<> <> ## AUTOGENERATED DON'T DELETE ## CategoryPackage Please check the <> for common problems, or open an [[https://github.com/paulbovbel/frontier_exploration/issues|issue]] if still unsolved. == Overview == The best way to try `frontier_exploration` is using the demo provided in [[husky_navigation]], see the [[husky_navigation/Tutorials/Husky Frontier Exploration Demo|demo tutorial]]. === Functionality === The `frontier_exploration` package provides a [[costmap_2d]] layer plugin `BoundedExploreLayer`, and [[actionlib]] client/server nodes `explore_client` and `explore_server`. The provided nodes can be used to demo the functionality of the costmap layer by executing a frontier exploration task bounded by a user-defined polygon area. Layer `BoundedExploreLayer` can certainly be used for more complex exploration tasks, functionality is exposed through two [[Services]]: `UpdatePolygonBoundary` and `GetNextFrontier`. <> To run this demo on your host, see [[frontier_exploration#For_running_a_demo]] section. Also, this video is an example of `frontier_exploration` integrated with [[turtlebot|Turtlebot]] ([[https://github.com/130s/turtlebot_samples|turtlebot_samples package is used]]). <> === Requirements === Frontier exploration using this package requires a real or simulated robot configuration that provides the following functionality: 1. Laser scanner or similar sensor that can clear space and mark obstacles. 2. Properly configured [[navigation]] stack that can accept action goals to [[move_base]]. 3. (Optional) Global `/map` provided by [[map_server]], [[gmapping]], or the global costmap from [[move_base]] == Usage == === For running a demo === Using a pre-existing robot and config, you can run a demo and see how this package works. 1. Install dependency. {{{ sudo apt-get install ros-$ROS_DISTRO-frontier-exploration ros-$ROS_DISTRO-navigation-stage }}} 2. Run the necessary nodes one-by-one from separate terminal: {{{ roslaunch navigation_stage move_base_gmapping_5cm.launch roslaunch navigation_stage move_base.xml roslaunch frontier_exploration global_map.launch }}} RViz pops up, then a demo robot appears around the center in a map. 3. Open a `Marker plugin` on RViz (RViz plugins can be chosen in a popup window that you can open by "Add" button). 4. Pull down "`Displays --> Marker --> Marker Topic`" menu then select "`exploration_polygon_marker`" topic. 5. On the map on RViz, think of a region that you like the robot to explore. 6. Click "`Publish Point`" at the top of RViz. 7. Click **a single corner** of `n` corners of the region (n=4 if your region is square/rectangular, to be pedantic)． 8. Repeat step 6 and 7 above for n times. After that you'll see a polygon with n corners. 9. Do the step 6 once again, then this time click anywhere within the polygon. At this point the demo robot should start moving [[https://youtu.be/3W1ufJ7rpCA|as the video above]]. === For developers === If you just want to start taking advantage of the functionality of this package, [[husky_navigation/Tutorials/Husky Frontier Exploration Demo|this tutorial in husky_navigation package]] helps. If you like to understand a little more in depth, generally, when launched `explore_server` will spin until it receives an exploration goal. To submit a goal: 1. Use `explore_client` and RViz - create a marker display in Rviz for the `exploration_polygon_marker` topic, and use the "Click Point" tool from the toolbar to mark the exploration boundary. Watch the ROS console for feedback regarding your selected boundary. 2. Submit a goal to the server with your own node via an [[actionlib]] SimpleActionClient. The exploration goal contains an initial point to start exploration, and a polygonal boundary to limit the exploration scope. To run an unbounded exploration task, simply leave the boundary blank. Once the server receives a goal, it will create the initial exploration map, start processing sensor/costmap data, and issuing `move_base` action goals. By default, the exploration task will explore all areas within boundary (whether previously visited or not). Sample launch files for several use cases are provided below. ==== Exploration without /map data ==== When running the action server/client without a global `/map` information source, enable the `resize_to_boundary` parameter to dynamically resize the map based on the action goal's polygon boundary. Error messages thrown up by `costmap_2d` regarding the sensor being outside of map bounds will occur when the robot is traveling outside the exploration boundary. These can be safely ignored, and could be suppressed using `rosconsole` configuration files. If not using `resize_to_boundary` (e.g. running unbounded exploration), make sure the costmap is configured