Dynamic flow characteristics of digital hydraulic circuit based on high speed solenoid valve

High-speed solenoid valves are the key control element of digital hydraulic circuits, and their dynamic properties directly affect the circuit's flow performance. To improve the computational accuracy of the flow characteristics in digital hydraulic circuits, a flow calculation model incorporating a controllable duty cycle correction module is proposed in this article. The accuracy of the proposed model was validated using measured flow data within the linear duty cycle region. Experimental results demonstrate that, compared to the ideal switch model without delay, the dynamic flow characteristics model with actual switching delay enables the maximum and average relative error of the instantaneous flow to decrease by 20.3%, 9.3% and the maximum average error of the steady-state flow decreased by 73%, significantly improving computational accuracy. The average output flow rate of the hydraulic circuit at the operating frequency of f = 100 Hz typically increases by 40% of the rated flow in comparison to that at f = 50 Hz when the effective opening time t_se is between 2 ms and 7.43 ms. It is confirmed that fluid inertance has a significant impact on the delivery flow of digital hydraulic circuits.