We proposed a novel 2D electric feedback flow control valve to solve the problem of low integration and control accuracy of flow control valves. The torque motor of the valve drives the 2D piston to rotate, and the rotational motion is converted to axial motion and drives the spool. The differential pressure feedback rod on the valve body can accurately measure the differential pressure of the oil inlet and outlet and cooperate with the spool displacement to form a closed loop of flow. This loop of flow then overcomes the influence of the valve port’s load change on the flow. We first established the mathematical model of the valve, obtained the transfer function, and performed the stability analysis. Then, we used AMESim as a platform for simulation analysis. Finally, we conducted the experimental verification of the valve. The verification showed the following characteristics of the valve. The hysteresis loop is 4.4%. The linearity is 1.6%. The response time is about 44 ms. The amplitude bandwidth is about 17 Hz. The phase bandwidth is about 28 Hz. The valve’s steady-state flow error is less than 8%, suggesting its broad application prospect in the aerospace and military fields.

Aiming to solve the difficult problem of the miniaturization of servo valves, this paper designs a subminiature two-dimensional (2D) electro-hydraulic servo valve, which realizes the integration of the pilot stage and the power stage and significantly improves the work-to-weight ratio. Meanwhile, a high-power-density brushless DC motor (BLDC) is adopted as the electro-mechanical converter to further reduce the volume and mass. Firstly, the structure and working principle of the two-dimensional (2D) servo valve are described, and the mathematical model of the electro-mechanical converter is established. Aiming at the special working condition of the electro-mechanical converter with high-frequency oscillation at a small turning angle, this paper designs a position–current double closed-loop PID control algorithm based on the framework of the vector control algorithm (FOC). At the same time, the current feedforward compensation technique is included to cope with the high-frequency nonlinear disturbance problem of the electro-mechanical converter. The stability conditions of the electro-mechanical converter and the main valve were established based on the Routh–Hurwitz criterion, and the effects of the control algorithm of the electro-mechanical converter and the main parameters of the main valve on the stability of the system were analyzed. The dynamic and static characteristics of the 2D valve were simulated and analyzed by establishing a joint simulation model in Matlab/Simulink and AMESim. The prototype was fabricated, and the experimental bench was built; the size of the experimental prototype was 31.7 mm × 29.3 mm × 31 mm, and its mass was 73 g. Under a system pressure of 7 MPa, the flow rate of this valve was 5 L/min; the hysteresis loop of the spool-displacement input–output curve was 4.8%, and the linearity was 2.54%, which indicated that it had the ability of high-precision control and that it was suitable for the precision fluid system. The step response time was 7.5 ms, with no overshoot; the frequency response amplitude bandwidth was about 90 Hz (−3 dB); the phase bandwidth was about 95 Hz (−90°); and the dynamic characterization experiment showed that it had a fast response characteristic, which can satisfy the demand of high-frequency and high-dynamic working conditions.