A nondestructive testing device for quality of road asphalt pavement

Abstract

The application discloses a kind of road asphalt surface layer quality nondestructive testing device, it is related to measurement technical field, including vehicle body, the detection beam of being installed in the rear end of vehicle body by balance frame system and the optical detection component of being symmetrically installed in the bottom of detection beam, the optical detection component includes: guide rail swing mechanism, it is rotated with the detection beam by vertically arranged rotation fulcrum shaft connection, and can be driven by rotation drive module and periodically swing between first preset angle and second preset angle;Visual scanning unit.The guide rail swing mechanism of the application periodically swings between preset angle, cooperates with the transverse sliding of sliding seat along guide rail, combines the rectangular field of view of visual scanning unit, without multiple start-stop vehicle body adjustment position, can cover the transverse area of standard lane once;Vehicle body moving speed and field of view covering capacity, sliding seat speed design, make the image collected in front and back naturally form overlap, save complex data splicing step later.

Description

Technical Field

[0001] This invention relates to the field of measurement technology, specifically to a metrological device characterized by optical methods, and more specifically to a non-destructive testing device for the quality of road asphalt surface layer. Background Technology

[0002] As the core structural layer of road engineering, the construction quality of asphalt pavement directly affects the service life, driving safety, and comfort of the road. Therefore, efficient and accurate quality testing is a crucial aspect of asphalt pavement construction and maintenance. However, current mainstream asphalt pavement quality testing methods still have many limitations and cannot meet the demands for refined and efficient testing.

[0003] Traditional testing methods rely heavily on manual operation and semi-automated equipment. For example, the 3-meter straightedge measurement method requires manual placement of the straightedge against the road surface to interpret the gap value. This not only results in extremely low efficiency but is also susceptible to subjective factors such as the operator's hand strength and visual angle, making it impossible to accurately capture subtle flatness deviations. While continuous flatness meters can achieve continuous measurement, the equipment's reference frame depends on the road surface for support. During movement, it is easily affected by local bumps and depressions in the road surface, causing the reference line to shift. The measurement accuracy decreases with increasing testing distance, especially in areas with damaged road surfaces where the error is even greater.

[0004] Destructive testing methods such as core drilling and pit digging can obtain internal structural parameters of the road surface, but they directly damage the asphalt surface structure. After sampling, backfilling and repair are required, which not only increases construction costs but also affects road traffic. Moreover, due to the limited number of sampling points, the sampling results are not representative enough and cannot reflect the overall quality distribution of the road surface, making it easy to miss local hidden defects.

[0005] While existing technologies include mounting optical sensors on vehicles for mobile inspection, these technologies still have certain drawbacks. Most devices use fixed optical sensors (such as single cameras or single laser rangefinders), whose lateral detection range is limited by the sensor's own field of view. To cover standard lanes, the vehicle needs to be started and stopped multiple times to adjust the detection position, or multiple sets of discrete data need to be stitched together later. Multiple moves not only delay the construction progress but also easily lead to blind spots at the data stitching points due to vehicle positioning deviations. Furthermore, the lack of real-time displacement calibration during later stitching can easily result in elevation data discontinuities, further reducing the reliability of the inspection results. Therefore, these technologies still cannot meet the high-quality and high-efficiency inspection requirements for asphalt pavements. Summary of the Invention

[0006] The purpose of this invention is to provide a non-destructive testing device for the quality of road asphalt surface layer, so as to solve the problems mentioned in the background art.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] This invention provides a non-destructive testing device for the quality of road asphalt surface layer, comprising a vehicle body, a testing beam mounted at the rear end of the vehicle body via a balance frame system, and optical testing components symmetrically mounted at the bottom of the testing beam. The optical testing components include:

[0009] The guide rail swing mechanism is rotatably connected to the detection beam through a vertically set rotating fulcrum shaft, and can be driven by a rotation drive module to swing periodically between a first preset angle and a second preset angle.

