Design of micro motors for ingestible medical capsule

• Main Author: Teoh, Boon Pin.
• Other Authors: Chen I-Ming
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Bioengineering; DRNTU::Engineering::Mechanical engineering::Surgical assistive technology
• Online Access: http://hdl.handle.net/10356/40661
• Institution: Nanyang Technological University

Capsule endoscopy is increasingly used in medical field for the diagnoses of gastrointestinal tract diseases, such as Crohn’s diease, gastric ulcers and colon cancer. The current capsule endoscopy has yet to provide medical professionals a complete and clear view of the digestive tract. The reason is because of the view angle of the camera is limited. To solve this problem, a micro motor is proposed to orient the camera so that it can capture a hemispherical view. In this study, piezoelectric actuator is selected to be the actuating element of the camera due to the various advantages that it has over other types of micro motors. The prototype design of the piezoelectric ultrasonic motor (USM) is also proposed in this project. In order to acquire the resonance frequencies and mode shapes of the piezoelectic actuator, modal analysis is carried out using ANSYS. To have feedback on the orientation of the rotor for the camera orientation, this project, a sensing system employing an optical sensor for the micro motor is suggested. Experiments are carried out to investigate the ability of the optical sensor to sense the spherical surface of the rotor. The results show that the optical sensing system proposed is able to trace the degree of rotation of a sphere of diameter 52.25mm about two principal axes which are perpendicular to each other. With the degree of rotation computed, we are able to determine the orientation of the camera.