Hey everyone, I’m wondering if anyone has experience tuning a large hexacopter drone. We have had difficulty trying to tune a large, heavylift drone. If anyone has developed a heavylift drone using PX4, I would love to connect and ask for your advice. Thanks.
Hey Ashura,
I have built several large Hexacopters (close to 25kg). The main problems I have faced are excessiv vibrations and finding the right PID sets. Please give me some more information about your drone, such as Motors, Airframe, FC-Mounting/Damping. If you have managed to do flight already, a log of the flight would be great.
Hi Ashura,
We build many large multi rotors up to about 50 Kg flight weight, and have gone as high as about 85 Kgs at this time. My first advice would be to go over to Arducopter flight code, much easier to use (and tune) and works well with heavy aircraft.
It is very difficult to give actual gain settings that will work for a different aircraft. Gain depends not only on weight, but also weight distribution, physical dimensions of the aircraft, and more importantly the reactivity of your drive. Reactivity is governed by motor choice, ESC settings, operating voltage, prop size and weight etc, so what works for one aircraft is no way guaranteed to work for another even if flight weight is similar. The faster the reactivity of your drive, the lower gain you need.
If you choose to go over to Arducopter and share some details of your aircraft we can probably give you some settings that will get you in the air (some video of where you are at now would also be very helpful), and from there a (slightly scary) auto tune would be your best bet. We actually tune on a special rig in the workshop and avoid tuning in the air (for obvious reasons) but if you don’t have this facility auto tune is about the easiest option to get the aircraft ‘tight’.
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Dear Alex Vulcan, I see that you have similar experience in very large drones. We have a very large one too 6 m wide and have some issues on the roll axis. It is OK for alt mode. But in loiter with payload it becomes sluggish in the role and with a roll stick movement it returns only to normal after a number of swings. Not good, If you can help us out I can give you all documentation videos, logs, etc… 
Hello everyone
I’m having the same problem. I have tested my all electronics on ZD850 frame first. Everything was good on that. But when I change my electronics to bigger frame my drone was not stable at all. It shakes very much as soon as it take off.
I’m using 6 X9 110KV motors( hexa copter ) of hobbywing. Motor to Motor diameter is 2.3meter. Currently our drone weight is approx 30kg.
This is the link of flight log I get :-
https://review.px4.io/plot_app?log=f9fa3e44-5090-4bfd-8803-7b2e22f4011d
From flight log what I’m able to found is that there is problem in magnetometer.
Please help me out if you have any idea of problem.
Thankyou.
Hello,
I suggest getting rid of the vibration going into your PX4 first. Seems to me that the main actuator output is working way too aggressively for that size of a drone.
To get large multirotors to fly well you need to turn down gain, and alot. Try the lowest settings, and start from there to move up in small steps. On lowest setting it will still fly ok.
For position flightmodes, there are numbers of diffrent parameters you need to work on.