Hello,

Could you please re-post this question on answers.ros.org? Its a more accessible/easily searchable medium than this mailing list and others will more easily benefit from the answer to your question.

Hope all is well,

Eitan

On Thu, Jun 9, 2011 at 12:25 AM, GANESH KUMAR <pkganeshpk@gmail.com> wrote:
Hello,

I'm unable to get simple carrot planner code , for motion planning, up
and running.
The problem I'm trying to write code for is: to use carrot planner to
move the  erratic gazebo robot from a start point to end point.
Here are the problems I am facing:
(1) I doubt if my design is correct, or if there's a simpler way to
solve the above problem. Currently, I start erratic_wg.launch within
simulator_gazebo. Next, I have a tf::listener instance running in a
separate program, excerpts from which are given below. The listener
uses the carrot planner while transforming from base_link to map:
===
void transformPoint(const tf::TransformListener& listener)
{
         geometry_msgs::PointStamped laser_point;
         laser_point.header.frame_id = "base_link";
              ...
            tf::TransformListener mytf(ros::Duration(10));

         costmap_2d::Costmap2DROS costmap("my_costmap", mytf);
         carrot_planner::CarrotPlanner cp  ;
         cp.initialize("my_carrot_planner", &costmap);
         try
         {
                 geometry_msgs::PointStamped base_point;
                 listener.transformPoint("map", laser_point, base_point);

                 geometry_msgs::PoseStamped start  ;
                start.pose.position.x = 0 , start.pose.position.y = 0,
start.pose.position.z = 0;
                geometry_msgs::PoseStamped end;
                end.pose.position.x = 5 , end.pose.position.y = 5,
end.pose.position.z = 0;

                std::vector<geometry_msgs::PoseStamped> plan;
                cp.makePlan(start, end, plan);
                // SHould I send a cmd_vel message now for each step
of the plan?
        }
}
===

(2) When my costmap is initialized as above, the listener code
segfaults. I have traced this to the constructor of Costmap2DPublisher
called within Costmap2DROS constructor, but haven't gone deeper than
this.  I am using ros version  1.2.4 and the older version of the
navigation stack (i.e. which contained nav_view). I am not sure how to
specify the navigation stack version more precisely (i.e. repo
revision, etc.). Also, the latest navigation stack doesn't build , as
pcl_ros doesn't compile on my ros. So I stuck with a previous version
I had downloaded around Nov. 2010. I can provide further details if
necessary.

Thanks
PKG
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