Controller Design and Experimental Validation for Networked Control Systems with Time-Varying Random 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 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 time-varying random delay. In this paper a delaydependent 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 ViSHaRD3 validate the proposed approach. A benchmark non-switching approach with buffering strategy at the controller side is implemented for comparison. The experimental results demonstrate significant performance improvements by the proposed switching control approach.