[0010] A visual scanning unit is mounted on a sliding seat via an angle adjustment structure. The sliding seat is slidably mounted on the guide rail swing mechanism via a linear drive module. The visual scanning unit has a rectangular field of view perpendicular to the vehicle's forward direction and is used to continuously acquire images of the road surface's transverse area and calculate the elevation data of that area based on the principle of stereo vision.

[0011] The rotary drive module and the linear drive module work together. When the guide rail swing mechanism swings to the first preset angle or the second preset angle, the guide rail swing mechanism forms a specific angle with the vehicle's forward direction. This allows the linear drive module to drive the sliding seat to slide along the guide rail. The component of the sliding seat's velocity in the vehicle's forward direction is equal in magnitude and opposite in direction to the vehicle's forward velocity. This keeps the visual scanning unit relatively stationary relative to the road surface in the vehicle's forward direction at the moment of data acquisition. The sliding seat's lateral velocity drives the visual scanning unit to continuously cover and acquire the complete lateral area of ​​the road surface.

[0012] Furthermore, the visual scanning unit is a binocular vision component, which includes two parallel image acquisition units. The optical axes of the two image acquisition units are kept parallel and the spacing is fixed, and they jointly cover the rectangular field of view. Road surface elevation data is obtained through parallax calculation.

[0013] Furthermore, it also includes a data processing unit, which is used to receive the regional image collected by the visual scanning unit, and perform three-dimensional reconstruction on the regional image to calculate the elevation data of each point on the road surface. At the same time, it combines the lateral displacement data of the sliding seat to stitch together the continuously collected lateral regional elevation data to form a complete lateral elevation distribution map of the road surface.

[0014] Furthermore, the data processing unit is also used to identify road surface defects through image analysis, including cracks, oil stains, and areas of loose aggregate.

[0015] Furthermore, the vehicle's moving speed is limited to a range corresponding to the camera's field of view coverage and the sliding speed of the sliding seat, so that the first road image captured by the camera during the outward journey and the second road image captured during the return journey naturally overlap in the coverage area along the vehicle's forward direction.

[0016] Furthermore, the linear drive module includes a precision ball screw, a direct drive motor, and two sets of guide rails. The precision ball screw is arranged along the length of the guide rail swing mechanism, and both ends of the precision ball screw are connected to the guide rail swing mechanism through bearing seats. The output shaft of the direct drive motor is coaxially connected to one end of the precision ball screw through a coupling. The two sets of guide rails are parallel to the precision ball screw and fixed on the guide rail swing mechanism. The sliding seat is slidably connected to the guide rails through a slider.

[0017] Furthermore, the angle adjustment structure includes a housing fixed on a sliding base, a micro motor installed inside the housing, an angle feedback element for detecting and feeding back the rotation angle of the output shaft of the micro motor, and an electromagnetic locking mechanism for locking the output shaft of the micro motor; the output end of the micro motor passes through the bottom wall of the housing and is fixedly connected to the outer shell of the vision scanning unit.

[0018] Furthermore, the rotary drive module includes a servo motor with a harmonic reducer, a grating encoder, and a closed-loop control unit. The servo motor is fixed to the top of the detection beam by a mounting component. The output shaft of the servo motor is coaxially fixed to the rotating pivot shaft via a coupling structure. The grating encoder is fixed on the rotating pivot shaft and is used to acquire the swing angle of the guide rail swing mechanism in real time. The closed-loop control unit integrates a PID algorithm module, which receives the angle signal from the grating encoder and then dynamically adjusts the output current of the servo motor to control the guide rail swing mechanism to quickly switch between a first preset angle and a second preset angle and suppress angle overshoot.

[0019] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0020] 1. This invention utilizes a balancing frame system to counteract vehicle tilt caused by road bumps in real time, ensuring the detection beam remains horizontal and preventing image distortion caused by optical component attitude shifts. The visual scanning unit employs binocular vision components, combined with stereoscopic triangulation principles, to accurately calculate elevation data at various points on the road surface. Compared to the subjective interpretation errors of traditional 3-meter rulers and the benchmark offset errors of continuous surface evenness gauges, this device offers higher elevation detection accuracy without requiring manual intervention, completely eliminating the influence of subjective factors and providing reliable data support for the refined evaluation of asphalt surface evenness, depression depth, and other indicators.

