ROS使用（5）action学习

action消息的构建

首先进行功能包的创建

mkdir -p ros2_ws/src
cd ros2_ws/src
ros2 pkg create action_tutorials_interfaces

action消息的类型

# Request
---
# Result
---
# Feedback

动作定义由三个消息定义组成，以---分隔。

• 从动作客户机向动作服务器发送请求消息以启动新目标。
• 当目标完成时，从动作服务器向动作客户端发送结果消息。
• 反馈消息周期性地从动作服务器发送到动作客户端，其中包含关于目标的更新。

创建消息

cd action_tutorials_interfaces
mkdir action

创建一个Fibonacci.action文件指定action的消息

int32 order
---
int32[] sequence
---
int32[] partial_sequence

编译消息

在我们可以在代码中使用新的Fibonacci动作类型之前，我们必须将定义传递给Rosidl代码生成管道。这可以通过在CMakeLists.txt中的ament_package（）行之前添加以下行来实现，即action_tutorials_interfaces中的行：

CMAkeLists.txt文件进行修改

find_package(rosidl_default_generators REQUIRED)rosidl_generate_interfaces(${PROJECT_NAME}"action/Fibonacci.action"
)

xml文件进行修改

<buildtool_depend>rosidl_default_generators</buildtool_depend><depend>action_msgs</depend><member_of_group>rosidl_interface_packages</member_of_group>

在这里action文件就算是生成了

action_server进行使用

进行action使用的功能包的创建

os2 pkg create --dependencies action_tutorials_interfaces rclcpp rclcpp_action rclcpp_components -- action_tutorials_cpp

action_tutorials_interfaces rclcpp rclcpp_action rclcpp_components为该功能包的相关依赖

windows编译

为了使软件包能够在Windows上编译和工作，我们需要添加一些“可见性控制”。有关详细信息，请参见Windows提示和技巧文档中的Windows符号可见性。
打开action_tutorials_cpp/include/action_tutorials_cpp/visibility_control.h，并将以下代码放入：

#ifndef ACTION_TUTORIALS_CPP__VISIBILITY_CONTROL_H_
#define ACTION_TUTORIALS_CPP__VISIBILITY_CONTROL_H_#ifdef __cplusplus
extern "C"
{
#endif// This logic was borrowed (then namespaced) from the examples on the gcc wiki:
//     https://gcc.gnu.org/wiki/Visibility#if defined _WIN32 || defined __CYGWIN__#ifdef __GNUC__#define ACTION_TUTORIALS_CPP_EXPORT __attribute__ ((dllexport))#define ACTION_TUTORIALS_CPP_IMPORT __attribute__ ((dllimport))#else#define ACTION_TUTORIALS_CPP_EXPORT __declspec(dllexport)#define ACTION_TUTORIALS_CPP_IMPORT __declspec(dllimport)#endif#ifdef ACTION_TUTORIALS_CPP_BUILDING_DLL#define ACTION_TUTORIALS_CPP_PUBLIC ACTION_TUTORIALS_CPP_EXPORT#else#define ACTION_TUTORIALS_CPP_PUBLIC ACTION_TUTORIALS_CPP_IMPORT#endif#define ACTION_TUTORIALS_CPP_PUBLIC_TYPE ACTION_TUTORIALS_CPP_PUBLIC#define ACTION_TUTORIALS_CPP_LOCAL
#else#define ACTION_TUTORIALS_CPP_EXPORT __attribute__ ((visibility("default")))#define ACTION_TUTORIALS_CPP_IMPORT#if __GNUC__ >= 4#define ACTION_TUTORIALS_CPP_PUBLIC __attribute__ ((visibility("default")))#define ACTION_TUTORIALS_CPP_LOCAL  __attribute__ ((visibility("hidden")))#else#define ACTION_TUTORIALS_CPP_PUBLIC#define ACTION_TUTORIALS_CPP_LOCAL#endif#define ACTION_TUTORIALS_CPP_PUBLIC_TYPE
#endif#ifdef __cplusplus
}
#endif#endif  // ACTION_TUTORIALS_CPP__VISIBILITY_CONTROL_H_

