Snake-Like Units Using Flexible Backbones and Actuation Redundancy for Enhanced Miniaturization

This paper reports some recent analysis and modeling results obtained while developing a tele-robotic system for minimally invasive surgery of the throat. One of the main enabling components of this system is a Distal Dexterity Unit that implements a novel design using a flexible multi-backbone snake-like unit with actuation redundancy and push-pull actuation. The design of this snake-like unit is compared to other alternative designs that use a single flexible-backbone and wire-actuation. A unified kinematic and virtual work model is used to perform this comparison between a multi-backbone snake like unit with an equal-diameter snake-like unit using a single flexible backbone and wire actuation. The comparison is presented for several actuation redundancy resolutions that minimize the load on the flexible backbones. The results show that the multi-backbone design is superior to the alternative wire-actuated designs using a single flexible backbone. The advantages manifest in smaller required actuation forces on the backbones and, as a result, a reduced risk of buckling of the backbones and enhanced potential downsize scalability.