Robust MPC for networked control systems with data-packet dropouts modeled as disturbances

Nowadays, the control systems based on communication networks are used various industries such as manufacturing, automotive, aerospace, power generation and distribution, with many advantages and a couple of disadvantages. The latter can seriously affect the performances and the stability of each control system in the network and of the complex system as a whole. Moreover, it is well known that packet losses or data-packet dropouts are key factors for determining the quality of time-critical applications. As such, in this paper, the error caused by the data-packet dropouts which appear while sending the data through a communication network from the remote process to the controller and vice versa is modeled as a disturbance. Moreover, a novel methodology to find the limits of the hypothetical disturbance is proposed. Furthermore, the boundaries of the disturbances caused by the data-packet dropouts are taken into account explicitly during the designing phase of a predictive controller with inherited robustness based on flexible control Lyapunov functions. The system's input-to-state stability is guaranteed in a non-conservative way by the control algorithm. The predictive controller designed based on the proposed modeling methodology was tested on an electric power assisted steering (EPAS) system controlled through controller area network (CAN). Simulations were performed in Matlab/Simulink and the obtained results show that the modeling methodology and the control strategy are effective in achieving the desired performances.