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question about avoiding obstacle

asked 2017-02-10 15:46:05 -0500

ghaith gravatar image

Hi , I am trying to use the navigation stack and every thing is good I have some question and small problem:

1- Now the inflation radius say that its the maximum distance allowed for the robot from obstacle in the cost map common parameter; my robot radius is about 15 cm but I but it about 23 and inflation radius about 40 cm but still some time enter the inflation zone and some time hit the obstacle I don't know if its problem caused by the parameter above or not.

2- I need to know what cost factor exactly do I didn't understand it good so I hope any one can help.

3- base local planner I didn't use meter_scoring is this will cuse any harm.

I hope some one can make every thing clear to me. Thanks in advance .

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please, clarify this statement: "my robot radius is about 15 cm but I but it about 23 and inflation radius about 40 cm"

Procópio gravatar imageProcópio ( 2017-02-28 03:28:45 -0500 )edit

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answered 2017-02-28 03:38:12 -0500

Procópio gravatar image

updated 2017-02-28 03:43:10 -0500

this image is very informative and helps understand what is going on in your costmaps: image description

1 - It is unlikely that your collisions are caused by the robot radius parameter, as I understand you set bot the circumscribed radius to be larger than reality and the same goes for the inflation radius.

2 - Firstly, in normal situations the robot should never plan or enter the zones below the circumscribed radius. Then you can set the inflation radius which, as shown in the figure below, is a buffer zone. One way to understand this buffer zone is: the robot can enter this zone if necessary, but it would rather avoid it. As not getting too close to walls unless in a narrow passage, for example. The cost_scaling_factor will determine how the costs are distributed in the buffer zone. As an example, they can fall abruptly or slowly after the circumscribed radius, reflecting your preference on how close from an object you are willing to go if necessary.

3 - I propose you create another question about this. This is related to your local_planner, and the interaction among its parameters, which is another subject.

extra references: costmap inflation robot-clearance-from-walls

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Asked: 2017-02-10 15:46:05 -0500

Seen: 336 times

Last updated: Feb 28 '17