CN100337257C - Distribution-type four-stage structure traffic signal control system - Google Patents

Abstract

A distributed four-level structure traffic signal control system relates to a distributed four-level structure traffic signal control system and method applied to a regional road network. According to the design scheme provided by the present invention, the distributed four-level traffic signal control system includes a central control level, an area control level, and a key intersection control level. Among them, the central control level is the first-level control, and the main equipment is the central control machine; the regional control level is the second-level control, and the main equipment is the regional control machine, which is responsible for coordinating and controlling the key intersection control machine; the key intersection control level is the third Level control, the main equipment is the key intersection control machine, which is responsible for coordinating the intersection control machine or virtual intersection control machine; the intersection control level or virtual intersection control level is the fourth level control, the main equipment is the intersection control machine, which is responsible for controlling the traffic lights at the intersection Or off, and the virtual intersection control machine only exists in software logic, and does not exist physically.

Description

Distributed four-level structure traffic signal control system

technical field

The patent of the present invention relates to a distributed four-level structure traffic signal control system and method applied to the regional road network.

Background technique

At present, the coordinated traffic signal control system of the regional road network generally adopts a traffic signal control system with a centralized secondary structure or a semi-distributed tertiary structure. Among them, the typical representative of the centralized secondary structure traffic signal control system is the British SCOOT system, and the control structure is shown in Figure 1. The system is divided into two levels of central control and intersection control. The main equipment of the central control level is the central control machine, and the main equipment of the intersection control level is the intersection control machine, which is directly connected to the central control machine through optical fiber or cable communication channels. According to the vehicle arrival information uploaded by each intersection control unit, the central control machine adopts the data model and optimization algorithm, and finally optimizes to obtain a new control scheme (including signal cycle length, green light time ratio and green light start time difference) to generate each intersection signal light The off time is sent to the corresponding intersection control machine respectively, and the traffic lights at the intersection are controlled by the intersection control machine to turn on and off. The central control unit of the system needs to process a large amount of vehicle arrival information, and perform heavy traffic control scheme optimization calculations, communication control and operation settings. The central control unit is the core unit of the entire system and undertakes arduous tasks.

When applied to traffic signal control in large and medium-sized cities, the centralized control structure system often needs to coordinate and control hundreds or even thousands of intersection controllers at the same time. It needs to have a high computing speed and a large storage capacity, and requires many communication channels connecting the central control machine and the intersection control machine to not only need a higher communication frequency but also a higher communication quality. Only in this way can it be guaranteed normal operation of the system. Once the central control machine fails, the entire system will be paralyzed. The system with this structure has high requirements on the hardware environment and communication channels, and requires high equipment investment and communication costs.

A typical representative of the semi-distributed three-level traffic signal control system is Australia's SCATS system, and the control structure is shown in Figure 2. The system is divided into three levels of control: central control, regional control and intersection control. The central control level is the highest level of control, and the intersection control level is the lowest level of control. The main equipment of the central control level is the central control machine, the main equipment of the area control level is the area control machine, and the main equipment of the intersection control level is the intersection control machine. The regional control machine can be set in the same place as the central control machine, or it can be set up in different places, and there is a certain distribution in geography.

The intersection control machine is a special device installed at the outdoor intersection. It controls the on and off of all signal lights in all directions of the intersection, and at the same time collects and processes the arrival information of vehicles at each entrance of the intersection. The regional control machine and the central control machine are indoor equipment, and they are all high-end computers with system control software installed. The area control machine can connect up to 250 intersection control machines. The area control machine mainly completes the traffic control function. It optimizes the traffic control plan (including period length, Green light time ratio and green light start time difference) to generate the on-off time of the traffic lights at each intersection, and send them to the corresponding intersection control machine respectively, and control the on-off of the traffic signal lights at the intersection through the intersection control machine.

The central control machine is a computer that performs management tasks and can be connected to up to 64 area control machines. It maintains the database of the system and records various information such as operating configuration, operating status, and vehicle arrival information uploaded by each area control machine and intersection control machine. , for traffic managers to analyze and make decisions. In the way of communication connection, serial port and network can be used between the area control machine and the intersection control machine according to the actual application situation, and the transmission medium can be telephone line or optical fiber. The central control machine and the regional control machine are connected by network, the communication speed is faster, and the data volume is also larger.

