Understanding Cost Increment in Path Planning with Validator

[zzz11wh]

Hello, open-rmf community,

I'm currently delving into robot path planning and have noticed an intriguing behavior during the process, which involves conducting two distinct searches: one without a validator and another with a validator. During the second search, where the validator is present, I observed that the cost for each waypoint in the queue is incremented by 1, regardless of whether a conflict is detected.

As a beginner in this field, I might be missing some fundamental understanding of why this is the case. Could someone kindly explain the rationale behind this cost incrementation during the search with a validator? Is this a standard practice in path planning to account for certain factors, or could there be another explanation?

I appreciate any insights you can provide. Please excuse me if my question seems naive; I'm eager to learn and understand more about this fascinating topic.

Thank you very much!