CN111257237A - High-rise building security system design method based on surface acoustic waves - Google Patents

Abstract

The invention relates to a design method for a high-rise building security system based on surface acoustic waves. First, by utilizing the flexible characteristics of unmanned aerial vehicles, a laser surface acoustic wave sensor is mounted on an unmanned aerial vehicle platform, and then path planning is performed on the unmanned aerial vehicle, so that the The laser surface acoustic wave sensor can comprehensively scan high-rise buildings, and detect and characterize material surface damage by applying the laser surface acoustic wave detection method. According to the data measured by the laser surface acoustic wave sensor, the health status of the high-rise building wall to evaluate. By regularly assessing the health of the walls of high-rise buildings, the hidden safety problems of high-rise buildings can be solved in a timely and effective manner.

Description

A design method of high-rise building security system based on surface acoustic wave

technical field

The invention relates to the field of building security, and particularly designs a building wall health estimation method based on surface acoustic waves.

Background technique

With the development of society and economy, the process of urbanization in my country is accelerating. my country has a large population base, intensive construction, and generally high building heights. People pay more and more attention to the safety and beauty of buildings. Cracks in buildings affect building structures. The integrity and use function of the structure will also cause insecurity to the user, but as long as the crack does not endanger the structural safety and use, it is easy to be ignored by people, and it is easy to cause hidden safety hazards in the building. Not only that, a large number of buildings have been in service for a long time. Under the action of random loads such as earthquake loads, buildings are often prone to premise damage. Therefore, corresponding preventive measures should be taken in the process of building design and construction to effectively control cracks. .

The laser surface acoustic wave inspection method belongs to the category of laser ultrasonic inspection and is a new research direction in the field of non-destructive inspection. The laser surface acoustic wave method mainly uses the dispersion characteristics of the surface acoustic wave in the sample material to detect the damage of the material surface. The characteristic of the surface acoustic wave is that when it propagates in the material without damage, its wave speed is only related to the characteristic parameters of the propagating medium material. change, there is dispersion phenomenon.

UAVs have the characteristics of flexible action, especially for high-rise buildings, the use of UAVs can greatly experience the advantages of their flexibility.

Therefore, surface acoustic wave technology can be used to detect wall cracks based on drones, and then evaluate the health of the wall.

SUMMARY OF THE INVENTION

In order to solve the above problems. The invention provides a design method for a high-rise building security system based on surface acoustic waves, and solves the problem of crack detection in a high-rise building wall. For this purpose:

The present invention provides a high-rise building security system design method based on surface acoustic waves, and the specific steps are as follows:

Step 1: Build a detection drone platform system, which can intelligently plan paths based on drones, and scan building walls efficiently and quickly, including: power supply module, drive module, motor module, voltage detection module, obstacle avoidance Sensing module, storage module, camera module, laser surface acoustic wave module, etc.;

Step 2: Use the voltage detection module to detect the power of the power supply module by detecting the UAV system platform. When the power is too low, the UAV control system controls the UAV to land charging, and the obstacle avoidance ultrasonic module detects the obstacle information of the path and selects it. avoid obstacles;

Step 3: The camera module collects the contour information of the wall, and uses the ultrasonic module to detect the distance to the wall, uses the camera and the ultrasonic module to collect information, and the controller controls the drone to fly and scan equidistantly along the wall;

Step 4: When the drone flies along the wall, use the laser surface acoustic wave sensor to detect the dispersion information of the wall surface acoustic wave to evaluate the health of the wall.

As a further improvement of the present invention, the detection UAV platform system in the step 1 is composed as follows:

The experimental platform includes hardware systems; UAV controller, power module, drive module, motor module, voltage detection module, ultrasonic module, storage module, camera module, laser surface acoustic wave module, etc.

As a further improvement of the present invention, the ultrasonic ranging scheme in the step 2 is as follows:

The ultrasonic measurement distance formula is shown in Equation 1:

Among them, s is the measurement distance, v is the speed of sound, the specific value is 340m/s, and t is the sampling period;

The sampling process will be affected by noise. Therefore, the ultrasonic ranging uses mean filtering, and the formula is shown in Equation 2:

为滤波后的距离值，s_i为超声波测量的实际值，n滤波窗的长度。in,

is the filtered distance value, s _i is the actual value of ultrasonic measurement, and n is the length of the filtering window.

