why the robot response to the obstacles so late?

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hi ,

I have noticed that my robot response to the obstacle so late, I mean when it reaches to the obstacle now it starts detouring, while I expect that at least from 1 m before, it has detected the object. the local costmap is also big enough that the object is also situated in this costmap, but the robot response so late. what should i do? I am working with warthog robot, if anybody have the parameters which work best for warthog, is really appreciated it.