Package frc.robot

Class SwerveConstants

java.lang.Object
frc.robot.SwerveConstants
public final class SwerveConstants extends Object
Central constants for the MARSLib swerve drivetrain.

Students: Modify these values to match your physical robot. All distances are in meters, all angles are in radians, and all speeds are in m/s or rad/s.

  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    static final double
    AUTO_ROTATION_KD
    Derivative gain for autonomous rotation path following.
    static final double
    AUTO_ROTATION_KP
    Proportional gain for autonomous rotation path following.
    static final double
    AUTO_TRANSLATION_KD
    Derivative gain for autonomous translation path following.
    static final double
    AUTO_TRANSLATION_KP
    Proportional gain for autonomous translation path following.
    static final double
    BUMPER_LENGTH_METERS
    Outer dimensions of the robot with bumpers, used for bounding boxes and MoI approximation (m)
    static final double
    BUMPER_WIDTH_METERS
     
    static final double
    DRIVE_GEAR_RATIO
    Drive motor gear ratio (motor rotations per output rotation).
    static final double
    DRIVE_STATOR_CURRENT_LIMIT
    Nominal stator current limit for drive motors (amps).
    static final double
    GRAVITY_M_PER_S2
    Standard gravitational acceleration (m/s²).
    static final double
    LATERAL_SLIP_RELAXATION
    Lateral slip relaxation length (m/s).
    static final double
    MAX_ANGULAR_SPEED_RAD_PER_SEC
    Maximum achievable angular robot speed (rad/s).
    static final double
    MAX_LINEAR_SPEED_MPS
    Maximum achievable linear robot speed (m/s).
    static final double
    MIN_LOAD_SHED_CURRENT
    Minimum current limit during load shedding (amps).
    static final edu.wpi.first.math.geometry.Translation2d[]
    MODULE_LOCATIONS
    Positions of each swerve module relative to robot center (FL, FR, BL, BR).
    static final double
    NOMINAL_BATTERY_VOLTAGE
    Nominal battery voltage used for drive feedforward normalization (V).
    static final double
    ROBOT_MASS_KG
    Mass of the robot inclusive of battery and bumpers (kg).
    static final double
    ROBOT_MOI_KG_M2
    Approximate moment of inertia of the robot based on a solid block model (kg*m^2)
    static final double
    SLIP_TRANSITION_VELOCITY_MPS
    Slip velocity threshold (m/s) at which static friction transitions to kinetic.
    static final double
    TRACK_WIDTH_METERS
    Distance between left and right module centers (meters).
    static final double
    TURN_GEAR_RATIO
    Turn motor gear ratio (motor rotations per module rotation).
    static final double
    TURN_KP
    Proportional gain for the module turn voltage controller.
    static final double
    TURN_STATOR_CURRENT_LIMIT
    Nominal stator current limit for turn motors (amps).
    static final double
    WALL_FRICTION
    Coefficient of friction for robot bumpers scraping against field walls.
    static final double
    WALL_RESTITUTION
    Coefficient of restitution (bounciness) for robot-to-wall collisions.
    static final double
    WHEEL_COF_KINETIC
    Kinetic coefficient of friction once the wheel breaks traction (wheel slip/burnout).
    static final double
    WHEEL_COF_STATIC
    Static coefficient of friction of the tread against standard FRC carpet.
    static final double
    WHEEL_MOI_KG_M2
    Effective rotational inertia of a single driven wheel assembly including the Kraken X60 rotor reflected through the DRIVE_GEAR_RATIO (kg·m²).
    static final double
    WHEEL_RADIUS_METERS
    Radius of the swerve drive wheels (meters).
    static final double
    WHEELBASE_METERS
    Distance between front and rear module centers (meters).

  • Method Summary

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

    • TRACK_WIDTH_METERS

      public static final double TRACK_WIDTH_METERS
      Distance between left and right module centers (meters).
      See Also:

    • WHEELBASE_METERS

      public static final double WHEELBASE_METERS
      Distance between front and rear module centers (meters).
      See Also:

    • MODULE_LOCATIONS

      public static final edu.wpi.first.math.geometry.Translation2d[] MODULE_LOCATIONS
      Positions of each swerve module relative to robot center (FL, FR, BL, BR).

