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Frequently Asked Questions

Question: What is the cause of the following behavior:

Short Answer: The problem is that the parameter min_obstacle_dist is chosen too high.

Long Answer: Just an exmaple: if the parameter min_obstacle_dist is set to a distance of 1m, the robot tries to keep a distance of at least 1m to each side of the door. But if the width of the door is just 1m, the optimizer will still plan through the center of the door (local minimum: both forces resulting from obstacle avoidance are negating each other in the center). But in order to satisfy the minimum distance to each pose the optimizer moves the planned poses along the trajectory (therefore the gap!). This case is not detected by the planner currently. However if there would be any collision, the feasiblity check would probably detect that. If you really have to keep large distances to obstacles you cannot drive through that door. Then you must also configure your global planner (robot footprint, inflation etc.) properly to avoid global planning through it. Otherwise reduce the minimum distance until the trajectory does not contain any large gap.

If you are using a robot footprint model other than the point model also check that the expansion ist correct and not too large (the footprint is published via markers).