As a further improvement of the present invention, the camera image processing scheme in step 3 is as follows:

In order to separate the building wall from the background, the image is binarized, and the gray value of each pixel on the image is subjected to a threshold division and judgment, that is, the fixed threshold method; The gray value of the point is compared with the threshold value. The pixel group whose gray value is greater than the threshold value in the original image is the detection object and is marked as 1; It becomes a single 0 and 1 single-channel image, and the mathematical form of grayscale image binarization is shown in Equation 3:

Among them, T is the selected threshold; f(X, Y) is the gray value of each pixel.

As a further improvement of the present invention, in the step 4, the surface acoustic wave data is calculated as follows:

Among them, V _i is the phase velocity corresponding to different frequencies of the surface acoustic wave, n is the quantized number of the surface acoustic wave, and D represents the smoothness of the dispersion curve of the surface acoustic wave;

The determination of the building wall is shown in formula 5:

Among them, T is the threshold value of the smoothness of the dispersion curve of the wall surface acoustic wave, and the H value represents the health status of the wall. The larger the H value, the worse the health status of the wall.

The invention based on the surface acoustic wave based high-rise building security system design method, the beneficial effects are:

1. The present invention uses laser surface acoustic wave to detect wall surface cracks, the detection is not affected by the environment, and the detection accuracy is increased;

2.Using the drone platform for wall scanning, increasing the flexibility of volume and wide scanning range;

3. The algorithm of the present invention is simple, the realization is simple, and the hardware cost is low.

Description of drawings

Figure 1 is the overall block diagram of the system;

Figure 2 is the working principle diagram of the system;

Figure 3 is the UAV path planning diagram.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments:

Step 1: Build a detection drone platform system, which can intelligently plan paths based on drones, and scan building walls efficiently and quickly, including: power supply module, drive module, motor module, voltage detection module, obstacle avoidance Sensing module, storage module, camera module, laser surface acoustic wave module, etc., as shown in Figure 1;

In step 1, the detection UAV platform system is composed as follows:

The experimental platform includes hardware systems; UAV controller, power module, drive module, motor module, voltage detection module, ultrasonic module, storage module, camera module, laser surface acoustic wave module, etc.

Step 2: Use the voltage detection module to detect the power of the power supply module by detecting the UAV system platform. When the power is too low, the UAV control system controls the UAV to land charging, and the obstacle avoidance ultrasonic module detects the obstacle information of the path and selects it. To avoid obstacles, the system work flow chart is shown in Figure 2;

The ultrasonic ranging scheme in step 2 is as follows:

The ultrasonic measurement distance formula is shown in Equation 1:

Among them, s is the measurement distance, v is the speed of sound, the specific value is 340m/s, and t is the sampling period;

The sampling process will be affected by noise. Therefore, the ultrasonic ranging uses mean filtering, and the formula is shown in Equation 2:

为滤波后的距离值，s_i为超声波测量的实际值，n滤波窗的长度。in,

is the filtered distance value, s _i is the actual value of ultrasonic measurement, and n is the length of the filtering window.

Step 3: The camera module collects the contour information of the wall, and the ultrasonic module is used to detect the distance from the wall. The camera and the ultrasonic module are used to collect information. The controller controls the drone to fly and scan along the wall at an equal distance, and the drone scans the path. The plan is shown in Figure 3;

The camera image processing scheme in step 3 is as follows:

In order to separate the building wall from the background, the image is binarized, and the gray value of each pixel on the image is subjected to a threshold division and judgment, that is, the fixed threshold method; The gray value of the point is compared with the threshold value, and the pixel group whose gray value is greater than the threshold value in the original image is the detection object, which is marked as 1; the pixel group less than the threshold value will be marked as 0 as the background; in this way, the final image information becomes It becomes a single 0 and 1 single-channel image, and the mathematical form of grayscale image binarization is shown in Equation 3:

Among them, T is the selected threshold; f(X, Y) is the gray value of each pixel.

