液压弹射机构设计及其关键控制元件的研究

发布时间：2018-01-11 04:25

本文关键词：液压弹射机构设计及其关键控制元件的研究　出处：《浙江工业大学》2013年博士论文　论文类型：学位论文

【摘要】：弹射机构利用系统预先储存能量的快速释放实现对弹射对象的瞬间加速,广泛应用于现代军事及普通工业,如航母飞机的弹射起飞、导弹的弹射发射、弹射救生座椅、汽车碰撞试验等。根据动力元件的不同,弹射机构主要分为机械式、燃气式、压缩空气式、蒸汽式、电磁式以及液压式,其中,液压弹射机构具有功率重量比大、响应速度快、控制精度高、易于实现缓冲、噪声小等优点,在高性能的应用场合逐渐受到重视。液压弹射机构以液压缸活塞的高速运动为主要特征,关键技术难点包括大功率瞬时能源的供应、高速液压执行元件的密封与缓冲、高速大流量的弹射控制阀及其导控级高频伺服阀的研制开发,可见,液压弹射机构属于高速大功率液压系统,随着液压设备正朝着高速、大功率、低噪声方向发展,对上述关键技术的研究成果,具有广泛的应用前景。本文首先对液压弹射机构的发展现状和相关应用领域进行了总结和分析,论述了高速液压缸和高频响、大流量伺服阀的研究现状,在此基础上,对液压弹射机构及其关键控制元件-高频、大流量2D伺服阀开展研究,主要研究内容及成果如下： 1.针对特定的应用场合,主要提出以下几种液压弹射机构原理方案,一是低速液压弹射机构,其液压缸活塞最大速度达到8m/s,活塞加速时间约70ms,并对其进行改进设计；二是高速液压弹射机构,设计指标为活塞初始20mm行程时速度达到2m/s以上,最大速度达到15m/s；三是双液压缸同步弹射机构,两个液压缸同步弹出,最大速度6m/s；还有超高速液压弹射机构,对应活塞速度达到20m/s以上。以高速液压弹射机构为例,讨论了弹射机构的参数计算及结构设计。 2.为解决高速大流量开关阀的流量和响应速度之间的矛盾,提出了双节流口并联输出的结构方案,对开关阀的零位泄漏特性、阀口流动特性以及压力特性进行理论分析和实验研究,其在2MPa进出口压差下的流量达到3000L/mmin,建立了开关阀阀芯运动过程的数学模型,分析了结构参数对其动态特性的影响,并搭建样机进行了实验验证,在10MPa工作压力下,开关阀的开启时间低于15ms,探讨了筛阀的结构方案。 3.为提高频响和流量,将圆孔型导控结构的2D伺服阀改成满弓型结构,通过对2D伺服阀的静态特性分析,其导控级零位泄漏在21MPa时约为0.5L/min,建立了2D伺服阀伺服螺旋机构的数学模型,通过线性和非线性仿真分析了工作压力、初始弓高、面积梯度等对频率特性和阶跃响应特性的影响,理论分析表明圆孔型导控结构在-3dB幅值衰减下的频响约250Hz,而满弓型则达到800Hz,实测满弓型阶跃响应时间约1.6ms,圆孔型约3ms,证明了满弓型结构较圆孔型的动态特性有显著提高,为研制高频、大流量2D伺服阀奠定基础。 4.为解决液压缸活塞的高速缓冲,提出活塞式液压缸缓冲结构,理论分析表明活塞初始间隙对缓冲腔峰值压力影响最为显著,建立了活塞式缓冲结构的动力学模型,通过仿真和实验研究了活塞式缓冲过程的动态特性,其能够在60mm缓冲行程内将活塞速度由7m/s降至0.6m/s以下,分析了结构参数对缓冲性能的影响,在此基础上,进一步提出了两级缓冲和组合缓冲,并探讨了超高速液压缸的结构方案。 5.建立了由蓄能器—开关阀—液压缸组合的高速液压弹射机构的工作过程的数学模型,利用MATLAB软件仿真分析了结构参数和工作参数对弹射机构动态特性的影响,并搭建了样机进行实验,表明弹射机构在8MPa工作压力下,l00ms时间内,将150kg负载加速至8m/s且活塞初始20mm位移时的速度达到2.0m/s以上。 6.对双缸闭环液压弹射机构及其关键技术进行了分析,利用闭环液压弹射机构的数学模型研究了双缸同步开环控制特性,并通过建立近似的线性化传递函数,研究了双缸同步闭环控制特性,理论上,闭环阶跃响应时间约为50ms。
[Abstract]:Quick release ejection mechanism using system stored energy to achieve the object of the instantaneous acceleration of ejection, widely used in modern military and ordinary industries, such as aircraft catapult take-off, missile ejection, ejection seat, car crash test. According to the dynamic elements, ejection mechanism is mainly divided into mechanical type, gas type, compressed air, steam, electromagnetic and hydraulic, hydraulic ejection mechanism which has the power to weight ratio, fast response speed, high control accuracy, easy realization of buffer, lower noise, has attracted much attention in the application of high performance hydraulic ejection mechanism is moving at a high speed. As the main hydraulic cylinder piston the characteristics, key technical problems including high power transient energy supply, high speed hydraulic sealing and cushioning element, the ejection control valve and pilot stage high frequency servo valve with high speed and large flow Research and development shows that hydraulic ejection mechanism is a high-speed and high-power hydraulic system. With the development of high speed, high power and low noise, hydraulic devices will have extensive application prospects for the above key technologies.
Firstly, the development status of the hydraulic ejection mechanism and related applications are summarized and analyzed, discussed the high speed hydraulic cylinder and high frequency response, research status of large flow servo valve, on the basis of the hydraulic ejection mechanism and the key control elements - high frequency, large flow servo valve 2D to carry out the research, the main research contents and results the following:
1. for specific applications, mainly put forward the following several hydraulic ejection mechanism is a principle scheme of low speed hydraulic ejection mechanism, the hydraulic cylinder piston piston maximum speed of 8m/s, acceleration time is about 70ms, and carries on the improvement design; two is the high speed hydraulic ejection mechanism, design index for the piston stroke 20mm initial speed of 2m/s above, the maximum speed reached 15m/s; three is the synchronous ejection mechanism of double hydraulic cylinders, synchronous pop-up two hydraulic cylinders, a maximum speed of 6m/s; and ultra high speed hydraulic ejection mechanism, the corresponding piston speed is more than 20m/s. The high speed hydraulic ejection mechanism as an example, discusses the design and calculation of the structure parameters of ejection mechanism.
