CN101633363A - Train curve prewarning system and prewarning method of wireless sensor network - Google Patents

Abstract

The invention provides a train curve early warning system of a wireless sensor network and its early warning method, mainly composed of a MEMS accelerometer module, a data acquisition module, a GPS positioning system, a wireless transceiver module, a danger alarm module and a display module. The centripetal acceleration of the train detected by the wireless sensor node through the MEMS micro-accelerometer is compared with the acceleration threshold at the track curve. When the measured acceleration is greater than the warning value or the initial value of the system, the lateral acceleration value is sent to the wireless The sensor convergence node, the convergence node adopts the form of sound and light alarm to remind the train driver to slow down, and at the same time, the current geographical location of the train, the maximum lateral acceleration value and the limit speed of the train at the curve are displayed on the LCD through the display module. On the display module, prevent the train from rolling over due to overspeed. The system is small in size and high in reliability, can be applied to ordinary trains or bullet trains, and has a significant effect on improving the running safety of trains.

Description

Train curve warning system and its warning method based on wireless sensor network

(1) Technical field

The invention relates to a safety monitoring and alarm system, in particular to a train curve early warning system.

(2) Background technology

With the continuous development of science and technology and the gradual acceleration of the pace of society, people have put forward higher requirements for the speed of transportation. However, for the train as a means of transportation, the reliability and stability of the train has always been trusted by the public, but once a train accident occurs, it will bring huge losses to the society. In recent years, due to the continuous speeding up of railways, more and more problems that did not appear before the speeding up have been manifested, causing huge losses to the lives of the people and the property of the country. For example, on April 28, 2008, Beijing The T195 train bound for Qingdao derailed due to the high speed at the bend near Zhoucun and collided with another train, killing 72 people and injuring 416. At about 2:00 am on March 9, 2008, an internal combustion engine head of a moving train derailed and overturned on the Xian (Yang) Tong (Chuan) Line on the north side of Chaoyang 1st Road in Xianyang City, causing a five-six accident near the railway. The meter-long courtyard wall was destroyed. How to avoid the rollover problem (also known as dragon-drawing) of the train in the running process has become the primary issue to be considered to ensure the safety of the train. There are two main reasons for the rollover of the train. One is objectively the rollover caused by the track being in disrepair for a long time and the rails are aging. Big induced rollover. The current rollover research is still based on the theoretical stage of laboratory research, and many models have been established to analyze the conditions of train rollover. However, the automatic warning system for leaving the curve is not mature.

(3) Contents of the invention

The purpose of the present invention is to provide a wireless sensor network train curve early warning system and its early warning method that can realize the alarm of the rollover phenomenon when the train is turning at high speed and avoid the rollover accident.

The purpose of the present invention is achieved like this: the train curve warning system of this wireless sensor network mainly is made up of wireless sensor converging node and wireless sensor node, and wireless sensor converging node is made up of microprocessor module, RF radio frequency transceiver module, MEMS acceleration sensor, GPS module, inclinometer circuit, alarm circuit, LED display, LCD display and power supply system, RF radio frequency transceiver module, MEMS acceleration sensor, GPS module, inclination angle circuit, alarm circuit, LED display, LCD display and power system are all connected to the micro The processor module, the wireless sensor node is composed of a microprocessor module, a wireless transceiver module, an inclinometer module, an accelerometer module, a GPS module and a power module, and the wireless transceiver module, an inclination module, an accelerometer module, a GPS module and a power module are all Connected with the microprocessor module, the MEMS acceleration sensor and the accelerometer module are installed in the train carriage.

The early warning method of the present invention is: the system adopts ARM as the core microprocessor, adopts MEMS micro-mechanical acceleration sensor and GPS positioning system as the core information acquisition module, wherein the inclination measurement circuit measures by using a three-axis accelerometer, and the accelerometer is installed In the train compartment, the measured centripetal acceleration and alarm information are sent to the locomotive’s wireless sensor main control convergence node through the wireless sensor network, and the GPS positioning system transmits the information of the driving section to the ARM microprocessor through satellite positioning, through The measured inclination angle is combined with the data of the car body to obtain the centripetal acceleration a1 of the train in this road section. At the same time, the road section information determined by GPS will also give a maximum centripetal acceleration a2. If the measured centripetal acceleration is greater than a1 or a2 Either of these, the train is at risk of rollover.

