As a major component of highway information construction, highway monitoring system is gradually attracting the attention of peers in the industry. It is understood that many units in the construction of the three major systems of electromechanical systems often only pay attention to the construction of hardware equipment, especially for software solutions. It is the lack of energy for the monitoring system to meet the actual operational needs. The contractor pays insufficient attention to this. In the built monitoring system, the external field and tunnel monitoring equipment cost a lot, but due to the simple preparation of the core monitoring software, it costs a lot of money. The construction of the monitoring system has not fully played its role, and the relevant governance departments cannot realize the functions of their command and control centers through the monitoring system. In fact, the construction of the monitoring system is an important basic work for realizing intelligent transportation in the future, and must be carefully carried out. I will now summarize some of my research experiences in this area. Communicate with your peers.
Data Acquisition The availability of all control systems must have a basis for accurate data collection. The accuracy of data collection comes from three aspects: 1. The advantages and disadvantages of the sensor equipment; 2. The stability of the data transmission system; 3. The improvement of the core acquisition data system.
As far as the highway monitoring system is concerned, the data acquisition equipment is mainly: traffic flow detection equipment, weather detection equipment, and tunnel environment analyzer. For the above-mentioned data acquisition equipment used in expressways, the single-machine equipment can basically meet the requirements of use and the performance is stable; if the transmission line is realized by the optical fiber communication system, the transmission performance is basically stable, and most of the current data collection is inaccurate. It is mainly related to the roughness of the upper core data acquisition software and the lack of understanding by the software programmers of the on-site single-machine equipment. The upper-end core data acquisition software is simple in design and does not play a comprehensive analysis role. Therefore, in the actual project implementation process, the following should be emphasized:
The vehicle detector vehicle detector has the largest number of external field monitoring equipment and the largest error. The main reason is that the technical requirements for the vehicle inspection device have not been standardized in the past. The construction unit has developed the relevant software with its own understanding, and the transmission data volume is too large. To this end, the following requirements are imposed on the function of the device and the upper software:
The vehicle detector shall have the average hourly speed, maximum and minimum speed, traffic flow, occupancy calculation, storage and output functions. All data shall not be lost due to power failure or reset of the equipment. Usually, the upper computer collects real-time data as data display and tunnel traffic congestion and congestion determination. The hourly traffic flow is used for statistical traffic flow. In order to minimize the amount of communication data, the vehicle detector only keeps the average speed per hour when the communication is interrupted. Maximum, minimum speed, traffic volume, and occupancy data to ensure accurate traffic flow history data. The time period of vehicle occupancy is calculated in 5 minutes.
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When the vehicle detector fails, the average speed, maximum and minimum speed, traffic flow, and occupancy rate of all vehicle inspections are taken as the approximate value of the weighted average of the same period for the first ten days to ensure that the traffic flow calculation is basically accurate. .
In the tunnel, according to the occupancy rate of the vehicle (generally 60%), or three consecutive vehicles passing and the speed is lower than 20Km/H to determine whether the traffic is blocked, thereby generating a warning signal and switching the camera to the police area by the attendant To determine if a traffic jam has occurred.
The weather detector and the environmental detector use the weighted average method to determine whether the environment exceeds the standard, and the alarm is generated. The threshold of the alarm should be manually corrected by the monitoring personnel to meet the actual operational needs. For road traffic control, since the real-time requirements are not high, in order to ensure the accuracy of the linkage control, the linkage of the relevant placards can be issued after manual confirmation.
The data transmission and control of the variable board are the largest, and all the data transmission of the board is transmitted through the fiber-optic Ethernet transceiver. For the board that does not use Ethernet transmission, the data can be realized as follows. transmission:
The variable clearing board should have a timed self-checking function. If the pixel is damaged, the fault point is fed back to the host computer to reduce the amount of data transmission.
The fixed display information of the placard is numbered and stored in the memory of the placard. The newly added information generates the number of the information while presetting the quotation board, and the upper computer sends the corresponding placard display information by numbering.
The linkage control scheme is only possible after the data acquisition is stable and reliable, and the implementation of a complete and rigorous linkage control scheme is possible. There are three main categories of control objects: traffic monitoring, lighting control, and ventilation control. The three systems are relatively independent and harmonized.
