Drive Util

NextFTC v2 provides functions to drive mecanum and tank drivetrains from a gamepad, so you don’t have to write the math yourself.

Note

Currently, NextFTC only has driving functions for mecanum and tank (differential) drivetrains. If you write one for another drivetrain, please share it with us!

Register your motors on a Drivetrain mechanism

Kotlin

class Drivetrain : Mechanism {
    val frontLeft = NextMotor(//...)
    val frontRight = NextMotor(//...)
    val backLeft = NextMotor(//...)
    val backRight = NextMotor(//...)
}

Java

public class Drivetrain implements Mechanism {
    public Drivetrain(){}

    public final NextMotor frontLeft = new NextMotor(//...);
    public final NextMotor frontRight = new NextMotor(//...);
    public final NextMotor backLeft = new NextMotor(//...);
    public final NextMotor backRight = new NextMotor(//...);
}

Register it on your NextRobot’s getMechanisms() set, just like any other mechanism.

In your Robot class, add a startDrive method like this:

Kotlin

fun startDrive(gamepad1: Gamepad) {
    mecanumDrive(
        drivetrain.frontLeft,
        drivetrain.frontRight,
        drivetrain.backLeft,
        drivetrain.backRight,
        gamepad1,
    )()
}

Java

public void startDrive(Gamepad gamepad1) {
    DriveCommands.mecanumDrive(
        drivetrain.frontLeft,
        drivetrain.frontRight,
        drivetrain.backLeft,
        drivetrain.backRight,
        gamepad1,
    )();
}

For a tank drivetrain, swap in tankDrive

Call startDrive in your TeleOp

Call this once, in your TeleOp’s constructor and your set!

Kotlin

robot.startDrive(gamepad1)

Java

robot.startDrive(gamepad1);

Field-Centric

mecanumDriveFieldCentric rotates stick input by the robot’s current heading, so “forward” on the stick always moves the robot away from the driver.

Kotlin

mecanumDriveFieldCentric(
    drivetrain.frontLeft,
    drivetrain.frontRight,
    drivetrain.backLeft,
    drivetrain.backRight,
    gamepad1,
    { //insert heading},
)()

Java

DriveCommands.mecanumDriveFieldCentric(
    drivetrain.frontLeft,
    drivetrain.frontRight,
    drivetrain.backLeft,
    drivetrain.backRight,
    gamepad1,
    () -> //insert heading,
)();

Scalars

Multiplies your gamepad inputs by a scalar to support different speed modes or sensitivities.

Kotlin

scalar = 0.5 // makes it half speed

Java

DriveCommands.setScalar(0.5); // makes it half speed

A common way to use Scalar is a slow mode:

Kotlin

gp1.leftBumper().whileTrue(Commands.infinite { scalar = 0.4 })

Java

gp1.leftBumper().whileTrue(Commands.infinite(() -> DriveCommands.setScalar(0.4)));