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- Hacker News
- I do not notice that the time of posts is reversed haha. I am confused whether you had build it.
Thank you, it's cool!
by melagonster - Newest is at the top :D If you press the little "Collapse All" button on the top right of the blog posts, you can see the full timeline + dates of the entries.
I did start by designing/building a regular FC (no RL or anything) and am doing RL training afterwards, so I agree that the whole timeline looks a little confusing without background context since it goes real drone --> sim haha
by kar0lina - Will follow a fellow Polish inventor! :)
- Hi!! Would love to connect :) My X is karolina_dubiel and LinkedIn: https://linkedin.com/in/karolinadubielby kar0lina
- This is cool as sugar! I have to ask though, how many end mills did you go through milling G10 fiberglass and carbon fiber‽
I've heard the dust from carbon fiber is second to asbestos for inhaling.
- Also there was a video about touching the edges of carbon fiber where it is not surface treated is embedding countless small shards of carbon into your skin, only visible through magnification, which cannot be healthy..by faeyanpiraat
- Asbestos is dangerous not because it's asbestos, but because it makes small and sharp fibres that embed in the lung tissue.
Carbon Fiber (and even fibreglass) can make fibres that small and sharp. So yeah, responsible dust handling is key.
The good news is that Asbestos easily puts off those small fibres just by being handled. CF and FG need to be damaged or machined to do it, handling the material after the dust has been dealt with is fine.
by dghlsakjg - I love everything about this. Well done! but missed opportunity to name it R_of_L-copter.by geod_of_ix
- Kudos for such a great learning journey!by pjdkoch
- If I were to get a dirt cheap Chinese drone, would that be more likely to use RL or MCP? What’s the “standard”?by quibono
- Phrased in a slightly different way, assuming the standard is Betaflight/Ardupilot/PX4. (This article uses BF): Inner PID rate loop; this compares IMU-measured rates vs that commanded by manual controls. This might run at 1-4kHz.
On top of this (Maybe at a few hundred hz), you can add outer controls to set attitude. This could be an autopilot, or having the controls command attitude instead of rate. Betaflight pilots usually don't both with this, and have the simple setup of control maps to rate.
I've programmed firmware using a weird hybrid where the controls command a change in the target attitude. So it flies like rate, but has the forced attitude stability of an attitude-based control system. Non-standard, but makes it so you don't need to worry as much about tuning the PID loop. In practice, you can do full aerobatic flight with this like you'd do with a rate-only setup. (Basically, there is a commanded attitude quaternion; controls nudge it; the PIDs update motor power to maintain this commanded quaternion.)
- PID is more than enough to keep level. FPV relies on manual flight, but you can get Ardupilot for autonomous missions. There's no need for RL, nothing to gain here; level flight and following waypoints is a solved issue already.
And frankly as a pilot, I'd rather not see any completely autonomous drones with no oversight in the sky - that's one incident away in which blame cannot be put solely on the operator from getting the hobby completely banned.
by spaqin - Low end and most open source stuff will use a PID inner loop for “fast path” control (stabilization) and either a second PID loop or something a little better (Kalman filter etc) for the slow path (position / path hold).
Higher end stuff will use a ton of inputs (visual odometry, binocular vision, lidar, range finding, etc) fused into some kind of proprietary blended algorithm that you could probably call an MPC.
RL is pretty cutting edge, especially for fast path motor control; there are a lot of university competitions for drone control that lead to a lot of papers and projects in the space (some promising) but most commercial stuff has not adopted this yet, certainly not at the low end.
by bri3d - Cool project! For a DIY beginner, what would be a good starting point for a "normal" drone/octocopter project?by lhaussknecht
- Hi, thank you!! There's so many great resources for building your own quad from scratch (ex https://www.youtube.com/watch?v=S9dvDU5RmQU&t=476s). I honestly wouldn't recommend an octo unless you have a reason for it (like wanting more fault tolerance, etc) solely because it's twice as expensive for the motors. I got all my parts from GetFPV and Amazon. At the very bare level, all you need is a FC, ESC, frame, props, motors, receiver, and battery (plus controller, and goggles/camera if you want it to be FPV)by kar0lina
- I find it very hard to believe that someone who has never done any CAD could design that with Fusion 360 in a day. I do lots of 3D design with Fusion and there is a serious learning curve. It's not something you can pick up in a day. She is doubtless much smarter than me, but that's not credible.by urban_winter
- Did you look at the parts and content, or just leap to this assumption?
My first couple days with Fusion had similar outcomes, and this is totally credible. There are extremely talented YouTubers that have information-dense guides through many features. It's totally plausible with that and having a mentor showing you a tool to succeed here.
Why add negativity to something cool? There is a build log! It's well done and tangible! It's not slop! Celebrating is always more fun than humbugging.
by _jss - Hi, I’m Karolina! I get it!! I’d probably have some doubts if I saw this online too.
