Aynı robot, iki dünya

# ros2_control'ü önce hazır örnekte gör (mock donanım)
sudo apt install -y ros-jazzy-ros2-control ros-jazzy-ros2-controllers ros-jazzy-ros2-control-demos
ros2 launch ros2_control_demo_example_2 diffbot.launch.py
ros2 control list_controllers          # diffbot_base_controller active
ros2 control list_hardware_interfaces  # left_wheel_joint/velocity [claimed]
ros2 topic pub --rate 10 /diffbot_base_controller/cmd_vel geometry_msgs/msg/TwistStamped \
  "{twist: {linear: {x: 0.3}, angular: {z: 0.5}}}"

<!-- urdf/rover.ros2_control.xacro — aynı controller, üç farklı donanım -->
<robot xmlns:xacro="http://www.ros.org/wiki/xacro">
  <xacro:arg name="hw" default="mock"/>   <!-- mock | gazebo | real -->
  <ros2_control name="RoverSystem" type="system">
    <hardware>
      <xacro:if value="${'$(arg hw)' == 'gazebo'}">
        <plugin>gz_ros2_control/GazeboSimSystem</plugin>
      </xacro:if>
      <xacro:if value="${'$(arg hw)' == 'mock'}">
        <plugin>mock_components/GenericSystem</plugin>
        <param name="calculate_dynamics">true</param>
      </xacro:if>
      <xacro:if value="${'$(arg hw)' == 'real'}">
        <plugin>rover_hardware/RoverSystem</plugin>
        <param name="device">/dev/ttyUSB0</param>
        <param name="baud">115200</param>
        <param name="ticks_per_rev">1400</param>
      </xacro:if>
    </hardware>
    <joint name="left_wheel_joint">
      <command_interface name="velocity"><param name="min">-30</param><param name="max">30</param></command_interface>
      <state_interface name="position"/>
      <state_interface name="velocity"/>
    </joint>
    <joint name="right_wheel_joint">
      <command_interface name="velocity"><param name="min">-30</param><param name="max">30</param></command_interface>
      <state_interface name="position"/>
      <state_interface name="velocity"/>
    </joint>
  </ros2_control>

  <xacro:if value="${'$(arg hw)' == 'gazebo'}">
    <gazebo>
      <plugin filename="gz_ros2_control-system" name="gz_ros2_control::GazeboSimROS2ControlPlugin">
        <parameters>$(find rover_bringup)/config/controllers.yaml</parameters>
      </plugin>
    </gazebo>
  </xacro:if>
</robot>

// rover_hardware/include/rover_hardware/rover_system.hpp
#pragma once
#include <hardware_interface/system_interface.hpp>
#include <hardware_interface/types/hardware_interface_return_values.hpp>
#include <rclcpp/rclcpp.hpp>
#include <string>
#include <vector>

namespace rover_hardware {

class RoverSystem : public hardware_interface::SystemInterface {
 public:
  RCLCPP_SHARED_PTR_DEFINITIONS(RoverSystem)

  CallbackReturn on_init(const hardware_interface::HardwareInfo& info) override;
  CallbackReturn on_activate(const rclcpp_lifecycle::State&) override;
  CallbackReturn on_deactivate(const rclcpp_lifecycle::State&) override;
  std::vector<hardware_interface::StateInterface> export_state_interfaces() override;
  std::vector<hardware_interface::CommandInterface> export_command_interfaces() override;
  hardware_interface::return_type read(const rclcpp::Time&, const rclcpp::Duration&) override;
  hardware_interface::return_type write(const rclcpp::Time&, const rclcpp::Duration&) override;

 private:
  bool openPort();
  void closePort();

  std::string device_;
  int baud_ = 115200;
  double ticksPerRev_ = 1400;
  int fd_ = -1;
  std::string rx_;                       // satır biriktirme tamponu
  int32_t lastTicks_[2] = {0, 0};
  bool haveTicks_ = false;
  // ros2_control bu dizilere pointer tutar: boyutları on_init'te sabitlenir
  std::vector<double> pos_, vel_, cmd_;
};

}  // namespace rover_hardware

# MuJoCo ile aynı ros2_control (Jazzy için paket var)
sudo apt install -y ros-jazzy-mujoco-ros2-control ros-jazzy-mujoco-ros2-control-demos
ros2 launch mujoco_ros2_control_demos 01_basic_robot.launch.py
# Kendi robotun için: ros2_control etiketinde plugin
#   mujoco_ros2_control/MujocoSystemInterface
# ve param mujoco_model → MJCF sahne dosyan (ya da URDF'ten çalışma anında üretilen MJCF).