Traffic monitoring can be divided into tunnel monitoring and road monitoring. At present, the highway network is not developed enough. In addition to the vehicle inspection and weather detector detection, the road traffic information is also obtained through cameras, emergency telephones, road politics, etc. The monitoring sub-center reads the road vehicle inspection device and weather detection. After the alarm data is sent out, the controller usually waits for the manual input of the control command, and starts timing. The equipment controls the road traffic and mainly plays the role of information prompting and traffic diversion. At the same time, the monitoring personnel should track the road traffic information, release or release the traffic warning information in time, so that the information is released in a timely and effective manner.
The tunnel monitoring content is relatively complex, and there are many data acquisition and control devices involved. The tunnel monitoring implementation scheme is analyzed below.
When the traffic volume in the tunnel is too large or the traffic is blocked, the degree of congestion can be determined by the vehicle detector and the tunnel camera in the tunnel. After confirmation, the tunnel inside and outside the corresponding tunnel shows “tunnel congestion and safetyâ€. At the same time, if the CO concentration in the tunnel is increased and the visibility is reduced, the fan is started manually or automatically.
When the following emergencies occur in the tunnel, the monitoring center's monitor can automatically switch images and emergency phone alarms, and switch the camera image closest to the alarm emergency phone front end to the monitor and large screen projector.
Traffic jam: Generally, the data collected from the vehicle inspection device is analyzed. At this time, the camera image of the traffic jam is switched to the monitor and the large screen projector.
CO/VI super-threshold: switch the image of all cameras of the CO/VI super-threshold hole to the monitor, switch the 4 camera images closest to the CO/VI alarm device to the DVR, and the 4 cameras closest to the alarm device The image switches to the big screen.
Fire alarm: Switch the image of all cameras in the fire tunnel to the monitor, switch the 4 camera images closest to the fire alarm to the DVR, the 4 camera images closest to the fire alarm and the camera at the tunnel square at both ends The image switches to the big screen.
The tunnel lighting control scheme includes normal weather, fire, traffic accidents, power outages, and various weather conditions under light intensity detection, and the lighting level of each time of day.
Lighting control during fire: In the event of a fire, the lighting control system will maximize the tunnel lighting regardless of the current state of the lighting.
The lighting system normal control scheme has two methods of time control and automatic control of tunnel light intensity detection in terms of control implementation. For the lighting group, it can be divided into two parts: the reinforcement section, the transition section lighting group and the basic section group.
Time control method: according to the field test. According to different seasons and time, the day is divided into several time periods and combined with the instantaneous changes of conditions such as meteorological conditions and traffic forms, different numbers of light groups are hierarchically turned on in different time periods, or the brightness of each group of lights is adjusted.
The automatic control scheme light intensity detector reading is controlled in combination with meteorological conditions and the set value determined by the monitoring computer. At this time, the data collection and analysis of the light intensity value should be correct. If taking 3 minutes according to the detection period, take the weighted average of the first 5 acquisitions as the light intensity value, and increase or decrease the tunnel lighting comprehensive control to one level each time, so as to avoid the driving safety caused by the sudden change of illumination.
Among them, the lighting group is located at the entrance of the tunnel, and the light intensity outside the hole is transferred to the light intensity of the basic lighting group in the hole. Therefore, the focus of control should be on the reinforcement section of the section and transition section. In view of the various tunnel lighting control schemes that have been practically applied, the control of the transition lighting group will be based on the tunnel light intensity detection control and the time control as the auxiliary control measure.
The basic lighting group is a lighting group other than the reinforcement section and the transition section lighting group, which is established to maintain the basic visible illumination in the cave. Its control should basically follow the principle of power saving. For the control of the basic lighting group, time control should be taken as the main control, and the tunnel light intensity detection control should be supplemented by the control measures.
The perfection of tunnel lighting control involves the realization of lighting control technology and the choice of tunnel luminaires. It is a more complex subject and requires a comprehensive solution to ensure safe and energy-saving operation.
Tunnel ventilation control: The monitoring sub-center computer system reads the status information of CO, VI detector and fan to realize the control of starting and closing the fan. The fan introduces fresh air outside the tunnel into the tunnel and eliminates harmful gases outside the tunnel to ensure the tunnel. The concentration of smoke and CO in the solution reached the agreed value. In the event of a fire in the tunnel, it can control the spread of smoke in the tunnel to ensure the safety of the person and the tunnel.
