Electric Scooter Adaptation
September 2022 - May 2023
This was a project that I started working on as part of my Technology, Accessibility, and Design (TAD) course at Olin. I reached out to Erik Kondo, DIY adaptive technology and wheelchair scooterboarding expert, to ask if he had any projects that my team could work on with him. He proposed this project: adding a lift to an electric scooter so that wheelchair users could get full use by allowing them to lean into turns at high speeds. This enabled wheelchair users to access the full range of applications that electric scooters are designed to provide nondisabled people--everything from a fun toy to a practical transportation device. This project started as a team project for the TAD class, but I continued working on it on my own for an additional semester.
Erik Kondo has designed and built dozens of adaptive technology devices--everything from adaptive skateboards to specialized low-cost manual wheelchairs. I highly recommend checking out Erik's website and blog.
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I learned so much from Erik when I worked with him on the MoonWheel project at MIT's Assistive Technology Hackathon in 2020. So when I had the opportunity to work on a larger project as part of my Technology, Accessibility, and Design course, I reached out to Erik to ask if he had any projects he'd be willing to let a team of engineering students work on with him.
The project Erik proposed was for us to build a second iteration prototype of his wheelchair scooterboard--an electric scooter with a linear actuator attachment that lifted Erik's chair off the ground once he got up to speed so that he could use the full capability of the scooter without leaving his wheelchair behind. Unfortunately, the linear actuator couldn't lift Erik's wheelchair high enough for the rear wheels to clear the ground during tight turns at high speeds without becoming too tall for Erik's axle to clear when he was getting on the scooter. In this photo, Erik is riding the scooterboard with one of his wheelchair wheels removed to demonstrate the angle he needs to achieve to maintain balance on these tight turns.
My team met with Erik several times to brainstorm designs and make sure that we understood the design requirements correctly. He demonstrated his first-iteration prototype and explained the issues with it. You can find more information on the physics behind wheelchair scooterboarding on his website.
My team decided to use linkages in a half-scissor-lift design to maximize the height that Erik could achieve with it fully extended while still allowing enough clearance between it and his axle for him to roll onto the wheelchair with it retracted.
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We used 80-20 to build our frame because it is sturdy and easy to adjust, which would make it easier for Erik to continue modifying the prototype for a third iteration later if he wanted to.
We found a free broken scooter online and were able to get it working again by replacing the battery. We also added a dynamic control system so that the rider could adjust the speed. We removed the footboard and mounted the 80-20 structure to the frame of the scooter.
Throughout the process, we tested the scooterboard using a spare wheelchair that Erik had lent us. This helped us make sure that we had our dimensions right and that nothing was interfering unexpectedly. Most importantly, we used it to check that the axle cleared the cradle of the scooterboard lift when it was at its lowest position.
At the end of the semester, Erik tested out the scooterboard. It required a very impressive wheelie for him to get on it, but it worked!
Unfortunately, the scooterboard wasn't nearly as easy to use as we had hoped and also broke very quickly when Erik tried it out. Erik and I talked through some ways that the design could be better, and I asked if he'd be all right with me holding onto the scooterboard for another semester to keep working on it.
Most of my teammates studied abroad the next semester, so I continued working on the scooterboard on my own. Working on the scooterboard alone and in addition to all of my coursework severely limited how much progress I was able to make, but I was able to fix the major issues with the previous design. This photo is of the original design, and if you compare it with the photos below, you can see some of the changes I made.
By simplifying the design, I was able to increase the stability and maximum lift height of the device, while also significantly reducing the minimum height to make it easier for Erik to get on. At the end of the year, I gave the scooterboard prototype to Erik, along with all of the spare materials we had so that he could continue improving upon the design.
