mateus03's profile - activity

@David Lu I've found out why A* gives a different path from Dijkstra. The issue is that you use the Manhattan distance has heuristic, if you use the Euclidean distance the paths will be almost identical.

@Andromeda. BennyRe is right. If you check the documentation for the visualization_msgs::MarkerArray, it contains only one field, Marker[] markers. This field is a vector of markers to store it just declare a std::vector of that type.

/* class #2: different from #1 */
...
ros::Subscriber array_sub = subscribe ("marker_topic", 5, &function, this );
...
std::vector<visualization_msgs::Marker> incoming_array;
...
void classname::function( const visualization_msgs::MarkerArray& msg ) {

if( !done ) {
  incoming_array = msg->markers; 
  done = true; 
 }
}

With that modification it should work.

Can you edit your question to add the main function?

Thank you! I'll check that

Hi all,

I'm working with some fisheye cameras mounted on the ceiling. What I want to do it them is to track people, get their position in the ground plane and an estimate on their speed. I've never worked with this kind of cameras before, does anyone have any idea on how to tackle this issue?

Thanks

Can you edit your question to show the error that you get?

If you just spawn the model in Gazebo you'll have the model in the simulator but you'll not be able to control it with ros. If you want to use the model in ros you should use roslaunch to spawn it, so the topics from odometry and the sensors are published.

Hi!

You should download a urdf model, since it will be simpler to just spawn it in gazebo. If you want to create your own model you can follow the tutorial gazebo build model. It explains how to build a simple mobile robot.

Hi!

Assuming that you implemented a plugin of BaseGlobalPlanner to plan your paths, you can just publish the plan to topic and then you can see the results in rviz. You just need to do

ros::NodeHandle private_nh("~/" + name);   
plan_pub_ = private_nh.advertise<nav_msgs::Path>("plan", 1);

And then implement a method to fill a nav_msgs::Path msg and publish it.

Thank you, it worked.

Hi all!

I'm trying do implement a base_global_planner plugin with RRT algorithm, for that I'm using the ompl package. The code compiles with no errors, and I followed the steps for registering the plugin but when I launch move_base I get the following error:

[FATAL] [1405968490.244759123, 1.315000000]: Failed to create the rrt_planner/RRT_Planner planner, are you sure it is properly registered and that the containing library is built? Exception: Failed to load library /home/mateus/catkin_ws/devel/lib/librrt_planner.so. Make sure that you are calling the PLUGINLIB_EXPORT_CLASS macro in the library code, and that names are consistent between this macro and your XML. Error string: Could not load library (Poco exception = /home/mateus/catkin_ws/devel/lib/librrt_planner.so: undefined symbol: _ZTVN4ompl4base13SO2StateSpaceE)

The macro is set as:

 PLUGINLIB_EXPORT_CLASS(rrt_planner::RRT_Planner, nav_core::BaseGlobalPlanner)

The xml file:

<library path="librrt_planner">
   <class name="rrt_planner/RRT_GlobalPlanner" type="rrt_planner::RRT_GlobalPlanner" base_class_type="nav_core::BaseGlobalPlanner">
    <description>
       A implementation of a grid based planner using RRT
    </description>
  </class>
</library>

CMakeLists

cmake_minimum_required(VERSION 2.8.3)
project(rrt_planner)

find_package(catkin REQUIRED COMPONENTS
  roscpp
  costmap_2d
  geometry_msgs
  nav_core
  nav_msgs
  pluginlib
  tf
  angles
)

find_package(
    ompl
)

find_package(Boost REQUIRED COMPONENTS system thread)

catkin_package(
  INCLUDE_DIRS include
  LIBRARIES rrt_planner 
  CATKIN_DEPENDS
    roscpp
    costmap_2d
    geometry_msgs
    nav_core
    nav_msgs
    pluginlib
    tf
    angles
  DEPENDS system_lib ompl
)

include_directories(
  include
  ${catkin_INCLUDE_DIRS}
  ${ompl_INCLUDE_DIRS}
)

add_library(rrt_planner
   src/rrt_planner.cpp
)

target_link_libraries(rrt_planner
   ${catkin_LIBRARIES}
   ${ompl_LIBRARIES}
)

The package.xml

<?xml version="1.0"?>

<package> <name>rrt_planner</name> <version>0.0.0</version> <description>The rrt_planner package</description>

<maintainer email="mateus@todo.todo">mateus</maintainer>

<license>TODO</license>

<buildtool_depend>catkin</buildtool_depend>
<build_depend>angles</build_depend>
<build_depend>boost</build_depend>
<build_depend>costmap_2d</build_depend>
<build_depend>eigen_conversions</build_depend>
<build_depend>geometry_msgs</build_depend>
<build_depend>nav_msgs</build_depend>
<build_depend>nav_core</build_depend>
<!--<build_depend>ompl</build_depend>-->
<build_depend>pluginlib</build_depend>
<build_depend>roscpp</build_depend>
<build_depend>tf</build_depend>

<run_depend>angles</run_depend>
<run_depend>boost</run_depend>
<run_depend>costmap_2d</run_depend>
<run_depend>eigen_conversions</run_depend>
<run_depend>geometry_msgs</run_depend>
<run_depend>nav_msgs</run_depend>
<run_depend>nav_core</run_depend>
<run_depend>ompl</run_depend>
<run_depend>pluginlib</run_depend>
<run_depend>roscpp</run_depend>
<run_depend>tf</run_depend>

<export>
  <nav_core plugin="${prefix}/rrt_planner_plugin.xml" />
</export>

</package>

I could not detect any error in the above code. So I think that the problem may be related with a warning I get when running catkin_make. The warning is the following:

WARNING: Package "ompl" does not follow the version conventions. It should not contain leading zeros (unless the number is 0).

Is my assumption correct? If so how can I solve that warning?

Ok, thank you

Thank you! Those resources were just what I needed to understand how to do this.