Micron Drone Design — April 2019
A lot has happened since we have made our previous design in March. We tested that design out and the arms ended up seeming pretty strong when we tried to flex them. Because the drone was a flat plate, we had trouble organizing wires and parts. This lead to some of the more delicate wires spontaneously coming undone or being cut. We ended up using zip ties (great for organizing btw) and painters tape to keep loose wires in place. When we tried to get Micron MK1 in the air, half the time it didn’t respond to throttle inputs and when it did, only one motor ended up spinning.
When we came back another day to get it working, we got it to fly once for a few seconds but we crashed the drone and an arm broke off. Luckily we had spares so we continued to try getting it to fly. For stable ground, we placed it on a table in a backyard. We successfully armed the throttle many times but we ran into the same problems we had the other day. Disappointed, most of the members walked inside and we disarmed the throttle, but out of nowhere, one of the motors span at full throttle and the entire drone flipped and crashed onto the ground. Our software VP was right next to the drone when this happened and his arm almost got chopped off by the propellers — however (luckily) nobody was hurt. Another arm and the propeller broke and we decided to fix the electrical glitches before someone got hurt.
A clip of the crash that gives us nightmares to this day: https://cdn.discordapp.com/attachments/563073278877630479/565023578232324096/video.mov
The reason for the crash will be in another article about the Navio2. It will be published shortly. For this reason, we have sold the Navio2 and we are planning to eventually purchase a Pixhawk 4.
While looking through the wreckage, we discovered that something very interesting had happened. The arms from both crashes broke at exactly the same place. This could not have been a coincidence. The arms must have been the weakest in that area. We checked our FEA simulations, and sure enough, it predicted weak points in those areas. They broke from a 2-foot fall which is unacceptable as nobody wanted to be wasting filament and time printing a new arm every time one breaks. We also wanted to make another design where wire management would be much simpler and would protect the expensive electronics.
We decided on a design where we would sandwich a stronger arm between two plates. The arm is shaped like a cantilever with a diagonal beam keeping the bulk of the arm upright. We spent an incredible amount of time and effort in developing this arm and it seems very promising on the sims due to the two-week-long friendly contest between Frank and Kai, two of our mechanical members. This arm is a lot stiffer than the previous one with the only drawback being that the entire frame is larger than the previous one. The larger design would provide more space for wire management so the drone looks cleaner and we know where all the wires are.
As of now, we do not have enough funds to purchase a Pixhawk 4 so we are planning to get a regular flight controller. Details about this will be discussed in a different article.
Hopefully, Micron 2.0 is successful. We will only be pursuing manual flight for this drone in the beginning. There will be a followup post on how successful Micron 2.0 will be so keep a look out for that. Until then, goodbye!
