I need some assistance. We are using APM2 on a DJI quad. We have a problem going into first flight. We have done all the ground tests such as levelling, CLI motor testing and ESC calibration (manual and automatic), but the moment that we give the system some throttle (one click on the stick) while in Stabilize mode, the motors go to maximum speed. We have repeated the levelling and the ESC calibration and have managed on 2 occasions to not get the aggressive speed response, but we could not repeat it. We have mounted the quad on a pivot to test the response, but there is no real control action on the motors. It is as if the motors are simply running at full speed.
Is there any constraint within the ESC calibration or other setup steps that we are perhaps violating that is messing up our setup?
Can any one help...pleeease?
can you post your parameter list and a flash flight log downloaded from the APM?
Check your radio calibration. If minimal throttle is acting like full throttle you might need to recalibrate.
Thanks, we have looked into that and it does not seem to be the problem. But, I am open to suggestions if we are missing something.
Jason (and Tim)
I have attached the log file and the parameters list. The log file was recorded for the following sequence of actions with the system in stabilize mode. The heli was mounted on a universal joint and being held level:
Thanks for the assistance.
Haha, I was about to post the same thread as I have exactly the same problem, and almost your same setup (APM1.4 and DJI frame). I just reflashed my esc's with simonk's firmware and I thought that was the problem but it works fine if I hook up the ESC directly to channel 3 on the receiver, so the problem must be on the code (V2.7.1 Quad).
This is in every mode (stabilize, loiter, alt hold) except in acrobatic. In that mode the motors are fine, so my guess is I should change something in the stabilize PID's, but I haven't figured out which parameter yet.
I'll continue digging to see what I can find, but anyone's help is really appreciated.
Ok, for some reason the value of P in Angular Rate Control was at 0.185, even though the recommended rates are between 0.145 (for small motors) and 0.090 (for big motors) so that value was way off boundaries. I assume the system was thinking we had super small motors and needed a lot of power to lift the craft. I changed the value to 0.145 as recommended and everything's fine now.
EDIT: FALSE! I was still in Acro mode when I was testing the results, so no, this is not the root of the problem.
The Stabilize Control P seems to do something with it. I change the value from 4.5 to 0.45 and the motors slowed down, but they were still too fast. I lowered the value to 0.001 and the motors slowed down a little bit more, but it remains too fast as well. And I don't know how much will this value will affect the performance of yaw, roll and pitch so I hope the answer is somewhere else
It seems like we have sorted out our problem. I am not sure which one carried the most weight, but we are flying.
The first thing we did was to reset the APM board via the CLI interface as we were not getting any control signals when we tilted the quad by hand.
The second thing we did was to reset the ESCs. It seems like we messed up the ESCs and put them in a wrong configuration during calibration.
Thanks for the assistance to those that offered it.