Research On Sliding Mode Control For Networked Control Systems

The networked control systems(NCSs) are the network closed loop control systems whichare connected by the sensor, controller and actuator based on the the wireless network technolo-gy to realize the control of the plant. NCSs have the advantages of flexible, easy installation andmaintenance, safe and reliable, but will also have the disadvantages of network delay, packetloss and quantization errors to affect the system performance and make the system uncertainand nonlinear. The sliding mode control is exactly a nonlinear control, and the sliding modesurface will have a complete robustness, which makes the sliding mode control as a perfect con-trol method to solve the problems of the network control system. Therefore, in this paper weuse the sliding mode control method to make further study of the networked control systems.1. For a class of sliding mode network control system. we propose a sliding mode controlmethod which can solve the network delay, packet dropout and quantization problem in thesame time. By using the Lyapunov function method, we get the conditions which can makethe network control system stable in LMI type, and also guarantee the reachability of the slid-ing mode surface. Finally some numerical examples are given to prove the feasiblility of theproposed approach.2. In this section, we propose a integral sliding mode control. Designing an integral slidingsurface and getting the sliding mode equivalent control rate to ensure the stability of system andthe reachability of the integral sliding surface. Finally, a numerical example illustrates theeffectiveness and feasibility of the integral sliding mode control method.3. We consider the quantized observer-based sliding mode control for networked controlsystems. We simultaneously solve the problem of sliding mode observer design and the slidingmode control problem of the network system under the observer state. Designing the slidingsurface and the sliding mode control rate, by using the Lyapunov function method, we getthe asymptotic stability conditions in LMI type, and the sliding mode control rate ensures thereachability of the sliding surfaces both in the state space and the estimation error space. Finally,getting the observer parameters by using the MATLAB with LMI toolbox, and the numericalexample shows that the design method is feasible.