participant_->create_topic()中的参数
时间: 2023-06-17 22:05:04 浏览: 48
在participant_->create_topic()中,有以下参数:
1. topic_name: 主题名称,是一个字符串类型的参数,用于标识主题。
2. type_name: 数据类型名称,是一个字符串类型的参数,用于标识主题消息的数据类型。
3. qos_profile: QoS(Quality of Service)配置,是一个QoSProfile类型的参数,用于指定主题的消息传输质量。
4. topic_options: 主题选项,是一个TopicOptions类型的参数,用于设置主题的一些特殊选项,比如是否启用历史消息存储。
其中,topic_name和type_name是必需的参数,qos_profile和topic_options是可选的参数。
相关问题
在fast dds中写个传值调用函数的程序
在Fast DDS中,你可以通过创建一个Publisher和Subscriber来实现传值调用功能。以下是一个简单的示例程序:
```cpp
#include <fastdds/dds/domain/DomainParticipantFactory.hpp>
#include <fastdds/dds/subscriber/Subscriber.hpp>
#include <fastdds/dds/subscriber/SampleInfo.hpp>
#include <fastdds/dds/publisher/Publisher.hpp>
#include <fastdds/dds/topic/Topic.hpp>
#include <fastdds/dds/topic/TypeSupport.hpp>
#include "your_data_type.h" // 你定义的数据类型头文件
using namespace eprosima::fastdds::dds;
class YourDataTypeSubscriber
{
public:
YourDataTypeSubscriber()
{
// 创建DomainParticipant
DomainParticipantQos qos;
participant_ = DomainParticipantFactory::get_instance()->create_participant(0, qos);
// 注册数据类型
YourDataTypeTypeSupport::register_type(participant_);
// 创建Subscriber
subscriber_ = participant_->create_subscriber(SUBSCRIBER_QOS_DEFAULT, nullptr);
// 创建Topic
topic_ = participant_->create_topic("YourDataTypeTopic", "YourDataType", TOPIC_QOS_DEFAULT);
// 创建DataReader和监听器
reader_ = subscriber_->create_datareader(topic_, DATAREADER_QOS_DEFAULT, &listener_);
}
~YourDataTypeSubscriber()
{
// 删除资源
participant_->delete_subscriber(subscriber_);
DomainParticipantFactory::get_instance()->delete_participant(participant_);
}
class YourDataTypeListener : public ReaderListener
{
public:
YourDataTypeListener() = default;
void on_data_available(DataReader* reader) override
{
YourDataType data;
SampleInfo info;
while (reader->take_next_sample(&data, &info) == ReturnCode_t::RETCODE_OK)
{
if (info.valid_data)
{
// 处理收到的数据
// ...
}
}
}
};
private:
DomainParticipant* participant_;
Subscriber* subscriber_;
Topic* topic_;
YourDataTypeListener listener_;
DataReader* reader_;
};
class YourDataTypePublisher
{
public:
YourDataTypePublisher()
{
// 创建DomainParticipant
DomainParticipantQos qos;
participant_ = DomainParticipantFactory::get_instance()->create_participant(0, qos);
// 注册数据类型
YourDataTypeTypeSupport::register_type(participant_);
// 创建Publisher
publisher_ = participant_->create_publisher(PUBLISHER_QOS_DEFAULT, nullptr);
// 创建Topic
topic_ = participant_->create_topic("YourDataTypeTopic", "YourDataType", TOPIC_QOS_DEFAULT);
// 创建DataWriter
writer_ = publisher_->create_datawriter(topic_, DATAWRITER_QOS_DEFAULT);
}
~YourDataTypePublisher()
{
// 删除资源
publisher_->delete_datawriter(writer_);
DomainParticipantFactory::get_instance()->delete_participant(participant_);
}
void publish(const YourDataType& data)
{
// 发布数据
writer_->write(&data);
}
private:
DomainParticipant* participant_;
Publisher* publisher_;
Topic* topic_;
DataWriter* writer_;
};
```
在上面的示例程序中,我们创建了一个`YourDataTypeSubscriber`类和一个`YourDataTypePublisher`类,分别用于接收和发送`YourDataType`类型的数据。我们在`main`函数中使用这两个类来传递数据。
```cpp
int main()
{
YourDataTypePublisher publisher;
YourDataTypeSubscriber subscriber;
while (true)
{
YourDataType data;
// 填充数据
// ...
publisher.publish(data);
// 等待接收数据
// ...
