DifferentialDriveKinematicsConstraint.hpp

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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 <utility>
 
#include "wpi/math/kinematics/DifferentialDriveKinematics.hpp"
#include "wpi/math/trajectory/constraint/TrajectoryConstraint.hpp"
#include "wpi/units/velocity.hpp"
#include "wpi/util/SymbolExports.hpp"
 
namespace wpi::math {
/**
 * A class that enforces constraints on the differential drive kinematics.
 * This can be used to ensure that the trajectory is constructed so that the
 * commanded velocities for both sides of the drivetrain stay below a certain
 * limit.
 */
class WPILIB_DLLEXPORT DifferentialDriveKinematicsConstraint
    : public TrajectoryConstraint {
 public:
  constexpr DifferentialDriveKinematicsConstraint(
      DifferentialDriveKinematics kinematics,
      wpi::units::meters_per_second_t maxVelocity)
      : m_kinematics(std::move(kinematics)), m_maxVelocity(maxVelocity) {}
 
  constexpr wpi::units::meters_per_second_t MaxVelocity(
      const Pose2d& pose, wpi::units::curvature_t curvature,
      wpi::units::meters_per_second_t velocity) const override {
    auto wheelVelocities =
        m_kinematics.ToWheelVelocities({velocity, 0_mps, velocity * curvature});
    wheelVelocities.Desaturate(m_maxVelocity);
 
    return m_kinematics.ToChassisVelocities(wheelVelocities).vx;
  }
 
  constexpr MinMax MinMaxAcceleration(
      const Pose2d& pose, wpi::units::curvature_t curvature,
      wpi::units::meters_per_second_t velocity) const override {
    return {};
  }
 
 private:
  DifferentialDriveKinematics m_kinematics;
  wpi::units::meters_per_second_t m_maxVelocity;
};
}  // namespace wpi::math