A Resilient Nonlinear Observer for Light-Emitting Diode OpticalWireless Communication Under Actuator Fault and Noise Jamming

Optical wireless communication is emerging as a low-power, low-cost, and high data rate alternative to acoustic and radio-frequency communications in several short to medium-range applications. However, it requires a close-to-line-of-sight link between the transmitter and the receiver. Indeed, a severe misalignment can lead to intolerable signal fades and can significantly degrade system performance. Despite recent efforts to establish a line-of-sight (LOS) between transmitter and receiver by improving system designs and active alignment, maintaining a perfect LOS between the two sides despite the robot’s mobility remains a challenging task for cooperative autonomy. On the other hand, the optical wireless communication system is often hampered by noise jamming on the optical communication channel that reduces the system capacity of the wireless optical mobile networks. Additionally, a situation of an occurrence of actuator failures can occur due to malfunctions or high instantaneous torques of the actuator-mechanism flexible on the receiver orientation. To address this problem, we propose a novel extended state switched-gain discrete-time nonlinear observer to simultaneously estimate the actuator fault and the optical communication system’s state variables subject to noise jamming attack. Furthermore, Lyapunov function-based analysis is used to design the proposed unknown switched-gain input observer in each piecewise monotonic region of the optical communication model output functions and ensures global stability of the extended error system. Numerical simulation results are then provided to demonstrate the validity and effectiveness of the proposed extended switched-gain state observer subject to noise jamming attack on the optical communication link.