Technical characteristics of the present invention have:

1. The system is composed of a wireless sensor convergence node and a wireless sensor node. The wireless sensor node uses an accelerometer to collect the lateral acceleration of the train in real time, and compares it with the threshold acceleration at the curve. When there is danger, the acceleration information and the alarm The information is sent to the wireless sensor convergence node through the radio frequency transceiver circuit, and the convergence node uses sound and light to alarm.

2. The wireless sensor node is mainly composed of a microprocessor, a GPS module, an accelerometer module and a wireless radio frequency transceiver module. The output terminal of the accelerometer module is connected with the input terminal of the microprocessor, the GPS module is connected with the microprocessor by serial communication, and the wireless transceiver module and the microprocessor communicate by SPI or serial.

3. The wireless sensor convergence node is composed of a microprocessor, a radio frequency transceiver module, a GPS module, an LCD display, a power supply module, an alarm module, an LED driver display module and a keyboard module. The microprocessor and the GPS module use the serial port to communicate; the wireless transceiver module and the microprocessor use the SPI or serial port to communicate; the input terminal of the LCD display is connected to the microprocessor; the alarm module uses a high-brightness light-emitting diode and a buzzer to communicate Audible alarm.

4. The train curve safety monitoring and alarm system also includes a roll angle circuit, which is characterized in that it can be a MEMS high-precision micromachined three-axis accelerometer or a plurality of low-precision accelerometers used in conjunction Measuring angle information can also be a gyroscope and a dedicated side angle circuit, the output port of which is connected to the I/O input port of the microprocessor.

5. The train curve safety monitoring and alarm system also includes a GPS module for locating the geographic coordinates of the train, and setting the threshold reasonably in combination with the maximum centripetal acceleration of the road section stored in the database. The inclination angle of the track can also be measured by the side angle circuit installed in the wireless sensor node, and the rollover threshold calculated according to the force analysis of the train can also be determined by the common information of the two. This has just guaranteed the safety of train running to the greatest extent.

6. The MEMS micromachined accelerometer is one or more accelerometers with single axis, double axis, and three axes. The output of the acceleration is an analog signal or a digital signal. If the output is an analog signal, it will be converted by A/D and The input port of the microprocessor is connected, and the accelerometer of the digital interface is directly connected with the input port of the microprocessor.

7. The train curve safety monitoring and alarm system also includes an alarm circuit. The alarm circuit is mainly composed of a high-brightness light-emitting diode and a buzzer or a voice circuit, and its driving circuit adopts a constant current integrated circuit or a discrete circuit. Its output is respectively connected with the input of the microprocessor. The system is designed as a three-level alarm system. When the detected acceleration value is close to the set acceleration threshold, the three-level alarm system responds in turn. The first two levels are indicated by light-emitting diodes. When the detected acceleration value exceeds the safety threshold , the buzzer responds to complete the alarm of the entire system.

8. The described train curve safety detection and alarm system uses a radio frequency transceiver module, the RF radio frequency transceiver module and the wireless transceiver module are connected to a power amplifier module, and the power amplifier module is connected to an antenna; the radio frequency transceiver module adopts a power amplifier circuit , to ensure the strength of the received signal and improve the anti-interference performance of the system. The acceleration information and alarm information collected by the sensor are sent to the wireless sensor convergence node by the radio frequency transceiver module through power amplification.

9. The train curve safety detection and alarm system also includes a keyboard input module and an LCD display module. The keyboard can be used to input relevant information of the train, such as: load capacity and self-weight information, and the height of the center of gravity of the vehicle after loading can be changed. A good set of safety thresholds can also be used for self-testing of the system. The use of the LCD module enhances the function of human-computer interaction, and they are respectively connected with the input ports of the microprocessor.

