In-situ metrological calibration method and device for high dynamic deflection measuring instrument

Abstract

The application provides a high-dynamic deflection measuring instrument in-situ metrological calibration method and device, which comprises the following steps: obtaining the road surface transverse deformation data at each sampling time point in the process of the high-dynamic deflection measuring device entering and leaving the target measuring area through the high-dynamic deflection measuring device erected in the target measuring area; obtaining the dynamic deflection measurement value at each sampling time point in the process of the high-dynamic deflection measuring device entering and leaving the target measuring area; taking the road surface transverse deformation data and the original road surface deflection measurement data at the key time points respectively; and performing metrological calibration on the original road surface deflection measurement data at the key time points based on the road surface transverse deformation data at the key time points. The original road surface deflection measurement data is calibrated by the deflection measurement data with higher precision, the calibrated road surface deflection measurement data is more accurate, and the reliability of the detection result of the high-dynamic deflection measuring device is improved.

Description

Technical Field

[0001] This invention relates to the field of road non-destructive testing technology, and in particular to an in-situ metrological calibration method and device for a high dynamic deflection measuring instrument. Background Technology

[0002] Currently, laser dynamic deflection detection technology enables rapid detection of road surface deflection at normal traffic speeds, and related technologies have been commercialized and applied (LDD, TSD). Regarding the calibration of laser dynamic deflection systems, some researchers have calibrated the installation angle of the Doppler sensor fixed on the crossbeam by moving the crossbeam, consistent with the cancellation method used by ARRB. However, this method requires additional space for the crossbeam to move, resulting in a longer TSD vehicle body and certain limitations.

[0003] Some research companies have proposed calibration methods based on parallel laser beams to calibrate the installation angle difference of the Doppler sensor within the LDD. Other scholars have proposed obtaining the Doppler sensor installation angle through static calibration. However, these methods differ significantly from actual road detection scenarios, and the equipment status during calibration differs markedly from normal driving conditions; none of these methods achieve direct and unified calibration of dynamic deflection values.

[0004] Although dynamic deflection measurement technology has made remarkable progress and been widely applied, there are still problems in the precise measurement of pavement dynamic deformation, the unification of high dynamic deflection values, and calibration traceability. Therefore, there is an urgent need for a method for in-situ metrological calibration of high dynamic deflection measurement analyzers. Summary of the Invention

[0005] This invention provides an in-situ metrological calibration method and device for a high dynamic deflection measuring instrument, which addresses the lack of a unified calibration method for dynamic deflection values ​​in the prior art. It realizes an in-situ metrological calibration method and device for a high dynamic deflection measuring and analyzing instrument, further improving the reliability of the detection results of the dynamic deflection measurement system and meeting the important needs of road structure performance evaluation and disaster early warning under high dynamic loads.

[0006] This invention provides an in-situ metrological calibration method for a high dynamic deflection measuring instrument, comprising: The road lateral deformation data at each sampling moment during the process from before the high dynamic deflection measuring device enters the target test area to when it leaves the target test area are obtained by the high dynamic deflection measuring device installed in the target test area, and this data is used as the road lateral deformation dataset. The dynamic deflection measurement value is obtained at each sampling moment during the process of entering and leaving the target measurement area by the high dynamic deflection measurement device, which is used as the original pavement deflection measurement dataset. The key moments are extracted from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively. The key moments represent the moments when the load center of the high dynamic deflection measurement device moves to the point where it is aligned with the preset measurement unit in the high dynamic deflection measurement device along the driving direction. Based on the lateral deformation data of the road surface at key moments, the original road surface deflection measurement data at key moments are calibrated to obtain calibrated road surface deflection measurement data.

[0007] The in-situ metrological calibration method for a high dynamic deflection measuring instrument provided by the present invention further includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Based on the abrupt change times in the set of road lateral deformation time series data, determine the key time periods when the load wheel corresponding to the load center enters and leaves the preset measurement unit; The midpoint of the critical time period is taken as the critical moment.

