Research on equivalent simplified modeling and simulation of digital hydraulic cylinder

To address the challenges in traditional modeling methods for highly integrated electro-mechanical-hydraulic digital hydraulic cylinders, such as complex nonlinear factors, high parameter uncertainty, and low simulation efficiency, this study proposes two equivalent simplified modeling and simulation methods based on the negative feedback mechanism. Firstly, a valve port control model based on equivalent feedback of displacement signals is established by constructing a closed-loop feedback mechanism between piston displacement and spool displacement. Secondly, a mathematical mapping between the valve opening and the relative displacement of the spool and sleeve is formed by utilizing the linkage following relationship between the valve sleeve and spool, resulting in a modeling method based on equivalent feedback of sleeve following. Two equivalent models of the digital hydraulic cylinder are developed using the AMESim platform, and the correctness and basic equivalence of the model were verified through simulation and performance testing. Based on the equivalent model, the influence of key parameters on the dynamic characteristics of the system can be analyzed. This approach provides a relatively simplified modeling method for the complex engineering application system analysis of digital hydraulic cylinders. The proposed negative feedback equivalent modeling approach may offer a referable approach for facilitating modeling and simulation implementation in other systems.