사용자 정의 인터페이스: msg·srv·action 설계와 배포

ros2 interface packages
ros2 interface package sensor_msgs
ros2 interface list | grep -E 'geometry_msgs|sensor_msgs|nav_msgs'
ros2 interface show geometry_msgs/msg/Twist
ros2 interface show sensor_msgs/msg/BatteryState

# msg/GripperCommand.msg
std_msgs/Header header
uint8 mode
float32 position
float32 max_effort
bool wait_for_contact
string operator_note

float32[] samples              # 길이 제한 없는 Sequence
float32[3] tip_offset          # 정확히 3개인 Array
int32[<=8] sensor_ids          # 최대 8개인 Bounded Sequence
string<=64 source_name         # 최대 길이가 제한된 String

uint8 MODE_OPEN=0
uint8 MODE_CLOSE=1
uint8 MODE_HOLD=2

uint8 mode MODE_HOLD
float32 speed 0.5

my_robot_interfaces/
├── CMakeLists.txt
├── package.xml
├── msg/
│   ├── GripperCommand.msg
│   └── GripperState.msg
├── srv/
│   └── SetGripperMode.srv
└── action/
    └── GraspObject.action

# Gripper가 적용할 목표 명령
uint8 MODE_OPEN=0
uint8 MODE_CLOSE=1
uint8 MODE_HOLD=2

std_msgs/Header header          # Command 생성 시각과 gripper frame
uint8 mode                      # MODE_* 중 하나
float32 position                # 0.0 닫힘 ~ 1.0 열림
float32 max_effort              # [N], 0이면 Controller 기본 제한
float32 speed                   # 0.0 ~ 1.0 정규화 속도
bool wait_for_contact
string<=64 command_id

# 측정·추정된 Gripper 상태
std_msgs/Header header
float32 position                # 0.0 ~ 1.0
float32 effort                  # [N]
bool moving
bool contact_detected
uint16 fault_code               # 0이면 Fault 없음
string<=128 fault_message

# srv/SetGripperMode.srv
uint8 MODE_OPEN=0
uint8 MODE_CLOSE=1
uint8 MODE_HOLD=2

uint8 mode
float32 max_effort              # [N]
---
bool accepted
uint16 error_code
string<=128 message

# action/GraspObject.action
# Goal
string<=64 object_id
geometry_msgs/PoseStamped target_pose
float32 max_effort              # [N]
float32 timeout                 # [s]
---
# Result
bool success
uint16 error_code
string<=128 message
my_robot_interfaces/GripperState final_state
---
# Feedback
uint8 phase
float32 progress                # 0.0 ~ 1.0
my_robot_interfaces/GripperState current_state

cd ~/ros2_ws/src
ros2 pkg create --build-type ament_cmake my_robot_interfaces
mkdir -p my_robot_interfaces/msg
mkdir -p my_robot_interfaces/srv
mkdir -p my_robot_interfaces/action

cmake_minimum_required(VERSION 3.8)
project(my_robot_interfaces)

find_package(ament_cmake REQUIRED)
find_package(rosidl_default_generators REQUIRED)
find_package(std_msgs REQUIRED)
find_package(geometry_msgs REQUIRED)

rosidl_generate_interfaces(${PROJECT_NAME}
  "msg/GripperCommand.msg"
  "msg/GripperState.msg"
  "srv/SetGripperMode.srv"
  "action/GraspObject.action"
  DEPENDENCIES
    std_msgs
    geometry_msgs
)

ament_export_dependencies(rosidl_default_runtime)
ament_package()

<?xml version="1.0"?>
<package format="3">
  <name>my_robot_interfaces</name>
  <version>0.1.0</version>
  <description>My robot public ROS 2 interfaces</description>
  <maintainer email="robot@example.com">Robot Team</maintainer>
  <license>Apache-2.0</license>

  <buildtool_depend>ament_cmake</buildtool_depend>
  <build_depend>rosidl_default_generators</build_depend>
  <exec_depend>rosidl_default_runtime</exec_depend>

  <depend>std_msgs</depend>
  <depend>geometry_msgs</depend>

  <member_of_group>rosidl_interface_packages</member_of_group>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

cd ~/ros2_ws

# Dependency 확인
rosdep install --from-paths src --ignore-src -r -y

# Interface와 의존 Package까지 Build
colcon build --packages-up-to my_robot_interfaces

# 현재 Shell에 새 Install Overlay 적용
source install/setup.bash

# 생성 결과 확인
ros2 interface package my_robot_interfaces
ros2 interface show my_robot_interfaces/msg/GripperCommand
ros2 interface show my_robot_interfaces/srv/SetGripperMode
ros2 interface show my_robot_interfaces/action/GraspObject
ros2 interface proto my_robot_interfaces/msg/GripperCommand

