Hybrid partition-and network-level scheduling design for distributed integrated modular avionics systems

Distributed Integrated Modular Avionics(DIMA) develops from Integrated Modular Avionics(IMA) and realizes distributed integration of multiple sub-function areas. Timetriggered network provides effective support for time synchronization and information coordination in DIMA systems. However, inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism.To ensure such time determinism and achieve guaranteed real-time performance, system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain. This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication, and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes. Furthermore, incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost. To control such cost, this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible. Finally, two typical cases, including a simple fully connected DIMA system case and an industrial DIMA system case, are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.     

Firewire in modern integrated military avionics

High performance communications, navigation, and identification (CNI) functions on modern military aircraft are increasingly required for mission readiness. The operation of simultaneous waveforms through an integrated avionics rack of shared resources becomes a test in moving data rapidly from one signal processing stage to the next. The IEEE 1394, or Firewire, is a commercial high bandwidth bus whose 64-bit addressing and maximum 400 Mbits/second throughput satisfies this demanding military avionics interconnect need. The challenge in applying this commercial product to integrated avionics is the requirement to seamlessly add message priority encoding. By having message priorities, the slower strategic communications links will not impair the performance of higher data rate tactical communications, thereby avoiding potentially life-threatening bottlenecks. The flight environment imposes additional challenges to ruggedize the cabling between integrated avionics racks and to utilize the full capabilities of the Firewire bus. A discussion of the physical, data link, network, and transport layers, as used in avionics applications will be done. Additionally, the versatility of 1394 in military avionics with its variable channel sizes, bandwidth on demand, hierarchical addressing, and upgrade to 800 and 1600 Mbps with a 64-bit wide data path, is emphasized. Finally, system maintenance advantages of 1394's hot pluggable features are discussed, with an eye toward cost reduction on the flight line and total operational time of the aircraft avionics systems     

Using LabVIEW to provide rapid prototyping environment for theteaching of avionics systems

This paper describes a simulation environment which has been used to teach the fundamental principles of Avionics Systems to students of Systems Engineering at Loughborough University of Technology. A versatile model of a Radar System is detailed as an example and its attributes from a teaching perspective are highlighted. The generic nature of the environment is also described, as is its position within the systems life cycle     

可重构模块化机器人系统的试验研究

通过实际的功能模块装配成了一个3自由度的串联可重构模块化机器人,用计算机控制系统来验证所提出的建立可重构模块化机器人模块库理论方案的可行性,并同时验证建立的可重构模块化机器人正运动学和逆运动学数学模型的正确性.     

An environment for the integration and test of the Space Stationdistributed avionics systems

An approach is described to supplying an environment for the integration and test of the Space Station distributed avionics systems. Background is included on the development of this concept including the lessons learned from Space Shuttle experience. The environment's relationship to the process flow of the Space-Station verification, from systems development to on-orbit verification, is presented. The uses of the environment's hardware implementation, called Data Management System (DMS) kits, are covered. It is explained how these DMS kits provide a development version of the Space-Station operational environment and how this environment allows system developers to verify their systems performance, fault detection, and recovery capability. Conclusions on how the use of the DMS kits, in support of this concept, will ensure adequate on-orbit test capability are included     

Quality control in integrated navigation systems

Real-time estimation of parameter sin dynamic systems, which becomes increasingly important in the field of high-precision navigation, requires real-time testing of the models underlying the navigation system. A real-time recursive testing procedure than can be used in conjunction with the Kalman filter algorithm is presented, along with diagnostic tools for inferring the detectability of particular model errors. The testing procedure consists of detection, identification, and adaptation. It can accommodate model errors in the measurement model and dynamic model of the integrated navigation system and is optimal in the uniformly-most-powerful-invariant sense     

Progress in CMOS integrated measurement systems

Selected micro- and nano-systems developed recently at the Physical Electronics Laboratory of ETH Zurich are reviewed: (i) a fluxgate microsystem for detection of the Earth's magnetic field; (ii) a capacitive chemical sensor microsystem for detection of volatile organic compounds in air; and (iii) a parallel scanning AFM chip. The micro- and nano-systems combine sensor structures and readout circuitry on a single chip and are fabricated using industrial CMOS technology in combination with post-processing micromachining and film deposition     

Multi-objective evolutionary design of selective triple modular redundancy systems against SEUs

To improve the reliability of spaceborne electronic systems,a fault-tolerant strategy of selective triple modular redundancy(STMR)based on multi-objective optimization and evolvable hardware(EHW)against single-event upsets(SEUs)for circuits implemented on field programmable gate arrays(FPGAs)based on static random access memory(SRAM)is presented in this paper.Various topologies of circuit with the same functionality are evolved using EHW firstly.Then the SEU-sensitive gates of each circuit are identified using signal probabilities of all the lines in it,and each circuit is hardened against SEUs by selectively applying triple modular redundancy(TMR)to these SEU-sensitive gates.Afterward,each circuit hardened has been evaluated by SEU Simulation,and the multi-objective optimization technology is introduced to optimize the area overhead and the number of functional errors of all the circuits.The proposed fault-tolerant strategy is tested on four circuits from microelectronics center of North Carolina(MCNC)benchmark suite.The experimental results show that it can generate innovative trade-off solutions to compromise between hardware resource consumption and system reliability.The maximum savings in the area overhead of the STMR circuit over the full TMR design is 58%with the same SEU immunity.     

