Shoe track smoothness test and shoe track video monitoring system
Release time: 22-11-09 17:15 Number of views: sixty-one
The power supply voltage of urban rail transit usually adopts DC1500V or DC750V, and the main power receiving modes of its vehicles are divided into overhead catenary current collection and the third rail current collection. The third rail current collection can be divided into three modes: upper current collection, lower current collection and side current collection according to the relative position of current collection shoe and supply rail. Shanghai Rail Transit Pujiang Line is an automatic passenger transport (APM) system with intermediate guide rubber tyred track. It uses the side current collection of the third rail (DC ± 375V). The current collection on the grounding rail is used as the grounding, which is quite different from the traditional three rail current collection. Therefore, it is necessary to conduct in-depth research on the boot rail relationship of the APM system on the Pujiang Line to ensure reliable current collection and normal train operation.
This article adopts Data acquisition equipment of Dewei Chuang Test the smoothness of the shoe rail of the line, analyze the collected data and check the actual site, predict the potential safety hazards and rectify them in time. At the same time, through the research and application of the shoe rail monitoring system, the shoe rail conflict events are located and timely overhauled, providing technical support and guarantee for the daily operation and maintenance of the line.
1 Analysis of the characteristics of the boot rail relationship of the APM system on the Pujiang Line
The APM system of Shanghai Rail Transit Pujiang Line is different from the traditional urban rail transit lines. It uses rubber tires and sets a guide rail in the middle for guiding operation. Two C-shaped steel aluminum composite rails and one ground rail are erected on the guide rail through insulating supports. The power supply voltage is DC ± 375v. The sectional drawing of the power rail and ground rail is shown in Figure 1. The APM system of Pujiang Line operates in a fully automatic driverless mode. Each bogie is equipped with two collector shoes and one grounding shoe. The collector shoes take power in the DC ± 375V power supply rail slot for operation, and the grounding shoes are safely grounded through the grounding rail. The power supply rail and ground rail are not continuous, and there are insulation joints, expansion joints and disconnects at the turnout position. The installation deviation maintenance at any place is not in place, which may lead to the irregularity of the collector shoe and ground shoe when passing through. In serious cases, the collector shoe may even slip out of the power supply rail, causing damage to the insulation cover of the power supply rail, leading to single-stage grounding fault. Therefore, it is necessary to study an effective test and detection method to detect whether the installation accuracy of power supply rail and grounding rail is up to standard, whether the collector shoe and grounding shoe run smoothly, whether the maintenance of power supply rail and grounding rail is in place, and whether the collector shoe and grounding shoe run smoothly before the system is put into use. In the shoe rail smoothness test in this paper, the vibration acceleration sensor is used to collect the vibration acceleration of the collector shoe and the grounding shoe, judge whether the collector shoe and the grounding shoe are running smoothly through their vibration acceleration values, and determine the position of the irregularity through the positioning system.
2 Test and research on the smoothness of shoe rail
2.1 Test overview
1) The test content is the ride comfort of the APM system of Shanghai Rail Transit Pujiang Line. 2) The test section is from Shen Du Highway Station to Huizhen Road Station. 3) The test vehicle is 4-car marshalling vehicle of Pujiang Line, which adopts no-load mode. The carbon brush wear of collector shoe and grounding shoe is less than 10%, and the static contact pressure is ≥ 45N. 4) Two collector shoes and one grounding shoe of one bogie of APM vehicle are respectively installed with triaxial acceleration sensors as test points, and a global positioning system (GPS) is installed on the roof. 5) Under the test condition, the train shall be driven according to the normal train diagram, and three round trips shall be conducted in the full automatic driverless mode between Shendu Highway Station and Huizhen Road Station. 6) Test equipment includes DEWE3-A4 Data Acquisition Instrument , three-axis acceleration sensor, global positioning system, a laptop computer, and several wires. The test equipment architecture is shown in Figure 2.
