多级气动液压弹射装置建模及性能研究

分析气动液压弹射方式的两种弹射装置类型，研究一种以压缩空气为动力源、油液为传动介质，且具备油液自缓冲结构的多级气动液压弹射装置的弹射性能。针对弹射过程中气腔气体复杂多变过程、封闭油腔油液流动非线性、多级缸运动关系的不确定性及油液缓冲结构，结合真实气体热力学效应，推导封闭油腔油液的压力动态变化模型及多级缸动力学非线性模型，建立描述多级气动液压弹射过程的数学模型；通过数值求解方法，分析该多级气动液压弹射缸的运动规律及弹射性能。研究结果表明：该多级气动液压弹射缸建压过程迅速，并能在0.2 s内以2.4 m有效弹射行程，将重1.5 t负载加速至19 m/s，弹射最大过载不超过16 g，且相邻两级缸的相对速度不超过15 m/s. 分析气动液压弹射方式的两种弹射装置类型，研究一种以压缩空气为动力源、油液为传动介质，且具备油液自缓冲结构的多级气动液压弹射装置的弹射性能。针对弹射过程中气腔气体复杂多变过程、封闭油腔油液流动非线性、多级缸运动关系的不确定性及油液缓冲结构，结合真实气体热力学效应，推导封闭油腔油液的压力动态变化模型及多级缸动力学非线性模型，建立描述多级气动液压弹射过程的数学模型；通过数值求解方法，分析该多级气动液压弹射缸的运动规律及弹射性能。研究结果表明：该多级气动液压弹射缸建压过程迅速，并能在0.2 s内以2.4 m有效弹射行程，将重1.5 t负载加速至19 m/s，弹射最大过载不超过16 g，且相邻两级缸的相对速度不超过15 m/s.

Theoretical Modeling and Performance Research on Multi-stage Pneumatic and Hydraulic Catapult Device

A novel multi-stage pneumatic and hydraulic catapult device with oil buffering structure，which utilizes compressed air as impetus and hydraulic fluid as transmission medium, is introduced and its ejection performance is researched by analyzing two typical catapult devices involving pneumatic and hydraulic catapult. According to the complex polytropic process of gas, the flow nonlinearity of hydraulic fluid in enclosed chamber, motion uncertainty of multi-stage cylinders and the self-buffering structure, a mathematical model describing multi-stage pneumatic and hydraulic catapult process is established based on real gas thermodynamic effect. Meanwhile, the dynamic variation model of oil pressure in enclosed chamber and the nonlinear dynamic model of multi-stage cylinders are constructed. The motion laws and working performance of multi-stage pneumatic and hydraulic catapult cylinder are obtained through numerical simulation. The results show that the proposed multi-stage pneumatic and hydraulic catapult device can generate the appropriate pressure quickly and accelerate the load up to 19 m/s within 0.2 s with the speed-up distance of 2.4 m, and thus the overload is less than 16 g and the relative velocity between two adjacent cylinders is less than 15 m/s.