An overview of Allied-Signal's avionics development in the CIS

AlliedSignal Commercial Avionics Systems (ASCAS) and its partners have established the following business objectives: short term (forward-fit and retrofit with off-the-shelf products; co-development of integrated systems); mid term (co-production of avionics products in the CIS); long term (become an integrated element of CIS aerospace industry in partnership with local firms and to maintain the necessary focus to achieve these goals). ASCAS has formed a strategic business enterprise which is dedicated to developing the avionics market within the CIS. ASCAS was fortunate to find a joint venture partner who possesses skills that complement its present core competencies. The advantage of this business arrangement is that, while expanding their experience and expertise in the area of systems integration, they can directly benefit from the expertise and capabilities of indigenous airframe and equipment manufacturers (customer knowledge, simulation and integration experience, capable/skilled manpower)     

Period selection for integrated controller tasks in cyber-physical systems

Performance optimization of cyber-physical systems(CPS)calls for co-design strategies that handle the issues in both computing domain and physical domain.Periods of controller tasks integrated into a uniprocessor system are related to both control performance and real-time schedulability analysis simultaneously.System performance improvement can be achieved by optimizing the periods of controller tasks.This paper extends an existing model to select task periods in real-time for CPS with fixed priority controller tasks scheduled by rate-monotonic algorithm.When all the tasks can be integrated,the analytic solution of the problem is derived by using the method of Lagrange multipliers and gradient descent method is evaluated to be suitable online.To further deal with the condition that the system is overloaded,an integrated method is proposed to select periods of tasks online by selecting a subset of tasks first and then optimizing the periods for them.Experimental results demonstrate that our method yields near-optimal result with a short running time.     

DO-254标准在机载电子硬件审定中的应用

现代机载设备广泛使用了复杂电子硬件（CEH）,这对于适航性设计和审定带来了挑战。在ARJ21-700项目中,中国首次采用了RTCA DO-254作为机载复杂电子硬件的适航符合性方法,但标准的应用仍遇到许多困难。以ARJ21-700飞机机载电子硬件的审定经验为基础,梳理了复杂电子硬件的设计和审定过程,补充并解析了DO-254标准中未明确的简单电子硬件、商用现成产品（COTS）、验证标准等关键问题的审定要求,并就部分要求给出了建议的适航符合性验证方法,这些方法也在型号合格审定过程中得以初步应用。     

Uncertain multiobjective redundancy allocation problem of repairable systems based on artificial bee colony algorithm

Based on the uncertainty theory, this paper is devoted to the redundancy allocation problem in repairable parallel-series systems with uncertain factors, where the failure rate, repair rate and other relative coefficients involved are considered as uncertain variables. The availability of the system and the corresponding designing cost are considered as two optimization objectives. A crisp multiobjective optimization formulation is presented on the basis of uncertainty theory to solve this resultant problem. For solving this problem efficiently, a new multiobjective artificial bee colony algorithm is proposed to search the Pareto efficient set, which introduces rank value and crowding distance in the greedy selection strategy, applies fast non-dominated sort procedure in the exploitation search and inserts tournament selection in the onlooker bee phase. It shows that the proposed algorithm outperforms NSGA-II greatly and can solve multiobjective redundancy allocation problem efficiently. Finally, a numerical example is provided to illustrate this approach.     

模数法在铸钢件冒口设计中的应用

铸钢件需要冒口进行补缩，模数法设计冒口比较科学，即Mw≥M件及ε(V冒 V件）≤VWη冒口就有足够的液体补缩铸件，实现铸件无缩松，缩孔等疵病，保证铸件质量。     

计算机软、硬件系统在液压脉冲试验中的应用

详细阐述了在DOS环境和WOMDPWS环境下怎样利用工业控制计算机实现过程控制与测试,并结合液压脉冲试验论述了如何利用工控机及其接口板编制计算机测量与控制软件。     

测试系统硬件驱动插件机制的设计与实现

测试系统驱动插件机制是一种在不修改测试系统软件主体（平台）的情况下就能有效地对测试系统进行扩展和加强的体系结构。本文提出了一种科学合理的实现方案,并给出了一个具体案例。     

GHQF精度分析及其在组合导航中的应用

针对非线性滤波算法在组合导航系统中的应用问题,利用泰勒级数展开对无味卡尔曼滤波(UKF)、容积卡尔曼滤波(CKF)和高斯厄米特积分滤波(GHQF)三种非线性高斯滤波算法的性能进行了比较分析;基于泰勒展开的精度分析表明,UKF和CKF从四阶项开始出现截断误差,而GHQF可以逼近任意阶精度的非线性系统的后验均值;以CNS/SAR/SINS非线性组合导航系统为应用背景,对三种滤波算法的精度进行了仿真验证。数学仿真结果表明,与UKF和CKF相比,GHQF具有更高的滤波估计精度。     

基于特征点的颅面复原技术

介绍了用人工神经网络算法确定待复原颅面的软组织厚度及颅面特征点的方法。在计算机辅助颅面复原过程中,通常只能根据颅骨上少数特征点及其所在部位的法向软组织厚度的统计值进行运算。由于现有统计值指标涵盖的年龄较宽泛,导致复原结果缺乏个性。在测定待复原颅骨骨龄的基础上,通过神经网络训练,确定软组织厚度随年龄的变化规律,较精确地计算出与拟复原对象的骨龄相适应的特征点软组织厚度值,并用最小二乘法及曲面法线原理建立数学模型,计算出颅面特征点。最后用基于Delaunay三角剖分的wavelet插值法复原出面貌雏形。     

组合导航技术在可重复使用运载器再入段的应用研究

结合国内外可重复使用运载器的发展现状及各导航方法的特点,根据飞行器再入飞行段动力学方程,建立再入段飞行轨道并提出适用于再入飞行其各段的导航方法。对再入飞行中的末端能量管理段进行全面研究,设计并进行INS和INS/SAR导航滤波计算机仿真,并对仿真结果进行了误差分析。