Event-Triggered Secure Control of Networked Cascade Systems: From Fixed Thresholds to Adaptive Mechanisms under Cyber Attacks

This monograph systematically investigates event-triggered secure and fault-tolerant control for Networked Cascade Control Systems (NCCS) under Denial-of-Service attacks, network delays, actuator faults, disturbances, and quantization errors. Progressing from continuous-time to discrete-time, single-loop to dual-loop, and ideal to quantized channels, six core contributions are presented: an improved event-triggered mechanism (ETM) with state-difference cross-term for nonlinear NCS; extension to nonlinear NCCS addressing primary-secondary loop challenges; H-infinity disturbance attenuation; a disturbance-aware adaptive ETM (AETM) for discrete-time NCS; cooperative design of AETM and controllers for discrete-time NCCS with faults and delays; and a quantized AETM with sector-bounded errors. A unified co-design framework based on Lyapunov theory and linear matrix inequalities optimizes controller gains, triggering matrices, and quantizer parameters under H-infinity guarantees. Industrial case studies on steam temperature and boiler-turbine systems validate the proposed strategies, bridging advanced control theory and Industry 4.0 requirements for resilient, efficient NCCS.