YOLO Handcycle
UC Davis Engineering Design Capstone Project
Team Members: Eric Schmidt, Martin Ward, Maria Celeste Castillo
Background
At UC Davis, our Engineering Capstone Design project was two semesters long. While many team projects involve corporate sponsorships, we decided to frame our problem and create the concept and goal for our project.
Project Description
Most commercial handcycles are designed for on-road use only. The few off-road models are aggressive, custom machines that often retail for over $5000. The YOLO Handcycle fits a middle market- it can go on easy to moderate off-road trails and costs around $1600. The YOLO Handcycle is designed with local Yolo county trails in mind, including the Putah Creek Riparian Reserve and Arboretum trails. We spent time familiarizing ourselves with the topic by sending out a survey to local handcycle users, speaking/ interviewing with hand cyclists, doing online research, and riding handcycles ourselves. Using a universal joint, we created an efficient way for the user to transfer power and steer simultaneously.
For the frame, we chose to modify an existing recumbent trike into a handcycle. We decided on the TerraTrike Rambler because of its relative inexpensiveness, tadpole configuration, adjustable upright seating, ample ground clearance, and tight turning radius. All of these traits have allowed us to design an inexpensive off-road handcycle. My main interest in this project was ergonomics and ease of use. We sent out a survey on handcycle features and received ten detailed responses from individuals with paraplegia. In this project, I learned the importance of creating precise design specifications and gathering customer research data to inform design. The surveys created and the time spent with local paraplegic people in Davis provided critical design insights. For example, we learned that the three main concerns were ease of transfer, ease of learning, and comfort for long periods. Consistently, we made these specs our top priorities. Our tests conclude that our handcycle is comfortable, easy to transfer in and out of, and easy to learn.
Reflection
This project was my first exposure to the complexity of gathering user data, and there were many practices to learn. The surveys themselves required a careful selection of features and questions. Then, when speaking to and watching paraplegic people, I had to be incredibly observant in finding unspoken needs and following up with specific questions relevant to our design. This project remains a truly important stepping stone in my career motivation in engineering: to build products that benefit other people's lives.
