Set_position_target_local_ned velocity is ignored

I’m sending SET_POSITION_TARGET_LOCAL_NED messages to my copter and I can confirm that they are being received by watching the MAVLink Inspector in QGroundControl. I’ve also confirmed that the message is the correct format and is resulting in calls to copter.mode_guided.set_velocity in GCS_Mavlink.cpp by adding debug send_text lines immediately before hand. However, still the copter does not move, it just stays in an armed state with motors at minimum throttle. I can continue to insert send_text lines in the firmware to track down why the copter.mode_guided.set_velocity method calls aren’t resulting in drone movement, but I thought you guys might have some ideas about where I could look or parameters to double check.

The drone is in GUIDED mode.
All arming checks are off.


Unless you want to test something unsafe, arming check SHOULD NEVER BE OFF !!!

Otherwise, I assume that you didn’t takeoff, and that is your issue. In order to use set position command, you need to takeoff first ! In guided, you have can use the takeoff command.

Thank you that was at least part of my issue. I had arming checks disabled because my drone is in a physical restraint harness and I was having lots of trouble with arming checks preventing arming even when they shouldn’t have been due to my unusual setup. Either way I am re-enabling most of them now.

Were you in guided mode?

Yes. I was definitely in guided mode.

I suggest sending through a takeoff command; if the vehicle is landed we
essentially do nothing. Simply requesting an upwards velocity is not

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I tried takeoff 0.1 and takeoff 1, but only 1m altitude did anything. I have the drone in a harness so I don’t really have 1m to maneuver. Is there a way to take off with less than 1m altitude, it seems there is a minimum set somewhere? Or maybe I should “takeoff” in stabalized mode and then switch to guided?

Hi @dwiel,
Did you find any progress?

I don’t remember what finally did it. I ended up heavily modifying guided mode to suit my somewhat unusual needs.