《ROS精品入门》学习笔记五：ROS仿真

一.学习内容
本节课主要讲了一下内容：
1.ROS中的仿真工具stage的使用
2.ROS中Rviz的使用
二.学习讲义



三.学习笔记
1. 这一章相当于介绍了两个工具stage和rviz，比较好理解。如下图，stage仿真时stageros节点订阅了一些topic也发布了一些topic，我们通过自己写一些节点与其进行通信即可。比如，我们可以使用gmapping通过/base_scan的数据来建图，示例中也是通过这种方式（节点mystage）实现了碰到障碍物停止。

2. 教程中还演示了turtlebot在stage中的仿真，看了眼节点图，好复杂。。。倒是可以平常没事看看理解理解。话说提到仿真别人都会说gazebo很少提及stage，可能是功能比较简陋吧。

3.关于Rviz，作为一个显示工具，其核心功能就在于可以可视化各种各样的messages，这一点PPT的P8、9页有详细介绍。
四.相关源码
package目录树：

my_stage--include--src   --my_stage.cpp--CMakeLists.txt--package.xml

源码：
my_stage.cpp:

#include<ros/ros.h>#include<sensor_msgs/LaserScan.h>#include<geometry_msgs/Twist.h>class Stopper{public:    const static double FORWARD_SPEED_MPS=0.1;  //运动速度    const static double MIN_SCAN_ANGLE_RAD=-30.0/180*M_PI; //最小角度    const static double MAX_SCAN_ANGLE_RAD=30.0/180*M_PI;  //最大角度    const static float MIN_PROXIMITY_RANGE_M=0.5;  //期望的最近距离    Stopper();  //构造函数    void startMoving();private:    ros::NodeHandle node;     //私有成员    ros::Publisher commandPub;    ros::Subscriber laserSub;    bool keepMoving;       //指示器    void moveForward();    void scanCallback(const sensor_msgs::LaserScan::ConstPtr& scan);  //回调函数};//构造函数Stopper::Stopper() {    keepMoving=true;    commandPub=node.advertise<geometry_msgs::Twist>("cmd_vel", 10);    laserSub=node.subscribe("base_scan", 1, &Stopper::scanCallback, this);}//发布向前移动消息void Stopper::moveForward(){    geometry_msgs::Twist msg;    msg.linear.x=FORWARD_SPEED_MPS;    commandPub.publish(msg);}//回调函数，若最近距离小于指定值，更改keepMoving标志为Falsevoid Stopper::scanCallback(const sensor_msgs::LaserScan::ConstPtr &scan) {    int minIndex=ceil(MIN_SCAN_ANGLE_RAD-scan->angle_min)/scan->angle_increment;    int maxIndex=floor(MAX_SCAN_ANGLE_RAD-scan->angle_min)/scan->angle_increment;    float closestRange=scan->ranges[minIndex];    for(int currIndex=minIndex+1; currIndex<=maxIndex; currIndex++) {        if(scan->ranges[currIndex] < closestRange) {            closestRange=scan->ranges[currIndex];        }    }    ROS_INFO_STREAM("Closest_range: " << closestRange);    if(closestRange<MIN_PROXIMITY_RANGE_M){        ROS_INFO("Stop!");        keepMoving=false;    }}//开始移动，一直循环发送moveForward()直到keepMoving标志变为Falsevoid Stopper::startMoving(){    ros::Rate rate(10);    ROS_INFO("start moving");    while(ros::ok()&&keepMoving){        moveForward();        ros::spinOnce();        rate.sleep();    }}int main(int argc, char** argv){    ros::init(argc, argv, "mystage");    Stopper stopper;    stopper.startMoving();    return 0;}

CMakeLists.txt:

cmake_minimum_required(VERSION 2.8.3)project(my_stage)## Find catkin macros and libraries## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)## is used, also find other catkin packagesfind_package(catkin REQUIRED COMPONENTS  roscpp  std_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 run_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 run_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# )################################################## 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 run_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 you 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 needcatkin_package(#  INCLUDE_DIRS include#  LIBRARIES my_stage#  CATKIN_DEPENDS roscpp std_msgs#  DEPENDS system_lib)############# Build ############### Specify additional locations of header files## Your package locations should be listed before other locations# include_directories(include)include_directories(  ${catkin_INCLUDE_DIRS})## Declare a C++ library# add_library(my_stage#   src/${PROJECT_NAME}/my_stage.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(my_stage ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})## Declare a C++ executable add_executable(my_stage src/my_stage.cpp)## Add cmake target dependencies of the executable## same as for the library above# add_dependencies(my_stage_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})## Specify libraries to link a library or executable target against target_link_libraries(my_stage   ${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# install(PROGRAMS#   scripts/my_python_script#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}# )## Mark executables and/or libraries for installation# install(TARGETS my_stage my_stage_node#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}# )## Mark cpp header files for installation# install(DIRECTORY include/${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_my_stage.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)

package.xml:

<?xml version="1.0"?><package>  <name>my_stage</name>  <version>0.0.0</version>  <description>The my_stage package</description>  <!-- One maintainer tag required, multiple allowed, one person per tag -->   <!-- Example:  -->  <!-- <maintainer email="[e-mail]">Jane Doe</maintainer> -->  <maintainer email="[e-mail]">aicrobo</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 mutiple are allowed, one per tag -->  <!-- Optional attribute type can be: website, bugtracker, or repository -->  <!-- Example: -->  <!-- <url type="website">http://wiki.ros.org/my_stage</url> -->  <!-- Author tags are optional, mutiple are allowed, one per tag -->  <!-- Authors do not have to be maintianers, but could be -->  <!-- Example: -->  <!-- <author email="[e-mail]">Jane Doe</author> -->  <!-- The *_depend tags are used to specify dependencies -->  <!-- Dependencies can be catkin packages or system dependencies -->  <!-- Examples: -->  <!-- Use build_depend for packages you need at compile time: -->  <!--   <build_depend>message_generation</build_depend> -->  <!-- Use buildtool_depend for build tool packages: -->  <!--   <buildtool_depend>catkin</buildtool_depend> -->  <!-- Use run_depend for packages you need at runtime: -->  <!--   <run_depend>message_runtime</run_depend> -->  <!-- Use test_depend for packages you need only for testing: -->  <!--   <test_depend>gtest</test_depend> -->  <buildtool_depend>catkin</buildtool_depend>  <build_depend>roscpp</build_depend>  <build_depend>std_msgs</build_depend>  <run_depend>roscpp</run_depend>  <run_depend>std_msgs</run_depend>  <!-- The export tag contains other, unspecified, tags -->  <export>    <!-- Other tools can request additional information be placed here -->  </export></package>