Fix angular locked axes in gyroscopic torque computation #485
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Jondolf
added
C-Bug
Jondolf
pushed a commit
that referenced
this pull request
Aug 19, 2024
# Objective I think that #485 wasn't quite the right fix for #474 - applying locked axes to an inertia tensor zeros out one or more of its rows, making the matrix singular - taking the inverse then results in a matrix that's all NaNs, making the delta_ang_vel also all NaNs, which causes the angular momentum to be unaffected by anything that timestep (including applied torques!). The problem with the status quo ante seems to be that a similar thing happened - rather than trying to invert the (singular) locked inverse inertia, the calculated Jacobian was (near-)singular in a lot of cases when axes were locked, and depending on round-off errors you'd either get NaNs or just an outright cancellation of the angular velocity ## Solution Calculating the delta-ω from gyroscopic effects with an unconstrained inertia matrix and *then* applying the locked axes to that angular velocity increment should be more reliable, and should avoid undesirable NaN values showing up
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Objective
Fixes #474.
The angular locked axes are applied to the inertia instead of the inverse inertia in gyroscopic torque computations introduced in #420, causing incorrect behavior.
Solution
Apply the locked axes correctly.