Investigation of a Robust Software Architecture for Safety-Critical Applications

安全关键控制系统的软件必须高度可靠，因为故障可能造成灾难性后果。提出了一种利用满足不同功能的多个程序版本来保证这些系统超高可靠性要求的新方法。一个版本实现了系统的安全关键功能，而其他版本提供了更优化和精细的控制。每个程序都是一个通用关系，它计算一个输入的所有可能输出。系统输出从所有输出集的交集中获得，并保证永远不会违反安全关键版本。这种方法可以经济有效地评估系统的可靠性。它还有助于在非安全关键版本中使用先进的自适应和学习控制算法。该项目包括分析体系结构的属性、关系程序的语法和语义、有效的关系组合方法、经济有效的可靠性评估方法、编写、执行和动态组合关系程序的支持工具，以及使用几个问题评估不同能力的体系结构。这项研究的成功完成将为实现安全关键系统的可认证的高保证提供科学严谨和实用的方法。

Software for safety-critical control systems must be highly reliable since failures can have catastrophic consequences. A novel approach is proposed for assuring ultrahigh reliability requirements for these systems using multiple program versions that satisfy different functionalities. One version implements the safety-critical functions of the system while other versions provide more optimal and refined control. Each program is a general relation that computes all possible outputs for an input. The system output is obtained from the intersection of all the output sets with a guarantee that the safety-critical version will never be violated. This approach allows the reliability of the system to be assessed cost-effectively. It also facilitates the use of advanced adaptive and learning control algorithms for the non-safety-critical versions. The project includes analysis of the properties of the architecture, syntax and semantics of relational programs, efficient relational composition methods, cost-effective reliability assessment methods, supporting tools for writing, executing, and dynamically composing relational programs, and evaluation of the diverse-capability architecture using several problems. The successful completion of this research will result in a scientifically rigorous and practical approach for achieving certifiable high assurance for safety-critical systems.