By this time during HyperXite III, all hands were on deck. Each subsystem had their plans and ideas on how to assemble their subsystem.
Stabilization (also internally known as Dynamic Structures), Braking, Electronics, Power Systems, Pneumatics and Fluidics (also known as Piping) and Structures then all needed to coordinate to determine how to assemble each piece.
Much planning went into creating each unit of the subsystem. The “tuning fork” looking pieces from the previous post isn’t shown here, unfortunately. The subsystem members mentioned the problematic part was obtaining the wheels that had the proper lubrication (the lubricant needed to survive near-vacuum conditions) and pinning down the right off-the-shelf size bushings for each component.
Mechanically-speaking, this subsystem was undoubtedly one of the most difficult to create and assemble. The goal of this subsystem was to properly stabilize the pod to be both centered on the Hyperloop rail, dampen the many bumps encountered on the track when the pod is traveling at its top speed, and allow the pod to make wide turns.
Much of this verification of this design was to be done during Testing Week since our team didn’t have the proper tools to test the fully assembled units.
|Stabilization Mounting||Component Mounting|
Premade holes were drilled out from our structure with the help from our Sponsors. Those holes were mounting the stabilization units, drive wheel assembly, and any other components like the battery container, solenoids, and electronics. Here are a few snapshots of us determining the correct mounting configuration we had set in place.
We were a bit surprised that each unit fit perfectly when mounting. Our engineers certainly put in the work to ensure each unit had a snug fit.
We thought of most things when mounting components. What we underestimated was the necessary wiring that was required to allow proper control of the pod. I’m exaggerating a bit though, the picture shown was when we were initially putting things together. The featured photo shown on each post displays much more tame wiring.
Also, I’d like to note in this photo that much of our needed electronics are located in the area shown. The IMU, shown in red, is mounted right above the center of mass of the pod, the CompactRIO controller is located not too far from the PCB, and our low voltage (high capacity) battery is near all the action to source the PCB with the necessary power.
Verification (and more testing…)
With a few days left we needed to make sure we had our design decisions jotted down. In this meeting, we were finalizing where we sourced our components to ensure we designed our subsystems to withstand our target speed. This information is crucial, because if we can’t justify why X component was chosen then for Y purpose, then our advisors would be a bit skeptical and might think that the component will be a source of failure.
Note that this meeting didn’t have every member participating, only a select few that were available at the time–it was an impromptu meeting.
Braking Subsystem Alignment
We had a few dozen feet of railing to test our pod’s movement and mounting. In this photo, you see the insides, or the underside, of our nearly finished pod.
Our pod was held up by upper stabilization wheels that consisted of custom springs, wheels, and components, and stabilized by “side stabilizers” shown at the bottom of the photo (blurred) that stuck on the webbing of the rail. What I want to focus on here is our magnetic braking unit.
The unit is in a “C” shape, where the magnets are on the upper and lower parts of the “C” configured in a Halbach Array pattern. Since the magnets are directly above and below the rail, the subsystem in its current state is considered engaged. This unit is particularly interesting because the pod can roll/move with the unit engaged, but very slowly. The braking unit counters movement, meaning if the pod was traversing at high speed, or if the metal between the “C” clamp were moving, the magnets would attempt to stop the movement via magnetic force. An advantageous and efficient method (although quite costly).
Although there was a problem, can you spot it?
The unit is perfectly center as is, and the pod has no load. Meaning, as soon as a significant weight was put on the pod, the unit would be slightly lowered–this is a problem. If there are any significant debris on the track, it may damage our braking unit, or our braking unit may damage the railing.
Luckily, when we mounted our components, we saw little to no difference in alignment. We just had to convey to our advisors that we were aware of this and it shouldn’t cause any issues.
Here’s a little bit more testing we did on our braking unit. We were determining how fast our brakes actuated with its preliminary configuration. As you can see it wasn’t very good at first–we needed it to be much faster. We switched out solenoid valves that had a larger release valve to allow for quicker release of air (the subsystem is pneumatically actuated).
2018 Hyperloop Competition (and even more testing…)
After months of planning, engineering, manufacturing and assembling it was time to show our advisors and other SpaceX engineers (judges) that our pod was able to be tested on the official Hyperloop track. This process is a week long, which is why it’s called Testing Week.
Competition weekend (after Testing Week)
This section is going to be a bit underwhelming. SpaceX prohibits teams from taking photos at the designated location (SpaceX headquarters) unless deemed OK from a SpaceX advisor. I am, however, able to share photos taken off-site and during Competition Weekend (when all the press is present).
Our team, like many others, stayed at an Airbnb not too far from the SpaceX location. There we did more of the finishing touches on the pod (you thought we were done, huh?). Most teams were like this–using up every minute given during Testing Week.
Our fairing finished drying, and some of the layers were becoming pronounced (explaining the black lines), and we needed to put the decals that displayed our team logo and sponsors. Our system engineer decided to take tackle this problem with some careful tape placement and polish.
Every subsystem is checked twice. Every. Single. One. We needed to ensure each component didn’t “shake off” under high-vibration conditions. Here we see our Electronics and System engineers ensuring the screws used to mount the inverter was set in place correctly.
Electronics and controls: this was our team’s breaking point. By far the most difficult to verify and test.
Our team encountered this odd problem where our control suddenly wasn’t able to communicate with our inverter–the CONTROLLER OF OUR MOTOR. Desperate, we took apart the inverter and probed various parts of the connector to see if there are any shorts or open circuits. We were stressed out. Luckily we managed to communicate with the inverter, but not reliably… which caused our team not to move forward in the competition.
The team unloading our equipment from the truck
Oh man, were we disappointed(at least I was). This competition is indeed not easy, but it is extremely rewarding. Every one of us learned a tremendous amount of engineering and design throughout the entire length of the competition: everything from design-for-manufacturing to business sponsorships and communications, to testing and verification. Every engineer on this team was took something useful away when completing the project, even if it was stressful at times.
After competition weekend the team rendezvoused at a location for a team dinner and then rested at the Airbnb. The following day we had to pack up our equipment, clean the Airbnb, load the truck with our pod, and drive back to UCI.
Back at the lab
So, where is the team now? Still engineering! We neatly unpacked our stuff back at our lab, so the next team (HyperXite IV) can continue the work! UCI HyperXite has become a well-established team, so-much-so that most of the members knew they wanted to continue onto next year. Subsystems can be improved, and I hope that next year’s team can fulfill those improvements.
Thanks for reading! I certainly enjoyed sharing my experience with a Hyperloop team. If you’re curious about HyperXite IV, see where the team is at here