Finite Element Modelling of Failure of a Multi-Material Target due to High Velocity Space Debris Impacts

Lagrangian finite element methods have been used extensively in the past to study the non-linear transient behaviour of materials, ranging from crash tests of cars to simulating bird strikes on planes. However, as this type of space discretisation does not allow for motion of the material through the mesh when modelling extremely large deformations, the mesh becomes highly distorted. This paper describes some limitations and applicability of this type of analysis for high velocity impacts. A method for dealing with this problem by the erosion of elements is proposed, where the main driver is the definition of element failure strains. Results were compared with empirical perforation results and were found to be in good agreement. The results were then used to simulate high velocity impacts upon a multi-layered aluminium target in order to predict a ballistic limit curve. LS-DYNA3D was used as the FE solver for all simulations. Meshes were generated using Truegrid.     

飞机发动机燃料计量系统故障分析的一种方法

随着产品成本和复杂性的提高，故障模式影响分析已成为复杂系统设计过程中不可或缺的部分。但其有效性多年来一直存在争议，其主要原因在于采用以经验为主的定性推理法，分析繁琐，工作量大，导致很难确定每种故障模式的故障影响。本文从BIT设计的角度，以功能角色模型理论为基础，导出在反馈系统中的推理规则和故障模式影响分析方法。最后以喷气式发动机燃料计量系统为例，阐述对该系统进行故障分析的一般步骤。研究表明，本文提出的功能角色模型理论可有效提高故障模式影响分析效率。     

对接综合试验台控制系统软件快速原型开发技术

对基于快速原型设计睁对接综合试验台控制系统软件开发进行了研究。介绍了根据系统方案进行的中央控制台软件设计和模型计算机软件开发等。给出了快速原型设计,以及包括接口设计、配置管理、文档管理等软件工程化管理等关键技术。     

机载校飞监控系统的设计与仿真

由于校飞用合作目标载体的变化,导致原有监控系统不能适应,必须设计一套校飞控制系统来保障设备操控要求。对系统的软、硬件进行详细设计,在Proteus中进行硬件仿真,通过构建虚拟环境,进行软件级联测试,表明该系统设计完全满足校飞任务需求。     

某型航空发动机落压比调节器性能及故障分析

根据某型航空发动机落压比调节器的控制原理,建立压力比敏感元件的数学模型,分析了落压比调节器的滞环误差、不敏感区、灵敏度等影响参数。分析结果表明：πr值偏离故障是由薄膜灵敏度太差和反馈弹簧力值偏小造成的。     

模糊PID控制在船载测控系统中的应用研究

针对目前船载测控雷达天线伺服系统中采用传统PID控制存在超调量大、响应时间长等不足,比较了传统PID控制和模糊控制的不同特点,讨论了模糊PID控制器的设计方法,并利用MATLAB软件对系统进行了辅助设计与仿真实验。仿真结果表明,该控制方法可以提高伺服系统的快速性和平稳性,有效增强船载测控系统的跟踪性能。     

多轮飞机滑水保护

飞机以一定的速度在积水跑道上滑行时,因滑水导致飞机操纵性变差,甚至刹车失灵等现象。分析了滑水产生的机理,从跑道、轮胎、使用技巧、并着重从刹车控制系统角度介绍多轮飞机滑水保护措施,通过地面动力联试表明,刹车系统自身的滑水保护措施对于提高飞机的安全性起着至关重要的作用。     

分供方测量的控制与管理

国际标准的推广实施，使企业计量工作的运作观念发生重大的变化，同时也给计量工作如何实效服务生产经营提出新的课题。本文结合质量体系认证、计量检测体系合格确认工作中的实践，分析、探讨了企业建立完善计量检测体系过程中，对分共方测量工作进行控制、管理的有关方法、难点。     

试验中被制导目标的定位及安控应用

从飞行器试验安全控制角度，讨论了在末制导系统捕获目标后，如何融合外测和遥测数据以获取目标的位置信息。要点是目标位置的计算方法及其应用于安控显示软件。给出一个实例；用实时测量数据解算出飞行器制导目标的位置，并在电子地图上显示。     

Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes

An adaptive sliding mode control(ASMC) law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot.Each joint of the system is a free ball joint capable of rotating with three degrees of freedom(DOF).A cluster of control moment gyroscopes(CMGs) is mounted on each link and the base to actuate the system.The modified Rodrigues parameters(MRPs) are employed to describe the angular displacements,and the equations of motion are derived using Kane's equations.The controller for each link or the base is designed separately in decentralized scheme.The unknown disturbances,inertia parameter uncertainties and nonlinear uncertainties are classified as a ‘‘lumped" matched uncertainty with unknown upper bound,and a continuous sliding mode control(SMC) law is proposed,in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty.A general amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input.Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov's method.Simulation results based on a three-link system verify the effectiveness of the proposed controller.