}
return 0;
}
```
在`main`函数中,我们创建了一个`YourDataTypePublisher`对象和一个`YourDataTypeSubscriber`对象,并在一个无限循环中使用`publisher`对象发布数据,然后使用`subscriber`对象接收数据。你可以在`YourDataTypeSubscriber::YourDataTypeListener::on_data_available`方法中处理接收到的数据。
write a C++ example shows how to do force or torque control in offboard mode from a ROS 2 node with XRCE-DDS
Here's an example of how to do force control in offboard mode using C++ and XRCE-DDS:
```cpp
#include <iostream>
#include <chrono>
#include <thread>
#include "rclcpp/rclcpp.hpp"
#include "geometry_msgs/msg/wrench_stamped.hpp"
#include "std_msgs/msg/float64_multi_array.hpp"
#include "rosidl_runtime_cpp/message_type_support_decl.hpp"
#include "rosidl_typesupport_cpp/message_type_support.hpp"
#include "rmw_fastrtps_cpp/get_participant.hpp"
#include "rmw_fastrtps_cpp/get_publisher.hpp"
#include "rmw_fastrtps_cpp/get_subscriber.hpp"
#include "rmw_uros/options.h"
#include "uxr/client/client.h"
#include "sensor_msgs/msg/joint_state.hpp"
using namespace std::chrono_literals;
#define DEFAULT_TIMEOUT 1000
void set_wrench(float fx, float fy, float fz, float tx, float ty, float tz, geometry_msgs::msg::WrenchStamped& wrench)
{
wrench.wrench.force.x = fx;
wrench.wrench.force.y = fy;
wrench.wrench.force.z = fz;
wrench.wrench.torque.x = tx;
wrench.wrench.torque.y = ty;
wrench.wrench.torque.z = tz;
}
class ForceControlNode : public rclcpp::Node
{
public:
ForceControlNode() : Node("force_control_node")
{
joint_state_sub_ = this->create_subscription<sensor_msgs::msg::JointState>("joint_states", 10,
std::bind(&ForceControlNode::joint_state_callback, this, std::placeholders::_1));
wrench_pub_ = this->create_publisher<geometry_msgs::msg::WrenchStamped>("wrench", 10);
setup_dds();
}
private:
void setup_dds()
{
auto domain_id = 0;
uxr_set_custom_transport(uxr::Transport::CUSTOM);
rmw_uros_options_t custom_transport_options = rmw_get_zero_initialized_uros_options();
uxr_init_custom_transport(&custom_transport_options, uxr_common_tcp_platform);
const char* participant_name = "force_control_participant";
const char* topic_name = "force_control_topic";
// Create participant
uxr_init_options_t init_options = uxr_init_options_create();
uxr_set_custom_transport_callbacks(
&init_options,
uxr_common_tcp_platform,
custom_transport_open_cb,
custom_transport_close_cb,
custom_transport_write_cb,
custom_transport_read_cb,
reinterpret_cast<void*>(this));
participant_ = rmw_fastrtps_cpp::get_participant(
this->get_node_base_interface(),
this->get_node_topics_interface(),
domain_id,
participant_name,
"", // empty node namespace
std::vector<std::string>());
// Register ROS message type with XRCE-DDS
const rosidl_message_type_support_t* type_support =
rosidl_typesupport_cpp::get_message_type_support_handle<geometry_msgs::msg::WrenchStamped>();
uxr_register_topic_xml(
&session_,
participant_->impl_->participant,
topic_name,
type_support->typesupport_identifier,
"<dds>"
"<topic>"
"<name>force_control_topic</name>"
"<dataType>geometry_msgs::msg::WrenchStamped_</dataType>"
"</topic>"
"</dds>");
// Create publisher
publisher_ = rmw_fastrtps_cpp::get_publisher(
this->get_node_base_interface(),
this->get_node_topics_interface(),
participant_,
type_support,
topic_name,
"",
&rmw_qos_profile_default);
// Create subscriber
subscriber_ = rmw_fastrtps_cpp::get_subscriber(
this->get_node_base_interface(),
this->get_node_topics_interface(),
participant_,
type_support,
topic_name,
"",
&rmw_qos_profile_default,
false);
// Create session
uxr_init_session_xml(&init_options, &session_, participant_->impl_->participant, domain_id);
UXR_AGENT_LOG_INFO(
&session_.info,
UXR_CREATE_ENTITIES_FROM_REF_RESOURCE,
reinterpret_cast<uint64_t>(participant_->impl_->participant),
session_.last_requested_resource);
// Get publisher and subscriber handles
publisher_handle_ = static_cast<uxrObjectId>(publisher_->publisher_->id_);
subscriber_handle_ = static_cast<uxrObjectId>(subscriber_->subscriber_->id_);
}
void joint_state_callback(const sensor_msgs::msg::JointState::SharedPtr msg)
{
// Compute force and torque based on joint positions and publish to topic
float fx = 0.0;
float fy = 0.0;
float fz = 0.0;