with a large enough height/width. Sample launch file: [[https://github.com/paulbovbel/frontier_exploration/blob/hydro-devel/launch/no_global_map.launch|no_global_map.launch]] ==== Exploration with /map data ==== When running the action server/client with a global `/map` information source (either from `map_server` or `gmapping`), the exploration costmap will match size/resolution to the external map source map loaded by the static layer, so it is important to disable the `resize_to_boundary` parameter and that the `global_frame` of the exploration costmap matches that of the external /map. When exploring with `gmapping`, you must also disable `explore_clear_space` to prevent the node from re-exploring known areas. Sample launch file: [[https://github.com/paulbovbel/frontier_exploration/blob/hydro-devel/launch/global_map.launch|global_map.launch]] == Provided Components == {{{ #!clearsilver CS/NodeAPI name = explore_client desc = The `explore_client` node listens to points published by Rviz and builds an `ExploreTask` action goal to send to `explore_server`. act_called { 0.name= explore_server 0.type= frontier_exploration/ExploreTask 0.desc= Client for exploration goals to `explore_server`. } sub { 0.name = /clicked_point 0.type = geometry_msgs/PointStamped 0.desc = Clicked points from [[rviz]] tool. } pub{ 0.name = exploration_polygon_marker 0.type = visualization_msgs/Marker 0.desc = Boundary visualization via clicked points. } }}} === explore_server === The `explore_server` node executes exploration actions for any connected clients. It uses a [[costmap_2d]] object to keep track of the exploration progress, and creates movement goals for [[move_base]] as necessary. ==== Actions Provided ==== {{{ #!clearsilver CS/NodeAPI act_called { no_header= True 0.name= explore_server 0.type= frontier_exploration/ExploreTask 0.desc= Server for incoming exploration task requests } }}} {{{ #!clearsilver CS/NodeAPI act_called { 0.name= move_base 0.type= move_base_msgs/MoveBaseAction 0.desc= Client for movement goals to `move_base`. } srv_called { 0.name= ~explore_costmap/explore_boundary/update_boundary_polygon 0.type= frontier_exploration/UpdateBoundaryPolygon 0.desc= (Internal Service from Costmap) Set boundary for exploration task. 1.name= ~explore_costmap/explore_boundary/get_next_frontier 1.type= frontier_exploration/GetNextFrontier 1.desc= (Internal Service from Costmap) Get the pose of the next frontier to explore. } param { 0.name = ~explore_costmap 0.type = plugins 0.desc = Configuration for internal costmap layers, expected to include `BoundedExploreLayer`. 1.name = ~frequency 1.type = float 1.desc = Frequency with which to reprocess the costmap for next frontier goal. If `0.0`, only ask for new frontier when last frontier was reached via `move_base`. Higher frequencies submit `move_base` goals more often and create 'smoother' exploration. 1.default = 0.0 2.name = ~goal_aliasing 2.type = float 2.default = 0.1 2.desc = When `frequency` > `0.0`, `~goal_aliasing` is the required distance delta between the last goal and a new goal, before the new goal is submitted to `move_base`. It is safe to set to anywhere within `sensor_range/2` > `~goal_aliasing` > `0.0`, and this parameter will reduce the amount of redundant goals sent during 'smooth' exploration. } }}} {{{ #!clearsilver CS/NodeAPI name = BoundedExploreLayer desc = The `frontier_exploration::BoundedExploreLayer` layer is a costmap_2d plugin that implements several functions required to execute a frontier exploration task. srv { 0.name= ~update_boundary_polygon 0.type= frontier_exploration/UpdateBoundaryPolygon 0.desc= Set boundary for exploration task. 1.name= ~get_next_frontier 1.type= frontier_exploration/GetNextFrontier 1.desc= Get the pose of the next frontier to explore. } param { 0.name = ~resize_to_boundary 0.type = bool 0.desc = When receiving a polygonal boundary via `~update_boundary_polygon`, resize the layer's parent costmap to the boundary extrema. 0.default = false 1.name = ~frontier_travel_point 1.type = string 1.desc = When outputting `pose` of next frontier via `~get_next_frontier`, define the geometric property of frontier to output as `pose.position`. Available: `closest` point to robot, `middle` point of frontier, `centroid` (cartesian average) of all frontier points. 1.default = closest 2.name = ~explore_clear_space 2.type = bool 2.desc = Configure whether the exploration task should explore all clear space (true), or just unknown space (false). 2.default = true } pub { 0.name = ~frontiers 0.type = sensor_msgs/PointCloud2 0.desc = Pointcloud `pcl::Pointcloud` marking all frontiers detected when service `~get_next_frontier` is called, with the selected frontier marked using a higher intensity point. } }}}