Path Planning of Long-reach Coupled Tendon-driven Manipulator

Tendon-driven mechanism enables to realize a long-reach robot arm to inspect in industrial plants. However, a large elastic elongation of tendons due to gravitational joint torque makes joint control unstable. In this paper, we proposed a planning method to search for a path that includes only stable postures. The stability of the joint angle was formulated using the balance between tendon elasticity and gravitational torque. As a planning algorithm, Rapidly exploring Random Tree was used. The effectiveness of the proposal was demonstrated by manipulation of 5 kg payload by 10-m-long robotic arm.