CN201402217Y - Bridge load detection device based on wireless sensor network - Google Patents

Abstract

The utility model discloses a bridge load detection device based on wireless sensor network, the device comprises collection module, amount of deflection collection module, acceleration collection module, data processing module, wireless transceiver module, collection module's that meets an emergency power module and seven modules of data processing and wireless transceiver module's power module, has sensor data acquisition, handles, wireless transmission and sensor node's control management and data acquisition's host computer show, functions such as analysis and evaluation. The method can comprehensively detect and comprehensively evaluate the performance of the bridge with various structures widely used at present, is used for detecting the construction quality of a newly-built bridge, evaluating the bearing capacity of the existing bridge and verifying and developing the structural design of the bridge.

Description

A bridge load detection device based on wireless sensor network

technical field

The utility model relates to a bridge load detection device, in particular to a bridge load detection device based on a wireless sensor network.

Background technique

In the current bridge load detection, the transmission of detection data is completed in a wired way. Because the bridge structure has many characteristics such as complex structure, large span, and harsh geographical environment, this brings many inevitable disadvantages to the bridge load detection: such as heavy wiring workload, easy introduction of interference signals, various lines The cables are not easy to distinguish, not easy to carry and transport, and the cost is higher.

With the rapid development of the transportation industry, the disadvantages of bridge load detection data wired transmission become more acute, and a detection system based on wireless sensor network has gradually come into people's sight. Developed countries such as the United States and Italy have successively made a lot of research on the wireless transmission of information and are becoming more and more mature. However, the price of foreign detection equipment is often relatively expensive. For example, the price of a wireless sensor node launched by the American Bridge Diagnostics Company is as high as 60,000 yuan, and the price of the whole set of equipment is even more expensive. This is obviously not suitable for my country's national conditions and people's needs. consumption level. Some domestic universities and research institutions are also engaged in research work in this area. However, so far, there has not been a complete and formed bridge load detection equipment realized by wireless sensor network in China.

Contents of the invention

The purpose of this utility model is to overcome the shortcomings of the above-mentioned prior art, and provide a bridge load detection device based on a wireless sensor network, which can realize functions such as collection, automatic processing, wireless transmission and analysis and evaluation of bridge static and dynamic load detection data .

The technical scheme of the utility model is realized in this way: seven power supply modules of the strain acquisition module, the deflection acquisition module, the acceleration acquisition module, the data processing module, the wireless transceiver module, the strain acquisition module and the data processing and the wireless transceiver module Module composition, the strain acquisition module, the deflection acquisition module and the acceleration acquisition module are respectively connected to the analog-to-digital conversion port of the data processing module; the data processing module communicates with the wireless transceiver module through the SPI bus; the data processing module and the auxiliary memory module are also based on the SPI bus Communication; the wireless transceiver module sink node SINK and its data transmission with the upper computer through serial communication, the power supply module of the strain acquisition module supplies power to the bias addition module of the strain acquisition module and the acceleration acquisition module respectively, data processing and wireless transceiver module The power supply module supplies power to the data processing module ATMega128L and the wireless transceiver module CC2420.

The strain acquisition module is composed of 1K strain gauges, precision fine-tuning potentiometers, AD620AN instrumentation amplifiers, bias modules, and strain acquisition power supply modules. Two 1K strain gauges and two precision fine-tuning potentiometers form a measuring bridge. Each half of the bridge arm is composed of a strain gauge and a precision fine-tuning potentiometer in series. At the non-ground end of the two potentiometers, two signal lines are drawn out as the differential input signal of the amplifier module.

The bias module is a voltage divider, which is composed of a 1K resistor and a 2K precision trimmer in series, and a voltage of +5V is added to both ends of it, and then a wire is drawn from the connection point of the resistor and the potentiometer. The signal line is connected to pin 5 of the instrumentation amplifier AD620AN to change the negative voltage into a positive voltage.

The deflection acquisition module is composed of the instrument battery 9V and the LVDT displacement sensor. Connect the positive and negative poles of the instrument battery to the two power lines of the LVDT displacement sensor respectively, and connect the two signal lines of the displacement sensor to the module of the data processing module. conversion port, either one of them and GND on the ground pin.

The acceleration acquisition module is composed of +5V power supply module, acceleration sensor YE5932A, and offset addition module. The offset addition module of this module consists of chip LM324, a 10K resistor, a 20K precision trimmer potentiometer and a 4.7uF electrolytic Capacitor composition, the signal collected by the acceleration sensor is sent to the negative terminal of the 4.7uF electrolytic capacitor, the 10K resistor and the 20K precision trimming potentiometer are connected in series, and the voltage of +3V is added to both ends of the electrolytic capacitor. The neutral end is connected to the connection point of the resistor and the potentiometer, and the signal line is drawn from this point to the 3 port of the LM324. At the same time, the 4 port of the LM324 is connected to +5V voltage, the 11 port is grounded, and the 1 and 2 ports are connected to each other. Port 1 of the final signal LM324 is sent to the analog-to-digital conversion ADC port, any one of them, so that the data processing module can process the data.

