ros2 自定义消息、服务、动作接口详细范例

在ROS2中，自定义消息（.msg）、服务（.srv）和动作（.action）接口是扩展系统功能的核心。以下以完整工程结构为例，详细说明定义、编译和使用的全流程：

1. 项目结构

bash 复制代码

custom_interfaces/
├── CMakeLists.txt
├── package.xml
├── msg/
│   ├── MyMessage.msg
│   └── ...
├── srv/
│   ├── MyService.srv
│   └── ...
└── action/
    ├── MyAction.action
    └── ...

user_pkg/  # 使用自定义接口的包
├── CMakeLists.txt
├── package.xml
├── src/
│   ├── publisher_node.cpp
│   ├── subscriber_node.cpp
│   ├── service_server.cpp
│   ├── service_client.cpp
│   ├── action_server.cpp
│   └── action_client.cpp
└── ...

2. 自定义接口定义

消息（.msg）

custom_interfaces/msg/MyMessage.msg:

plaintext 复制代码

int32 id
string data
float64[3] values

服务（.srv）

custom_interfaces/srv/MyService.srv:

plaintext 复制代码

# 请求部分
string query
---
# 响应部分
bool success
string result

动作（.action）

custom_interfaces/action/MyAction.action:

plaintext 复制代码

# 目标（Goal）
int32 target_value
---
# 结果（Result）
bool achieved
float64 final_position
---
# 反馈（Feedback）
float64 progress

3. 编译配置（custom_interfaces包）

CMakeLists.txt关键部分:

cmake 复制代码

cmake_minimum_required(VERSION 3.8)
project(custom_interfaces)

find_package(ament_cmake REQUIRED)
find_package(rosidl_default_generators REQUIRED)

# 添加消息、服务、动作文件
rosidl_generate_interfaces(${PROJECT_NAME}
  "msg/MyMessage.msg"
  "srv/MyService.srv"
  "action/MyAction.action"
  DEPENDENCIES std_msgs
)

ament_package()

package.xml关键依赖:

xml 复制代码

<build_depend>rosidl_default_generators</build_depend>
<exec_depend>rosidl_default_runtime</exec_depend>
<member_of_group>rosidl_interface_packages</member_of_group>

4. 使用自定义接口（user_pkg包）

消息发布/订阅示例

发布者节点（publisher_node.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/msg/my_message.hpp"

int main(int argc, char **argv) {
  rclcpp::init(argc, argv);
  auto node = rclcpp::Node::make_shared("msg_publisher");
  auto pub = node->create_publisher<custom_interfaces::msg::MyMessage>("my_topic", 10);

  auto msg = custom_interfaces::msg::MyMessage();
  msg.id = 1;
  msg.data = "Hello ROS2";
  msg.values = {1.0, 2.0, 3.0};

  rclcpp::Rate loop_rate(1);
  while (rclcpp::ok()) {
    pub->publish(msg);
    loop_rate.sleep();
  }
  rclcpp::shutdown();
  return 0;
}

订阅者节点（subscriber_node.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/msg/my_message.hpp"

void topic_callback(const custom_interfaces::msg::MyMessage &msg) {
  RCLCPP_INFO(rclcpp::get_logger("Subscriber"), "Received: ID=%d, Data=%s", msg.id, msg.data.c_str());
}

int main(int argc, char **argv) {
  rclcpp::init(argc, argv);
  auto node = rclcpp::Node::make_shared("msg_subscriber");
  auto sub = node->create_subscription<custom_interfaces::msg::MyMessage>(
    "my_topic", 10, topic_callback);
  rclcpp::spin(node);
  rclcpp::shutdown();
  return 0;
}

服务调用示例

服务端（service_server.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/srv/my_service.hpp"

void handle_service(
  const std::shared_ptr<rmw_request_id_t> request_header,
  const std::shared_ptr<custom_interfaces::srv::MyService::Request> req,
  const std::shared_ptr<custom_interfaces::srv::MyService::Response> res
) {
  res->success = (req->query == "valid");
  res->result = "Processed: " + req->query;
}

int main(int argc, char **argv) {
  rclcpp::init(argc, argv);
  auto node = rclcpp::Node::make_shared("srv_server");
  node->create_service<custom_interfaces::srv::MyService>(
    "my_service", handle_service);
  rclcpp::spin(node);
  rclcpp::shutdown();
  return 0;
}

