A spring-like continuum joint for endoluminal surgery
File(s)
Author(s)
Li, Wei
Type
Thesis
Abstract
In endoluminal surgery, the endoscope is essential and it needs to be highly accurate and flexible to access the curved lumens. To improve its performance and functionality, a novel design of a metal-printed continuum joint is proposed, with the work mainly focusing on three topics: design, modeling, and insertion.
In this thesis, I will first introduce a novel continuum joint design that takes advantage of the spring-like structure, where the 1-DoF motion can be achieved by adding a series of circular contacts along the coils. Then, a snake-like flexible endoscope design are presented that consists of an active snake robot and a passive flexible body.
To facilitate the insertion of the endoscope, a novel endoscope design has an outer tube covered by a rotating screw-like sheath. The entire shaft of the endoscope can be actively rotated, providing crawling ability from the attached spiral sheath. Redundant control over the spring-like continuum joint allows the bending tip to maintain its orientation, assisting in endoscope navigation.
Taking into account the challenges identified in the previous robot designs, a new joint design inspired by the structure of DNA is introduced. It is acknowledged that compliant mechanisms using additive manufacturing are often affected by residual stress, resulting in defects like wrapping, twisting, and deformation. Several solutions are proposed to prevent these problems during the design stage.
Apart from optimising the additive manufacturing process, a new variable pitch design is investigated for the continuum joint. By incorporating this design into the spring-like structure, position errors accumulated at the distal tip of the joint can be reduced, especially at large bending angles.
The works presented in this thesis aim to solve the challenges encountered in robotic surgery. By exploring and refining the spring-like structure, various solutions have been investigated to improve the design and control of such flexible robots. The promising results make this structure a viable option for the next generation of surgical robots in endoluminal surgery.
In this thesis, I will first introduce a novel continuum joint design that takes advantage of the spring-like structure, where the 1-DoF motion can be achieved by adding a series of circular contacts along the coils. Then, a snake-like flexible endoscope design are presented that consists of an active snake robot and a passive flexible body.
To facilitate the insertion of the endoscope, a novel endoscope design has an outer tube covered by a rotating screw-like sheath. The entire shaft of the endoscope can be actively rotated, providing crawling ability from the attached spiral sheath. Redundant control over the spring-like continuum joint allows the bending tip to maintain its orientation, assisting in endoscope navigation.
Taking into account the challenges identified in the previous robot designs, a new joint design inspired by the structure of DNA is introduced. It is acknowledged that compliant mechanisms using additive manufacturing are often affected by residual stress, resulting in defects like wrapping, twisting, and deformation. Several solutions are proposed to prevent these problems during the design stage.
Apart from optimising the additive manufacturing process, a new variable pitch design is investigated for the continuum joint. By incorporating this design into the spring-like structure, position errors accumulated at the distal tip of the joint can be reduced, especially at large bending angles.
The works presented in this thesis aim to solve the challenges encountered in robotic surgery. By exploring and refining the spring-like structure, various solutions have been investigated to improve the design and control of such flexible robots. The promising results make this structure a viable option for the next generation of surgical robots in endoluminal surgery.
Version
Open Access
Date Issued
2023-04-14
Date Awarded
01/11/2023
License URL
Advisor
Lo, Benny
Publisher Department
Computing
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)