University of California, San Diego
Mechanical and Aerospace Engineering
Sponsored by Dr. Jerban Saeed from UCSD Department of Radiology
Najmi Mohammad Hanis | Sujaan Mukherjee | Aden Wong | Rachel McClow
This project explores how dynamic medical imaging techniques commonly used for moving organs, such as the heart, can be extended to study joint mechanics. Rather than capturing a knee in a single static position, the goal is to repeatedly flex and extend the joint during scanning so that images collected at different angles can be reconstructed into an animated 3D visualization of motion.
To enable this, a scanner-compatible continuous passive motion (CPM) device was developed to physically actuate a rat knee inside a CT imaging environment without compromising image quality. The system is designed to produce controlled and repeatable knee flexion-extension while operating within strict spatial constraints and using materials that minimize imaging artifacts.
The initial implementation focuses on a rat-scale platform as a proof of concept, with the design structured to accommodate variations in limb geometry and remain adaptable for future scaling. The work brings together mechanism design, kinematic modeling, and system integration to bridge controlled mechanical actuation with imaging-based evaluation.
Description of Design Solution
This device uses a dual crank-slider mechanism that converts a rotational motion from the driving pulley to a rocking motion of the crank arm, allowing a continuous flexion and extension movement of the specimen leg.
Project Overview Video
Two mechanisms were prototyped: slider-rocker and linear rail. From the findings of this risk reduction we further refined our design.
Operation manual with assembly and troubleshooting guides.
Mechanical assembly walkthrough.