MecanumDriveOdometry.h

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// Copyright (c) FIRST and other WPILib contributors.
// Open Source Software; you can modify and/or share it under the terms of
// the WPILib BSD license file in the root directory of this project.
 
#pragma once
 
#include <wpi/SymbolExports.h>
#include <wpi/timestamp.h>
 
#include "frc/geometry/Pose2d.h"
#include "frc/kinematics/MecanumDriveKinematics.h"
#include "frc/kinematics/MecanumDriveWheelSpeeds.h"
#include "units/time.h"
 
namespace frc {
 
/**
 * Class for mecanum drive odometry. Odometry allows you to track the robot's
 * position on the field over a course of a match using readings from your
 * mecanum wheel encoders.
 *
 * 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.
 */
class WPILIB_DLLEXPORT MecanumDriveOdometry {
 public:
  /**
   * Constructs a MecanumDriveOdometry object.
   *
   * @param kinematics The mecanum drive kinematics for your drivetrain.
   * @param gyroAngle The angle reported by the gyroscope.
   * @param wheelPositions The current distances measured by each wheel.
   * @param initialPose The starting position of the robot on the field.
   */
  explicit MecanumDriveOdometry(
      MecanumDriveKinematics kinematics, const Rotation2d& gyroAngle,
      const MecanumDriveWheelPositions& wheelPositions,
      const Pose2d& initialPose = Pose2d{});
 
  /**
   * Resets the robot's position on the field.
   *
   * 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.
   *
   * @param gyroAngle The angle reported by the gyroscope.
   * @param wheelPositions The current distances measured by each wheel.
   * @param pose The position on the field that your robot is at.
   */
  void ResetPosition(const Rotation2d& gyroAngle,
                     const MecanumDriveWheelPositions& wheelPositions,
                     const Pose2d& pose) {
    m_pose = pose;
    m_previousAngle = pose.Rotation();
    m_gyroOffset = m_pose.Rotation() - gyroAngle;
    m_previousWheelPositions = wheelPositions;
  }
 
  /**
   * Returns the position of the robot on the field.
   * @return The pose of the robot.
   */
  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 an angle parameter
   * which is used instead of the angular rate that is calculated from forward
   * kinematics, in addition to the current distance measurement at each wheel.
   *
   * @param gyroAngle The angle reported by the gyroscope.
   * @param wheelPositions The current distances measured by each wheel.
   *
   * @return The new pose of the robot.
   */
  const Pose2d& Update(const Rotation2d& gyroAngle,
                       const MecanumDriveWheelPositions& wheelPositions);
 
 private:
  MecanumDriveKinematics m_kinematics;
  Pose2d m_pose;
 
  MecanumDriveWheelPositions m_previousWheelPositions;
  Rotation2d m_previousAngle;
  Rotation2d m_gyroOffset;
};
 
}  // namespace frc