创建server文件

#include <functional>
#include <memory>
#include <thread>#include "action_tutorials_interfaces/action/fibonacci.hpp"
#include "rclcpp/rclcpp.hpp"
#include "rclcpp_action/rclcpp_action.hpp"
#include "rclcpp_components/register_node_macro.hpp"#include "action_tutorials_cpp/visibility_control.h"namespace action_tutorials_cpp
{// 进行节点的创建
class FibonacciActionServer : public rclcpp::Node
{
public:// 声明数据类型using Fibonacci = action_tutorials_interfaces::action::Fibonacci;using GoalHandleFibonacci = rclcpp_action::ServerGoalHandle<Fibonacci>;ACTION_TUTORIALS_CPP_PUBLICexplicit FibonacciActionServer(const rclcpp::NodeOptions & options = rclcpp::NodeOptions()): Node("fibonacci_action_server", options){using namespace std::placeholders;// 创建对应的服务this->action_server_ = rclcpp_action::create_server<Fibonacci>(this,"fibonacci",// 用于处理目标的回调函数std::bind(&FibonacciActionServer::handle_goal, this, _1, _2),// 用于处理取消的回调函数std::bind(&FibonacciActionServer::handle_cancel, this, _1),// 用于处理目标接受的回调函数std::bind(&FibonacciActionServer::handle_accepted, this, _1));}private:rclcpp_action::Server<Fibonacci>::SharedPtr action_server_;rclcpp_action::GoalResponse handle_goal(const rclcpp_action::GoalUUID & uuid,std::shared_ptr<const Fibonacci::Goal> goal){RCLCPP_INFO(this->get_logger(), "Received goal request with order %d", goal->order);(void)uuid;return rclcpp_action::GoalResponse::ACCEPT_AND_EXECUTE;}rclcpp_action::CancelResponse handle_cancel(const std::shared_ptr<GoalHandleFibonacci> goal_handle){RCLCPP_INFO(this->get_logger(), "Received request to cancel goal");(void)goal_handle;return rclcpp_action::CancelResponse::ACCEPT;}void handle_accepted(const std::shared_ptr<GoalHandleFibonacci> goal_handle){using namespace std::placeholders;// this needs to return quickly to avoid blocking the executor, so spin up a new threadstd::thread{std::bind(&FibonacciActionServer::execute, this, _1), goal_handle}.detach();}void execute(const std::shared_ptr<GoalHandleFibonacci> goal_handle){RCLCPP_INFO(this->get_logger(), "Executing goal");rclcpp::Rate loop_rate(1);const auto goal = goal_handle->get_goal();auto feedback = std::make_shared<Fibonacci::Feedback>();auto & sequence = feedback->partial_sequence;sequence.push_back(0);sequence.push_back(1);auto result = std::make_shared<Fibonacci::Result>();for (int i = 1; (i < goal->order) && rclcpp::ok(); ++i) {// Check if there is a cancel requestif (goal_handle->is_canceling()) {result->sequence = sequence;goal_handle->canceled(result);RCLCPP_INFO(this->get_logger(), "Goal canceled");return;}// Update sequencesequence.push_back(sequence[i] + sequence[i - 1]);// Publish feedbackgoal_handle->publish_feedback(feedback);RCLCPP_INFO(this->get_logger(), "Publish feedback");loop_rate.sleep();}// Check if goal is doneif (rclcpp::ok()) {result->sequence = sequence;goal_handle->succeed(result);RCLCPP_INFO(this->get_logger(), "Goal succeeded");}}
};  // class FibonacciActionServer}  // namespace action_tutorials_cppRCLCPP_COMPONENTS_REGISTER_NODE(action_tutorials_cpp::FibonacciActionServer)

