基于仿真的多部件系统状态维修决策优化方法

为通过部件组合维修提高维修效益,对采用状态维修的多部件系统,建立了部件状态随机劣化模型。采用幂指数函数建立以状态值为变量的可靠度函数,在考虑不完全维修、维修时间随机分布等因素的条件下,采用蒙特卡洛仿真方法建立了系统状态劣化过程模型。以单位寿命费用最小为优化目标,建立了多部件系统状态维修阈值的优化决策模型。案例分析结果表明,建立的状态维修决策优化模型能够显著降低维修费用、提高系统可用度,是适用且有效的。     

基于Gamma 过程的视情维修策略分析

针对现有文献对视情维修的研究忽略了设备检测时间的问题,建立一种基于Gamma过程的视情维修的解析模型。以维修费用为目标函数求解获得了设备的最优预防维修阈值和最优检测间隔,对设备的劣化状态进行描述并对维修过程建模,在该解析模型下,通过大量的数值仿真,分别比较分析了设备劣化状态变化特性以及维修能力对视情维修最优策略值选取的影响,并获得了相应的结论。仿真算例证明了该方法的可行性,可为维修方选取最优策略值提供一定的参考。     

基于比例风险模型的自行火炮齿轮箱状态维修决策

针对目前自行火炮齿轮箱所采取的传统维修方式一事后维修以及定期维修带来的缺陷，利用Weibull比例风险模型的建模思想，建立自行火炮齿轮箱基于状态信息的故障率模型；进而构建经济性要求下的维修决策模型，为同类型齿轮箱的最优化维修决策提供了一个可借鉴的量化方法。最后通过对某型自行火炮齿轮箱的案例应用，表明该方法在齿轮箱状态维修决策中的实用价值。     

基于关键零部件技术状态的机械产品定时维修间隔期优化方法

针对描述产品故障规律的函数很难获得和基于产品故障规律进行定时维修间隔期优化的方法在实际应用中有一定困难的问题,研究了基于产品关键零部件技术状态的定时维修间隔期优化方法。分析了基于关键零部件技术状态信息优化定时维修间隔期的思路,介绍了基于关键零部件技术状态信息评估定时维修方案合理性的方法,分别建立了维修不足和维修过剩时定时维修间隔期的优化模型。     

基于故障风险评估的状态维修决策模型

针对机械产品退化过程的特点，运用威布尔比例风险模型，建立了产品故障率与其工作时间及所处退化状态的关系，提出了基于故障风险的状态维修决策模型，实现了依据产品当前的工作时间及状态确定下步维修间隔或进行等故障风险维修决策的可能，并利用算例进行了分析．结果表明，该模型可以应用于具有安全性或任务性故障后果的机械产品的维修决策．     

一种基于状态监控的自动测试系统更换订购策略

针对海军导弹通用自动化测试系统的劣化故障,结合测试系统模块和元器件不可修复件多的特点,以及现有维修策略维修周期长的问题,提出一种基于状态监控维修更换和备件订购策略.该维修策略引入性能可靠性,通过状态监控和周期检查来确定不可维修模块劣化水平,进而基于模块劣化水平进行模块更换决策,并根据库存中剩余备件个数决定是否需要订购备件,减少停机时间,实现决策优化.理论分析和实例分析结果表明,与原策略相比,该策略能够缩短维修周期,提高使用可用度,保证系统的持续安全运行.     

舰船发电系统多状态可靠性马尔可夫报酬模型

针对舰船发电系统的多状态特征，考虑舰船计划维修间隔期对系统可靠性参数的影响，利用马尔可夫报酬模型构建冷储备结构的发电系统状态转移矩阵、报酬矩阵、报酬函数和系统需求满足函数，通过对报酬矩阵元素的合理赋值，获得系统区间可用度、平均可工作时间、平均停机时间、平均故障次数、计划维修间隔期内系统可靠度等参数，并通过算例验证模型正确性和适用性，分析系统计划维修间隔时间、单机组平均修复时间等指标对系统可靠性参数的影响，为研究舰船发电系统可靠性设计提供建模工具，为合理安排舰船装备维修结构提供技术支持。研究结果验证了马尔可夫报酬模型在复杂多状态系统可靠性建模和计算方面的便捷性和灵活性。     