[0021] 2. The guide rail swing mechanism of the present invention swings periodically between preset angles, and in conjunction with the lateral sliding of the sliding seat along the guide rail, combined with the rectangular field of view of the visual scanning unit, the lateral area of ​​the standard lane can be covered in one go without the need for multiple starts and stops to adjust the position of the vehicle body. At the same time, the matching design of the vehicle body moving speed with the field of view coverage and the speed of the sliding seat makes the images collected before and after naturally overlap, saving the complicated data stitching steps in the later stage and avoiding delays in road construction or maintenance progress due to excessive detection time.

[0022] 3. This invention adopts a pure optical detection principle, which acquires road surface images and calculates elevation data through binocular vision. The entire process does not require contact with or damage to the road surface, thus avoiding damage to the road surface structure during the detection process and saving subsequent repair costs. At the same time, the device can realize continuous detection of the entire road surface (instead of discrete sampling), which can completely capture local hidden defects of the road surface, and solve the limitations of traditional destructive detection that uses points to represent the whole surface, so as to comprehensively reflect the overall quality distribution of the road surface.

[0023] 4. The balance frame system of this invention automatically compensates for the vehicle's posture, eliminating the need for manual adjustment of the crossbeam's level. The angle adjustment structure, through a micro-motor and angle feedback element, dynamically compensates for guide rail sway, avoiding manual stop calibration. The rotary drive module and linear drive module achieve automatic speed matching and direction switching through closed-loop control, requiring no manual intervention in motion parameters. Simultaneously, a flange interface is reserved at the rear of the vehicle body, allowing for quick adaptation to existing mature lightweight electric chassis, enabling immediate use without additional modifications. The device's motion coordination and data processing logic can adjust preset parameters according to different road widths, adapting to the detection needs of various scenarios such as municipal roads and highways, reducing the equipment's usage threshold and adaptation costs.

[0024] 5. The data processing unit of this invention integrates an image-elevation data linkage analysis module. When identifying defects such as cracks, oil stains, and loose aggregates, it not only combines image features but also simultaneously retrieves the elevation data of the corresponding area. This dual feature verification reduces the defect misjudgment rate. At the same time, the data processing unit binds defect information with sliding seat displacement data, which can accurately mark the specific location of the defect in the lateral direction of the road surface. This provides a precise positioning basis for subsequent road maintenance and significantly improves the guiding value of the detection results for actual engineering decisions.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is a first-view structural schematic diagram of the present invention;

[0028] Figure 2 This is a schematic diagram of the second perspective structure of the present invention;

[0029] Figure 3 This is a first-view structural diagram of the optical detection component of the present invention;

[0030] Figure 4 This is a schematic diagram of the second-view structure of the optical detection component of the present invention;

[0031] Figure 5 This is a partial structural schematic diagram of the optical detection component of the present invention after cross-section;

[0032] Figure 6 This is a schematic diagram of the guide rail swing mechanism of the present invention at a first preset angle;

[0033] Figure 7 This is a schematic diagram of the guide rail swing mechanism of the present invention at the second preset angle.

[0034] In the picture:

[0035] 1-Car body; 2-Balance frame system; 3-Detection beam; 4-Optical detection assembly; 41-Guide rail swing mechanism; 411-Rotation fulcrum shaft; 42-Vision scanning unit; 43-Rotation drive module; 431-Servo motor; 44-Angle adjustment structure; 441-Housing; 442-Micro motor; 45-Linear drive module; 451-Precision ball screw; 452-Direct drive motor; 453-Guide rail; 454-Slider; 46-Sliding seat. Detailed Implementation

