sbpl_lattice_planner

The sbpl_lattice_planner is a global planner plugin for move_base and wraps the SBPL search-based planning library.

Paths are generated by combining a series of “motion primitives” which are short, kinematically feasible motions. Planning is therefore done in x, y, and theta dimensions, resulting in smooth paths that take robot orientation into account, which is especially important if the robot is not assumed to be circular or has nonholonomic constraints (e.g., the robot cannot move sideways). Plans can be found using the ARA* planner or AD* planner from the SBPL library.

Video

How to use

This global planner can be used with move_base simply by setting the base_global_planner parameter to SBPLLatticePlanner. Additionally, at the very least the path to a motion primitive file must be specified shown below in the list of parameters.

Example in Stage

The package contains a launch file for testing the sbpl_lattice_planner as the global planner for move_base using stage for 2D simulation:

roslaunch sbpl_lattice_planner move_base_sbpl_fake_localization_2.5cm.launch

ROS API

Published Topics

~/SBPLLatticePlanner/plan (nav_msgs/Path)

• The last plan computed by SBPL, published every time the planner computes a new path, and used primarily for visualization purposes.

~/SBPLLatticePlanner/sbpl_lattice_planner_stats (sbpl_lattice_planner/SBPLLatticePlannerStats)

• Statistics from the last planning request. Stats include: time taken to get to the first and final solutions, number of state expansions taken to get the first and final solutions, the epsilon (bound on the sub-optimality of the solution) of the first and final solutions, and the size of the final solution.

Subscribed Topics

None

Services

None

Parameters

~/SBPLLatticePlanner/planner_type (string, default: “ARAPlanner”)

• Specifies which planner to use. It can either be “ARAPlanner” for ARA* or “ADPlanner” for AD*.

~/SBPLLatticePlanner/allocated_time (double, default: 10.0)

• The amount of time given to the planner to find a solution. If there is still time remaining after the planner finds its sub-optimal initial solution (specified by “initial_epsilon”), the planner will use up remaining time improving the solution until it is optimal or until time runs out (whichever comes first).

~/SBPLLatticePlanner/initial_epsilon (double, default: 3.0)

• The value the heuristic is scaled by for the first search. This value must be greater or equal to 1. The larger this value is, the faster the search tends to find a solution (likely sub-optimal if epsilon is larger than 1). After the first search, the planner will continue to reduce the epsilon value until it is 1 (optimal search).

~/SBPLLatticePlanner/environment_type (string, default: “XYThetaLattice”))

• The type of environment being searched. Currently, XYThetaLattice is the only supported environment.

~/SBPLLatticePlanner/forward_search (bool, default: false)

• The direction the search is done in. If you are using AD*, you should use backward search for fast replanning times. For ARA* it doesn’t matter too much which direction you use.

~/SBPLLatticePlanner/primitive_filename (string, default: “”)

• The path to a motion primitive file. This MUST be specified by the user for the planner to work. There is an example motion primitive file that can be used in matlab/mprim/pr2.mprim in the SBPL package. If you want to generate your own motion primitive file to match the kinematics of your robot or your

File truncated at 100 lines see the full file

Changelog for package sbpl_lattice_planner

0.2.2 (2019-10-15)

• Add READMEs
• Contributors: Martin Günther

0.2.1 (2019-01-16)

• Reinit on map size, footprint and costmap changes
• Add warning when cost_scaling_factor is too large Also see #33.
• Ignore SBPL compile warning (#31)
• Fix example config for TF2 (#30)
• Update to tf2, add dependency
• Contributors: Jonathan Meyer, Martin Günther

0.2.0 (2018-09-03)

• Initial release into indigo, kinetic, lunar and melodic
• Contributors: Martin Günther, David V. Lu!!, Dave Hershberger, E. Gil Jones, Eitan Marder-Eppstein, Felix Widmaier, Johannes Meyer, Jon Binney, Vincent Rabaud, Austin Hendrix