CN105067099A - Method used for subway environment vibration and noise combined test and system thereof - Google Patents

Abstract

A method for joint testing of subway environmental vibration and noise. By arranging a group of wireless nodes in the selected measurement area around the subway to obtain data on the vibration and noise of the surrounding environment of the subway, each node is equipped with vibration acceleration and noise on-site through the BNC interface. Or sound level sensor, the collected acceleration and sound pressure data are converted into the weighted vibration level and sound level in the environmental assessment through the embedded DSP chip of the node; all wireless nodes are in a wireless sensor network, and the time synchronization is completed through the internal clock. After a test is completed, all test data and processing results are wirelessly transmitted to the base station connected to a group of wireless nodes and finally stored on the PC side; the wireless nodes use Zigbee-based wireless nodes. The invention is easy to install and flexible to use, and can simultaneously collect the vibration and noise data of the subway environment in real time.

Description

A method and system for joint testing of subway environmental vibration and noise

technical field

The invention relates to the field of vibration and noise environment monitoring of urban rail transit, and proposes a method and system for joint testing of subway environment vibration and noise.

Background technique

With the development of my country's social economy, the rapid development of the subway transportation system, while bringing convenience, the problems of environmental vibration and noise caused by its operation have become increasingly prominent, which has brought certain troubles to the daily life and work of the surrounding people, and even affected to human health. The analysis and evaluation of environmental vibration and noise caused by urban subway operation has become a research hotspot in recent years. Traditional evaluation methods only use a single vibration or noise as an evaluation reference, and cannot comprehensively and accurately analyze and evaluate the engineering and noise caused by subway operation. Environmental issues.

Contents of the invention

In view of the above deficiencies, the purpose of the present invention is to provide a method and system for joint testing of subway environment vibration and noise, through which the vibration and noise levels in the subway environment can be flexibly and quickly obtained, and the evaluation of the surrounding environment of the subway can be realized. It is convenient for the investigation of vibration and noise pollution in the surrounding area of the subway and the work of earthquake prevention and noise reduction.

In order to achieve the above object, the technical steps of the present invention are as follows: a method and system for joint testing of subway environmental vibration and noise; by arranging a group of wireless nodes in the selected measurement area around the subway, the vibration and noise of the surrounding environment of the subway can be obtained. Each node is equipped with vibration acceleration and noise or sound level sensors on site through the BNC interface, and the collected acceleration and sound pressure data are converted into the weighted vibration level and sound level in the environmental assessment through the embedded DSP chip of the node; all wireless nodes are co-located In a wireless sensor network, the internal clock is used to complete time synchronization. After a test is completed, all test data and processing results are wirelessly transmitted to the base station connected to a group of wireless nodes and finally stored on the PC side; the wireless nodes adopt Zigbee-based wireless nodes for communication;

a. Arrange the nodes according to the site conditions, and connect the vibration and noise sensors to the nodes through the BNC interface; based on Zigbee communication technology, use a wireless sensor network composed of nodes, base stations, and PCs to adjust the sampling frequency, sampling time, and node time synchronization; , the vibration acceleration sensor needs to be tightly fixed on the floor of the test area, and the noise sensor needs to be suspended 1.2m above the floor of the test area;

b. Node data acquisition and processing: The vibration and noise analog signals collected by the terminal sensor are first amplified by the signal amplifier (OP2177 operational amplifier) built in the node; then filtered by the low-pass filter (MAX29X series); then the analog signal is passed through The ADC circuit (AD7766 chip) converts it into a digital signal, and then the embedded DSP chip (TMS320F28335 chip) completes the data conversion processing (acceleration sensor signal is converted into weighted vibration level, and noise sensor is converted into sound level (weighted sound level).

Among them, the formula for converting vibration acceleration to weighted vibration level is as follows:

$\mathrm{<span\; class="notranslate">\; V</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; lg</span>}\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

In the formula, a ₀ is the reference acceleration, which takes a value of 10 ^-6 m/s ² ; a _w is the root mean square of the weighted acceleration, which represents the effective value of the weighted acceleration within a certain period of time, expressed as:

${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&lsqb;</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&rsqb;</span>}^{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula, a _i corresponds to the acceleration of each center frequency multiplied by one-third frequency; w _i is the accelerometer weight factor of each center frequency, referring to IS02631-1997, the formula is as follows:

${\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0.5</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; 0.5</span>}}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 4</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 8</span>}\\ \mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 80</span>}\end{array}\right.$

In addition, the formula for converting sound pressure to sound pressure level is as follows:

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; lg</span>}\frac{\mathrm{<span\; class="notranslate">\; P</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

In the formula, P ₀ is the reference acceleration, the value is 2×10 ^-5 m/s ² ; P is the sound pressure value obtained from the test.