The ventilation control scheme includes normal operation, high CO/VI, fire condition, and operation schemes such as fan opening, stopping, forward rotation, and reverse rotation under traffic accident conditions.
The normal situation ventilation control scheme is based on the National Highway Tunnel Ventilation Lighting Design Code. The CO concentration value in the tunnel is generally 200 (or 250) ppm and 300 ppm as the alarm threshold, and two alarm levels are set. However, in actual operation, it is found that even if the tunnel air human body feels that it is unbearable, the CO concentration value is still less than 150ppm. At this time, the system cannot perform automatic alarm. Therefore, in actual implementation, the CO concentration threshold should be set far. Less than 150ppm, set at 50ppm. The same problem exists with the alarm threshold setting for visibility. Therefore, the setting of the CO/VI alarm threshold in the monitoring software should be adjusted according to the actual situation and simultaneously refer to the shape of the tunnel as described above, downhill, corners and the environment observed by the camera. To this end, the fan should be controlled according to the traffic status, the value of the environmental parameters and the rate of change. The control period can take about 10 minutes. When the CO value exceeds the set value or the smoke concentration exceeds the set value, the monitoring system can control to open a group of {each set temporarily set to 2 sets) or multiple sets of fans to control the environmental parameters to meet the index requirements. In fact, in the small traffic flow, downhill tunnel, the tunnel air quality meets the driving requirements, the focus of monitoring should be concentrated on the traffic flow, uphill, and curved tunnel.
The visibility measurement range in the tunnel is O 151/Km, and the range of VI measurement values ​​is divided into 4 levels as needed. That is, the VI value of 31/Km, the VI value of 51/Km, the VI value of 71/Km, and the VI value of 101/Km are normal when the visibility is VI51/Km, and the fan in the tunnel does not start: when the visibility of the 51/Kin is VI101/Km, according to It is necessary to start the fan of the corresponding road section of the tunnel until the visibility returns to normal: when the visibility is VI101/Km, the control system will close the tunnel.
When the long tunnel has more slopes and more traffic, the VI visibility value will often exceed 5, and the VI threshold can be adjusted according to the actual situation. Generally, it is more suitable for 10-15.
Tunnel fire control scheme Fire accidents are the highest level event and the focus of tunnel monitoring. We will list them separately here, and the linkage of all related equipments will be described here.
The fire situation in the tunnel is complicated. If the location of the fire point, the length of the tunnel, the cross hole of the vehicle, and the design of the cross-hole of the pedestrian are different, the fire control scheme is different. The following provides a solution to the long tunnel of about 2 kilometers.
When a fire occurs in the tunnel, the tunnel fire alarm system alarms, the monitoring center controls the computer alarm, and the on-duty personnel determine whether a fire has occurred. After confirmation, the corresponding control command is issued to the tunnel. When the data acquisition control unit receives the processing command from the monitoring system to send the device, it immediately controls the traffic monitoring device and the fan lighting device.
The ventilation and smoke control scheme design for tunnel fires must consider the fire situation and its countermeasures, according to the tunnel length, plane curve radius, longitudinal slope, traffic conditions, natural and environmental conditions and fire risk. Tunnel fire treatment is divided into four stages, namely fire confirmation, escape, rescue, and fire suppression. In the fire confirmation and escape phase, due to the initial stage of the tunnel fire. The upper part of the tunnel is completely layered smoke, and the lower part is the fresh air flow from the hole to the fire. It is still beneficial for people to escape. At this time, the fan around the fire point should stop working to avoid disturbing the smoke and fresh air, but other The fan exhausts at a low speed. In the fire rescue phase, the exhaust fan should be turned on at full speed, and the direction of exhaust should be the same as that of the tunnel. The other fan is partially opened for air supply to prevent smoke from entering another tunnel. When the fire is extinguished, the fans of both tunnels are all Open. The specific processing is as follows:
After the fire alarm system receives the fire alarm, the tunnel camera switches all the images of the fire tunnel to the monitor after receiving the fire occurrence information. The four images closest to the fire are switched to the large screen projector and switched to the hard disk recorder. Video.