几个关键的数据类型

ClientGoalHandle：

用于与客户端发送过来的目标进行交互。可以使用此类检查目标的状态和结果，这个类不是通过用户创建的，而是在目标进行接受。

// 使用这个类去检查goal 的状态和这个结果，并不意味着被用户创建，当一个用户的goal被接受的时候才能被创建
template<typename ActionT>
class ServerGoalHandle : public ServerGoalHandleBase
{
public:
//   发送一个更新数据，处理真个进行关于goal目标的
//  这个函数只能当goal被调用的时候才能被调用
// voidpublish_feedback(std::shared_ptr<typename ActionT::Feedback> feedback_msg){auto feedback_message = std::make_shared<typename ActionT::Impl::FeedbackMessage>();feedback_message->goal_id.uuid = uuid_;feedback_message->feedback = *feedback_msg;publish_feedback_(feedback_message);}
// 当goal无法达到，并且已中止。
// 只有当goal正在执行但无法完成时才调用此函数。
// 这是一个终端状态，在这之后不应该再对目标句柄调用任何方法
// param[in]result_msg要发送给客户端的最终结果。voidabort(typename ActionT::Result::SharedPtr result_msg){_abort();auto response = std::make_shared<typename ActionT::Impl::GetResultService::Response>();response->status = action_msgs::msg::GoalStatus::STATUS_ABORTED;response->result = *result_msg;on_terminal_state_(uuid_, response);}/// 当这个goal执行成功的时候执行
//  param[in] result_msg the final result to send to clients.voidsucceed(typename ActionT::Result::SharedPtr result_msg){_succeed();auto response = std::make_shared<typename ActionT::Impl::GetResultService::Response>();response->status = action_msgs::msg::GoalStatus::STATUS_SUCCEEDED;response->result = *result_msg;on_terminal_state_(uuid_, response);}/// Indicate that a goal has been canceled./*** Only call this if the goal is executing or pending, but has been canceled.* This is a terminal state, no more methods should be called on a goal handle after this is* called.* \throws rclcpp::exceptions::RCLError If the goal is in any state besides executing.** \param[in] result_msg the final result to send to clients.*/voidcanceled(typename ActionT::Result::SharedPtr result_msg){_canceled();auto response = std::make_shared<typename ActionT::Impl::GetResultService::Response>();response->status = action_msgs::msg::GoalStatus::STATUS_CANCELED;response->result = *result_msg;on_terminal_state_(uuid_, response);}/// Indicate that the server is starting to execute a goal.
//  throws rclcpp::exceptions::RCLError If the goal is in any state besides executing.voidexecute(){_execute();on_executing_(uuid_);}/// Get the user provided message describing the goal.const std::shared_ptr<const typename ActionT::Goal>get_goal() const{return goal_;}/// Get the unique identifier of the goalconst GoalUUID &get_goal_id() const{return uuid_;}virtual ~ServerGoalHandle(){// Cancel goal if handle was allowed to destruct without reaching a terminal stateif (try_canceling()) {auto null_result = std::make_shared<typename ActionT::Impl::GetResultService::Response>();null_result->status = action_msgs::msg::GoalStatus::STATUS_CANCELED;on_terminal_state_(uuid_, null_result);}}protected:/// \internalServerGoalHandle(std::shared_ptr<rcl_action_goal_handle_t> rcl_handle,GoalUUID uuid,std::shared_ptr<const typename ActionT::Goal> goal,std::function<void(const GoalUUID &, std::shared_ptr<void>)> on_terminal_state,std::function<void(const GoalUUID &)> on_executing,std::function<void(std::shared_ptr<typename ActionT::Impl::FeedbackMessage>)> publish_feedback): ServerGoalHandleBase(rcl_handle), goal_(goal), uuid_(uuid),on_terminal_state_(on_terminal_state), on_executing_(on_executing),publish_feedback_(publish_feedback){}/// The user provided message describing the goal.const std::shared_ptr<const typename ActionT::Goal> goal_;/// A unique id for the goal request.const GoalUUID uuid_;friend Server<ActionT>;std::function<void(const GoalUUID &, std::shared_ptr<void>)> on_terminal_state_;std::function<void(const GoalUUID &)> on_executing_;std::function<void(std::shared_ptr<typename ActionT::Impl::FeedbackMessage>)> publish_feedback_;
};

/// A response returned by an action server callback when a goal is requested.
enum class GoalResponse : int8_t
{/// The goal is rejected and will not be executed.REJECT = 1,/// The server accepts the goal, and is going to begin execution immediately.ACCEPT_AND_EXECUTE = 2,/// The server accepts the goal, and is going to execute it later.ACCEPT_AND_DEFER = 3,
};/// A response returned by an action server callback when a goal has been asked to be canceled.
enum class CancelResponse : int8_t
{/// The server will not try to cancel the goal.REJECT = 1,/// The server has agreed to try to cancel the goal.ACCEPT = 2,
};

