A wire-driven continuum manipulator model without assuming shape curvature constancy

In this paper, we proposed a model for a wire-driven continuum manipulator without assuming constancy in curvatures of the manipulator's shape as a natural extension of the famous and useful constant curvature model. We show that the tip orientation of the continuum manipulator can be decided completely by pulling-wire lengths, regardless of its whole shape, which is a useful property same as the constant curvature model. Moreover, we can derive the tip position, which depends on the whole shape, by assuming distributed forces along wires mainly due to the friction between the wires and their surrounding materials. Experimental validation results show that, based on the model, we can estimate the tip orientation from pulling-wire lengths with good accuracy and precision. We also provide experimental results for discussion about estimating the tip position with the realistic assumption on the force distribution along wires.