At last, I have something to share with you all. Some details as to how I mount my autopilot boards to my helis. Mounting these boards on helis has been a touchy subject, but so far I have had pretty decent luck. I am yet to experience 'the leans' with this method - the unpredictable variation of AHRS estimate caused by vibration. This also gives me a chance to show off my hand modeling skills ;)

Pictured below is my most recent build - the all new KDS Chase 360. Its a brilliant design by Aussie designer Glen Kimpton. The design itself incorporates a dual-stage belt drive train, which is unusual for a 450 class of heli. This means that not only can it handle massive power (my motor a KDE 459XF rated at > 725W continuous), but its also extremely smooth. The heli also includes an innovative battery tray, which 'clips' in rather than being mounted with Velcro.

The autopilot, a PX4FMU + PX4IO combo is both lightweight and powerful. It fits between the side frames with 1.5mm to spare either side. This one was a clone, which sadly dies with only 4 minutes of time in the air. Next board will be genuine for sure.

The mount was designed to bolt to the heli frame and then hold the board with foam two layers of tape from above. The board is then secured to the mount with a rubber band (not pictured) for added security in case the tape loses adhesive strength at the wrong time. I 3D printed the mount at 40% infill put of black PLA. I find that PLA is great for these mounts because it isn't as rigid as other plastics so doesn't seem to resonate as badly. I also like PLA because its extremely cheap and biodegradable - I can make hundreds of revisions and never feel guilty :)

Results:

The effect of vibration on the board is better than expected, logs showing approx < +/- 1g for xyz accelerometers in the air @3000rpm. Will upload a log to back this up.

Views: 2065

Comment by Mustafa TULU on October 26, 2014 at 8:54am

Hi, very nice job. Can you please tell me where did you get that form of px4. It would be very nice if you give us details about you setup like servos, frame, motor, and so on. Thanks.

Comment by Jolyon Saunders on October 26, 2014 at 1:48pm
Hi mustafa, there is info about my frame and motor within the post above. I'll post further details of my setup when I can
Comment by Jolyon Saunders on October 26, 2014 at 1:51pm
Also, that PX4 is available from several places, just search PX4FMU + PX4IO
Comment by Mustafa TULU on October 27, 2014 at 1:32am

That's excellent thanks.

Comment by gsenroc on October 27, 2014 at 2:26am

Nice place to mount a PX4 indeed! I'm a bit curious about the barometer, does it work well and not affected by the airflow?

Comment by Jolyon Saunders on October 27, 2014 at 2:31am
I never got a chance to test it properly, but I have always mounted my autopilots underneath between the skids. My helis have always performed extremely well in alt hold, so the baro performance seems OK.

I think the new position in the above photos should be OK as the chassis blocks most of the airflow similar to my other setups.

I have actually now mounted a Pixhawk on this heli because the PX4 bricked itself over the weekend. I'll post pics when its ready!

Developer
Comment by Craig Elder on October 27, 2014 at 5:02pm
Comment by Jolyon Saunders on October 27, 2014 at 5:44pm
^^ +1.

Of the 3 clones I have owed, all of them failed prematurely. Of the two genuine boards I have, one is 100% fine, the other was destroyed in a major crash (human error) but was extremely reliable, literally had hundreds of flights on it.

Needless to say the current build is using genuine parts.

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