Compute velocity errors when using an effort command interface

[tingelst]

This PR is in reference to the discussion in issue #673 (comment). The changes in 8e6697b introduced a bug in that the velocity error terms was not computed when using an effort command interface, resulting in a wobbly/jerky motion. This PR fixes this issue.

[bmagyar]

Do you have a good idea for adding a test for this? To avoid making this mistake in the future

[codecov-commenter]

Codecov Report

Merging #679 (2e0da5d) into master (e7f9962) will increase coverage by 0.75%.
The diff coverage is 34.91%.

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@@            Coverage Diff             @@
##           master     #679      +/-   ##
==========================================
+ Coverage   35.78%   36.53%   +0.75%     
==========================================
  Files         189        7     -182     
  Lines       17570      676   -16894     
  Branches    11592      357   -11235     
==========================================
- Hits         6287      247    -6040     
+ Misses        994      134     -860     
+ Partials    10289      295    -9994     

Flag	Coverage Δ
unittests	36.53% <34.91%> (+0.75%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ontroller/test/test_load_diff_drive_controller.cpp	11.11% <0.00%> (ø)
diff_drive_controller/src/odometry.cpp	42.16% <11.11%> (ø)
diff_drive_controller/src/speed_limiter.cpp	46.55% <11.11%> (ø)
...ive_controller/test/test_diff_drive_controller.cpp	17.62% <12.08%> (ø)
...iff_drive_controller/src/diff_drive_controller.cpp	47.09% <46.88%> (ø)
...de/diff_drive_controller/diff_drive_controller.hpp	100.00% <100.00%> (ø)
...troller/include/diff_drive_controller/odometry.hpp	100.00% <100.00%> (ø)

... and 189 files with indirect coverage changes

[christophfroehlich]

I think this is fine. But I'm not sure if #491 really introduced this, the velocity error wasn't calculated before with effort command interface?

[tingelst]

The velocity error was calculated before, but it was done directly in the computeCommand as seen here.

[christophfroehlich]

The velocity error was calculated before, but it was done directly in the computeCommand as seen here.

I see, sorry. I thought I removed the redundant difference calculation only, but hadn't had the effort interface in mind.
Let's add a test for that! Effort controller tests are active again with the jtc-features branch, see #607

[christophfroehlich]

I've written a test and made the PR #690 against jtc-features branch, where the effort tests are active already. It failed before I cherry-picked the commit from this PR. Let the maintainers decide if we merge the test directly to master or wait for jtc-features to be merged.

[mergify]

This pull request is in conflict. Could you fix it @tingelst?

[christophfroehlich]

@destogl this is already included in #705 (I squashed the changes, this is why it shows new commits but no changes)

[destogl]

OK, I'll then close this, OK?