The 2. is to solve the contradiction between high speed and large flow valve flow and the response speed of the proposed scheme of double orifice valve in parallel output, zero leakage, valve flow characteristics and pressure characteristics of the theoretical analysis and experimental research, the 2MPa import and export under pressure flow reached 3000L/mmin, set up the mathematical model of valve spool movement process, analyzes the influence of structure parameters on the dynamic characteristics, and build an experimental prototype verification in 10MPa work under pressure, the valve opening time is lower than 15ms and the structure scheme of the sieve valve.
3. in order to improve the response and flow, 2D servo valve hole will guide control structure into Mangong type structure, the static characteristics of 2D servo valve is analyzed, the pilot stage zero leakage at 21MPa is about 0.5L/min, established the mathematical model of 2D servo valve servo screw mechanism, through the linear and nonlinear simulation analysis of the working pressure, initial bow high gradient area, step response of the frequency and order, the theoretical analysis shows that the frequency response of circular type pilot structure in -3dB amplitude attenuation under about 250Hz, while the full bow is up to 800Hz, the measured full bow step response time is about 1.6ms, round about 3MS, that significantly improve the dynamic characteristic of the full bow type structure with round groove, lay the foundation for the development of high frequency, high flow 2D servo valve.
4. for high speed buffer solution of the hydraulic cylinder piston, piston type hydraulic cylinder buffer structure is proposed, the theoretical analysis shows that the effect of initial clearance of piston buffer cavity peak pressure is the most significant, established a dynamic model of piston type buffer structure, dynamic characteristics of piston buffer are studied through simulation and experiment, it can travel in the 60mm buffer the piston speed from 7m/s to 0.6m/s, analyzed the influence of structure parameters on the performance of the buffer, on this basis, further puts forward the two level buffer and buffer, and discusses the ultra high speed hydraulic cylinder structure scheme.
5. to establish a mathematical model for the working process of high speed hydraulic ejection mechanism for valve - hydraulic cylinder by the combination of the storage, analysis the influence of structure parameters and operating parameters on the dynamic characteristics of the ejection mechanism by MATLAB software simulation, and built a prototype experiment shows that the ejection mechanism in 8MPa under the working pressure, l00ms time 150kg, 8m/s and the initial load acceleration to 20mm displacement speed when the piston reaches above 2.0m/s.
6. of double closed-loop hydraulic ejection mechanism and its key technologies are analyzed, on the double cylinder synchronous open loop control based on the characteristics of mathematical model of closed loop hydraulic ejection mechanism, and through the establishment of a linear transfer function approximation, the double cylinder synchronous closed-loop control characteristics, theory, closed-loop step response time is about 50ms.

【学位授予单位】：浙江工业大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH137

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