DC Motors and Motor Control

Overview

DC motors drive wheels, arms, and other moving parts. Access motors through the hardwareMap—an FTC SDK object that provides references to configured devices. Declare motors as member variables and initialize them in runOpMode().

Initialization and Basic Control

The name passed to hardwareMap.get() must match your robot configuration. Power values range from -1.0 (full reverse) to 1.0 (full forward).

private DcMotor leftDrive, rightDrive;

@Override
public void runOpMode() {
    leftDrive = hardwareMap.get(DcMotor.class, "left_drive");
    rightDrive = hardwareMap.get(DcMotor.class, "right_drive");
    
    leftDrive.setDirection(DcMotor.Direction.REVERSE); // Adjust for motor mounting
    leftDrive.setZeroPowerBehavior(DcMotor.ZeroPowerBehavior.BRAKE);
    
    waitForStart();
    while (opModeIsActive()) {
        leftDrive.setPower(-gamepad1.left_stick_y);
        rightDrive.setPower(-gamepad1.right_stick_y);
        telemetry.update();
    }
    leftDrive.setPower(0);
    rightDrive.setPower(0);
}

Run Modes and Encoders

Use RUN_WITHOUT_ENCODER for basic power control. Use RUN_USING_ENCODER when you need position feedback. Use RUN_TO_POSITION for moving to a target. Reset encoders before use.

Encoder-Based Movement

Move a motor a set distance using encoder counts.

leftDrive.setMode(DcMotor.RunMode.STOP_AND_RESET_ENCODER);
leftDrive.setMode(DcMotor.RunMode.RUN_USING_ENCODER);

int target = 1000;
leftDrive.setPower(0.5);
while (opModeIsActive() && leftDrive.getCurrentPosition() < target) {
    telemetry.addData("Position", leftDrive.getCurrentPosition());
    telemetry.update();
}
leftDrive.setPower(0);

Further Reading