Shape memory micro-actuation for a gastro-intestinal intervention system

This paper describes the design of a prototype gastro-intestinal interventi on system based on an inchworm-type of mobile robot. This type of device is a kind of vehicle for inspection through the colon, something that is curr ently impossible due to the large number of turns in the intestinal system. Eventually, tools for intervention can be added in the future. The overall system is about 95 mm long and has a diameter of 15 mm. The robot consists of three main modules: an extension and contraction module, a two degree-o f-freedom bending module and two locking modules. All these modules are to be actuated by shape memory elements. The main part of the paper describes a modular actuator for realising bending motion. The design can be compared to a single vertebra, where stacking several elements can form a spinal co lumn. It will be shown that this design greatly facilitates the control. Th e electromechanical interconnection of the different parts was an integral part of the design as well as techniques for selectively addressing the dif ferent actuators. In order to increase the performance of the proposed desi gn, the last part of the paper discusses some production aspects of the sha pe memory elements. (C) 1999 Elsevier Science S.A. All rights reserved.