Integral sliding mode control for nonlinear networked cascade control systems with multiple delays

In this paper, the problem of integral sliding mode control (ISMC) for a class of nonlinear networked cascade control systems (NCCSs) with multiple delays is studied. Due to the limited communication bandwidth between the networked nodes, there are multiple delays in transmission, which lead to the NCCS performance degraded or even unstable. Firstly, the model of NCCS with nonlinear disturbance and multiple delays is constructed where ISMC is introduced into this system for the first time. This paper presents sufficient condition for ensuring system stability by utilizing Lyapunov functions and linear matrix inequality (LMI) techniques. Subsequently, a collaborative design approach is employed to determine the key parameters of the state feedback primary controller and the integral sliding mode secondary controller. In order to validate the effectiveness of the proposed method, simulation experiments are conducted on a thermal power plant model. The simulation results demonstrate that the system can enter the sliding mode surface and maintain stable operation within a finite time, effectively applying the ISMC in continuous NCCS with multiple delays.