MARIONET: An exotendon-driven rotary series elastic actuator for exerting joint torque

A cable-driven, rotary series elastic actuator named MARIONET (moment arm adjustment for remote induction of net effective torque) is introduced as a novel means to deliver torque to a joint. Its advantages include remote actuation, independent control of compliance and equilibrium, and in future versions, the ability to span multiple joints. This cable-driven, compliant mechanism should prove very useful in a variety of human-robot interactions. Here we present a single joint device evaluated in terms of its position and torque step responses, its ability to follow a minimum jerk trajectory, and its ability to create torque fields. Results show that this device behaves as planned with several important limitations. We conclude with potential applications of this type of mechanism.