2.2 Test process
This test is mainly carried out on APM train vehicles. Two collector shoes and one grounding shoe of its bogie are respectively installed with triaxial acceleration sensors. The test process is as follows: 1) Check and confirm that the carbon brush wear of the selected collector shoe and grounding shoe is less than 10%, and the static contact pressure is ≥ 45N. 2) Fix the three-axis acceleration sensor on two collector shoes and one grounding shoe respectively. 3) Fix the GPS antenna on the roof in the correct direction. 4) Connect 9 connectors of 3 triaxial acceleration sensors and 10 GPS connectors of Dewetron data acquisition Channel. 6) Commissioning Dewetron Data acquisition software. 7) Conduct data pre collection after debugging; After pre acquisition, carry out three round trips on the main line to collect the acceleration test data and GPS position data of each axis of three triaxial acceleration sensors respectively.
2.3 Data analysis and evaluation
The data measured in the test are the real-time acceleration values of the whole main line in x, y and z directions of three acceleration sensors on two collector shoes and one grounding shoe. By analyzing the acceleration curve, it is found that the vibration acceleration of the collector shoe is mainly in the horizontal direction, and the vibration acceleration of the grounding shoe is mainly in the vertical direction. Through on-site inspection, it is found that the main reasons for the horizontal vibration peak of the collector shoe are: ① Alignment does not meet the requirements; ② The insulation joint is severely worn. After adjusting the horizontal alignment of the power rail and replacing the excessively worn insulating joint, the horizontal vibration peak value of the collector shoe is significantly reduced. The comparison data of vibration acceleration before and after power rail adjustment is shown in Figure 3.
The main reason for the vertical vibration peak of the grounding shoe is that the alignment of the grounding rail in the vertical direction does not meet the requirements. By adjusting the alignment of the grounding rail in the vertical direction, the vibration peak of the grounding shoe in the vertical direction is significantly reduced. The comparison data of vibration acceleration before and after adjustment is shown in Figure 4.
3 Function, composition and principle of shoe rail video monitoring system
3.1 System functions
The on-board shoe rail video monitoring system adopts non-contact current sensor Monitoring mode, which can realize real-time monitoring of traction current. The system can judge whether there is abnormal shoe rail by monitoring the change of traction current. In case of abnormal conditions, the analysis server of the system will send signals to the video monitoring system, which will collect videos and images and send alarm information, videos and images to the operation control center through the train ground wireless transmission channel. The workflow of the shoe rail monitoring system is shown in Figure 5. The dispatcher of the operation control center confirms the fault information and image by viewing the alarm information and image pushed from the monitoring screen; Arrange on-site emergency disposal personnel according to the severity of the fault, and implement emergency disposal according to the corresponding process.
3.2 System composition
The boot rail video monitoring system is mainly composed of video acquisition under the train, current sensor and transmission equipment, power module in the train, switch, analysis server and video acquisition server, ground center server, etc. All data collected from the video acquisition module under the vehicle are transmitted to the switches in each vehicle through the network cable. The switch communicates with the on-board master server, which stores, analyzes and processes the data, and communicates with the server in the control center through the vehicle ground wireless network.
