Stability, stabilization and experiments for networked control systems with random time delay

It is well known that the stability and performance of a networked control system (NCS) are strongly affected by the transmission delay, which is usually random in communication networks such as Ethernet. In order to cope with the random transmission delay and increase the control performance, a novel switching control approach for NCS is proposed. The random transmission delay is modelled by a Markov process. A controller, which is able to monitor the transmission delay and synchronously switches with the delay, is considered. The resulting closed-loop system is a Markovian jump linear system (MJLS) with random delay. In this paper a delay-dependent stability condition for stochastic exponential mean square stability is derived by using a Lyapunov-Krasovskii functional. The controller design algorithm for a switching controller is proposed. Experiments with the 3 degree-of-freedom (DoF) robotic manipulator ViSHaRDS show the validity of the proposed approach. An alternative non- switching approach with buffering strategy at the controller side is considered. The experimental comparison with the non- switching counterpart indicates performance benefits for the proposed switching control approach.