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Remove encoder velocities methods in DifferentialDriveOdometry (#2147)

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It doesn't make sense to continue to provide a less accurate method of performing odometry
when a more accurate method using distances exists.

This also removes the need to pass DifferentialDriveKinematics to the constructor.
This commit is contained in:
Prateek Machiraju
2019-12-01 02:10:29 -05:00
committed by Peter Johnson
parent b8c1024261
commit 5b73c17f25
10 changed files with 41 additions and 265 deletions
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56
wpilibc/src/main/native/include/frc/kinematics/DifferentialDriveOdometry.h
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@@ -23,33 +23,24 @@ namespace frc {
* path following. Furthermore, odometry can be used for latency compensation
* when using computer-vision systems.
*
* There are two ways of tracking the robot's position on the field with this
* class: one involving using encoder velocities and the other involving encoder
* positions. It is very important that only one type of odometry is used with
* each instantiation of this class.
*
* Note: If you are using the encoder positions / distances method, 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.
* 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.
*/
class DifferentialDriveOdometry {
public:
/**
* Constructs a DifferentialDriveOdometry object.
*
* @param kinematics The differential drive kinematics for your drivetrain.
* @param gyroAngle The angle reported by the gyroscope.
* @param initialPose The starting position of the robot on the field.
*/
explicit DifferentialDriveOdometry(DifferentialDriveKinematics kinematics,
const Rotation2d& gyroAngle,
explicit DifferentialDriveOdometry(const Rotation2d& gyroAngle,
const Pose2d& initialPose = Pose2d());
/**
* Resets the robot's position on the field.
*
* If you are using the encoder distances method instead of the velocity
* method, you NEED to reset your encoders (to zero) when calling this method.
* 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.
@@ -72,24 +63,6 @@ class DifferentialDriveOdometry {
*/
const Pose2d& GetPose() const { return m_pose; }
/**
* Updates the robot's position on the field using forward kinematics and
* integration of the pose over time. This method takes in the current time as
* a parameter to calculate period (difference between two timestamps). The
* period is used to calculate the change in distance from a velocity. This
* also takes in an angle parameter which is used instead of the
* angular rate that is calculated from forward kinematics.
*
* @param currentTime The current time.
* @param gyroAngle The angle reported by the gyroscope.
* @param wheelSpeeds The current wheel speeds.
*
* @return The new pose of the robot.
*/
const Pose2d& UpdateWithTime(units::second_t currentTime,
const Rotation2d& gyroAngle,
const DifferentialDriveWheelSpeeds& wheelSpeeds);
/**
* Updates the robot position on the field using distance measurements from
* encoders. This method is more numerically accurate than using velocities to
@@ -104,30 +77,9 @@ class DifferentialDriveOdometry {
const Pose2d& Update(const Rotation2d& gyroAngle, units::meter_t leftDistance,
units::meter_t rightDistance);
/**
* Updates the robot's position on the field using forward kinematics and
* integration of the pose over time. This method automatically calculates
* the current time to calculate period (difference between two timestamps).
* The period is used to calculate the change in distance from a velocity.
* This also takes in an angle parameter which is used instead of the
* angular rate that is calculated from forward kinematics.
*
* @param gyroAngle The angle reported by the gyroscope.
* @param wheelSpeeds The current wheel speeds.
*
* @return The new pose of the robot.
*/
const Pose2d& Update(const Rotation2d& gyroAngle,
const DifferentialDriveWheelSpeeds& wheelSpeeds) {
return UpdateWithTime(frc2::Timer::GetFPGATimestamp(), gyroAngle,
wheelSpeeds);
}
private:
DifferentialDriveKinematics m_kinematics;
Pose2d m_pose;
units::second_t m_previousTime = -1_s;
Rotation2d m_gyroOffset;
Rotation2d m_previousAngle;