Assessing stability in discrete-time systems impacted by interference and state delays: An approach using ISS

• This research focuses on addressing the input-to-state stability (ISS) challenge concerning interfered digital filters. These filters incorporate considerations for state delays and saturation overflow arithmetic (SOA). By employing a novel Lyapunov function, we derive a condition that ensures the ISS of these digital filters. Moreover, leveraging this newly proposed condition, we introduce a new asymptotic stability (AS) criterion. To demonstrate the efficacy of these findings, we present two examples for validation purposes. In this study, we introduce a criterion for addressing the input to state stability (ISS) problem inherent in nonlinear discrete systems featuring state delay, saturation overflow (SO), and external interference (EI). This paper proposes three novel theorems by employing the Lyapunov function to assure the stability of the targeted discrete time systems (DTS) under complex conditions such as state delay, SO, EI and the first theorem utilizes system information more effectively by considering EI, state delay and SO, the second theorem focuses on asymptotic stability (AS) analysis of the system when EIs are zero, the third theorem proposes the system is AS when state delays are zero. These theorems impose fewer constrains additionally these conditions are demonstrated to be more relaxed and computationally less intensive to existing criteria. The advantage of the suggested technique is proven through three numerical examples and comparison research.