City area-traffic cooperative control method based wireless sensor network

Abstract

Using six types of nodes of radio sensors to structure four types of radio sensor networks, the invention forms cooperation in four layers, and accomplishes four functions. The said cooperation is: cooperation between section of road and vehicles; road junction and road junction; road junction and subarea; subarea and subarea. The said four functions are: using radio sensor networks to collect data of traffic flow in real time, fast and accurately; based on need of real time traffic flow, the invention selects self-contained signal control algorithm or cooperated signal control algorithm dynamically to generate optimal scheme for allocating time of signal for road junction; communication between road junction and vehicles make possible to redistribute spatial traffic flow; remote control end can control schemes for allocating time forcibly. There is good compatibility between the invention and current hardware of signal control system.

Description

technical field [0001] The invention belongs to the technical field of intelligent transportation, and relates to a cooperative control method for urban area traffic signal control. Background technique [0002] For an advanced urban regional traffic signal control system, the following points are very important: (1) Real-time system signal timing scheme according to the future traffic flow demand of the intersection; (2) Accurately predict the traffic that will arrive at a certain intersection in the next cycle Traffic, among them, two points are very critical: the length of the forecast time window and the frequency of traffic flow forecast. The length of the predicted time window is to predict how long the traffic flow will pass through the intersection before the next cycle signal timing scheme is formulated; (3) The traffic flow needs to be controlled and induced both in time and space. In addition, it is necessary to consider whether the system is easy to install, whe...

AI Technical Summary

Problems solved by technology

The disadvantages of this system are: (1) it is an offline system, and the optimization process of signal timing is completed by historical data, which cannot reflect the changes of real-time traffic flow; (2) the system does not consider the use of traffic flow guidance technology to achieve The problem of traffic flow distribution; (3) The calculation of signal timing optimization is too large, the theory of how to find the global optimal solution of signal timing has not been completely solved, and is still being explored; (4) The traffic model of the system requires a large amount of network geometry Dimensions and traffic flow information, and the collection of these information requires a lot of manpower and time; and the update of these data is also very difficult

The disadvantages of this system are: (1) As a real-time online selective signal control system, various signal timing schemes are determined in advance according to historical data, which cannot well reflect the changing needs of real-time traffic flow; (2) the detector Installed near the stop line at the intersection, it is difficult to detect the progress of the convoy, and it is impossible to carry out coordinated control between intersections; (3) It does not consider the guidance of traffic flow from space;

The disadvantages of this system are: (1) Adjusting the green signal ratio with a small step size cannot solve the impact of sudden changes in traffic flow on signal control; (2) The detector is buried in the upstream section of the intersection to predict the time to arrive at the intersection in the future The length is relatively short; (3) The signal phase has been fixed and cannot be adjusted dynamically according to changes in real-time traffic flow; (4) The use of traffic flow induction technology to redistribute traffic flow from space is not considered; (5) The system traffic model A large amount of network geometry and traffic flow information is required, and the collection of this information requires a lot of manpower and time; and the update of these data is also very difficult

Some current real-time signal control systems, such as the SCOOT system, simply assume that the change of traffic flow at intersections is a smooth changing trend, and use the average speed of all vehicles on the road section as the speed of each vehicle on the road section to reflect the real traffic. This obviously violates the real traffic situation: traffic congestion and traffic accidents often occur in real traffic, and the occurrence of these phenomena will lead to sudden changes in traffic at certain intersections, so it is assumed that the change of traffic flow at intersections is a smooth changing trend is incorrect

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