[0036] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0037] Please see Figures 1-7This invention provides a non-destructive testing device for road asphalt surface quality, comprising a vehicle body 1, a balancing frame system 2, a testing beam 3, and optical testing components 4. The testing beam 3 is mounted at the rear end of the vehicle body 1 via the balancing frame system 2. The optical testing components 4 are symmetrically arranged at the bottom of the testing beam 3, forming an integrated frame that combines mobile load-bearing, posture stability, and optical testing functions. In actual testing operations, the vehicle body 1 carries the optical testing components 4 and moves along the road to be tested. If the road surface is bumpy and causes the vehicle body 1 to tilt, the balancing frame system 2 can offset the tilt in real time, ensuring that the testing beam 3 remains horizontal at all times. This avoids the optical testing components 4 from shifting due to the tilt of the beam, ensuring accurate testing results.

[0038] As the foundation for the device's movement and load-bearing capacity, vehicle body 1 can utilize an existing, mature lightweight electric chassis. Its built-in power system can adapt to the speed requirements of road inspection and stably support the overall weight of the balancing frame system 2, the inspection beam 3, and the optical inspection components 4. A flange interface is pre-installed at the rear of vehicle body 1, allowing for rapid installation of the balancing frame system 2 without additional modifications. The balancing frame system 2 employs an existing, mature gimbal structure, which can be quickly assembled via the pre-installed flange interface on vehicle body 1. Its real-time attitude adjustment capability precisely counteracts the tilt of vehicle body 1 caused by road bumps, maintaining the level of the inspection beam 3 while providing a stable working platform for the optical inspection components 4.

[0039] In current practices of non-destructive testing of asphalt pavement quality, most devices employ fixed optical inspection components 4 (such as single cameras or single laser ranging modules). Their lateral inspection range is limited by their own field of view. To cover wider road surfaces, multiple movements of the vehicle body 1 or data splicing are required, which is not only inefficient but also prone to blind spots due to positioning deviations at the splicing points, leading to the omission of hidden defects such as minute cracks and localized dents. Therefore, this device systematically optimizes the optical inspection component 4, constructing an integrated structure where a guide rail swing mechanism 41 and a visual scanning unit 42 work collaboratively to achieve efficient, blind-spot-free inspection of wide road surfaces.

[0040] Among them, the guide rail swing mechanism 41, as the basic guiding component, is rotatably connected to the detection beam 3 through a vertically set rotating fulcrum shaft 411. Under the precise drive of the rotation drive module 43, it can periodically and smoothly swing between a first preset angle and a second preset angle, flexibly adjusting the angle between its guiding direction and the forward direction of the vehicle body 1, providing basic trajectory support for large-area lateral coverage. The visual scanning unit 42, as the core detection component, is installed on the sliding seat 46 through the angle adjustment structure 44. It can flexibly adjust the field of view angle according to the road slope or installation deviation to ensure that the detection direction is accurately aligned with the road surface, and can also slide smoothly along the guide rail swing mechanism 41 with the sliding seat 46 through the linear drive module 45. Its built-in rectangular field of view perpendicular to the forward direction of the vehicle body 1 provides a stable coverage basis for continuous acquisition of lateral area images, and can also accurately calculate the elevation data of the acquired area based on the principle of stereo vision.

[0041] The coordination between the guide rail swing mechanism 41 and the vision scanning unit 42 is the core of achieving efficient detection. When the guide rail swing mechanism 41 swings to the first preset angle or the second preset angle, its guiding direction forms a specific angle with the forward direction of the vehicle body 1. At this time, the linear drive module 45 drives the sliding seat 46 to slide along the guide rail. Through speed matching, the component speed of the sliding seat 46 in the forward direction of the vehicle body 1 is equal in magnitude and opposite in direction to the forward speed of the vehicle body 1, ensuring that the vision scanning unit 42 remains relatively stationary relative to the road surface at the moment of data acquisition. The component speed of the sliding seat 46 in the lateral direction drives the vision scanning unit 42 to move continuously. Combined with the rectangular field of view and the periodic reversal swing of the guide rail swing mechanism 41, continuous blind-spot-free coverage of the lateral area of ​​the wide road surface is finally achieved. This not only eliminates the splicing deviation and blind spot problems of traditional devices, but also improves the accuracy of detection data through precise relative static design, greatly improving the efficiency and reliability of asphalt surface quality detection.

