A compositional approach for performance certification of large-scale engineering systems

大型工程系统性能认证的组合方法安全关键工程系统的一个主要问题是使用物理系统的分析和计算模型来认证所需的稳定性和性能属性。现有的这种认证方法在处理当今大型系统中物理组件的数量及其相互作用的复杂性方面的能力受到严重限制。该项目通过一种组合方法来解决这个问题，该方法从子系统及其相互作用的关键结构属性中获得系统级保证，而不是将系统模型作为一个整体来处理。第一个目标是开发工具，自动检测子系统的有用特性及其相互联系，并利用这些特性来简化业绩认证任务。为了选择重要的子系统属性，采用了最近开发的大规模优化技术。同样，利用图论和计算代数中的高效算法来检测组件互连中的对称性，从而进一步简化。第二个目标是将上述组合方法推进到“混合”系统，其中监督控制算法能够从一种操作模式切换到另一种操作模式。接下来的任务是制定切换策略，以防止系统达到被认为“不安全”的状态。该项目的教育贡献之一是开发了一种桌面机器人系统，它模仿了翻滚游戏，在游戏中，两名玩家的目标是停留在漂浮的圆木上，同时试图让竞争对手失去平衡。该系统体现了在广泛的应用领域中非常感兴趣的基本问题，并为新的控制算法提供了试验台，例如在几种模式(防御、攻击、短期生存等)之间切换策略。另一个教育贡献是由主要研究人员正在开发的关于该项目主题的研究生课程。对于安全关键工程系统来说，缺乏可扩展的验证工具是一个主要问题，因为在这些系统中，物理组件的数量及其相互作用的复杂性不断增加。本项目通过组合的方法解决这个问题，该方法利用子系统及其互连拓扑的关键结构属性，而不是将系统模型作为一个整体来处理。第一个目标是开发能够自动检测子系统及其相互关联的关键属性的工具。这将通过利用互连拓扑中的对称性来减小用于性能验证的数值问题的大小，并通过使用大规模优化工具(例如乘数交替方向法(ADMM))来选择最重要的子系统属性来实现。第二个目标是推进上述组合方法，使之超越传统的性能标准和系统模型。新的任务包括安全验证，目标是确保没有弹道进入不希望的集合，以及设计混合系统的切换策略以维护安全。所提出的组合方法和基于半定规划的现代计算工具的结合为克服这些问题的现有维度障碍提供了巨大的潜力。私人投资机构正在开发一门以该项目为主题的研究生课程。另一个教育贡献是开发了一种桌面机器人系统，它模仿了翻滚游戏，在游戏中，两名玩家的目标是停留在漂浮的圆木上，同时试图让竞争对手失去平衡。该系统体现了在广泛的应用领域中非常感兴趣的基本分布式控制问题，并为新的算法提供了测试平台，包括那些由拟议研究产生的算法。

A compositional approach for performance certification of large-scale engineering systemsA major problem for safety-critical engineering systems is to certify the required stability and performance properties using analytical and computational models of the physical system. The existing methods for such certification are severely limited in their ability to cope with the number of physical components and the complexity of their interactions in today's large-scale systems. The project addresses this problem with a compositional approach that derives system-level guarantees from key structural properties of the subsystems and their interactions, rather than tackle the system model as a whole. The first objective is to develop tools that automatically detect useful properties of the subsystems and their interconnection, and to exploit these properties to simplify the task of performance certification. To select important subsystem properties, recently developed techniques for large-scale optimization are employed. Likewise, efficient algorithms from graph theory and computational algebra are leveraged to detect symmetries in the interconnection of the components, leading to further simplification. The second objective is to advance the aforementioned compositional approach to "hybrid" systems in which a supervisory control algorithm is able to switch from one mode of operation to another. The task is then to develop switching strategies to prevent the system from reaching states that are deemed "unsafe". One of the educational contributions of the project is the development of a desktop robotic system that mimics the logrolling game in which two players aim to stay on a floating log while attempting to cause the competitor to lose balance. This system embodies fundamental problems that are of great interest across a wide range of application areas and provides a test bed for new control algorithms, such as switching strategies between several modes (defensive, aggressive, short-term survival, etc.). A further educational contribution is a graduate course on the theme of this project that is being developed by the principal investigators.The lack of scalable tools for verification is a major problem for safety-critical engineering systems in which the number of physical components and the complexity of their interactions are continuously increasing. This project addresses this problem with a compositional approach that exploits key structural properties of the subsystems and their interconnection topology, rather than tackle the system model as a whole. The first objective is to develop tools that automatically detect critical properties of the subsystems and their interconnection. This will be accomplished by exploiting symmetries in the interconnection topology to reduce the size of the numerical problem for performance certification and by employing large-scale optimization tools, such as the Alternating Direction Method of Multipliers (ADMM), to select the most important subsystem properties. The second objective is to advance the aforementioned compositional approach beyond traditional performance criteria and system models. The new tasks include safety verification where the goal is to ensure that no trajectory enters an undesirable set, and designing switching strategies for hybrid systems to maintain safety. The combination of the proposed compositional approach and modern computational tools predicated on semidefinite programming offer great potential to overcome the existing dimensional barriers for these problems. The PIs are developing a graduate course on the theme of this project. A further educational contribution is the development of a desktop robotic system that mimics the logrolling game in which two players aim to stay on a floating log while attempting to cause the competitor to lose balance. This system embodies fundamental distributed control problems that are of great interest across a wide range of application areas and provides a testbed for new algorithms, including those resulting from the proposed research.