行动（action）比服务更为灵活和复杂。在给出行动具体说明之前，先简要复习一下：
主题-服务-行动：
场合
具体细节
服务/行动对比
从上面可以非常明显的看出，服务和行动的差异。
那么实践任务如下：
- 用行动实现第8讲中，第三种服务的功能，单目标点多参数；
行动实践1
- 用行动实现mobot在室内环境各房间的巡逻，多目标点多参数；
行动实践2
- 用行动实现mobot在室外跑道的巡逻，多目标点多参数不确定。
行动实践3-日光
行动实践3-灯光
由此，需要融合OpenAI，OpenCV和BT。从机器人主题，服务过渡到行为。
然而行为的组合，不同状态行为的切换，构成了新的挑战，进一步学习：
- 行为树 Behavior Trees C++
- 安装：sudo apt install ros-dashing-behaviortree-cpp
- 文档：https://www.behaviortree.dev/
- 源码：https://github.com/BehaviorTree/BehaviorTree.CPP/tree/ros2-devel
熟练掌握相应算法进一步可扩展：
- 物流机器人（点点轨迹，任务调度）
- 清扫机器人（区域覆盖，协作协同）
行为（action）基础复习：
斐波那契数列与黄金分割
行为服务器端：
- 非推荐，ros1代码风格
#include <inttypes.h>
#include <memory>
#include "example_interfaces/action/fibonacci.hpp"
#include "rclcpp/rclcpp.hpp"
// TODO(jacobperron): Remove this once it is included as part of 'rclcpp.hpp'
#include "rclcpp_action/rclcpp_action.hpp"
using Fibonacci = example_interfaces::action::Fibonacci;
using GoalHandleFibonacci = rclcpp_action::ServerGoalHandle<Fibonacci>;
rclcpp_action::GoalResponse handle_goal(
const rclcpp_action::GoalUUID & uuid, std::shared_ptr<const Fibonacci::Goal> goal)
{
RCLCPP_INFO(rclcpp::get_logger("server"), "Got goal request with order %d", goal->order);
(void)uuid;
// Let's reject sequences that are over 9000
if (goal->order > 9000) {
return rclcpp_action::GoalResponse::REJECT;
}
return rclcpp_action::GoalResponse::ACCEPT_AND_EXECUTE;
}
rclcpp_action::CancelResponse handle_cancel(
const std::shared_ptr<GoalHandleFibonacci> goal_handle)
{
RCLCPP_INFO(rclcpp::get_logger("server"), "Got request to cancel goal");
(void)goal_handle;
return rclcpp_action::CancelResponse::ACCEPT;
}
void execute(
const std::shared_ptr<GoalHandleFibonacci> goal_handle)
{
RCLCPP_INFO(rclcpp::get_logger("server"), "Executing goal");
rclcpp::Rate loop_rate(1);
const auto goal = goal_handle->get_goal();
auto feedback = std::make_shared<Fibonacci::Feedback>();
auto & sequence = feedback->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 request
if (goal_handle->is_canceling()) {
result->sequence = sequence;
goal_handle->canceled(result);
RCLCPP_INFO(rclcpp::get_logger("server"), "Goal Canceled");
return;
}
// Update sequence
sequence.push_back(sequence[i] + sequence[i - 1]);
// Publish feedback
goal_handle->publish_feedback(feedback);
RCLCPP_INFO(rclcpp::get_logger("server"), "Publish Feedback");
loop_rate.sleep();
}
// Check if goal is done
if (rclcpp::ok()) {
result->sequence = sequence;
goal_handle->succeed(result);
RCLCPP_INFO(rclcpp::get_logger("server"), "Goal Succeeded");
}
}
void handle_accepted(const std::shared_ptr<GoalHandleFibonacci> goal_handle)
{
// this needs to return quickly to avoid blocking the executor, so spin up a new thread
std::thread{execute, goal_handle}.detach();
}
int main(int argc, char ** argv)
{
rclcpp::init(argc, argv);
auto node = rclcpp::Node::make_shared("minimal_action_server");
// Create an action server with three callbacks
// 'handle_goal' and 'handle_cancel' are called by the Executor (rclcpp::spin)
// 'execute' is called whenever 'handle_goal' returns by accepting a goal
// Calls to 'execute' are made in an available thread from a pool of four.
