Networked Control Systems Of Vehicle Suspension And Path Tracking Based On Hybrid Switched System Modeling

Along with the increasing structural complexity of the industry control object and the requirements of the high control accuracy, the coupling effects between the Discrete Event Dynamic System (DEDS) and the Continuous Variables Dynamic System (CVDS) during the control process become more and more obvious. The research on the hybrid system, which has attracted more and more attention during the past few years, is mainly about the particular dynamic characteristics of the system with the consideration of the coupling effects between the discrete event process and the continuous time process. For the networked control system with the communication constraint, the control performance is not only depending on the control strategy, but also the scheduling. Meanwhile, the design process would be simplified with the symbolic instruction. All the above effects would significantly make the networked control system with the communication constraint more suitable to be treated as a hybrid system. The interaction effects between the control performance and the scheduling performance are ignored if the control strategy and the scheduling are designed individually (instead of simultaneously), which would limit the networked control system’s performance. For this reason, a co-design of control and scheduling strategy based on the hybrid system modeling is proposed in the thesis. Nowadays, the networked control system has been widely applied in the automobile industry (especially on advanced automobile industry), which bring many advantages, such as achieving information sharing, simplifying wiring, cost saving, improving global reliability, and so on. In the thesis, the on-vehicle network is selected as the research background. Then, by modeling the on-vehicle network control system with the communication constraint as a switched system, the coupling effects between the scheduling sequence and the control sequence would be represented as the mathematic expression. Based on which, by applying the co-design of control and scheduling strategy, the scheduler and the controller are designed with the synthetically consideration of the control performance and the scheduling performance.Firstly, the development of the networked control system and the common problem about such area are described. The introduction of the current situation about the networked control and scheduling research, as well as the modeling methods based on the existed hybrid system are presented here. Besides, with the representation of the concept and the development about the on-vehicle network, the advantage of the on-vehicle network and some common bus applied on such network are concluded.Secondly, based on a MIMO system with communication constraint over forward path, a switched system model is developed on the basis of the periodic scheduling sequence and the hybrid system’s theory. Based on which, a LQR (Linear Quadratic Regulator) optimal control algorithm is proposed. With the developed switched system model, the optional method of scheduling sequence is proposed, which would ensure the system’s controllability and observability. The proposed method has applied on the automobile suspension system, and the control performance is well.Thirdly, the networked control system with communication constraint and time-delay is modeled as a discrete switched system, which has considered the integration of the scheduling information and control information. A co-design of the dynamic scheduling and state feedback control strategy is proposed. The proposed strategy could select the suitable control and scheduling strategy by using the prediction of the real-time system state. The strategy would provide higher robustness to the system than other common static scheduling methods. Since the optimization of the control sequence and the scheduling sequence are made simultaneously, the real co-design of the control and scheduling is achieved here. Furthermore, such strategy has applied to the path tracking control of the four-wheel steering vehicle; the control performance is also well.Finally, the conclusions got in the thesis are summarized, and the further work is also given.