ROS2 std_msgs/Header header
时间: 2024-05-24 21:12:45 浏览: 361
The std_msgs/Header is a message type in ROS2 that contains a header field of type std_msgs/Header. The header field contains the following information:
- sequence number (uint32) - a unique ID for each message sent
- timestamp (time) - the time when the message was sent
- frame_id (string) - the coordinate frame in which the data is defined
The header field is used to provide context to the message data and to ensure that messages are processed in the correct order.
相关问题
Traceback (most recent call last): File "/home/ros/catkin_ctr/src/jiangluo/scripts/eight_zi.py", line 47, in <module> local_pos_pub3.publish(poscom_twist) File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 879, in publish data = args_kwds_to_message(self.data_class, args, kwds) File "/opt/ros/noetic/lib/python3/dist-packages/rospy/msg.py", line 121, in args_kwds_to_message raise TypeError("expected [%s] but got [%s]"%(data_class._slot_types[0], arg._type)) TypeError: expected [std_msgs/Header] but got [geometry_msgs/TwistStamped]
这个错误提示意味着在 `local_pos_pub3.publish(poscom_twist)` 这一行代码中,你正在尝试将一个 `geometry_msgs/TwistStamped` 对象发布到了 `poscom` 这个话题上,但是这两者的消息类型并不匹配。
根据错误提示,`poscom` 这个话题所期望的消息类型是 `std_msgs/Header`,而不是 `geometry_msgs/TwistStamped`。因此,你需要将 `poscom` 话题和 `poscom_twist` 话题分别发布。
修改后的代码应该类似于以下代码:
```
while not rospy.is_shutdown():
poscom.header.stamp = rospy.Time.now()
poscom.header.frame_id = "world"
poscom.pose.position.x = 2.5 * math.sin(math.pi * i / 400)
poscom.pose.position.y = 5 * math.sin(math.pi * i / 800)
poscom.pose.position.z = 2
poscom_twist = TwistStamped()
poscom_twist.header.stamp = rospy.Time.now()
poscom_twist.header.frame_id = "base_link"
poscom_twist.twist.linear.x = 0
poscom_twist.twist.linear.y = 0
poscom_twist.twist.linear.z = 0
poscom_twist.twist.angular.x = 0
poscom_twist.twist.angular.y = 0
poscom_twist.twist.angular.z = 0
local_pos_pub3.publish(poscom)
local_pos_pub4.publish(poscom_twist) # 将 poscom_twist 发布到另一个话题上
```
你需要在你的代码中找到 `local_pos_pub3` 这个发布者,并对其进行修改,使其发布到正确的话题上(也就是 `poscom_twist`)。记得要在你的代码中添加一个新的发布者 `local_pos_pub4`,并将其发布到 `poscom_twist` 这个话题上。
希望这可以帮助你解决问题。
ros2 std_msgs的用法
ROS2 (Robot Operating System version 2) 的 `std_msgs` 包提供了一组基本的消息类型,用于在节点间交换数据。这些消息是跨平台的,并且是所有ROS2系统的核心组件之一。`std_msgs` 消息包括像 `String`, `Int8`, `Float32`, `Bool`, 等基础类型,以及一些更复杂的数据结构如 `Message` 和 `Header`。
以下是使用 `std_msgs` 的常见步骤:
1. **包含头文件**:在需要使用 `std_msgs` 的节点的`.cpp` 或 `.h` 文件中,首先要添加相应的头文件,例如:
```c++
#include <ros2/core/time.hpp>
#include <std_msgs/msg/string.hpp>
```
2. **创建消息实例**:声明并初始化你需要的消息类型,比如发送字符串消息:
```c++
std_msgs::msg::String msg;
msg.data = "Hello ROS2";
```
3. **发布消息**:通过`rclcpp`或者其他ROS2客户端库,你可以创建`Publisher`对象来发布消息:
```c++
auto publisher = node.create_publisher<std_msgs::msg::String>("topic_name", 10); // topic_name是你选择的主题名
publisher->publish(msg);
```
4. **订阅消息**:接收者可以创建一个`Subscriber`来订阅主题并处理接收到的消息:
```c++
auto subscription = node.create_subscription<std_msgs::msg::String>(
"topic_name", 10,
[this](const std_msgs::msg::String::SharedPtr msg) { handle_message(*msg); },
rclcpp::QoS(1));
```
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