The power supply module of data processing and wireless transceiver module is +3.3V power supply module, which is composed of two dry batteries and chip MAX1678. Negative connection, port 8 outputs 3.3V voltage, a 47uH inductor is connected between port 1 and port 7, and a 10uF electrolytic capacitor is connected between port 8 and ground.

The power supply module of the strain acquisition module is composed of two dry batteries and the chip MAX631. Two dry batteries are used to provide an input voltage of 1.5V to 3.0V for the MAX631 chip. The 4 ports of the MAX631 are used as the input of the battery voltage, and the 1, 3 and 7 ports are grounded. Port 5 is used as the output port of the converted voltage, and a 330mH inductance is connected between port 4 and the positive pole of the battery, and a 0.1uF electrolytic capacitor is connected between port 5 and the ground.

This inspection utility model adopts the technology of wireless sensor network, and the data transmission adopts the wireless transmission mode based on ZigBeX protocol, which avoids the large-scale wiring of the wired transmission mode, reduces the detection cost, and improves the work efficiency of bridge detection.

Description of drawings

Fig. 1 is a structural block diagram of a wireless bridge load detection device;

Fig. 2 is a schematic block diagram of the strain acquisition module;

Fig. 3 is a functional block diagram of the bias module of the strain acquisition module;

Fig. 4 is a block diagram of the interface of the deflection acquisition module;

Fig. 5 is a block diagram of the interface of the acceleration acquisition module;

Fig. 6 is the functional block diagram of the offset addition module of the acceleration acquisition module;

Fig. 7 is a power supply block diagram of the strain acquisition module;

Fig. 8 is a power supply block diagram of data processing and wireless transceiver module;

Below in conjunction with accompanying drawing, the content of the present utility model is described in further detail.

Detailed ways

The utility model bridge load detection device based on wireless sensor network is composed of strain sensor, displacement sensor, acceleration sensor, acquisition amplification filter circuit, AVR single-chip microcomputer, radio frequency chip CC2420, power supply module circuit, download debugger, and computer. The bridge load detection device based on the wireless sensor network of the utility model is mainly composed of a sensor data acquisition module, a data processing module, and a data wireless transmission module (with data sending and receiving functions). Each module is independent of each other. The data processing module is connected to the data acquisition module through the ADC (analog-to-digital converter) port. The data wireless transmission module communicates with the data processing module through the SPI bus, and the data transmission module communicates through the serial port. Realize the connection with the host computer. The upper computer is responsible for monitoring each lower computer module, can issue routing information to the wireless transmission module, and can also receive and process detection data from each module, and display data information and waveforms. Each module executes the instructions of the upper computer and transmits the detection data to the upper computer. The UART interface circuit is responsible for the serial communication between the wireless transceiver module and the host computer.

First, use the TinyOS integrated development environment to compile the data processing and wireless transmission program, download the compiled target file to ATMega128L through AVRStudio, use the application program of the upper computer to set the relevant parameters of serial communication, and open the communication port, and at the same time, the upper computer The computer can also send the routing information obtained by the routing simulation platform to each sensor node in a wireless way. Then connect the output signals of the displacement sensor, acceleration sensor and strain signal conditioning module to the analog-to-digital conversion (ADC) port of ATMega128L. Then turn on the switch of each sensor node and SINK node, and the switch of communication between SINK node and host computer. Through the program of the upper computer, the data information of each sensor and the related waveform diagram can be seen. When the data collection is over, the data items collected this time can be generated into a report to realize on-site printing.