客户端（service_client.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/srv/my_service.hpp"

int main(int argc, char **argv) {
  rclcpp::init(argc, argv);
  auto node = rclcpp::Node::make_shared("srv_client");
  auto client = node->create_client<custom_interfaces::srv::MyService>("my_service");

  auto request = std::make_shared<custom_interfaces::srv::MyService::Request>();
  request->query = "test_query";

  while (!client->wait_for_service(std::chrono::seconds(1))) {
    RCLCPP_WARN(node->get_logger(), "Service unavailable");
  }

  auto result = client->async_send_request(request);
  if (rclcpp::spin_until_future_complete(node, result) == 
      rclcpp::FutureReturnCode::SUCCESS) {
    RCLCPP_INFO(node->get_logger(), "Result: %s", result.get()->result.c_str());
  }
  rclcpp::shutdown();
  return 0;
}

动作调用示例

动作服务器（action_server.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/action/my_action.hpp"
#include "rclcpp_action/rclcpp_action.hpp"

class ActionServer : public rclcpp::Node {
public:
  using MyAction = custom_interfaces::action::MyAction;
  explicit ActionServer() : Node("action_server") {
    action_server_ = rclcpp_action::create_server<MyAction>(
      this, "my_action",
      [this](const std::shared_ptr<Goal> goal) {
        RCLCPP_INFO(this->get_logger(), "Received goal: %d", goal->target_value);
        return rclcpp_action::GoalResponse::ACCEPT_AND_EXECUTE;
      },
      [this](const std::shared_ptr<Goal> goal) {
        // 取消逻辑
        return rclcpp_action::CancelResponse::ACCEPT;
      },
      [this](const std::shared_ptr<Goal> goal, const std::shared_ptr<Feedback> feedback) {
        feedback->progress = 0.5; // 更新反馈
      },
      [this](const std::shared_ptr<Goal> goal, const std::shared_ptr<Result> result) {
        result->achieved = true;
        result->final_position = 10.0;
        return rclcpp_action::ResultCode::SUCCEEDED;
      }
    );
  }
private:
  rclcpp_action::Server<MyAction>::SharedPtr action_server_;
};

动作客户端（action_client.cpp）:

cpp 复制代码

#include "rclcpp/rclcpp.hpp"
#include "custom_interfaces/action/my_action.hpp"
#include "rclcpp_action/rclcpp_action.hpp"

class ActionClient : public rclcpp::Node {
public:
  using MyAction = custom_interfaces::action::MyAction;
  explicit ActionClient() : Node("action_client") {
    action_client_ = rclcpp_action::create_client<MyAction>(this, "my_action");
    auto goal = MyAction::Goal();
    goal.target_value = 100;

    action_client_->async_send_goal(goal, 
      [this](auto future) {
        auto result = future.get();
        if (!result) {
          RCLCPP_ERROR(this->get_logger(), "Goal failed");
        } else if (result->code == rclcpp_action::ResultCode::SUCCEEDED) {
          RCLCPP_INFO(this->get_logger(), "Success! Final position: %f", result->result->final_position);
        }
      }
    );
  }
private:
  rclcpp_action::Client<MyAction>::SharedPtr action_client_;
};

5. 编译与运行

编译自定义接口包:

bash 复制代码

cd ~/ros2_ws
colcon build --packages-select custom_interfaces
source install/setup.bash

编译用户包:

bash 复制代码

colcon build --packages-select user_pkg
source install/setup.bash

运行示例:

bash 复制代码

# 消息测试
ros2 run user_pkg publisher_node
ros2 run user_pkg subscriber_node

# 服务测试
ros2 run user_pkg service_server
ros2 run user_pkg service_client

# 动作测试
ros2 run user_pkg action_server
ros2 run user_pkg action_client

6. 验证接口生成

bash 复制代码

# 检查消息类型
ros2 interface show custom_interfaces/msg/MyMessage

# 检查服务类型
ros2 interface show custom_interfaces/srv/MyService

# 检查动作类型
ros2 interface show custom_interfaces/action/MyAction

关键注意事项

依赖管理 ：确保package.xml中声明<build_depend>和<exec_depend>，并在CMakeLists.txt中链接rosidl_default_runtime。
命名规范 ：接口名称需使用小写+下划线 （如my_message），避免大写开头。
编译顺序 ：先编译custom_interfaces包，再编译使用它的包。
调试工具 ：使用rqt_graph查看节点/话题连接，ros2 topic echo验证数据。

通过以上步骤，您可完整实现ROS2中自定义消息、服务和动作接口的定义、编译与使用。实际开发中，可根据需求扩展接口字段和业务逻辑。