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How do I make the local planner rotate in place?

asked 2015-08-12 14:40:06 -0500

updated 2018-05-05 11:49:39 -0500

How can I get the local planner to turn in place and then head towards a goal instead of moving forward and turning at the same time? I am facing issues when the robot is able to reach a goal but cannot come back to the same point by doing a turn in place and following a similar global plan. The local planner tries to make the robot move forward and turn. But it then comes too close to an obstacle and get stuck.

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Does anyone have a suggestion about this please? It would be really helpful.

DanThe gravatar image DanThe  ( 2016-03-17 16:14:27 -0500 )edit

If you have a comment please post it as a comment; not an answer.

ahendrix gravatar image ahendrix  ( 2016-03-17 16:26:23 -0500 )edit

2 Answers

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answered 2016-03-17 16:28:17 -0500

ahendrix gravatar image

If your robot gets too close to obstacles, you should figure out why it's doing that; not try to force complicated heuristics on the planner.

You may want to adjust your footprint or the obstacle distance bias in the local planner.

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Thanks for your answer. The problem is not that it is getting too close to obstacles but when working in confined spaces, I would like to prevent the robot from doing large translations when trying to rotate to avoid collisions. Which is the obstacle distance bias parameter for trajectory rollout?

DanThe gravatar image DanThe  ( 2016-03-17 16:37:46 -0500 )edit

Just in case it is helpful to anyone, in the parameters for TrajectoryPlannerROS - setting the occdist_scale parameter to a value higher than the default value, helps to control the turning radius of the robot.

DanThe gravatar image DanThe  ( 2016-03-19 08:40:35 -0500 )edit

Indeed. I set occdist to 0.1 (from default 0.05) and the robot preferred to rotate in place longer before moving.

felipeduque gravatar image felipeduque  ( 2020-05-04 09:29:52 -0500 )edit

answered 2016-04-07 19:47:38 -0500

pgigioli gravatar image

updated 2016-04-07 19:48:54 -0500

Have you tried allowing the planner to move the robot backwards? I was having a similar problem except even with an in place rotation the robot would get stuck when too close to obstacles. Simply change the min_vel_x param for the dwa_local_planner to a negative value to allow backwards planning.

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Asked: 2015-08-12 14:40:06 -0500

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Last updated: May 05 '18