ros2 py文件间函数调用

写在前面的话

在 ros2 新建依赖 python 的工程包（package）的命令如下，生成的文件结构如下图。在 setup.py 文件里面已经默认指定了运行的函数是 keyboard_control.py 的 main 函数，这篇文章解决的是需要调用另一个python文件的函数，遇到的报错问题限于我个人，可以参考…

生成python工程包命令

ros2 pkg create keyboard_control --build-type ament_python --dependencies rclpy --node-name keyboard_control

运行python函数命令

ros2 run keyboard_control keyboard_control

python工程包的目录结构

目录结构（细节）

终端打印目录结构需要用到 tree ，安装即可sudo apt install tree

xucg@xucg-vm17:~/xu_nav_ws/src/keyboard_control$ tree
.
├── keyboard_control
│   ├── can_control.py
│   ├── __init__.py
│   └── keyboard_control.py
├── package.xml
├── resource
│   └── keyboard_control
├── setup.cfg
├── setup.py
└── test
    ├── test_copyright.py
    ├── test_flake8.py
    └── test_pep257.py

3 directories, 10 files

报错 1（ no module name ‘***’）

错误示意 截图

终端输出

xucg@xucg-vm17:~/xu_nav_ws$ colcon build
Starting >>> keyboard_control
Finished <<< keyboard_control [3.91s]          

Summary: 1 package finished [4.59s]
xucg@xucg-vm17:~/xu_nav_ws$ ros2 run keyboard_control keyboard_control 
Traceback (most recent call last):
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/keyboard_control/keyboard_control", line 33, in <module>
    sys.exit(load_entry_point('keyboard-control==0.0.0', 'console_scripts', 'keyboard_control')())
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/keyboard_control/keyboard_control", line 25, in importlib_load_entry_point
    return next(matches).load()
  File "/usr/lib/python3.10/importlib/metadata/__init__.py", line 171, in load
    module = import_module(match.group('module'))
  File "/usr/lib/python3.10/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1050, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1027, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1006, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 688, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 883, in exec_module
  File "<frozen importlib._bootstrap>", line 241, in _call_with_frames_removed
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/python3.10/site-packages/keyboard_control/keyboard_control.py", line 20, in <module>
    from can_control import can_controller
ModuleNotFoundError: No module named 'can_control'
[ros2run]: Process exited with failure 1

解决方法

需要指定到 python 文件的上级目录
from can_control import can_controller >> from keyboard_control.can_control import can_controller

报错 2（ AttributeError: ‘***’ object has no attribute ‘_default_callback_group’）

终端输出

xucg@xucg-vm17:~/xu_nav_ws$ colcon build
Starting >>> keyboard_control
Finished <<< keyboard_control [3.88s]          

Summary: 1 package finished [4.57s]
xucg@xucg-vm17:~/xu_nav_ws$ ros2 run keyboard_control keyboard_control 
Traceback (most recent call last):
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/keyboard_control/keyboard_control", line 33, in <module>
    sys.exit(load_entry_point('keyboard-control==0.0.0', 'console_scripts', 'keyboard_control')())
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/python3.10/site-packages/keyboard_control/keyboard_control.py", line 145, in main
    car_controller = can_controller()
  File "/home/xucg/xu_nav_ws/install/keyboard_control/lib/python3.10/site-packages/keyboard_control/can_control.py", line 221, in __init__
    self.sub_vel = self.create_subscription(Twist,'/keyboard_vel_msg', self.vel_callback, 1)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/node.py", line 1347, in create_subscription
    callback_group = callback_group or self.default_callback_group
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/node.py", line 304, in default_callback_group
    return self._default_callback_group
AttributeError: 'can_controller' object has no attribute '_default_callback_group'. Did you mean: 'default_callback_group'?
[ros2run]: Process exited with failure 1

错误示意 截图

解决方法

在调用的函数 __init__(self):下面一行加上super().__init__('函数类名称')即可

成功运行

xucg@xucg-vm17:~/xu_nav_ws$ colcon build
Starting >>> keyboard_control
Finished <<< keyboard_control [4.25s]          

Summary: 1 package finished [4.99s]
xucg@xucg-vm17:~/xu_nav_ws$ ros2 run keyboard_control keyboard_control 
[17664, 5, 191, 35387, 15, 15, [b'\x03', b'\x1c', b'\x7f', b'\x15', b'\x04', b'\x00', b'\x01', b'\x00', b'\x11', b'\x13', b'\x1a', b'\x00', b'\x12', b'\x0f', b'\x17', b'\x16', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00', b'\x00']]

        Reading from the keyboard  and Publishing to Twist!
        ---------------------------
        注意：r是停止，角速度不能设置太大会导致转弯不稳车身摆动,

        Moving around:
        q   w   e 
        a   s   d  
        z       c

        anything else : stop
        ,/. : increase/decrease max speed by 10%
        v/b : increase/decrease only linear speed by 10%
        n/m : increase/decrease only angular speed by 10%


        CTRL-C to quit
        
currently: 	speed(0.0) 	turn(0.0)

运行示意 截图