Referring to Fig. 1, the strain data acquisition module, the deflection data acquisition module and the acceleration data acquisition module are respectively connected to the analog-to-digital conversion (ADC) port of the data processing module. The core of the data processing module is the AVR microcontroller ATmega128L, and the processor internal Integrates eight 10-bit analog-to-digital conversion (ADC) conversion ports. In order to prolong the transmission distance in the process of wireless transmission, a multi-hop relay method is adopted. This method will make the processor of a certain node collect a large amount of data, and the storage space inside the processor is very limited. , adding an auxiliary memory module - AT45DB041, which contains 2048 pages, each page has a space of 264 bytes, thus greatly increasing the storage capacity of each processing node. The communication between the single chip microcomputer and the auxiliary memory is based on the SPI bus. The single chip microcomputer completes the read and write operation of the auxiliary memory under strict clock control according to the read and write operation code of the auxiliary memory. The radio frequency chip adopted by the wireless transceiver module - CC2420, the chip supports the 802.15.4 protocol, the frame format of MAC and PHY is automatically generated by the hardware, and it integrates digital modem module, analog-to-digital conversion (ADC), DAC, direct Up-conversion module, secondary frequency conversion low-intermediate frequency module, etc. It is because the power amplifier, low noise amplifier and mixer are integrated inside the chip, so that the peripheral circuit of the wireless transceiver module is relatively simple. The data communication between the single-chip microcomputer and the wireless transceiver module is also based on the SPI bus, and its corresponding ports SI, SO, CSN, and SCLK are respectively connected to the MOSI, MISO, SS, and SCK ports of the single-chip microcomputer to realize data communication. The signal transmitted by the RF communication of the device is a digital signal, the transmission frequency is 2.4G ~ 2.4835GHz, and there are 16 transmission channels in total. The transmission path is determined by the routing information generated by the routing simulation platform, so as to realize multi-hop wireless transmission of data. The communication between sink node (SINK) and upper computer adopts virtual serial communication. The power supply module of the strain acquisition module is also called a +5V power supply module, and the power supply module of the data processing and wireless transceiver module is also called a +3.3V power supply module.

Referring to Figure 2, in the strain acquisition module of the device, it is composed of a bridge, a weak signal amplification module and a +5V power supply module. The bridge contains two 1K strain gauges (respectively connected from BSGA1 and BSGA2), two fine-tuning potentiometers (R1 and R2), half of the bridge arm is composed of a strain gauge and a fine-tuning potentiometer It is formed in series, and at the non-ground ends of the two potentiometers, two signal lines are drawn out as the differential input signals of the amplifier module. Since the analog-to-digital conversion (ADC) port can only recognize positive voltage, and the amplified output of the differential signal has positive and negative signals, a bias module is added to the strain sensor module, as shown in Figure 3, it is a voltage divider composed of a A 1K (Rb) resistor and a 2K (ZER01) precision trimmer potentiometer are connected in series, and a voltage of +5V is added to both ends of it, and then a signal line is drawn from the connection point of the resistor and the potentiometer to be connected to the instrument amplifier AD620AN 5 pins are used to change the negative voltage into positive voltage. At the same time, both the electric bridge and the instrument amplifier module are powered by the +5V power supply module.

Referring to Figure 4, in the interface diagram of the deflection acquisition module, a 9V meter battery is used to power the LVDT displacement sensor. Since the deflection value of a general bridge under static load is usually very small, the largest will not exceed 3 cm, so if the position of the displacement sensor relative to the bridge is properly placed, the polarity of the voltage at both ends of the signal output line is not correct. changing. For this reason, the signal at the output of the displacement sensor can be directly connected to the analog-to-digital conversion (ADC) port of the processing module, and the processing module sends the A/D converted result into the analog-to-digital conversion (ADC) register as a wireless transceiver The data source for the module.

Referring to the interface diagram of the acceleration acquisition module shown in Figure 5, the acceleration sensor used in this device is within a reasonable output range (in the current gear, the pointer swing should exceed 1/3 of the range and be less than 2/3 of the range). Its output voltage range is between plus and minus 1V. In view of the fact that the analog-to-digital conversion (ADC) port cannot convert negative voltages, a bias addition module is introduced here, as shown in Figure 6, which consists of a chip LM324, a 10K resistor, a 20K precision trimmer and a 10uF Composed of electrolytic capacitors, it provides a 1.2V bias voltage for the output signal of the acceleration sensor. Send the signal collected by the acceleration sensor to the negative terminal of the 4.7uF electrolytic capacitor, connect a 10K resistor and a 20K precision trimmer in series, and add +3V (provided by two batteries) to both ends of the electrolytic capacitor. The positive terminal of the capacitor is connected to the connection point of the resistor and the potentiometer, and the signal line is drawn from this point to port 3 of the LM324. At the same time, port 4 of the LM324 is connected to +5V, port 11 is grounded, and ports 1 and 2 are connected to each other. The power supply of the bias addition module still uses the +5V power supply module. Then send the added signal (1 port of LM324) to the analog-to-digital conversion (ADC) port, so that the data processing module can process the data.

Referring to Figure 7, the power supply module of the strain acquisition module, that is, the +5V power supply module mentioned above, uses two dry batteries to provide an input voltage of 1.5V to 3.0V for the MAX631 chip, and the 4 ports of the MAX631 are used as the battery voltage. Input, ports 1, 3 and 7 are grounded, and port 5 is used as the output port of the converted voltage. When the battery power supply is normal, the output voltage of this port is +5V. At the same time, the peripheral circuit of MAX631 is very simple. A 330mH energy storage inductor is connected between port 4 and the positive pole of the battery, and a 100uF electrolytic capacitor is connected between port 5 and ground to remove noise.

