Actively Compensating for Data Packet Disorder in Networked Control Systems

Abstract

Data packet disorder often occurs in networked control systems (NCSs), which, however, has not been taken into account in most literature to date. In this brief, the cause and effect of data packet disorder are analyzed, and an active compensation scheme is proposed to compensate for it. The proposed scheme is flexible to admit all the existing control approaches to be used and also derives a novel closed-loop system model of NCSs, which enables more reasonable and effective theoretical analysis of NCSs. The effectiveness of the proposed active compensation scheme is illustrated by a numerical example.

Adaptive sampling rate control for networked systems based on statistical characteristics of packet disordering

“…So far, the majority of NCSs research efforts have focused on controller design to provide sufficient stability conditions in the presence of packet disordering [5][6][7][8][9][10]. Significant works have also been reported on how to describe packet disordering, such as comparing the sampling instants of received signals [5], identifying packet disordering by displacements of packets [6,7], and comparing transmission delay [8].…”

PDV-based packet length allocation for networked control systems

“…These communication constraints typically increase the variant of the PDV, τ δ , and consequently increase the use of the static feedback gain K rather than the delay-dependent one K(k|k − τ k ) in (9). The reader is referred to [11], [14] for more details of the treatment of data packet dropout and disorder within the packet-based control framework.…”

“…Finally, the FCS as in (7) can be constructed by selecting appropriate items from the feedback gain vector K τ sc,k defined in (14).…”

“…Remark 4: The requirement of N > τ sc,k +τ δ is to ensure that the gain predictions from k + τ sc,k − τ δ to k + τ sc,k + τ δ are available from (14). A larger N results in a larger prediction horizon and thus usually provides a better system performance.…”

A non-uniform multi-rate control strategy for a Markov chain-driven Networked Control System

“…Nevertheless, some drawbacks arise when using a shared link, being the fundamental one the existence of time-varying delays when transmitting information between devices (usually, from sensor to controller and from controller to actuator) [51], [47], [24], [7]. Also, in some cases, networks introduce packet dropouts [20], [46], [8], packet disorder [32], [8], [53], and bandwidth constraints [30], [31]. Dealing at the same time with all the drawbacks involved in an NCS becomes a complex problem, and hence, some simplifying assumptions are usually made.…”