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Set up 'config' module that allows user-defined defaults
 * Will eventually allow MATLAB defaults if user imports control.matlab first New module 'canonical' for implementing canconical forms. Needed for trajectory generation module (coming soon).
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‎ChangeLog‎

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2012-11-10 Richard Murray <murray@altura.local>
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* src/canonical.py: new module implementing conversions to selected
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canonical forms: canonical_form(), reachable_form() implemented
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* src/lti.py (issiso): new function to quickly check if a system is
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single input, single output or not
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2012-11-04 Richard Murray <murray@altura.local>
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* src/__init__.py: added action item to separate out matlab module
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functionality (eventually)
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* src/matlab.py: added code for setting up MATLAB defaults if matlab
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submodule is imported instead of main (control) module. See
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comments in __init.py__ for what needs to be done to implement.
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* src/freqplot.py (bode_plot): moved default values of plotting
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options to config module to allow easier use override
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* src/config.py: new module to help set package defaults
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* src/xferfcn.py (_convertToTransferFunction): removed extraneous
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print statements if slycot is not installed
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* src/statesp.py (StateSpace.__str__): fixed error in printing
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timebase when dt is None (python 3)
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---- control-0.6c released -----
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2012-11-03 Richard Murray <murray@altura.local>

‎src/__init__.py‎

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from control.dtime import sample_system
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from control.freqplot import bode_plot, nyquist_plot, gangof4_plot
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from control.freqplot import bode, nyquist, gangof4
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from control.lti import timebase, timebaseEqual, isdtime, isctime
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from control.lti import issiso, timebase, timebaseEqual, isdtime, isctime
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from control.margins import stability_margins, phase_crossover_frequencies
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from control.mateqn import lyap, dlyap, care, dare
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from control.modelsimp import hsvd, modred, balred, era, markov
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from control.xferfcn import TransferFunction
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from control.ctrlutil import unwrap, issys
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from control.frdata import FRD
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from control.canonical import canonical_form, reachable_form
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# Exceptions
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from exception import *
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# Import some of the more common (and benign) MATLAB shortcuts
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# By default, don't import conflicting commands here
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#! TODO (RMM, 4 Nov 2012): remove MATLAB dependencies from __init__.py
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#!
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#! Eventually, all functionality should be in modules *other* than matlab.
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#! This will allow inclusion of the matlab module to set up a different set
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#! of defaults from the main package. At that point, the matlab module will
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#! allow provide compatibility with MATLAB but no package functionality.
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#!
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from control.matlab import ss, tf, ss2tf, tf2ss, drss
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from control.matlab import pole, zero, evalfr, freqresp, dcgain
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from control.matlab import nichols, rlocus, margin

‎src/canonical.py‎

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# canonical.py - functions for converting systems to canonical forms
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# RMM, 10 Nov 2012
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import control
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from numpy import zeros, shape, poly
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from numpy.linalg import inv
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def canonical_form(sys, form):
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"""Convert a system into canonical form
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Parameters
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----------
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xsys : StateSpace object
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System to be transformed, with state 'x'
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form : String
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Canonical form for transformation. Chosen from:
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* 'reachable' - reachable canonical form
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* 'observable' - observable canonical form
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* 'modal' - modal canonical form [not implemented]
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Outputs
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-------
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zsys : StateSpace object
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System in desired canonical form, with state 'z'
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T : matrix
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Coordinate transformation matrix, z = T*x
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"""
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# Call the appropriate tranformation function
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if form == 'reachable':
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return reachable_form(xsys)
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else:
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raise control.ControlNotImplemented(
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"Canonical form '%s' not yet implemented" % form)
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# Reachable canonical form
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def reachable_form(xsys):
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# Check to make sure we have a SISO system
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if not control.issiso(xsys):
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raise control.ControlNotImplemented(
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"Canonical forms for MIMO systems not yet supported")
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# Create a new system, starting with a copy of the old one
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zsys = control.StateSpace(xsys)
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# Generate the system matrices for the desired canonical form
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zsys.B = zeros(shape(xsys.B)); zsys.B[0, 0] = 1;
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zsys.A = zeros(shape(xsys.A))
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Apoly = poly(xsys.A) # characteristic polynomial
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for i in range(0, xsys.states):
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zsys.A[0, i] = -Apoly[i+1] / Apoly[0]
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if (i+1 < xsys.states): zsys.A[i+1, i] = 1
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# Compute the reachability matrices for each set of states
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Wrx = control.ctrb(xsys.A, xsys.B)
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Wrz = control.ctrb(zsys.A, zsys.B)
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# Transformation from one form to another
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Tzx = Wrz * inv(Wrx)
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# Finally, compute the output matrix
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zsys.C = xsys.C * inv(Tzx)
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return zsys, Tzx

