Measuring and monitoring system for high-speed construction

Abstract

The invention belongs to the technical field of monitoring systems, and particularly relates to a measuring and monitoring system for high-speed construction, which comprises a walking module, and a three-dimensional scanning module, a vehicle pose monitoring module and a control module which are arranged on the walking module, the walking module, the three-dimensional scanning module and the pose monitoring module are electrically connected with the control module and controlled by the control module, and pose changes of a vehicle provided with a three-dimensional laser scanner are monitored through the pose monitoring module and transmitted to a compensation unit of the control module. And the compensation unit processes the pose change data and performs geometric transformation, so that correction of the point cloud data uploaded by the three-dimensional laser scanner is realized, point cloud data deviation caused by vehicle pose change can be effectively eliminated, and subsequent monitoring of the flatness of the asphalt pavement in construction according to the point cloud data is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of monitoring systems, and in particular relates to a measurement monitoring system for high-speed construction. Background Art

[0002] In recent years, with the increasing requirements for construction accuracy and the development of intelligence, laser scanning technology has been widely used in construction measurements that require high precision due to its non-contact and fast measurement characteristics. In particular, in the construction of highway pavements with high requirements for the flatness of asphalt paving, it is necessary to accurately calculate the flatness of the paved road surface after the asphalt paving is completed, and then adjust the places that need to be adjusted according to the flatness of the road surface until it meets the acceptance standards.

[0003] However, the existing laser scanning measurement devices usually install the laser scanner on the moving vehicle, and perform laser scanning on the road surface during the driving process of the car to obtain the point cloud data of the road surface. For example, the publication number is: CN114001678A, a road surface flatness detection method, device and vehicle based on vehicle-mounted laser radar, which discloses a method for detecting the flatness of the road surface using a vehicle-mounted laser radar. Another example is: CN216474919U, a real-time detection system for roadbed compaction based on 5G technology.

[0004] However, the vehicle (or driving device) will pitch or tilt during driving. For example, when the vehicle is driving at a corner, the body will tilt, causing the scanning plane of the laser scanner installed on the body to no longer remain parallel to the road surface, resulting in tilt errors in the scan data. When the vehicle is driving on an uphill or downhill section, the height of the front and rear axles of the vehicle will change, and the vertical direction of the laser scanner will also change, resulting in longitudinal errors in the scan data.

[0005] In addition, since the subsequent processing of point cloud data includes sampling after fitting according to the scanned data, during the fitting process, the least square method or other plane fitting algorithms are generally used to fit an optimal plane, which is used as the reference plane of the road surface to evaluate the flatness of the road surface. However, due to changes in the vehicle's posture, the vehicle itself will pitch (changes in the height of the front and rear axles) and tilt (changes in the height of the left and right axles). These posture changes will cause the scanning plane of the laser scanner to no longer remain parallel to the road surface, resulting in systematic elevation deviations in the point cloud data, resulting in the subsequent plane fitted based on the point cloud data being unable to accurately reflect the actual flatness of the road surface.

[0006] Therefore, there is a need for a method of using a 3D laser scanner to obtain point cloud data of the road surface to measure the flatness of the road surface during construction, and to compensate the scanning data of the 3D laser scanner according to the posture changes of the vehicle on which the 3D laser scanner is installed to improve the accuracy of detection. Summary of the invention

[0007] In order to solve the above problems existing in the prior art, the present invention provides a high-speed construction measurement and monitoring system to solve the problem that the three-dimensional laser scanner installed on the vehicle may cause deviation in the point cloud data acquired due to the change in the vehicle's posture.

[0008] The object of the present invention can be achieved by the following technical solutions: A high-speed construction measurement and monitoring system, comprising a walking module and a three-dimensional scanning module, a vehicle posture monitoring module and a control module arranged on the walking module, wherein the walking module, the three-dimensional scanning module and the posture monitoring module are respectively electrically connected to the control module and are controlled by the control module;

[0009] The posture monitoring module is used to monitor the posture change data of the walking module and transmit it to the control module, wherein the posture change includes the pitch angle and the tilt angle of the walking module;

[0010] The three-dimensional scanning module is used to obtain point cloud data of the road surface and upload the point cloud data to the control module;

[0011] The control module includes a calculation unit and a compensation unit, wherein the compensation unit performs calculation and analysis according to the pitch angle and the tilt angle of the walking module to compensate and correct the point cloud data and transmits the corrected point cloud data to the calculation unit;

[0012] The calculation unit evaluates the smoothness of the asphalt road surface according to the corrected point cloud data.

