Traceback (most recent call last): File "/opt/ros/noetic/lib/python3/dist-packages/std_msgs/msg/_String.py", line 54, in serialize length = len(_x) TypeError: object of type 'int' has no len() During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 882, in publish self.impl.publish(data) File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 1066, in publish serialize_message(b, self.seq, message) File "/opt/ros/noetic/lib/python3/dist-packages/rospy/msg.py", line 152, in serialize_message msg.serialize(b) File "/opt/ros/noetic/lib/python3/dist-packages/std_msgs/msg/_String.py", line 60, in serialize except TypeError as te: self._check_types(ValueError("%s: '%s' when writing '%s'" % (type(te), str(te), str(locals().get('_x', self))))) File "/opt/ros/noetic/lib/python3/dist-packages/genpy/message.py", line 393, in _check_types check_type(n, t, getattr(self, n)) File "/opt/ros/noetic/lib/python3/dist-packages/genpy/message.py", line 285, in check_type raise SerializationError('field %s must be of type bytes or an ascii string' % field_name) genpy.message.SerializationError: field data must be of type bytes or an ascii string During handling of the above exception, another exception occurred: Traceback (most recent call last): File "sub.py", line 45, in <module> pub_2.publish(bucket) File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 886, in publish raise ROSSerializationException(str(e)) rospy.exceptions.ROSSerializationException: field data must be of type bytes or an ascii string

这个错误提示是在ROS中发布消息时的序列化错误。它表明消息中的某个字段必须是字节或ASCII字符串类型，但是实际上它是一个整数类型，无法被序列化。

你需要检查发布代码中的消息格式，确保消息中的所有字段都具有正确的数据类型。如果你使用的是自定义消息，请确保消息定义中的所有字段都已正确定义。你还可以使用ROS中的rostopic echo命令来检查消息是否正确发布。

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。

Traceback (most recent call last): File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/__init__.py", line 290, in main write_pid_file(options.pid_fn, options.core, options.port) File "/opt/ros/melodic/lib/python2.7/dist-packages/roslaunch/__init__.py", line 112, in write_pid_file with open(pid_fn, "w") as f: IOError: [Errno 13] Permission denied: '/home/wzx/.ros/roscore-11311.pid'

这个错误是由于权限问题导致的。IOError: [Errno 13] Permission denied 表示你没有权限在该路径下创建文件。解决这个问题的一种方法是使用管理员权限运行你的程序。你可以尝试使用sudo命令，在终端中输入以下命令运行你的程序：

sudo python your_program.py

这样可以使用管理员权限运行你的程序，从而解决权限问题。请注意，在使用sudo命令时要小心，确保你信任该程序，以避免不必要的安全风险。