Secure and Resilient Control of Constrained Cyber-Physical Systems Subject to Network Attacks

信息物理系统（CPS）体现了基于网络的通信、软件、传感器和物理过程之间的紧密集成，它们有望在未来工程系统的设计和开发中发挥重要作用。旨在破坏伊朗核浓缩工厂运作的Stuxnet恶意软件和影响乌克兰电网的industriyer恶意软件是影响CPS的网络攻击的两个例子。******目前的研究表明，针对攻击下CPS的鲁棒和弹性状态估计问题，已经提出了许多解决方案，但很少提出控制修复策略来确保受状态和输入约束的工厂的安全。经典的容错和网络化控制解决方案能够保证工厂安全，防止特定的物理故障和网络问题。然而，他们没有能力面对恶意的对手。另一方面，网络安全工具本身不足以处理CPS，因为它们没有意识到网络攻击的物理影响。因此，需要新的CPS安全性和弹性方法来克服现有的方法。******该项目的长期目标是研究有前途的想法和解决方案，以便在通信渠道受到网络攻击的情况下对受限的CPS进行安全和有弹性的控制。从方法学的角度来看，将开发新的模型预测控制（MPC）方案来处理受限的植物和攻击场景。短期内将面临不同的关键研究挑战：网络攻击的建模和表征，集论估计工具的开发，以及能够协调检测和减轻攻击的统一控制体系结构的设计。***开发的控制方案将负责识别网络攻击并确保工厂的弹性。只要涉及到识别问题，首先将攻击者可用的信息和资源集进行特征化，以识别攻击向量和破坏性资源。然后，基于水印思想，开发了主动集论状态估计模块，以防止不可检测的攻击。物理对策将通过诉诸网络健壮的MPC工具获得。******本研究提案的主要创新方面是：联合检测和减轻网络攻击的能力，无论发生任何可接受的攻击，工厂约束都能实现，以及由此产生的控制算法的实时可承受性。******拟议研究的结果将对能够提高未来工程系统安全性的新型控制体系结构的发展产生重大影响，这将不可避免地对加拿大经济产生广泛影响，并将改善我们的生活方式。

Cyber-physical systems (CPS) embody a tight integration between network-based communications, software, sensors and physical process and they are expected to play a significant role in the design and development of future engineering systems. The Stuxnet malware designed to disrupt the operations of an Iranian's nuclear enrichment plant or the Industroyer malware affecting the Ukrainian power grid are two examples of cyber-attacks affecting CPS. ******State of the art shows that many solutions have been presented for the problem of robust and resilient state estimation of CPS under attacks, but few control remediation strategies have been proposed to ensure the safety of plants subject to state and input constraints. Classical fault-tolerant and networked control solutions are capable of guaranteeing plant safety against specific physical faults and network issues. However, they are not capable of facing malicious adversary. On the other hand, cyber-security tools alone are not sufficient to deal with CPS because they are not aware of physical implications of cyber-attacks. For such reasoning, there is a need for new CPS security and resiliency methods overcoming existing approaches.******The long-term objective of this program is the investigation of promising ideas and solutions for a secure and resilient control of constrained CPS in the presence of cyber-attacks on the communication channels. From a methodological perspective, novel model predictive control (MPC) schemes will be developed to deal with constrained plants and attack scenarios. Different key research challenges will be faced in the short-term: modeling and characterization of cyber-attacks, development of set-theoretic estimation tools, and design of unifying control architecture capable of detecting and mitigating attacks coordinately. ***The developed control schemes will be responsible for the identification of cyber-attacks and ensuring plant resiliency. As long as the problem of identification is concerned, first the set of information and resources available to the attackers will be characterized to identify attack vectors and disruptive resources. Then, active set-theoretic state estimator modules, based on watermarking ideas, will be developed to prevent undetectable attacks. Physical countermeasures will be obtained by resorting to networked robust MPC tools. ******The main innovative aspects of this research proposal are: capability to jointly detect and mitigate cyber-attacks, plant constraints fulfillment regardless of any admissible attack occurrence and real-time affordability of the resulting control algorithms.******The outcome of the proposed research will have a significant impact on the development of novel control architectures capable of improving the security of future engineering systems which will unavoidably have a broad impact on Canadian economy and will enhance the way we will live.