Differential Drive Odometry
import com.arcrobotics.ftclib.kinematics.wpilibkinematics.DifferentialDriveOdometry
A user can use the differential drive kinematics classes in order to perform odometry. WPILib/FTCLib contains a DifferentialDriveOdometry
class that can be used to track the position of a differential drive robot on the field.
Note: Because this method only uses encoders and a gyro, the estimate of the robot’s position on the field will drift over time, especially as your robot comes into contact with other robots during gameplay. However, odometry is usually very accurate during the autonomous period.
Creating the Odometry Object
0 degrees / radians represents the robot angle when the robot is facing directly toward your opponent’s alliance station. As your robot turns to the left, your gyroscope angle should increase.
The encoder positions must be reset to zero before constructing the DifferentialDriveOdometry
class.
Updating the Robot Pose
The update
method can be used to update the robot’s position on the field. This method must be called periodically, preferably in the periodic()
method of a Subsystem. The update
method returns the new updated pose of the robot. This method takes in the gyro angle of the robot, along with the left encoder distance and right encoder distance.
Ensure your encoder distances are in meters!
Resetting the Robot Pose
The robot pose can be reset via the resetPose
method. This method accepts two arguments – the new field-relative pose and the current gyro angle.
If at any time, you decide to reset your gyroscope, the resetPose
method MUST be called with the new gyro angle. Furthermore, the encoders must also be reset to zero when resetting the pose.
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