四、ROS串口通讯节点
ROS串口通讯节点接收Twist格式的/cmd_vel话题，并将角速度和线速度以串口的形式发送到单片机，从而控制电机运动。
一、安装ROS串口驱动
1、安装cutecom并打开
sudo apt-get install cutecom sudo cutecom
2、下载serial软件包
sudo apt-get install ros-kinetic-serial #ros为Kinect版本
3、进入下载的软件包的位置
roscd serial
若是安装成功会看到：
$:/opt/ros/kinetic/share/serial
二、节点代码如下：
#include "ros/ros.h" #include <geometry_msgs/Twist.h> #include <string> #include <iostream> #include <cstdio> #include <unistd.h> #include <math.h> #include "serial/serial.h" using namespace std; float ratio = 1000.0f;//转速转换比例，执行速度调整比例 float D = 0.32f;//两轮间距，单位是m; float linear_temp = 0, angular_temp = 0;//暂存的线速度和角速度 unsigned char data_terminal0 = 0x0d;//"/r"字符 unsigned char data_terminal1 = 0x0a;//"/n"字符 unsigned char speed_data[10] = {0};//发送给串口的数据 //定义串口 serial::Serial my_serial; //发送给下位机的左右轮速度 union floatData { float d; unsigned char data[4]; }right_speed_data, left_speed_data; void callback(const geometry_msgs::Twist& cmd_input)//订阅 /cmd_vel话题回调函数 { angular_temp = cmd_input.angular.z;//获取/cmd_vel角速度,rad/s linear_temp = cmd_input.linear.x;//获取/cmd_vel线速度，m/s //将角速度和线速度转换成两个车轮的速度 left_speed_data.d = linear_temp - 0.5f*angular_temp*D; right_speed_data.d = linear_temp + 0.5f*angular_temp*D; //存入数据到要发布的左右轮速度消息 left_speed_data.d *= ratio;//放大1000倍，mm/s right_speed_data.d *= ratio;//放大1000倍，mm/s for(int i=0; i<4; i++) { speed_data[i] = right_speed_data.data[i]; speed_data[i+4] = left_speed_data.data[i]; } speed_data[8] = data_terminal0; speed_data[9] = data_terminal1; //写入数据到串口 if(my_serial.isOpen()) { my_serial.write(speed_data, 10); ROS_INFO_STREAM("Serial Port is OK, data is sending......"); } } int main(int argc, char** argv) { my_serial.setPort("/dev/ttyUSB1"); my_serial.setBaudrate(115200); serial::Timeout to = serial::Timeout::simpleTimeout(1000); my_serial.setTimeout(to); try { my_serial.open(); } catch(serial::IOException &e) { ROS_ERROR_STREAM("Unable to open port"); return -1; } if(my_serial.isOpen()) { ROS_INFO_STREAM("Serial Port Initialized"); } else return -1; ros::init(argc, argv, "twist_to_serial"); ros::NodeHandle n; ros::Subscriber sub = n.subscribe("cmd_vel", 20, callback);//订阅 /cmd_vel话题 ros::spin(); return 0; }
三、CMakeLists.txt文件配置
cmake_minimum_required(VERSION 3.0.2) project(twist_to_serial) ## Compile as C++11, supported in ROS Kinetic and newer # add_compile_options(-std=c++11) ## Find catkin macros and libraries ## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz) ## is used, also find other catkin packages find_package(catkin REQUIRED COMPONENTS roscpp rospy std_msgs message_generation serial nav_msgs ) ## System dependencies are found with CMake's conventions # find_package(Boost REQUIRED COMPONENTS system) ## Uncomment this if the package has a setup.py. This macro ensures ## modules and global scripts declared therein get installed ## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html # catkin_python_setup() ################################################ ## Declare ROS messages, services and actions ## ################################################ ## To declare and build messages, services or actions from within this ## package, follow these steps: ## * Let MSG_DEP_SET be the set of packages whose message types you use in ## your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...). ## * In the file package.xml: ## * add a build_depend tag for "message_generation" ## * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET ## * If MSG_DEP_SET isn't empty the following dependency has been pulled in ## but can be declared for certainty nonetheless: ## * add a exec_depend tag for "message_runtime" ## * In this file (CMakeLists.txt): ## * add "message_generation" and every package in MSG_DEP_SET to ## find_package(catkin REQUIRED COMPONENTS ...) ## * add "message_runtime" and every package in MSG_DEP_SET to ## catkin_package(CATKIN_DEPENDS ...) ## * uncomment the add_*_files sections below as needed ## and list every .msg/.srv/.action file to be processed ## * uncomment the generate_messages entry below ## * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...) ## Generate messages in the 'msg' folder # add_message_files( # FILES # Message1.msg # Message2.msg # ) ## Generate services in the 'srv' folder # add_service_files( # FILES # Service1.srv # Service2.srv # ) ## Generate actions in the 'action' folder # add_action_files( # FILES # Action1.action # Action2.action # ) ## Generate added messages and services with any dependencies listed here # generate_messages( # DEPENDENCIES # std_msgs # Or other packages containing msgs # ) ################################################ ## Declare ROS dynamic reconfigure parameters ## ################################################ ## To declare and build dynamic reconfigure parameters within this ## package, follow these steps: ## * In the file package.xml: ## * add a build_depend and a exec_depend tag for "dynamic_reconfigure" ## * In this file (CMakeLists.txt): ## * add "dynamic_reconfigure" to ## find_package(catkin REQUIRED COMPONENTS ...) ## * uncomment the "generate_dynamic_reconfigure_options" section below ## and list every .cfg file to be processed ## Generate dynamic reconfigure parameters in the 'cfg' folder # generate_dynamic_reconfigure_options( # cfg/DynReconf1.cfg # cfg/DynReconf2.cfg # ) ################################### ## catkin specific configuration ## ################################### ## The catkin_package macro generates cmake config files for your package ## Declare things to be passed to dependent projects ## INCLUDE_DIRS: uncomment this if your package contains header files ## LIBRARIES: libraries you create in this project that dependent projects also need ## CATKIN_DEPENDS: catkin_packages dependent projects also need ## DEPENDS: system dependencies of this project that dependent projects also need catkin_package( # INCLUDE_DIRS include # LIBRARIES twist_to_serial CATKIN_DEPENDS roscpp rospy std_msgs