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According to the oscillating flow in servo-controlled hydraulic piplines, the actual movement of the transient transition flow was considered. The momentum change of the fluid was analysised in the transient process based on considering its micro-compression, and an improved fluid dynamic model of pipeline was proposed. Based on the one-dimensional fluid transient theory, the analytical model of fluid transients in hydraulic piplines was carried out by the characteristic method and the finite difference method. The correctness of the simulation was approved by the comparison of calculation data with experiment data. The results show that these models give more reasonable descriptions for water hammer and flow oscillation during servo valve starting process and can provide guidance for designs and experiments of the hydraulic pipe system. [ABSTRACT FROM AUTHOR]

Aiming at load simulating problem of the thrust vector control (TVC) system in launch vehicles, a new load simulator structure and its mathematical model are presented. The influence of main parameters on system's dynamic performance is analyzed by simulation. Building a prototype experiment system, multiple DOF load property is showed in a sweep frequency test. Simulation and experiment verify the feasibility of this load simulator structure, which lay a foundation for optimizing design parameters of the thrust vector servo mechanism and developing load simulators of heavy launch vehicles' servo systems. [ABSTRACT FROM AUTHOR]