Greetings!
Before I am going to install APM in an airframe I wanted to get a bit more familiar with its control behaviour. I did all the testing and radio calibration without any problem and I am now doing some workbench testing of the bare APM (w/o GPS, airspeed sensor, etc). However, I do not understand two things:
1) When I switch from "manual" to "stabilized" mode all of my servos jump some 15 degrees CW.
2) When I roll (or pitch) the IMU in stabilized mode and leave it rolled (or pitched) servos react with just a proportional counter action. I expected that the integration part of the PID controller would - with a bit of delay - drive the servos to their maximum deflection.
Any suggestions?
Juergen
Replies
I also only see a proportional counter action.
I think this is how it is supposed to work though. You would not the servos to go to their maximum deflection. This can be set in the PID gain values though. If it went to maximum deflection than the airframe would correct way too fast(depending on speed?). Could result in overcorrection.
Does the AP change the amount of deflection based on speed?... It seems like it should, and that we should be able to enter minimum PID values and minimum speed, as well as the maximum. That way the AP could adjust the amount of deflection based on how fast your going(faster speed would use less deflection). This would result in the time it takes the AP to correct being the same whether you are 25mph or 140mph. I wonder if that is already implemented?
1) That probably means that you don't have the APM board level in your aircraft or you didn't hold it level during calibration at bootup
2) The deflection may seem small, but it's all that's required in flight. It will never drive the servos to maximum deflection, nor would you want it to.