There's strain relief in the servo wires, there's the Kysho pads on the corners, I've even tried putting the receiver itself onto the controller (same results on or off) to make absolutely certain there's not strain being put on the leads from the receiver..
Stabilize is just a dream , floats there. Switch to Alt-Hold. it'll be fine for a few seconds, then begins the sudden drop, then throttle up, wash-rinse repeat.
What MORE can be done to reduce vibrations on this F450?
Do you thing that a extrnal better baro can solve the problem? I found this external Baro, is it same as on APM2.5?
Issue resolved. This was not a vibration issue. While not perfect, the vibrations were previously reduced enough on this vehicle to be controllable. The cause of the current alt-hold issue was the limitations of precision with the APM1 barometer. The APM1 baro even when covered with opaque foam would, while sitting on a bench vary by a meter. ---Which not so coincidentally was the amount the vehicle would seemingly 'spontaneously drop' in altitude hold.
I replaced the APM1 with an APM2.5, using cloned the settings (correcting level and compass offsets), the new APM handled alt-hold with deviations on the order of centimeters --- which was the amount the baro altitude would vary while the vehicle was on the bench.
Z accels are NOT the problem here. The 'jumps' are less than 2-ish. If there's a tunable solution to this, please identify it. Right now the alt-hold wiki just has a warning that the tuning steps in there are for BEFORE the accel inertia work form 2.9.1 was added.
So this lack of a viable alt-hold is VERY VERY disturbing.
Stabilize, smooth as silk. Position hold, smooth too. once alt-hold gets control of the throttle, it's bouncing with about a 3 second period.
PLEASE, anyone who has a flamewheel f450, post PIDs for any system that has alt-hold working reliably (and logs as well please to confirm the settings)
2013-05-30 20-20 4.log
In my case it raises when Alt_Hold or Loiter modes are engaged.
Tried ALT_THR_P and I and any suggestion from the wiki without success.
If POS_HOLD is selected it holds position perfectly.
My copter does the same thing.
HAL hexa, 20A, 2827-34 750kv 11x4,5 Gemfan
I hover and as soon as I switch on alt hold the copter drops and tries to land.
Hi i have same problem as you, so i thing also that is THR_ALT or THR_ACCEL high gains or low D therms. I will play with setings and then tell you where to start.
I have sonar on my hexacopter but when i was flying over grass it was bumping extremely, so i swithed off and now is better but still jumping up and down in AltHold and Loiter. In Stabilize is perfect.
Also what telemetry radio are you using, if 900mhz, move it further away.
Usually when I see althold/loiter drop, it's a rate climb_rate issue, usually from an ESC issue or baro. Z accel is an issue if your PID for alt hold are too stiff.