The freespace_planner Package

freespace_planner_node

freespace_planner_node is a global path planner node that plans trajectory in the space having static/dynamic obstacles. This node is currently based on Hybrid A* search and RRT* algorithms in freesapce_planning_algorithms package.

Note Due to the constraint of trajectory following, the output trajectory will be split to include only the single direction path. In other words, the output trajectory doesn't include both forward and backward trajectories at once.

Input topics

Name	Type	Description
~input/route	autoware_planning_msgs::Route	route and goal pose
~input/occupancy_grid	nav_msgs::OccupancyGrid	costmap, for drivable areas
~input/twist	geometry_msgs::TwistStamped	vehicle velocity, for checking whether vehicle is stopped
~input/scenario	autoware_planning_msgs::Scenario	scenarios to be activated, for node activation

Output topics

Name	Type	Description
~output/trajectory	autoware_planning_msgs::Trajectory	trajectory to be followed
is_completed	bool (implemented as rosparam)	whether all split trajectory are published

Output TFs

None

How to launch

1. Write your remapping info in freespace_planner.launch or add args when executing roslaunch
2. roslaunch freespace_planner freespace_planner.launch

Parameters

Node parameters

Parameter	Type	Description
planning_algorithm	string	algorithm used in the node
collision_margin	double	collision margin
update_rate	double	timer's update rate
waypoints_velocity	double	velocity in output trajectory (currently, only constant velocity is supported)
th_arrived_distance_m	double	threshold distance to check if vehicle has arrived at the trajectory's endpoint
th_stopped_time_sec	double	threshold time to check if vehicle is stopped
th_stopped_velocity_mps	double	threshold velocity to check if vehicle is stopped
th_course_out_distance_m	double	threshold distance to check if vehicle is out of course
replan_when_obstacle_found	bool	whether replanning when obstacle has found on the trajectory
replan_when_course_out	bool	whether replanning when vehicle is out of course

Planner common parameters

Parameter	Type	Description
time_limit	double	time limit of planning
robot_length	double	robot length
robot_width	double	robot width
robot_base2back	double	distance from robot's back to robot's base_link
minimum_turning_radius	double	minimum turning radius of robot
theta_size	double	the number of angle's discretization
lateral_goal_range	double	goal range of lateral position
longitudinal_goal_range	double	goal range of longitudinal position
angle_goal_range	double	goal range of angle
curve_weight	double	additional cost factor for curve actions
reverse_weight	double	additional cost factor for reverse actions
obstacle_threshold	double	threshold for regarding a certain grid as obstacle

A* search parameters

Parameter	Type	Description
only_behind_solutions	bool	whether restricting the solutions to be behind the goal
use_back	bool	whether using backward trajectory
distance_heuristic_weight	double	heuristic weight for estimating node's cost

RRT* search parameters

Parameter	Type	Description
enable_update	bool	If true, refine solution path as possible after initial feasible path found within the given time budget time_limit. If false, the algorithm is almost equivalent of plane RRT
mu	double	neighbor radius in reeds-shepp space
margin	double	collision check margin internally used in RRT*'s collision check of continuous path, which does not appear in discrete search algorithm such as A*. Note that this margin is an extra margin on top of the collision_margin in the Node paramter.

Flowchart