Control: function addition for the phase criterion #26341
Conversation
I added a function to the TransferFunction class called phase_criterion(z) and has an input. This input can be a number that belongs to C and if it belongs to the Root Locus of the transfer function it returns True otherwise False. I think it's a good start for creating extensions over the Root Locus. Example: >>> system2 = TransferFunction((1), ((s**2+100*s+2600)*(s+25)*s), s) >>> z1 = 37.1+65.2*I >>> system2.phase_criterion(z1) True modified: sympy/physics/control/lti.py modified: sympy/physics/control/tests/test_lti.py
|
✅ Hi, I am the SymPy bot. I'm here to help you write a release notes entry. Please read the guide on how to write release notes. Your release notes are in good order. Here is what the release notes will look like:
This will be added to https://github.com/sympy/sympy/wiki/Release-Notes-for-1.13. Click here to see the pull request description that was parsed. |
|
Can you point to something that explains what the phase criteria is? This may be a useful addition, but you'll need to make it work with fully symbolic transfer functions. |
|
Yes, it was a mistake not to analyze the phase criterion further. Τhe sum of the angles from the open-loop zeros to the point minus the angles from the open-loop poles to the point has to be equal to π. The point mentioned in the above wikipedia extension is the number we give to the function. If this criterion is true then this point is rootlocus' part. |
|
I will correct the name and the errors that were thrown out. And I'll commit again. |
I added a function to the TransferFunction class called phase_condition(z) and has an input. This input can be a number that belongs to C and if it belongs to the Root Locus of the transfer function phase_condition returns True otherwise False. I think it's a good start for creating extensions over the Root Locus. Example: >>> system2 = TransferFunction((1), ((s**2+100*s+2600)*(s+25)*s), s) >>> z1 = 37.1+65.2*I >>> system2.phase_condition(z1) True modified: sympy/physics/control/lti.py modified: sympy/physics/control/tests/test_lti.py Note: This is the same commit with previous but with correct name (condition, not criterion) Reference: https://en.wikipedia.org/wiki/Root_locus_analysis
This code quality error occur: AssertionError: File contains trailing whitespace: /home/runner/work/sympy/sympy/sympy/physics/control/lti.py
Modified the code to pass the code-quality test
When I started writing this function, I wanted to make it as symbolic as possible. When I say symbolic, I mean using only the sympy tools. Could you refer me or give me more information about what you are thinking about? |
|
You can start by having no numbers in your unit tests, only symbols. |
Notes: (I forgot to mention that the relation should be equal to the odd multiple of pi). I modified the function to work with symbolic input numbers. Some constraints arose: 1. I was able to do the implementation for the first 8 odd multiples. 2. The processing of the symbolic characters needs a little more work.
Substrate the greek letter π with pi.
There was an error about the parentheses in the test_phase_condition.
I modified the function to be able to process symbolic inputs. But it still needs some corrections. |
Brief description of what is fixed or changed
I added a function to the TransferFunction class called phase_condition and has an input.
This input can be a number that belongs to C,
if it belongs to the Root Locus of the transfer function it returns True otherwise False.
Other comments
Release Notes
Reference
Root Locus Analysis