Shared technologies: a new roadmap

The long-term goal of the USAF Shared Technologies Program is to facilitate the development of a roadmap for technology insertion on the wide variety of legacy Automatic Test Equipment (ATE) accumulated by the USAF over the past 30 years. A successful roadmap will provide for Operation & Support (O&S) cost reduction, preserve Test Program Set (TPS) development investments, and evolve in concert with the DoD Executive Agent for Automatic Test Systems (ATS) initiatives and commercial industry, and (e.g., NxTest) changes. The near-term objective of this phase of the USAF Shared Technologies Program is to demonstrate the feasibility of incorporating available commercial technology into the Radio Frequency (RF) Mobile Electronic Test Set (RFMETS). The RFMETS was originally delivered to the USAF during the early 1990s and is used to support a variety of C-130 avionics including the APQ-170 and APQ-180 Radar Systems.     

Smart test program set (TPS)

The Boeing Company has several research and development efforts focused on improving interoperability of the test station with other external systems as well as the interoperability within the test station itself. This includes integrating UUT data, test set-up, test execution, test results, repair and replace actions with other systems to provide a "closed-loop" system. One example of the "closed-loop" system is a non-intrusive tool referred to as Smart TPS (Test Program Set). Smart TPS will provide informational services to the user that reduce diagnostic test times and provide an ordered list of replacement actions based on historical data. Where possible, data are exchanged via the automatic test markup language (ATML).     

Flyable fiber-optic radar target generator

Airborne radar relies on Built-in-Test (BIT) for fault detection, fault isolation and system calibration. The capability of BIT is often limited by space, weight, size and cost considerations. Furthermore, the radar does not have a test target that will allow BIT to perform in flight, closed-loop functional test of the complete radar system. This paper describes a fiber-optic based radar test target unit that provides a delayed replica of the transmitted radar signal. The unit will intercept a small amount of radar-transmitted energy, delay it in the fiber, then feed it back into the radar producing a calibrated “echo” at a predetermined radar range. The unit can be installed as part of the airborne radar. The details on the design and testing of a proof-of-concept unit are also given     

Next generation functional test program development system

While superior-quality functional board test has been a goal for most high reliability electronics manufacturers, the time and effort for generating such test programs using today's tools and processes makes this difficult to achieve in a cost effective manner. This paper will introduce a revolutionary approach to functional board test program development that combines the comprehensiveness of software-based simulation with the speed and simplicity of hardware emulation. The result is a functional Test Program Set development system that can produce high fault coverage, diagnostic test programs in a fraction of the time it takes using traditional techniques, and at a lower unit cost. In this paper we will first provide a brief background on the strengths and weaknesses of current software and hardware TPS development techniques-simulation hot mock-up. Next, the new approach is described in detail and contrasted against the existing techniques. Finally, actual experience to date using a prototyped system is presented     

A manager's guide to TPS first article acceptance testing

This paper offers insight into the challenges of First Article Testing (FAT) for Test Program Sets. While FAT represents a successful culmination of extensive development effort, this success comes only with advanced planning and buyer/seller cooperation. This paper emphasizes FAT challenges and their resolution. The paper is written against a real-world contract backdrop, and the problems encountered were real and representative of the generic challenges. The lessons imparted can provide valuable guidance to buyer and seller in a Test Program Set contract sell-off. For the lessons learned to be useful, however, they must be applied prior to FAT, and must result in effective, preemptive, bi-partisan management action. FAT is typically the end result of millions of dollars of expenditure and equivalent technical and emotional investment. It offers only two outcomes: “win-win” or “lose-lose”. This paper is intended to assist a win-win result     

Role of BIT in support system maintenance and availability

The role of built in test (BIT) in electronic systems has grown in prominence with the advances in system complexity and concern over maintenance lifecycle costs of large systems. In an environment where standards drive system designs (and provide an avenue for focused advancement in technology), standards for BIT are very much in an evolutionary state. The reasons for advancing the effectiveness of BIT include reduced support overhead, greater, confidence in operation, and increased system availability. The cost of supporting military electronic systems (avionics, communications, and weapons systems) has driven much of the development in BIT technology. But what about the systems that support these end items that contain test and measurement instrumentation - such as automatic test equipment (ATE), simulators and avionics development suites? There has also been a beneficial effect on the maintenance and availability of these systems due to the infusion of BIT into their component assemblies. But the effect has been much more sporadic and fragmented. This paper looks at the state of BIT in test and measurement instruments, explain its affect on system readiness, and present ideas on how to improve BIT technologies and standards. This will not provide definitive answers to BIT development questions, since the factors that affect it are specific to the instrument itself. The topics covered in this paper are: definitions of built-in test, instrument BIT history, importance of BIT fault coverage and isolation in support systems, overview of BIT development process issues that limit the effectiveness of BIT Standards related to instrument BIT, making BIT more effective in support system maintenance and availability and conclusions.     

