How to periodically execute a rule?

Hi,
Thanks for a great module!

I'm hoping to use Rules to periodically (e.g. every day at midnight or 6pm or whatever time) evaluate a condition (most likely expressed through my own custom PHP code) and when true, have the configured action(s) executed.
Is there a way to do this using Rules + Rules Scheduler?

I guess a possible implementation of this would be via some special action that re-schedules the triggered rule that is part of, for a later time, e.g. 24 hours into the future?
But I'm not sure if I can do this with Rules or how...
Another difference compared to a normal triggered rule would be, I think, that in this case there isn't a normal event as such triggering the process, other than "it is now time (e.g. 6pm)" to evaluate the condition.

Thanks for your time!