action client定义

#include <functional>
#include <future>
#include <memory>
#include <string>
#include <sstream>#include "action_tutorials_interfaces/action/fibonacci.hpp"#include "rclcpp/rclcpp.hpp"
#include "rclcpp_action/rclcpp_action.hpp"
#include "rclcpp_components/register_node_macro.hpp"namespace action_tutorials_cpp
{
class FibonacciActionClient : public rclcpp::Node
{
public:using Fibonacci = action_tutorials_interfaces::action::Fibonacci;using GoalHandleFibonacci = rclcpp_action::ClientGoalHandle<Fibonacci>;explicit FibonacciActionClient(const rclcpp::NodeOptions & options): Node("fibonacci_action_client", options){this->client_ptr_ = rclcpp_action::create_client<Fibonacci>(this,"fibonacci");this->timer_ = this->create_wall_timer(std::chrono::milliseconds(500),std::bind(&FibonacciActionClient::send_goal, this));}void send_goal(){using namespace std::placeholders;this->timer_->cancel();if (!this->client_ptr_->wait_for_action_server()) {RCLCPP_ERROR(this->get_logger(), "Action server not available after waiting");rclcpp::shutdown();}auto goal_msg = Fibonacci::Goal();goal_msg.order = 10;RCLCPP_INFO(this->get_logger(), "Sending goal");auto send_goal_options = rclcpp_action::Client<Fibonacci>::SendGoalOptions();send_goal_options.goal_response_callback =std::bind(&FibonacciActionClient::goal_response_callback, this, _1);send_goal_options.feedback_callback =std::bind(&FibonacciActionClient::feedback_callback, this, _1, _2);send_goal_options.result_callback =std::bind(&FibonacciActionClient::result_callback, this, _1);this->client_ptr_->async_send_goal(goal_msg, send_goal_options);}private:rclcpp_action::Client<Fibonacci>::SharedPtr client_ptr_;rclcpp::TimerBase::SharedPtr timer_;void goal_response_callback(std::shared_future<GoalHandleFibonacci::SharedPtr> future){auto goal_handle = future.get();if (!goal_handle) {RCLCPP_ERROR(this->get_logger(), "Goal was rejected by server");} else {RCLCPP_INFO(this->get_logger(), "Goal accepted by server, waiting for result");}}void feedback_callback(GoalHandleFibonacci::SharedPtr,const std::shared_ptr<const Fibonacci::Feedback> feedback){std::stringstream ss;ss << "Next number in sequence received: ";for (auto number : feedback->partial_sequence) {ss << number << " ";}RCLCPP_INFO(this->get_logger(), ss.str().c_str());}void result_callback(const GoalHandleFibonacci::WrappedResult & result){switch (result.code) {case rclcpp_action::ResultCode::SUCCEEDED:break;case rclcpp_action::ResultCode::ABORTED:RCLCPP_ERROR(this->get_logger(), "Goal was aborted");return;case rclcpp_action::ResultCode::CANCELED:RCLCPP_ERROR(this->get_logger(), "Goal was canceled");return;default:RCLCPP_ERROR(this->get_logger(), "Unknown result code");return;}std::stringstream ss;ss << "Result received: ";for (auto number : result.result->sequence) {ss << number << " ";}RCLCPP_INFO(this->get_logger(), ss.str().c_str());rclcpp::shutdown();}
};  // class FibonacciActionClient}  // namespace action_tutorials_cppRCLCPP_COMPONENTS_REGISTER_NODE(action_tutorials_cpp::FibonacciActionClient)

配置对应的CMakeLists.txt文件

add_library(action_server SHAREDsrc/fibonacci_action_server.cpp)
target_include_directories(action_server PRIVATE$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>$<INSTALL_INTERFACE:include>)
target_compile_definitions(action_serverPRIVATE "ACTION_TUTORIALS_CPP_BUILDING_DLL")
ament_target_dependencies(action_server"action_tutorials_interfaces""rclcpp""rclcpp_action""rclcpp_components")
rclcpp_components_register_node(action_server PLUGIN "action_tutorials_cpp::FibonacciActionServer" EXECUTABLE fibonacci_action_server)
install(TARGETSaction_serverARCHIVE DESTINATION libLIBRARY DESTINATION libRUNTIME DESTINATION bin)add_library(action_client SHAREDsrc/fibonacci_action_client.cpp)
target_include_directories(action_client PRIVATE$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>$<INSTALL_INTERFACE:include>)
target_compile_definitions(action_clientPRIVATE "ACTION_TUTORIALS_CPP_BUILDING_DLL")
ament_target_dependencies(action_client"action_tutorials_interfaces""rclcpp""rclcpp_action""rclcpp_components")
rclcpp_components_register_node(action_client PLUGIN "action_tutorials_cpp::FibonacciActionClient" EXECUTABLE fibonacci_action_client)
install(TARGETSaction_clientARCHIVE DESTINATION libLIBRARY DESTINATION libRUNTIME DESTINATION bin)

通过编译之后就可以得到对应的模型