Anti-saturation resilient control of cyber-physical systems under actuator attacks

The security of cyber-physical systems (CPSs) against cyberattacks is essential in critical applications. Resilient control is an effective CPS security method that aims to mitigate cyberattacks in the physical domain of the CPSs. While resilient control has been investigated for different types of attacks, actuator saturation caused by cyberattacks has not been mentioned and addressed. To tackle this issue, a resilient control strategy is presented in this paper for CPSs under actuator saturation resulting from cyberattacks. It consists of an extended state observer and an anti-saturation resilient controller. The state observer estimates unknown system states and attacks, while the controller aims to resist the actuator saturation. The controller is designed by adopting Barrier Lyapunov function, Hyperbolic tangent sigmoid function, and the Nussbaum function. The CPSs with the resilient control strategy presented in this paper not only maintain their stability but also behave with enhanced resilience against cyberattacks, Case studies on a cyber-physical robotic arm system are conducted to demonstrate the effectiveness of the designed resilient control strategy.