Rookie Programmers-Mecanum Help Wanted

Technical NI LabVIEW
1

We are first time programmers, and we have decided to go with a mecanum drive this year. We have been running the default roboRIO Mecanum With Arm code, and we are driving great. However, our driver hates using the z axis (the little dial) for rotating. How would we change it to buttons 4 and 5 on a Logitech Attack 3? It’s the default code, but we can post a picture if you guys think it will help. Thanks!

2

Here is an example of how you can do this, but you will probably need to play with the values and array indices (I don’t have the joystick or your robot sitting here).

The first part is just opening the refnum to the joystick, and assign the X/Y axis to the Holonomic Drive block as usual, but in order to get the Rotation, we simply put it through two Select blocks to get which direction it should turn. Keep in mind that button 4 overrides button 3, but you probably aren’t pushing both buttons at the same time with the same finger.

rotationWithButtons.jpg


rotationWithButtons.jpg

3

what VI do we put this into?

4

You can put this inside of Teleop, sorry.

5

You should read this thread about driver interface. Your driver may be much happier with two 2-axis joysticks instead of just one.
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6

Does anyone know how to do this in Java?

7

Try posting in the Java programming subforum.

8

To use mecanum drive in Java, it’s something simple like using the mecanum drive method of the robot drive class. If you have Java programming questions, please ask them in the Java forum.

9

RobotDrive.java in WPILib

    /**
     * Drive method for Mecanum wheeled robots.
     *
     * A method for driving with Mecanum wheeled robots. There are 4 wheels
     * on the robot, arranged so that the front and back wheels are toed in 45 degrees.
     * When looking at the wheels from the top, the roller axles should form an X across the robot.
     *
     * This is designed to be directly driven by joystick axes.
     *
     * @param x The speed that the robot should drive in the X direction. -1.0..1.0]
     * @param y The speed that the robot should drive in the Y direction.
     * This input is inverted to match the forward == -1.0 that joysticks produce. -1.0..1.0]
     * @param rotation The rate of rotation for the robot that is completely independent of
     * the translation. -1.0..1.0]
     * @param gyroAngle The current angle reading from the gyro.  Use this to implement field-oriented controls.
     */
    public void mecanumDrive_Cartesian(double x, double y, double rotation, double gyroAngle) {
        if(!kMecanumCartesian_Reported) {
            UsageReporting.report(tResourceType.kResourceType_RobotDrive, getNumMotors(), tInstances.kRobotDrive_MecanumCartesian);
            kMecanumCartesian_Reported = true;
        }
10