参考https://www.jianshu.com/p/682e80efbe5a
首先创建工作空间,创建工作空间
mkdir -p ~/test_ws/src
cd ~/test_ws
catkin_make
source devel/setup.bash
在～t/test_ws/src下创建功能包，创建功能包
catkin_create_pkg beginner_tutorials std_msgs roscpp rospy
在～/test_ws/src/beginner_tutorials中拷贝从/opt/ros/kinetic/share/turtlebot_stage中复制的maps文件夹
在～/test_ws/src/beginner_tutorials/src中创建sharemem.h文件，其中定义共享空间中的数据结构。文件内容为
#ifndef SHAREMEM_H
#define SHAREMEM_H
struct ShareMem
{
double x; // x方向的速度(前后)
double y; // y方向的速度(左右)
double z; // 旋转
};
#endif
新建talker节点。创建共享内存、监听共享内存区域的速度变化和发布速度话题。
/****************************************
*文件名: talker.cpp *
*简介: 链接非ROS进程和ROS节点的ROS节点 *
*BY: CR (qq: 414481619) *
*创建时间: 2018.10.09 *
****************************************/
#include "ros/ros.h"
#include <geometry_msgs/Twist.h>
#include <iostream>
#include <stdio.h>
#include <sys/shm.h>
#include <errno.h>
#include <sys/types.h>
#include <stdlib.h>
#include <pthread.h>
#include "sharemem.h"
using namespace std;
int main(int argc, char **argv)
{
ros::init(argc, argv, "talker");
ros::NodeHandle n;
ros::Publisher chatter_pub = n.advertise<geometry_msgs::Twist>("cmd_vel", 1000);
ros::Rate loop_rate(100); // 100Hz的定时器
ShareMem _ShareMem;
// 创建共享内存 ，相当于打开文件，文件不存在则创建
int shmid = shmget((key_t)2333, sizeof(_ShareMem), 0666|IPC_CREAT);
if(shmid==-1)
{
perror("shmget err");
return errno;
}
cout<<shmid<<endl;
// 将共享内存段连接到进程地址空间, 第二个参数shmaddr为NULL，核心自动选择一个地址
ShareMem *shareMem = (ShareMem *)shmat(shmid, NULL, 0);
if (shareMem == (void *)-1 )
{
perror("shmat err");
return errno;
}
shareMem->x = 0;
shareMem->y = 0;
shareMem->z = 0;
pthread_mutex_t mutex;
pthread_mutex_init(&mutex, NULL);
while (ros::ok())
{
geometry_msgs::Twist cmdvel_msg;
pthread_mutex_lock(&mutex);
cmdvel_msg.linear.x = shareMem->x;
cmdvel_msg.linear.y = shareMem->y;
cmdvel_msg.angular.z = shareMem->z;
pthread_mutex_unlock(&mutex);
chatter_pub.publish(cmdvel_msg);
ros::spinOnce();
loop_rate.sleep();
}
pthread_mutex_destroy(&mutex);
shmdt(shareMem); //将共享内存段与当前进程脱离
shmctl(shmid, IPC_RMID, NULL); //IPC_RMID为删除内存段
return 0;
}
在beginner_tutorials 的 CMakeLists.txt 中添加：
include_directories(include ${catkin_INCLUDE_DIRS})
add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})
在终端中：
cd ~/test_ws
catkin_make
创建launch文件新建launch文件夹，创建stage_tast.launch文件。
<!--
stage_test
- stage_ros
- talker
-->
<launch>
<arg name="world_file" default=" $(find beginner_tutorials)/maps/stage/maze.world"/>
<node pkg="stage_ros" type="stageros" name="stageros" args="$(arg world_file)">
<param name="base_watchdog_timeout" value="0.5"/>
<remap from="odom" to="odom"/>
<remap from="base_pose_ground_truth" to="base_pose_ground_truth"/>
<remap from="cmd_vel" to="cmd_vel"/>
</node>
<node pkg="beginner_tutorials" type="talker" name="talker">
</node>
</launch>
创建速度控制父类，便于其他速度控制类的编写，其他速度控制类只需要继承父类的框架，完成自己的mainloop()就好。
/****************************************
*文件名: VelControl.h *
*简介: 速度控制父类 *
*BY: CR (qq: 414481619) *
*创建时间: 2018.10.09 *
****************************************/
// this code ism't in ros system
#include <iostream>
#include <stdio.h>
#include <sys/shm.h>
#include <errno.h>
#include <sys/types.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include "sharemem.h"
using namespace std;
class VelControl
{
public:
VelControl();
~VelControl();
void mainloop();
protected:
ShareMem *shareMem;
pthread_mutex_t mutex;
void writeVel(double x, double y, double z);
};
VelControl::VelControl()
{
pthread_mutex_init(&mutex, NULL);
// 绑定共享内存
int shmid = shmget((key_t)2333, 0, 0);
if(shmid != -1)
{
shareMem =(ShareMem *)shmat(shmid, NULL, 0);
cout<<shmid<<endl;
}
else
{
cout<<"ERROR: stage_test haven't started"<<endl;
exit(1);
}
}
VelControl::~VelControl()
{
shmdt(shareMem); //将共享内存段与当前进程脱离
pthread_mutex_destroy(&mutex);
}
void VelControl::writeVel(double x, double y, double z)
{
pthread_mutex_lock(&mutex);
shareMem->x = x;
shareMem->y = y;
shareMem->z = z;
pthread_mutex_unlock(&mutex);
}
键盘控制例程
/****************************************
*文件名: keyboard_not_ros.cpp *
*简介: 速度控制例程 *
*BY: CR (qq: 414481619) *
*创建时间: 2018.10.09 *
****************************************/
// this code isn't in ros system
#include "VelControl.h"
using namespace std;
class keyboard_not_ros:VelControl
{
public:
void mainloop();
};
void keyboard_not_ros::mainloop()
{
char c = 'a';
while(c!='q')
{
cout<<"please input a letter"<<endl;
c = getchar();
getchar();
double x,y,z;
switch(c)
{
case 'W':
case 'w':
x = 1;
y = 0;
z = 0;
break;
case 'S':
case 's':
x = -1;
y = 0;
z = 0;
break;
case 'A':
case 'a':
x = 0;
y = 0;
z = 1;
break;
case 'D':
case 'd':
x = 0;
y = 0;
z = -1;
break;
default:;
}
writeVel(x, y, z);
usleep(100*1000);
writeVel(0,0,0);
}
}
int main(int argc, char const *argv[])
{
keyboard_not_ros k;
k.mainloop();
return 0;
}
编译程序，在 ~/test_ws/src/beginner_tutorials/src/ 目录下，终端输入：
g++ -o keyboard_not_ros keyboard_not_ros.cpp
启动launch文件
roslaunch beginner_tutorials stage_test.launch
另一个终端中，～/test_ws/src/beginner_tutorials/src下输入
./keyboard_not_ros
