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Documentation

The MRRP uses a prioritized planning approach to find the robots routes. Additionally, there are a Priority and a Speed Rescheduler as well as a Collision resolver integrated to solve special scenarios not solvable by standard prioritized planning approaches as shown in the figure below.

The route can be used for multiple vehicles or for just one to plan paths on a given or generated graph.

Multi Robot Mode

The Multi Robot Mode is the default mode. The planner listens to /robot_info see how many robots are online and available for planning. A list of goals can be send to goal Since the results generated for these scenarios are interdependent, the given routes have to be executed in a synchronized fashion. Therefore, the Router publishes a tuw_multi_robot_msgs/Route containing preconditions, when a robot is allowed to enter a segment. Additionally a unsynchronized version via nav_msgs/Path is published for every robot.

Single Robot Mode

In this mode the planner just plans a path for one robot but on a graph which is faster and depending how the graph was generated saver to drive e.g. on a voronoi graph the path would always be center in the hallway and not cut corners such as A-star. In order to activae this mode have a look on the paramter path_endpoint_optimization and robot_name.

Example

For an example see the tuw_multi_robot_demo package.

Subscribed Topics

/robot_info (tuw_multi_robot_msgs/RobotInfo)

• Every robot should publish its state /robot_info. This is required to let the node know how many robots are available and their location for planning in order to genrerate the a publisher for each robot

map (nav_msgs/OccupancyGrid)

• The map used for planning.

segments (tuw_multi_robot_msgs/Graph)

• A list of tuw_multi_robot_msgs/Vertex describing the voronoi path or an arbitrary hand crafted segment path.

goals (tuw_multi_robot_msgs/RobotGoalArray)

• The list of desired robot goals.

/goal (geometry_msgs/PoseStamped)

• Exists only in single robot mode to send a goal for one robot

Published Topics

planner_status (tuw_multi_robot_msgs/PlannerStatus)

• The status of the planner for debugging.

[robot_name]/path (nav_msgs/Path)

• A unsynchronized path msg for every robot. [robot_name] defines namespace of each registed robot via /robot_info

[robot_name]/route (tuw_multi_robot_msgs/Route)

• A synchronized route for every robot containing segment preconditions.

Parameters

robot_name (string default: "")

• defines a single robots name to active the single robot mode.

RQT Reconfigure Parameters

voronoi_graph (bool default: "true")

• If the graph is generated using the voronoi graph generator this can save computation time. (Additionally it can be checkt if the graph covers the whole free space of the map)

priority_rescheduling (bool default: "true")

• Enables priority rescheduling

speed_rescheduling (bool default: "true")

• Enables speed rescheduling

router_time_limit_s (float default: "10.0")

• Sets the timelimit for the planning approach. (Only for planning)

topic_timeout_s (float default: "10.0")

• Sets the timelimit for deleting latched topics.

path_endpoint_optimization (bool default: "false")

• Only used if exactly one robot is used for planning. Removes an appropriate amount of endsegments of the path to get shorter routes.

collision_resolver (enum default: "Avoidance")

• Enum to select the backtracking strategy to avoid blocking robots.
• Avoidance: allows robot to avoid other ones in crossings and wait on a spot.
• Backtracking: allows robots to wait in a certain spot for other ones.
• None: Standard A-Star planner

goal_mode (enum default: "use_voronoi_goal")

• Selects where the last segment is connected to.

router_type (enum default: "standard_router")

• Selects the router type
• standard_router: A straight forward none multi threaded router
• threaded_router_srr: Multi Threaded router which plans every robots route in a single thread. (similar to todo)

nr_threads (int default: "1")

• selects the number of threads used for all multi threaded routers

Report a Bug

Use GitHub to report bugs or submit feature requests. [View active issues]