Although the central control machine and the regional control machine of this semi-distributed control structure system share the tasks, the regional control machine still needs to coordinate and control dozens or even hundreds of intersection control machines at the same time. Analyzing and processing a large amount of vehicle arrival information, and a large amount of optimization calculation work is required to dynamically determine the control parameters such as cycle length, green light time ratio and green light start time difference. The real-time processing speed and work requirements of the regional controller are still relatively large. The requirements for the hardware environment and communication lines are relatively high, and the equipment investment and communication costs are still relatively high.

Contents of the invention

The purpose of the present invention is to seek a distributed four-level structure traffic signal control system, which can not only reduce the construction and maintenance costs of the traffic signal control system, but also realize more effective traffic signal coordination control on the road network.

According to the design scheme provided by the present invention, the distributed four-level structure traffic signal control system includes a central control level, a regional control level, and a key intersection control level. Among them, the central control level is the first-level control, and the main equipment is the central control machine, which is set in the urban traffic control center and is responsible for coordinating and controlling the area control machine; the area control level is the second-level control, and the main equipment is the area control machine. In the urban traffic control center or sub-center, it is responsible for coordinating and controlling the key intersection control machine; the key intersection control level is the third level control, and the main equipment is the key intersection control machine, which is set at the predetermined key road intersection and is responsible for coordinating the intersection control machine or virtual intersection control machine; the intersection control level or virtual intersection control level is the fourth level of control, and the main equipment is the intersection control machine, which is set at the intersection of roads and is responsible for controlling the on or off of the traffic lights at the intersection, and the virtual intersection control machine It exists only logically in software and does not exist physically.

The central control machine is connected to up to 48 regional control machines through optical fiber or cable communication channels, and each regional control machine is connected to up to 48 key intersection control machines through optical fiber or cable communication channels, and each key intersection control machine is connected through cable communication channels Up to 10 intersection controllers or virtual intersection controllers located around key intersections or on the same main road, each intersection controller or virtual intersection controller is responsible for lighting or extinguishing multiple traffic lights connected to it. Selecting a central control machine to control up to 48 regional control machines, and each regional control machine to control up to 48 key intersection control machines is mainly based on the balance of computing power, storage capacity and investment costs of the control machines. The central control machine or the regional control machine only needs to select a PC server with a CPU of P4 or above to be able to do the work, which can greatly reduce the equipment investment cost. Selecting a key intersection controller to control up to 10 intersection controllers or virtual intersection controllers is mainly based on the following two considerations: 1. The control core unit of the key intersection signal machine is an industrial control computer. At present, the high-quality and low-cost PC/104 industrial control computer can do the job, not only controlling the cost, but also has strong operational reliability; 2. The key intersection signal machine controls more than 10 intersection control machines or virtual intersection signal machines , not only the effect of coordination control is difficult to guarantee, but also the cost of communication channel construction is relatively high.

When the distance between the surrounding intersections to be controlled by the key intersection control machine and the key intersection is not more than 100 meters, no intersection control machine is installed at these intersections, and the signal lights installed at these intersections are directly connected to the key intersection control machine through control cables. When the intersection control machine is set up, the built-in software system of the key intersection control machine logically still sets up a virtual intersection control machine for these intersections, and the key intersection control machine controls the virtual intersection through these virtual intersections that do not exist physically but exist logically in the software. Machines are used to turn on or off the signal lights at these intersections.

The intersection control machine or virtual intersection control machine is based on the signal cycle issued by the key intersection and the time difference between the green light and the starting time. After the built-in control software optimizes the green light time ratio of the intersection, it generates the on-off time of the intersection signal lights and controls all signal lights in each direction. At the same time, it collects and processes the arrival information of vehicles in all directions at this intersection, and forms primary information and uploads it to the key intersection control machine.

The key intersection control machine is based on the cycle length variation range issued by the regional control machine and the primary information uploaded by the intersection control machine or the virtual intersection control machine, and its built-in control software is optimized to obtain the cycle length of each intersection connected by the key intersection control machine At the same time, the primary information uploaded by each intersection control machine or virtual intersection control machine is summarized and processed to form intermediate information and then uploaded to the regional control machine.

