[ros-users] Motion planning using carrot planner

GANESH KUMAR pkganeshpk at gmail.com
Thu Jun 9 07:25:16 UTC 2011


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);
                 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


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