auto action_server = rclcpp_action::create_server<Fibonacci>(
node,
"fibonacci",
handle_goal,
handle_cancel,
handle_accepted);
rclcpp::spin(node);
rclcpp::shutdown();
return 0;
}
- 推荐，ros2新风格
#include <inttypes.h>
#include <memory>
#include "example_interfaces/action/fibonacci.hpp"
#include "rclcpp/rclcpp.hpp"
// TODO(jacobperron): Remove this once it is included as part of 'rclcpp.hpp'
#include "rclcpp_action/rclcpp_action.hpp"
class MinimalActionServer : public rclcpp::Node
{
public:
using Fibonacci = example_interfaces::action::Fibonacci;
using GoalHandleFibonacci = rclcpp_action::ServerGoalHandle<Fibonacci>;
explicit MinimalActionServer(const rclcpp::NodeOptions & options = rclcpp::NodeOptions())
: Node("minimal_action_server", options)
{
using namespace std::placeholders;
this->action_server_ = rclcpp_action::create_server<Fibonacci>(
this->get_node_base_interface(),
this->get_node_clock_interface(),
this->get_node_logging_interface(),
this->get_node_waitables_interface(),
"fibonacci",
std::bind(&MinimalActionServer::handle_goal, this, _1, _2),
std::bind(&MinimalActionServer::handle_cancel, this, _1),
std::bind(&MinimalActionServer::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;
// Let's reject sequences that are over 9000
if (goal->order > 9000) {
return rclcpp_action::GoalResponse::REJECT;
}
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 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->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 request
if (goal_handle->is_canceling()) {
result->sequence = sequence;
goal_handle->canceled(result);
RCLCPP_INFO(this->get_logger(), "Goal Canceled");
return;
}
// Update sequence
sequence.push_back(sequence[i] + sequence[i - 1]);
// Publish feedback
goal_handle->publish_feedback(feedback);
RCLCPP_INFO(this->get_logger(), "Publish Feedback");
loop_rate.sleep();
}
// Check if goal is done
if (rclcpp::ok()) {
result->sequence = sequence;
goal_handle->succeed(result);
RCLCPP_INFO(this->get_logger(), "Goal Suceeded");
}
}
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 thread
std::thread{std::bind(&MinimalActionServer::execute, this, _1), goal_handle}.detach();
}
}; // class MinimalActionServer
int main(int argc, char ** argv)
{
rclcpp::init(argc, argv);
auto action_server = std::make_shared<MinimalActionServer>();
rclcpp::spin(action_server);
rclcpp::shutdown();
return 0;
}
行为客户端：
- 非推荐，ros1风格
#include <inttypes.h>
#include <memory>
#include "example_interfaces/action/fibonacci.hpp"
#include "rclcpp/rclcpp.hpp"
// TODO(jacobperron): Remove this once it is included as part of 'rclcpp.hpp'
#include "rclcpp_action/rclcpp_action.hpp"
using Fibonacci = example_interfaces::action::Fibonacci;
int main(int argc, char ** argv)
{
rclcpp::init(argc, argv);
auto node = rclcpp::Node::make_shared("minimal_action_client");
auto action_client = rclcpp_action::create_client<Fibonacci>(node, "fibonacci");
if (!action_client->wait_for_action_server(std::chrono::seconds(20))) {
RCLCPP_ERROR(node->get_logger(), "Action server not available after waiting");
return 1;
}
// Populate a goal
auto goal_msg = Fibonacci::Goal();
goal_msg.order = 10;
RCLCPP_INFO(node->get_logger(), "Sending goal");
// Ask server to achieve some goal and wait until it's accepted
auto goal_handle_future = action_client->async_send_goal(goal_msg);
if (rclcpp::spin_until_future_complete(node, goal_handle_future) !=
rclcpp::executor::FutureReturnCode::SUCCESS)
{
RCLCPP_ERROR(node->get_logger(), "send goal call failed :(");
return 1;
}
rclcpp_action::ClientGoalHandle<Fibonacci>::SharedPtr goal_handle = goal_handle_future.get();
if (!goal_handle) {
RCLCPP_ERROR(node->get_logger(), "Goal was rejected by server");
return 1;
}