3.3 Logic judgment principle of shoe rail abnormality
The key to the logic judgment of shoe rail monitoring is that the judgment and alarm must be made accurately when the collector shoe is abnormal, and the abnormal alarm cannot be judged due to the imbalance surface of positive and negative collector shoe current when the shoe rail is not abnormal. Therefore, in the logic calculation, judge and calculate whether the logic threshold value of the design current of the vehicle auxiliary load is higher than the load current value; In addition, the logic judgment results made in the non static or coasting conditions of the vehicle are more accurate and can reduce false alarms. The logic judgment of the design based on this principle shall include: 1) An alarm is given when the positive or negative polarity of a single collector shoe of a single vehicle is taken off. It is applicable to current monitoring of all collector shoes. If the total current value of the positive or negative collector shoe is more than 55A, and the current value of one of the collector shoes is monitored to be less than 1A, and the duration is more than 5s, the abnormal collector shoe will give an alarm. 2) One side collector shoe with positive or negative polarity of a single vehicle releases the shoe alarm. Compare the total current of collector shoes between four vehicles. If the average current of a vehicle is below 1A, and the total positive or negative current of all collector shoes of other vehicles is more than 50A, and the duration is more than 5s, all collector shoes of the corresponding single vehicle will give an alarm when they take off. 3) One side collector shoe with positive or negative polarity of a single section of vehicle is grounded when the shoe is taken off. The current value of collector shoe of each vehicle is monitored in real time. If the system detects that the current value of a single collector shoe is above 600A, it will immediately take off the shoe and give an alarm; If it is detected that the sum of positive and negative current values is different, and the difference between the two sums is more than 50A, it can be judged that there is a collector shoe grounding problem in the polarity where the sum is relatively large. If the current value of two collector shoes with the same polarity is smaller, the collector shoe will fall off and be grounded, and the alarm mechanism will be started. 4) The first case of current collection instability alarm when the positive or negative side collector shoe of a single vehicle is taken off. It is applicable to current monitoring of all collector shoes. If the total current value of the positive or negative collector shoe is more than 50A, and the current value of any collector shoe is monitored to be less than 1A, and the cumulative duration within 1min is more than 5s, the abnormal collector shoe will give an abnormal early warning type alarm. 5) The second condition of the current collection instability alarm when the positive or negative side collector shoe of a single vehicle is taken off. If the current value on one side drops rapidly, and the derivative of the current value is close to infinity (differential treatment of current value), that is, the current value drops rapidly, then it can be judged that the collector shoe is at risk of falling off, and an early warning of shoe removal should be given. 6) The third condition of the current collection instability alarm when the positive or negative side collector shoe of a single vehicle is taken off. Analyze the data dispersion degree of different collector shoes in the vehicle, obtain the difference, analyze based on the difference, and give an early warning of shoe removal according to the discrete difference of more than 20%.
3.4 Test verification
According to the above logic judgment principle of shoe rail abnormality, the related logic judgment was verified by laboratory test and real vehicle test. Due to space limitation, this paper only gives the current data of a single collector shoe during the actual vehicle test. The four collector shoes in a single vehicle are numbered as No. 1, No. 2, No. 3 and No. 4 collector shoes respectively. During the operation of the train, the No. 3 collector shoe is separated from the power rail through the insulating transmission device, which meets the first logical judgment above: the total current value of the positive and negative collector shoe is more than 55A, the current value of the No. 3 collector shoe is less than 1A, and the duration is more than 5s. The current curve of the collector shoe is shown in Figure 6, so the monitoring system triggers the alarm of No. 3 collector shoe falling off, And push the alarm information and image value to the control center.
4 Conclusion
The results obtained from the test of shoe rail smoothness in this paper are: in the continuous power rail and ground rail sections, the shoe rail smoothness index is good; At the turnout section, the smoothness of the boot rail is greatly affected by the alignment accuracy of the power rail and ground rail. Through regular shoe rail smoothness test, a large number of test data are analyzed, and the peak vibration acceleration data are counted for preventive maintenance, which can greatly reduce the occurrence of shoe rail conflict events. Through the research of the boot rail video monitoring system, this paper realizes the real-time monitoring of the boot rail status of the unmanned APM system train. The monitoring system can automatically identify and monitor the abnormal phenomenon of most of the shoe rail operation. It can use the train ground wireless communication network to push fault alarm information, fault video and images to the control center, and then the control center will centrally control all trains. The shoe rail smoothness test provides a basis for preventive maintenance. Combined with the application of the shoe rail video monitoring system in the operation process, it can greatly improve the efficiency of APM system's shoe rail operation safety monitoring and management and maintenance.
