RAPP Path planner

Components

1. rapp_path_planning

Rapp_path_planning is used in the RAPP case to plan path from given pose to given goal. User can costomize the path planning module with following parameters:

• pebuild map - avaliable maps are stored here,
• planning algorithm - for now, only dijkstra is avaliable,
• robot type - customizes costmap for planning module. For now only NAO is supported.

2. rapp_map_server

Rapp_map_server delivers prebuild maps to rapp_path_planning component. All avaliable maps are contained here.

This component is based on the ROS package: map_server. The rapp_map_server reads .png and .yaml files and publishes map as OccupacyGrid data. RAPP case needs run-time changing map publication, thus the rapp_map_server extands map_server functionality. The rapp_map_server enables user run-time changes of map. It subscribes to ROS parameter: rospy.set_param(nodeName+"/setMap", map_path) and publishes the map specified in map_path. Examplary map changing request is presented below.

nodename = rospy.get_name()
map_path = "/home/rapp/rapp_platform/rapp-platform-catkin-ws/src/rapp-platform/rapp_map_server/maps/empty.yaml"
rospy.set_param(nodename+/setMap, map_path)

A ROS service exists to store new maps in each user's workspace, called upload_map. Then each application can invoke the planPath2D service, providing the map's name (among others) as input argument.

ROS Services

Path planning

Service URL: /rapp/rapp_path_planning/planPath2D

Service type:

# Contains name to the desired map
string map_name
# Contains type of the robot. It is required to determine it's parameters (footprint etc.)
string robot_type
# Contains path planning algorithm name
string algorithm
# Contains start pose of the robot
geometry_msgs/PoseStamped start
# Contains goal pose of the robot
geometry_msgs/PoseStamped goal
---
# status of the service
# plan_found:
#          * 0 : path cannot be planned.
#          * 1 : path found 
#          * 2 : wrong map name
#          * 3 : wrong robot type
#          * 4 : wrong algorithm


uint8 plan_found
# error_message : error explanation
string error_message
# path : vector of PoseStamped objects
# if plan_found is true, this is an array of waypoints from start to goal, where the first one equals start and the last one equals goal
geometry_msgs/PoseStamped[] path

Service URL: /rapp/rapp_path_planning/upload_map

Service type:

# The end user's username, since the uploaded map is personal 
string user_name
# The map's name. Must be unique for this user
string map_name
# The map's resolution
float32 resolution
# ROS-specific: The map's origin
float32[] origin
# ROS-specific: Whether the occupied / unoccupied pixels must be negated
int16 negate
# Occupied threshold
float32 occupied_thresh
# Unoccupied threshold
float32 free_thresh
# File size for sanity checks
uint32 file_size
# The map data
char[] data
---
byte status

More information on the Occupancy Grid Map representation can be found here

Launchers

Standard launcher

Launches the path planning node and can be launched using

roslaunch rapp_path_planning path_planning.launch

#Web services

Path planning 2D

URL

localhost:9001/hop/path_planning_path_2d

Input / Output

Input = {
  "map_name": “THE_PRESTORED_MAP_NAME”,
  "robot_type": "Nao",
  "algorithm": "dijkstra",
  "start": {x: 0, y: 10},
  "goal": {x: 10, y: 0}
}

Output = {
  "plan_found": 0,
  "path": [{x: 0, y: 10}, {x: ... ],
  "error": ""
}

Upload map

URL

localhost:9001/hop/path_planning_upload_map

Input / Output

Input = {
  "png_file": “map.png”,
  "yaml_file": "map.yaml",
  "map_name": "simple_map_1"
}

Output = {
  "error": ""
}

The full documentation exists here and here.

Author

Wojciech Dudek