[0042] In actual operation, after the device moves forward at a constant speed along the asphalt road surface to be tested, the rotary drive module 43 starts according to the preset program, driving the guide rail swing mechanism 41 to swing around the vertical rotation fulcrum axis 411. The swing range is strictly controlled between the first preset angle and the second preset angle. During the process, the rotary drive module 43 accurately controls the swing speed and start and stop position through the angle sensor signal fed back in real time, ensuring that the guide rail swing mechanism 41 stays stably each time it reaches the preset angle, providing a stable guide reference for the subsequent movement of the sliding seat 46.

[0043] When the guide rail swing mechanism 41 stabilizes at the first preset angle, its guiding direction forms an angle θ with the forward direction of the vehicle body 1. The linear drive module 45 calculates the required sliding speed of the sliding seat 46 along the guide rail based on the speed decomposition formula, according to the real-time forward speed of the vehicle body 1 (which can be obtained by the wheel speed sensor or GPS module of the vehicle body 1), so that the velocity component of the sliding seat 46 in the opposite direction of the forward movement of the vehicle body 1 matches the forward speed of the vehicle body 1. Under this speed control, when the visual scanning unit 42 slides along the guide rail with the sliding seat 46, it remains absolutely stationary relative to the road surface in the forward direction. At this time, the acquisition mode is activated, and the current transverse area is continuously photographed through a rectangular field of view perpendicular to the forward direction of the vehicle body 1, and the elevation data of the road surface in this area (such as smoothness, depression depth, etc.) is calculated in real time.

[0044] When the sliding seat 46 slides along the guide rail to near its limit position, the rotary drive module 43 immediately drives the guide rail swing mechanism 41 to swing in the direction of the second preset angle. At the same time, the linear drive module 45 synchronously drives the sliding seat 46 to slide in the opposite direction along the guide rail. At this time, the guide rail direction forms an angle of -θ with the forward direction of the vehicle body 1. The linear drive module 45 calculates the required speed of the sliding seat 46 again based on the forward speed of the vehicle body 1 to ensure that the visual scanning unit 42 remains relatively stationary in the forward direction when sliding in the opposite direction, and continues to acquire the current lateral area image and calculate the elevation data through the rectangular field of view.

[0045] It is worth mentioning that during the transition phase of the guide rail swing mechanism 41 swinging from the first preset angle to the second preset angle, two key movement situations occur. On the one hand, the optical detection component 4 moves forward relative to the vehicle body 1 along with the movement of the guide rail swing mechanism 41; on the other hand, since the swing process requires a certain amount of time, the vehicle body 1 will continue to move along the road surface to be detected during this period, thus forming a corresponding forward movement distance. However, this problem that may lead to scanning disconnection can be effectively solved by the design characteristics of the visual scanning unit 42. Specifically, the visual scanning unit 42 adopts a rectangular field of view. As long as the width range of the rectangular field of view is reasonably set in advance, the end area of ​​the previous scan can be connected with the starting area of ​​the next scan after the transition phase, thereby avoiding disconnection between the two scans due to double forward movement and preventing the formation of longitudinal blind spots.

[0046] In this embodiment, the visual scanning unit 42 is a binocular vision component, including two parallel image acquisition units. The optical axes of the two units are parallel and the spacing is fixed. The field of view is designed with a 30% overlap rate, jointly covering a rectangular field of view perpendicular to the forward direction of the vehicle body 1. During detection, the main controller of the device outputs a synchronous trigger signal to control the two image acquisition units to continuously acquire road surface images. After acquisition, the images are preprocessed to eliminate environmental noise and correct lens edge distortion. Then, a feature extraction algorithm is used to extract road surface feature points (such as crack edges and texture protrusions) from the two synchronous images, and a matching algorithm is used to achieve accurate matching of feature points. Subsequently, based on the principle of stereo vision triangulation, combined with the known baseline distance, lens focal length, and calculated feature point disparity, the road surface elevation data corresponding to each pixel is calculated.