The regional control machine and the central control machine are indoor devices. The regional control machine has built-in control software, which mainly completes the coordination control and data processing functions. It macroscopically determines the control of each key intersection based on the intermediate information uploaded by each key intersection control machine it is connected to. At the same time, the intermediate information uploaded by the control machines at each key intersection is summarized and processed to form high-level information.

The central control machine is a computer that performs management tasks. It maintains the database of the system, records and stores and manages the operation configuration, operation status and advanced information uploaded by each area control machine and each key intersection control machine for traffic management personnel. Analyze decisions.

The present invention discloses a traffic signal control system with a fully distributed four-level control structure. First, it is decentralized in physical structure. The central control level and the regional control level are located in the same place or different places indoors. The intersection control level and the intersection control level are located in different places outdoors; secondly, they are also distributed in terms of functions. The central control machine completes the executive management task, the regional control machine completes the task of macroscopically coordinating and controlling the key intersection control machines, and the key intersection control machine completes The optimal calculation of traffic control parameter cycle length and green light start time difference, the intersection control machine completes the optimal calculation of traffic control parameter green light time ratio, and the overall workload of the system is more evenly distributed to the central control machine, regional control machine, and key intersections Control machine and intersection control machine.

Compared with the prior art, the present invention has the following advantages: 1. The system adopts distributed control and distributed information processing, optimized calculation, and requires the computing power and computing capacity of the central control machine, the regional control machine, the key intersection control machine and the intersection control machine Both are low, which can significantly save equipment investment costs. 2. The intersection control machine communicates with the key intersection control machine nearby, without long-distance access to the traffic control center or sub-center, occupies less communication line resources, and can save a lot of investment and construction costs for communication lines. 3. The system has relatively low requirements on the transmission rate and reliability of communication lines and equipment. Once the main communication line connecting indoor and outdoor equipment fails, the key intersection control machine and the intersection control machine or virtual intersection control machine will still work normally. 4. Flexible control, high reliability, more convenient installation and debugging.

Description of drawings

Figure 1 is a control structure diagram of the SCOOT system.

Figure 2 is a control structure diagram of the SCATS system.

Figure 3 is a control structure diagram of the distributed four-level system.

Figure 4 is a schematic diagram of the road network.

Figure 5 is a schematic diagram of the layout of the control equipment.

Detailed ways

The distributed four-level structure traffic signal control system includes a central control level, a regional control level, a key intersection control level, and an intersection control level or a virtual intersection control level; among them, the central control level is a first-level control, and the main equipment is a central control machine. Set in the urban traffic control center, responsible for coordinating and controlling the area control machine; the area control level is the second level of control, the main equipment is the area control machine, set in the urban traffic control center or sub-center, responsible for coordinating and controlling the key intersection control machine; key intersection The control level is the third level of control, the main equipment is the key intersection control machine, which is set at the predetermined key road intersection, and is responsible for coordinating the intersection control machine or virtual intersection control machine; the intersection control level or virtual intersection control level is the fourth level Control, the main equipment is the intersection control machine, which is installed at the intersection of roads, and is responsible for controlling the on or off of the traffic lights at the intersection. Moreover, the virtual intersection control machine only exists in software logic, and does not exist physically.

The central control machine is connected to up to 48 regional control machines through optical fiber or cable communication channels, and each regional control machine is connected to up to 48 key intersection control machines through optical fiber or cable communication channels, and each key intersection control machine is connected through cable communication channels Up to 10 intersection controllers or virtual intersection controllers located around key intersections or on the same main road, each intersection controller or virtual intersection controller is responsible for lighting or extinguishing multiple traffic lights connected to it.

When the distance between the surrounding intersections to be controlled by the key intersection control machine and the key intersections is not more than 150 meters, no intersection control machines are installed at these intersections, and the signal lights installed at these intersections are directly connected to the key intersection control machines through control cables. The use of direct connection when the distance is shorter than 150 meters is based on the balanced consideration of the traffic signal coordination effect and the investment cost of intersection equipment and communication channels. When there is no intersection control machine, the built-in software system of the key intersection control machine logically still sets up virtual intersection control machines for these intersections. Intersection control machine to light or extinguish the signal lights of these intersections.

