For our 3rd year Engineering Design class, myself and a group of six other students were tasked to design a suspension system that would enable a six-wheeled robot to navigate speed bumps and accessibility ramps. The current design had two interior drive wheels, and four exterior casters for balance.
The old design makes movement easy to program, but runs into the problem shown in the diagram below. At the bottom of ramps, there is a zone where the motor wheel cannot touch the ground. A suspension system designed to fit with the existing robot would improve it significantly.
Wheel locations on robot 
The gap problem
We came up with three different designs to address this problem. Keep in mind that we have not taken any vibrations or FEA classes as this point, so there are certainly improvements that could have been made.
The design that I developed was called the “crawler”, due to its 8 wheels and rotating arms that allowed it to hug the terrain.
The other designs made by our team were the “swinger” and the “parallel trunnion”. Through a weighted objectives chart based on our objectives, the “parallel trunnion” design was selected.
“Swinger” 
“Parallel Trunnion”
For this project, we were to build a prototype out of readily accessible materials.
Unfortunately, we were unable to source any shocks (a spring/dashpot combination) for under the $150 budget assigned to the project. We instead got some gas dampers, which did not function as expected. They required a certain amount of loading before they actuated, then did not resist much after that point.
Another problem that we ran into was that the axle that a team member bought was aluminum instead of steel, which failed under the test loading of 100lbs.
Supports that would be added in an improved design. 
If we had time to improve on the design before the end of the course, we would have added supports on either side of the arm assemblies, sourced a steel axle, and paid the extra money for proper springs/dashpots.
If possible, we would also have bought all of the parts locally to avoid the large turnaround time we experienced.
This project helped me learn the value of prototyping and testing designs early, giving time to modify it when something doesn’t work. For my capstone project in 2021, I’ll use this experience to achieve a much better result!