As shown in Figure 8, the power supply module uses the MAX1678 chip, the positive input of two dry batteries is connected to its 1, 4, 7 ports, 5, 6 ports are connected to the negative pole of the battery, and the 8 port outputs a voltage of 3.3V. Connect a 47uH inductance between port 1 and port 7, connect a 10uF electrolytic capacitor between port 8 and ground. This module is mainly used to supply power to the chip of the data processing module and the wireless transceiver module.

Claims (7)

1. A bridge load detection device based on a wireless sensor network, characterized in that it consists of a strain acquisition module, a deflection acquisition module, an acceleration acquisition module, a data processing module, a wireless transceiver module, a power supply module of the strain acquisition module, data processing and a wireless transceiver The power supply module of the module consists of seven modules, the strain acquisition module, the deflection acquisition module and the acceleration acquisition module are respectively connected to the analog-to-digital conversion port of the data processing module; the data processing module communicates with the wireless transceiver module through the SPI bus; the data processing module communicates with the auxiliary The memory module is also based on SPI bus communication; the data transmission between the wireless transceiver module sink node SINK and the upper computer is through serial communication, and the power supply module of the strain acquisition module supplies power to the bias addition module of the strain acquisition module and the acceleration acquisition module respectively, and the data The power supply module of the processing and wireless transceiver module supplies power to the data processing module ATMega128L and the wireless transceiver module CC2420. 2. The bridge load detection device based on wireless sensor network according to claim 1, characterized in that the strain acquisition module consists of 1K strain gauges, precision trimmer potentiometers, instrumentation amplifier AD620AN, bias module and strain acquisition power supply module and other components, two 1K strain gauges and two fine-tuning potentiometers form a measuring bridge, and each half of the bridge arm is composed of a strain gauge and a precision fine-tuning potentiometer in series, between the two potentiometers The non-ground terminal leads out two signal lines as the differential input signal of the amplifier module. 3. The bridge load detection device based on wireless sensor network according to claim 2, characterized in that, the bias module is a voltage divider, which is connected in series by a 1K resistor and a 2K precision trimming potentiometer Composition, and a voltage of +5V is added to both ends of it, and then a signal line is drawn from the connection point of the resistor and the potentiometer to connect to pin 5 of the instrumentation amplifier AD620AN to change the negative voltage into a positive voltage. 4. The bridge load detection device based on a wireless sensor network according to claim 1, wherein the deflection acquisition module is composed of a meter battery 9V and an LVDT displacement sensor, and the positive and negative poles of the meter battery are respectively connected to the LVDT displacement sensor Connect the two signal wires of the displacement sensor to the analog-to-digital conversion port of the data processing module respectively, and connect any one of them to the GND ground pin. 5. The bridge load detection device based on wireless sensor network according to claim 1, characterized in that, the acceleration acquisition module is composed of +5V power supply module, acceleration sensor YE5932A, and offset addition module, and the offset addition module of this module It consists of a chip LM324, a 10K resistor, a 20K precision trimmer and a 4.7uF electrolytic capacitor. The signal collected by the acceleration sensor is sent to the negative terminal of the 4.7uF electrolytic capacitor, and the 10K resistor and 20K precision trimmer potentiometers are connected in series, and a voltage of +3V is added to both ends of the potentiometer. Port 4 of LM324 is connected to +5V voltage, port 11 is grounded, port 1 and port 2 are connected to each other, and the added signal 1 port of LM324 is sent to the analog-to-digital conversion ADC port, any one of which is used for data processing module. deal with. 6. The bridge load detection device based on wireless sensor network according to claim 1, characterized in that, the power supply module of the data processing and wireless transceiver module is a +3.3V power supply module, which is composed of two dry batteries and a chip MAX1678. The positive input of two dry batteries is connected to its 1, 4, 7 ports, 5, 6 ports are connected to the negative pole of the battery, 8 port outputs a voltage of 3.3V, a 47uH inductor is connected between 1 and 7 ports, 8 Connect a 10uF electrolytic capacitor between the port and ground. 7. The bridge load detection device based on a wireless sensor network according to claim 1, wherein the power supply module of the strain acquisition module is composed of two dry batteries and a chip MAX631, and the two dry batteries provide 1.5V to 1.5V for the MAX631 chip. 3.0V input voltage, port 4 of MAX631 is used as the input of the battery voltage, ports 1, 3 and 7 are grounded, port 5 is used as the output port of the converted voltage, and a 330mH inductor is connected between port 4 and the positive pole of the battery. Connect a 0.1uF electrolytic capacitor between the port and ground.

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