Ask Your Question
2

Path planning for car-like robots

asked 2011-11-01 10:12:20 -0600

Sagnik gravatar image

Hi,

I am developing a path-planner for a 4 wheeled car-like robot. I have a 2D map of the environment with the initial coordinates of the robot and the final coordinates known. A straight-forward solution would be to use A* or any general path planning algorithm like it, but the challenge I see is in ensuring that the curvature in the path is achievable by a 4 wheeled (non-holonomic) robot.

Also, as a second step, the robot uses a visual marker (hung on a wall in front of it) to localize itself. So the path planned should ensure that the robot's heading is such that the marker is always in view.

Does ROS have packages that I could use or take ideas out of ?

Thanks, Sagnik

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted
7

answered 2011-11-01 19:58:04 -0600

We use the sbpl lattice planner (http://www.ros.org/wiki/sbpl_lattice_planner) on our four wheel drive/steering Hector UGV. You can specify the allowed motion primitives as described in the documentation. The plan will then only consist of valid motion for you Ackermann-steered vehicle. The only problem then is to follow this trajectory exactly, which move_base doesn't do in my experience.

See also this answer: http://answers.ros.org/question/27/how-can-i-use-the-navigation-stack-on-a-carlike

edit flag offensive delete link more

Comments

Hi, I was able to install sbpl lattice planner as suggested and could run the move_base_sbpl_fake_localization_2.5cm.launch file (Section 2.2 of http://www.ros.org/wiki/sbpl_lattice_planner ). But how do I actually go ahead and set a goal and see a plan being generated ?
Sagnik gravatar imageSagnik ( 2011-11-28 07:59:24 -0600 )edit
I tried setting a goal using RViz but it doesn't seem to work. If you could point to some tutorial demonstrating the usage of sbpl_lattice_planner, that would be great. Thanks !
Sagnik gravatar imageSagnik ( 2011-11-28 08:00:44 -0600 )edit
You don't need a tutorial that is specific to the sbpl_lattice_planner. You should look at the documentation for the navigation stack (move_base etc.). The lattice planner is just one of many different global planners that could be used - and they are all interfaced with in the same way.
ben gravatar imageben ( 2011-11-28 11:46:10 -0600 )edit
Also - when setting the goal in rviz - make sure that the global frame of the world is '/map'.
ben gravatar imageben ( 2011-11-28 11:46:36 -0600 )edit

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer

Question Tools

2 followers

Stats

Asked: 2011-11-01 10:12:20 -0600

Seen: 3,204 times

Last updated: Nov 01 '11