Robustly stabilising model predictive control design for networked control systems with an application to direct current motors

In networked control systems there are many network-induced imperfections and constraints: quantisation errors, packet dropouts, variable sampling periods, time-varying delays and communication constraints. The goal of this study is to provide a control design methodology that can assure the closed-loop performances of a network-controlled application, while compensating the time-varying delays introduced by the communication network. To this end, firstly, the error caused by the time-varying delays is modelled as a disturbance and a novel method of bounding the disturbances is proposed. Secondly, an one-step ahead predictive controller based on flexible control Lyapunov functions is designed, which explicitly takes into account the bounds of the disturbances caused by time-varying delays and guarantees also the input-to-state stability of the system. The methodology is then applied for a network-controlled direct current (DC) motor and the TrueTime simulations illustrate the effectiveness and robustness of the proposed delay modelling and control strategy.