In order to solve the technical problem that the train is prone to rollover when turning at high speed, the basic idea of the technical solution adopted by the present invention is to use the wireless sensor network as the technical platform, and use the biaxial acceleration to detect the lateral acceleration value during the train running in real time . The three-axis acceleration is used to detect the track inclination at the curve, and the local processor processes it, and analyzes the data through the established mathematical model of the train curve to obtain the actual lateral acceleration threshold. At the same time, the geographical coordinate information of the track curve and the theoretical maximum lateral acceleration information list of the curve are stored in the system, and the GPS positioning system installed in each carriage is used to detect the geographical location information of the train in real time, and the information is obtained by looking up the table. The theoretical maximum acceleration value at the curve is compared with the acceleration information calculated in the mathematical model at the curve and the theoretical maximum acceleration information. When the curve is reached, the minimum value of the two thresholds is selected as the reference value. When the train’s When the lateral acceleration exceeds the minimum threshold, the danger information is sent to the main control node of the locomotive through the wireless sensor network, and the driver is reminded to slow down in the form of sound and light to prevent the train from turning over on the curve. The present invention simultaneously considers the measured maximum acceleration during the running of the train and the theoretical maximum acceleration of the train at a specific track curve, and uses the information fusion of the two as the condition for evaluating the rollover of the train, compared with the traditional single condition as the judgment basis, with higher reliability.

When the train is moving, it is only subjected to two forces: the vertical gravity and the support force of the rails on the train. On the vertical plane, the component force of the support force and the gravity cancel each other out, while the horizontal component force of the support force provides the centripetal force required for the train to turn. Because there is no seamless connection between the rails, this makes the train produce a change in the force of the vertical rail and the rail; at the same time, the front and rear carriages have a pulling force on the train. In model analysis, because this force changes periodically and has little influence on the whole, a low-pass filter can be used to filter it out.

Calculate the maximum centripetal acceleration using the rotational equilibrium of the object. The moment passing through the fulcrum of rotation will not affect the rotational balance of the object. Considering the limit situation that the train is about to overturn: It can be seen from Fig. 2 that the train turns to the left, at this time the wheels on the left side of the train will lose contact with the rails, so all the supporting force will be provided by the rails on the right side, and because the train will The junction between the right rail and the train is used as the fulcrum, so the moment generated by the supporting force will not affect the rotational balance of the train. It can be seen from the force analysis that the torque produced by the gravity in the process of train rotation is the moment of centrifugal force.

g·cos∠3＝a·sin∠3

Among them, mg is the mass of the train, L is the distance between two rails, h is the height of the center of gravity of the train, and F′ is the centrifugal force of the train. Simplifying the formula further, we can get:

a＝g·cot∠3

Wherein, a is the maximum centripetal acceleration a ₁ that the train can withstand. Meanwhile, the maximum threshold acceleration provided by GPS positioning is a2. When the actual measured acceleration value is greater than any one of the above two values, the system can give an alarm in the form of buzzer or light to notify the driver to take corresponding emergency measures. The system takes into account the measured maximum acceleration and the theoretical maximum acceleration provided by the system database at the same time, and uses the information fusion of the two as the condition for evaluating the train rollover. Compared with the traditional single condition as the judgment basis, it has more advantages. high reliability.

The invention relates to a train curve safety monitoring and alarm system. The system is mainly in the field of railway traffic, and mainly completes the functions of speed limit on curves and alarm prompts during the high-speed running of trains, and can effectively avoid the occurrence of train rollover. Improving the safety of rail transport.

The invention is a safety monitoring system for a train curve, which aims at alarming before the train rollover danger occurs when the train is turning at high speed, and reminds the driver to take corresponding measures to prevent the train from rolling over. The system mainly adopts the wireless sensor network technology to realize the safety warning of the system. The system is mainly composed of MEMS accelerometer module, data acquisition module, GPS positioning system, wireless transceiver module, danger alarm module and display module. The centripetal acceleration of the train detected by the wireless sensor node through the MEMS micro-accelerometer is compared with the acceleration threshold at the track curve. The lateral acceleration value is sent to the wireless sensor convergence node. The convergence node adopts the form of sound and light alarm to remind the train driver to slow down. The limit speed of the train is displayed on the liquid crystal display module to prevent the train from rolling over due to overspeed. The system of the invention has small volume and high reliability, can be applied to ordinary trains or bullet trains, and has a significant effect on improving the running safety of trains.

