Enabling Higher Performance Concentric Tube Robots Via Multiple Constant-Curvature Tubes

Concentric tube robots (CTRs) consist of a set of telescoping, pre-curved tubes, whose overall shape can be actively controlled by translating and rotating the tubes with respect to each other. The majority of CTRs to date consist of piecewise constant-curvature tubes, with a straight section followed by a single constant-curvature section. Several approaches have been proposed for CTR designs that can lead to improvements in metrics such as the workspace, orientability, dexterity, and stability. Here we propose to use CTRs with multiple constant-curvature sections. We perform two simulation studies that compare the performance of the multiple constant-curvature CTRs with standard single constant-curvature tubes. We also demonstrate how using one of the proposed multiple constant-curvature designs can enable the reduction in the number of tubes needed to achieve the same performance as a standard three-tube CTR.