We built his project in 2018 with as a group of three students. We designed the simulator together and then divided up the roles for the rest of the project. Heather wrote our reports and kept the administration off our backs so that we could work efficiently. Garon did all of the fabrication. I did the wiring and programming.

The initial idea for this project came from Garon. He used to race outlaw carts, but a series of crashes and injuries made further racing unsafe. He wanted a way to get the thrill of racing without risking life and limb. I am still not convinced this is much safer, but it seemed like it would be when we started. The total power this platform is capable of putting out is more than the actual moving Baja Cart that another senior design team made.

This is a project I have continued working on over the years. We have made several changes to improve the performance of the platform and make it more user friendly. We ended up doing a complete redesign and the second version is currently under development.

• Garon Knudson - Design, Fabrication, Crash Test Dummy
• Heather Nelson - Design, Safety, Reports
• Robert Kuyper - Design, Wiring, Programming/Integration

This is the version that was developed for our senior design project. It was designed and built in an eight month period mostly composed of weekends. For testing we 3D printed a scale model to validate our geometry. The geometry we settled on met our motion requirements, but did not take full advantage of the motors and gearboxes we bought.

The control board was based on an Arduino Mega and was hand wired on perfboard. The startup leveling sequence was based on limit switches on each arm that set an upper and lower limit.

• Platform Trial
• Build Video

The year after our senior design, we allowed a second senior design team to modify our platform. This redesign only modified the upper platform which approximately doubled the range of motion. Unfortunately, while I was driving during testing the student on the e-stop did not press it when a motor stopped running and we severely crashed the platform. This bent several heim joints, sheered a tooth of in one of our gearboxes, and fried the control board I had made. I quickly drew up a new board and we ordered a custom PCB to replace the damaged board so we could limp through the end of the school year.

This was a repair to the V1.1 platform after our crash. Because the control board was burned out in the crash and we were running on a hasty replacement, we upgraded to an off the shelf controller with a lot more built in safety features. We also switched over from an Oculus Rift to a HTC Vive for our VR headset. This allowed us to implement motion compensation that subtracts the platform motion from the view movement. Motion compensation helps keep the user view from jumping out of the car and removes a lot of shake from the camera.

Because of the relatively short period of time we had to settle on a design for the V1 platform, we made several compromises that limited the range of motion of the simulator. These limitations were due to pinch points in the control arms. The V1.1 platform helped alleviate some of collisions, but the original design was still fundamentally flawed.

The goal of this redesign was to re-use all of the electronics and arms from the V1.2 platform and replace the upper and lower frame to remove pinch points entirely. In order to get the most possible range of motion, custom heim joint spacers were designed to allow our rod ends to have more range of motion than anything currently available on the market. Without the pinch points, the range of motion is limited only by the length of the arms and the angular limitation of the heim joints. The final motion envelope will provide approximately 18 inches of heave, 12 inches of surge and sway, and 45 degrees of pitch, roll, and yaw.

To improve safety, the ends of the arms are now captured by the frame. This prevents the arms from detaching completely from the platform if any of the bolts fail. To improve usability, the top platform is now easily removable to allow the cockpit to be use on or off of the platform.

The design is finalized. Garon is fabricating the new frame. The custom spacers have been sent out for manufacturing. I am moving all of the wiring into a new control box.

• Do not trust emergency equipment to people that do not understand the scope of the project and what failure modes look like.
• Create actionable safety documentation with explanations of failure modes and recovery procedures.
• Do not push untested code to hardware large enough to kill you without a reasonable exclusion zone.
• Place electronic components in a locations you can clearly see what you are touching.