Package edu.wpi.first.math.kinematics

Class ChassisSpeeds

java.lang.Object
edu.wpi.first.math.kinematics.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 Summary

    Fields 
    Modifier and Type Field Description
    double omegaRadiansPerSecond
    Represents the angular velocity of the robot frame.
    double vxMetersPerSecond
    Represents forward velocity w.r.t the robot frame of reference.
    double vyMetersPerSecond
    Represents sideways velocity w.r.t the robot frame of reference.

  • Constructor Summary

    Constructors 
    Constructor Description
    ChassisSpeeds()
    Constructs a ChassisSpeeds with zeros for dx, dy, and theta.
    ChassisSpeeds​(double vxMetersPerSecond, double vyMetersPerSecond, double omegaRadiansPerSecond)
    Constructs a ChassisSpeeds object.

  • Method Summary

    Modifier and Type Method Description
    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.
    String toString()  

    Methods inherited from class java.lang.Object

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

  • Field Details

  • Constructor Details

    • 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.
      Parameters:
      vxMetersPerSecond - Forward velocity.
      vyMetersPerSecond - Sideways velocity.
      omegaRadiansPerSecond - Angular velocity.

  • Method Details

    • 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.
      Parameters:
      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.
      Returns:
      ChassisSpeeds object representing the speeds in the robot's frame of reference.

    • toString

      public String toString()
      Overrides:
      toString in class Object