A Flexible, Tendon-Controlled Device for Endoscopy

Abstract

The high level of skill required to maneuver present-day, flexible endoscopes that are utilized in esophagoscopy and colonoscopy has prompted us to propose a new class of safer, more easily controlled devices. These devices are mechanical teleoperators with few degrees of freedom based on the famil iar bead chain with internal control cables. The study of the physics associated with the flexible control devices is carried out with respect to the design parameters of both the practical system and its envaronment. The suitable geometries for lock ing such a mechanism are presented herein. We introduce the "slide motion" scheme, which provides a smooth movement of the endoscope stem with only three continuously controlled degrees of freedom. Such movement is accomplished by imple menting a series of relative motions between an outer tube and intermittently stiff spines inside. The strength and stability of the locking mechanism, which exhibits intermittent stiffness, is also discussed.