Class ChassisSpeeds

  • public class ChassisSpeeds
    extends Object
    Represents the speed of a robot chassis. Although this struct contains similar members compared to a Twist2d, they do NOT represent the same thing. Whereas a Twist2d represents a change in pose w.r.t to the robot frame of reference, this ChassisSpeeds struct represents a velocity w.r.t to the robot frame of reference.

    A strictly non-holonomic drivetrain, such as a differential drive, should never have a dy component because it can never move sideways. Holonomic drivetrains such as swerve and mecanum will often have all three components.

    • Field Detail

      • vxMetersPerSecond

        public double vxMetersPerSecond
        Represents forward velocity w.r.t the robot frame of reference. (Fwd is +)
      • vyMetersPerSecond

        public double vyMetersPerSecond
        Represents sideways velocity w.r.t the robot frame of reference. (Left is +)
      • omegaRadiansPerSecond

        public double omegaRadiansPerSecond
        Represents the angular velocity of the robot frame. (CCW is +)
    • Constructor Detail

      • ChassisSpeeds

        public ChassisSpeeds()
        Constructs a ChassisSpeeds with zeros for dx, dy, and theta.
      • ChassisSpeeds

        public ChassisSpeeds​(double vxMetersPerSecond,
                             double vyMetersPerSecond,
                             double omegaRadiansPerSecond)
        Constructs a ChassisSpeeds object.
        vxMetersPerSecond - Forward velocity.
        vyMetersPerSecond - Sideways velocity.
        omegaRadiansPerSecond - Angular velocity.
    • Method Detail

      • fromFieldRelativeSpeeds

        public static ChassisSpeeds fromFieldRelativeSpeeds​(double vxMetersPerSecond,
                                                            double vyMetersPerSecond,
                                                            double omegaRadiansPerSecond,
                                                            Rotation2d robotAngle)
        Converts a user provided field-relative set of speeds into a robot-relative ChassisSpeeds object.
        vxMetersPerSecond - The component of speed in the x direction relative to the field. Positive x is away from your alliance wall.
        vyMetersPerSecond - The component of speed in the y direction relative to the field. Positive y is to your left when standing behind the alliance wall.
        omegaRadiansPerSecond - The angular rate of the robot.
        robotAngle - The angle of the robot as measured by a gyroscope. The robot's angle is considered to be zero when it is facing directly away from your alliance station wall. Remember that this should be CCW positive.
        ChassisSpeeds object representing the speeds in the robot's frame of reference.