Reason: the cmakelists.txt file does not specify the DNN module, so the statement
find_package(OpenCV 4 REQUIRED opencv_core opencv_imgproc opencv_highgui opencv_calib3d opencv_videoio opencv_imgcodecs )To be amended as follows:
find_package(OpenCV 4 REQUIRED)It can be compiled.
The reason lies in the CV of ROS_ Bridge only supports python2. If you want to use python3, you need to compile CV by yourself_ Bridge bag. My environment: Ubuntu 18.04 + ROS + Python 3.6 (anaconda3 is installed, but Python 3.6 is used)
refer to the first answer in the link for specific steps (like more answers):
Running catkin on Ubuntu 16.04 gazebo7_ Cmake error
Error details:
CMake Error at /opt/ros/kinetic/share/catkin/cmake/catkinConfig.cmake:83 (find_package):
Could not find a package configuration file provided by "gazebo_plugins"
with any of the following names:
gazebo_pluginsConfig.cmake
gazebo_plugins-config.cmake
terms of settlement:
sudo apt-get install ros-kinetic-gazebo-ros-pkgs ros-kinetic-gazebo-ros-control
Catkin make
Question: as the title, open it plugin.xml It was found to be blank.
Solution: find the GitHub of PR2, download and copy it to/opt/ROS/melody/share/PR2_ moto_ diagnostic_ Tool/or create your own plugin.xml File, which will be installed on GitHub plugin.xml Copy in the code in.
[new problem] prompts that we do not have permission to create a file in this path, so we need to increase the permission to obtain the super user permission: $sudo Chmod 777/opt/ROS/melody/share/PR2_ motor_ diagnostic_ tool/。 Then create a new one plugin.xml File, copy the code in and save it.
Problem Description:
[robot_launch.launch] is neither a launch file in package [kinova_gazebo] nor is [kinova_gazebo] a launch file name
The traceback for the exception was written to the log file
terms of settlement:
The error indicates that the corresponding package is not installed in the ROS system. In this case, go to the top of the project file and use catkin_ The make command compiles the file. If it is executed again at this time, an error will still be reported. Then add another statement:
source devel/setup.bash
Will devel/ setup.bash Add to the system, and then run 
terms of settlement
1. Terminal input sudo apt get clean
2
reference
1. The article also mentioned other solutions
2. ROS installation tutorial
Policy CMP0054 is not set: Only interpret if（） arguments as variables or keywords when unquoted
Refer to prompt cause solution
reference resources
How to use variables and avoid CMP0054 policy violations?CMP0054
Prompt reason
Note: You only get the CMP0054 warning if the context of your variable was actually evaluated again (so it’s a hint your CMake code will not work in those places).
solve
cmake_policy(SET CMP0054 NEW)
report errors:
Unable to open camera calibration file [/home/hri/.ros/camera_ info/head_ camera.yaml ]
reference resources:
https://github.com/ros-drivers/usb_ cam/issues/53
https://answers.ros.org/question/217806/rospack-error-package-image_ view-not-found/
reason:
The main reason is that image is not installed_ View
ahaaha
terms of settlement:
sudo apt-get install ros-indigo-image-view
gedit ~/.bashrc
The last line, comment out the source/opt/ros/kinetic/setup. Bash (adding #)
qt-ros:
/usr/include/boost/type_traits/ has_binary_operation.hp :50: Parse error at “BOOST_JOIN” error
temporary solution:
modify /usr/include/boost/type_traits/detail/ has_binary_operation.hpp file
namespace BOOST_JOIN(BOOST_TT_TRAIT_NAME,_impl) {
..
}
to
#ifndef Q_MOC_RUN
namespace BOOST_JOIN(BOOST_TT_TRAIT_NAME,_impl) {
#endif
…
#ifndef Q_MOC_RUN
}
#endif