Measure of network effects for Ethernet based control systems

In this paper we study computational algorithm for measure of network effects for networked control systems (NCS). Main differences of these systems in respect to classical directly wired systems follows from phenomena such as packet dropouts and packet delays. In general such effects results in different dynamical properties of the system. Main aim of this paper is to propose a methodology and algorithms for numerical evaluation the impact of network effects for given probability of packet lost and packet delays. Measure of the network impact is calculated in frequency domain using SVD-DFT transformation of system operator defined on finite time horizon. The measure of network effects (MNE) is reduced to analysis of nonstationarity degree of NCS. The method enable quantitatively comparison of network impact for different controllers, control structures (direct, hierarchical) as well as for different control strategies. Theoretical considerations are complemented with two numerical examples.