SwerveModule Class

The SwerveModule class initializes the swerve module on the robot. The method getState returns a new object of the SwerveModuleState class, allowing us to know the current state according to the linear speed of the throttle in meters per second and the degrees the encoder has rotated. The method setState gets the current heading of the drive and takes a SwerveModuleState object. The method will use a PID controller to turn the drive to the desired heading at a desired speed.

備註

For API specific issues, please see the WPILib API , CTRE API, and the REV Robotics API.

Constructor

Talon FX & CANCoderSPARK MAX & CANCoderSPARK MAX & Analog Absolute Encoder

// 初始化 rotor & throttle 馬達
private WPI_TalonFX mRotor;
private WPI_TalonFX mThrottle;

// 初始化 rotor encoder
private WPI_CANCoder mRotorEncoder;

// 初始化 rotor PID controller
private PIDController mRotorPID;

/**
 * 構建新的 SwerveModule
 *
 * @param throttleID CAN ID of throttle 馬達
 * @param rotorID CAN ID of rotor 馬達
 * @param rotorEncoderID CAN ID of rotor encoder
 * @param rotorOffsetAngleDeg rotor encoder 偏移量
 */
public SwerveModule(int throttleID, int rotorID, int rotorEncoderID, double rotorOffsetAngleDeg)
{
    // 實例化 throttle 馬達
    mThrottle = new WPI_TalonFX(throttleID);

    // 實例化 rotor 馬達
    mRotor = new WPI_TalonFX(rotorID);

    // 實例化 rotor absolute encoder
    mRotorEncoder = new WPI_CANCoder(rotorEncoderID);

    // 重置所有配置（保險起見以免有舊的配置）
    mThrottle.configFactoryDefault();
    mRotor.configFactoryDefault();
    mRotorEncoder.configFactoryDefault();

    // 根據之前的常數配置 rotor 馬達
    mRotor.setInverted(SwerveConstants.kRotorMotorInversion);
    mRotor.configVoltageCompSaturation(Constants.kVoltageCompensation);
    mRotor.enableVoltageCompensation(true);
    mRotor.setNeutralMode(NeutralMode.Brake);

    // 根據之前的常數配置轉向 rotor encoder
    mRotorEncoder.configAbsoluteSensorRange(AbsoluteSensorRange.Signed_PlusMinus180);
    mRotorEncoder.configMagnetOffset(rotorOffsetAngleDeg);
    mRotorEncoder.configSensorDirection(SwerveConstants.kRotorEncoderDirection);
    mRotorEncoder.configSensorInitializationStrategy(
        SensorInitializationStrategy.BootToAbsolutePosition
    );

    // 根據之前的常數配置 rotor 馬達的PID控制器
    mRotorPID = new PIDController(
        SwerveConstants.kRotor_kP,
        SwerveConstants.kRotor_kI,
        SwerveConstants.kRotor_kD
    );

    // ContinuousInput 認為 min 和 max 是同一點並且自動計算到設定點的最短路線
    mRotorPID.enableContinuousInput(-180, 180);

    // 根據之前的常數配置 throttle 馬達
    mThrottle.configSelectedFeedbackSensor(FeedbackDevice.IntegratedSensor);
    mThrottle.configVoltageCompSaturation(Constants.kVoltageCompensation);
    mThrottle.enableVoltageCompensation(true);
    mThrottle.setNeutralMode(NeutralMode.Brake);
}

警告

使用無刷馬達時，強烈建議設置寬鬆的電流限制 以防止損壞馬達。查看 CTRE 和 REV 文檔以獲取有關電流限制的更多信息。

Methods

getState

輸出 swerve module 的當前狀態。

Talon FXSPARK MAX

public SwerveModuleState getState() {
    double throttleVelocity =
        mThrottle.getSelectedSensorVelocity() * SwerveConstants.kThrottleVelocityConversionFactor;

    return new SwerveModuleState(
        throttleVelocity,
        Rotation2d.fromDegrees(mRotorEncoder.getAbsolutePosition())
    );
}

Return:

新的 SwerveModuleState 代表著目前的前進速度和面相角度。

getPosition

Outputs the current position of the swerve module.

Talon FXSPARK MAX

public SwerveModulePosition getPosition() {
    double throttlePosition = mThrottle.getSelectedSensorPosition() * SwerveConstants.kThrottlePositionConversionFactor;

    return new SwerveModulePosition(
        throttlePosition,
        Rotation2d.fromDegrees(mRotorEncoder.getAbsolutePosition())
    );
}

Return:

New SwerveModulePosition representing the current throttle position and rotor angle.

setState

設置 swerve module 的狀態。

public void setState(SwerveModuleState state) {
    // 優化狀態，使轉向馬達不必旋轉超過 90 度來獲得目標的角度
    SwerveModuleState optimizedState = SwerveModuleState.optimize(state, getState().angle);

    // 通過比較目前角度與目標角度來用 PID 控制器計算轉向馬達所需的輸出
    double rotorOutput = mRotorPID.calculate(
        getState().angle.getDegrees(),
        optimizedState.angle.getDegrees()
    );

    mRotor.set(rotorOutput);
    mThrottle.set(optimizedState.speedMetersPerSecond);
}

Parameters:

1. state - 理想的 SwerveModuleState (angle & speed) of SwerveModule

備註

在我們的 Github 上查看我們在這些文檔中使用的代碼！