Diff: GPA.cpp

Revision:

12:c8ec698c53ed

Parent:

7:7715f92c5182

diff -r 76538cb0bb96 -r c8ec698c53ed GPA.cpp
--- a/GPA.cpp	Mon Jan 07 13:46:28 2019 +0000
+++ b/GPA.cpp	Thu Feb 07 09:08:47 2019 +0000
@@ -1,12 +1,28 @@
 /*
-    GPA: Frequency point wise gain and phase analyser to measure the frequency
-         respone function (FRF) of a dynamical system
+    GPA: Frequency point wise gain and phase analyser to measure the frequency respone function (FRF) of a dynamical system, based on the one point DFT
+
+         Hint:        If the plant has a pole at zero, is unstable or weakly damped the measurement has to be perfomed
+                      in closed loop (this is NOT tfestimate, the algorithm is based on the one point DFT).
+         Assumption:  The system is and remains at the desired steady state of interest when the measurment starts
 
-         Hint:       If the plant has a pole at zero, is unstable or weakly damped the measurement has to be perfomed in closed loop
-         Assumption: The system is at the desired steady state of interest when the measurment starts
+    Instantiate option 0: ("Not a Jedi yet" users, for logarithmic equaly spaced frequency points)
+    
+        GPA(float fMin, float fMax, int NfexcDes, float Aexc0, float Aexc1, float Ts)
+        
+            fMin:       Minimal desired frequency that should be measured in Hz
+            fMax:       Maximal desired frequency that should be measured in Hz
+            NfexcDes:   Number of logarithmic equaly spaced frequency points between fMin and fMax
+            Aexc0:      Excitation amplitude at fMin
+            Aexc1:      Excitation amplitude at fMax
+            Ts:         Sampling time in sec
+            
+            Default values are as follows:
+            int NperMin   = 3;
+            int NmeasMin  = (int)ceil(1.0f/Ts);
+            int NstartMin = (int)ceil(3.0f/Ts);
+            int NsweepMin = 0;
 
-
-    Instantiate option 1: (logarithmic equaly spaced frequency points)
+    Instantiate option 1: ("Jedi or Sith Lord", for logarithmic equaly spaced frequency points)
     
         GPA(float fMin, float fMax, int NfexcDes, int NperMin, int NmeasMin, float Ts, float Aexc0, float Aexc1, int NstartMin, int NsweepMin)
         
@@ -15,7 +31,7 @@
             NfexcDes:   Number of logarithmic equaly spaced frequency points
             NperMin:    Minimal number of periods that are used for each frequency point
             NmeasMin:   Minimal number of samples that are used for each frequency point
-            Ts:         Sampling time
+            Ts:         Sampling time in sec
             Aexc0:      Excitation amplitude at fMin
             Aexc1:      Excitation amplitude at fMax
             NstartMin:  Minimal number of samples to sweep to the first frequency point (can be equal 0)
@@ -30,7 +46,8 @@
             f1:         Frequency point for the calculation of Aexc1 in Hz (should be chosen like in the first measurement)
             *fexcDes:   Sorted frequency point array in Hz
             NfexcDes:   Length of fexcDes
-
+            
+            For the other parameters see above.
 
     Instantiate option 3: (for an arbitary but sorted frequency grid measurement)
     
@@ -40,11 +57,12 @@
             Aexc0:      Excitation amplitude at fexcDes[0]
             Aexc1:      Excitation amplitude at fexcDes[NfexcDes-1]
             NfexcDes:   Length of fexcDes
-
+            
+            For the other parameters see above.
 
-    Note:     The amplitude drops with 1/fexc, if you're using Axc1 = Aexc0/fMax then d/dt exc = const.,
-              this is recommended if your controller does not have a rolloff. If a desired frequency point
-              is not measured try to increase Nmeas (could not be reached).
+    Note:   The amplitude drops with 1/fexc, if you're using Axc1 = Aexc0/fMax then d/dt exc = const.,
+            this is recommended if your controller does not have a rolloff. If a desired frequency point
+            is not measured (could not be reached) try to increase Nmeas.
               
         
     Block diagram:
@@ -145,6 +163,25 @@
 //      instantiate
 // -----------------------------------------------------------------------------
 
+GPA::GPA(float fMin, float fMax, int NfexcDes, float Aexc0, float Aexc1, float Ts)
+{
+    int NperMin = 3;
+    int NmeasMin = (int)ceil(1.0f/Ts);
+    int NstartMin = (int)ceil(3.0f/Ts);
+    int NsweepMin = 0;
+    
+    assignParameters(NfexcDes, NperMin, NmeasMin, (double)Ts, NstartMin, NsweepMin);
+
+    // calculate logarithmic spaced frequency points
+    fexcDes = (double*)malloc(NfexcDes*sizeof(double));
+    fexcDesLogspace((double)fMin, (double)fMax, NfexcDes);
+
+    calculateDecreasingAmplitudeCoefficients((double)Aexc0, (double)Aexc1);
+    initializeConstants((double)Ts);
+    assignFilterStorage();
+    reset();
+}
+
 GPA::GPA(float fMin, float fMax, int NfexcDes, int NperMin, int NmeasMin, float Ts, float Aexc0, float Aexc1, int NstartMin, int NsweepMin)
 {
     assignParameters(NfexcDes, NperMin, NmeasMin, (double)Ts, NstartMin, NsweepMin);