基于Vague集相似度量的航空发动机故障诊断的研究

针对传统故障诊断的局限性,探讨了基于Vague集相似度量的航空发动机故障诊断的方法.将Vague集之间的相似度量与发动机故障诊断问题结合.在得到发动机故障征兆和故障类型之间关系的基础上,计算待诊断检测故障样本与系统故障知识的Vague集之间的相似度,从而对故障进行诊断和排序.通过实例阐明将其用于某型航空发动机的故障诊断中,结果表明该方法操作方便,诊断结果准确可靠.说明了基于Vague集相似度量在航空发动机故障诊断中的有效性与合理性.     

An Approach to Built-In Testing

The archiitecture and justification for an approach to built-in testing (BIT) in electronic circuits and systems is presented. The proposed system is capable of on-line fault detection and prediction up to the shop replaceable assembly (SRA) level and is designed to interface with external automatic test equipment (ATE) for off-line fault diagnosis within the SRA. The constituent parts of the BIT system have been extensively simulated and the approach appears to be suitable for hardware implementation both with respect to computational and economic considerations.     

机内测试虚警分析和控制

现代飞行器广泛采用机内测试(Built-intest,BIT)技术,以便对其内部故障进行自动检测、诊断和隔离,但是常规BIT面临诊断能力不足和诊断模糊性等问题,导致BIT虚警率高,难以有效发挥其应有的作用.本文论述了BIT虚警的基本理论、虚警的危害及现状,并从BIT虚警产生的原因分析入手,提出了解决虚警问题的一些方法和措施.     

Improving Avionics Fiber Optic Network Reliability & Maintainability

Work is ongoing at NAVAIR to understand how avionics fiber optic BIT technology can help reduce military aviation platform fiber optic network life cycle and total ownership cost. Operational availability enhancements via comprehensive supportability programs combined with keen attentiveness to reliability and maintainability metrics are driving the avionics fiber optic BIT value proposition. Avionics fiber optic BIT technology is expected to reduce failure rate and mean time to repair by predicting link failure before link failure actually occurs, running post-maintenance stress screening upon aircraft start-up, improving fault isolation by reducing the troubleshooting ambiguity zone from three to one, and reducing the need for separate support equipment for system troubleshooting     

Proposal to TPS delivery in 4 months?

Decreasing the often lengthy Test Program Set (TPS) development time is a high priority for both DoD and commercial industry. A protracted test development time for a commercial product can make or break its success. It can impact time-to-market goals for a product, which in turn, can result in a loss of market share. Though the DoD world has different objectives, they, too, are concerned with long test development times which can increase costs and jeopardize a weapon system's mission readiness. The case study for this paper is a test system developed by BAE Systems in less than four months to meet a commercial customer's stringent schedule requirements. The factors that contributed to the success of this project are examined, as is their relevance to the DoD world. The desire is to apply relevant lessons learned from the commercial industry to DoD programs, yielding a decrease in TPS development time     

Smart BIT: a plan for intelligent built-in test

A major factor influencing the readiness of today's highly electronics-driven weapons systems is the amount of time spent maintaining them. The attainment of a better understanding of the causes for intermittent and other ill-defined failure modes and development of a greater appreciation for the effect of both external and internal environmental factors on the fault behavior of electronic systems will help to improve the BIT (built-in test) performance. Smart BIT is the name applied to a program of research and development sponsored by Rome Air Development Center (RADC) to investigate, develop, and apply artificial-intelligence (AI) techniques to effect BIT improvement. An overview of that program, its contents and purposes is provided. Deficiencies in current BIT implementations and potential benefits of the Smart BIT program are presented. Components of this approach are discussed and supporting technology areas highlighted. The current plan for implementing this approach is given along with a scenario describing its potential form     

基于.NET的小型涡扇发动机故障判读系统设计与实现

针对某小型涡扇发动机试车数据的故障判读与诊断问题,应用先进的数据库管理技术建立并设计了发动机异常监视和故障诊断系统,包含试车数据异常监视与试车故障诊断2大功能模块.该系统依托.NET开发平台框架,采用以Web技术为中心的B/S(Browser/Server)结构,以Oracle 10.0g作为试车故障信息数据库,同时按照系统的功能需求实现不同试验模式下试车数据故障诊断.试验验证表明:该系统能有效实现发动机性能、控制参数的异常判读和故障诊断.     