Substituting the calculated sound pressure level L _P into the 40-square curve in the equal loudness curve specified in ISO226-2003, the A sound level can be obtained, which is denoted as L _AE .

c. Data storage and result output: After completing a data collection, the processed data is transmitted to the base station via the wireless transmission protocol, and then transferred to the PC via the base station.

Each node can be connected to a vibration acceleration sensor and a sound pressure sensor through a BNC interface, and simultaneously collect on-site vibration acceleration (m/s ² ) and noise sound pressure data (Pa).

By programming the DSP chip embedded in the wireless node, the data can be directly converted into the weighted vibration level (dB) and A-weighted sound level (dB) commonly used in environmental assessment within the node.

A system for joint testing of subway environment vibration and noise is characterized in that it uses the Zigbee wireless transmission protocol to self-assemble a wireless sensor network. The whole system includes a group of terminal nodes, base stations, and PCs to form a wireless sensor network based on Zigbee communication. Each node is time-synchronized by an internal clock; each node can be connected to a vibration acceleration sensor and a sound pressure sensor through a BNC interface, and simultaneously collect vibration acceleration and sound pressure level data. The sensor needs to be suspended 1.2m above the floor of the measurement area; connect the vibration and noise sensor to the node through the BNC interface;

Each node is equipped with vibration acceleration and noise or sound level sensors on site through the BNC interface, and the collected acceleration and sound pressure data are converted into the weighted vibration level and sound level in the environmental assessment through the embedded DSP chip of the node; all test data and processing results are Wireless transmission to a base station connected to a group of wireless nodes and finally stored on the PC;

The vibration and noise analog signal collected by the sensor of the terminal node is first amplified by the signal amplifier OP2177 operational amplifier built in the node; then filtered by the low-pass filter (MAX29X series); then the analog signal is converted into The digital signal is then converted and processed by the embedded DSP chip (TMS320F28335 chip) (acceleration sensor signal is converted into weighted vibration level, and noise sensor is converted into sound level (weighted sound level).

Each module in the node adopts low-power miniature electronic components (OP2177 signal amplifier, MAX29X series 8-order low-pass switched capacitor filter, AD7766 circuit, TMS320F28335 chip), which are easy to install and quick to replace. The node has a built-in rechargeable lithium battery to meet the continuous work of more than 8 hours.

It can be seen from the above technical solution of the present invention that the beneficial effect of the present invention is that, compared with the conventional test: the present invention adopts the wireless transmission mode and the node self-assigns the power supply unit, which avoids the on-site wire pulling and wiring work; the vibration acceleration around the subway can be obtained at the same time and noise change data, and can be directly converted into the weighted vibration level and A sound level commonly used in environmental assessment within the node, avoiding the complicated post-data processing process. The invention can provide convenience for the investigation of vibration and noise pollution in the surrounding areas of the subway and the work of shockproof and noise reduction.

Description of drawings

Fig. 1 is the system work flowchart of the present invention.

Fig. 2 is a system structure diagram of the present invention.

FIG. 3 is a structural diagram of a wireless sensor node of the present invention.

Fig. 4 is a flow chart of internal operation of nodes in the present invention.

Figure 5 shows the vibration acceleration collected by the nodes in the calculation example and the weighted vibration level change results after self-processing.

Figure 6 shows the sound pressure collected by the nodes in the calculation example and the A sound level change results after processing.

Detailed ways

The present invention will be described in detail below in conjunction with the accompanying drawings and specific examples, but the scope of application of the present invention is not limited thereto.

Combined with Figure 1, the transmission of vibration and noise generated by subway operation in the surrounding environment will affect the work and quality of life of the surrounding population. Generally, conventional environmental tests only consider a single vibration or noise factor. This invention adopts a group of wireless sensor nodes to be deployed in the target area, which can simultaneously acquire environmental vibration and noise data, and output the weighted vibration level of the environment through internal processing of the nodes. and A sound level, and save it on the PC side. The obtained results can be used as a reference for the management department in order to carry out targeted control and treatment of environmental vibration and noise pollution in a timely manner.

Referring to Fig. 2, the system configuration of the present invention includes a group of wireless sensor nodes, a base station and a PC terminal. Any sensor node is connected with a vibration acceleration sensor and a sound pressure sensor, which can collect vibration acceleration and sound pressure data at the same time, and complete the data conversion calculation inside the node. After the test is completed, the processing results stored in the node can be wirelessly The transmission protocol is transferred to the base station, which can be further stored on the PC side via the base station.

