Operability Restoration Procedure for Fault-Tolerant Digital Systems with Dynamic Redundancy

A procedure was developed to restore operability of the fault-tolerant digital systems with dynamic redundancy. A method of reconfiguration of the fault-tolerant graph, which allows one to use the redundant chords to eliminate the effect of the faulty chords of the working configurations of graph, was described. Indiscriminability of the faults of adjacent components does not inhibit restoration of operability of the fault-tolerant systems with dynamic redundancy. A procedure of single diagnosis of faulty components was developed with regard for the characteristics of the model. For some fault situations of the 2-fault-tolerant vertex 3-cube, examples of realization of the main stages of the restoration procedure—diagnosis of the faulty components and change of the working configurations—were presented.     

基于某型控制盒单板测试仪通用测试系统的研究

为了满足控制盒单板测试通用化、模块化的要求,在自动测试系统的设计中采用了虚拟仪器测控技术,提出新的设计方案;讨论了自动测试系统的功能、硬件配置、软件模块化设计、软件流程和工作原理,设计开发了基于虚拟仪器技术的通用测试系统。该系统容错能力强,通用性好,操作方便,具有良好的扩展性,对提高武器系统的可维护性和可靠性有重要的意义。     

基于RTEMS的软件容错系统设计研究

运行于空间环境中的计算机系统,受空间辐射的影响,可能会发生各种各样的错误。为了提高系统可靠性,需要对其进行容错。在本文中,首先分析RTEMS本身的特点和空间环境的特点;然后在此基础上提出基于RTEMS的软件容错系统的分层设计思想,并给出具体的层次设计过程;最后结合模拟实验验证给出容错状态下系统的性能分析。实验结
果表明,对容错系统的分层设计是必要的。     

基于某型控制盒单板测试软件的通用化设计

以某型控制盒单板测控系统研制为背景,为了满足测控系统的通用化、模块化要求,提出了通用化的设计方案;讨论了测控系统的总体结构、硬件配置、软件模块化设计、软件流程,设计研制了基于通用化思想的通用硬件测试系统;经过后期的硬件测试表明,较传统的测控系统,该系统通用性好,操作方便,具有良好的扩展性,对提高武器系统的可维护性和可靠性有重要的意义。     

不确定性连续系统具有完整性的反馈设计新方法

基于一个新的Riccati型方程的对称正定解,对于不确定线性连续控制系统,提出了 一种新的鲁棒容错反馈设计方法,利用该方法设计的闭环系统,不仅针对执行器发生故障时 具有完整性,而且关于参数不确定性具有鲁棒稳定性.该方法简单易行,并用一个示例及仿真 结果验证了该方法的有效性.     

A systematic approach to design the reconfiguration scheme of fault-tolerant systems

A general method is derived to design the reconfiguration scheme of fault-tolerant digital systems. Two tables are established during the design procedure. One is an Error Table which lists all the possible errors which can occur in the system and the other is the Truth Table which is used to assist the design of reconfiguration schemes.     

Design and Verification of Distributed Recovery Blocks with CSP

A case study on the application of Communicating Sequential Processes (CSP) to the design and verification of fault-tolerant real-time systems is presented. The distributed recovery block (DRB) scheme is a design technique for the uniform treatment of hardware and software faults in real-time systems. Through a simple fault-tolerant real-time system design using the DRB scheme, the case study illustrates a paradigm for specifying fault-tolerant software and demonstrates how the different behavioural aspects of a fault-tolerant real-time system design can be separately and systematically specified, formulated, and verified using an integrated set of formal techniques based on CSP.     

时滞关联大系统的分散鲁棒容错控制

针对不确定时滞关联大系统,提出了一种分散鲁棒容错控制方法。目的是当发生传感器或执行器故障以及具有参数不确定时,使系统仍保持渐进稳定。基于Lyapunov稳定性理论,给出了该系统在传感器失效时具有容错性能的充分条件及控制器的设计步骤,并将结果推广到执行器失效的情况。最后通过实例仿真验证了方法的正确性,并对仿真结果进行了分析。     

从LQR理论设计容错MIMO系统的方法

本文提出了从ＬＱＲ理论设计稳定容错ＭＩＭＯ控制系统的新方法，证明了通过适当选取权矩阵Ｑ或Ｒ，可以构造出在稳定性意义上对执行器或传感器的失效具有容错性能的状态反馈系统，并给了Ｑ、Ｒ的选取方法。     

网络系统的安全决策与控制: 容错博弈研究综述

安全决策与控制是保证控制系统稳定安全运行的核心支撑技术,现代网络系统在物理层面、信息层面、个体决策和监管层面分别会岀现部件损坏、网络攻击和恶意决策等完全不同类型的异常行为.鉴于此,首先总结各类异常行为的特点,指出网络系统安全决策与控制的目标与难点,强调容错博弈控制相较于其他容错控制和博弈方法的特色和优势;其次,聚焦于4个层面上的各类异常行为及其特点,阐述容错博弈控制的基本问题和思想,立足于跨层调节的思路,详细总结各类容错博弈控制的最新研究成果及其特性;再次,以集群飞行器系统作为典型对象阐述容错博弈控制的应用前景;最后,对容错博弈控制在现代网络系统中的研究方向进行展望.     

