after replacing a faulty GPS with a new one my first flight was very amazing. AltHold and PosHold work as expected (with a high precision out of the box - wow).
Today I went to another fly with ground station (APM Planner) for RTL and mission tests. But for no reason AltHold did not work anymore.
If I (perfectly) hover the quad and switch from Stab to AltHold the quad stays at this altitude, but did not respond to any throttle input. For my understanding the quad should climb (2.5m/s) by rising throttle above 60% and descend (2.5m/s) by lowering throttle below 40%. This works for my first flight but not on second or third one.
If I climb/descend slowly (throttle within 40%-60%) and switch to AltHold the current altitude should be hold. This works for my first flight but not on second or third one. Instead of holding altitude it keeps climbing/descending for ever.
If I fly forward/backward/sideward with AltHold the quad starts ascending/descending after some time. Nothing can stop this except switch to Stab mode.
I did not change something on my quad or on APM configs and Im using an APM Kit, Turnigy 9X as radio, APM Copter 3.2.1 and 4s lips. My quad is hovering at 48-49% of throttle (nearly perfect at 50%). All config values are default. On first flight it was bit warmer and maybe a lower humidity, but could this be a reason?
After second and third flight I made an additional radio calibration. All seems to be fine, but one question: after calibration the GUI shows me for RC3 input (throttle) a center value of 1059 (min: 1058 max 1894). Is this a proper value? (seems to be a bit odd)
Whats wrong with my AltHold mode (or APM)?
Best Regards,
otbe
Observation on second flight in AltHold mode:
The ground station shows me an altitude of ~10m and a climb rate of -0.1 to +0.1 while using AltHold. But for any reason the quad climbs at high rate and the ground station did not recognized it.
Logging of IMU is disabled by default (how to enable?)
But why this works for my first flight? With same props, same battery pack …
Correct me if I got it wrong, but in your picture DAlt (desired alt) starts decreasing at x~=5000 with no throttle change. This should not happen, shouldnt it?
[quote=“otbe0”]
Correct me if I got it wrong, but in your picture DAlt (desired alt) starts decreasing at x~=5000 with no throttle change. This should not happen, shouldnt it?[/quote]
This is from my third flight. DAlt ist decreasing with no throttle change. In real life the quad was descending much faster than it looks like in this picture and much closer to the ground. Only switching to stab mode allowed me to safe my quad.
Look at x=9000:
DAlt is increasing, BarAlt too. But z vibrations are “constant” and throttle input decreased to zero at x=9900 and no response from APM. Only switching modes stops infinite climbing of my quad.
Look at my picture:
DAlt is increasing, BarAlt too. But z vibrations are “constant” and throttle input decreased to zero at x=9900 and no response from APM. Only switching modes stops infinite climbing of my quad.
It seems that APM recognize my throttle input (~50%) as a request to climb
In other words: the APM does not change ThrOut at all.
If I hover perfectly and switch to AltHold it stays at current altitude. If I fly forward/backward/sideward it starts descending and no correction happens.
If I switch to AltHold with a small rate of climbing, the APM does not tries to stop it. It will climb forever (ascending or descending).
But: If i rise to 50m, cutoff throttle (decrease to 20%) and switch from Stab to AltHold the APM tries to stop my quad falling. It does not work perfectly, but you can here props spin up a lot.
These parameters are accessible via the Extended Tuning “page”, lower part about “Throttle Rate”, “Throttle Accel” and “Altitude Hold” as I understand it. My problem is that they are randomly set to 0 unintentionally and saved to the FC when saving another change I did.
That’s it. Or maybe this could be the solution. I will give it a try tomorrow. Thank you.
If I change some settings it causes in almost every case a invalid state of some other params.
After some time waiting it works as expected. GCS seems to be buggy
(how to enable?)