Abstract: Nowadays, in order to make the outlet flow stable, flow control valves usually adopts mechanical pressure difference compensator or dynamic flow meter to compensate the variations of pressure difference. Its disadvantages are low control precision, complex mechanical structure, small flow capacity and so on. To tackle some of the problems, a two-stage proportional flow control valve based on bilinear interpolation control strategy is presented. The proposed valve is composed of a Valvistor poppet (main stage), a proportional directional valve (pilot stage), a flow compensation controller and two pressure sensors. The pressure drop across the poppet metering orifice are measured by two pressure sensors and fed back into the flow compensation controller. With the help of the bilinear interpolation algorithm, a compensation voltage is calculated from the given flow rate and the measured pressure drop. Then, the compensation voltage is delivered into the pilot stage to regulate the pilot spool. In order to verify the feasibility of the proposed valve, a simulation model is established by means of SimulationX, and a test research is also carried out. Its dynamic and static characteristics are analyzed. Results show that the proposed valve has a good static control performance, and the output flow keeps approximately constant under variable load conditions; in addition, the greater pressure drop across the poppet metering orifice is, the faster the dynamic response of the poppet becomes. Under step response of the load pressure conditions, it indicates that the ability to resist load interference is reduced with the increase of pressure difference.

Key words: bilinear interpolation, digital compensation, dynamic and static characteristics, proportional flow valve, Valvistor valve