Seems like a reasonable feature to expose. Applied the patch in r34304 in
navigation trunk. Should go into D-Turtle.
Thanks for passing it on,
Eitan
On Fri, Nov 26, 2010 at 3:35 AM, Christian Verbeek <
verbeek@servicerobotics.eu> wrote:
> Dear Eitan,
>
> I found it useful to enable navfn to be able to create a plan even if
> the goal position hits an obstacle. This is useful when you set goal
> positions through a user interface. If the user wants the robot to move
> near to walls or other obstacles then it is very likely that the goal
> position hits the obstacle and the robot does not move at all. Instead
> the intended behaviour is to get as close as possible and then stop if
> the robots sensors detect an obstacle.
>
> I modified nafvn_ros to clear a region in the costmap around the goal
> position before making the plan. This behaviour must be switched on by
> setting the clear_goal_position parameter to true (default is false
> keeping everything as before).
>
> What do you think? Could this be integrated into the ros mainstream?
> Would make things easier for me.
>
> The patch is generated from stacks/navigation/navfn
>
> Best wishes
> Christian
>
> Index: include/navfn/navfn_ros.h
> ===================================================================
> --- include/navfn/navfn_ros.h (revision 34269)
> +++ include/navfn/navfn_ros.h (working copy)
> @@ -132,7 +132,7 @@
> boost::shared_ptr<NavFn> planner_;
> double inscribed_radius_, circumscribed_radius_, inflation_radius_;
> ros::Publisher plan_pub_;
> - bool initialized_, allow_unknown_;
> + bool initialized_, allow_unknown_, clear_goal_position_;
>
>
> private:
> Index: src/navfn_ros.cpp
> ===================================================================
> --- src/navfn_ros.cpp (revision 34269)
> +++ src/navfn_ros.cpp (working copy)
> @@ -64,9 +64,10 @@
> plan_pub_ = private_nh.advertise<nav_msgs::Path>("plan", 1);
>
> private_nh.param("allow_unknown", allow_unknown_, true);
> + private_nh.param("clear_goal_position", clear_goal_position_,
> false);
> private_nh.param("planner_window_x", planner_window_x_, 0.0);
> private_nh.param("planner_window_y", planner_window_y_, 0.0);
> -
> +
> double costmap_pub_freq;
> private_nh.param("planner_costmap_publish_frequency",
> costmap_pub_freq, 0.0);
>
> @@ -252,17 +253,33 @@
> tf::poseStampedMsgToTF(start, start_pose);
> clearRobotCell(start_pose, mx, my);
>
> - //make sure to resize the underlying array that Navfn uses
> - planner_->setNavArr(costmap_.getSizeInCellsX(),
> costmap_.getSizeInCellsY());
> - planner_->setCostmap(costmap_.getCharMap(), true, allow_unknown_);
> -
> int map_start[2];
> map_start[0] = mx;
> map_start[1] = my;
>
> - wx = goal.pose.position.x;
> + wx = goal.pose.position.x;
> wy = goal.pose.position.y;
>
> + if( clear_goal_position_ )
> + {
> + //clear goal cell to be able to plan even if the goal is within
> an obstacle
> + for( float x = wx - inscribed_radius_; x <= wx +
> inscribed_radius_; x += costmap_.getResolution() )
> + {
> + for( float y = wy - inscribed_radius_; y <= wy +
> inscribed_radius_; y += costmap_.getResolution() )
> + {
> + if(!costmap_.worldToMap(x, y, mx, my)){
> + ROS_WARN("The goal sent to the navfn planner is off
> the global costmap. Planning will always fail to this goal.");
> + return false;
> + }
> + costmap_.setCost(mx, my, costmap_2d::FREE_SPACE);
> + }
> + }
> + }
> +
> + //make sure to resize the underlying array that Navfn uses
> + planner_->setNavArr(costmap_.getSizeInCellsX(),
> costmap_.getSizeInCellsY());
> + planner_->setCostmap(costmap_.getCharMap(), true, allow_unknown_);
> +
> if(!costmap_.worldToMap(wx, wy, mx, my)){
> ROS_WARN("The goal sent to the navfn planner is off the global
> costmap. Planning will always fail to this goal.");
> return false;
>
> --
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