Robot not stopping in P loop

[certi.noff]

robot wont stop, im verryyy new to programming please help.

//DRIVE PID
void drivePID(double target){
  double current = 0;
  double error = target-current;
  double kp = .8; //change this//
  double speed = 0;
  
  rightB.resetPosition();
  while(fabs(error)> 0){
    current = rightB.position(deg);
    speed = kp*error;

    rightB.spin(reverse,speed, volt);
    rightF.spin(reverse,speed, volt);
    rightM.spin(reverse,speed, volt);
    leftB.spin(reverse,speed, volt);
    leftF.spin(reverse,speed, volt);
    leftM.spin(reverse,speed, volt);
    error = (target - current);
  }
  rightB.stop(brake);
  rightM.stop(brake);
  rightF.stop(brake);
  leftB.stop(brake);
  leftM.stop(brake);
  leftF.stop(brake);
  
}
void autonomous(void) {
  drivePID(1000);
}

[4233XBen]

Basically, its not stopping because your environment is not perfect you are saying that their needs to be 0 units of error which is almost impossible for a P loop or anything to perform so it just keeps going back and forth (oscillating) correct? So what I recommend is changing this

  while(fabs(error)> 0){

to something like this

  while(fabs(error)> 1){ // If this still happens increase

[certi.noff]

no its not oscillating, it keeps driving forward and wont stop.

[4233XBen]

Oh, I know what it is I had this problem too :

Auton/Drive Switch Issue

I was having an issue when switching between Auton and Drive and back with my switch, after I switched to auton my robot display broke and the motors kept going infinitely until I stopped them and after I switched back to usercontrol nothing would happen (User control worked originally). Here is my main code : #include"myRobot.h" // Includes My Library using namespace vex; // Exports All of the functions and types in namespace "vex" using namespace DisplayControls; // Exports All of the funct…

Anyway what you need is a wait, for like 15 milliseconds or something.
Vex Api functions like .position(deg) don’t have a wait in them and therefore don’t work correctly without a wait in the loop.
Your code should look something like this :

void drivePID(double target){
  double current = 0;
  double error = target-current;
  double kp = .8; //change this//
  double speed = 0;
  
  rightB.resetPosition();
  while(fabs(error)> 0){
    current = rightB.position(deg);
    speed = kp*error;

    rightB.spin(reverse,speed, volt);
    rightF.spin(reverse,speed, volt);
    rightM.spin(reverse,speed, volt);
    leftB.spin(reverse,speed, volt);
    leftF.spin(reverse,speed, volt);
    leftM.spin(reverse,speed, volt);
    error = (target - current);
    task::sleep(15); // Change this to what ever you want just a wait
  }
  rightB.stop(brake);
  rightM.stop(brake);
  rightF.stop(brake);
  leftB.stop(brake);
  leftM.stop(brake);
  leftF.stop(brake);
  
}
void autonomous(void) {
  drivePID(1000);
}