Lesson 3: 2-Motor Arcade Tank Drive

Arcade tank drive controls a differential drivetrain using two joystick axes — the left stick’s Y axis for forward/reverse speed and the left stick’s X axis for turning. This lesson implements a complete 2-motor arcade drive from scratch: you’ll declare a left and right motor, invert the right side so both motors push the robot in the same direction, and implement the drive loop inside teleopPeriodic().

What You’ll Learn

How to declare two motors (m_leftMotor and m_rightMotor) for a differential drivetrain
Why the right-side motor must be inverted and how to do it for each motor type
How to read joystick axes with getLeftY() and getLeftX() from CommandXboxController
The arcade drive math formula: leftOutput = speed + turn, rightOutput = speed - turn
How to clamp outputs with MathUtil.clamp() to stay within the valid -1.0 to 1.0 range

Arcade Drive Math

Arcade drive combines a single forward/backward speed value with a rotation value to produce independent left and right motor outputs:

double forward = -driverController.getLeftY(); // negate: up = positive
double turn = driverController.getLeftX();
double leftSpeed = forward + turn;
double rightSpeed = forward - turn;
leftSpeed = MathUtil.clamp(leftSpeed, -1.0, 1.0);
rightSpeed = MathUtil.clamp(rightSpeed, -1.0, 1.0);

Straight forward: turn = 0 → both sides get the same speed.
Turn right: turn > 0 → left side speeds up, right side slows down → robot arcs right.
Turn left: turn < 0 → right side speeds up, left side slows down → robot arcs left.
Spin in place: speed = 0, turn ≠ 0 → one side drives forward, the other reverse.

The left Y axis is negated (-driverController.getLeftY()) because WPILib follows joystick convention: pushing the stick forward produces a negative value. Negating it converts “up = positive,” which is the expected behavior for forward drive.

Solutions by Motor Type

NEO (SparkMax)
Kraken (TalonFX)
CIM (PWMSparkMax)

The right motor is inverted via SparkMaxConfig so that both motors push the robot forward when given a positive setpoint. The drive loop runs every cycle inside teleopPeriodic().

import edu.wpi.first.wpilibj.TimedRobot;
import edu.wpi.first.wpilibj2.command.CommandXboxController;
import edu.wpi.first.math.MathUtil;
import com.revrobotics.spark.SparkMax;
import com.revrobotics.spark.SparkLowLevel.MotorType;
import com.revrobotics.spark.config.SparkMaxConfig;
import com.revrobotics.spark.SparkBase.ResetMode;
import com.revrobotics.spark.SparkBase.PersistMode;

public class Robot extends TimedRobot {
    private final SparkMax m_leftMotor = new SparkMax(1, MotorType.kBrushless);
    private final SparkMax m_rightMotor = new SparkMax(2, MotorType.kBrushless);
    private final CommandXboxController driverController = new CommandXboxController(0);
    private final CommandXboxController operatorController = new CommandXboxController(1);

    @Override
    public void robotInit() {
        SparkMaxConfig rightConfig = new SparkMaxConfig();
        rightConfig.inverted(true);
        m_rightMotor.configure(rightConfig, ResetMode.kResetSafeParameters, PersistMode.kPersistParameters);
    }

    @Override
    public void teleopPeriodic() {
        double forward = -driverController.getLeftY();
        double turn = driverController.getLeftX();
        double leftSpeed = forward + turn;
        double rightSpeed = forward - turn;
        leftSpeed = MathUtil.clamp(leftSpeed, -1.0, 1.0);
        rightSpeed = MathUtil.clamp(rightSpeed, -1.0, 1.0);
        m_leftMotor.set(leftSpeed);
        m_rightMotor.set(rightSpeed);
    }
}

The Kraken uses MotorOutputConfigs for inversion and DutyCycleOut control requests for motor output.

import edu.wpi.first.wpilibj.TimedRobot;
import edu.wpi.first.wpilibj2.command.CommandXboxController;
import edu.wpi.first.math.MathUtil;
import com.ctre.phoenix6.hardware.TalonFX;
import com.ctre.phoenix6.controls.DutyCycleOut;
import com.ctre.phoenix6.configs.MotorOutputConfigs;
import com.ctre.phoenix6.signals.InvertedValue;

public class Robot extends TimedRobot {
    private final TalonFX m_leftMotor = new TalonFX(1, "DINO");
    private final TalonFX m_rightMotor = new TalonFX(2, "DINO");
    private final CommandXboxController driverController = new CommandXboxController(0);
    private final CommandXboxController operatorController = new CommandXboxController(1);

    @Override
    public void robotInit() {
        var rightConfig = new MotorOutputConfigs();
        rightConfig.Inverted = InvertedValue.Clockwise_Positive;
        m_rightMotor.getConfigurator().apply(rightConfig);
    }

