Design of the simulation platform for networked control systems based on DTHMM

Abstract

In order to achieve the application of discrete-time hidden Markov model (DTHMM) in modeling and controlling the networked control system (NCS) with the network-induced delays in the forward channel, a simulation platform was designed and implemented in this paper by using TrueTime 1.5, which is a Matlab/Simulink-based simulator. There were one network module and four kernel modules (sensor, controller, actuator and interference nodes) on this simulation platform, and the composition and the main Matlab codes of each module were presented. On the simulation platform designed, the Expectation Maximization (EM) algorithm was achieved to derive the parameters of the DTHMM and the Viterbi algorithm was achieved to predict the controller-to-actuator delay (C-A delay) in the current sampling period. Based on the derived DTHMM and the predicted delays, a state-feedback controller to stabilize the NCS was also implemented on the simulation platform and used to solve the linear matrix inequalities. Taking a damped compound pendulum as the plant in the NCS, after 500 sampling periods the effectiveness of the modeling and controlling methods was carried out, and demonstrated the efficiency and easy operation of the simulation platform.