Boost Control: How to Optimize Turbo Pressure

I have a question about the boost pressure control system. Does it work based on characteristic curves, meaning does the engine control unit (ECU) 'know' about the performance of the turbocharger and then set a boost pressure based on a characteristic curve (e.g., by controlling a valve for a specific time to position the variable turbine geometry (VTG) in a certain way)? Or is the boost pressure actually measured, and then regulated to the target value?

Hi,

As far as I know, it's a mixture of both.
At higher engine speeds, the variable turbine geometry (VTG) is already adjusted to a position that is intended to prevent excessively high turbocharger speeds in the event of sudden full acceleration, because the control system is relatively slow to respond.
Starting from this point, the desired boost pressure is regulated by comparing the target value with the actual value.