Torque control of a double tendon-sheath actuation mechanism in varying sheath configuration

Tendon-sheath actuation mechanism has been researched due to its extremely simple and light cable routing structure. However, the slide-based force transmission mechanism causes friction, which disturbs precise force control. To overcome such disadvantage, friction compensation algorithms in tendon-sheath actuation systems have been studied. However, the torque control of double tendon-sheath mechanism has not been achieved yet without a torque feedback. In this research, a double-tendon sheath actuation mechanism with series elastic elements and tight sheath routing method is introduced to achieve feedforward torque control. The performance of proposed mechanism is verified with experiments.