Twist2d

Twist2d represents a small motion delta in 2D space: a forward movement (dx), a sideways movement (dy), and a rotation (dtheta).

Why It's Useful

Twist2d is used in the mathematical integration of motion, especially for differential and swerve drive odometry. It provides a way to accumulate small movement changes into a larger Pose2d.

Common Use Cases

• Odometry updates: Used by SwerveDriveOdometry to update robot pose based on wheel encoder and gyro changes

• Simulating movement: Represent small time-step changes in robot motion in simulation or trajectory generation

• Kinematics math: Used in differential and swerve kinematics to compute relative motion between poses or track wheel motions

Twist2d is also the mathematical basis for exponential mapping and logarithmic mapping between poses, which is needed for robot localization.