On Tendon Driven Continuum Robots with Compressible Backbones

This paper discusses the effect of axial backbone compression on tendon-driven continuum robots. A new mechanics model for compensating for this effect that does not require tendon tension sensing or knowledge of manipulator material properties/stiffnesses is introduced and analyzed. In addition, we provide an analytical expression for the minimum preload on the tendons to achieve a given bend, a quantity determined empirically thus far. Our model is computationally efficient and achieves real time control on low cost hardware. The analysis is supported by experimental results demonstrating significant improvement over kinematics in open loop control of a tendon-driven continuum hose robot.