Optimal Control For Networked Control Systems With Data Packet Dropout

For the hardware devices of network and network nodes become cheaper, control loops that are closed over a communication network get more and more common. Networked control systems have a very broad application prospects. Communication networks inevitably introduce time-delays and data packet drop, both due to limited bandwidth and congestion in communicating nodes and in the network. The time-delays in many systems will be varying in a random fashion. As an effect of these, the standard control theory can not be used in analysis and design of networked control systems. In particular, the optimal control problem of networked control systems considered data packet drop and stochastic communication delays is difficult to design.This thesis fist gives an outlook on the state-of-the-art of networked control systems and the basic features of networked control systems. And analyzes adverse effects for introducing assess network into control systems. Further research work about optimal control for networked control systems with data packet dropout is given later. The main contents are given as follows:1. For the sensor node and actuator node is time-driven, and controller node is event-driven, study the problem of optimal control for networked control systems with data packet-dropout. For adding the buffer into actuator node, we are able to limit the network-induced delay within one sampling period. The compensating approach is proposed to deal with data packet-dropouts. By the state compensating approach, we can estimate the present state vector according to the historical state data of the NCS with the successive data packet-dropout. At last, by using the dynamic programming algorithm and the state compensating strategy, we construct the optimal control sequence based on a discrete quadratic performance index.2. For a class of nonlinear networked control systems which the sensor node and actuator node is time-driven and controller node is event-driven, study the problem of optimal control for networked control systems with data packet-dropout. When the transmission delay is long time-delay, we establish generalized network control system model considered different circumstances of the loss of data packet. Based on the model transformation, the system with time-delay is transformed to a non-delayed system which is in the shape of non-delayed system. The optimal control sequence that based on discrete quadratic criteria derived, furthermore, an implementation algorithm of the optimal control law is given.