Bandwidth allocation and scheduling of networked control systems with exponential and quadratic approximations

•We investigated bandwidth allocation and scheduling of networked control systems (NCSs) with nonlinear-programming techniques.•Two nonlinear approximations, exponential and quadratic, were formulated to describe the system performance.•The time-delay effects were considered in the system performance index functions.•The optimal sampling frequencies are obtained by solving the approximations with Karush–Kuhn–Tucker (KKT) conditions.

This paper investigates bandwidth allocation and scheduling of networked control systems (NCSs) with nonlinear-programming techniques. The bandwidth utilization (BU) is defined in terms of sampling frequency. An exponential and a quadratic approximation are formulated to describe system performance versus the sampling frequencies. The optimal sampling frequencies are obtained by solving the approximations with Karush–Kuhn–Tucker (KKT) conditions. Experimental results verify the effectiveness of the proposed approximations and scheduling algorithms. The two approximations could find an optimal BU of an NCS with a given sequence of plants and maximize the total BU up to 98% of the total available bandwidth.