Design and application analysis of a novel tendon-drive flexible endoscope

Abstract

In this paper, a four-degree-of-freedom flexible endoscope based on tendon drive is proposed, which overcomes the disadvantage of insufficient flexibility at the end of the traditional endoscope, and provides a wider surgical visual field at the same time. This paper focuses on the study of its driving principle and control method. The designed flexible endoscope consists of a flexible arm and a drive box. The flexible segment is composed of 12 skeleton units in each series. The drive box, whose compact body makes the control process more flexible, controls the tightness of the wire through the bidirectional scrolls. Using the model with constant curvature, the motion principle of the flexible endoscope was studied, the mapping relationship among the drive space, the virtual joint space and the workspace was calculated. The drive control system design and drive algorithm programming of the flexible endoscope were completed, and the circular motion and linear motion of the end effector was realized. After experimental verification, the error of the master-slave control accuracy of the end of the four-degree-of-freedom flexible endoscope is less than 3 mm, the workspace is more than 100% larger than that of the traditional endoscope, and the maximum bending angle can reach 140°, realizing the advantage of a larger surgical visual field.