Research Of Vehicle Following System Via Wireless Network

With the development of economy and technology, the automotive industry is developing more and more rapidly. The possession of personal cars is increasing years by years. However, an increase in the number of the possession of personal cars has also brought more and more problems. Traffic congestion and accidents are increasingly becoming a serious problem affecting people's production and life; hinder the development of socio-economic and environmental health, at the same time the quantity of highways in the domestic gradually become saturated. Now the preferred way to solve traffic problems is to rely on the vehicle autonomous platoons. The vehicle autonomous platoon can relieve traffic pressures and reduce accidents very well by decreasing the distance between vehicles to increasing traffic flow.The vehicle autonomous platoon's core idea is that each vehicle gets information from the preceding vehicle by a certain method of communication; uses the information from the preceding cars as control input to try to match the velocity and acceleration of the preceding vehicle,while maintaining a specified constant spacing. The vehicle autonomous platoon can relieve traffic pressures by reducing the distance between vehicles, and realize automatic or semi-automatic driving to improve the comfort of the driver. With the development of wireless network technology, on-board self-organizing network technology gradually becomes the preferred method of the vehicle autonomous platoon communication. Currently, the vehicle autonomous platoon researches focused on the following two aspects: First, the control methods, design appropriate control methods to make the vehicles traveling stable at a preset distance of the platoon. Second, consider the problems of the vehicle itself which impact on the stability of the system, such as actuators and fuel delays and other issues. However, when the vehicle self-organizing network technology used in the platoon controls, the issues inherent in the network control must be exist in the system, such as network-induced delay, quantization, packet loss, packet transmission of single and multi-packet transmission, etc. However, to these problems, there are little researches. This research is in the perspective of network to study the vehicle autonomous platoon via wireless network. The specific works are as follows:(1) Establish a platoon model. First, a simple analysis to the vehicle mechanics and uses the Newton's second theorem as a basis to build the model of the vehicle. Substituted the engine model into the vehicle model, eventually obtained the state-space model of the vehicle. The models built here are the basic of the next researches.(2) Vehicle autonomous platoon via wireless network with time delay. After the introduction of the network, the network induced delay inevitably exists in the system. The existence of delay will affect the stability of the system. This part of work is to design a control method to make the platoon moving stable when there exists time delay. Finally, use MATLAB simulations to demonstrate the control method.(3) Vehicle autonomous platoon via wireless network with time delay and packet dropout. In the real situation the network-induced delay and the packet dropout are existed at the same time and affect the system together. This part of research is considering both time delay and packet losses into the platoon control; design algorithms and controller enables the platoon to traveling stabilizes. Finally, use numerical simulations to verify the rationality of the control method.