implement a compliant surrogate of a universal joint. The wrist performs the flexion-extension and the abductionadduction movements; the combination of these two specific actions creates composed configurations, as it happens in the human wrist. This paper presents also the mathematical model for the choice of the optimal spring used in the ARTS wrist.