EFFECTS OF NETWORK DELAY QUANTIZATION IN DISTRIBUTED CONTROL SYSTEMS

摘要

When control loops incorporate fieldbus systems, typical quality of service parameters like delay and jitter play an important role with respect to the performance of the control. Traditionally, the desired quality of the control defined the constraints for the network. Today, it is desirable to use existing networks and make the control robust enough to cope with the deficiencies of the fieldbus. This paper investigates the influence of a network with bounded delay distribution on the performance of a discrete time control loop. We find that delays of about the sampling period give rise to a particularly sensitive behavior of the controller. Furthermore, the overshoot amplitude (as a quality indicator) seems to depend linearly on the delay distribution of the network, which offers a convenient design criterion for the controller.