Active buffer design method for networked control systems

The paper studies the control of networked control systems (NCS), considering controller-to-actuator variable time delays and packet dropout. The idea presented in our previous papers - to reduce delay variability in the loop by introducing buffer at the actuator - is now extended. The controller sends less frequent but more informative packets. The data in each control packet contains the control signal for the current time step as well as the sequence of predicted future control signals, next buffered at the actuator. The active buffer operation algorithm is proposed in the paper. The performance of NCS as a function of the prediction horizon and sampling period, under assumed communication schemes, is investigated. The results of simulation experiments for both unstable and stable equilibrium point stabilization of a pendulum on the cart system are presented.