Zhenpeng Ge

i agree that deep inheritance hierarchy is hard to understand for beginner.

CC @jwallace42

> If callback groups aren't being respected, how does bypassing the unsubscribe help? Per rclcpp issue thread maybe I don't get your meaning，the problem is caused by `subscribe()`, not related...

the problem is that Obstacle Layer not working (the scan data isn't subscribed by Obstacle Layer), becasue `observation_subscribers_->subsciber()` failed when `ObstacleLayer::activate()` is called. it seems that we can't create subscriber...

@ahcorde , hi, it's a good suggestion, i tried to convert custom plugins to `gz_ros2_control`, you can see more details in this PR https://github.com/gezp/universal_robot_ign/pull/4 , but i failed to create...

is anyone working for this? if not, i would like to continue this work for python implementation.

> but it doesn't look like the rclpy executor API supports callback groups sorry, i didn't notice that rclpy API is some different of rlcpp before. you are right, we...

消息同步不建议直接使用ros的message_filters，使用buffer自行处理会更加灵活。在rmoss设计模式中，ROS2主要作为消息通讯的中间件，topic数据的读取尽可能保持原生形式，并采用自己的算法进行同步等处理，不依赖于ROS。

readme倒是可以支持一下，tutorial website感觉现在没必要现在支持，现在看来这个项目有很多不成熟的地方，后面如果发生更新，多语言维护起来会比较麻烦。

实现步骤： * 使用tf2完成基本的自瞄功能：https://github.com/robomaster-oss/rmoss_contrib/pull/3 * 使用`tf2_ros::MessageFilter`实现消息同步：https://github.com/robomaster-oss/rmoss_contrib/pull/6