Well it's been a year since I built my first quad (selecting APM, naturally), and I've decided to do a bit of an upgrade in the off season, as is the tradition. There were four objectives to the exercise:
- better reliability
- simplify
- reduce weight
- improve performance
1. Better reliability
- added 40A ESC's, giving me 15A overhead (formally 30A on a 25A max draw)
- replaced 5V BEC with a 5.5V, after getting occasion chirp from spektrum telemetry about low volts.
- Re-wired the PDB and the ESC's for better RF
- replaced 1 motor that sounded less than optimal
- ESC's now uprated (if you can "uprate "to HobbyKing...:-)) and outboard for cooling and better security
2. Simplicity
- number of battery circuits reduced from 3 to one. New 5.5V and 12V BEC's used
- Unnecessary LED's dumped. Only retained 4 for orientation on the odd occasion I don't FPV. But they are braincube's and *very* bright! Here is the controller:
- Labelled everything
3. Reduce weight.
- Reduced battery circuits from 3 to 1.
- EzOSD replaced with minimOSD. Also in picture: an FPV camer switcher and the Telemetry junction box.
- LED circuits dumped
- Spektrum telemtry TM1000 dumped
- GPS finder dumped
- Leg components replaced with Carbon Fibre
And did it work? Starting weight: 3.65kg. End weight: 3.62kg. lol. However, if I'd stayed with the quadframe brushless (just refused to tune with a martinez board!) and dumbed the Braincube as well, I would have saved over 200g.
4. Performance
Ok, a big subject...
- Moongel replaced with zeal. Unfortunately vibes actually went up! I now hit the +/-5 "safe" limits in high power flight and maneuvers. However, it does seem to respond to very small commands much better; the zeal is firmer than moongel so I might expect that.
- PID's retuned after 3.0.1, to increase YAW control, and to decrease pitch/roll (only by 7%) to improve video footage. It still handles well, but it's now more "Transit" than "Cosworth" (for our american cousins, this translates to: "it's more light truck than corvette").
- 6S Current sensor added. Means Compassmot can be run in CURRENT not THROTTLE. Flight noticably more accurate, especially in RTL, Loiter.
- Higher GPS pole added. Compassmot reduced from 4% to 1%.
- Quadframe gimbal replaced with RCTimer, and video quality immediately improved. Quadframe brushless gimbal just refused to take a tune, and never performed well.
- Radio diversity added via Orangerx 800 (DSMX) + 2 sats. Each with a 30cm cable. One mounted far out under one arm, one as far down on the leg as possible. It's not perfect, but better than before. Radio now much more reliable regardless of orientation. No more scary moments...
Video TX moved to as far down the legs as possible. Range has improved from 350m to well over 600 with 600mw tx + ibcrazy omni's. Will be pushing out further, as I now have an ibcrazy 5 turn helical to play with as well. Also to come: 1/4 wavelength 433mhz antenna's for long range telemetry. How bad is it? It cuts out before the video does...
Gimbal has had 2 upgrades. I replaced the battery plate with my own design, and I'm happy with that. So happy I'm selling it to anyone who wants one. Also replaced the balls with stiffer ones. I still get a tiny bit of jitter in pitch, but I might need to look at my rx feed into the martinez; it might be noisy.
And finally, dumped the 420 line camera, and went with the 650 line from Security Camera 2000 (the one everyone goes for!). Along with some new low light lenses. Works so much better. Just a pity I can't get minimOSD to overlay on the feed for some reason; works ok on the Gopro feed!
What's everyone else got planned this winter?
Comments
Where did you find longer GPS + Compass wires ? Did you make them yourself ?
My copter is somewhat similar to yours and I plan to convert it to an X8 (a small tri is also planned and ordered)
Yes, it's thicker. I'll take a photo to show the difference (I have them both).
Interesting side note: I use them both on "terrence" (you've seen it). I use the 3m cut into 4, suspending a plate, onto which the APM is mounted with 4 zeal corners. Will upload vibe stats from next flight. Whenever that is - it's below zero now, here in Switzerland!
Where do you buy zeal online in Europe? Can't find any.
I'm using 3M vibration pad now. I get correct results but this 3M tape gel is only 2mm thick. Is zeal thicker?
Cheers guys!
@ Gary - wow, cool! Hope it helps others!
@ Hughes - these are still the original T-motor 2508-29's + CF 1455'. I've simply tuned THR_MAX to 920 to prevent me exceeding the maximum watt rating of these motors. I did some non-scientific test duing compassmot, and the last 10% of the throttle movement didn't really give any notable increase in motor rpm; it just seems to make the motors heat up much quicker.
@ Quadzimodo - yes! Everyone likes to do some building/upgrades in the winter months; this was just an incremental upgrade for me, but would be good to see what other projects are underway!
Fantastic post! Your workhorse is wonderfully resolved, and the coverage of it's evolution is just excellent! This project serves as a fantastic example of a sound development process for lesser experienced builders... like myself!
With regards to what the rest of us have planned this winter, I assume you mean in terms of similar personal projects?
Hi Euan,
You now have a new wiki page: http://copter.ardupilot.com/wiki/advanced-copter-design-and-methods/
Hope you like it.
Please let me know if there is anything you'd like to add or change.
Best regards,
Gary
Really nice copter Euan,
And thank you for posting the ongoing tuning details for it, very reasonable and very informative.
Interesting about the MoonGel / Zeal.
I have found MoonGel to be a bit too soft especially at higher temperatures whereas Zeal seems to stay the same regardless of temperature.
I suspect you fly in a colder area than I do, those big rotors are hard to vibration isolate in any case.
Great Job, could be well included in a wiki page on advanced copter design and setup - Hmm!
Interesting idea.
Best Regards,
Gary
nice
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