‎src/config.py‎

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# config.py - package defaults
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# RMM, 4 Nov 2012
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#
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# This file contains default values and utility functions for setting
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# variables that control the behavior of the control package.
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# Eventually it will be possible to read and write configuration
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# files. For now, you can just choose between MATLAB and FBS default
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# values.
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# Bode plot defaults
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bode_dB = False # Bode plot magnitude units
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bode_deg = True # Bode Plot phase units
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bode_Hz = False # Bode plot frequency units
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# Set defaults to match MATLAB
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def use_matlab_defaults():
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# Bode plot defaults
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global bode_dB; bode_dB = True
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global bode_deg; bode_deg = True
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global bode_Hz; bode_Hz = True
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# Set defaults to match FBS (Astrom and Murray)
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def use_fbs_defaults():
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# Bode plot defaults
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global bode_dB; bode_dB = False
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global bode_deg; bode_deg = True
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global bode_Hz; bode_Hz = True

‎src/freqplot.py‎

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#
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# Bode plot
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def bode_plot(syslist, omega=None, dB=False, Hz=False, deg=True,
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def bode_plot(syslist, omega=None, dB=None, Hz=None, deg=None,
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Plot=True, *args, **kwargs):
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"""Bode plot for a system
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>>> sys = ss("1. -2; 3. -4", "5.; 7", "6. 8", "9.")
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>>> mag, phase, omega = bode(sys)
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"""
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# Set default values for options
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import control.config
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if (dB is None): dB = control.config.bode_dB
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if (deg is None): deg = control.config.bode_deg
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if (Hz is None): Hz = control.config.bode_Hz
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# If argument was a singleton, turn it into a list
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if (not getattr(syslist, '__iter__', False)):
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syslist = (syslist,)

‎src/matlab.py‎

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from scipy.signal import zpk2ss, ss2zpk, tf2zpk, zpk2tf
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from numpy import linspace, logspace
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# If configuration is not yet set, import and use MATLAB defaults
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#! NOTE (RMM, 4 Nov 2012): MATLAB default initialization commented out for now
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#!
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#! This code will eventually be used so that import control.matlab will
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#! automatically use MATLAB defaults, while import control will use package
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#! defaults. In order for that to work, we need to make sure that
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#! __init__.py does not include anything in the MATLAB module.
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# import sys
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# if not ('control.config' in sys.modules):
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# import control.config
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# control.config.use_matlab()
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# Control system library
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import control.ctrlutil as ctrlutil
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import control.freqplot as freqplot

‎src/statesp.py‎

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# Here we're going to convert inputs to matrices, if the user gave a
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# non-matrix type.
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#! TODO: [A, B, C, D] = map(matrix, [A, B, C, D])?
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matrices = [A, B, C, D]
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for i in range(len(matrices)):
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# Convert to matrix first, if necessary.
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str += "B = " + self.B.__str__() + "\n\n"
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str += "C = " + self.C.__str__() + "\n\n"
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str += "D = " + self.D.__str__() + "\n"
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#! TODO: replace with standard calls to lti functions
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if (type(self.dt) == bool and self.dt == True):
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str += "\ndt unspecified\n"
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elif (self.dt > 0):
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elif (not (self.dt is None) and type(self.dt) != bool and self.dt > 0):
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str += "\ndt = " + self.dt.__str__() + "\n"
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return str
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‎src/xferfcn.py‎

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mimo = self.inputs > 1 or self.outputs > 1
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if (var == None):
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#! TODO: replace with standard calls to lti functions
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var = 's' if self.dt == None or self.dt == 0 else 'z'
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outstr = ""
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# See if this is a discrete time system with specific sampling time
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if (not (self.dt is None) and type(self.dt) != bool and self.dt > 0):
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#! TODO: replace with standard calls to lti functions
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outstr += "\ndt = " + self.dt.__str__() + "\n"
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return outstr
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lti_sys = lti(sys.A, sys.B, sys.C, sys.D)
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num = squeeze(lti_sys.num)
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den = squeeze(lti_sys.den)
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print(num)
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print(den)
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# print(num)
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# print(den)
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return TransferFunction(num, den, sys.dt)
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