Translation, Rotation, and Pose
Translation
Translation in 2 dimensions is represented by WPILib’s Translation2d
class (Java, C++, Python
). This class has an x and y component, representing the point \((x, y)\) or the vector \(\begin{bmatrix}x \\ y \end{bmatrix}\) on a 2-dimensional coordinate system.
You can get the distance to another Translation2d
object by using the getDistance(Translation2d other)
, which returns the distance to another Translation2d by using the Pythagorean theorem.
Note
Translation2d
uses the C++ Units library. If you’re planning on using other WPILib classes that use Translation2d
in Java/Python, such as the trajectory generator, make sure to use meters.
Rotation
Rotation in 2 dimensions is represented by WPILib’s Rotation2d
class (Java, C++, Python
). This class has an angle component, which represents the robot’s rotation relative to an axis on a 2-dimensional coordinate system. Positive rotations are counterclockwise.
Note
Rotation2d
uses the C++ Units library. The constructor in Java/Python accepts either the angle in radians, or the sine and cosine of the angle, but the fromDegrees
method will construct a Rotation2d
object from degrees.
Note
Rotation2d
does not wrap the value of the angle, so if a value of 400 degrees is passed into the constructor, then 400 degrees will be returned in subsequent value calls.
Pose
Pose is a combination of both translation and rotation and is represented by the Pose2d
class (Java, C++, Python
). It can be used to describe the pose of your robot in the field coordinate system, or the pose of objects, such as vision targets, relative to your robot in the robot coordinate system. Pose2d
can also represent the vector \(\begin{bmatrix}x \\ y \\ \theta\end{bmatrix}\).