// Wait for the server to be done with the goal
auto result_future = goal_handle->async_result();
RCLCPP_INFO(node->get_logger(), "Waiting for result");
if (rclcpp::spin_until_future_complete(node, result_future) !=
rclcpp::executor::FutureReturnCode::SUCCESS)
{
RCLCPP_ERROR(node->get_logger(), "get result call failed :(");
return 1;
}
rclcpp_action::ClientGoalHandle<Fibonacci>::WrappedResult wrapped_result = result_future.get();
switch (wrapped_result.code) {
case rclcpp_action::ResultCode::SUCCEEDED:
break;
case rclcpp_action::ResultCode::ABORTED:
RCLCPP_ERROR(node->get_logger(), "Goal was aborted");
return 1;
case rclcpp_action::ResultCode::CANCELED:
RCLCPP_ERROR(node->get_logger(), "Goal was canceled");
return 1;
default:
RCLCPP_ERROR(node->get_logger(), "Unknown result code");
return 1;
}
RCLCPP_INFO(node->get_logger(), "result received");
for (auto number : wrapped_result.result->sequence) {
RCLCPP_INFO(node->get_logger(), "%" PRId64, number);
}
- 推荐：ros2风格
#include <inttypes.h>
#include <memory>
#include <string>
#include <iostream>
#include "example_interfaces/action/fibonacci.hpp"
#include "rclcpp/rclcpp.hpp"
// TODO(jacobperron): Remove this once it is included as part of 'rclcpp.hpp'
#include "rclcpp_action/rclcpp_action.hpp"
class MinimalActionClient : public rclcpp::Node
{
public:
using Fibonacci = example_interfaces::action::Fibonacci;
using GoalHandleFibonacci = rclcpp_action::ClientGoalHandle<Fibonacci>;
explicit MinimalActionClient(const rclcpp::NodeOptions & node_options = rclcpp::NodeOptions())
: Node("minimal_action_client", node_options), goal_done_(false)
{
this->client_ptr_ = rclcpp_action::create_client<Fibonacci>(
this->get_node_base_interface(),
this->get_node_graph_interface(),
this->get_node_logging_interface(),
this->get_node_waitables_interface(),
"fibonacci");
this->timer_ = this->create_wall_timer(
std::chrono::milliseconds(500),
std::bind(&MinimalActionClient::send_goal, this));
}
bool is_goal_done() const
{
return this->goal_done_;
}
void send_goal()
{
using namespace std::placeholders;
this->timer_->cancel();
this->goal_done_ = false;
if (!this->client_ptr_) {
RCLCPP_ERROR(this->get_logger(), "Action client not initialized");
}
if (!this->client_ptr_->wait_for_action_server(std::chrono::seconds(10))) {
RCLCPP_ERROR(this->get_logger(), "Action server not available after waiting");
this->goal_done_ = true;
return;
}
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(&MinimalActionClient::goal_response_callback, this, _1);
send_goal_options.feedback_callback =
std::bind(&MinimalActionClient::feedback_callback, this, _1, _2);
send_goal_options.result_callback =
std::bind(&MinimalActionClient::result_callback, this, _1);
auto goal_handle_future = this->client_ptr_->async_send_goal(goal_msg, send_goal_options);
}
private:
rclcpp_action::Client<Fibonacci>::SharedPtr client_ptr_;
rclcpp::TimerBase::SharedPtr timer_;
bool goal_done_;
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)
{
RCLCPP_INFO(
this->get_logger(),
"Next number in sequence received: %" PRId64,
feedback->sequence.back());
}
void result_callback(const GoalHandleFibonacci::WrappedResult & result)
{
this->goal_done_ = true;
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;
}
RCLCPP_INFO(this->get_logger(), "Result received");
for (auto number : result.result->sequence) {
RCLCPP_INFO(this->get_logger(), "%" PRId64, number);
}
}
}; // class MinimalActionClient
int main(int argc, char ** argv)
{
rclcpp::init(argc, argv);
auto action_client = std::make_shared<MinimalActionClient>();
while (!action_client->is_goal_done()) {
rclcpp::spin_some(action_client);
}
rclcpp::shutdown();
return 0;
}
开心洋葱 , 版权所有丨如未注明 , 均为原创丨未经授权请勿修改 , 转载请注明使用机器人操作系统ROS 2和仿真软件Gazebo 9行动进阶实战（九）- mobot区域巡逻！