[0008] According to the in-situ calibration method of a high-dynamic deflection measuring instrument provided by the present invention, the high-dynamic deflection measuring device is equipped with a high-frequency signal generator, and both the high-dynamic deflection measuring device and the high-dynamic deflection measuring device are equipped with a receiving device matched to the high-frequency signal generator. The step of extracting key moment original pavement deflection measurement data from the original pavement deflection measurement dataset specifically includes: Determine a first mapping relationship between the road lateral deformation data acquisition time of the high dynamic deflection metering device and the signal reception time of the receiving device installed on it; Determine a second mapping relationship between the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device and the signal reception time of the receiving device installed on it; Based on the first and second mapping relationships, the associated time corresponding to the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device is determined. The data of the associated time are extracted from the original pavement deflection measurement dataset as the original pavement deflection measurement data corresponding to the key time.

[0009] According to the in-situ calibration method for a high dynamic deflection measuring instrument provided by the present invention, the step of calibrating the original pavement deflection measurement data at the key moment based on the pavement lateral deformation data at the key moment specifically includes: Extract the deformation data at a preset longitudinal position from the road surface transverse deformation data to obtain the road surface longitudinal deformation measurement data; The original pavement deflection measurement data are calibrated based on the pavement longitudinal deformation measurement data. The preset longitudinal position is determined based on the distance between the high dynamic deflection measuring device and the high dynamic deflection metering device along the road width at the critical moment.

[0010] The in-situ metrological calibration method for a high dynamic deflection measuring instrument provided by the present invention further includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Determine the location of data abrupt changes in the time series data of the road surface lateral deformation; Determine the first distance between the location where the data mutation occurs and the measurement unit corresponding to the road surface lateral deformation time series data; The preset longitudinal position is determined based on the first distance.

[0011] The in-situ metrological calibration method for a high dynamic deflection measuring instrument provided by the present invention further includes: Acquire longitudinal deformation measurement data of the road surface under various preset road structures and different preset measurement speeds, and obtain the original road surface deflection measurement data that matches them; Using numerical analysis, calibration models for each preset road structure were established for all measuring points of the high dynamic deflection measuring device.

[0012] According to the present invention, the installation position of each measuring unit in the high dynamic deflection measuring device is determined according to the relative installation position of the deflection basin measuring point of the corresponding measuring unit in the high dynamic deflection measuring device, so that at critical moments, each measuring point in the high dynamic deflection measuring device has one and only one measuring line projected by the measuring unit of the corresponding high dynamic deflection measuring device.

[0013] According to the present invention, a method for in-situ calibration of a high dynamic deflection measuring instrument is provided, wherein a safety distance sensor is installed on the side of the high dynamic deflection measuring device facing the direction of travel of the high dynamic deflection measuring device, for detecting the real-time distance between the sensor and the high dynamic deflection measuring device along the road width direction. If the real-time distance is less than a preset safety threshold, a safety warning is issued for the high dynamic deflection measuring device.

[0014] According to the in-situ calibration method of a high dynamic deflection measuring instrument provided by the present invention, at the critical moment, the support point of the measuring unit used to set up the high dynamic deflection measuring device is located outside the road surface deformation zone.

[0015] The present invention also provides an in-situ metrological calibration device for a high dynamic deflection measuring instrument, comprising: The measurement data acquisition module is used to acquire road lateral deformation data at each sampling moment during the process from the time the high dynamic deflection measuring device enters the target measurement area to the time it leaves the target measurement area, using the high dynamic deflection measuring device installed in the target measurement area, as the road lateral deformation dataset. The raw data acquisition module is used to acquire the dynamic deflection measurement values ​​at each sampling moment during the process of the high dynamic deflection measurement device entering and leaving the target measurement area, as the raw pavement deflection measurement dataset. The key data matching module is used to extract key moment lateral deformation data and original pavement deflection measurement data from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively. The key moment represents the moment when the load center of the high dynamic deflection measuring device moves to be aligned with the preset measuring unit in the high dynamic deflection measuring device along the driving direction. The calibration data determination module is used to perform metrological calibration on the original pavement deflection measurement data based on the pavement lateral deformation data to obtain calibrated pavement deflection measurement data.

