ROS小车移动固定距离or转向固定角度（自用）

网上找的例程，根据实际需要做了修改

#include 
#include 
#include 
#include 

ros::Publisher cmdVelPub;

void shutdown(int sig)
{
  cmdVelPub.publish(geometry_msgs::Twist());//ctrl+c
  ROS_INFO("goforward cpp ended!");
  ros::shutdown();
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "GoForward");//int ros
  std::string topic = "/cmd_vel";
  ros::NodeHandle node;
  cmdVelPub = node.advertise<geometry_msgs::Twist>(topic, 1);
//=========================
  double rate = 10 ;
  ros::Rate loopRate(rate);
  float linear_speed 	= 0.2;
  float goal_distance 	= 1.0;
  float linear_duration = goal_distance / linear_speed;

  float angular_speed	= 1.0;
  float goal_angle	= M_PI;
  float angular_duration= goal_angle / angular_speed;

  int count = 0;
  int ticks;
//================================
  signal(SIGINT, shutdown);
  ROS_INFO("goforward cpp start...");
  geometry_msgs::Twist speed; 
//================================
  while (ros::ok())
  {
	speed.linear.x = linear_speed;
	ticks = int(linear_duration*rate);
    	for(int i = 0;i<ticks; i++)
	{
	cmdVelPub.publish(speed);
	loopRate.sleep();
	}
	 cmdVelPub.publish(geometry_msgs::Twist());
   	 ROS_INFO("detect arm...!");
	// stop&catch
   	speed.linear.x = 0;
	ticks = int(linear_duration*rate);
    	for(int i = 0;i<ticks; i++)
	{
	cmdVelPub.publish(speed);
	loopRate.sleep();
	}
	cmdVelPub.publish(geometry_msgs::Twist());
	  ROS_INFO("run again");
	//run again
	speed.linear.x = linear_speed;
	ticks = int(linear_duration*rate);
    	for(int i = 0;i<ticks; i++)
	{
	cmdVelPub.publish(speed);
	loopRate.sleep();
	}
	speed.linear.x = 0;
	cmdVelPub.publish(geometry_msgs::Twist());
	ROS_INFO("stop");
  }

  return 0;
}