farhatm's profile - activity

Hey together,

I am trying to simulate Hector_slam using gazebo in a Outdoor situation, This means the objects are far apart, i am using a Robot with 2D Hokuyo LiDAR and IMU. when I drive the Robot around everything look fine. But when i change the direction or the object are fare away, than the /slam_out_pose change the position and it is no longer connected to my robot and than my map is broken.I have no idea why and why my IMU does not stabilize my simulation.

I upload in my Dropbox(see Link below), some information should help to solve my Problem( I hope)

• bag file
• rqt_graph
• frame
• Some pictures

Dropbox Link -> link text

maybe i miss somthing in my launch file.

thanks.

did you get any errors when you launch it? can you run: rosrun rqt_graph rqt_graph and rosrun rqt_tf_tree rqt_tf_tree after you launch the cartographer node, and post the result.

Hey,

I am using 3D google cartographer and the /cartographer_node publish a /submap_list and this topic has a cartographer_ros_msgs/SubmapList. How can I save my created map? I tried

rosrun map_server map_saver -f mymap

but it did not work (because I need another topic). Any idea. Thx

There were no problems, I have not waited enough. My laptop is not fast enough to use 3d SLAM.

yes, I try it, I can seen Odom at the top and than base_link and the 2 Sensor at the bottom. But I c'ant see the map frame. Like I said before the 2D node work without problems, only the 3d node. did you have any idea? thx

Actually everything is set right like in this page, I've checked it a couple of times map_frame = "map", I wonder why the Frame [map] does not exist, If I will use it to create a map.

Hey,

I have a VLP-16 - Velodyne LiDAR (3d LiDAR) that publish a pointCloud2 /horizontal_laser_3d msg and a IMU that publish a /imu. I change the conficuration in the backpack_3d.lua. when I start cartographer_node I get this error message in rviz (submaps):

For frame [map]: Frame [map] does not exist. But wehn i use a 2D LiDAR and the 2D cartographer node everything work fine. I know that, I d'ont have a transform between odom and map but why? any idea how can i fix this error?

Thanks

Hey, you need a IMU topic that publich /imu msg. I d'ont know, if you can use it only with /scan and /odom topic you have to change the configuration in your backpack_2d.lua.

use_laser_scan = true, use_multi_echo_laser_scan = false,

read this: https://google-cartographer-ros.readt...

Yes i know. I asked the same question in Gazebosim forum. but maybe someone has any idea here.

Hey,

is there any 3D LiDAR sensors in Gazebo which publish a pointcloud2 msg to ROS?

thx a lot

Hey,

I'm trying to use google cartographer to create a 2d Map but i have some problem. I use gazebo to simulate it. I tried gmapping and Hector_slam before and i had no problem to creat a map. Then I add a IMU plugin to my Robot like this:

 <gazebo>
<plugin name="imu_plugin" filename="libgazebo_ros_imu.so">
  <alwaysOn>true</alwaysOn>
  <bodyName>imu_link</bodyName>
  <topicName>imu</topicName>
  <serviceName>imu_service</serviceName>
  <!--gaussianNoise>0.0</gaussianNoise-->
  <updateRate>20.0</updateRate>
</plugin>
</gazebo>

and i change the some parameter in the configuration file backpack_2d.lua :

    tracking_frame = "chassis",
    published_frame = "imu_link",
    use_odometry = false,
    use_laser_scan = true,
    use_multi_echo_laser_scan = false,

and then i start the /cartographer_node. Somehow the robot start to jump in rviz and Creat a wrong map. I think that my problem is because my IMU. i tried to solve it but without success I am very grateful if someone can help me. I have tried to add some picture "rosgraph", frame and rviz but i cant.

Thanks, now it works :)

No, I d'ont get any error. but my problem is when i use

rostopic echo /horizontal_laser_2d

nothing change in the variable in my msg. my problem is i d´ont know how to use

pub_.publish(output);

so i can publich the msg right my node publich only 0

Hello,

I have a node that publish /scan topic and this topic has the massage type sensor_msgs/LaserScan.msg. another node can only subscribe sensor_msgs/MultiEchoLaserScan.msg massage type. The two massage type are very similar only ranges and intensities are different.

I thought I'd make a new node and this node convert the msg. My problem is, i have now idea how can i publich my convert message again. this code is my node "convert_LaserScan_to_MultiEchoLaserScan":

#include "ros/ros.h"
#include "std_msgs/String.h"
#include "sensor_msgs/LaserScan.h"
#include "sensor_msgs/MultiEchoLaserScan.h"

class convert_LaserScan_to_MultiEchoLaserScan
 {
 public:
 convert_LaserScan_to_MultiEchoLaserScan()
  {
 //Topic you want to publish
  pub_ = n_.advertise<sensor_msgs::LaserScan>("/horizontal_laser_2d", 1000);

//Topic you want to subscribe
  sub_ = n_.subscribe("/scan", 1000, &convert_LaserScan_to_MultiEchoLaserScan::callback, this);
 }


 void callback(const sensor_msgs::LaserScan::ConstPtr& input)
{
sensor_msgs::LaserScan output;

sensor_msgs::MultiEchoLaserScan muls;
for (int i = 0; i < input->ranges.size(); ++i) {
    const float &range = input->ranges[i];
    ROS_INFO("ranges: [%f]",range);
    sensor_msgs::LaserEcho echo;
    echo.echoes.push_back(range);
    muls.ranges.push_back(echo);

}

pub_.publish(output);
 }

  private:
  ros::NodeHandle n_;
  ros::Publisher pub_;
  ros::Subscriber sub_;

  };//End of class convert_LaserScan_to_MultiEchoLaserScan


  int main(int argc, char **argv)
 {  
  //Initiate ROS
  ros::init(argc, argv, "convert_LaserScan_to_MultiEchoLaserScan");

  //Create an object of class SubscribeAndPublish that will take care of everything
  convert_LaserScan_to_MultiEchoLaserScan SAPObject;

  ros::spin();



  return 0;
}

I am grateful for your help