Referring to FIG. 3 , the wireless sensor node of the present invention is composed of a signal acquisition module (external vibration and noise sensor), a signal adjustment module, a data processing module, a wireless communication module and a power supply module. The node is connected to the external sensor module through the BNC interface, which are the IEPE type AI500 acceleration sensor and the capacitive AWA14423 microphone, which are used to collect vibration and noise signals; through the OP2177 signal amplifier in the signal conditioning module, MAX29X series 8-order low-pass switched capacitor filter , to achieve analog signal amplification and anti-aliasing low-pass filtering; the data calculation processing module first converts the analog signal into a numerical signal through the AD7766 analog-to-digital conversion circuit, and then performs real-time calculation on the data through the embedded programming DSP chip (TMS320F28335 chip) Processing; the wireless communication module uses a general-purpose Zigbee communication component, which is responsible for the self-organizing network construction of each node and the wireless transmission of data; the power supply module is responsible for the energy supply of the entire node, which is a rechargeable lithium battery.

In conjunction with Fig. 4, the brief steps of data collection and processing of the present invention are as follows:

The first step: self-organizing wireless sensor network, by calling the Cygwin software on the PC side, the preset sampling frequency is 280Hz, the sampling time is 100s, and the nodes are time-synchronized.

Step 2: Collect vibration and noise data, perform adaptive analog signal amplification and filtering, and perform calculation processing on the acquired data in the DSP chip inside the node.

In this step, calculate the weighted vibration level according to the filtered vibration acceleration, the formula is as follows:

$\mathrm{<span\; class="notranslate">\; V</span>}\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; lg</span>}\frac{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}}{{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

In the formula, a ₀ is the reference acceleration, which takes a value of 10 ^-6 m/s ² ; a _w is the root mean square of the weighted acceleration, which represents the effective value of the weighted acceleration within a certain period of time, expressed as:

${\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; =</span>{<span\; class="notranslate">\; \&lsqb;</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}{\mathrm{<span\; class="notranslate">\; a</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; \&rsqb;</span>}^{\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}}$

In the formula, a _i corresponds to the acceleration of each center frequency on the one-third octave band; w _i is the accelerometer weight factor of each center frequency, referring to IS02631-1997, the formula is as follows:

${\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}<span\; class="notranslate">\; =</span>\left\{\begin{array}{cc}\mathrm{<span\; class="notranslate">\; 0.5</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{\mathrm{<span\; class="notranslate">\; 0.5</span>}}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 4</span>}\\ \mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 8</span>}\\ \mathrm{<span\; class="notranslate">\; 8</span>}{\mathrm{<span\; class="notranslate">\; f</span>}}^{<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>& \mathrm{<span\; class="notranslate">\; 8</span>}<span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 80</span>}\end{array}\right.$

At the same time, the A sound level is calculated according to the filtered sound pressure level, the formula is as follows:

${\mathrm{<span\; class="notranslate">\; L</span>}}_{\mathrm{<span\; class="notranslate">\; P</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 20</span>}\mathrm{<span\; class="notranslate">\; lg</span>}\frac{\mathrm{<span\; class="notranslate">\; P</span>}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

In the formula, P ₀ is the reference acceleration, the value is 2×10 ^-5 m/s ² ; P is the sound pressure value obtained from the test.

Substitute the sound pressure level L _P into the 40-square equal loudness curve to obtain the A sound level data, which is denoted as L _AE .

Step 3: After the test is completed, the original data and processing results are transmitted to the base station through the wireless protocol, and finally stored on the PC.

Figure 5 shows the initial vibration acceleration data collected by an example node in an underground building around a subway directly output on the PC side and the weighted vibration level results after internal processing.

Figure 6 shows the initial sound pressure data collected by an example node in an underground building around a subway directly output on the PC side and the A sound level results after internal processing.

Combining FIG. 5 and FIG. 6, it can be seen that the present invention can quickly realize the conversion of environmental evaluation indicators, and avoid complicated post-processing data processing. Using the test data and processing results, and referring to the relevant vibration and noise norms and standards, the subway environment can be quickly evaluated, and it can provide guidance for the post-seismic noise reduction work.

