Testing DWA Local Planner - approaches goal, stops, keeps swinging left & right

asked 2013-10-26 00:23:58 -0600

1137 ●77 ●90 ●104

updated 2013-10-27 13:49:32 -0600

I'm trying the DWA Local Planner as an alternative for the TrajectoryPlanner. At first it moves heading to the given goal pretty fast. But close to the goal, that is about half a meter which still is quite a distance considering that the whole world of the robot is just a plane of 2 by 3 meters, it kind of stops and keeps like dancing in place.

Here's my parameter dump for the local costmap and the DWA Local Planner. There has to be something wrong...

//edit: Okay, I overlooked an error message coming out of the local planner. Here it is:

None of the 94 first of 94 (94) points of the global plan were in the local costmap and free

What might be causing this error?

Thanks for your help!

Cheers, Hendrik

answered 2013-11-01 05:30:55 -0600

David Lu

10932 ●123 ●219 ●250 http://MetroRobots.com/

I have also found some problems around the end of the plans. This is due to some errors in DWA with setting the weights of the different critics. I hope to have a fix for it soon.

For the updated error, do your global map and local map line up the way you think they should?

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Most of the time. However, sporadically I see wrong tf data (i.e. /base_link jumping to a wrong location for a fraction of a second and immediately return to the correct location). No filters are running yet, so this might likely have some negative influence on the quality of the navigation stack.

Hendrik Wiese ( 2013-11-01 05:38:31 -0600 )edit

AMCL Problem?

David Lu ( 2013-11-01 06:43:02 -0600 )edit

AMCL isn't started. My robot is just simulated and the simulator provides me with perfect sensor data (x, y, a, vx, vy, va). Despite that tf sometimes jumps around. I've still got to investigate that before ROS can take over controlling the real robot (which isn't even built, yet).

Hendrik Wiese ( 2013-11-01 08:29:06 -0600 )edit

So, how about the problems at the end of a plan? By when, approx., do you think you can fix them? Matter of hours? Days? Months? Just curious... on one hand. On the other hand, unfortunately, I've got a pretty strong deadline...

Hendrik Wiese ( 2013-11-02 23:44:40 -0600 )edit

Are you compiling your own version of DWA?

David Lu ( 2013-11-04 04:38:02 -0600 )edit

Nope. Not yet. Should I?

Hendrik Wiese ( 2013-11-04 08:54:50 -0600 )edit

Which version are you running?

David Lu ( 2013-11-04 09:34:49 -0600 )edit

My basic fix is to change this line: https://github.com/ros-planning/navigation/blob/hydro-devel/dwa_local_planner/src/dwa_planner.cpp#L270 to be sq_dist > forward_point_distance_ * forward_point_distance_ * 2

David Lu ( 2013-11-04 09:45:55 -0600 )edit

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