Drivetrain Examples

Arcade drive implementation for differential drivetrains

This example shows how to implement arcade-style driving where one joystick axis controls forward/backward and another controls turning.

Arcade Drive Example

Java

package edu.wpi.first.wpilibj.examples.arcadedrive;

import edu.wpi.first.util.sendable.SendableRegistry;
import edu.wpi.first.wpilibj.Joystick;
import edu.wpi.first.wpilibj.TimedRobot;
import edu.wpi.first.wpilibj.drive.DifferentialDrive;
import edu.wpi.first.wpilibj.motorcontrol.PWMSparkMax;

/**
 * This is a demo program showing the use of the DifferentialDrive class. Runs the motors with
 * arcade steering.
 */
public class Robot extends TimedRobot {
  private final PWMSparkMax m_leftMotor = new PWMSparkMax(0);
  private final PWMSparkMax m_rightMotor = new PWMSparkMax(1);
  private final DifferentialDrive m_robotDrive =
      new DifferentialDrive(m_leftMotor::set, m_rightMotor::set);
  private final Joystick m_stick = new Joystick(0);

  public Robot() {
    SendableRegistry.addChild(m_robotDrive, m_leftMotor);
    SendableRegistry.addChild(m_robotDrive, m_rightMotor);

    // We need to invert one side of the drivetrain so that positive voltages
    // result in both sides moving forward. Depending on how your robot's
    // gearbox is constructed, you might have to invert the left side instead.
    m_rightMotor.setInverted(true);
  }

  @Override
  public void teleopPeriodic() {
    // Drive with arcade drive.
    // That means that the Y axis drives forward
    // and backward, and the X turns left and right.
    m_robotDrive.arcadeDrive(-m_stick.getY(), -m_stick.getX());
  }
}

C++

#include <frc/Joystick.h>
#include <frc/TimedRobot.h>
#include <frc/drive/DifferentialDrive.h>
#include <frc/motorcontrol/PWMSparkMax.h>

/**
 * This is a demo program showing the use of the DifferentialDrive class.
 * Runs the motors with arcade steering.
 */
class Robot : public frc::TimedRobot {
  frc::PWMSparkMax m_leftMotor{0};
  frc::PWMSparkMax m_rightMotor{1};
  frc::DifferentialDrive m_robotDrive{
      [&](double output) { m_leftMotor.Set(output); },
      [&](double output) { m_rightMotor.Set(output); }};
  frc::Joystick m_stick{0};

 public:
  Robot() {
    wpi::SendableRegistry::AddChild(&m_robotDrive, &m_leftMotor);
    wpi::SendableRegistry::AddChild(&m_robotDrive, &m_rightMotor);

    // We need to invert one side of the drivetrain so that positive voltages
    // result in both sides moving forward. Depending on how your robot's
    // gearbox is constructed, you might have to invert the left side instead.
    m_rightMotor.SetInverted(true);
  }

  void TeleopPeriodic() override {
    // Drive with arcade style
    m_robotDrive.ArcadeDrive(-m_stick.GetY(), -m_stick.GetX());
  }
};

#ifndef RUNNING_FRC_TESTS
int main() {
  return frc::StartRobot<Robot>();
}
#endif

What This Example Demonstrates

DifferentialDrive Class

The DifferentialDrive class provides several drive modes:

Arcade Drive:

arcadeDrive(double xSpeed, double zRotation)

• xSpeed: Forward/backward speed (-1.0 to 1.0)
• zRotation: Rotation speed (-1.0 to 1.0)
• Third parameter (optional): Enable input squaring for finer control at low speeds

Tank Drive:

tankDrive(double leftSpeed, double rightSpeed)

• Direct control of left and right sides
• Good for drivers familiar with tank-style controls

Curvature Drive:

curvatureDrive(double xSpeed, double zRotation, boolean isQuickTurn)

• More like car steering
• isQuickTurn: When true, enables turning in place

Input Squaring

By default, arcadeDrive() squares inputs while preserving sign:

// With squaring (default):
Input: 0.5 → Output: 0.25 (0.5²)
Input: -0.5 → Output: -0.25 (-(0.5²))

// Without squaring:
m_robotDrive.arcadeDrive(xSpeed, rotation, false);

Squaring provides:

• Finer control at low speeds
• More aggressive response at high speeds

Motor Inversion

For a differential drive, motors face opposite directions. Invert one side so positive values drive both forward:

m_rightMotor.setInverted(true);

Which side to invert depends on your mechanical setup.

Joystick Negation

Joysticks return negative values when pushed forward (up). Negate to make forward motion intuitive:

m_robotDrive.arcadeDrive(-m_stick.getY(), -m_stick.getX());

Running in Simulation

1. Open the robot simulator
2. Enable teleoperated mode
3. Use a joystick:
   • Y-axis (forward/back): Push forward to drive forward
   • X-axis (left/right): Push left to turn left

Related Examples

• Tank Drive: Two-stick control for differential drives
• Mecanum Drive: Omnidirectional driving with mecanum wheels
• Swerve Drive: Independent module steering and driving

Source Location

• Java: wpilibjExamples/src/main/java/edu/wpi/first/wpilibj/examples/arcadedrive/Robot.java
• C++: wpilibcExamples/src/main/cpp/examples/ArcadeDrive/cpp/Robot.cpp