The intersection control machine or virtual intersection control machine is based on the signal cycle issued by the key intersection and the time difference between the green light and the starting time. After the built-in control software optimizes the green light time ratio of the intersection, it generates the on-off time of the intersection signal lights and controls all signal lights in each direction. At the same time, it collects and processes the arrival information of vehicles in all directions at this intersection, and forms primary information and uploads it to the key intersection control machine.

The key intersection control machine is based on the cycle length variation range issued by the regional control machine and the primary information uploaded by the intersection control machine or the virtual intersection control machine, and its built-in control software is optimized to obtain the cycle length of each intersection connected by the key intersection control machine At the same time, the primary information uploaded by each intersection control machine or virtual intersection control machine is summarized and processed to form intermediate information and then uploaded to the regional control machine.

The regional control machine and the central control machine are indoor devices. The regional control machine has built-in control software, which mainly completes the coordination control and data processing functions. It macroscopically determines the control of each key intersection based on the intermediate information uploaded by each key intersection control machine it is connected to. At the same time, the intermediate information uploaded by the control machines at each key intersection is summarized and processed to form high-level information.

The central control machine is a computer that performs management tasks. It maintains the database of the system, records and stores and manages the operation configuration, operation status and advanced information uploaded by each area control machine and each key intersection control machine for traffic management personnel. Analyze decisions.

The embodiment is as follows: Assume that the control area of the traffic signal control system is a road network composed of 6 signal intersections as shown in FIG. 4 , and the distance between intersections is shown in Table 1.

Set intersection 2 as the key intersection in advance, set key intersection signals at intersection 2, and set intersection signals at intersections 1, 3, 4, and 6 respectively. Since the distance between intersection 5 and key intersection 2 is 100 meters, it is shorter than 150 meters , therefore do not establish intersection signal machine at intersection 5, and on the software logic of key intersection signal machine 2, virtual intersection signal machine 5 is set for intersection 5.

As shown in Figure 5, crossing control machines 1, 3, 4, 6, virtual crossing signal machine 5, and key crossing signal machine 2 are respectively connected to respective signal light groups and vehicle detector groups by power cables and control cables, and crossing control machine 1 , 3, 4, 6 are directly connected to the signal machine 2 at the key intersection through communication cables. The vehicle detector group is used to detect the traffic status of the intersection in real time and upload it to the intersection control machine directly connected to it. The traffic signal optimization module is based on the traffic status of the crossing where the signal period is calculated to make the total vehicle delay of the crossing reach the minimum value, and is sent to the built-in traffic signal optimization coordination module of the key crossing signal machine 2, which determines the common traffic of these crossings. The signal cycle and the start time difference of the green light, and then the intersection control machines 1, 3, 4, 6, the virtual intersection control machine 5, and the key intersection signal machine 2 are based on the common signal cycle, and the green light start time difference is then optimized by its built-in traffic signal optimization module The time ratio of the green light at this intersection, thereby generating the on-off time of the signal light groups at each intersection, and achieving the purpose of controlling the on-off of all signal lights in all directions at the intersection.

An area control machine is set up in the traffic command center, and the area control machine is directly connected to the key intersection signal machine 2 through an optical cable or a communication cable. The signal machine 2 at the key intersection sends information to the area control machine once every signal cycle, the content includes the common signal cycle and the traffic status information of intersections 1, 2, 3, 4, 5, and 6 within this signal cycle, and the area control machine is based on these information To determine the optional variation range of the common signal period of the key intersection control machine 2 and carry out summary analysis and processing on the traffic status information transmitted by the key intersection control machine 2, such as intersections 1, 2, 3, 4 in each signal period , 5, 6 vehicle arrival flow, occupancy rate and other traffic information.

In this case, since there is only one regional control machine, and the regional control machine is only responsible for coordinating and controlling a key intersection control machine 2, the requirements for computing processing power and storage capacity are relatively low, so it is not necessary to set up a separate central control machine. The functions of the area control machine can be completed by the area control machine. In this way, the area control machine also needs to be responsible for maintaining the database of the system, and is responsible for recording and storing information such as the operation configuration of the area control machine and the key intersection control machine 2.

