7/8/2022 Taylor Tucker
Written by Taylor Tucker
Recent MechSE graduates Gabrielle Gebhardt, Michael Greco, Carol Guo, Chris Nava, Zheyu Zhou, and Diego Zuniga had a special opportunity with their senior design project: to contribute to turning one inventor’s dream of a motorized, all-terrain wheelchair carrier into reality.
Scott Darnell, who became a C6/5 quadriplegic following a diving accident in 1991, was accustomed to moving around the world for work alongside his father. Their work with Steenburgen/Hollanddrain trenchers included the installation of horizontal de-watering systems, patented by Darnell senior, at Disney World in 1974. They also worked on containment systems for chemical spills and hazardous waste around landfills. During their joint career, the pair installed approximately three million feet of gravity flow drainage in orange groves and other agricultural applications as well as systems for desalination in the San Joaquin Valley of California and areas around Faisalabad, Pakistan.
“After such an exciting start, my life has been reduced to sitting on the sidelines,” Darnell reflected. “Whereas my mind still wants to fully participate.”
Among dozens of other ideas for how to improve quality of life for those with mobility issues, Darnell envisioned producing an all-terrain wheelchair carrier that he came to call The Anywhere.
“I would absolutely love for those with disabilities in the future to never know everything that I have had to go through to forget this wheelchair beneath me,” he said of his struggle with locomotion.
Although off-road wheelchairs, which tend to be heavier and more robust than conventional power chairs, are currently available, they require users to transfer between chairs—a process that can be difficult, dangerous, or even impossible for many users to complete alone. As wheelchairs are often customized to the user, Darnell’s approach allows users to remain in the chair built specifically for their comfort and safety, making for a much easier transition than other available options allow. With a loading/unloading process that takes less than one minute, users can traverse previously inaccessible terrain as well as access and transition among restaurants, houses, and other facilities without ever needing to leave their chair. Future accessories are projected to address temperature and weather conditions as well as situational inclusion for users, allowing The Anywhere to better help those with disabilities re-enter life's playing field.
“The product development of The Anywhere is significant because it solves a problem many power wheelchair users face,” said team member Diego Zuniga, who will begin work as a Project Engineer at General Motors later this summer. “The Anywhere [will allow] the wheelchair user to roll onto it, strap in, and drive over any desired terrain, which will give many users much more mobility than ever before.”
In 2020, Darnell connected with ISE’s Teaching Assistant Professor Molly Hathaway Goldstein, who is also the director of the ISE Product Design Lab. Since its advent in 2007, the lab has served as a collaborative space for reverse engineering, prototyping, and modeling.
“I mentioned my wishes to work with universities to create an incubator-like system where I could hand off my products to business and engineering students to help bring them to fruition,” said Darnell, who has also collaborated with Greenville University. “[And] I relayed how much of an honor it would be for me to get to work with them.”
Goldstein connected Darnell with other ISE faculty, who then introduced him to Steve Zahos, MechSE’s Senior Design Project Coordinator.
“Steve has done incredible things to get one of my projects into the system and has also fielded requests for other projects I have waiting to be built,” Darnell said. “He has definitely been instrumental in finding and creating a niche to allow my participation.”
Zahos also connected Darnell with Damon McFall, MechSE’s Director of Facilities and Operations, and Teaching Assistant Professor Blake Johnson. The group collaborated toward the creation of the Wheelchair Mobility senior design project, which received a prototype of The Anywhere that Darnell’s team had already developed.
“I am personally grateful for the generosity of our department to make this project possible,” said Johnson, who instructs the senior design project course. Wheelchair Mobility was first offered as a project option for the Fall 2021 semester, during which time its team developed a more robust frame and suspension system as well as a pneumatic lift system for loading users onto the carrier.
The Spring 2022 senior design team’s goal was to advance The Anywhere prototype to be self-propelling on any terrain up to 12 miles per hour via joystick control. The project required analyzing the coefficient of friction for tires on rough surfaces—the three specified were loose sand, packed sand, and asphalt—then calculating the torque necessary for rolling over those surfaces. Battery capacity, ergonomics, and storage space were other considerations. Team members also incorporated differential steering to give the wheelchair both forward-backward and left spin-right spin motion capability.
“It was great to have a team coming from the same department with a lot of shared experiences,” reflected team member Zheyu Zhou, who will be pursuing a master’s degree focused on medical robotics at Johns Hopkins University this fall. “[At the same time], each of us has a different career passion, so our team got different experts on different topics.”
To test their circuitry and control design, the team constructed a scaled model. Control systems were also tested on the full-scale prototype without load. The total cost for the semester-long project was $2,625; next steps include reinforcing the full-scale prototype and testing under load.
For the Wheelchair Mobility team, The Anywhere’s progress summarizes a semester of hard work and thoughtful design. For Darnell, who hopes to find the right corporate partner to make The Anywhere available to as many potential users as possible, the carrier’s development holds even greater significance.
“I hope to one day fulfill a dream of traveling all of coastal Florida,” he said. “[This work also] leaves a pathway open for many more projects to be developed together in the years ahead.”