<depend>rclpy</depend>
<depend>my_robot_interfaces</depend>

import rclpy
from rclpy.node import Node

from my_robot_interfaces.msg import GripperCommand


class GripperCommandPublisher(Node):
    def __init__(self):
        super().__init__('gripper_command_publisher')
        self.publisher = self.create_publisher(
            GripperCommand,
            '/gripper/command',
            10,
        )
        self.timer = self.create_timer(1.0, self.publish_command)
        self.sequence = 0

    def publish_command(self):
        self.sequence += 1
        message = GripperCommand()
        message.header.stamp = self.get_clock().now().to_msg()
        message.header.frame_id = 'gripper_base'
        message.mode = GripperCommand.MODE_CLOSE
        message.position = 0.2
        message.max_effort = 15.0
        message.speed = 0.4
        message.wait_for_contact = True
        message.command_id = f'grasp-{self.sequence:04d}'
        self.publisher.publish(message)
        self.get_logger().info(f'published {message.command_id}')


def main(args=None):
    rclpy.init(args=args)
    node = GripperCommandPublisher()
    try:
        rclpy.spin(node)
    finally:
        node.destroy_node()
        rclpy.shutdown()


if __name__ == '__main__':
    main()

import math

import rclpy
from rclpy.node import Node

from my_robot_interfaces.msg import GripperCommand


class SafeGripperReceiver(Node):
    VALID_MODES = {
        GripperCommand.MODE_OPEN,
        GripperCommand.MODE_CLOSE,
        GripperCommand.MODE_HOLD,
    }

    def __init__(self):
        super().__init__('safe_gripper_receiver')
        self.subscription = self.create_subscription(
            GripperCommand,
            '/gripper/command',
            self.on_command,
            10,
        )

    def on_command(self, message):
        if message.mode not in self.VALID_MODES:
            self.get_logger().error('unknown mode; command rejected')
            return
        if not math.isfinite(message.position) or not 0.0 <= message.position <= 1.0:
            self.get_logger().error('position outside [0.0, 1.0]')
            return
        if not math.isfinite(message.max_effort) or message.max_effort < 0.0:
            self.get_logger().error('invalid max_effort')
            return
        if message.header.frame_id != 'gripper_base':
            self.get_logger().error('unexpected frame_id')
            return
        self.get_logger().info(f'accepted {message.command_id}')


def main(args=None):
    rclpy.init(args=args)
    node = SafeGripperReceiver()
    try:
        rclpy.spin(node)
    finally:
        node.destroy_node()
        rclpy.shutdown()

find_package(rclcpp REQUIRED)
find_package(my_robot_interfaces REQUIRED)

add_executable(gripper_sender src/gripper_sender.cpp)
ament_target_dependencies(gripper_sender
  rclcpp
  my_robot_interfaces
)

install(TARGETS gripper_sender
  DESTINATION lib/${PROJECT_NAME}
)

#include <chrono>
#include <memory>

#include "rclcpp/rclcpp.hpp"
#include "my_robot_interfaces/msg/gripper_command.hpp"

using namespace std::chrono_literals;

class GripperSender : public rclcpp::Node
{
public:
  GripperSender() : Node("gripper_sender")
  {
    publisher_ = create_publisher<
      my_robot_interfaces::msg::GripperCommand>("/test/gripper/command", 10);
    timer_ = create_wall_timer(1s, [this]() { publish_once(); });
  }

private:
  void publish_once()
  {
    my_robot_interfaces::msg::GripperCommand message;
    message.header.stamp = now();
    message.header.frame_id = "gripper_base";
    message.mode = my_robot_interfaces::msg::GripperCommand::MODE_HOLD;
    message.position = 0.5F;
    message.max_effort = 8.0F;
    message.speed = 0.25F;
    message.command_id = "cpp-hold";
    publisher_->publish(message);
  }

  rclcpp::Publisher<my_robot_interfaces::msg::GripperCommand>::SharedPtr publisher_;
  rclcpp::TimerBase::SharedPtr timer_;
};

int main(int argc, char ** argv)
{
  rclcpp::init(argc, argv);
  rclcpp::spin(std::make_shared<GripperSender>());
  rclcpp::shutdown();
  return 0;
}

ros2 topic pub --once /test/gripper/command \
  my_robot_interfaces/msg/GripperCommand \
  "{header: {frame_id: gripper_base}, mode: 1, position: 0.2, max_effort: 10.0, speed: 0.3, wait_for_contact: true, command_id: cli-test}"

ros2 topic echo /test/gripper/command --once
ros2 topic info /test/gripper/command --verbose

ros2 service call /test/gripper/set_mode \
  my_robot_interfaces/srv/SetGripperMode \
  "{mode: 2, max_effort: 5.0}"

ros2 action send_goal /test/gripper/grasp \
  my_robot_interfaces/action/GraspObject \
  "{object_id: box_01, max_effort: 12.0, timeout: 5.0}" \
  --feedback

colcon build --packages-up-to my_robot_interfaces
colcon test --packages-select my_robot_interfaces
colcon test-result --verbose

ros2 interface show my_robot_interfaces/msg/GripperCommand

# 어느 Package Prefix를 보고 있는가
ros2 pkg prefix my_robot_interfaces

# 현재 Overlay 순서
printenv AMENT_PREFIX_PATH | tr ':' '\n'

# 설치 산출물 확인
find install/my_robot_interfaces -maxdepth 4 -type f | sort

# 의존 관계 확인
ros2 pkg xml my_robot_interfaces
colcon list