基于ATE与BIT组合的NAMP自动测试与故障诊断系统设计

在对机械电气系统状态监控处理机(NAMP)功能、组成、BIT和ATE测试接口等进行测试需求分析基础上,基于ATE系统平台完成了NAMP的自动测试原理和测试流程设计,采用BIT和ATE组合测试技术完成了NAMP的自动测试,采用故障树法完成了NAMP的故障诊断功能。经故障注入实验和使用验证表明,该系统具有测试内容全面,故障定位准确,故障隔离率高等特点。     

Detection and diagnosis of sensor and actuator failures using IMMestimator

An approach to detection and diagnosis of multiple failures in a dynamic system is proposed. It is based on the interacting multiple-model (IMM) estimation algorithm, which is one of the most cost-effective adaptive estimation techniques for systems involving structural as well as parametric changes. The proposed approach provides an integrated framework for fault detection, diagnosis, and state estimation. It is able to detect and isolate multiple faults substantially more quickly and more reliably than many existing approaches. Its superiority is illustrated in two aircraft examples for single and double faults of both sensors and actuators, in the forms of “total”, “partial”, and simultaneous failures. Both deterministic and random fault scenarios are designed and used for testing and comparing the performance fairly. Some new performance indices are presented. The robustness of the proposed approach to the design of model transition probabilities, fault modeling errors, and the uncertainties of noise statistics are also evaluated     

基于虚拟仪器的无人机故障诊断系统设计

介绍了一种基于虚拟仪器的无人机故障诊断系统,给出了系统的硬件及软件组成,并就故障诊断的原理及软件实现方法做了介绍。该系统可方便实现对无人机现场故障的检测和诊断,具有良好的使用性能和价值。     

飞行控制计算机模拟接口BIT电路设计及仿真

随着航空电子设备维修性要求的提高以及设备本身要求具备检测隔离故障的能力以缩短维修时间,机内测试(BIT)在测试领域研究中将越来越重要。功能电路BIT系统是航空电子设备整机BIT系统的重要组成部分,因此从解决实际问题出发,针对飞行控制计算机中的模拟输入和输出接口电路,提出了几种BIT的设计方法,并使用Multisim软件对所设计的BIT监测电路进行仿真,仿真结果表明,所设计的BIT电路是可靠及有效的。     

Printed circuit board diagnosis using artificial neural networksand circuit magnetic fields

Testing of electronic systems using conventional testing methods has become more difficult and costly as these systems have become more complex and compact. Conventional testing methods and systems often require lengthy analysis to define testing strategies. These test systems may require lengthy test periods, complex stimulus and measurement instrumentation as well as complicated fixturing. The results are often ambiguous and require further interpretation. This paper presents an exploration of a “non-intrusive” test method based on interpreting changes in the magnetic field close to a Printed Circuit Board (PCB). Currents moving between devices on the PCB produce these magnetic fields. Changes of the PCB operational status due to faults cause changes in the associated magnetic field pattern that can be interpreted by Artificial Neural Networks (ANNs) for fault identification. An apparatus to collect magnetic field measurements is described along with some problems of collecting data. Typical magnetic field patterns for “known-good” and faulted PCBs are presented. Possible extensions of the method are discussed. This paper resulted from internally funded work at Southwest Research Institute (SwRI) concerning non-intrusive diagnostic techniques     

Test results judgment method based on BIT faults

Built-in-test(BIT) is responsible for equipment fault detection, so the test data correctness directly influences diagnosis results. Equipment suffers all kinds of environment stresses, such as temperature, vibration, and electromagnetic stress. As embedded testing facility, BIT also suffers from these stresses and the interferences/faults are caused, so that the test course is influenced,resulting in incredible results. Therefore it is necessary to monitor test data and judge test failures.Stress monitor and BIT self-diagnosis would redound to BIT reliability, but the existing antijamming researches are mainly safeguard design and signal process. This paper focuses on test results monitor and BIT equipment(BITE) failure judge, and a series of improved approaches is proposed. Firstly the stress influences on components are illustrated and the effects on the diagnosis results are summarized. Secondly a composite BIT program is proposed with information integration, and a stress monitor program is given. Thirdly, based on the detailed analysis of system faults and forms of BIT results, the test sequence control method is proposed. It assists BITE failure judge and reduces error probability. Finally the validation cases prove that these approaches enhance credibility.     

Year 2000 impact on automated testing

Both US military and industry rely on automatic testing to verify the quality of manufacture and repair. Many testers still rely on computers designed and manufactured in the early 1980's. This includes systems using embedded controllers. Year 2000 problems can surface in computer operating systems, compilers, test programs, and in embedded systems. Until the impact of the Y2K “bug” is addressed, the risk of test program failure is unknown in most legacy automatic test systems. Problems may include embedded controllers in proprietary designs, old operating systems, and unique test program code. This paper will address the potential problem areas in automatic testing, and suggest an approach for determining the best course of action. In order to evaluate the impact, a complete systems inventory must be done to identify all potential sources of problems. Little attention has been paid to the legacy automated test systems and the potential impact of the Y2K problem on such systems. Although newer systems are less likely to be affected, no one can be sure until a complete inventory and test has been accomplished