I have a problem: Often, my aircraft flying Arduplane 3.3 on a Pixhawk with an airspeed sensor ignores my target airspeed. For example: I have planned a mission using the survey grid (v1) feature, setting target airspeed to 19 m/s and checking the box to “Use speed for this mission”. We are flying mapping missions. Flying this speed is critical, because we needed to take pictures at a very high frequency near the maximum rate of the camera. Throughout the mission, however, the plane flew much faster; target airspeed was around 22.4 m/s with the actual airspeed hovering around this value as it was a very gusty day.
This lead to a lot of pictures not being taken because the camera could not follow the shutter command.
Do you have any insight why the target airspeed was not set to the 19 m/s I commanded in the mission? I have checked the onboard logs, the command was included properly.
set ALT_CTRL_ALG to 1. That will tell the APM to control pitch and throttle with the non-airspeed algorithm. That is a bit simpler to tune.
or disable stall prevention… it always overrides airspeed target
Do you have logs or a param file?
There’s a couple things, if set incorrectly, could cause this. But, logs or a param file can help much more than guessing.
I had similar problem when the plane always flew at maximum airspeed and would not drop to target the airspeed.
In my case the min ground speed was set to 9000 (90m/s) instead of 900 (9m/s) so i would double check all your min max and target parameters to make sure nothing is out.
Thank you for all of your suggestions, I will try them out! I have uploaded a log file here:
dropbox.com/s/9oyr11vr7aiwx … m.BIN?dl=0
The minimum ground speed is not the problem; I have set it at 600 cm/s. The maximum airspeed is 30 m/s whereas the actual target was 22.5 m/s.
If you could have a look at the log file I would be very grateful.
I took a quick look and the airspeed for most of the ‘AUTO’ sections seems to average out at around 15m/s with just a short period in the 20’s. Can you clarify what you expected it to be?