Given the popularity of the 230/250 quads at the moment (blackout etc), I thought - wouldn't it be cool to have a rig that can do the ground skimming proximity stuff, but also with the normal "mod cons" of the APM?
Traditionally though, an APM would never fit. Until HK released the mini...so I built one.
I started with the Haldey-Bocks 230 frame, in Carbon Fibre. This was a mistake. I should have gone for the 250, because the fitting of the ESC's was a bitch of a job, especially with the thick 3DR power module hanging off it. And naturally, I forgot to solder in the XT for the video feed, so had to start again...
Anyway, this is the bare airframe:
So onto the fun part...
First, I fitted the camera, so I could make sure the clearances were good. I mounted it directly to the front CF plate to make sure I had as much room as possible behind it.
Second, I mounted the GPS antenna pole. This required a lot of trial and error, but eventually I found a position which worked.
Third, I fitted the APM mini in front of the post, and behind the camera. There is *just* enough room to do this. It is currently mounted with double 3M pads - I will review vibe damping after the first flight. Supposedly the blue balls do the "clean/dirty" thing, but is it enough to keep the APM within Z axis tolerances? Time will tell. These rcx are not the smoothest I have to say, and a propless spin up was really vibey.
I wired in the GPS, and the radio.
Then I mounted the 3DR telemetry radio to the roof. It is likely I will replace this with a minimOSD, and run a really simple OSD - volts, ground speed and home distance.
I then cable-tied the xt60 back on on itself on the PM - it was interfering with the props.
CoG is spot on, even though I thought it would be rearward.
Weight with tx will be 505 grams as you see it here. I have a wiring exercise to do (shorten and tidy), and to enclose the APM with some foam (for the Baro), and I hope that brings it down below the target 500 grams.
And that's it! It all fits together nicely. All the normal calibrations done - just compassmot to do (want to wait until I've got the camera and tx wired in first). Going for a really small 200mW 32ch 5.8. Will fit perfectly.
I didn't have time to get the thing in the air, but should able to get it in the air at the weekend. Can't wait to use DRIFT on this...:-)
Comments
:) looks like we are making some progress on TPA for us mini guys
https://github.com/diydrones/ardupilot/issues/1261
Shoot. Just wrote a post and deleted it. Take 2:
My team and I are launching a 3mm near-indestructible, solderless frame for FPV racing. The frame offers modularity for full sized electronics and flight controllers that need more room. (Something we learned when trying to cram all the APM bits into a regular mini frame) You can learn more about it here: www.dronekraft.io
We all adore the APM platform and spent a few years piloting larger rigs using every feature we could and fell in love with everything the platform offered.
When we started our design, we intended to fly APM – but were not able to tune and attain the same level of the other boards. We tried rigs, IMAX@1800, LPF filters, PIDs galore – but even with everything dialed in, the APM still felt wobbly and needed over-correction.
We switched to CC3d and the difference was pretty dramatic. The naze32 as well. It just feels locked and tight. It feels like xbox. Dead on, no correction needed. Point at something, it stays there.
Here is a vid of the APM in rate mode (best we could do), you can see the wobble a bit, hard to explain unless you feel the inputs: https://vimeo.com/106234412
And here's the cc3d:
https://www.youtube.com/watch?v=cJTxqUcUdJQ
We miss the minimOSD. We miss simple flight modes for fun. We miss looking at our flight paths in google maps. Yes we can attain some of these features in other platforms, but not all.
We're going to get another APM build going next week and will be joining in the efforts to perfect rate mode. But still feels like the platform has a ways to go to compete with the other FPV boards.
Hope we can continue to help. Sure feels naked flying without the APM.
Here is our v1 proto with minimosd:
And our final design:
Do you have any videos or examples of this?
I would like to see how it can perform turns while in forward motion, or how well it can strafe, thanks.
More yaw control, less efficiency. Better for tight slalom courses than open wide ones.
It would look great with some body or fiberglass or something. Even carbon fiber would be better, it looks "not aerodynamic" at all.
Can you compare the V tail to the standard setup?
This was 3.2rc7, if I recall. This is my lunchtime blaster at work, so not had a chance to bump it to rc12.
As mentioned - apart from failsafes, flight modes and PID's I've changed nothing. The only additional is the use of a case, which has solved my baro problems, and now it loiters surprisingly well on factory PID's
So finally which firmware version you are using?
The LPF and also Imax value which seem effect on setup.
Please share since I love to have H250 quad with APM
Thanks
Things have moved on a bit, as my 250 is now a 250-vtail. :-)
The pack doesn't last long enough for autotune to complete, so it's tuning old skool. Still a bit to do to totally lock it in, but it's flying ok as is.
I make my H250 with mini APM and it has terrible roll vibration. I replace with standard APM and the same thing happen .
The same kit working perfect with naze32.
Please shared your setup , Thanks
Hi Ryan,
I couldn't see your pid values but there are two things that can effect this. One of them is manual tuned rate pids that are actually quiet unstable and limit the stab P value. The second is the Rate I and I max terms. You can increase the I_MAX term to 1000 or 2000 but be carfull on take off because you can load the I term up and it can cause the copter too lean for a very short time depending on your PID values. You can also increase the rate I term to be significantly higher than P. I have tested to 4x but haven't had time to look into it too far.
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