    • ROBOT_MASS_KG

      public static final double ROBOT_MASS_KG
      Mass of the robot inclusive of battery and bumpers (kg). 140lbs.
      See Also:

    • BUMPER_LENGTH_METERS

      public static final double BUMPER_LENGTH_METERS
      Outer dimensions of the robot with bumpers, used for bounding boxes and MoI approximation (m)
      See Also:

    • BUMPER_WIDTH_METERS

      public static final double BUMPER_WIDTH_METERS
      See Also:

    • ROBOT_MOI_KG_M2

      public static final double ROBOT_MOI_KG_M2
      Approximate moment of inertia of the robot based on a solid block model (kg*m^2)

    • WHEEL_COF_STATIC

      public static final double WHEEL_COF_STATIC
      Static coefficient of friction of the tread against standard FRC carpet.
      See Also:

    • WHEEL_COF_KINETIC

      public static final double WHEEL_COF_KINETIC
      Kinetic coefficient of friction once the wheel breaks traction (wheel slip/burnout).
      See Also:

    • SLIP_TRANSITION_VELOCITY_MPS

      public static final double SLIP_TRANSITION_VELOCITY_MPS
      Slip velocity threshold (m/s) at which static friction transitions to kinetic.

      Below this velocity, wheel grip uses WHEEL_COF_STATIC. Above it, grip drops to WHEEL_COF_KINETIC, modeling the Stribeck/Coulomb friction curve.

      See Also:

    • LATERAL_SLIP_RELAXATION

      public static final double LATERAL_SLIP_RELAXATION
      Lateral slip relaxation length (m/s). Controls the viscous ramp region for sideways tire friction to prevent numerical jitter at low lateral velocities.
      See Also:

    • WHEEL_MOI_KG_M2

      public static final double WHEEL_MOI_KG_M2
      Effective rotational inertia of a single driven wheel assembly including the Kraken X60 rotor reflected through the DRIVE_GEAR_RATIO (kg·m²).
      See Also:

    • GRAVITY_M_PER_S2

      public static final double GRAVITY_M_PER_S2
      Standard gravitational acceleration (m/s²).
      See Also:

    • WALL_FRICTION

      public static final double WALL_FRICTION
      Coefficient of friction for robot bumpers scraping against field walls.
      See Also:

    • WALL_RESTITUTION

      public static final double WALL_RESTITUTION
      Coefficient of restitution (bounciness) for robot-to-wall collisions.
      See Also:

    • WHEEL_RADIUS_METERS

      public static final double WHEEL_RADIUS_METERS
      Radius of the swerve drive wheels (meters). Standard 2-inch colson = 0.0508m.
      See Also:

    • MAX_LINEAR_SPEED_MPS

      public static final double MAX_LINEAR_SPEED_MPS
      Maximum achievable linear robot speed (m/s).
      See Also:

    • MAX_ANGULAR_SPEED_RAD_PER_SEC

      public static final double MAX_ANGULAR_SPEED_RAD_PER_SEC
      Maximum achievable angular robot speed (rad/s).
      See Also:

    • NOMINAL_BATTERY_VOLTAGE

      public static final double NOMINAL_BATTERY_VOLTAGE
      Nominal battery voltage used for drive feedforward normalization (V).

      This is the true battery nominal (12.0V), NOT the load-shedding trigger threshold (PowerConstants.NOMINAL_VOLTAGE). Used in SwerveModule.setDesiredState(edu.wpi.first.math.kinematics.SwerveModuleState) to scale desired speed into voltage.

      See Also:

    • DRIVE_GEAR_RATIO

      public static final double DRIVE_GEAR_RATIO
      Drive motor gear ratio (motor rotations per output rotation). L1 = 6.75:1.
      See Also:

    • TURN_GEAR_RATIO

      public static final double TURN_GEAR_RATIO
      Turn motor gear ratio (motor rotations per module rotation).
      See Also:

    • DRIVE_STATOR_CURRENT_LIMIT

      public static final double DRIVE_STATOR_CURRENT_LIMIT
      Nominal stator current limit for drive motors (amps).
      See Also:

    • TURN_STATOR_CURRENT_LIMIT

      public static final double TURN_STATOR_CURRENT_LIMIT
      Nominal stator current limit for turn motors (amps).
      See Also:

    • MIN_LOAD_SHED_CURRENT

      public static final double MIN_LOAD_SHED_CURRENT
      Minimum current limit during load shedding (amps).
      See Also:

    • TURN_KP

      public static final double TURN_KP
      Proportional gain for the module turn voltage controller.
      See Also:

    • AUTO_TRANSLATION_KP

      public static final double AUTO_TRANSLATION_KP
      Proportional gain for autonomous translation path following.
      See Also:

    • AUTO_TRANSLATION_KD

      public static final double AUTO_TRANSLATION_KD
      Derivative gain for autonomous translation path following.
      See Also:

    • AUTO_ROTATION_KP

      public static final double AUTO_ROTATION_KP
      Proportional gain for autonomous rotation path following.
      See Also:

    • AUTO_ROTATION_KD

      public static final double AUTO_ROTATION_KD
      Derivative gain for autonomous rotation path following.
      See Also: