pump flow control

First of all, you need to tell what type of Pump you are working on to control the flow, e.g. centrifugal, diaphragm or reciprocating Pump, you need to maintain system pressure or can live with lower pressure while flow rate is reduced.

A detailed descriptions of pumping system will narrow down available solutions.
I'm working on flow rate control of variable displacement piston pump using combined neural network and genetics algorithms.
I want to know if someone here worked on controlling the flow rate of a variable displacement pump. I'm in need of data for simulations.