Zhu Qixin

Uniformed model of networked control systems with long time delay

Abstract Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network among control system components. Two new concepts including long time delay and short time delay are proposed. The sensor is almost always clock driven. The controller or the actuator is either clock driven or event driven. Four possible driving modes of networked control systems are presented. The open loop mathematic models of networked control systems with long time delay are developed when the system is driven by anyone of the four different modes. The uniformed modeling method of networked control systems with long time delay is proposed. The simulation results are given in the end.

Exponential stability of networked control systems with short time delay

Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems. Based on the linear time-invariant process, the mathematic model of networked control systems is set up when the sensor and the actuator are time driven, the is event driven, and the network induced delay is not longer than a sampling period. Using the optimal control theory, the discrete optimal controller of the networked control system is designed. The structure of proposed controller is simple and convenient to use. The controller can render the networked control systems exponentially stable. In the end the simulation based on the unstable inverted pendulum is studied. The simulation results show the proposed method is effective.