Abstract
Introduction
Orthopedic research and physical therapy rely heavily on animal models to understand joint mechanics and test rehabilitation strategies. Rats are a common subject due to their cost-effectiveness and biological similarities to humans in musculoskeletal studies. However, the use of live animal models raises ethical concerns and introduces variability due to biological factors. At the same time, emerging technologies like robotics offer a promising alternative, enabling researchers to develop reproducible and anatomically accurate models of joint motion. Both my technical project and STS research investigate different aspects of this broader issue: how biomechanical modeling using robotic systems can replace or supplement live animal models to improve research outcomes while addressing ethical considerations. This general problem has significant implications not only for orthopedic innovation but also for scientific practices in preclinical testing and translational research.
Technical Report Summary
In my technical project, I worked with my team to design a biomechanically accurate robotic rat hindlimb, focusing on the development of a functional ball-and-socket joint for the hip and 4-bar-linkage joint for the knee. This work contributes to the larger goal of simulating realistic rat gait patterns for use in motion capture studies and physical therapy applications. We began by analyzing bone models from micro-CT scans and identifying key degrees of freedom needed to replicate physiological movement. Using CAD software and 3D printing, we prototyped joint components with both rotational and translational motion. Iterative testing was performed to improve our kinematic accuracy and range of motion. Our team also collaborated to ensure proper integration with the robotic knee and foot systems, which were developed by a different capstone group. The result is a modular joint design that supports multi-planar motion and offers a foundation for future artificial muscle actuation or force feedback systems.
STS Paper Summary
My STS research investigates the mutual shaping of robotic models and animal-based orthopedic science, specifically asking: How does the development of robotic rat hindlimbs influence, and how is it influenced by, current practices in orthopedic research? Drawing from actor-network theory and articles on sociotechnical systems, I analyze how robotic technologies are not just tools but active participants in reshaping scientific knowledge production. I examine historical and contemporary uses of rats in biomedical research and compare them to ongoing efforts to replace live animals with mechanical analogs. Through interviews, literature analysis, and case studies, I argue that robotic hindlimbs co-produce new experimental standards and ethical norms, while still being constrained by expectations inherited from animal-based models. My conclusion is that while robotic systems hold promise in addressing ethical and translational limitations, they must be designed with careful attention to both technical fidelity and the institutional culture of orthopedic science.
Assessment and Recommendations
Together, my technical and STS projects provide complementary insights into the future of orthopedic research. Technically, we created a promising foundation for a reproducible and customizable rat limb model. The STS work illuminated how scientific tools, values, and practices co-evolve, suggesting that technological innovation alone is not enough, as cultural shifts in research ethics and validation protocols must also accompany it. Future work should explore control systems for the robotic limb, as well as its application in motion analysis pipelines. I also recommend further interdisciplinary collaboration between engineers, ethicists, and orthopedic researchers to ensure that robotic replacements meaningfully address both the mechanical and socio-technical demands of the field.