After the firefighting stage monitoring personnel confirmed the fire after the image, they immediately contacted the relevant departments of the rescue, fire fighting, traffic guidance, and other superiors to carry out fire fighting and rescue work. The basic control plan is as follows:
1. The upstream lane light of the fire tunnel shows “׆and the downstream shows “↓â€.
2. The content of the fire tunnel tunnel is set as: “Tunnel fire, no trafficâ€.
3, the content of the side hole board is set to: "slow down."
4. The fan around the fire point is closed, and a group of fans upstream of the fire is turned forward.
5. The tunnel lighting that caused the fire is fully open.
The side hole fan starts the corresponding fan according to the fire point of the fire to prevent the smoke from spreading to the side hole.
The traffic light at the entrance is set to red.
Turn on the cross-hole indicator of the pedestrian in the fire to indicate the direction of the person's escape.
The fire tunnel opening and the inside of the cave show fire and safety evacuation information according to the upstream and downstream positions of the fire point. At the same time, the monitoring personnel use the tunnel broadcast in the sub-center to conduct command, dispatch and guide the scene.
After the rescue department arrives at the scene in the rescue phase, the following rescue phase plan is implemented.
The inside and outside of the fire tunnel hole is set as: "Tunnel fire, no traffic", the traffic light cross-hole indicator is turned on: the traffic light is set to the front red cross:
After setting the two-way traffic guidance sign, the inside and outside of the tunnel in the side tunnel is set to "two-way driving, no overtaking", the over-lane tunnel lights are changed to the opposite direction, and the traffic lights are set to yellow.
Turn on all the fans, and the direction of the exhaust is in the direction of the tunnel traffic: For the special tunnels with vertical fans, the plan should be made after the on-site simulation investigation.
In the fire extinguishing phase, all the fans are turned on to increase the air volume to facilitate fire extinguishing and cooling. After the fire extinguishing, the fan should be gradually closed by the monitoring sub-center or through the on-site control panel to confirm that the normal operation can be resumed after the normal operation.
Due to the complexity of the actual situation, the situation is often different each time you encounter a fire or other accident. The response speed of traffic management personnel and firefighters, and the severity of each incident are not exactly the same. Therefore, the division and transition of the above three stages must be determined by the on-duty personnel in combination with the actual situation. The control schemes of each stage should still be artificial. The operation is completed under the supervision conditions.
In case of failure and maintenance, the accident plan equipment should have a set of control plans. The system generally provides a manual solution, and the on-duty personnel combine various information to select a specific solution to execute. In the system menu of the control computer, there are a series of different control schemes for different tunnels, which are combined with lane lights, traffic lights, lighting and fans. The duty officer can choose a set of control schemes to deliver traffic control.
The implementation of the above traffic monitoring program is only a basic framework content. All the complete implementation modes must be fully simulated and explored in practice, and the feasible solutions are listed in the computer for the call. In addition, all control schemes should have manual/automatic, on-site/remote mode, and on-site control is preferred.
In order to achieve the above objectives, there must be an open and reliable hardware support technology solution. In addition to collecting and controlling road information, the solution should be combined with tunnel ventilation and lighting design to form a solution for traffic monitoring and power monitoring. For the power supply practice of tunnel medium voltage power supply in our province, the hardware networking design can be carried out according to the following ideas: power and traffic data acquisition shared data acquisition and control unit, which is located in the tunnel distribution room on the left side of the tunnel. In addition to collecting power monitoring equipment, CO/VI, wind speed and direction indicator, and light intensity detector should be collected to control the crosswalk lights and lane control lights of the pedestrian walkway, and add a love board in the cave; CO/VI, wind speed and direction meter, light The detector is installed on the left side of the tunnel. The vehicle detector and the controller are installed on the right side of the tunnel. The Ethernet ports of the RJ451O/1OOM are respectively uploaded to the hole through the optical transceiver, and then uploaded to the center through the Ethernet switch. . To ensure the data transfer rate.
Conclusion Traffic monitoring system is a basic work to realize intelligent transportation in the future. After realizing the complete traffic monitoring requirements in local road sections, the information sharing of the whole road network and the seamless connection of information should be realized step by step. The traffic conditions, combined with the traffic conditions of adjacent road sections, develop their own control plans to ensure safe and smooth traffic on the expressway. In order to achieve this goal, consider selecting a powerful monitoring system integrator, working with experienced owners to make a unified and complete plan, continuously summarizing, modifying and perfecting various monitoring programs to achieve the best traffic. Monitor the effect.
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