sfm_local_controller

A robot local controller based on the Social Force Model (SFM) (https://github.com/robotics-upo/lightsfm). A set of attractive and repulsive forces determine the behavior of the planner.

This local planner has been programmed as a BaseLocalPlanner plugin. So it can be used in the ROS move_base architecture. Although It receives a local costmap from move_base, the costmap is not used and a dedicated collision detector is employed instead. This detector uses laserscan input to check the possible collisions.

Acknowledgment

This work has been financed by the European Regional Development Fund (FEDER) and by the Ministry of Economy, Knowledge, Business and University, of the Government of Andalucía , within the framework of the FEDER Andalucía 2014-2020 operational program. Specific objective 1.2.3. "Promotion and generation of frontier knowledge and knowledge oriented to the challenges of society, development of emerging technologies" within the framework of the reference research project UPO-1264631. FEDER co-financing percentage 80%

Parameters

• Robot Configuration Parameters

  • max_lin_acc. Maximum acceleration in translation (m/s^2).
  • max_rot_acc. Maximum acceleration in rotation (rad/s^2).
  • max_lin_vel. Maximum linear velocity (m/s).
  • min_lin_vel. Minimum linear velocity (m/s).
  • max_rot_vel. Maximum angular velocity (rad/s).
  • min_rot_vel. Minimum angular velocity (rad/s).
  • min_rot_in_place. Angular velocity of rotations in place (rad/s).
  • a. A factor that determines the angular velocity when the robot is turning. (Def: 10.0).
  • planner_frame. The frame in which the controller works. (Def: "odom").
  • robot_frame. The robot base frame. (Def: "base_link").
  • robot_radius. Radius (m) of the approximated circumference of the robot footprint.
  • people_radius. Radius (m) of the approximated circumference that circumscribe a human footprint. (Def: 0.35).

• Goal Tolerance Parameters

  • goal_tolerance. Tolerance in euclidean distance (m) to consider that the goal has been reached.
  • yaw_tolerance. Tolerance in angular distance (rad) to consider that the goal has been reached.
  • local_goal_dist. Distance (m) from the robot to look for a local goal in the global path (Def: 1.0).

• Sensor Interface Parameters The sensor interface is in charge of taking the sensory input and update the information of the surrounding social agents in the scene.

  • laser_topic. Topic in which the laser range finder is being published [sensor_msgs/LaserScan].
  • people_topic. Topic in which the people detected are being published [people_msgs/People].
  • dyn_obs_topic. Topic in which the dynamic obstacles detected are being published [dynamic_obstacle_detector/DynamicObstacles].
  • odom_topic. Odometry topic [nav_msgs/Odometry].
  • max_obstacle_dist. Maximum distance (m) in which the obstacles are considered for the social force model.
  • naive_goal_time. Lookahead time (secs) to predict an approximate goal for the pedestrians.
  • people_velocity. Average velocity of the pedestrians (m/s).

• Social Force Model Parameters

  • sfm_goal_weight. Weight of the attraction force to the goal.
  • sfm_obstacle_weight. Weight of the respulsive force of the obstacles.
  • sfm_people_weight. Weight of the respulsive force of the pedestrians.

• Collision Checker Parameters

  • use_laser. Boolean to indicate whether to use a laser scan for input. The scan topic indicated in the previous parameter laser_topic will be used. (Def: True).
  • use_range. Boolean to indicate whether to use sonar ranges for collision detection. If True, the topic names of the different sonars must be indicated by the parameters range_topic_X in which the X must be replaced by a number. eg: range_topic_0, range_topic_1*, etc. (Def: False).
  • sensor_uncertainty. Uncertainty or accurary of the sensory input (m). (Def: 0.05).

Publications

Besides the publications of the commands and paths according to the move_base structure. The planner publishes some RViz markers:

• /sfm/markers/goal [visualization_msgs/Marker]. Arrow with the local goal of the controller.

• /sfm/markers/robot_forces [visualization_msgs/MarkerArray]. Vectors with the different forces of the SFM.

Dependencies

• dynamic_obstacle_detector (https://github.com/robotics-upo/dynamic_obstacle_detector).

• lightsfm (https://github.com/robotics-upo/lightsfm)