    @Override
    public void teleopPeriodic() {
        double forward = -driverController.getLeftY();
        double turn = driverController.getLeftX();
        double leftSpeed = forward + turn;
        double rightSpeed = forward - turn;
        leftSpeed = MathUtil.clamp(leftSpeed, -1.0, 1.0);
        rightSpeed = MathUtil.clamp(rightSpeed, -1.0, 1.0);
        m_leftMotor.setControl(new DutyCycleOut(leftSpeed));
        m_rightMotor.setControl(new DutyCycleOut(rightSpeed));
    }
}

PWM controllers use WPILib’s setInverted() method directly on the motor object. The drive math and loop are identical to the NEO version.

import edu.wpi.first.wpilibj.TimedRobot;
import edu.wpi.first.wpilibj2.command.CommandXboxController;
import edu.wpi.first.math.MathUtil;
import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;

public class Robot extends TimedRobot {
    private final PWMSparkMax m_leftMotor = new PWMSparkMax(0);
    private final PWMSparkMax m_rightMotor = new PWMSparkMax(1);
    private final CommandXboxController driverController = new CommandXboxController(0);
    private final CommandXboxController operatorController = new CommandXboxController(1);

    @Override
    public void robotInit() {
        m_rightMotor.setInverted(true);
    }

    @Override
    public void teleopPeriodic() {
        double forward = -driverController.getLeftY();
        double turn = driverController.getLeftX();
        double leftSpeed = forward + turn;
        double rightSpeed = forward - turn;
        leftSpeed = MathUtil.clamp(leftSpeed, -1.0, 1.0);
        rightSpeed = MathUtil.clamp(rightSpeed, -1.0, 1.0);
        m_leftMotor.set(leftSpeed);
        m_rightMotor.set(rightSpeed);
    }
}

Motor Inversion

On a differential drivetrain, the left and right motors face opposite directions — if you send both the same positive setpoint, the robot will spin in place instead of driving straight. Inverting one side corrects this so a positive value always means “push the robot forward.” The method for inverting differs by motor type: NEO (SparkMax) — Configuration API REV SPARK MAX uses the SparkMaxConfig object. You create a config, call .inverted(true), then apply it with .configure():

SparkMaxConfig rightConfig = new SparkMaxConfig();
rightConfig.inverted(true);
m_rightMotor.configure(rightConfig, ResetMode.kResetSafeParameters, PersistMode.kPersistParameters);

ResetMode.kResetSafeParameters clears previous settings before applying. PersistMode.kPersistParameters saves the configuration to the controller’s flash memory so it survives a power cycle. Kraken (TalonFX) — MotorOutputConfigs CTRE Phoenix 6 uses a MotorOutputConfigs object applied via the device configurator:

var rightConfig = new MotorOutputConfigs();
rightConfig.Inverted = InvertedValue.Clockwise_Positive;
m_rightMotor.getConfigurator().apply(rightConfig);

CIM (PWMSparkMax) — setInverted() PWM controllers use WPILib’s simpler setInverted() method directly on the motor object:

m_rightMotor.setInverted(true);

In FRC Academy

To reach this lesson in the app:

Open the Main Menu

Launch FRC Academy and click Motors from the main menu.

Select a motor type

Choose NEO, Kraken, or CIM.

Open Lesson 3

Select 3. 2 Motor Tank Drive (Arcade) from the lesson list.

Choose a mode

Pick Guided Mode or Unguided Mode and start coding.

Always test your drivetrain direction on the ground (or with the robot elevated) before a match. If the robot spins in place when you push the stick forward, your inversion is backwards. If it drives in the wrong direction entirely, check which side you inverted.

4-Motor Tank Drive →

Lesson 4 — Add follower motors to each drivetrain side for a full 4-motor arcade drive setup.

← Activate a Motor

Lesson 2 — Bind a controller button to run a single motor at 50% speed.

Get Started

Learning Paths

Motor Types

Lessons

Lesson 3: 2-Motor Arcade Tank Drive

What You’ll Learn

Arcade Drive Math

Solutions by Motor Type

Motor Inversion

In FRC Academy

4-Motor Tank Drive →

← Activate a Motor

Build docs developers (and LLMs) love

Get Started

Learning Paths

Motor Types

Lessons

Documentation Index

​What You’ll Learn

​Arcade Drive Math

​Solutions by Motor Type

​Motor Inversion

​In FRC Academy

4-Motor Tank Drive →

← Activate a Motor

Build docs developers (and LLMs) love

What You’ll Learn

Arcade Drive Math

Solutions by Motor Type

Motor Inversion

In FRC Academy