Before I say anything please read this : I don't know whether it would be possible to create, but my one and only question is : Do rotary engines have something like this ?

Today I got an idea, I was thinking about variable pressure of apex seals against the wall of the engine (originally I was thinking about pneumatic or hydraulic system) but that would be too complicated, but then I thought about using spring which would push the apex seal out, but with higher RPM the spring would compress and push less and less, because the apex seal is pushed against the engine wall by centrifugal force. Do rotary engines have something like this or they use just the centrifugal force to push apex seals out ?

It should work like this : In low RPM there is small centrifugal force, therefore you need to use some kind of spring, but in high RPM there is enough centrifugal force, but if we sum up the force of spring and the centrifugal force, it's way too much and the engine wears up very quickly. But if we used something that would push (using centrifugal force) against that spring - in low RPM the spring would "help" the apex seals to seal the engine, and in high RPM it would compress and wouldn't create too much force against the wall, therefore by proper adjusting you would be able to keep constant force of apex seal against the wall of the engine in both low and high RPM.

 

Seals are retained against the trochoid housing mainly by gas pressure. The springs are only really there so the engine can start. This is a good chunk of why having excessive slot clearance leads to seal bounce and chatter.

Centrifugal force isn't as much a problem at high RPM as rubbing speeds are. A much simpler way to reduce centrifugal force effects would be to put a negative angle on the seal.