在同一节点中同时拥有订阅者和发布者的问题
Issues with having both subscriber and publisher in the same node
目前,我有一个节点必须同时具有订阅者和发布者。但是,我在构建catkin时遇到了某些错误。
#include <geometry_msgs/Twist.h>
#include <ros/ros.h>
#include <sensor_msgs/LaserScan.h>
#include <std_msgs/Float32.h>
void laserCallBack(const sensor_msgs::LaserScan::ConstPtr &msg) {
geometry_msgs::Twist reply;
if (msg.ranges[360] >= 1.0) {
reply.linear.x = 0.5;
reply.angular.z = 0.0;
pub.publish(reply);
} else if (msg.ranges[360] < 1.0) {
reply.linear.x = 0.0;
reply.angular.z = 0.5;
pub.publish(reply);
}
}
int main(int argc, char **argv) {
ros::init(argc, argv, "topics_quiz_node");
ros::NodeHandle nh;
ros::Publisher pub = nh.advertise<geometry_msgs::Twist>("/cmd_vel", 1000);
ros::Subscriber sub = nh.subscribe("/kobuki/laser/scan", 1000, laserCallBack);
ros::spin();
return 0;
}
报错如下: Errors
如能帮助调试这些错误,我们将不胜感激。谢谢
对于消息你应该使用:
msg->ranges[360]
并且由于“pub”是在您的主函数中声明的,因此您不能在其他函数中调用它。可以先全局声明,在main函数中初始化。
例如:
#include <geometry_msgs/Twist.h>
#include <ros/ros.h>
#include <sensor_msgs/LaserScan.h>
#include <std_msgs/Float32.h>
ros::Publisher pub;
void laserCallBack(const sensor_msgs::LaserScan::ConstPtr &msg) {
geometry_msgs::Twist reply;
if (msg->ranges[360] >= 1.0) {
reply.linear.x = 0.5;
reply.angular.z = 0.0;
pub.publish(reply);
} else if (msg->ranges[360] < 1.0) {
reply.linear.x = 0.0;
reply.angular.z = 0.5;
pub.publish(reply);
}
}
int main(int argc, char **argv) {
ros::init(argc, argv, "topics_quiz_node");
ros::NodeHandle nh;
pub = nh.advertise<geometry_msgs::Twist>("/cmd_vel", 1000);
ros::Subscriber sub = nh.subscribe("/kobuki/laser/scan", 1000, laserCallBack);
ros::spin();
return 0;
}
此外,请检查您的 package.xml 和 CMakeLists.txt
请参阅 http://wiki.ros.org/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29
中的第 3 部分(构建您的节点)