Table 1 intersection distance table intersection pair 2-1 2-3 2-4 2-5 2-6 Intersection distance (m) 200 350 300(100+200) 100 450(100+350)

references:

1. Traffic Management and Control (Second Edition), edited by Yang Peikun and Wu Bing, published by People's Communications Publishing House

2. Road Traffic Control Technology, edited by Yin Hongbin and Xu Jianmin, published by South China University of Technology Press.

Claims (7)

1. A distributed four-level traffic signal control system, including a central control level, a regional control level, and a key intersection control level, which is characterized in that an intersection control level or a virtual intersection control level is added at the lower level of the key intersection control level; among them, The central control level is the first level control, the main equipment is the central control machine, which is set in the urban traffic control center, and is responsible for coordinating and controlling the area control machine; the area control level is the second level control, the main equipment is the area control machine, which is set in the urban traffic control The center or sub-center is responsible for coordinating and controlling the key intersection control machine; the key intersection control level is the third level control, and the main equipment is the key intersection control machine, which is set at the predetermined key road intersection and is responsible for coordinating the intersection control machine or virtual intersection Control machine; intersection control level or virtual intersection control level is the fourth level of control. The main equipment of the intersection control level is the intersection control machine, which is set at the intersection of roads and is responsible for controlling the traffic lights at the intersection. On or off, and the virtual intersection control machine It exists only logically in software and does not exist physically. 2. The distributed four-level traffic signal control system according to claim 1, characterized in that: the central control machine is connected to as many as 48 regional control machines through optical fiber or cable communication channels, and each regional control machine is connected through optical fiber or cable The communication channel connects up to 48 critical intersection control machines, and each critical intersection control machine connects up to 10 intersection control machines or virtual intersection control machines located around the critical intersection or on the same arterial road through cable communication channels, each The intersection control machine or virtual intersection control machine is responsible for lighting or extinguishing multiple traffic lights connected to it. 3. The distributed four-level traffic signal control system according to claim 1, characterized in that: when the distance between the peripheral intersections to be controlled by the key intersection control machine and the key intersections is not more than 100 meters, no intersections are set at these intersections The control machine connects the signal lights installed at these intersections directly to the key intersection control machine through control cables. When there is no intersection control machine, the built-in software system of the key intersection control machine logically still sets up a virtual intersection control machine for these intersections. The key intersection controller lights up or extinguishes the signal lights at these intersections through these virtual intersection controllers that do not exist physically but exist logically in software. 4. The distributed four-level traffic signal control system according to claim 1, characterized in that: the intersection control machine or the virtual intersection control machine is based on the signal cycle issued by the key intersection, the time difference between green lights and starting, and the built-in control software After optimizing the green time ratio of the intersection, generate the on-off time of the signal lights at the intersection, control the on-off of all signal lights in each direction, and collect and process the arrival information of vehicles in all directions at the intersection to form primary information and upload it to the key intersection control machine. 5. The distributed four-level traffic signal control system according to claim 1, characterized in that: the critical intersection control machine is based on the cycle length variation range issued by the regional control machine and the primary traffic signal uploaded by the intersection control machine or virtual intersection control machine. The information is optimized by its built-in control software to obtain the cycle length of each intersection connected to the key intersection control machine and the start time difference of the green light. At the same time, the primary information uploaded by each intersection control machine or virtual intersection control machine is summarized and processed to form intermediate information. Upload to the regional controller. 6. The distributed four-level traffic signal control system according to claim 1, characterized in that: the regional controllers and the central controller are indoor devices, and the regional controllers have built-in control software, which mainly completes the coordination control and data processing functions, It macroscopically determines the variation range of the cycle length of each key intersection control machine based on the intermediate information uploaded by each key intersection control machine connected to it, and at the same time summarizes and processes the intermediate information uploaded by each key intersection control machine to form high-level information. 7. The distributed four-level traffic signal control system according to claim 1, characterized in that: the central control machine is a computer that performs management tasks, and it maintains the database of the system, records and stores and manages each area control machine and each key The operation configuration and operation status of the intersection control machine and the high-level information uploaded by each area control machine are for traffic management personnel to analyze and make decisions.

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