a fork of priustroller

Dependencies:   mbed

Fork of priustroller_current by N K

Revision:
27:846c08fb3697
Parent:
14:1cc975207995
Child:
33:e7b132029bae
diff -r d00561c7bf43 -r 846c08fb3697 util/transforms.cpp
--- a/util/transforms.cpp	Tue Mar 10 17:51:38 2015 +0000
+++ b/util/transforms.cpp	Sat Mar 14 18:51:36 2015 +0000
@@ -12,16 +12,22 @@
     *b = -0.5 * alpha + sqrt(3.0f) / 2.0f * beta;
 }
 
-void Transforms::Parke(float alpha, float beta, float theta, float *d, float *q) {
+void Transforms::Parke(float beta, float alpha, float theta, float *d, float *q) {  
+    //reversed alpha and beta order to make d and q ~=constant.
+    //I did this because alpha was found to be sinusoidal and beta was found to be cosinusoidal.  the equation has to take the form sin^2 + cos^2, not sin*cos + sin*cos.
     float cos = FastCos(theta);
     float sin = FastSin(theta);
+
     *d = alpha * cos + beta * sin;
     *q = -alpha * sin + beta * cos;
+
 }
 
-void Transforms::InverseParke(float d, float q, float theta, float *alpha, float *beta) {
+void Transforms::InverseParke(float d, float q, float theta, float *alpha, float *beta) {  
     float cos = FastCos(theta);
     float sin = FastSin(theta);
+
     *alpha = cos * d - sin * q;
-    *beta = sin * d + cos * q;                                
+    *beta = sin * d + cos * q; 
+                              
 }
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