Research and application of speed stability of flow stabilizing valve in direct-drive electro-hydraulic servo system

When the direct-drive electro-hydraulic servo system is used for position control of hydraulic actuators, load unbalance or external disturbances can cause flow imbalance, leading to poor speed stability of the actuator and thus reduced position accuracy. To address this issue, a flow stabilizing valve with a special structure is proposed, which suppresses flow fluctuations through a mechanical passive compensation mechanism. This paper elaborates on the structural innovations, working principle, and operation circuit of the flow stabilizing valve, and compares it with traditional flow control valves to highlight its advantages in low complexity and high reliability. Simulation models with and without the flow stabilizing valve are built in AMESim to analyze speed and displacement characteristics under different load disturbances. The results verify that the valve significantly improves speed stability but introduces a response lag of approximately 3 s. A test platform is constructed to test low-frequency (0.1–0.5 Hz) and low-amplitude (≤30 mm)signals, clarifying the system's applicable scenarios. The results show that the flow stabilizing valve can control the speed deviation caused by load disturbances within 0.0016 m/s by quickly adjusting the flow rate of the hydraulic cylinder, effectively improving position accuracy.