Robotic surgery procedures may include long, thin flexible instruments that are inserted by the robot into the patient. As the robot inserts these devices, due to their geometry, they are prone to buckling failure. To mitigate buckling failure, a support system is needed on the robot. This system supports the device but also adapts to the varying ex vivo length of the device as it is inserted. This work presents four collapsible support systems designed to mitigate buckling failure of long, thin instruments while accounting for changing length. The Ori-Guide is an origami-inspired system that has enabled a part reduction from traditional rigid systems with over 70 parts to 3 parts. This system was enabled through the development of a novel origami pattern that integrates both actuation and support into the same pattern. This system was made from PET and performed as well as a rigid system. The PET used in the Ori-Guide was thermo-processed to hold a folded shape. The heat treatment put the Ori-Guide into tension and enabled a stiffer support system. Work was done to investigate the effect of thermo-processing on PET films used in origami-inspired engineering applications. It was discovered that there is a strong correlation between crystallization and the stiffness of a crease in the polymer film. The Zipper-Tube Reinforcement (ZTR) was developed to provide constant support along the entire length of the device, something that no other support device provides. This enables higher loads on the device and thinner and more flexible devices. It was developed as a tube that envelopes the device and zips to provide a tube to support the device then unzips to lay flat rolled about a mandrel for storage. The Wires in Tension concept was developed by focusing on adding tension to the support system. It provided support to the device but required high levels of force on the robot arm so the Orthogonal Beams was developed. The Orthogonal Beams employs geometry as the primary support rather than tension and therefore could provide higher support with less force on the robot. These systems all proved effective ways to support flexible devices. The concepts could also find application in other fields. The merits of each system are discussed in detail, including a discussion on other possible applications.
College and Department
Ira A. Fulton College of Engineering and Technology; Mechanical Engineering
BYU ScholarsArchive Citation
Sargent, Brandon Scott, "Using Collapsible Systems to Mitigate Buckling in Thin Flexible Instruments in Robotic Surgery" (2018). Theses and Dissertations. 7341.
Compliant Mechanisms, Buckling, Lateral Stiffness, Robotic Surgery, PET, Origami