Overview

I designed the chassis and steering mechanism for a rover that completed two laps around an obstacle course with turns, speed bumps, and a ramp while staying under a budget of $325.

Obstacle Course

Design Goals

We wanted to have:

  • High enough clearance to traverse the bumps and not get stuck atop the ramp
  • A tight turning radius for smooth and easy turning
  • Enough torque to climb the ramp

Initial Design

To meet these goals, I decided to use larger wheels for better clearance and a 52:16 gear ratio to balance speed and torque. The initial steering design had limited turning capability due to the wheels hitting the chassis. In the final design, slots were cut into the chassis to allow the wheels to turn farther.

Initial chassis design

Final design with cutouts

Final Design

Standoffs were embedded in the 3D printed pieces of the steering assembly, which were then screwed together. Washers were used to allow the pieces to rotate. During testing I found that the torque from the servo caused it to move itself rather than the steering mechanism. To remedy this, I cut out two pieces of wood to go on each side of the servo and clamp it in place. With this, the rover’s steering was able to work properly.

Holes for hexagonal standoffs

Pieces to clamp servo

Finished Assembly

Final CAD Model

Steering Animation

Completed Rover

Reflection

The rover was able to successfully complete two laps on the obstacle course, though the turning radius was not as tight during the second lap. This was due to the screws holding the steering together loosening slightly as the rover moved. I learned the importance of designing for manufacturability with the 3D printed steering assembly. Based on what I learned, I would design the steering to be simpler to reduce the number of points of failure.