问题描述
目前,我有一个必须同时拥有订阅者和发布者的节点。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;
}
在调试这些错误方面的任何帮助将不胜感激。谢谢
解决方法
对于味精,你应该使用:
msg->ranges[360]
并且由于“pub”是在您的主函数中声明的,因此您不能在不同的函数中调用它。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;
}
另外,检查你的 package.xml 和 CMakeLists.txt
请参阅 http://wiki.ros.org/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29 中的第 3 节(构建您的节点)