Technical Systems · CAD · Fabrication · Engineering Constraints
CompletedNASA HERC rover steering
The RISD rover on the obstacle course at NASA HERC 2026, U.S. Space & Rocket Center, Huntsville, Alabama.
NASA’s Human Exploration Rover Challenge asks student teams to design and build a rover, then pedal it through an obstacle course and task challenges. RISD entered a two-person, human-powered rover.
I worked on the steering subteam. Steering on this rover is a set of interdependent constraints: it has to stay predictable while the suspension moves, leave room for the riders’ legs, clear obstacles, and hit a turning target. We resolved them over seven CAD iterations, tested two architectures with riders, and fabricated the final crank in carbon fiber. At the April 2026 competition, the RISD team placed second in the Human-Powered College/University Division and received the division’s Phoenix Award, which the team describes as recognizing the most improvement between reports, and its Task Challenge Award.
- Role
- Industrial designer on the steering subteam: co-design, fabrication, and technical editing
- Team
- Steering subteam: Wendy Tang, Ray Liu, Adhvik Aggarwal, Raúl Falcón; RISD Rover Team
- Tools
- SolidWorks, Fusion 360, 3D printing, SLS printing, carbon-fiber layup
- My dates
- September–December 2025
- Competition
- April 10–11, 2026 (team)
- Status
- Completed. Raced by the RISD Rover Team at NASA HERC 2026.
What I contributed
I co-designed the crank steering with the steering team and prototyped it through seven versions; managed its fabrication from SolidWorks and Fusion 360 CAD through 3D-printed mockups to carbon-fiber layups; and worked as a technical editor on the team’s NASA Design and Operational Readiness Reviews.
Constraints
Riders sit low, pedal under load, and steer through bumps and tight turns with limited visibility. Every steering constraint pulled on the others: moving a pivot for leg clearance changed the linkage path, and the linkage path changed how the wheels responded when the suspension moved.
| Constraint | What it demanded |
|---|---|
| Suspension interaction | Steering stays predictable while the suspension moves (no bump steer). |
| Leg clearance | Linkage and handles stay clear of riders pedaling under load. |
| Ground clearance | Pivots and links stay above obstacles on the course. |
| Steering angle and turning radius | Team targets: 50° steering angle and a 9-foot turning radius. The final geometry reached both. |
| Weight and stiffness | Stiff enough under load while adding as little weight as possible. |
Key decisions
Decision 1
Choose the crank, even though the handlebar felt better at first
Riders understood the handlebar immediately. But on our chassis it created tie-rod offset, packaging conflicts, and a risk of bump steer. The crank four-bar took longer to get used to, yet gave a cleaner linkage path and steadier response over rough ground. We recorded the comparison in a decision matrix and chose the crank.
Before · Handlebar
After · Crank four-bar
Steering comparison matrix Criteria Handlebar Crank four-bar Familiarity Strong — similar to bike and trike steering Moderate — riders needed time to adapt Packaging Weak — chassis geometry caused tie-rod offset Strong — cleaner linkage path Rough terrain Weaker — risk of bump steer Stronger — more consistent turning response Leg clearance Limited by chassis and rider position Improved over later versions Decision 2
Resolve one geometry conflict per version
Between version 1 and version 7 the geometry was rebuilt several times, and each change answered a specific problem: lengthening the side bars for more steering angle, raising the pivots above the center tube for ground clearance, integrating the side pivots into the chassis tubes, and moving them outward with dual handles for leg clearance.
Versions 1–7, annotated with the problem each change addressed. Left: 3D-printed prototype parts. Decision 3
Build for stiffness without weight
For the final part we used thin-walled carbon tubing for the links, lightweight PLA inserts inside the wet layups to reinforce high-stress joints, and SLS-printed bushings with shoulder bolts to keep the motion smooth under load.
Exploded view of the final crank assembly.
How the work moved
Understand the constraints, prototype cheaply, test with riders, diagnose what failed, change one thing, and validate it before committing to carbon fiber. We started with sketches and low-fidelity linkages, tested two architectures with riders, and only then fabricated.
Rider testing of the handlebar and crank prototypes.
Results
- The RISD Rover Team placed 2nd in the Human-Powered College/University Division at NASA HERC 2026 and took home the Phoenix Award (most improvement between reports) and the Task Challenge Award.
- The carbon-fiber crank steering I co-designed and fabricated was raced on the team’s rover.
- The final geometry hit both targets: a 50° steering angle and a 9-foot turning radius.
Team footage of the finished crank steering.
Why it’s in this portfolio
Rover steering isn’t technical art. What carries over is the way of working: many interdependent technical constraints, a loop of prototype, test, diagnose, and iterate, spatial reasoning in CAD, and documentation a technical team can build from. In a real-time environment the constraints become grid, scale, pivots, and frame budgets instead of chassis geometry.
Credits
- Steering subteam
- Wendy Tang, Ray Liu, Adhvik Aggarwal, Raúl Falcón
- Rover
- RISD Rover Team, Rhode Island School of Design
Placements and award names are from NASA’s announcement of the 32nd annual Human Exploration Rover Challenge winners. The Phoenix Award description is from the RISD Rover Team’s LinkedIn announcement.