Distributed functional observers for fractional-order time-varying interconnected time-delay systems

Our main purpose in this paper is to design distributed functional observers for a class of fractional-order time-varying interconnected time-delay systems. The contributions of this paper conclude three aspects. First, we propose novel functional observers for subsystems of the fractional-order time-varying interconnected time-delay systems. The designed distributed functional observers in this paper work for a wider class of interconnected time-delay systems in the sense that when some existing design methods cannot be applied to estimate linear functions of the state vector, the distributed functional observers in this paper can still estimate linear functions of the original state vector. Then, we establish existence conditions for the proposed functional observers. Finally, we provide effective algorithms for computing unknown observer matrices.