[0047] To transform the collected data into complete road surface quality information, this device also includes a data processing unit. This unit establishes real-time communication with the vision scanning unit 42 and the linear drive module 45 through a data bus, and has the functions of image reception and processing, three-dimensional reconstruction calculation, displacement data association and elevation data stitching. The data processing unit first receives the binocular region image transmitted by the vision scanning unit 42. After preprocessing, it combines the disparity calculation results and completes the three-dimensional reconstruction of the local area of ​​the road surface through the principle of triangulation. The two-dimensional image pixels are converted into three-dimensional data including lateral coordinates, longitudinal coordinates (the forward direction of vehicle 1), and elevation values ​​to obtain the elevation data of the lateral region. At the same time, it receives the lateral displacement data of the sliding seat 46 fed back by the linear drive module 45 in real time. Each set of lateral region elevation data is bound to the corresponding lateral displacement coordinates of the sliding seat 46 to establish a one-to-one correspondence between the lateral position and elevation value of the road surface, so as to avoid the disconnect between the elevation data and the actual position. During continuous acquisition, the adjacent two sets of lateral region elevation data are stitched together according to the displacement increment of the sliding seat 46. Through the preset displacement overlap interval, the elevation data deviation within the overlap interval is compared to achieve a smooth transition of data and finally integrate into a complete lateral elevation distribution map of the road surface.

[0048] Furthermore, the data processing unit integrates a multi-defect-specific identification algorithm module and an image-elevation data linkage analysis module. The former constructs detection logic for the unique characteristics of cracks, oil stains, and loose aggregates, while the latter binds the defect identification results with the previously calculated road surface elevation data. Specifically, after receiving the high-definition regional image transmitted by the visual scanning unit 42, the data processing unit first performs preprocessing and simultaneously retrieves the road surface elevation data of the corresponding region as an auxiliary judgment basis. When identifying cracks, linear edges are extracted through edge detection algorithms, noise is removed through morphological operations, and target areas are screened by combining linear feature detection. If there is a significant elevation change in the region, the crack is confirmed. When identifying oil stains, the image is converted to a specific color space, suspected areas are screened, and interference is eliminated through texture contrast analysis. Oil stains are confirmed by combining elevation data (without significant fluctuations). When identifying areas with loose aggregates, texture feature parameters are calculated through texture analysis, and elevation distribution characteristics are analyzed simultaneously. Loose aggregates are confirmed when both conditions are met.

[0049] To ensure the continuity of data acquisition and stitching, the moving speed of vehicle 1 is limited to a range that matches the field-of-view coverage capability of visual scanning unit 42 and the sliding speed of sliding seat 46. This ensures that the first road image acquired by sliding seat 46 on the outward journey and the second road image acquired on the return journey naturally overlap in the coverage area along the direction of vehicle 1's movement. This design eliminates the need for additional mechanical adjustments or complex algorithm compensation, eliminating longitudinal stitching gaps caused by traditional non-overlapping methods and avoiding data redundancy caused by excessive overlap. Simultaneously, the overlapping portion can serve as a data calibration benchmark. By comparing elevation data within the area with defect identification results, local deviations caused by speed fluctuations or installation errors of sliding seat 46 can be corrected, improving the stitching accuracy of continuously acquired data.

