Design and Control of a Magnetic Hammer Millirobot for Tissue Penetration

Millirobots propelled by magnetic fields show promise for minimally invasive surgery or drug delivery. MRI scanners can generate magnetic gradients to apply propulsive forces on ferromagnetic objects. However, MRI gradient forces are insufficient for tissue penetration. This project presents a millirobot design and control methods to produce pulsed forces. A ferromagnetic sphere inside a hollow robot body can move back and forth between a spring and an impact rod. Repeated impacts convert the kinetic energy of the sphere into large pulsed forces that can penetrate tissue. An estimator helps achieve the maximum possible average impact velocity with minimal sensing, for a given set of material and geometric parameters, and input magnetic gradient force. Prototypes were 3D printed and tested on a custom magnetic test bed. Analytical, numerical and experimental results are presented.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Houston

Year dc:date.issued

2017

Author dc:creator

• Vichattumadom Ramakrishnan, Ashwin

Advisor dc:contributor.advisor

• Grigoriadis, Karolos M.

Committee members dc:contributor.committeemember

• Becker, Aaron T.
• Chen, Yi-Chao
• Tsekos, Nikolaos V.

• Medical robotics
• Robotics
• Minimally invasive surgery
• Force control

Statement dc:rights

• The author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).

Language dc:language.iso

eng

Handle dc:identifier.uri

https://hdl.handle.net/10657/4590

OAI identifier oai:identifier

oai:uh-ir.tdl.org:10657/4590