Fluid control apparatus and flow rate ratio control apparatus

A flow rate ratio control apparatus that controls a flow rate ratio of fluid flowing through multiple branch flow paths branching from an end of a supply flow path through which the fluid is supplied, the flow rate ratio control apparatus comprising:

• multiple fluid control apparatuses that are respectively provided in the respective branch flow paths and each of which is provided with a valve, a flow rate sensor, and a valve control part adapted to control an opening of the valve so that a deviation between an inputted reference flow rate and a measured flow rate by the flow rate sensor decreases;
• a pressure sensor provided in the supply flow path or on an upstream side of the valves of the respective fluid control apparatuses in the respective branch flow paths;
• a total flow rate acquisition part that respectively acquires the measured flow rates by the respective flow rate sensors provided in the respective branch flow paths, and acquires a total flow rate that is a sum of the respective measured flow rates;
• a reference pressure determination part that is inputted with the total flow rate, and on a basis of a flow rate-pressure map, determines a reference pressure corresponding to the total flow rate,
• a target total flow rate calculation part that calculates a target total flow rate so that a deviation between the reference pressure determined by the reference pressure determination part and a measured pressure measured by the pressure sensor decreases;
• and
• a flow rate distributor that, on a basis of the target total flow rate and a predetermined target flow rate ratio of the fluid flowed through the respective branch flow paths, determines reference flow rates to be inputted to the fluid control apparatuses provided in the respective branch flow paths.