[0013] Preferably, the posture monitoring module includes an acceleration measurement device and an angular velocity measurement device:

[0014] The acceleration measuring device is used to measure the acceleration of the walking module;

[0015] The angular velocity measuring device is used to measure the angular velocity of the walking module;

[0016] The acceleration measuring device and the angular velocity measuring device are electrically connected to the control module respectively and transmit monitoring data.

[0017] Preferably, it also includes a network module, and the walking module, three-dimensional scanning module, posture monitoring module and control module communicate with each other under the network module. The network module adopts a synchronous time protocol to transmit data and signals, and the data signals uploaded by the posture monitoring module and the three-dimensional scanning module are all timestamped.

[0018] Preferably, a pitch angle threshold and a tilt angle threshold are provided in the control module;

[0019] The analysis unit receives and analyzes the vehicle's posture change data uploaded by the IMU in real time. The analysis unit is set with three abnormal conditions, abnormal condition one: the pitch angle is greater than the pitch angle threshold, abnormal condition two: the tilt angle is greater than the tilt angle threshold, and abnormal condition three: the pitch angle is greater than the pitch angle threshold and the tilt angle is greater than the tilt angle threshold. The analysis module compensates and corrects the original point cloud data that meets one of the above three abnormal conditions based on the data uploaded by the IMU, and the calculation unit evaluates the flatness of the road surface based on the point cloud data after compensation and correction.

[0020] Preferably, the control module further includes a storage unit, and the storage unit includes two sub-storage units, and the two sub-storage units respectively store the data transmitted by the three-dimensional scanning module and the posture monitoring module.

[0021] Preferably, a positioning unit is provided on the walking module, and the positioning unit is electrically connected to the control module and transmits the positioning information of the walking module to the control module.

[0022] Preferably, the three-dimensional scanning module includes at least two scanning surfaces arranged in front of the walking direction of the walking module;

[0023] The compensation module combines the point cloud data scanned by at least two scanning surfaces and generates a set of combined point cloud data after deduplication. The compensation module uses the set of combined point cloud data for subsequent compensation correction.

[0024] The beneficial effects of the present invention are:

[0025] The IMU monitors the posture changes of the vehicle equipped with a 3D laser scanner and transmits them to the compensation unit of the control module. The compensation unit processes the posture change data and performs geometric transformation to correct the point cloud data uploaded by the 3D laser scanner. This can effectively eliminate the point cloud data deviation caused by the vehicle posture change and improve the subsequent monitoring of the flatness of the asphalt pavement during construction based on the point cloud data.

[0026] Subsequently, the vehicle's posture change data uploaded by the IMU is screened in advance through the set pitch angle threshold and tilt angle threshold, so that the control module can not only capture the vehicle's posture changes whose change amplitude exceeds the set threshold, but also realize compensation processing of subsequent point cloud data, realize targeted processing of the vehicle's posture changes, realize precise calculation, and at the same time reduce the system's computing power while ensuring measurement accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0028] Figure 1It is a system block diagram of the present invention. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0030] See also Figure 1 , this embodiment provides a high-speed construction measurement and monitoring system, including a walking module and a three-dimensional scanning module, a vehicle posture monitoring module and a control module arranged on the walking module, wherein the walking module, the three-dimensional scanning module and the posture monitoring module are respectively electrically connected to the control module and are controlled by the control module;

[0031] The control module includes a calculation unit and a compensation unit. The compensation unit performs calculation and analysis according to the pitch angle and tilt angle of the walking module to compensate and correct the point cloud data and transmit the corrected point cloud data to the calculation unit.

[0032] The calculation unit evaluates the flatness of the road surface during the construction of the airport expressway according to the corrected point cloud data corrected by the compensation unit. The calculation unit can determine the road surface reference line of the road surface by processing the corrected point cloud data after the compensation unit compensates the original point cloud data. The road surface reference line is equivalent to a virtual three-meter ruler. The virtual three-meter ruler is used to estimate the flatness of the road surface. The calculation unit can determine the flatness of the road surface according to the road surface reference line and the above point cloud data. The control module sends the result to the processor of the subsequent construction steps, such as a paver with intelligent functions. By giving the paver the flatness data of the road surface, the paver adjusts the subsequent construction parameters according to the flatness data.

