Extended kinematic mapping of tendon-driven continuum robot for neuroendoscopy

We have developed and validated a new tendon-driven continuum robot for neuroendoscopy. The tendon-driven continuum robot has the outer diameter of 3.4 mm and two bending sections. We have also newly introduced an extended forward kinematic mapping (FKM) with attention to the hysteresis operation of the robot. The extended FKM maps tension in tendons to the posture of the robot as time discrete valuables, and evolves the previous posture to the present posture. Through this computation process, the extended FKM performs mapping with the hysteresis. We conducted articulation experiments with the tendon-driven continuum robot to test the extended FKM. We measured the postures reached from two different initial postures as the hysteresis operation, and assessed the prediction accuracy of the postures in comparison to the FKM in our previous study. In the experimental results, the extended FKM predicted the postures in the hysteresis operation with improved accuracy (the maximum position error: 1.6 mm by the extended FKM vs. 3.5 mm by the FKM over 60 mm articulation length).