Servos in FTC

Overview

Servos provide precise, limited-range movement for arms, claws, and similar mechanisms. Standard servos move to a position and hold it. Continuous rotation servos spin like motors.

Standard vs Continuous Rotation

Feature	Standard Servo	Continuous Rotation (CRServo)
Control	setPosition(0.0 to 1.0) — position	setPosition(0.0) reverse, 0.5 stop, 1.0 forward
Use Cases	Arms, claws, precise angles	Intake rollers, spinners
Config	Servo	CRServo

Basic Servo Use

Position values 0.0–1.0 represent the servo’s range. Check manufacturer specs for actual angular range.

private Servo clawServo;

@Override
public void runOpMode() {
    clawServo = hardwareMap.get(Servo.class, "claw_servo");
    clawServo.setPosition(0.5); // Initial position
    
    waitForStart();
    while (opModeIsActive()) {
        if (gamepad1.a) clawServo.setPosition(0.0);
        else if (gamepad1.b) clawServo.setPosition(1.0);
        telemetry.addData("Position", clawServo.getPosition());
        telemetry.update();
    }
}

Multiple Servos and Gradual Movement

Initialize each servo with a unique hardware map name. For smooth motion, change position in small increments over time. Keep positions within 0.0–1.0 to avoid damage.

Gradual Movement Example

Move servo to target in steps.

double current = clawServo.getPosition();
double target = 1.0;
double step = 0.02;

while (Math.abs(current - target) > 0.01 && opModeIsActive()) {
    current += (current < target ? step : -step);
    current = Math.max(0.0, Math.min(1.0, current));
    clawServo.setPosition(current);
    sleep(20);
}

Further Reading