Optimal Control Research Of Networked Control Systems Based On Information Integrality Scale

Along with the rapidly development and continuously amalgamation of Control Science, Network Technology and Computer Technology in a more decade, Networked Control Systems (NCS) have already become a new-style control system in the Control Science field. The appear of that reflect the development trend of modern science and technology, but also reflect the development trend of intercrossing, infiltrating and amalgamating in all of the science field supported by Information Science nowadays. Hence, it gets widely attention of the people and becomes increasingly the hotspot and focus problem of control science theory and application research.NCS breaks through the restriction in space position of traditional control systems, reduces the complexity of systems connecting, decreases the cost of system running and the charge of system maintenance, improve the information integrated degree. It brings a newly pattern into industry control and enterprise management police. At present, NCS has been widely used in many fields, such as remote industry control, remote physic, Aeronautics and Astronautics, remote teaching, ocean information remote sensing, weapon systems and ocean landform exploration.While the merit has been brought by NCS, the analysis and devising of NCS become much more complex due to the intervening of network. Because network is a part of close loop feedback control systems, it results in the whole systems possessing non-linear, time-variety, indeterminacy and non-integrality character. It challenges to control based on network. At present, research in NCS is mainly focus in system modeling, stability analysis and robust control. In the aspect of optimal control, especially possessing information non-integrality, the reference is less. Therefore, in the premise of sufficiently considering network characteristic, how to search and devise optimal control law and its implement arithmetic possesses significant theoretical research meaning and profound practical application merits. In this dissertation, the optimal control problem with full or large scale information integrality has been researched. The research content has been generalized in detail, as follows:1. The problem background, research content and meaning of this dissertation has been introduced. Furthermore, the research status quo of optimal control and NCS has been introduced in detail.2. Some basic problems of NCS, such as network induce delay, data packet dropout, data packet disorder, single-packet and multi-packet transmission have been discussed. Firstly, we discuss in detail the cause of network induce delay occurring and the basic factors affecting network induce delay, on the basis of that, separate the delay into short delay and long delay according to the relation of the delay and sampling period. Secondly, we discuss in detail the cause of data packet dropout occur, separate NCS into three kinds of system: possessing full scale, large scale and small scale information integrality according to the frequency of data packet dropout and its effect on system performance, on the basis of that, analyze and discuss summarily the effect on information integrality from the point of view on network proprietary, network induce delay and sampling period. Thirdly, we discuss in detail the cause of data packet disorder occur and the basic strategy solving the problem of data packet disorder. Furthermore, separate the arrival of data packet into normal arrival, forward arrival and lag arrival in long delay network according to the difference of data packet arrival affiliated with time scope. On the basis of that, analyze the scheduling of data packet, give a maintain sequence or discard strategy of data packet in difference case. Finally, we introduce simply the problem of single-packet transmission and multi-packet transmission, and discuss simply the advantage and disadvantage of multi-packet transmission.3. The optimal control problem of short delay NCS with full scale information integrality is researched. For a class of short delay NCS with clock-driven sensors, actuators and controllers and using single-packet transmission, the discrete time system model is established. On the basis of that, the optimal control law based on finite-time quadratic criteria is derived by using dynamic programming algorithm. Then, the realization problem of the law in practical is discussed and the optimal control sequence is presented by using system model. Finally, a numeric example illustrates the effectiveness of the results.4. The optimal control problem of short delay NCS with large scale information integrality is researched. For a class of short delay NCS with clock-driven sensors, actuators and controllers and using single-packet transmission, according to the difference position of data packet dropout occurs, the system is divided into three cases: only sensors node data packet dropout, only controller node data packet dropout and both. Then, the discrete time system model is established. In order to control effectively the state of system when data packet dropout occurs, a value-estimated compensating method is presented. This method can estimate the state value or control value by means of historical state vector and control vector. The optimal control law based on quadratic criteria is derived by using the method. A numeric example compares the difference of system performance by using value-estimated compensating method and having not compensating method when data packet dropout occurs, illustrates the effectiveness and correctness of the results.5. The optimal control problem of long delay NCS with full scale information integrality is researched. For a class of long delay NCS with clock-driven sensors, actuators and controllers and data packet disorder, a maintain sequence strategy is presented. Moreover, the discrete time system model is established. On the basis of that, the optimal control law based on finite-time quadratic criteria is derived by using dynamic programming algorithm. Then, the realizable optimal control sequence is devised. Finally, a numeric example illustrates the effectiveness of the results.6. The optimal control problem of long delay NCS with full scale information integrality is researched. For a class of long delay NCS with clock-driven sensors, actuators and controllers, data packet dropout and disorder, a judge method is presented. On the basis of that, according to the difference position of data packet dropout occurs, the system is divided into three cases. Then, the optimal control law based on quadratic criteria is derived by using the results of chapter 5 and the value-estimated compensating method. A numeric example compares the difference of system performance by using value-estimated compensating method and having not compensating method when data packet"judge dropout"and"practical dropout"occurs, illustrates consequently the effectiveness and correctness of the results.7. We summarize the dissertation, and prospect further research problem need to be solved.