13.2.2 Design Process
Our approach to this project included iteration, beginning with broad brainstorming and gradually refining our design based on physical testing, material constraints, and system-level challenges.
Initially, our goal was to attach a Jansen linkage mechanism to a full-size skateboard. However, early in the process we realized that scaling to a real skateboard introduced significant challenges, particularly in terms of torque requirements and maintaining proper link proportions. As a result, we intentionally reduced the scope of the project and transitioned to using a toddler-sized skateboard. This allowed us to better match the scale of our mechanism to the available actuation and made testing more manageable.
Throughout prototyping, we explored multiple linkage sizes and manufacturing methods. We laser cut a set of linkages at approximately three-fourths the size of our original prototype to better evaluate motion while maintaining reasonable strength. In parallel, we also 3D printed a smaller set of links at half scale. After testing both versions, we found that the half-scale 3D printed linkages were better suited for the toddler skateboard, as they provided a more appropriate balance between size, motion, and required torque. As a result, this became the basis for our final design.
Our actuation strategy also evolved significantly. Initially, we planned to use a stepper motor controlled by an Arduino and motor driver. However, after spending several hours wiring and debugging the system—including verifying voltage levels and software outputs—we were unable to get the motor functioning reliably. Due to time constraints, we pivoted to a simpler and more reliable solution by repurposing a 12V DC motor from a previous project. This allowed us to continue testing mechanical performance without being blocked by electrical integration issues.
As we refined our mechanical design, we also made improvements to structural components. In our 3D printed parts, we determined that combining the A and L links into a triangular ground link significantly improved mounting. This design provided greater surface area for attachment to the skateboard and increased overall rigidity compared to our earlier configurations.
We also iterated on our gear design. Our initial gears were laser cut, but we found that they were too brittle and prone to failure under load. To address this, we transitioned to 3D printed gears, which offered improved durability and better performance during operation.
For mounting, we initially designed a fully 3D printed structure tailored to our original motor setup. However, after switching motors, this design was no longer compatible. Additionally, the print time for a revised version was estimated to exceed eight hours. Given time constraints, we opted to fabricate a mounting structure using wood, which allowed for faster iteration and sufficient structural support.
Ultimately, these iterative decisions—adjusting scale, refining linkage geometry, changing actuation methods, and selecting practical manufacturing approaches—guided us to our final design. Each challenge we encountered directly influenced our next steps, resulting in a system that successfully demonstrated the intended motion and functionality.