Copter travels too fast, minimum speed setting?

Hello all,

I’ve had great experiences thus far in finding help here. I’ve got another interesting problem - my hexacopter will not fly an AUTO mission at the speed I want it to.

I’m attempting to fly missions at 1.5-2m/s in order to capture high GSD with a FLIR thermal camera. I create surveys in MP, and set the flight speed at 1.8 (and sometimes 2m/s). I can see in the waypoint list in MP that Do_Change_Speed or something similar is called, and then it is reset to default after the mission is completed.

However, my flights seem to be flying closer to 3m/s? This is much to fast for what I’m doing and is resulting in inconsistent camera captures. I know I set my WPNAV_Speed to 3m/s as default - but I thought mission waypoints temporarily override this value?

Any input in getting my copter to fly slower would be appreciated. I have included a link to a relevant log file with this behavior. Thanks in advance!

WPNAV_SPEED is the setting you want to change. If you want a portion of the mission to fly slower you can indeed override it with a DO_CHANGE_SPEED command prior to the first point you want to fly slower. Avoid using DO_CHANGE_SPEED immediately following a takeoff waypoint, as it may be ignored (known issue).

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Thanks @Yuri_Rage!
I’ll attempt another flight with a Takeoff, Waypoint, and then a Survey (Grid) with a speed change. Hopefully that fixes my speed issue. If I could travel even down to 1m/s that would be awesome!

With a Copter, I don’t think there is a min speed. There is no physical need to keep airspeed above a minimum threshold as there is in a Plane.

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That did in fact work!
I planned a takeoff point, and a waypoint very close to it. I then planned a normal survey with a speed of 1m/s. It followed it!
Now I just need to tune my copter better to stop getting these weird dips in altitude during turn-arounds…

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Altitude issues are often barometer related. First step is to shield any open barometer with open cell foam or any open port (like the USB/SD slot) on a Cube-like controller with a bit of tape.

Then address any basic tuning issues.

Finally, have a look here for software compensation:
https://ardupilot.org/copter/docs/airspeed-estimation.html

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