(4) Description of drawings

Fig. 1 is the hardware composition block diagram of system of the present invention;

Fig. 2 is the stress analysis figure of train curve place;

Fig. 3 is the interface circuit diagram of the radio frequency module;

Fig. 4 is the schematic diagram of the RF transceiver module circuit;

Figure 5 is a schematic diagram of the system power supply;

Fig. 6 is a schematic diagram of the system reset circuit;

Fig. 7 is a schematic diagram of the acceleration acquisition circuit;

Figure 8 is a schematic diagram of the LCD circuit;

Fig. 9 is a schematic diagram of an LED circuit;

Fig. 10 is a schematic diagram of the GPS interface circuit;

Figure 11 is a schematic diagram of the buzzer circuit;

Fig. 12 is a circuit schematic diagram of an alarm indicator light;

Fig. 13 is a schematic diagram of the keyboard circuit;

Fig. 14 is a flow chart of the system lower computer software.

(5) Specific implementation methods

The present invention will be further described below in conjunction with accompanying drawing and specific embodiment:

In conjunction with Fig. 1, the train curve early warning system of the wireless sensor network of the present embodiment is mainly composed of a wireless sensor convergence node and a wireless sensor node, and the wireless sensor convergence node is composed of a microprocessor module, an RF radio frequency transceiver module, a MEMS acceleration sensor, a GPS module, Composed of inclinometer circuit, alarm circuit, LED display, LCD display and power supply system, RF radio frequency transceiver module, MEMS acceleration sensor, GPS module, inclination angle circuit, alarm circuit, LED display, LCD display and power system are all connected to the microprocessor module , the wireless sensor node is composed of a microprocessor module, a wireless transceiver module, an inclinometer module, an accelerometer module, a GPS module and a power module, and the wireless transceiver module, an inclination module, an accelerometer module, a GPS module and a power module are connected Sensor module, MEMS acceleration sensor and accelerometer module are installed in the train carriage.

5, the entire hardware circuit system of this embodiment uses LM7805 or LM2575 three-terminal voltage regulator to obtain 5V working voltage and SPX1117-3.3 or LP2950CZ-3.3 three-terminal voltage regulator to obtain 3.3V working voltage. The system uses MAX708SCSA or CAT1025JI-30 reset chip to output reset signal to the system, as shown in Figure 6. Design the JTAG interface in the data acquisition circuit and the main processor module, so as to program the processor online according to actual needs.

Combined with the block diagram on the right side of Figure 1, the accelerometer and data acquisition module are shown. This module uses ARM7LPC213X as the microprocessor. The schematic diagram of the axial accelerometer and its I2C drive circuit is shown in Figure 7. The I2C drive is realized by two pieces of Philips P82B96, and the accelerometer module is connected to the I2C1 port of LPC213X-P0.11 (SCL) and P0.14 (SDA ). As shown in the figure, the microprocessor completes the data transmission by reading and writing the corresponding registers of the accelerometer MXC62020M, and improves the measurement accuracy of the system through offset compensation and corresponding digital filtering. The microprocessor sends the collected data to the RF radio frequency module through the serial port-P0.0 (TX) and P0.1 (RX), as shown in Figure 4, the RF transceiver module sends the data back to the main processor module for processing . In this module, four LED lights - LED2, LED3, LED4, LED5 are respectively used to indicate the working status of the RF transceiver module. This module contains a GPS module, which is used to collect the specific orientation of the train carriage, and at the same time, the collected data is sent back to the main processor through the RF module.