[0033] The walking module uses a moving vehicle or a moving device with navigation and control functions to drive the three-dimensional laser scanning module to move and scan the road surface. The three-dimensional laser scanning module enables the three-dimensional laser radar to perform measurements. The three-dimensional laser radar is set on the vehicle. When the vehicle is running, the laser radar can detect the original point cloud data on the road surface, and the three-dimensional laser scanner transmits the scanned data to the control module. Specifically, the scanning lines emitted by the laser radar form multiple intersections with the road surface, and the multiple intersections are processed to obtain corresponding point cloud data, and the point cloud data is transmitted to the control module. A positioning unit is set on the vehicle, and the positioning unit is electrically connected to the control module and transmits the positioning information of the walking module to the control module. The positioning unit on the vehicle can be a positioning unit of the vehicle's own positioning system, or it can be a separately set positioning device, which can realize accurate detection of the moving vehicle, so as to facilitate the subsequent control module to calculate the flatness of the road surface.

[0034] As the vehicle (or the driving device) is driving, it may pitch or tilt. For example, when the vehicle is turning, the vehicle body may tilt, causing the scanning plane of the laser scanner installed on the vehicle body to no longer remain parallel to the road surface, resulting in a tilt error in the scanning data. When the vehicle is driving on an uphill or downhill section, the height of the front and rear axles of the vehicle will change, and the vertical direction of the laser scanner will also change accordingly, resulting in a longitudinal error in the scanning data, which in turn causes the subsequent control module to process the three-dimensional scanning data. The posture monitoring module is used to monitor the posture change data of the walking module and transmit it to the control module. The posture change includes the pitch angle, tilt angle and azimuth angle of the walking module;

[0035] The posture monitoring module is implemented through a combination of high-precision sensors, such as IMU, to monitor the vehicle's posture changes in real time, including pitch angle, tilt angle and azimuth angle. These sensors can provide high-frequency and high-precision posture data to ensure that the posture monitoring module can capture subtle posture changes of the vehicle in a timely manner.

[0036] IMU is the abbreviation of inertial measurement unit. IMU includes an acceleration measurement device, an angular velocity measurement device and a magnetometer. The acceleration measurement device and the angular velocity measurement device respectively measure the acceleration and angular velocity of a moving vehicle in real time and transmit the measurement results to the control module. Of course, IMU is an integral unit. The azimuth, pitch angle and tilt angle of the vehicle are calculated through the IMU's own built-in algorithm. IMU processes the monitoring results and transmits them to the control module.

[0037] The compensation unit in the control module then corrects the original point cloud data uploaded by the 3D laser scanner according to the change in the vehicle's posture uploaded by the IMU. The compensation unit converts the original point cloud data collected by the 3D laser scanner from the scanner coordinate system to the world coordinate system based on the posture information provided by the IMU. The compensation unit can first try to use quaternions to represent the rotation relationship in three dimensions, and fuse the IMU data through the Kalman Filter to improve the accuracy of vehicle posture estimation.

[0038] The processing unit performs geometric transformation on the original point cloud data. The specific transformation steps include:

[0039] Rotation matrix: The rotation matrix is ​​constructed based on the real-time pitch angle, tilt angle and azimuth angle of the vehicle transmitted by the IMU. It is used to describe the rotation relationship of the 3D scanner coordinate system relative to the world coordinate system to achieve geometric transformation of coordinates in three dimensions:

[0040] The coordinates of the original point cloud data are set to (x, y, z), and the compensation matrix calculated by the compensation unit according to the pitch angle and tilt angle transmitted by the IMU is set to R. The coordinates of the point cloud data after compensation by the compensation unit are set to (x1, y1, z1) = R × (x, y, z). The algorithm of the compensation matrix can first set a single-axis rotation matrix according to the rotation angle, tilt angle and azimuth angle, and then perform matrix multiplication on the three single-axis rotation matrices of the same point to obtain the final rotation matrix R. The rotation method between the three single-axis rotation matrices can be selected as needed. You can choose to rotate around the Z axis first, then around the Y axis, and finally around the X axis. The three single-axis rotation matrices calculated to achieve the rotation angle, tilt angle and azimuth angle can represent the rotation relationship of the x, y, and z axes of the vehicle at that time point, and then the combined rotation matrix R can compensate for that time point.

[0041] The IMU monitors the posture changes of the vehicle equipped with a 3D laser scanner and transmits them to the compensation unit of the control module. The compensation unit processes the posture change data and performs geometric transformation to correct the point cloud data uploaded by the 3D laser scanner. This can effectively eliminate the point cloud data deviation caused by the vehicle posture change and improve the subsequent monitoring of the flatness of the asphalt pavement during construction based on the point cloud data.

