Package edu.wpi.first.math.kinematics

Class DifferentialDriveOdometry

java.lang.Object

edu.wpi.first.math.kinematics.DifferentialDriveOdometry

public class DifferentialDriveOdometry
extends Object

Class for differential drive odometry. Odometry allows you to track the robot's position on the field over the course of a match using readings from 2 encoders and a gyroscope.

Teams can use odometry during the autonomous period for complex tasks like path following. Furthermore, odometry can be used for latency compensation when using computer-vision systems.

It is important that you reset your encoders to zero before using this class. Any subsequent pose resets also require the encoders to be reset to zero.

Constructor Summary

Constructors

Constructor	Description
DifferentialDriveOdometry(Rotation2d gyroAngle)	Constructs a DifferentialDriveOdometry object with the default pose at the origin.
DifferentialDriveOdometry(Rotation2d gyroAngle, Pose2d initialPoseMeters)	Constructs a DifferentialDriveOdometry object.

Method Summary

Modifier and Type	Method	Description
Pose2d	getPoseMeters()	Returns the position of the robot on the field.
void	resetPosition(Pose2d poseMeters, Rotation2d gyroAngle)	Resets the robot's position on the field.
Pose2d	update(Rotation2d gyroAngle, double leftDistanceMeters, double rightDistanceMeters)	Updates the robot position on the field using distance measurements from encoders.

Methods inherited from class java.lang.Object

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

Constructor Details

DifferentialDriveOdometry

public DifferentialDriveOdometry(Rotation2d gyroAngle, Pose2d initialPoseMeters)

Constructs a DifferentialDriveOdometry object.

Parameters:

gyroAngle - The angle reported by the gyroscope.

initialPoseMeters - The starting position of the robot on the field.

DifferentialDriveOdometry

public DifferentialDriveOdometry(Rotation2d gyroAngle)

Constructs a DifferentialDriveOdometry object with the default pose at the origin.

Parameters:

gyroAngle - The angle reported by the gyroscope.

Method Details

resetPosition

public void resetPosition(Pose2d poseMeters, Rotation2d gyroAngle)

Resets the robot's position on the field.

You NEED to reset your encoders (to zero) when calling this method.

The gyroscope angle does not need to be reset here on the user's robot code. The library automatically takes care of offsetting the gyro angle.

Parameters:

poseMeters - The position on the field that your robot is at.

gyroAngle - The angle reported by the gyroscope.

getPoseMeters

public Pose2d getPoseMeters()

Returns the position of the robot on the field.

Returns:

The pose of the robot (x and y are in meters).

update

public Pose2d update(Rotation2d gyroAngle, double leftDistanceMeters, double rightDistanceMeters)

Updates the robot position on the field using distance measurements from encoders. This method is more numerically accurate than using velocities to integrate the pose and is also advantageous for teams that are using lower CPR encoders.

Parameters:

gyroAngle - The angle reported by the gyroscope.

leftDistanceMeters - The distance traveled by the left encoder.

rightDistanceMeters - The distance traveled by the right encoder.

Returns:

The new pose of the robot.