The block diagram on the left side of Figure 1 shows the main processor module, which uses LPC213X as the processor, and its hardware circuit is mainly composed of Figures 4-5 and Figures 7-13. This module provides the interface of the RF transceiver module and four independent LED lights indicating the working status of the RF front-end. The system is also designed with a standard RS232 serial port to connect to the GPS module, and at the same time display the specific direction of the train in real time through the LCD. The circuit structure is shown in Figure 8. The LED digital tube provides an intuitive digital output, which is mainly used to display the data input of the keyboard. The circuit diagram is shown in Figure 9. The LED driver adopts 74LS245 to drive four static common anode LED digital tubes, and CS1, CS2, CS3, CS4 are respectively used as the chip selection terminals of the four digital tubes. The six independent LED lights in the system - DS1, DS2, DS3, DS4, DS5, and DS6 are connected by common anode. When the corresponding I/O port of the connected LPC213X outputs a low level, the LED lights are turned on. On, when the output is high level, the LED light is off, as shown in Figure 12, the circuit uses the driving mode of I/O port sink current to drive the LED, which ensures the display brightness of the LED. The LED array consists of a group of high brightness or super Composed of high-brightness, single-color or double-primary-color or three-primary-color light-emitting diodes, placed side by side in columns. According to the rolling degree of the train, the light-emitting diodes are lighted in sequence, and the more light-emitting diodes are lighted, the more serious the rolling degree of the vehicle is. When the vehicle roll is at the warning threshold (70% of the acceleration threshold), two of the LEDs start to flash. When the detected acceleration value continues to increase, correspondingly, the remaining LED lights also start to flash. If the acceleration value exceeds the acceleration threshold 90% of the time, the buzzer will give an alarm. In this way, the driver and passengers can be informed of the safety of the train at the first time. The buzzer control circuit uses PNP transistor Q1 for drive control. The schematic diagram of the circuit structure is shown in Figure 11. When the P0.14 control level outputs "0", Q1 is turned on and the buzzer buzzes; when P0.7 When the control level outputs "1", Q1 is cut off and the buzzer stops beeping. This system uses a 4X4 matrix keyboard, its row lines are R1, R2, R3, R4, which are respectively connected to P0.26, P1.18, P1.19, P0.22 of LPC213X, and its column lines are L1, L2, L3 and L4 are respectively connected to P0.15, P0.16, P1.20, and P0.19 of LPC213X, and the row line is used as the input of the key. The circuit structure is shown in Figure 13. Since the I/O port has no internal pull-up resistor when it is used as an input terminal, the pull-up resistor of R5-R8 is used externally. The key recognition adopts the scanning method to detect the low-level input of the I/O port, and all I/O ports use the GPIO function. The functions of the buttons are divided as follows:

Number keys from 1.0 to 9;

2. Input the decimal point ".";

3. Keyboard start START;

4. Digital reset key CLEAR;

5. System self-test CHECK.

The flow chart of the entire system program is shown in Figure 14. When the system is installed for the first time, the user needs to input the relevant parameters of the train, such as unloaded mass, load, height of the center of gravity, etc., according to the established mathematical model, the program will calculate the parameters related to the acceleration threshold, combined with the train running process The collected relevant data can be used to calculate the safety threshold of acceleration. The sensor collects the lateral acceleration and inclination information of the train in real time, and converts it into the comprehensive rollover factor of the train as the condition for judging the rollover of the train. When the rollover factor reaches the threshold of the train rollover, an alarm is issued, so that it can Avoiding the occurrence of rollover can effectively reduce traffic accidents caused by rollover. Since a variety of functional modules GPS and MEMS accelerometers are used in the system, time-division multiplexing must be done when programming the processor, so as to ensure the normal progress of data transmission.

Claims (10)

1, a kind of train curve forewarn system of wireless sensor network, the train curve forewarn system that it is characterized in that this wireless sensor network mainly is made up of wireless senser aggregation node and wireless sensor node, the wireless senser aggregation node is by microprocessor module, the RF RF receiving and transmission module, the MEMS acceleration pick-up, the GPS module, survey the inclination angle circuit, warning circuit, LED shows, LCD shows and power-supply system is formed, the RF RF receiving and transmission module, the MEMS acceleration pick-up, the GPS module, survey the inclination angle circuit, warning circuit, LED shows, the LCD demonstration all is connected microprocessor module with power-supply system, wireless sensor node is by microprocessor module, radio receiving transmitting module, survey the inclination angle module, the accelerometer module, GPS module and power module are formed, radio receiving transmitting module, survey the inclination angle module, the accelerometer module, the GPS module all is connected microprocessor module with power module, and MEMS acceleration pick-up and accelerometer module are loaded in the railway car.

