国外宇航级混合集成电路发展浅析

分析了美国、欧洲、日本等国家发展宇航级混合集成电路的策略、宇航标准体系和产品制造商质量体系认证等情况,详细介绍了美国Crane Interpoint、Natel公司等国际知名企业研发宇航级混合集成电路产品的概况。探讨了未来国际宇航级混合集成电路的技术和产品发展趋势,最后分析了国内外技术研究水平的差距,提出了发展中国宇航混合集成电路产品的建议。     

绳系拖拽系统半物理仿真实验装置设计与控制

为有效清除太空垃圾,模拟空间中对废弃卫星的回收过程,采用半物理实验技术对绳系收放装置进行地面试验考核,验证绳系收放控制系统的性能。半物理仿真是一种通过实物或物理模型与数学模型相结合进行仿真的技术,通过地面半物理仿真实验对空间任务进行先验,大大减少了空间实验的成本,可有效指导空间任务的设计与控制。首先,对绳系卫星拖拽过程进行动力学建模,明确了拖拽过程的任务目标,确立了绳系拖拽半物理系统的机械组成。其次,设计了全物理仿真单元为被动加载单元,卫星质量采用等效惯量转台模拟。然后,为模拟目标在绳系拖拽作用下的动力学状态,仿真加载单元由半物理仿真方式设计。最后,针对实际试验过程中存在的张力测量误差扰动,设计了基于模型预测控制的控制策略,为了对拖拽过程的张力和绳长精确控制,实验使用双闭环电机联合控制,通过模型预测控制的方式联合张力位置双电机仿真。结果表明,基于模型预测控制的张力误差精度为5%,从而验证了绳系收放控制系统对拖拽过程的控制有效性。     

含硼富燃料推进剂配方初步优化

针对含硼富燃料推进剂热值高，燃烧性能差的特点，介绍了一种低成本的含硼富燃料推进剂可燃性的实验测定方法，利用该方法对含硼富燃料推进剂三个主要组分的不同配比进行了大范围的测试。给出了含硼富燃料推进剂的可燃区间，同时发现当氧化剂含量一定时，金属燃料和粘合剂体系之间存在一个燃烧性能最佳的配比。结合该推进剂的工艺特点，给出了其燃烧性能调节的范围。     

PMR-15 processing,properties and problems—a review

The frontrunner in the race to develop a high temperature resin for use in advanced composites intended for high temperature applications is the NASA developed polyimide PMR-15. One of the key factors in the success of the material is the relatively easy processing which is due mainly to the use of the PMR approach (Polymerisation of Monomeric Reactants). Prepreg and high quality composite laminates (glass or carbon) can be prepared with ease. Laminate properties compare well with conventional epoxy based systems but thermal stability is much greater. Continuous use temperatures are in the range 280-300°C, some 150-170°C higher than epoxy systems. Applications of PMR-15 composites include aero-engines, missiles, spacecraft and military aircraft. Despite being the leading system available today PMR-15, like all materials, has a number of limitations affecting its widespread use. Included in these are reliable methods of quality control, prepreg batch to batch variability, microcracking from thermal cycling, health and safety hazards and high temperature processing. This paper reviews the present status of PMR-15 development and outlines work designed to identify and where possible overcome these limitations.     

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.