1.启动gazebo并加载空地图

roslaunch mbot_gazebo nav_gmapping_view_mbot_gazebolaserandcamera_room.launch

2.命令行发送cmd_vel指令

rostopic list 查看话题类型

rostopic pub -r 10 /cmd_vel 按两下 Tab键，命令即补全

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist "linear:x: 0.0y: 0.0z: 0.0
angular:x: 0.0y: 0.0z: 0.0"

先让机器人转圈,输入这个命令

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist "linear:x: 2.0y: 0.0z: 0.0
angular:x: 0.0y: 0.0z:-0.5"

让机器人直行，输入

rostopic pub -r 10 /cmd_vel geometry_msgs/Twist "linear:x: 2.0y: 0.0z: 0.0
angular:x: 0.0y: 0.0z: 0.0"

4./cmd_vel geometry_msgs/Twist使用示例

新建一个节点不断发送/cmd_vel控制机器人运动的节点

mkdir -p cmdveltest/src
cd cmdveltest/src
catkin_create_pkg cmdveltest geometry_msgs
mkdir src
cd src
touch cmdveltest.cpp
cd cmdveltest/src
catkin_make

在CMakeLists.txt
加入

add_executable(cmdveltest src/cmdveltest.cpp)
target_link_libraries(cmdveltest ${catkin_LIBRARIES})

在src/cmdveltest.cpp内如如下

#include <iostream>
#include <geometry_msgs/Twist.h>
#include <ros/ros.h>
#include <ros/console.h>
#include<unistd.h>
using namespace std;
int main(int argc,char** argv)
{ros::init(argc, argv, "cmdveltest");ros::NodeHandle cmdh;ros::Publisher cmdpub= cmdh.advertise<geometry_msgs::Twist>("cmd_vel", 1, true);ros::Rate r(60);while(1){geometry_msgs::Twist twist;geometry_msgs::Vector3 linear;linear.x=0.1;linear.y=0;linear.z=0;geometry_msgs::Vector3 angular;angular.x=0;angular.y=0;//直行//angular.z=0;//转圈angular.z=-0.5;twist.linear=linear;twist.angular=angular;cmdpub.publish(twist);cout<<"hello"<<endl;// ros::spinOnce();//r.sleep();sleep(1);}return 0;
}

编译后启动 rosrun cmdveltest cmdveltest 发现机器人跑的飞起

启动命令过程

1.启动主程序

nvidia@tegra-ubuntu:~/catkin_ws/src/mbot_gazebo/launch$ roslaunch mbot_gazebo nav_gmapping_view_mbot_gazebolaserandcamera_room.launch 

2.启动rqt_graph查看节点

nvidia@tegra-ubuntu:~/catkin_ws/src/cmdveltest$ rqt_graph 

3.查看话题类型

nvidia@tegra-ubuntu:~/catkin_ws/src/cmdveltest$ rostopic list 

4.查看cmd_vel命令格式

nvidia@tegra-ubuntu:~/catkin_ws/src/mbot_gazebo/launch$ rostopic pub -r 10 /cmd_vel

5.启动cmd_vel程序

 rosrun cmdveltest cmdveltest

可以看到在rviz和gazebo软件中机器人在转圈