Reintroduce slow down when landing manually

[MaEtUgR]

Test data / coverage
Implementation is in our public release and tested a lot. The port is untested (not even SITL).

Describe problem solved by the proposed pull request
Same as #11487. I'm porting our solution here for comparison. Discussing with @bresch about how to proceed with the altitude slowdown/smoothing.

Additional context
#10659
There was a global position controller wide slow down constraint when flying downwards and getting close to the ground before the flight task architecture. For auto flight it was added again but not for manual flight yet.

[bresch]

This is really similar to https://github.com/PX4/Firmware/blob/f229444722132a2e71d92d425597faaadcb480c4/src/lib/FlightTasks/tasks/AutoMapper/FlightTaskAutoMapper.cpp#L149-L162
Which one is best? Should we use the same code for both?

[bresch]

I tested this branch with the SmoothVel FlightTask and worked as expected:
https://logs.px4.io/plot_app?log=27b74a04-05a6-4489-936c-48ce2c2f4acc

@MaEtUgR The thing I might still want is to limit the upward velocity the same way.

[MaEtUgR]

Devcall: @bresch tested and it seems viable for him. I need to add the slow, smooth takeoff the same way and then we can use this solution as first step. Improved constraint handling which was the idea in #11487 can be added on top.

[MaEtUgR]

I already ported the same thing to upstream some time ago 😄 : #11080

[MaEtUgR]

@bresch I rebased on master and added the slow start upwards when close to ground part. I did a quick successful SITL test. Could you do your checks as well?

[MaEtUgR]

[bresch]

@MaEtUgR Cool, I'll try that tomorrow if possible.

[bresch]

I made a few SITL tests and works as expected, I think it's ready to go for the flight test team.

[bresch]

SITL result with Smooth position control (Velocity) sub mode:

[bresch]

@PX4/testflights Can you test that on a quadcopter please?
We need to test both Smooth position control (velocity) and Smooth position control of MPC_POS_MODE.
Please set MPC_ACC_DOWN_MAX and MPC_ACC_UP_MAX to 3 m/s^2 for nicer results

Thanks!

[jorge789]

Parameters tested on Pixhawk v4Pro: Smooth position control of MPC_POS_MODE; 3m/s/s for MPC_ACC_DOWN_MAX and 3m/s/s for MPC_ACC_UP_MAX, no issues were noted. Good flight in general.

https://review.px4.io/plot_app?log=bc7f38cc-da4b-46ad-bc7d-c33837659a90

Parameters tested on Pixracer v4: Smooth position control of MPC_POS_MODE; 3m/s/s for MPC_ACC_DOWN_MAX and 3m/s/s for MPC_ACC_UP_MAX, no issues were noted. Good flight in general.

https://review.px4.io/plot_app?log=bc7f38cc-da4b-46ad-bc7d-c33837659a90

Parameters tested on Pixracer v4: Smooth position control (velocity) of MPC_POS_MODE; 3m/s/s for MPC_ACC_DOWN_MAX and 3m/s/s for MPC_ACC_UP_MAX, no issues were noted. Good flight in general.

https://review.px4.io/plot_app?log=2aff3e8a-cdcc-4075-8445-39b217efc403

[LorenzMeier]

Thanks for testing!

[Junkim3DR]

Tested on Pixhawk 4 v5, parameter tested were:

• Smooth position control for MPC_POS_MODE.
• 3m/s/s for MPC_ACC_DOWN_MAX.
• 3m/s/s for MPC_ACC_UP_MAX.

Issues Noted:

• Parameters couldn't be saved while PR was loaded (Lost connection a few seconds after changing parameters). Solution: Load Master, change parameters and then load PR.
• Not disarming automatically nor manually, kill switch not working.

https://review.px4.io/plot_app?log=43aece45-c1ea-49dd-a22d-5ff0d577bb6a

[MaEtUgR]

@Junkim3DR One moment. This pr does not change anything with the parameters you listed. Ar you completely sure that it was the cause of your problems? Were there any follow-ups I missed? Does this still happen on master after the pr was merged?