Challenge- Create a MoveDistance Command

Challenge: The moveDistance() Method

Now that you know how to use an Encoder, let's make a new method called moveDistance at the bottom of the XRPDrivetrain class. Remember when I said we'll use the MoveRobot command for later?

Conditions:

• Has 1 parameter- double distance.

• Returns nothing.

• Should move in a straight line at the speed given in parameters. Once it travels the set distance on the encoder, it should immediately stop moving.

• Should use the moveRobot() method for simplicity.

Hint #1

Try to use either the command's execute() or the subsystem's periodic() function.

Answer Code

/*Example moveDistance method. This is a subsystem version. Imagine this is
 a chunk from the XRPDrivetrain. */

private double targetDistance = 0;
private double averageDistance = 0;

// filler things

public void setDistanceTarget(double newDistance) {
    targetDistance = newDistance;
}

// code that you want

public void periodic() {
    averageDistance = 
    (Math.abs(m_leftEncoder.getDistance()) + 
    Math.abs(m_rightEncoder.getDistance())) / 2.0;
    
    if (averageDistance  < targetDistance) {
        moveMotors(lSpeed, rSpeed);
        
    } else {
        moveMotors(0, 0);
        
        /* if you want to, you can create a debounce variable
        * that gets activated if you call the moveDistance() method, and
        * resets the speed.
        */
    }
}

Answer Code (alternate)

/*Example moveDistance() method. This is a command version. */

private double distance = 0;
private RomiDrivetrain subsystem = RomiDrivetrain:GetInstance()

// filler things

// [stuff]
public void execute() {
    // getRightDistanceInch() works too
    if (subsystem.getLeftDistanceInch() < distance) {
        moveMotors(lSpeed, rSpeed);
        
    } else {
        moveMotors(0, 0);
        
        /* if you want to, you can create a debounce variable
        * that gets activated if you call the moveDistance() method, and
        * resets the speed (google up debounce variable)
        */
    }
}

public void isFinished() {
    // once this returns true, this returns true, making 
    // command scheduler end the command
    return (subsystem.getLeftDistanceInch() >= distance);
}