Study on the braking process of the hydraulic actuator with discrete control

The study is aimed at improving the application effectiveness of the hydraulic actuator with discrete control, which is widely used in various fields. The goal is to improve the actuator performance by increasing its working speed while satisfying the braking characteristics. The study is based on a developed mathematical model of the hydraulic actuator, which includes the models of the discrete spool valve and the asymmetric hydraulic cylinder, and takes into account bi-directional movement of the rod, compressibility of the working fluid and nonlinear friction. Accuracy of the mathematical model is verified by comparing the simulation and experimental data. The study makes it possible to determine, for the specified parameters of the hydraulic actuator and the variation ranges of the working speed and inertial load, the quantitative relationship between working speed, braking time and maximum pressure. The study also reveals a new phenomenon of nonlinear influence of the spool response time on the braking time, which can be used to minimize the braking time. The obtained results can be used in the design of an actuator with discrete control, parameter setting of throttle elements, and development of control programs.