Document Type
Restricted Campus Only
Publication Date
4-2025
Abstract
This project aims to design, develop, and test a specialized prototype that will allow Calvin, a dog with mobility challenges, to engage in more advanced physical activities, specifically joining his owners, the Bacon family, on walks. As a puppy, Calvin broke his right front leg, which caused weakness and left it more susceptible to injury. Unfortunately, shortly after breaking his leg, Calvin contracted distemper, a neurological disorder. Because his right leg was already weakened from the fracture, the disease aggressively targeted and further damaged it. As a result, Calvin has severe difficulty moving and performing physical tasks. Over time, Calvin's left front leg has also become less functional, leaving him to rely solely on his hind legs for mobility. While he can propel himself short distances by using his hind legs, this method is inefficient and severely limits his ability to participate in everyday activities.
The goal of this project is to create a specialized wheelchair that will improve Calvin’s mobility and quality of life. We will develop several prototypes, refining the design with each iteration until we reach a final functional device. All work will be completed within a budget of $1,200, and if possible, materials will be sourced from the Trinity University Makerspace, where resources are available at no cost. The total weight of the device must be less than 15 pounds, similar to other wheelchairs available, and about half of Calvin’s weight. This is an appropriate constraint because Calvin will not bear the weight of the device when placed inside it; instead, the device will support him
The initial PVC frame prototype was developed during the first semester. Its design draws inspiration from existing dog mobility devices, which are typically intended for hind-limb or single-limb disabilities. While our prototype is specifically tailored to support front-leg mobility, it follows similar structural principles. After fabrication, the first subsystem test focused on evaluating the PVC frame. The frame underwent a series of assessments, including weight, drop, and connection tests. It successfully passed all evaluations, with the testing process and results detailed in the following sections. Based on the success of the initial prototype, the team elected to use PVC for the final frame design.
As the frame serves as the foundation for the prototype, playing a crucial role in its functionality and stability, the remaining two subsystems were idealized, fabricated, and tested after the final frame design was selected. For enhanced maneuverability and balance, the design incorporates a four-wheel system, featuring 6-inch diameter swivel wheels at the front and 3-inch diameter rigid wheels at the rear. This configuration allows Calvin to turn easily while maintaining stability.
For the third and final subsystem, the harness includes a two-piece system. The internal harness features a mesh design for comfort and breathability while securely holding Calvin’s limbs close to his body. The external harness includes multiple attachment points, ensuring Calvin’s weight is evenly distributed and allowing him to wear the device comfortably for extended periods without discomfort or pain.
Before testing the complete prototype, individual tests were conducted on each of the three subsystems. With safety as the primary concern, these tests evaluated specific performance aspects of each subsystem. Following subsystem testing, a series of comprehensive tests on the complete system were performed to ensure the prototype functions effectively.
After testing was completed, it became apparent that the device successfully meets the project's goals, as Calvin is now able to enjoy walks with the Bacon family. Although the device performs extremely well, one future consideration would be to incorporate a system that allows Calvin to be prepped for the device more easily.
Repository Citation
Jackson, Clayton; Anderson, Cole; Wagner, Trinity; and McAlester, Meredith, "Final Project Report: Specialized Dog Wheelchair" (2025). Engineering Senior Design Reports. 103.
https://digitalcommons.trinity.edu/engine_designreports/103
Comments
Dr. Keith Bartels, Team Adviser