Coordinated cyber-physical attacks (CCPA) have been touted as a serious threat for several years, where "coordinated" means that attackers have complete knowledge of the physical plant and status, and sometimes can even create physical defects, to assist cyber attacks, and vice versa. In recent years, these attacks have crept from theory to reality, with attacks on vehicles, electrical grids, and industrial plants, which have the potential to cause destruction and even death outside of the digital world. CCPA raise a unique challenge with respect to cyber-physical systems (CPS) safety. Historically, technologies to defend cyber attacks and physical attacks are developed separately under different assumptions and models. For instance, cyber security technologies often require the complete profile of the physical dynamics and the observation of the system state, which may not be available when physical defects exist. Similarly, existing system control techniques may efficiently compensate for the physical damage, but under the assumption that the control software and the sensor data are not compromised. There is a lack of unified approaches against CCPA. With this observation, this project focuses on the development of unified models with coherent set of assumptions, supported by integrated technologies, upon which CCPA can be defended much more effectively. To establish theoretical foundations and engineering principles for resilient CPS architectures, this project will investigate unified models and platforms that represent the scientific understanding of resilient CPS against CCPA. Engineering of CPS will be addressed through the development and integration of complexity-reduced software architectures, along with their design principles, which lead to verifiable and certifiable architectures with higher level of system resilience. Technology of CPS will be addressed through the design of new attack detection, isolation, and recovery tools as well as timing and control techniques to ensure appropriate responses to CCPA. The proposed inherently interdisciplinary research will ensure predictable performance for resilient CPS, by leveraging the disciplinary advances in (i) the design and evaluation of robust fault-tolerant control systems yielding significantly enhanced levels of safety in highly unpredictable environments; (ii) the design and implementation of complexity reduction architecture yielding a significant reduction in the verification time from hours to seconds; (iii) the development of multi-rate sampled-data control and robust reachability-based attack detection techniques ensuring that the sensor data is reliable; and (iv) the development of cyber-physical co-adaptation that optimizes control performance and computation task scheduling to guarantee system safety and efficient recovery from CCPA. The target application of this project is unmanned aerial vehicles (UAVs). The research results will be evaluated in three different testbeds: UAV testbed, generic transportation model (GTM) aircraft, and power system virtual testbed (VTB). The technological advancement from this project will provide solutions for the safety and reliability issues faced by today's CPS and deliver dependable CPS that are applicable without sacrificing functionality or accessibility in complex and potentially hostile networked environment. The results of this project will be communicated in archival journal publications, conference venues and various workshops and lectures, and will be integrated at different academic levels.

Human-robot teams engaged in transportation and data collection will often share a common physical workspace. This project will investigate fundamental challenges in human-cyberphysical-systems (h-CPS) for cooperative aerial payload transport. First, Unmanned Aerial Vehicles (UAVs) cooperatively lift and carry a payload through a cluttered environment under uncertain winds. The multi-UAV system (MUS) functions autonomously to allow human companions to focus attention on their environment while interacting with the MUS. We propose a novel interface where an operator pushes on the slung payload to guide the team and coordinates the mission through a networked tablet. A novel cooperative control strategy safely guides the MUS while physics-based algorithms distinguish human inputs from environmental disturbances. Flight tests will demonstrate and validate the h-CPS. The PI and mentored postdoctoral researcher will involve students from under-represented groups and K-12 students in safe MUS flight demonstrations. This project offers three research advances: MUS scalability and collision avoidance guarantees through continuum deformation cooperative control, safe MUS compensation for vehicle anomalies, and cognitively-tractable user interfaces. Particularly novel to this work is the h-CPS interface in which an operator pushes on the payload to guide the MUS team. We will apply linear momentum analysis to sense haptic cues and will validate our models in simulation and flight testing. Mission-level decision-making will be performed through system modeling as a Markov game in which game states are defined from human, environment, and aggregate MUS state. Our method abstracts MUS behaviors to reduce cognitive complexity and real-time network and computational overhead.