Design of a SMA-actuated gastrointestinal intervention system

Abstract

This paper describes the design of a prototype gastrointestinal intervention system based on an inchworm-type of mobile robot. The overall system is about 95 mm long and has a diameter of 15 mm. The modular design has three main parts: an extension and contraction part, a two degree of freedom bending part and a locking part. All these parts are to be actuated by shape memory elements. Main part of the paper will concern a modular actuator for realizing bending motion. The design can be compared to a single vertebra, where a spinal column can be formed by stacking several elements. This design greatly facilitates the control as each elements is controlled in a binary mode. The design takes into consideration the electromechanical interconnection of the different parts and also techniques for selectively addressing the different actuators are discussed. For safety reasons, the first prototypes will be powered through electrical wires, which involves aspects of umbilical management. This type of device can be a kind of vehicle for inspection through the colon, something that is currently impossible due to the large number of turns in the intestinal system. Eventually, tools for intervention could be added in the future.