serial # DEPENDS system_lib ) ########### ## Build ## ########### ## Specify additional locations of header files ## Your package locations should be listed before other locations include_directories( # include ${catkin_INCLUDE_DIRS} ${serial_INCLUDE_DIRS} ) ## Declare a C++ library # add_library(${PROJECT_NAME} # src/${PROJECT_NAME}/twist_to_serial.cpp # ) ## Add cmake target dependencies of the library ## as an example, code may need to be generated before libraries ## either from message generation or dynamic reconfigure # add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS}) ## Declare a C++ executable ## With catkin_make all packages are built within a single CMake context ## The recommended prefix ensures that target names across packages don't collide add_executable(twist_to_serial src/twist_to_serial.cpp) ## Rename C++ executable without prefix ## The above recommended prefix causes long target names, the following renames the ## target back to the shorter version for ease of user use ## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node" # set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "") ## Add cmake target dependencies of the executable ## same as for the library above # add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS}) ## Specify libraries to link a library or executable target against target_link_libraries(twist_to_serial ${catkin_LIBRARIES} ) ############# ## Install ## ############# # all install targets should use catkin DESTINATION variables # See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html ## Mark executable scripts (Python etc.) for installation ## in contrast to setup.py, you can choose the destination # catkin_install_python(PROGRAMS # scripts/my_python_script # DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} # ) ## Mark executables for installation ## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html # install(TARGETS ${PROJECT_NAME}_node # RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} # ) ## Mark libraries for installation ## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html # install(TARGETS ${PROJECT_NAME} # ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION} # LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION} # RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION} # ) ## Mark cpp header files for installation # install(DIRECTORY include/${PROJECT_NAME}/ # DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION} # FILES_MATCHING PATTERN "*.h" # PATTERN ".svn" EXCLUDE # ) ## Mark other files for installation (e.g. launch and bag files, etc.) # install(FILES # # myfile1 # # myfile2 # DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION} # ) ############# ## Testing ## ############# ## Add gtest based cpp test target and link libraries # catkin_add_gtest(${PROJECT_NAME}-test test/test_twist_to_serial.cpp) # if(TARGET ${PROJECT_NAME}-test) # target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME}) # endif() ## Add folders to be run by python nosetests # catkin_add_nosetests(test)
四、package.xml文件配置
<?xml version="1.0"?> <package format="2"> <name>twist_to_serial</name> <version>0.0.0</version> <description>The twist_to_serial package</description> <!-- One maintainer tag required, multiple allowed, one person per tag --> <!-- Example: --> <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> --> <maintainer email="oay@todo.todo">oay</maintainer> <!-- One license tag required, multiple allowed, one license per tag --> <!-- Commonly used license strings: --> <!-- BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 --> <license>TODO</license> <!-- Url tags are optional, but multiple are allowed, one per tag --> <!-- Optional attribute type can be: website, bugtracker, or repository --> <!-- Example: --> <!-- <url type="website">http://wiki.ros.org/twist_to_serial</url> --> <!-- Author tags are optional, multiple are allowed, one per tag --> <!-- Authors do not have to be maintainers, but could be --> <!-- Example: --> <!-- <author email="jane.doe@example.com">Jane Doe</author> --> <!-- The *depend tags are used to specify dependencies --> <!-- Dependencies can be catkin packages or system dependencies --> <!-- Examples: --> <!-- Use depend as a shortcut for packages that are both build and exec dependencies --> <!-- <depend>roscpp</depend> --> <!-- Note that this is equivalent to the following: --> <!-- <build_depend>roscpp</build_depend> --> <!-- <exec_depend>roscpp</exec_depend> --> <!-- Use build_depend for packages you need at compile time: --> <!-- <build_depend>message_generation</build_depend> --> <!-- Use build_export_depend for packages you need in order to build against this package: --> <!-- <build_export_depend>message_generation</build_export_depend> --> <!-- Use buildtool_depend for build tool packages: --> <!-- <buildtool_depend>catkin</buildtool_depend> --> <!-- Use exec_depend for packages you need at runtime: --> <!-- <exec_depend>message_runtime</exec_depend> --> <!-- Use test_depend for packages you need only for testing: --> <!-- <test_depend>gtest</test_depend> --> <!-- Use doc_depend for packages you need only for building documentation: --> <!-- <doc_depend>doxygen</doc_depend> --> <buildtool_depend>catkin</buildtool_depend> <build_depend>roscpp</build_depend> <build_export_depend>roscpp</build_export_depend> <exec_depend>roscpp</exec_depend> <build_depend>rospy</build_depend> <build_export_depend>rospy</build_export_depend> <exec_depend>rospy</exec_depend> <build_depend>std_msgs</build_depend> <build_export_depend>std_msgs</build_export_depend> <exec_depend>std_msgs</exec_depend> <build_depend>serial</build_depend> <build_export_depend>serial</build_export_depend> <exec_depend>serial</exec_depend> <!-- The export tag contains other, unspecified, tags --> <export> <!-- Other tools can request additional information be placed here --> </export> </package>