[0050] The aforementioned coordinated motion relies on a high-precision linear drive module 45. In this embodiment, the linear drive module 45 includes a precision ball screw 451, a direct drive motor 452, and two sets of guide rails 453. The precision ball screw 451 is arranged along the length of the guide rail swing mechanism 41, and both ends of the precision ball screw 451 are connected to the guide rail swing mechanism 41 through bearing seats. The output shaft of the direct drive motor 452 is coaxially connected to one end of the precision ball screw 451 through a coupling. The two sets of guide rails 453 are parallel to the precision ball screw 451 and fixed on the guide rail swing mechanism 41. The sliding seat 46 is slidably connected to the guide rails 453 through a slider 454. During operation, the direct drive motor 452 can adjust the speed of the precision ball screw 451 in real time to match the speed of the vehicle body 1 and the change of the guide rail angle. The precision ball screw 451 ensures the accurate displacement of the sliding seat 46, while the two sets of guide rails 453 constrain the movement of the sliding seat 46 to prevent it from moving around, providing reliable motion support for the vision scanning unit 42 to continuously and accurately acquire images.

[0051] To prevent the visual scanning unit 42's field of view from tilting when the guide rail swings, in this embodiment, the angle adjustment structure 44 includes a housing 441 fixed on a sliding seat 46, a micro motor 442 installed inside the housing 441, an angle feedback element (not shown) for detecting and feeding back the rotation angle of the output shaft of the micro motor 442, and an electromagnetic locking mechanism (not shown) for locking the output shaft of the micro motor 442. The output end of the micro motor 442 passes through the bottom wall of the housing 441 and is fixedly connected to the outer shell of the visual scanning unit 42. When the guide rail swing mechanism 41 deflects to a first preset angle or a second preset angle, the angle feedback element collects the guide rail deflection angle signal in real time and transmits it to the control unit. The control unit drives the micro motor 442 to start through a preset compensation algorithm, causing the visual scanning unit 42 to rotate in the opposite direction by the same angle, ensuring that its rectangular field of view is always perpendicular to the road surface. After the angle is adjusted to the correct position, the electromagnetic locking mechanism immediately locks the motor output shaft to resist vehicle bumps and vibrations. Combined with the protective design of the housing 441, this ensures that the visual scanning unit 42 can continuously acquire high-quality images.

[0052] Precise control of the guide rail swing is achieved by the rotary drive module 43. In this embodiment, the rotary drive module 43 includes a servo motor 431 with a harmonic reducer, a grating encoder (not shown), and a closed-loop control unit (not shown). The servo motor 431 is fixed to the top of the detection beam 3 by a mounting component, and the output shaft of the servo motor 431 is coaxially fixed to the rotation fulcrum shaft 411 through a coupling structure. The grating encoder is fixed on the rotation fulcrum shaft 411 to collect the swing angle of the guide rail swing mechanism 41 in real time. The closed-loop control unit integrates a PID algorithm module. When it is necessary to drive the guide rail swing mechanism 41 to switch between a first preset angle and a second preset angle, the closed-loop control unit receives the target angle command, and at the same time, the grating encoder feeds back the current angle signal in real time. The closed-loop control unit calculates the deviation through the PID algorithm and outputs a current adjustment signal to dynamically adjust the operating state of the servo motor 431, ensuring that the guide rail swing mechanism 41 switches quickly and without angle overshoot, providing a stable motion reference for the visual scanning unit 42, and further ensuring the image acquisition quality and the accuracy of elevation data calculation.

[0053] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A non-destructive testing device for quality of road asphalt pavement, comprising a vehicle body, a testing beam mounted on the rear end of the vehicle body through a balance frame system, and optical testing assemblies symmetrically mounted on the bottom of the testing beam, characterized in that, The optical detection assembly comprises: a guide rail swing mechanism, which is rotationally connected with the detection beam through a vertically arranged rotation fulcrum shaft and can be periodically swung between a first preset angle and a second preset angle by a rotation driving module; a visual scanning unit, which is mounted on a sliding seat through an angle adjusting structure, the sliding seat being slidably arranged on the guide rail swing mechanism through a linear driving module, the visual scanning unit having a rectangular field of view perpendicular to the advancing direction of the vehicle body, for continuously collecting images of a lateral region of the road surface and calculating elevation data of the region based on the principle of stereovision; wherein the rotation driving module and the linear driving module are linked and matched, when the guide rail swing mechanism swings to the first preset angle or the second preset angle, the guide rail swing mechanism forms a specific included angle with the advancing direction of the vehicle body, so that when the linear driving module drives the sliding seat to slide along the guide rail, the sliding speed of the sliding seat in the advancing direction of the vehicle body is equal in magnitude and opposite in direction to the advancing speed of the vehicle body, so that the visual scanning unit keeps relatively static in the advancing direction of the vehicle body at the moment of data collection, and the visual scanning unit is continuously covered and collected by the sliding speed of the sliding seat in the lateral direction.

