Design Analysis of Tendon-Actuated Soft Robot for Colonoscopy

Endoscopic-based double balloon represents an advanced technique for diagnosing and treating bowel cancer. However, existing designs face challenges including complexity and high cost due to the use of hybrid actuation, leading to prolonged procedure duration and patients’ pain. This article introduces a novel design of a multi-section soft robot actuated by cables. It is composed of two sections, each capable of bending in two planes. Additionally, the distal section can perform compression and extension. Four tendons separated by 90° are used to control the bending of each section. Each pair of parallel cables is attached to a DC motor through a double-groove pulley. Moreover, four independent cables are utilized to compress and extend the distal section. Finite element analysis is conducted to evaluate the performance of the prototype concerning its bending and displacement. Experimental validation is carried out to investigate the capability of the design in terms of bending and payload capacity. The results show that the robot can bend by more than 270° under a payload of 50 g. This paper represents the first phase for developing a soft colonoscope and relaxing the complexity of current designs.