[0042] Since there may be a time difference between the IMU's monitoring data of the vehicle's posture and the point cloud data scanned by the 3D laser scanner, and since the vehicle's position changes in real time during the driving process, and the subsequent compensation unit needs to compensate the 3D laser scanning data according to the data uploaded by the IMU at the same time node, in order to facilitate the convenience and accuracy of subsequent data processing, a network module is also included. The walking module, the 3D scanning module, the posture monitoring module and the control module communicate under the network module, that is, the vehicle, the 3D laser scanner and the control module communicate in the same transmission network through the set network module to ensure that the data transmitted from the vehicle and the 3D laser scanner to the control module is synchronized, which is convenient for subsequent data processing. And a synchronous time protocol such as the NTP protocol is used in the transmission network to transmit data and signals, further improving the accuracy of data synchronization. The data signals uploaded by the posture monitoring module and the 3D scanning module are all timestamped. When collecting data, the 3D laser scanner and the IMU add timestamps to their data formats. The timestamp should be based on the clock of the transmission network, and under the guarantee of the synchronous time protocol, ensure that the timestamps of the 3D laser scanner and IMU are consistent at the same time, so that the data can be aligned when the subsequent compensation module processes the data. If a certain data is lost or delayed, the network module can estimate the missing data through the interpolation algorithm. The compensation module uses the posture change data to compensate and correct the point cloud data with the same timestamp as the posture change data.

[0043] Since there are many time nodes for the 3D data uploaded by the 3D laser scanner, the data received and processed by the control module is extremely large, so it is necessary to classify the data. In this embodiment, the control module also includes a storage unit, which includes two sub-storage units. The two sub-storage units store the data transmitted by the 3D laser scanner and the IMU respectively. Since the data uploaded by the 3D scanner and the IMU are both timestamped, the data with the timestamp at the time node can be stored in two categories according to a certain time node. One category is the classification of the 3D laser scanner and the IMU. The first and second categories here are named after the classification method of the data. The first category indicates that the data is divided into the point cloud data of the 3D laser scanning and the monitoring data of the IMU. The second category is the classification by time period in the point cloud data, which is convenient for the subsequent data retrieval and retrospective inspection.

[0044] Due to the changes in different driving environments during the driving process, the change amplitude of the vehicle's posture varies greatly, and slight fluctuations in posture change will not have a significant impact on the measurement results. Therefore, in order to reduce the amount of calculation, it is necessary to set a starting value, which indicates that the amplitude of the vehicle's posture change reaches a certain level. When the amplitude of the vehicle's posture change reaches a certain level, the compensation unit uses the vehicle posture change in this time period to compensate the data of the corresponding time period in the original point cloud data. Therefore, in one embodiment, the control module also includes an analysis unit, and a pitch angle threshold and a tilt angle threshold are set in the analysis unit.

[0045] The analysis unit receives and analyzes the vehicle's posture change data uploaded by the IMU in real time. The analysis unit is set with three conditions, namely, condition one: the pitch angle is greater than the pitch angle threshold, condition two: the tilt angle is greater than the tilt angle threshold, and condition three: the pitch angle is greater than the pitch angle threshold and the tilt angle is greater than the tilt angle threshold. The analysis module compensates the point cloud data that meets at least one of the above three conditions in the data uploaded by the IMU, that is, the data of the time period or time node is compensated and then replaced with the point cloud data scanned by the three-dimensional laser scanner of the time period or time node. The calculation unit evaluates the flatness of the road surface based on the compensated point cloud data.

[0046] Regarding the design of the inclination angle threshold, pitch angle threshold or azimuth angle threshold, different construction environments have different requirements for road surface flatness. Therefore, the threshold should be adjusted according to the specific construction scenario and analyzed in combination with previous point cloud data. For example, in highway road construction, there are slight differences in the road surface flatness acceptance requirements in different regions for the specific flatness requirements on the highway. The maximum change values ​​of the inclination angle and pitch angle calculated in reverse under the flatness are analyzed. That is, when the vehicle's inclination angle and pitch angle reach the maximum change value, the data scanned by the 3D laser scanner installed on the vehicle will be deviated, and this value is set as the threshold here.

[0047] By analyzing the pitch angle threshold and tilt angle threshold set by the unit to screen the vehicle's posture change data uploaded by the IMU in advance, the control module can not only capture the vehicle's posture change when the change amplitude exceeds the set threshold, and then realize compensation processing for subsequent point cloud data, but also compensate for the corresponding segments in the original point cloud data, thereby realizing targeted processing of data and reducing the system's computing power.

[0048] In actual construction scenarios, when scanning the road surface with a 3D laser scanner, it is necessary to remove obstacles on the road surface as much as possible so that the scanned data can correctly reflect the changes in the flatness of the road surface.