Claims (6)

1. the method for metro environment vibration and noise joint test, it is characterized in that laying one group of radio node by laying one group of radio node in subway periphery selected survey district, obtain the data of subway surrounding enviroment vibration and noise, each node is equipped with vibration acceleration and noise or sound level sensor by bnc interface scene, and the acceleration of collection and acoustic pressure data are scaled weighted in environmental evaluation by the embedded dsp chip of node and shake level and sound level; All radio nodes are altogether in a radio sensing network, synchronous by the internal clocking deadline, and after completing once test, all test datas and result are all wirelessly transmitted to the base station is connected with one group of radio node and are also finally stored in PC and hold; Radio node adopts the radio node based on Zigbee communication;

A. lay node according to field condition, vibration and noise sensor is connected with node by bnc interface; Adopting the radio sensing network that node, base station and PC form, by calling the predeterminable sample frequency of Cygwin software, sampling duration at PC end, and time synchronized being carried out to node; Wherein, vibration acceleration sensor need closely be fixed on the floor of test zone, and noise transducer then needs to hang on surveys 1.2m place on floor, district;

B. node data Acquire and process: the vibration of end sensor collection and noisy analog signal first carry out signal amplification by the signal amplifier that node is built-in; Enter low-pass filter (MAX29X series) again and carry out filtering; Then simulating signal transfers digital signal to by adc circuit, then completes the conversion process of data by embedded dsp chip, and acceleration transducer signals is converted to weighted and shakes level, and noise transducer converts weighted sound level to.

2. the method for vibration and noise joint test according to claim 1, is characterized in that vibration acceleration is converted to the shake formula of level of weighted as follows:

$VL=20\lg \frac{a_w}{a_0}$

In formula, a ₀for reference acceleration, value 10 ^-6m/s ²; a _wfor weighted acceleration root mean square, represent the effective value of weighted acceleration in certain hour, be formulated as:

$a_w={\&lsqb;\underset{i}{\&Sigma;}{\left(w_i{a}_i\right)}^2\&rsqb;}^{\frac{1}{2}}$

In formula, a _icorresponding 1/3rd frequencys multiplication take advantage of the acceleration of each centre frequency; w _ifor each centre frequency accelerometer weight factor, formula is as follows:

$w_i=\left\{\begin{array}{cc}0.5f^{0.5},& 0\&le;f\&le;4\\ 1,& 4<f<8\\ 8f^{-1},& 8<f\&le;80\end{array}\right.$

In addition, to be converted to the formula of sound pressure level as follows for acoustic pressure:

$L_P=20\lg \frac{P}{P_0}$

In formula, P ₀for reference acceleration, value 2 × 10 ^-5m/s ²; P is the sound pressure level of test gained;

Calculate the sound pressure level L of gained _pthe 40 side's curves substituted in the equal loudness contour of ISO226-2003 can obtain A sound level, are designated as L _aE;

C. data store and result output: after completing a data acquisition, the data after process pass to base station via wireless transmission protocol, then dump to PC end via base station.

3. the method for vibration and noise joint test according to claim 1, is characterized in that each node all connects vibration acceleration sensor and sound pressure sensor by bnc interface, simultaneously collection site vibration acceleration (m/s ²) and noise acoustic pressure data (Pa).

4. the method for vibration and noise joint test according to claim 1, it is characterized in that by embedding dsp chip programming to radio node, data to be directly scaled in environmental evaluation conventional weighted at intra-node and to shake level (dB) and A-weighted sound level (dB).

5., for a system for metro environment vibration and noise joint test, it is characterized in that comprising one group of terminal node, base station, PC composition based on the radio sensing network of Zigbee communication, each node is synchronous by the internal clocking deadline; Each node all can connect vibration acceleration sensor and sound pressure sensor by bnc interface, gather vibration acceleration and sound pressure level data simultaneously, vibration acceleration sensor need closely be fixed on the floor of test zone, and noise transducer then needs to hang on surveys 1.2m place on floor, district; Vibration and noise sensor is connected with node by bnc interface;

Each node is equipped with vibration acceleration and noise or sound level sensor by bnc interface scene, and the acceleration of collection and acoustic pressure data are scaled weighted in environmental evaluation by the embedded dsp chip of node and shake level and sound level; All test datas and result are all wirelessly transmitted to the base station that is connected with one group of radio node and are finally stored in PC and hold.

6. the system of vibration and noise joint test according to claim 5, is characterized in that the vibration of the sensor collection of terminal node and noisy analog signal first carry out signal amplification by the signal amplifier OP2177 operational amplifier that node is built-in; Enter low-pass filter again and carry out filtering; Then simulating signal transfers digital signal to by adc circuit, then completes the conversion process of data by embedded dsp chip.