Motors

DC motors are used for most robot movement and mechanisms.

Examples:

• Drive motors
• Intake motors
• Slides
• Turrets
• Launchers

Getting a Motor

Motors are usually stored as DcMotor objects.

DcMotor motor;

motor = hardwareMap.get(DcMotor.class, "motor");

Motor Power

Motor power controls speed and direction.

Values range from:

-1.0 to 1.0

Example:

motor.setPower(0.5);

Positive power:

Forward

Negative power:

Reverse

Stop a motor:

motor.setPower(0);

Motor Direction

Sometimes motors are mounted in opposite directions.

motor.setDirection(
    DcMotor.Direction.REVERSE
);

The options are:

DcMotor.Direction.FORWARD
DcMotor.Direction.REVERSE

Zero Power Behavior

Controls what happens when power becomes zero.

Brake

The motor stops quickly.

motor.setZeroPowerBehavior(DcMotor.ZeroPowerBehavior.BRAKE);

Float

The motor slowly coasts.

motor.setZeroPowerBehavior(DcMotor.ZeroPowerBehavior.FLOAT);

Motor Modes

Motor modes control how the motor uses encoders.

RUN_WITHOUT_ENCODER

Basic motor control.

motor.setMode(DcMotor.RunMode.RUN_WITHOUT_ENCODER);

RUN_USING_ENCODER

Uses encoder feedback to control speed.

motor.setMode(DcMotor.RunMode.RUN_USING_ENCODER);

STOP_AND_RESET_ENCODER

Resets the encoder position.

motor.setMode(DcMotor.RunMode.STOP_AND_RESET_ENCODER);

RUN_TO_POSITION

Moves to a target encoder position.

motor.setTargetPosition(1000);

motor.setMode(DcMotor.RunMode.RUN_TO_POSITION);

Encoders

Encoders measure motor rotation.

You can read the current position:

int position = motor.getCurrentPosition();

Encoders are useful for:

• Precise movement
• Autonomous routines
• Mechanism control

Although encoders are feedback sensors, FTC programmers usually work with them through motors.

Common Motor Issues

Motor Spins Backwards

Fix the direction:

motor.setDirection(DcMotor.Direction.REVERSE);

Robot Does Not Move

Check:

• Hardware name
• Power value
• Motor connection
• Battery voltage

Motors Fight Each Other

Usually caused by incorrect direction settings.

Key Takeaways

• Motors are controlled with power values.
• Power ranges from -1.0 to 1.0.
• Zero power behavior controls stopping behavior.
• Encoders provide position feedback.
• Motor modes change how motors operate.