Fault tolerance in the execution of remote jobs on idling workstations

Many workstation-based distributed systems allow programs to be executed on remote idling machines for effective utilization of system resources. Usually, the control policies in these systems force a remote job be discontinued by the arrival of local jobs to guarantee the autonomy of individual workstations. Therefore, one special concern in the design of such systems is the fault-tolerant aspects for the execution of remote jobs. In the paper we discuss two control policies of workstation-based distributed systems, checkpointing and non-checkpointing policy, which support fault-tolerant execution of remote jobs on idling workstations. An analytical analysis on the reliability and mean turnaround time of the execution of remote jobs are conducted for both control policies. The optimal time interval between checkpoints in the checkpointing policy is formulated based on the given reliability and overhead of the system. In addition, several sample results derived from these analyses are compared with the outcome of corresponding simulation programs. Some observations of fault-tolerant features of each control policy are thereupon presented as guidelines for the future development of such workstation-based distributed systems.     

鲁棒容错控制系统设计

本文考虑了观测器状态反馈控制系统的容错控制问题，提出了一种对传感器失效具有完整性的控制器设计方法，进而讨论了存在参数摄动的情况，给出了鲁棒容错控制器的设计步骤并用设计实例及仿真结果验证了该方法的有效性。     

Integrated design of fault reconstruction and fault-tolerant control against actuator faults using learning observers

This paper addresses the problem of integrated fault reconstruction and fault-tolerant control in linear systems subject to actuator faults via learning observers (LOs). A reconfigurable fault-tolerant controller is designed based on the constructed LO to compensate for the influence of actuator faults by stabilising the closed-loop system. An integrated design of the proposed LO and the fault-tolerant controller is explored such that their performance can be simultaneously considered and their coupling problem can be effectively solved. In addition, such an integrated design is formulated in terms of linear matrix inequalities (LMIs) that can be conveniently solved in a unified framework using LMI optimisation technique. At last, simulation studies on a micro-satellite attitude control system are provided to verify the effectiveness of the proposed approach.     

一类不确定广义系统的分散容错控制

讨论一类不确定广义系统分散容错控制器设计问题.首先利用线性矩阵不等式(LMI)设计分散状态反馈控制器,使得广义系统执行器未出现故障时渐近稳定;接着针对广义系统的部分执行器出现故障的情况设计分散状态反馈控制器,使得闭环广义系统渐近稳定;进而利用LMI设计广义系统在分散状态反馈作用下具有完整性的容错控制器;同时对传感器故障情形设计了广义系统在分散输出反馈作用下具有完整性的容错控制器,得到了不确定广义系统关于执行器和传感器的分散容错控制器设计的方法.将所设计的控制器用于实际电子网络系统,验证了所提出方法的有效性.     

Experience with modularity in consul

The use of modularity in the design and implementation of complex software simplifies the development process, as well as facilitating the construction of customized configurations. This paper describes our experience using modularity in Consul, a communication substrate used for constructing fault-tolerant distributed programs. First, Consul is presented as a case study of how modularity is feasible in both the design and the implementation of such systems. Secondly, general lessons about modularity in fault-tolerant systems based on our experience with Consul are given. Issues that are addressed include deciding how the system is divided into various modules, dealing with problems that result when protocols are combined, and ensuring that the underlying object infrastructure provides adequate support. The key observation is that the modularization process is most affected by dependencies between modules, both direct dependencies caused by one module explicitly using another's operation and indirect dependencies where one module is affected by another without direct interaction. Although our observations are based on designing and implementing Consul, the lessons are applicable to any fault-tolerant distributed system.     

Fault tolerance and digital systems

The paper surveys recent techniques for incorporating selftest and fault-tolerant features into digital systems and comments on their applicability to designs containing VLSI components, such as microprocessors and microcomputers. In particular, the paper covers coding techniques and the design of totally self-checking code checkers; the design of fault-tolerant computer subsystems such as clock generators and semiconductor memory; and techniques for including built-in test facilities and the development of self-test checkout routines. In conclusion, it is suggested that the next major area for research must be the design of fault-tolerant software.     

Improving reliability of cooperative concurrent systems with exception flow analysis

Developers of fault-tolerant distributed systems need to guarantee that fault tolerance mechanisms they build are in themselves reliable. Otherwise, these mechanisms might in the end negatively affect overall system dependability, thus defeating the purpose of introducing fault tolerance into the system. To achieve the desired levels of reliability, mechanisms for detecting and handling errors should be developed rigorously or formally. We present an approach to modeling and verifying fault-tolerant distributed systems that use exception handling as the main fault tolerance mechanism. In the proposed approach, a formal model is employed to specify the structure of a system in terms of cooperating participants that handle exceptions in a coordinated manner, and coordinated atomic actions serve as representatives of mechanisms for exception handling in concurrent systems. We validate the approach through two case studies: (i) a system responsible for managing a production cell, and (ii) a medical control system. In both systems, the proposed approach has helped us to uncover design faults in the form of implicit assumptions and omissions in the original specifications.     

具有数据包丢失的网络控制系统主动容错控制

在保证稳定性的前提下,研究具有数据包丢失的网络控制系统主动容错控制问题.基于一类包含马尔可夫丢包过程的网络控制系统模型,考虑了执行器可能失效的情况.利用Lyapunov稳定性理论和线性矩阵不等式方法,获得了系统的保性能被动容错控制器.从控制性能的角度考虑,针对不同的执行器失效模式,得到了丢包网络环境下系统的主动客错控制器的设计方法.数值示例表明,该控制器设计方法是有效的.     

A Rigorous Approach to Fault-Tolerant Programming

The design of programs that are tolerant of hardware fault occurrences and processor crashes is investigated. Using a stable storage management system as a running example, a new approach is suggested for specifying, understanding, and verifying the correctness of fault-tolerant software. The approach extends previously developed axiomatic reasoning methods to the design of fault-tolerant systems by modeling faults as being operations that are performed at random time intervals on any computing system by the system's adverse environment.