Design and Evaluation of a Compact, MR-Compatible Origami Continuum Robot With Variable Length

Abstract

Continuum robots have recently gained attention for their great value in medical applications. This paper presents a novel design approach for MR-compatible medical continuum robots with the ability to variable length and controllable motion at compact size and light weight. The robot employs a small-scale origami continuum structure with an outside diameter of 15 mm, is driven by three tendon-shape memory alloy (SMA) actuators, and senses the motion of actuators by a thin linear potentiometer (Thinpot). The robot system is lightweight at 76.7 g and compact, with the proximal sensing and actuation module measuring only 34 mm in diameter and 90 mm in length. It is first demonstrated that the Thinpot is insensitive to magnetic disturbance and MR- compatible and can realize accurate feedback control of the large stroke of SMA actuators, even in a real 1.5T MR environment. Further, the bending angle and tip position of the robot can be controlled based on an inverse kinematic model. The robots equipped with different tools will show versatility in biomedical applications, such as endoscopy and needle insertion.