I Found a solution to the problem; I changed ESCs to Tiger Motor ESCs and changed the signal to 200hz.
More tunning on PID required, will try Autotune, however quad flies great on stabilized mode.
It is now clear that the problem is not related to PIXHAWK but to the ESCs and signal processing by the motors . As previously mentioned by experts in this Forum, the signal for Pixhawk is always the same and the controller is not the problem.
7/27/2015
Ok I accidentally sent a message to all the group, but I meant to make a clear declaration about PIxhawk.
For some reason, no one has ever found a resolution with the motor sync issue with some ESCs,( in my case with hobbywing 40a and 60a and the sudden loss of control of the Pixhawk due to signal malfunction with low RPM high pole count motors ( t motor 4008 380kv).
I believe it is important to mention, that after tunning, changing ESCs checking motors, and a few minutes of Stabilize and Loiter flight mode flight, switching to Pixhawk has been truly disappointing, and everyone should no that it will take some time to reach the " industrial" reliability and end user friendliness of the DJI Wookong M in the Pixhawk.
I believe it will be possible, but when there are potential to date unsolved issues, the community needs to be aware of them, in order to create proper expectations of Drone Builders and developers.
Pixhawk is completely incompatible with hobbywing Pentium 60 a and Hobbywing 40a ESCs. It Flips on necessary roll adjustments, and the motors are completely out of synchronization, even after adjusting RC signal parameters, PID adjustments, ensuring good connections, and checking motors and ESCs.
I truly hope the solution will be using DJI or T motor ESCs; however, there is a lot of people that are likely to try Hobbywing, or other brand high Amp ESCs with large motors, and my message is:
DON'T try it!!
You will spend more money, parts and time and brain power than simply using another controller.
Replies
Right.
@Pmarche: Hmm.. This is a very strong statement about Pixhawk.
Which software version are you running?
more details about your configuration could help understand what seems to be the problem.
(AUW, prop size, batteries, etc)
And for the dev team without log, it is just a guessing work.
Anyway, flying a number of heavy quads/hexa copters with large pancake motors AND Pixhawk I can say that once you get it right it is an exceptional flight controller.
separating power and sensitive electronics such as the pixhawk isa good idea I believe.
So using opto ESC or optocouplers in between the pixhawk and the ESCs improve a lot conducted noises.
This of course mean that a separate small 2S battery and a small 5 volts voltage regulator power the pixhawk. (clean power to the pixhawk).
I use opto Turnigy Dlux ESC and admit that they are doing a very good job.
Henri
Henri, I will provide Flying log files, of the failed-flipping flights.
Once again. my point was that the time, money, and experience required that one can spend when setting up Pixhawk with common ESCs ( assuming it will work smoothly after a careful initial setup and using autotune), could really be too much and frustrate a lot of people. That is why I believe by making a statement about it not being a RTF flight controller is important.
The problem with the wild flips, seems to be solved with T MOTOR ESCs, although I had to adjust the signal to 200hz
Pmarche, i'm facing a similar problem on different motor.
I try to dig down on the net and heard a lot of good things on hobbywing x rotor series.
Read the discussion here http://www.rcgroups.com/forums/showthread.php?t=2254658 and see if that solve your problem.
Great, this proves that is not the Pixhawk, is the ESCs. Pixhawk is great I have to accept. Just wanted to let people know about the problem.
That's good news; what esc do you buy?
T Motor 40A.
I have a T810 with Tator 4114 320KV motors and Hobbywing 40a ESCs and haven't seen any sync issues. I've flown several times and have tried to specifically reproduce the sync issues with rapid throttle changes and still no problems. I'm running an official Pixhawk on this one.
My previous setup a Tarot 680Pro with Tarot 620KV motors and 30a ZTW spiders V1 had no issues either and that was using a RTFHawk. When I put this setup together I also saw the reports of sync issues with the SimonK firmware, but didn't have any issues. When I had the Turnigy 30a ESCs on the rig however, I was able to reproduce the sync issues with ease. Since then, I've swapped out all the Turnigy ESCs with ZTW spiders and it's still flying like a champ.
I just Finished first flight in stabilized mode, it was great!. Problem solved with T Motor ESCs. Had to do some tuning, but no sync problems, and no FLIPS
It could also be a problem related to T-Motors exclusively. I am going to try today with the new ESCs. I will also Install the Firmware Marc suggests on Hobbywing. I will let you all know the results.
Again. my point on this discussion is not that there is something wrong with Pixhawk, I really like it, my point is that frequently, the signal incompatibility with some ESCs can cause unpleasant,costly in-flight surprises.
Testing in the ground typically is done once an accident has happened. It should be done with tape, as seen in many youtube videos.
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