nano学习记录

连接WiFi

nano修改分辨率

查阅了很多博客，其实可能问题会有相似的，但产生的原因可能各不相同，我的环境是win7+Ubuntu16.04的双系统，装好系统后各项功能是完好的，但是第二天开机的时候就出现了连不上网的问题，尝试了很多方法，开始以为是无线驱动的问题，但又查了一些人的博客通过rfkill list命令查看驱动发现网卡是在的，只不过我发现了问题就是我的一个驱动的hard blocked是yes

根据一片博客中写的我将/etc/Network/里的NetworkManage.conf文件中的“manage=false”改成了“manage=true”

然后重启就好了。

报错信息修改

• CMake Error at /opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake:113 (message):
  Project ‘cv_bridge’ specifies ‘/usr/include/opencv’ as an include dir,
  which is not found. It does neither exist as an absolute directory nor in
  ‘${{prefix}}//usr/include/opencv’. Check the issue tracker
  ‘https://github.com/ros-perception/vision_opencv/issues’ and consider
  creating a ticket if the problem has not been reported yet.
  Call Stack (most recent call first):
  /opt/ros/melodic/share/catkin/cmake/catkinConfig.cmake:76 (find_package)
  rikirobot_project/riki_line_follower/CMakeLists.txt:7 (find_package)
  
  解决：安装的是opencv4,位置命名成了/usr/include/opencv4
  sudo vim /opt/ros/melodic/share/cv_bridge/cmake/cv_bridgeConfig.cmake
  改掉第96行
  或者：：：：：：：
  产生这个的原因是：在tx2中我把原来opencv4.1.1版本卸载了，重新安装了opencv3.2

重新安装了cv_bridge，在cv_bridge中找opencv的默认路径不一样，所以要修改。在哪里修改呢？

这里：/opt/ros/melodic/share/cv_bridge/cv_bridgeConfig.cmake

修改哪里呢？

96行

原来是这样子：

PS：原因是：使用sudo apt install ros-melodic-desktop-full安装的ros，那么会默认安装opencv版本到/usr/include,/usr/lib,/usr/share三个目录。但是如果我们从opencv官网源码编译安装的（以最常用的opencv3.2为例）opencv会默认安装到usr/local下对应的三个子目录。
错误qt

qmake: could not exec '/usr/lib/aarch64-linux-gnu/qt4/bin/qmake': No such file or directory
CMake Error at /usr/share/cmake-3.10/Modules/FindQt4.cmake:1320 (message):
  Found unsuitable Qt version "" from NOTFOUND, this code requires Qt 4.x
Call Stack (most recent call first):
  slam_p/hector_slam/hector_geotiff/CMakeLists.txt:12 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/star/starrobot_ws/build/CMakeFiles/CMakeOutput.log".
See also "/home/star/starrobot_ws/build/CMakeFiles/CMakeError.log".
Makefile:6324: recipe for target 'cmake_check_build_system' failed
make: *** [cmake_check_build_system] Error 1
Invoking "make cmake_check_build_system" failed