2, the train curve forewarn system of wireless sensor network according to claim 1, the mouth that it is characterized in that the accelerometer module of described wireless sensor node links to each other with the input end of microprocessor module, the GPS module adopts the mode of serial communication to link to each other with microprocessor module, and radio receiving transmitting module and microprocessor module adopt SPI mode or serial mode to communicate.

3, the train curve forewarn system of wireless sensor network according to claim 1 is characterized in that the microprocessor module of described wireless senser aggregation node and GPS module adopt serial ports to communicate; RF RF receiving and transmission module and microprocessor module adopt SPI or serial ports to communicate; The input end that LCD shows links to each other with microprocessor module; Alarm module adopts the light-emitting diode and the buzzer phone of high brightness to carry out sound and light alarm.

4, according to the train curve forewarn system of the wireless sensor network of claim 1, it is characterized in that described angle of roll circuit is that the accelerometer of the high-precision micromechanics triaxial accelerometer of MEMS or a plurality of low precision is united the information that takes measurement of an angle of using, also can be gyroscope and special-purpose side angle circuit, its output port links to each other with the I/O input port of microprocessor module.

5, according to the train curve forewarn system of claim 1,4 described wireless sensor networks, it is characterized in that described GPS module is used for locating the geographic coordinates of train driving, and the maximum centripetal acceleration of storing in the binding data storehouse that this highway section allowed, leaning angle that threshold value can go out track by the side angle circuit measuring that is installed in wireless sensor node is set according to the rollover threshold value that the Calculation and Analysis of Force of train goes out, also can determines by the common information of the two.

6, the train curve forewarn system of wireless sensor network according to claim 1, it is characterized in that described MEMS micro-mechanical accelerometer is single shaft, twin shaft, one or more accelerometers of three, acceleration/accel is output as analog signal or digital signal, output is if analog signal, link to each other with the input port of microprocessor by A/D conversion back, the accelerometer of digital interface directly links to each other with the input interface of microprocessor module.

7, the train curve forewarn system of wireless sensor network according to claim 1, it is characterized in that described warning circuit is made up of the light-emitting diode of high brightness and buzzer phone or sound circuit, its driving circuit adopts the integrated circuit or the discrete circuitry of constant current, its output is connected with the input of microprocessor respectively, this system is three grades of warnings, when detected accekeration during near the acceleration rate threshold set, three grades of warnings are made response successively, preceding two-stage is indicated by light-emitting diode, when detected accekeration surpasses secure threshold, buzzer phone is made response, finishes the warning of total system with this.

8, the train curve forewarn system of wireless sensor network according to claim 1, it is characterized in that RF receiving and transmission module has adopted power amplification circuit, the acceleration information of sensor acquisition and alarm message send to the wireless senser aggregation node by RF receiving and transmission module through power gain.

9, the train curve forewarn system of wireless sensor network according to claim 1 is characterized in that the keyboard load module is connected with the input port of microprocessor module respectively with the LCD display module.

10, a kind of method for early warning of train curve forewarn system of wireless sensor network, it is characterized in that system is made up of wireless senser aggregation node and wireless sensor node, adopt the microprocessor of ARM as core, adopt MEMS micro-machine acceleration transducer and GPS position fixing system as the core information acquisition module, wherein the measurement of dip angle circuit is measured by using triaxial accelerometer, degree of will speed up meter is loaded in the railway car, adopt the lateral acceleration of the real-time collection train of acceleration pick-up, send to the centripetal acceleration and the alarm message that record in the wireless senser master control aggregation node of locomotive by wireless sensor network, the GPS position fixing system is located via satellite running section information is reached the ARM microprocessor simultaneously, draw train at this highway section centripetal acceleration a1 by the inclination angle that recorded and in conjunction with the data of car body, the road section information of being determined by GPS also can provide a maximum centripetal acceleration a2 simultaneously, if the centripetal acceleration of actual measurement is greater than among a1 or the a2 any, just there is the danger that rollover takes place in train, when dangerous, degree of will speed up information and alarm message send to the wireless senser aggregation node by RF transmit-receive circuit, and aggregation node adopts the form of acousto-optic to report to the police.

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