Robotic Arm

Abstract

In general terms, the present invention provides a passively compliant robotic arm having one or more variable stiffness joints controllable by first and second bi-directional actuators that can be independently operated. Each bi-directional actuator may be operable in a first configuration to urge the joint in a first direction, and in a second configuration to urge the joint in a second direction opposite to the first direction. The bi-directional actuators may be operated in a cooperating mode (high torque mode) in which they work in tandem (i.e. both in the first configuration or second configuration) to double the available torque output. The bi-directional actuators may also (or alternatively) be operated in a high stiffness mode (antagonist mode) in which they counter-act each other by operating so that they oppose one another (i.e. one in the first configuration and the other in the second configuration). The high torque mode may be utilised for an initial portion of a movement trajectory, and the antagonist mode for a final portion of the movement trajectory. The relatively high stiffness in the high stiffness/antagonist mode results from the combined effects of the non-linear force-deflection relationship of the first and second resilient members. The resilient members may each comprise an elastic element, tendon or other resilient member that can be stretched (elongated) to increase tension therein and thereby urge the joint to move.

Dependencies are inferred from the claim text.