FIX pid error fixed from previous to current

Author: askuric

src/common/pid.cpp

@@ -25,7 +25,7 @@ float PIDController::operator() (float error){
     // Discrete implementations
     // proportional part 
     // u_p  = P *e(k)
-    float proportional = P * error_prev;
+    float proportional = P * error;
     // Tustin transform of the integral part
     // u_ik = u_ik_1  + I*Ts/2*(ek + ek_1)
     float integral = integral_prev + I*Ts*0.5*(error + error_prev);