[9.0.2] Wrong altitude controller defaults

[0crap]

The Wiki tells me I should get the following defaults for fixed-wing:

VELOCITY:
nav_fw_pos_z_p = 22
nav_fw_pos_z_i = 6
nav_fw_pos_z_d = 2
nav_fw_pos_z_ff = 25
nav_fw_alt_control_response = 45

What I get when flashing a MATEKF405 fc firmware v9.0.1 is:

• Airplane with a tail:

nav_fw_pos_z_p = 22
nav_fw_pos_z_i = 6
nav_fw_pos_z_d = 2
nav_fw_pos_z_ff = 30
nav_fw_alt_control_response = 45

• Airplane without a tail:

nav_fw_pos_z_p = 25
nav_fw_pos_z_i = 6
nav_fw_pos_z_d = 5
nav_fw_pos_z_ff = 30
nav_fw_alt_control_response = 45

[Jetrell]

It might have been that Marc wasn't sure which way to go with all the altitude controller default settings.
Due to there being platform type tunes, as well as the differences between both the Altitude Velocity and Position controllers.
That's why its help to have both methods and their tunes described in the Wiki.
If someone wants to use the Altitude Position controller. They would have to select it and manually change the gains to suit.

However, I never found the tune between a plane with or without a tail required to be different with the Altitude Velocity controller. Lowering of the ALT D and increasing of the ALT FF was more required with planes that have higher control surface throws.

If you haven't seen it. There is some more info on those gains here.

[sensei-hacker]

@b14ckyy do you have a comment on this?

[b14ckyy]

Delta wings without a tail never had issues with the too high values we had before. Also they have less pitch authority and are slower in pitch changes by nature, so I kept them slightly higher on D for earlier dampening on the altitude PIDs, same relationship as they where before. But its still lower than the too high firmware defaults.

with D=2 a delta wing tended to overshoot more after changes.

@0crap do you have issues with the preset values or is your question out of interest?

[0crap]

I'm upgrading from v7.1.2 to the latest, so I always readup on release notes and wiki.
I noticed, after applying defaults, it never matched with the wiki, which I find confusing.
Hence this ticket I created.

(Not tested yet on a fast Dolphin and slow AR.Wing 900, both airplane without a tail.)

[b14ckyy]

That is fair and exemplary :D

But yeah its generally difficult to handle everything since we have Firmware default values, then we have recommended values and then we have presets for different aircraft types.

@sensei-hacker Maybe in the future we should consider having after-setup profiles that could be applied as base tunes, without reset. Similar to the Betalight presets. Although that would need a big group for testing. Not sure if we have the necessary capacity for that.

[0crap]

For now it seems the default values are given some thought and seemingly correct, which makes this more a documentation issue.
I would suggest to add the values I reported in my opening post to the wiki, to make it consistent and call it a day?

[Jetrell]

Those Wiki defaults where written after development testing, months before the configurator defaults where changed to align with new tuning requirements.
To add the different airframe type default tunes there; would likely make it even more confusing.

The idea of that wiki, was to highlight the differences in the tuning required for altitude Velocity and Position controller operation. Those wiki values provide a conservative to moderate tune for both those controllers.

If the user wishes. It is up to them to tighten the nav_fw_pos_z_d or nav_fw_pos_z_ff to suit there requirements. As explained just before those tunes in the wiki.

[b14ckyy]

Moved to Discussion since its not a bug report.