多级保障设备寿命期内的可用度模型

针对具有三级维修机构保障的复杂设备,在小修修复如旧、中修大修均可使设备年轻固定时间的假设下,通过对设备使用和修理流程分析,给出了设备寿命期内的使用与修理状态转移图,建立了设备寿命期内的维修间隔期与可用度关系模型,求出了设备在固定的维修间隔期和一定维修转换规则下的平均可用度。案例分析得到了使可用度达到最大时的设备最佳维修间隔期,并通过与大修修复如新进行比较,说明了模型的适用性与灵敏性,可为设备维修决策提供依据。     

基于状态评估的相控阵雷达T/R组件维修策略研究

针对大型相控阵雷达T/R组件数量庞大、故障频发,且故障类型与多种检测参数有关的特点,提出了一种基于状态评估的T/R组件维修策略。根据T/R组件各测试数据之间的关联规则,构建了T/R组件的综合状态量和单项状态量集;针对常权重系数不能准确反映T/R组件真实工作状态的问题,引入均衡函数,并计算出了各综合状态量的变权重系数,建立了一种较为准确、客观的大型相控阵雷达T/R组件状态评估方法;根据相控阵雷达的参数指标确定了T/R组件的维修阈值,最终对机内自检检测的故障T/R组件进行状态评估,并对评分低于60分的T/R组件进行换件维修。实例计算结果表明,该评估方法和维修策略具有较高的可行性,能够充分发挥T/R组件的剩余寿命价值,对提高装备的保障效能具有重要意义。     

不完全维修条件下复杂系统的选择性维修决策方法研究

以复杂串联和并联系统任务为研究对象,建立了序贯任务条件下系统状态随机劣化过程模型。以最小维修、不完全维修和换件维修作为部件维修策略,在有限维修时间约束下,以当期系统任务可靠度最大化为目标,建立选择性维修决策模型以及相应的决策优化求解算法。案例分析表明：同时考虑役龄回退和风险修正的不完全维修模型能够更准确地描述系统可靠度;不完全维修策略可以在有限维修时间约束下,为复杂系统的选择性维修决策提供更大解空间,有助于相对提高系统可靠度。     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

Parameter Identification for the Valve Control Cylinder System of a Hydraulic Manipulator

In mechanical, hydraulic and electronic systems, the determination of system parameters is often challenging because liquid parameters often change significantly, due to variations in working and environmental conditions. Therefore, it is of significant practical importance to identify those parameters through experimental procedures. A systematic approach to identifying parameters in the valve controlling cylinder system of hydraulic manipulators is provided. It first derives the transfer function of the system, and then uses P control of PID control to predict system parameters. The predicted parameters are further validated using PID control. The prediction through simulation using MatLab language is utilized, which agrees well with experimental results.     

Three-dimensional Numerical Simulation of Combustion Field in the Combustion Chamber

In order to study the effect of rotation on the combustion in the underwater vehicle, a two-phase turbulent combustion process is described with Reynolds stress turbulence model, eddy-dissipation turbulent combustion model, P-1 radiation model and particle tracking model of liquid. The flow in the rotating combustion chamber is simulated at two different working speeds, 0 r/min and 1 000 r/min by Fluent software. The temperature, gas velocity, static pressure of wall and fuel concentration are computed and compared. The results show that the combustion in rotating combustor is faster and more effective.     

Software Communication Architecture Implementation and Its Waveform Application

This paper attempts to do a research on the development of software defined radio（SDR） based on software communication architecture（SCA）. Firstly, SCA is studied and a whole reference model of SCA3.0 core framework （CF） is realized; Secondly, an application-specific FM3TR waveform is implemented on the platform of common software based on the reference model; Thirdly, from the point of view of real-time performance and software reuse, tests and validations are made on the above realized CF reference model and FM3TR waveform. As a result, the SCA-compliant SDR has favorable interoperability and software portability and can satisfy the real-time performance requirements which are not too rigorous.     

Dynamic Simulation of the Tank Gun Recoil Response

By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle‘s velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.     

Survey of Controllable Suspension System for Off-road Vehicles

The controllable suspension system can improve the performances of off-road vehicles both on road and cross-country. So far, four controllable suspensions, that is, body height control, active, semi-active and slow-active suspensions, have been developed. For off-road vehicles, the slow-active suspension and the semi-active suspension which have controllable stiffness, damping and body height are more appropriate to use. For many years, some control methodologies for controllable suspension systems have been developed along with the development of modern control theory, and two or more original control methods are integrated as a new control method. Today, for military or civilian off-road vehicles, the R&D of controllable suspension systems is ongoing.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.