Fix warning messages in rootlocus_pid_designer unit tests by murrayrm · Pull Request #684 · python-control/python-control

murrayrm · 2021-12-27T07:01:16Z

This PR gets rid of warning messages introduced in PR #662:

Since rootlocus_pid_designer leaves either r or d disconnected, the interconnect function was generating warnings (76 of them...). This was fixed by using check_unused=False.
Calling rootlocus_pid_designer with plot=True seems to generate a Bode plot that is -1 and this creates a warning:

control/ctrlutil.py:75: RuntimeWarning: invalid value encountered in remainder
  dangle_desired = (dangle + period/2.) % period - period/2.

For now this latter problem is fixed by skipping this test.

@sawyerbfuller I'm not quite sure how to fix this error. If I try running the test by hand using

ct.rootlocus_pid_designer(syscont, input_signal='r', Kp0=0.01,
    derivative_in_feedback_path=True, gain='P')

then I get the following plot:

coveralls · 2021-12-27T07:10:15Z

Coverage decreased (-0.2%) to 93.383% when pulling 7cfa42a on murrayrm:fix_pid_designer_warnings into 8356044 on python-control:master.

murrayrm · 2021-12-31T16:35:33Z

Merging this for 0.9.1, but will create an issue to track the possible bug above.

murrayrm added 2 commits December 26, 2021 19:03

fix warning messages in pid_designer

674f6f6

skip rootlocus_pid_designer tests that are generating warnings

7cfa42a

murrayrm merged commit b78dcc4 into python-control:master Dec 31, 2021

murrayrm mentioned this pull request Dec 31, 2021

rootlocus_pid_designer plot looks strange + needs documentation #686

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