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
Tried 3.2rc5 (now already in Mission Planner beta), was also widy, lpf on 42hz, managed to complete autotune hooray :)
End result seems close to what I had except the very low D on the roll 0.0020 (was 0.0060) on the pitch its: 0.0120 (was 0.0150), not sure they are great PIDs as it was windy but I didn't get any oscillation with these PIDs while giving throttle.
Just finished a test flight with 3.2rc5 with my MPU 6k filter set to 42 Hz and all other PID settings the same as they were with the previous version (3.2rc3). I'm very happy with the results so far even with the 30k wind gusts that I was testing in. The quad feels much more stable now and I am able to better fine tune the D parameter without getting excessive wobbles. I tried Stabilize, Alt Hold and Loiter and all were much better than before. I'm looking forward to trying an autotune once the wind dies down.
Great job Leonard and Randy!!
Go to the parameters list and set your MPU 6k filter settings to 42 Hz.
Do an autotune and enjoy!
.....
Hopefully.
Please post your results!
Going to load it up and give it a try.
Just saw RC5 hit – does this include leonard's changes? I see some Acro_expo in the release notes. Getting excited. :)
Great timing, I have a 250 frame on the way right now. Thought I'd take a break from big copters and try some FPV. I was actually going to try and get a Pixhawk on it. Should be fun.
Great news Leonard. Looking forward to trying out the new changes. Has there been any more thought about the option to set a low throttle limit in ACRO mode or Stabilize mode so that you can reduce throttle to descend quickly with accidentally shutting the motors off?
Hi Shay,
You can still blow past the 45 degree limit in ACRO trainer, especially if you have low Stab P terms. The idea of the trainer is to provide a soft limit so if you let go of the sticks it will go back to 45 degrees where you have some hope of keeping the copter off the ground with the throttle or give you a little more time to switch to stabilize. In normal flight the trainer just starts applying levelling commands when you go past 45 degrees making it easier for the pilot when he overshoots the desired angle.
Sorry about the crash, I hope it gets back into the air quickly!!
Leonard, Thats great news!!
Already had 6 tuning sessions of complete 8 batteries. looking for number 9 with 3.2-rc5, when is that due? :)
Last tuning i actually did find out my PIDs were too high but not the place always looked but the stab P value, it was like the very high (9) value was fighting with the rate P, in order to compensate i had to raise the P of the rate, now I'm on roll stab P of 3.4 and it looks much better, trying again to get some Acro logs I crashed hard, had the Acro trainer on limit, why does it do 180 when the limit is 45? on fpv once i managed to fix quick, on LOS i had no chance.... after that crash and a quick field fixes (CA glue...) tried acro again and again a crash, I think that the only surviving prop from the first crash gave up... So tuning again tomorrow or just flying, it was too dark last time to see if the PIDs are as ok as they sound.
Again, thanks Leonard, waiting for RC5
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