解决：

sudo apt-get install qt4-default 

重新编译，即可成功``。
或者：
用QT5编译
```py
catkin_make -DUseQt5=ON -j2

解决PLUGINLIB_DECLARE_CLASS 错误

一、问题描述
在catkin_make时候报错：

二、解决办法：
在uvc_camera的源码中/uvc_camera/src/nodelets.cpp 中找到

PLUGINLIB_DECLARE_CLASS(uvc_camera, CameraNodelet, uvc_camera::CameraNodelet, nodelet::Nodelet);
PLUGINLIB_DECLARE_CLASS(uvc_camera, StereoNodelet, uvc_camera::StereoNodelet, nodelet::Nodelet)

把这两行改成：

PLUGINLIB_EXPORT_CLASS(uvc_camera::CameraNodelet , nodelet::Nodelet);
PLUGINLIB_EXPORT_CLASS(uvc_camera::StereoNodelet , nodelet::Nodelet);

参考：
https://blog.youkuaiyun.com/lowbob/article/details/108909168

解决PLUGINLIB_DECLARE_CLASS(turtlebot_follower, TurtlebotFollower, turtlebot_follower::TurtlebotFoll错误

硬件：jetson nano ，TI_mmwave IWR1443
进行Autonomous Robotics with ROS for mmWave时错误记录1。

问题描述：在ros工作区catkin_make,出现错误：

/home/jetbot/TI_ws/src/turtlebot/turtlebot_apps/turtlebot_follower/src/follower.cpp:317:24: error: expected constructor, destructor, or type conversion before ‘(’ token
PLUGINLIB_DECLARE_CLASS(turtlebot_follower, TurtlebotFollower, turtlebot_follower::TurtlebotFollower, nodelet::Nodelet);

解决方案：定位到上述文件位置，打开follower.cpp,将
PLUGINLIB_DECLARE_CLASS(turtlebot_follower, TurtlebotFollower, turtlebot_follower::TurtlebotFollower, nodelet::Nodelet);
更改为：

PLUGINLIB_EXPORT_CLASS(TurtlebotFollower , nodelet::Nodelet);

建议不要用：PLUGINLIB_DECLARE_CLASS，以PLUGINLIB_EXPORT_CLASS替换。其中PLUGINLIB_DECLARE_CLASS的参数为4个，而PLUGINLIB_EXPORT_CLASS的参数为两个。

error: expected constructor, destructor, or type conversion before ‘(’ token PLUGINLIB_DECLARE_CLAS

编译错误：

/home/lly/rikirobot/catkin_ws/src/depth_camera/depthimage_to_laserscan/src/DepthImageToLaserScanNodelet.cpp:60:24: error: expected constructor, destructor, or type conversion before ‘(’ token
PLUGINLIB_DECLARE_CLASS(depthimage_to_laserscan, DepthImageToLaserScanNodelet, depthimage_to_laserscan::DepthImageToLaserScanNodelet, nodelet::Nodelet);
^
depth_camera/depthimage_to_laserscan/CMakeFiles/DepthImageToLaserScanNodelet.dir/build.make:62: recipe for target ‘depth_camera/depthimage_to_laserscan/CMakeFiles/DepthImageToLaserScanNodelet.dir/src/DepthImageToLaserScanNodelet.cpp.o’ failed
make[2]: *** [depth_camera/depthimage_to_laserscan/CMakeFiles/DepthImageToLaserScanNodelet.dir/src/DepthImageToLaserScanNodelet.cpp.o] Error 1
CMakeFiles/Makefile2:6307: recipe for target ‘depth_camera/depthimage_to_laserscan/CMakeFiles/DepthImageToLaserScanNodelet.dir/all’ failed
make[1]: *** [depth_camera/depthimage_to_laserscan/CMakeFiles/DepthImageToLaserScanNodelet.dir/all] Error 2
Makefile:140: recipe for target ‘all’ failed
make: *** [all] Error 2
Invoking “make -j1” failed

出现错误的原因是ubuntu18.04 ros melodic版本与ubuntu16.04 ros kinetic版本中，pluginlib库函数发生了变化。
解决方法：
未修改前的代码：

修改为：

PLUGINLIB_EXPORT_CLASS(depthimage_to_laserscan::DepthImageToLaserScanNodelet, nodelet::Nodelet)

再次编译，即可成功

/home/nano/catkin_ws/src/rikirobot_project/riki_line_follower/src/linedetect.cpp:101:5: error: ‘CV_FONT_HERSHEY_COMPLEX’ was not declared in this scope CV_FONT_HERSHEY_COMPLEX, 1, CV_RGB(255, 0, 0));

解决方法：

简单的，就是直接包含 opencv2/opencv.hpp，如果麻烦一点，就是只添加这个模块的头文件 opencv2/imgproc.hpp
cvPutText的头文件是 opencv2/imgproc/imgproc_c.h

加上#include <opencv2/opencv.hpp> 和using namespace cv;

opencv4中一般取消了cv前缀；应该用FONT_HERSHEY_COMPLEX_SMALL

ros_astra_camera出现问题

https://github.com/alspitz/ros_astra_camera

出现error: RPC failed; curl 18 transfer closed with outstanding read data remain问题

error: RPC failed; curl 18 transfer closed with outstanding read data remaining
 
fatal: The remote end hung up unexpectedly
 
fatal: early EOF
 
fatal: index-pack failed

究其原因是因为curl的postBuffer的默认值太小，我们需要调整它的大小，在终端重新配置大小

在这里，笔者把postBuffer的值配置成500M，对笔者来说已经够了。可以根据你需要下载的文件大小，将postBuffer值配置成合适的大小。

git config --global http.postBuffer 524288000

这样已经配置好了，如果你不确定，可以根据以下命令查看postBuffer。

git config --list