Step 4: When the drone flies along the wall, use the laser surface acoustic wave sensor to detect the dispersion information of the wall surface acoustic wave to evaluate the health of the wall;

In step 4, the surface acoustic wave data is calculated as follows:

Among them, V _i is the phase velocity corresponding to different frequencies of the surface acoustic wave, n is the quantized number of the surface acoustic wave, and D represents the smoothness of the dispersion curve of the surface acoustic wave;

The determination of the building wall is shown in formula 5:

Among them, T is the threshold value of the smoothness of the dispersion curve of the wall surface acoustic wave, and the H value represents the health status of the wall. The larger the H value, the worse the health status of the wall.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any other form, and any modifications or equivalent changes made according to the technical essence of the present invention still fall within the scope of protection of the present invention. .

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any other form, and any modifications or equivalent changes made according to the technical essence of the present invention still fall within the scope of protection of the present invention. .

Claims (5)

1. A high-rise building security system design method based on surface acoustic waves comprises the following specific steps,

step 1: build and detect unmanned aerial vehicle platform system, this platform can carry out the route planning based on unmanned aerial vehicle intelligence, and high-efficient, quick building wall body that carries on scans, include: the device comprises a power supply module, a driving module, a motor module, a voltage detection module, an obstacle avoidance sensing module, a storage module, a camera module, a laser surface acoustic wave module and the like;

step 2: the unmanned aerial vehicle control system controls the unmanned aerial vehicle to land for charging when the electric quantity is too low, and the obstacle avoidance ultrasonic module detects obstacle information of a path and selectively avoids obstacles;

and step 3: the camera module collects wall surface contour information, the ultrasonic module is used for detecting the distance between the camera module and the wall body, the camera module and the ultrasonic module are used for collecting information, and the controller controls the unmanned aerial vehicle to fly and scan along the wall body at equal intervals;

and 4, step 4: when the unmanned aerial vehicle flies along the wall surface, the laser surface acoustic wave sensor is used for detecting the surface acoustic wave propagation dispersion information of the wall surface to evaluate the health condition of the wall surface.

2. The high-rise building security system design method based on the surface acoustic wave according to claim 1, characterized in that; the unmanned aerial vehicle platform system for detection in the step 1 comprises the following components:

the experiment platform comprises a hardware system: unmanned aerial vehicle controller, power module, drive module, motor module, voltage detection module, ultrasonic wave module, storage module, camera module, laser surface acoustic wave module etc..

3. The high-rise building security system design method based on the surface acoustic wave according to claim 1, characterized in that; the ultrasonic ranging scheme in step 2 is as follows:

the ultrasonic measurement distance formula is shown in formula 1:

wherein s is a measurement distance, v is a sound velocity, a specific value is 340m/s, and t is a sampling period;

noise influence exists in the sampling process, so the ultrasonic ranging uses mean filtering, and the formula is as shown in formula 2:

wherein,

is a filtered distance value, s_iThe length of the n filter windows is the actual value of the ultrasonic measurement.

4. The high-rise building security system design method based on the surface acoustic wave according to claim 1, characterized in that; the camera image processing scheme in step 3 is as follows:

in order to separate the building wall from the background, the image is subjected to binarization processing, and the gray value of each pixel point on the image is subjected to threshold division and discrimination, namely a fixed threshold method; setting a threshold, comparing the gray value of each pixel with the threshold, marking the pixel group with the gray value larger than the threshold in the original image as a detection object as 1, and marking the pixel group with the gray value smaller than the threshold as 0 as a background; thus, the finally obtained image information becomes a single 0 and 1 single channel image, and the binary mathematical form of the gray level image is shown as formula 3:

wherein T is a selected threshold; f (X, Y) is the gray value of each pixel point.

5. The surface acoustic wave-based high-rise building security system design method according to claim 1, detecting the dispersion information of the surface acoustic wave propagation of the wall by using a laser surface acoustic wave sensor, and is characterized in that; the surface acoustic wave data in step 4 is calculated as follows:

wherein, V_iPhase velocities corresponding to different frequencies of the surface acoustic waves are obtained, n is the number of the surface acoustic waves after quantization, and D represents the stability degree of a dispersion curve of the surface acoustic waves;

the judgment of the building wall is shown in formula 5:

wherein, T is the threshold value of the stationary degree of the dispersion curve of the surface acoustic wave of the wall, H value represents the health condition of the wall, the larger the H value is, the worse the health condition of the wall is represented.

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