To be fair, I definitely did not get good at Fusion in a day (I’m still not very good at Fusion). The Day 1 CAD was all flat shapes -- all I had to do was use the line, curve, and pattern/mirror tools and then extrude those shapes to my body plate / arm thickness. Same with the screw holes -- I didn’t know there was a hole tool and was just drawing circles, patterning them, and extruding them backwards. It still took me forever, I started super early in the morning and worked on it until ~2pm, knowing it would probably take a MechE major 30 mins to do the same thing.
I also do have mentors in the form of eng majors who can give me verbal feedback / advice / show me which tools to use / get me unstuck. To me, it was very important that I was the only one actually doing the CAD so I could learn, but I definitely have had super amazing mentorship along the way to teach me and point me in the right direction. The motors and props are just 3rd-party components that I imported (still took me ages to figure out how to constrain them right). I went to the machine shop after and that took forever too, especially figuring out how I’m supposed to arrange the plates for printing in Fusion (but I had people to help me out there, they were not going to let me use a CNC mill alone with no exp lol)
I made the GPS / receiver mount way later in the process because I was so intimidated by the CAD for it (literally taped my GPS and my receiver to the drone for the first flight instead), and it took me days (also such a simple component, but the stuff that’s not just an extruded 2D shape is way harder for me).
I’m definitely not superhuman and it’s probably going to be years before I feel truly confident in Fusion :))
by kar0lina - Amazing: I'm watching lots of homemade builds atm.
I've got a question: why CNC milling and not just FDM 3D printed parts? TFA doesn't talk much about it except saying she went to a machine shop.
> 2. CNC milling forms out of G-10 fiberglass (arms) and 5mm carbon fiber (body)
TFA also says this:
> The solution for this is to 3D print a 0-tolerance assembly jig to hold the arms in perfect position while the center of the drone is superglued together.
Why not 3D print it all?
There's this guy who built a drone that can fly for 3 hours and cover hundreds of miles, 3D printed at home on a $250 printer:
Then there was the $200 K quote for the body for a car that just did Pike's Peak with a four times Pike's Peak champion and instead the team... 3D-printed the car's body at home (something like 40 parts, assembled together), which cost them less than $2 K to make (1/100th of the quoted price for the car's body). Here's the vid where they print all the parts (on a $1500 consumer printer):
Basically: why CNC milling and not 3D printing at home when many drones enthusiasts (and now too people building race cars) simply print parts at home on a consumer-grade 3D printer?
- Stiffness. Important for how the frame behaves under load and buffetting etc.
- 3D printing isn't stiff enough for a larger drone like this, you'll get flex which will upset the PID loop and cause it to be very unstable if it even flies at all.
You'll notice on your 3D printed drone link that the actual multirotor part is carbon fiber tubes. The motor mounts and other brackets can be 3D printed without issues.
by Saris - For "copter" style drones, 3D printing is basically a "noob" meme at this point; everyone thinks it's a good idea, tries it, and realizes that it's actually really hard and doesn't work.
Copter-style drones are exposed to vibration across a huge frequency range in every axis, and it's almost impossible to avoid really nasty resonance issues using generally-printable FDM filaments and "standard" design techniques; it's a lot easier to just use super-stiff carbon fiber and CNC it.
For planes, like what you linked, 3D printing is more "plausible" than for copters but also not really practical; you can 3D print a good plane, but plastic lacks the durability and favorable weight characteristics of foam - plastic planes tend to be "one time crashed" while foam is easy to repair, restore, and rebuild.
by bri3d - Something I've wondered for octocopters - could using a ring instead of arms be beneficial for weight? 6.28r < 8r, but then again the arm radius is usually less than the full circle, and some components want to be centrally located, etc. I could imagine holding the central components in tension via light filaments (carbon fiber, nylon, etc) in tension, vs having to have rigid structure, but the small factor between 6.28 and 8 and maybe makes it not worth it.by Tossrock
- consider "tiled" hexagons, like honycomb.
large schedule 40 or 80 tubing sliced into rings would be pretty quick source material, starting with duct tape and zipties until you find a good arrangment then get into the glue and screws.
by rolph - This is very impressive! I researched fault-tolerant octorotor control using RL in grad school for a NASA project. Perhaps this may be helpful[1, see section 8.3]! The field is moving fast, so there may be better or more suitable approaches out there now.
For folks who are interested in UAV physics, I wrote up an explainer[2].
[1]: https://drive.google.com/file/d/1RTEVRd0XCWLuDXY2nkbmYuOaa5x...
by hazrmard - This is lovely, thanks!by quibono
- Hi!! I'm Karolina, and this is my project! Had no idea this got posted until someone DMed me about it on LinkedIn. Feel free to ask any questions or follow along via X (karolina_dubiel)
Thanks so much for all the kind words, it means a lot!
by kar0lina - You seem very talented, great work!