2. The device for non-destructive testing of the quality of a road asphalt surface layer according to claim 1, characterized in that, The visual scanning unit is a binocular vision assembly, which comprises two image collecting units arranged in parallel, the optical axes of the two image collecting units being kept parallel and fixed in distance, and collectively covering the rectangular field of view, and the elevation data of the road surface are obtained through parallax calculation.

3. The device for non-destructive testing of the quality of a road asphalt surface layer according to claim 1, characterized in that, Further comprising a data processing unit, which is used for receiving the region images collected by the visual scanning unit, and performing three-dimensional reconstruction on the region images to calculate the elevation data of each point of the road surface, and simultaneously combining the lateral displacement data of the sliding seat to splice the continuously collected lateral region elevation data to form a complete lateral elevation distribution map of the road surface.

4. The device for non-destructive testing of the quality of a road asphalt surface layer according to claim 3, characterized in that, The data processing unit is further used for identifying road surface defects through image analysis, the road surface defects including cracks, oil stains and loose aggregate areas.

5. The device for non-destructive testing of the quality of a road asphalt surface layer according to claim 1, characterized in that, The moving speed of the vehicle body is limited in a range corresponding to the coverage capability of the camera field of view and the sliding speed of the sliding seat, so that a first road image collected by the camera when the sliding seat goes and a second road image collected by the camera when the sliding seat returns naturally form an overlapping part in the coverage region along the advancing direction of the vehicle body.

6. The device for non-destructive testing of quality of road asphalt pavement according to claim 1, characterized in that, The linear driving module comprises a precision ball screw, a direct drive motor and two sets of guide rails, the precision ball screw being arranged along the length direction of the guide rail swing mechanism, and the two ends of the precision ball screw being connected with the guide rail swing mechanism through bearing seats, the output shaft of the direct drive motor being coaxially connected with one end of the precision ball screw through a shaft coupling, the two sets of guide rails being parallel to the precision ball screw and fixed on the guide rail swing mechanism, and the sliding seat being slidably connected with the guide rails through a sliding block.

7. The device for non-destructive testing of quality of road asphalt pavement according to claim 1, characterized in that, The angle adjusting structure comprises a machine shell fixed on the sliding seat, a micro motor mounted in the machine shell, an angle feedback element for detecting and feeding back the rotation angle of the output shaft of the micro motor, and an electromagnetic locking mechanism for locking the output shaft of the micro motor; the output end of the micro motor penetrates through the bottom wall of the machine shell and is fixedly connected with the shell of the visual scanning unit.

8. The device for non-destructive testing of quality of road asphalt pavement according to claim 1, characterized in that, The rotation driving module comprises a servo motor with a harmonic reducer, a grating encoder and a closed-loop control unit, the servo motor is fixed on the top of the detection beam through a mounting piece, the output shaft of the servo motor is coaxially fixedly connected with the rotation fulcrum shaft through a shaft connection structure, the grating encoder is fixed on the rotation fulcrum shaft and is used for collecting the swing angle of the guide rail swing mechanism in real time, the closed-loop control unit integrates a PID algorithm module, after receiving the angle signal of the grating encoder, the closed-loop control unit controls the guide rail swing mechanism to rapidly switch between the first preset angle and the second preset angle and suppresses the angle overshoot through dynamically adjusting the output current of the servo motor.

Images