A Less-conservative Stability Criterion for Networked Control Systems with time-varying Packet Delays

Martin Steinberger*, Martin Horn

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A networked output feedback loop subject to packetized transmissions of the output signal is considered. Based on the small gain theorem, an easy-to-use stability criterion covering two important cases is presented. In the first case a packet numbering mechanism is employed whereas in the second case neither packet numbering nor synchronization between sender and receiver is assumed. The analysis makes use of acausal subsystems and deduces the optimal constant time delay with respect to the minimization of the ℓ 2 gain due to uncertain packet delays. This additional delay is then used in a nominal controller design such that additional admissible packet delay variations introduced by the network are maximized. A simulation example of a networked control system with a filtered Smith predictor illustrates the application of the proposed criterion. It is shown that the proposed novel technique is less-conservative than existing stability criteria based on the small gain theorem.

Original languageEnglish
Pages (from-to)2128–2143
Number of pages16
JournalIET Control Theory & Applications
Issue number16
Publication statusPublished - Nov 2021


  • Networked Control Systems
  • stability analysis
  • packet delays
  • variable time delays
  • small gain theorem
  • filtered smith predictor

ASJC Scopus subject areas

  • Control and Optimization
  • Human-Computer Interaction
  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Computer Science Applications

Cite this