Revision 1:ce626b794a6c, committed 2017-08-25

Comitter:

dudu941014

Date:

Fri Aug 25 21:25:46 2017 +0000

Parent:

0:489498e8dae5

Commit message:

this code is for inverted pendulum balancer. it is based on two-loop PID controller. One controller is for Angle and another one is for velocity.

Changed in this revision

--- a/PID/PID.cpp	Fri Aug 25 21:10:23 2017 +0000
+++ b/PID/PID.cpp	Fri Aug 25 21:25:46 2017 +0000
@@ -95,30 +95,31 @@
 {
     float output;
     
-    pid->outP = pid->kp * pid->error;   //P
+    pid->outP = pid->kp * pid->error;   //calculate the output of P_term according to PID control theroy 
     
     //pid->outI += pid->ki * pid->error * pid->dt;    //I
-    pid->outI = -pid->ki * distance * 10;
+    pid->outI = -pid->ki * distance * 10;//calculate the output of I_term according to PID control theroy
+                                        //this code is the difference between Velocity PID and Angle PID
 
-    if (pid->outI > pid->iLimit)
+    if (pid->outI > pid->iLimit)//this part is to limit the output of I_term
     {
         pid->outI = pid->iLimit;
     }   
-    else if (pid->outI < pid->iLimitLow)
+    else if (pid->outI < pid->iLimitLow)//this part is to limit the output of I_term
     {
         pid->outI = pid->iLimitLow;
     }
     
     I_term_parameter = pid->outI;
     
-    pid->deri = (pid->error - pid->prevError) / pid->dt;    //D
+    pid->deri = (pid->error - pid->prevError) / pid->dt;   //calculate the output of D_term according to PID control theroy 
     pid->prevError = pid->error;
     
-    pid->outD = pid->kd * pid->deri;
+    pid->outD = pid->kd * pid->deri;//calculate the output of D_term according to PID control theroy 
     
-    output = pid->outP + pid->outI + pid->outD;
+    output = pid->outP + pid->outI + pid->outD;//calculate the P I D terms' output and returen the OUTPUT 
     
-    return output;
+    return output;//returen the total OUTPUT 
 }