Revision: 300
http://sourceforge.net/p/python-control/code/300
Author: repa
Date: 2014-06-11 05:00:09 +0000 (Wed, 11 Jun 2014)
Log Message:
-----------
added a more complex test case to the matlab code. This test case was
actually hit upon by one of my students, the control/numpy combination
resulted in phase margin detected near omega=0
Modified Paths:
--------------
trunk/tests/matlab_test.py
Modified: trunk/tests/matlab_test.py
===================================================================
--- trunk/tests/matlab_test.py 2014-05-23 12:41:47 UTC (rev 299)
+++ trunk/tests/matlab_test.py 2014-06-11 05:00:09 UTC (rev 300)
@@ -534,7 +534,62 @@
-0.304617775734327 0.075182622718853"""), sysd.B)
+ def testCombi01(self):
+ # test from a "real" case, combines tf, ss, connect and margin
+ # this is a type 2 system, with phase starting at -180. The
+ # margin command should remove the solution for w = nearly zero
+ # Example is a concocted two-body satellite with flexible link
+ Jb = 400;
+ Jp = 1000;
+ k = 10;
+ b = 5;
+
+ # can now define an "s" variable, to make TF's
+ s = tf([1, 0], [1]);
+ hb1 = 1/(Jb*s);
+ hb2 = 1/s;
+ hp1 = 1/(Jp*s);
+ hp2 = 1/s;
+
+ # convert to ss and append
+ sat0 = append(ss(hb1), ss(hb2), k, b, ss(hp1), ss(hp2));
+
+ # connection of the elements with connect call
+ Q = [[1, -3, -4], # link moment (spring, damper), feedback to body
+ [2, 1, 0], # link integrator to body velocity
+ [3, 2, -6], # spring input, th_b - th_p
+ [4, 1, -5], # damper input
+ [5, 3, 4], # link moment, acting on payload
+ [6, 5, 0]]
+ inputs = [1];
+ outputs = [1, 2, 5, 6];
+ sat1 = connect(sat0, Q, inputs, outputs);
+
+ # matched notch filter
+ wno = 0.19
+ z1 = 0.05
+ z2 = 0.7
+ Hno = (1+2*z1/wno*s+s**2/wno**2)/(1+2*z2/wno*s+s**2/wno**2)
+
+ # the controller, Kp = 1 for now
+ Kp = 1.64
+ tau_PD = 50.
+ Hc = (1 + tau_PD*s)*Kp
+
+ # start with the basic satellite model sat1, and get the
+ # payload attitude response
+ Hp = tf(sp.matrix([0, 0, 0, 1])*sat1)
+
+ # total open loop
+ Hol = Hc*Hno*Hp
+
+ gm, pm, wg, wp = margin(Hol)
+ self.assertAlmostEqual(gm, 3.32065569155)
+ self.assertAlmostEqual(pm, 46.9740430224)
+ self.assertAlmostEqual(wp, 0.0616288455466)
+ self.assertAlmostEqual(wg, 0.176469728448)
+
#! TODO: not yet implemented
# def testMIMOtfdata(self):
# sisotf = ss2tf(self.siso_ss1)
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