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Bug #21949

Control Surfaces' Pitch/Yaw/Roll Direction Wrong Depending on Rotation of the Surface

Added by Vycma over 5 years ago. Updated over 3 years ago.

Status:
Updated
Severity:
Low
Assignee:
victorr
Category:
Controls and UI
Target version:
-
Start date:
04/22/2019
% Done:

10%

Version:
1.8.0
Platform:
Windows
Expansion:
Breaking Ground, Core Game, Making History
Language:
English (US)
Mod Related:
No
Votes:
Arrow u r green
Arrow d r red

Description

Depending on the rotation of a control surface the pitch/yaw/roll (deployment) direction is opposite to a given control input. It is counter to the direction that should be chosen, based on the relative longitudinal position of the control surface to the center of mass of a craft.

Minor deviations in rotation (~10°) are enough to invert the actual control input.

Issue exists at least since version 1.1.0 (see related issues).

Limitation of Workarounds (Inverted Deployment / Authority Limiters)

For simple toggled deployment the issue can be resolved by setting "Deploy Direction" to "Inverted". This setting however does not effect flight control inputs.

Setting a negative Authority Limiter value as a workaround for flight controls does not resolve the issue, since only pitch/yaw can be adjusted this way to give the desired direction, however previously correct roll behaviour is then simultaneously incorrectly inverted.

Reproduction Steps

1. Attach swept wing sections to a fuselage.

2. Attach control surfaces to the wing sections.

3. Rotate every other control surface in the XY-plane (even 10° should be enough).

4. Launch the craft and pitch.

5. Observation: Some control surfaces in front and behind the CoM will pitch correctly even when rotated. Closer to the CoM the rotated surfaces will invert the input.

Related Issues

https://bugs.kerbalspaceprogram.com/issues/9407
https://bugs.kerbalspaceprogram.com/issues/9460
https://bugs.kerbalspaceprogram.com/issues/20847

General Layout.jpg (269 KB) General Layout.jpg Test craft. Center of mass is marked with the plate cross on the fuselage. Vycma, 04/22/2019 04:50 PM
Pitch Up Input.jpg (283 KB) Pitch Up Input.jpg Pitch up input via keyboard controls. Approximately half of the rotated control surfaces have the input inverted, even when only slightly rotated. Vycma, 04/22/2019 04:51 PM
Test 21949.craft (432 KB) Test 21949.craft victorr, 10/29/2019 09:13 PM
Control surface deploy angle after rotated.png (1.66 MB) Control surface deploy angle after rotated.png victorr, 10/29/2019 09:14 PM
Control surface deploy angle after rotated more wings.png (1.66 MB) Control surface deploy angle after rotated more wings.png victorr, 10/29/2019 09:14 PM
Bug21949.craft (208 KB) Bug21949.craft Bug reproduction craft in original post Vycma, 10/30/2019 10:20 AM
Test 21949 alt.craft (420 KB) Test 21949 alt.craft Test21949 craft with altered wings Vycma, 10/30/2019 10:20 AM
Test 21949 alt.jpg (285 KB) Test 21949 alt.jpg Test21949 craft with altered wings Vycma, 10/30/2019 10:20 AM
Test 21949 swept.craft (433 KB) Test 21949 swept.craft Test21949 craft with swept wings Vycma, 10/30/2019 10:20 AM
Test 21949 swept.jpg (298 KB) Test 21949 swept.jpg Test21949 craft with swept wings Vycma, 10/30/2019 10:20 AM
Test 21949 mod.craft (221 KB) Test 21949 mod.craft Test21949 craft with perpendicularly rotated control surfaces Vycma, 10/30/2019 12:02 PM
Test 21949 mod.jpg (274 KB) Test 21949 mod.jpg Test21949 craft with perpendicularly rotated control surfaces Vycma, 10/30/2019 12:02 PM
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History

#1 Updated by Vycma over 5 years ago

  • Description updated (diff)

#2 Updated by Vycma over 5 years ago

  • Description updated (diff)

Correction: The minimum angle of rotation compared to a reference control surface seems to be ~10° (not 7.5°).

#3 Updated by Vycma over 5 years ago

Update:

Issue still exists in 1.7.2

#4 Updated by Vycma over 5 years ago

  • Subject changed from Control surfaces' Pitch/Yaw/Roll direction wrong depending on rotation of the surface to Control Surfaces' Pitch/Yaw/Roll Direction Wrong Depending on Rotation of the Surface
  • Version changed from 1.7.0 to 1.7.2
  • Expansion Breaking Ground added

#5 Updated by Vycma over 5 years ago

  • Version changed from 1.7.2 to 1.7.3

Update:

Issue still exists in 1.7.3

#6 Updated by Vycma about 5 years ago

  • Version changed from 1.7.3 to 1.8.0

Update:

Issue still exists in 1.8.1

#7 Updated by victorr about 5 years ago

  • Assignee set to victorr

#8 Updated by victorr about 5 years ago

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50046

Have not been able to reproduce in 1.8.1. I'm attaching a test ship with lots of tilted control surfaces and the CoM way back. All control surfaces move in unison and with the expected behavior. We'd like some more input.

#9 Updated by Vycma about 5 years ago

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50062

Thank you for your post, victorr. The key to reproduce this bug is to rotate the wings, so that they are no longer perpendicular to the main fuselage. Once they are swept, some of the slightly differently rotated surfaces will pitch opposite to adjacent ones, especially closer to the CoM.

I attached two modifications of your test craft and my own test craft, where I hope it is more apparent, what the problem is.

#10 Updated by Vycma about 5 years ago

50064

I hope the following reproduction steps are a bit clearer:

1. Attach wing sections to a fuselage.

2. Attach control surfaces to the wing sections.

3. Rotate the wing sections in the XY-plane backwards.

4. Rotate every other control surface in the XY-plane so that it is again approximately perpendicular to the fuselage.

5. Launch the craft and pitch.

Note:
The problem also appears if you increase (not decrease) the angle of every other control surface in step 4, however it seems to be less pronounced in this case. Perpendicularity is also not strictly necessary, as stated, 10° deviation is enough.

I attached another modification of victorr's test craft to point out those steps.

#11 Updated by Vycma almost 5 years ago

Update:

Issue still exists in 1.9.0

#12 Updated by Vycma over 4 years ago

Update:

Issue still exists in 1.10.0

#13 Updated by Vycma over 4 years ago

  • Status changed from Need More Info to Updated
  • % Done changed from 0 to 10

#14 Updated by Vycma about 4 years ago

Update:

Issue still exists in 1.11.0

#15 Updated by Vycma almost 4 years ago

Update:

Issue still exists in 1.11.1

#16 Updated by Vycma over 3 years ago

Update:

Issue still exists in 1.12.0

#17 Updated by Vycma over 3 years ago

Update:

Issue still exists in 1.12.2

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