Merge pull request #980 from murrayrm/phaseplots_01Jan2024

Reimplementation of 2D phase plots

control/__init__.py

@@ -63,6 +63,7 @@
 * :mod:`~control.flatsys`: Differentially flat systems
 * :mod:`~control.matlab`: MATLAB compatibility module
 * :mod:`~control.optimal`: Optimization-based control
+* :mod:`~control.phaseplot`: 2D phase plane diagrams
 
 """
 
@@ -103,6 +104,10 @@
 from .passivity import *
 from .sysnorm import *
 
+# Allow access to phase_plane functions as ct.phaseplot.fcn or ct.pp.fcn
+from . import phaseplot
+from . import phaseplot as pp
+
 # Exceptions
 from .exception import *
 

control/config.py

@@ -152,6 +152,9 @@ def reset_defaults():
     from .timeplot import _timeplot_defaults
     defaults.update(_timeplot_defaults)
 
+    from .phaseplot import _phaseplot_defaults
+    defaults.update(_phaseplot_defaults)
+
 
 def _get_param(module, param, argval=None, defval=None, pop=False, last=False):
     """Return the default value for a configuration option.

control/flatsys/__init__.py

@@ -35,8 +35,10 @@
 # Author: Richard M. Murray
 # Date: 1 Jul 2019
 
-r"""The :mod:`control.flatsys` package contains a set of classes and functions
-that can be used to compute trajectories for differentially flat systems.
+r"""Differentially flat systems sub-package.
+
+The :mod:`control.flatsys` sub-package contains a set of classes and
+functions to compute trajectories for differentially flat systems.
 
 A differentially flat system is defined by creating an object using the
 :class:`~control.flatsys.FlatSystem` class, which has member functions for

control/freqplot.py

@@ -1070,7 +1070,7 @@ def gen_zero_centered_series(val_min, val_max, period):
 _nyquist_defaults = {
     'nyquist.primary_style': ['-', '-.'],       # style for primary curve
     'nyquist.mirror_style': ['--', ':'],        # style for mirror curve
-    'nyquist.arrows': 2,                        # number of arrors around curve
+    'nyquist.arrows': 2,                        # number of arrows around curve
     'nyquist.arrow_size': 8,                    # pixel size for arrows
     'nyquist.encirclement_threshold': 0.05,     # warning threshold
     'nyquist.indent_radius': 1e-4,              # indentation radius