float tx = 0.0;
float ty = 0.0;
float tz = 0.0;
// Compute desired force and torque values here, based on joint positions and other sensor data
geometry_msgs::msg::WrenchStamped wrench;
set_wrench(fx, fy, fz, tx, ty, tz, wrench);
wrench_pub_->publish(wrench);
// Send desired force and torque values to robot using XRCE-DDS
uint8_t buffer[1024];
uint32_t length = 0;
const uint16_t writer_id = 0x01;
const uint16_t reader_id = 0x02;
// Serialize message
ucdrBuffer ub;
ucdr_init_buffer(&ub, buffer, sizeof(buffer));
length = serialize_wrench(msg, &ub);
// Write message to DDS network
uxrStreamId output_stream = uxr_create_output_stream(&session_, UXR_RELIABLE_STREAM);
uxr_prepare_output_stream(&session_, output_stream, publisher_handle_, writer_id, buffer, length);
uxr_run_session_until_timeout(&session_, DEFAULT_TIMEOUT);
uxr_delete_output_stream(&session_, output_stream);
}
uint32_t serialize_wrench(const geometry_msgs::msg::WrenchStamped::SharedPtr msg, ucdrBuffer* ub)
{
uint32_t length = 0;
length += ucdr_serialize_uint32_t(ub, msg->header.stamp.sec);
length += ucdr_serialize_uint32_t(ub, msg->header.stamp.nanosec);
length += ucdr_serialize_float(ub, msg->wrench.force.x);
length += ucdr_serialize_float(ub, msg->wrench.force.y);
length += ucdr_serialize_float(ub, msg->wrench.force.z);
length += ucdr_serialize_float(ub, msg->wrench.torque.x);
length += ucdr_serialize_float(ub, msg->wrench.torque.y);
length += ucdr_serialize_float(ub, msg->wrench.torque.z);
return length;
}
static bool custom_transport_open_cb(void* args, const char* ip, uint16_t port)
{
return true;
}
static bool custom_transport_close_cb(void* args)
{
return true;
}
static size_t custom_transport_write_cb(
void* args,
const uint8_t* buf,
size_t len,
uint8_t* errcode)
{
auto* node = reinterpret_cast<ForceControlNode*>(args);
return node->write_cb(buf, len, errcode);
}
static size_t custom_transport_read_cb(void* args, uint8_t* buf, size_t len, int timeout, uint8_t* errcode)
{
auto* node = reinterpret_cast<ForceControlNode*>(args);
return node->read_cb(buf, len, timeout, errcode);
}
size_t write_cb(const uint8_t* buf, size_t len, uint8_t* errcode)
{
// Write data to ROS topic
geometry_msgs::msg::WrenchStamped wrench;
ucdrBuffer ub;
ucdr_init_buffer(&ub, const_cast<uint8_t*>(buf), len);
deserialize_wrench(&ub, wrench);
wrench_pub_->publish(wrench);
return len;
}
size_t read_cb(uint8_t* buf, size_t len, int timeout, uint8_t* errcode)
{
// Read data from ROS topic
geometry_msgs::msg::WrenchStamped wrench;
if (subscriber_->take(&wrench, nullptr, nullptr) == RMW_RET_OK) {
ucdrBuffer ub;
ucdr_init_buffer(&ub, buf, len);
serialize_wrench(wrench, &ub);
return ub.iterator - ub.init;
}
return 0;
}
void deserialize_wrench(ucdrBuffer* ub, geometry_msgs::msg::WrenchStamped& wrench)
{
wrench.header.stamp.sec = ucdr_deserialize_uint32_t(ub);
wrench.header.stamp.nanosec = ucdr_deserialize_uint32_t(ub);
wrench.wrench.force.x = ucdr_deserialize_float(ub);
wrench.wrench.force.y = ucdr_deserialize_float(ub);
wrench.wrench.force.z = ucdr_deserialize_float(ub);
wrench.wrench.torque.x = ucdr_deserialize_float(ub);
wrench.wrench.torque.y = ucdr_deserialize_float(ub);
wrench.wrench.torque.z = ucdr_deserialize_float(ub);
}
rclcpp::Subscription<sensor_msgs::msg::JointState>::SharedPtr joint_state_sub_;
rclcpp::Publisher<geometry_msgs::msg::WrenchStamped>::SharedPtr wrench_pub_;
rmw_fastrtps_cpp::Participant* participant_;
rmw_fastrtps_cpp::Publisher* publisher_;
rmw_fastrtps_cpp::Subscriber* subscriber_;
uxrSession session_;
uxrObjectId publisher_handle_;
uxrObjectId subscriber_handle_;
};
int main(int argc, char** argv)
{
rclcpp::init(argc, argv);
rclcpp::spin(std::make_shared<ForceControlNode>());
rclcpp::shutdown();
return 0;
}
```
This example subscribes to joint state data and computes the desired force and torque values based on the current joint positions. It then publishes these values to a ROS topic and sends them to the robot using XRCE-DDS. The robot can then use these values to apply the desired force and torque using a force/torque controller.
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