Programación de interruptores de límite

Limit switches are often used to control mechanisms on robots. While limit switches are simple to use, they only can sense a single position of a moving part. This makes them ideal for ensuring that movement doesn’t exceed some limit but not so good at controlling the speed of the movement as it approaches the limit. For example, a rotational shoulder joint on a robot arm would best be controlled using a potentiometer or an absolute encoder. A limit switch could make sure that if the potentiometer ever failed, the limit switch would stop the robot from going too far and causing damage.

Los interruptores de límite pueden tener salidas «normalmente abiertas» o «normalmente cerradas». Esto controlará si una señal alta significa que el interruptor está abierto o cerrado. Para obtener más información sobre el hardware del interruptor de límite, consulte este artículo.

Control de un motor con dos interruptores de límite

JAVA

DigitalInput toplimitSwitch = new DigitalInput(0);
DigitalInput bottomlimitSwitch = new DigitalInput(1);
PWMVictorSPX motor = new PWMVictorSPX(0);
Joystick joystick = new Joystick(0);

@Override
public void teleopPeriodic() {
    setMotorSpeed(joystick.getRawAxis(2));
}

public void setMotorSpeed(double speed) {
    if (speed > 0) {
        if (toplimitSwitch.get()) {
            // We are going up and top limit is tripped so stop
            motor.set(0);
        } else {
            // We are going up but top limit is not tripped so go at commanded speed
            motor.set(speed);
        }
    } else {
        if (bottomlimitSwitch.get()) {
            // We are going down and bottom limit is tripped so stop
            motor.set(0);
        } else {
            // We are going down but bottom limit is not tripped so go at commanded speed
            motor.set(speed);
        }
    }
}

C++

frc::DigitalInput toplimitSwitch {0};
frc::DigitalInput bottomlimitSwitch {1};
frc::PWMVictorSPX motor {0};
frc::Joystick joystick {0};

void TeleopPeriodic() {
    SetMotorSpeed(joystick.GetRawAxis(2));
}

void SetMotorSpeed(double speed) {
    if (speed > 0) {
        if (toplimitSwitch.Get()) {
            // We are going up and top limit is tripped so stop
            motor.Set(0);
        } else {
            // We are going up but top limit is not tripped so go at commanded speed
            motor.Set(speed);
        }
    } else {
        if (bottomlimitSwitch.Get()) {
            // We are going down and bottom limit is tripped so stop
            motor.Set(0);
        } else {
            // We are going down but bottom limit is not tripped so go at commanded speed
            motor.Set(speed);
        }
    }
}