[0049] However, when the laser beam emitted by the three-dimensional laser scanner encounters a raised structure on the road surface, the object may block the area behind it, making it impossible for the laser beam to reach these areas. For example, if there is a depression on the scanned road surface, the pit wall of the depression may block the laser beam, resulting in the area inside the depression being unable to be scanned, and the three-dimensional laser scanner relies on the laser beam to be reflected back to the sensor set inside it to obtain the scanning distance, and estimate the unevenness of the road surface based on the scanning distance. If the laser beam is incident on the uneven surface at a large angle, the reflected light may deviate from the receiving range of the sensor, resulting in data loss in the area. This situation is particularly evident when the vehicle is going uphill or downhill. In actual construction scenarios, in order to ensure that the scanning surface of the three-dimensional laser scanner can completely cover the entire construction road surface, in one embodiment, the three-dimensional scanning module includes at least two scanning surfaces arranged directly in front of the walking direction of the walking module;

[0050] The compensation module combines the point cloud data scanned by at least two scanning surfaces and removes duplicate data to generate a combined point cloud data. The compensation module uses the combined point cloud data for subsequent compensation correction.

[0051] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-speed construction measurement and monitoring system, characterized in that: It includes a walking module and a three-dimensional scanning module, a vehicle posture monitoring module and a control module arranged on the walking module, wherein the walking module, the three-dimensional scanning module and the posture monitoring module are electrically connected to the control module respectively and are controlled by the control module; The posture monitoring module is used to monitor the posture change data of the walking module and transmit it to the control module, wherein the posture change includes the pitch angle and the tilt angle of the walking module; The three-dimensional scanning module is used to obtain original point cloud data of the road surface and upload the original point cloud data to the control module; The control module includes a calculation unit and a compensation unit, wherein the compensation unit performs calculation and analysis according to the pitch angle and the tilt angle of the walking module to compensate and correct the original point cloud data and transmit the corrected point cloud data to the calculation unit; The calculation unit evaluates the smoothness of the asphalt road surface according to the corrected point cloud data.

2. A high-speed construction measurement and monitoring system according to claim 1, characterized in that: The posture monitoring module includes an acceleration measurement device and an angular velocity measurement device: The acceleration measuring device is used to measure the acceleration of the walking module; The angular velocity measuring device is used to measure the angular velocity of the walking module; The acceleration measuring device and the angular velocity measuring device are electrically connected to the control module respectively and transmit monitoring data.

3. A high-speed construction measurement and monitoring system according to claim 2, characterized in that: It also includes a network module. The walking module, three-dimensional scanning module, posture monitoring module and control module communicate with each other under the network module. The network module adopts a synchronous time protocol to transmit data and signals. The data signals uploaded by the posture monitoring module and the three-dimensional scanning module are all timestamped.

4. A high-speed construction measurement and monitoring system according to claim 3, characterized in that: The compensation module uses the posture change data to compensate and correct the point cloud data with the same timestamp as the posture change data.

5. A high-speed construction measurement and monitoring system according to claim 4, characterized in that: The control module is provided with a pitch angle threshold and a tilt angle threshold; The analysis unit receives and analyzes the vehicle's posture change data uploaded by the IMU in real time. The analysis unit is set with three abnormal conditions, abnormal condition one: the pitch angle is greater than the pitch angle threshold, abnormal condition two: the tilt angle is greater than the tilt angle threshold, and abnormal condition three: the pitch angle is greater than the pitch angle threshold and the tilt angle is greater than the tilt angle threshold. The analysis module compensates and corrects the original point cloud data that meets one of the above three abnormal conditions based on the data uploaded by the IMU, and the calculation unit evaluates the flatness of the road surface based on the point cloud data after compensation and correction.

6. A high-speed construction measurement and monitoring system according to claim 3, characterized in that: The control module also includes a storage unit, which includes two sub-storage units. The two sub-storage units respectively store data transmitted by the three-dimensional scanning module and the posture monitoring module.

7. The high-speed construction measurement and monitoring system according to claim 1, characterized in that: The walking module is provided with a positioning unit, which is electrically connected to the control module and transmits the positioning information of the walking module to the control module.

8. The high-speed construction measurement and monitoring system according to claim 1, characterized in that: The three-dimensional scanning module includes at least two scanning surfaces arranged in front of the walking direction of the walking module; The compensation module combines the original point cloud data scanned by at least two scanning surfaces and generates a set of combined point cloud data after deduplication. The compensation module uses the set of combined point cloud data for subsequent compensation correction.

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