In-process drilled hole inspection for aerospace applications

The principles of operation and comprehensive testing of a prototype system for high speed in-process inspection of drilled holes in aerospace applications are described. The system measures both the general geometry of the hole (diameter, roundness, taper etc.) and the profile of the surface finish. The proposed system, based on the use of fringe-field capacitive sensors, is rapid and sufficiently rugged for in-process monitoring. Principles of analysis and design of the sensor system are presented within the context of aerospace inspection requirements. Experimental results include the direct comparison of the system with conventional metrology techniques.     

Integrated design approach for advanced aerospace vehicles

Advanced aerospace vehicle design requires special design features that should meet the mission requirements of high payload to weight ratio in the case of space launchers and low radar cross-section for specific missiles/aircraft. The conventional design packages used are discussed in relation to their constraints. An interactive integrated design approach to eliminate the constraints imposed by individual design modules through interface design modules is discussed. Typical examples of such interface design modules are given. Also, a computer network necessary for an interactive integrated design approach interfacing the mainframe with a computer-aided design and drafting system and parallel processing is presented. This note has been prepared based on detailed discussions with designers in various areas of technology.     

Steering law for roof type configuration control moment gyro system

A steering law is proposed for a roof type configuration Single Gimbal Control Moment Gyro (SGCMG) system for attitude control of the Large Space Telescope, a payload of the Space Shuttle. Although various steering laws have been developed for SGCMG systems, they have some drawbacks because of singular states of the system. The proposed steering law minimizes the effect of singular states by using a new momentum distribution scheme that makes all the singular states unstable. This scheme is formulated by treating the system as a sampled-data system.     

The use of database techniques in production control- a practical example from the aerospace industry

Over the last fifteen years Short Brothers, the Northern Ireland Aerospace Company, has developed individual batch systems handling all areas of finance and production. This has led to the typical situation of many stand along batch systems and many diverse files. These systems have grown in size and complexity both in terms of the information they hold and in the sophistication of the processing carried out. With regard to the production applications, information first enters the system when a part number in allocated in the Drawing Office, and thereafter as it progresses through Production Engineering, Material Control, Tool Design, more and more reference data is added to the files. Delivery programmes are fed in for all products and progress is monitored against those programmes. Consequently there are large files of information, some of which is duplicated and most of which, because of the standard file management techniques used is difficult to access. To find a firm basis for forward development both of central integrated batch systems and on-line systems, Shorts chose to use an Integrated Data Management System (IDMS) software package supplied by International Computers Ltd. (ICL). The paper discusses the initial central database development and where it will fit in with future distributed systems and data.     

Digital flight control design for a tandem-rotor helicopter

Methods and results in the continuing development of a digital flight control system (DFCS) for a CH-47B helicopter are presented. The helicopter is the research vehicle for the NASA VTOL Approach and Landing Technology (VALT) Program, and it equipped with comprehensive equipment for the investigation of navigation, guidance, and control requirements for future VTOL aircraft. Two control modes (attitude-command and velocity-command) are implemented, and each mode provides ‘Type 1’ response to guidance commands. DFCS design is based upon optimal estimation and control methods, which are found to provide flexible and efficient means for defining practical digital control systems.     

Shuttle orbiter guidance system for the terminal flight phase

During the terminal atmospheric flight phase, the Space Shuttle orbiter is an unpowered glide vehicle. The guidance and flight control system during this phase must control energy, flight path, and heading to align the orbiter with the runway at an appropriate altitude and speed for an unpowered landing. This paper includes (1) a discussion of functional requirements, (2) definition of the automatic guidance and control system, (3) definition of the displays for pilot monitoring and control, and (4) a discussion of the dynamic performance of the system.     

航天电磁继电器稳定时间测试方法

航天电磁继电器的回跳时间、燃弧时间、超程时间以及稳定时间可有效地反映触点接触的可靠性,是产品出厂前进行筛选试验的重要测试参数。现有的电磁继电器时间参数测试装置不能测量稳定时间。针对这一问题,提出了一种基于触点压降全波形检测的航天电磁继电器稳定时间测试方法,并研制了相应的测试装置。所提出的稳定时间测试方法,经实验证明,具有精度高、测试电路简单等优点。     

胶粘剂在航天工业中的应用

介绍了国内外航天工业用胶粘剂的主要种类、特点、研究现状及其使用情况,并对航天工业用胶粘剂的发展进行了展望。     

航天扩频测控通信系统的系统捕获

介绍了微波统一测控系统的捕获方法。同时提出了扩频测控通信系统在系统捕获中的新问题。给出了建立在扩频信号快速捕获基础上的扩频测控通信系统的系统捕获新方法。     

航天继电器加速贮存退化可靠性建模和统计分析

以某型号航天继电器为例,通过对失效机理及其接触退化规律的分析,建立贮存退化失效可靠性统计模型,给出了航天继电器接触寿命分布函数。研制了温度应力航天继电器加速贮存退化试验测试系统,可同时对多达40个继电器进行全自动的退化参数监测。试验结果表明,接触电阻的退化情况和统计分析,确定了各试验温度应力下接触电阻的分布情况,并通过最佳线性无偏估计(BLUE)法进行了参数估计,为进一步对航天继电器贮存可靠性评估和贮存寿命预测提供了参考和依据。