I'm interested to know if anybody has used the Ardupilot/Arducopter on larger type frames over 650 mm? And if so does it perform ok?
I know that DJI say that for over 650mm frame size then it's necessary to go with their Wookong M flight controller to ensure stability and accuracy. Therefore I assume the Ardupilot would have the same limitations. Either that or the Arducopter parameters would require significant tweaking?
Anybody had any experience of this?
Replies
I've got a 780mm quad X config with MegaPirate NG 2.8 R3 and it's fine.
You can't use the standard configuration though, and depending on power/weight you may have to change the PID parameters a LOT.
Also you have to be much more careful with vibration and magnetic interference. You've probably got more power, bigger motors causing more electromagnetic interference AND vibration.
Tip, from my experience, adjust the power (motors, batteries) to the least that you will need for your missions. Maybe sounds obvious, but one should really almost take and engineered approach to this, not just spitting in the wind to see which way it goes.
Unfortunately my first one had huge motors and you end up with "Rocket Power Effect", more power, more batteries required, more batteries, more power required, more batteries required etc. etc.
A 750 size frame wishing to carry a load of 1.5 kilos, should not weigh more than 2 kilos (hopefully less) (total 3.5 kilos).
I lift off for instance with a total of 6 kilos aircraft weight, using about 220 Watts per motor. So 350 watt motors would be good for that weight, but even that weight gives you only 4.4 minutes on a 4s 4000Ah battery, so you'd really have to go to 4x4S 4000, getting 16 min or so.
If you can get your total weight down to 3kg including a 1kg payload, you should be able to get almost the same time from a single 5S 4000. Use higher torque disk motors, say 480 k/v for instance and bigger props like 15 or 16 x 8.
The configuration and capability of the software depends way more on the frame and ITs configuration than the size as such..
@ Jakey,
Just pitchin in -
Had APM 2 on two different heavy lift octocopter frames,
works wonderfully, lower rates as advised. flight is more stable
with full loaded craft, make sure you are using flashed ESCs
and be delicate with the controls -
this is the equivalent of flying a semi-trailer truck come airborne lawnmower!
Some other tips would be to use Ch. 6 to dial in the rates in real time,
and to use the "Auto Trim" function once you feel things are in place.
Also, keep the GPS+Magnetometer Away and ABOVE the motor plane,
as the magnetic fields will "hide" any satellites low or close to the horizon.
Various GPS mounts can be found on AliExpress.
:-)
Gil Rosenthal
I had good success with a Tarot Ironman 1000 + Tarot 5D Gimbal + Ardupilot 2.5 with 3.0.1. Lowered the PIDs and everything worked. The frame has a good weight balance using a NEX5n camera.
The APM doesn't care about how big or small your frame is. You will need to tune the APM to work with your frame (well motors really).
The APM could fly a small plane if you had a way to interface with the controls.
Henri