Towards quality-of-service control of networked control systems: A switched time delay systems approach

The stability and performance of a networked control system (NCS) strongly depends on the communication quality in terms of time delay for example. According to the Quality-of-Service (QoS) concept in modern communication technology, the communication quality can be adapted to the requirements of the network application. This paper presents a first approach to conjointly control the NCS as well as the communication quality on basis of the QoS concept. We assume that the controller together with the time delay is switched to meet control and network performance objectives. Sufficient stability conditions are presented for the resulting switched time delay system based on the concept of piecewise continuous Lyapunov functions and the Razumikhin approach. Simulations and experiments validate the proposed approach.