[0016] The in-situ metrological calibration method and device for high dynamic deflection measuring instrument provided by this invention obtains deflection measurement data and original pavement deflection measurement data of the same target measurement area at the same critical moment through a high dynamic deflection metering device and a high dynamic deflection measuring device. The original pavement deflection measurement data is calibrated by the higher-precision deflection measurement data, resulting in more accurate calibrated pavement deflection measurement data and improving the reliability of the detection results of the high dynamic deflection measuring device. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the in-situ metrological calibration method for the high dynamic deflection measuring instrument provided by the present invention. Figure 2 This is a schematic diagram of the in-situ metrological calibration device for the high dynamic deflection measuring instrument provided by the present invention. Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0019] The following is combined with Figure 1 This invention introduces the in-situ metrological calibration method for the high dynamic deflection measuring instrument, such as... Figure 1 As shown, it includes: Step 101: The road lateral deformation data acquired at each sampling moment during the process from the time the high dynamic deflection measuring device enters the target test area to the time it leaves the target test area is obtained by using the high dynamic deflection measuring device installed in the target test area, and this data is used as the road lateral deformation dataset. Step 102: The dynamic deflection measurement value obtained at each sampling moment during the process of entering and leaving the target measurement area is obtained by the high dynamic deflection measurement device, and used as the original pavement deflection measurement dataset. In this embodiment, a high dynamic deflection measuring device is used to calibrate the high dynamic deflection measuring device.

[0020] The high dynamic deflection measuring device includes a measuring support and multiple line-scanning three-dimensional measuring units mounted on the measuring support.

[0021] A line-scan 3D measurement unit consists of a set of line lasers and a high-frequency 3D camera with their relative positions fixed.

[0022] Preferably, in this embodiment, the sampling frequency of the high-frequency three-dimensional camera in the line scanning three-dimensional measurement unit is not less than 2000Hz / s, the measurement width is not less than one meter, and the elevation measurement range is not less than 10 millimeters; the length of the laser line projected by the line laser is not less than 1 meter.

[0023] The principle of the high dynamic deflection metering device is as follows: a line laser projects a laser line onto the road surface, and then a high-frequency 3D camera captures the laser line to identify the point cloud at the laser line's location, obtaining the image-side elevation information of the laser line's location. Then, through a pre-calibrated coordinate transformation matrix between the image-side coordinates of the high-frequency 3D camera and the object-side coordinates represented by the real-world coordinate system, the elevation information of the laser line can be mapped from the image-side coordinate system to the real-world coordinate system, thereby obtaining the object-side elevation coordinates of the road surface at the laser line. Based on the object-side elevation coordinates of each measurement point on the laser line, the elevation profile of the road surface at the location of the laser line is determined.

[0024] Based on this, before the high-speed moving load passes through the high-dynamic deflection metering device, the control line scanning three-dimensional measurement unit measures to obtain the static elevation profile of the road surface at the location of its laser line; during the process of the high-speed moving load entering and leaving the high-dynamic deflection metering device, the control line scanning three-dimensional measurement unit continuously measures at high frequency to obtain a set of dynamic elevation profiles of the road surface at the location of its laser line.

[0025] It is understandable that by using a high dynamic deflection metering device to obtain the static and dynamic elevation profiles of the cross section corresponding to the laser line at the same location and using the same measurement method, the morphological changes at the corresponding time of each dynamic profile can be accurately obtained by the deviation between the dynamic and static elevation profiles, thus obtaining the pavement deflection measurement data.

[0026] When using a high dynamic deflection metering device to perform in-situ calibration of a high dynamic deflection measuring device, first determine a road section as the target measurement area, and place the measuring bracket on one side of the road in the target measurement area.

[0027] Optionally, the placement and angle of the measuring bracket can be adjusted so that the laser lines emitted by all the line-scanning 3D measuring units on the measuring bracket are projected onto the road surface of the target measuring area along the road width direction, and the laser lines projected by any two line-scanning 3D measuring units do not intersect.

[0028] Preferably, the laser lines projected by any two line-scanning 3D measurement units are parallel to each other.

[0029] Preferably, the position of the point where the measuring bracket directly contacts the road surface is outside the load influence range when the high dynamic measuring device passes the high dynamic deflection metering device.

[0030] Optionally, the extent of the load-affected zone is determined empirically, taking into account the road structure, road condition, and load magnitude of the high-dynamic deflection measuring device.

[0031] With the above setup, the laser lines projected by multiple line scanning 3D measurement units arranged at intervals along the road extension direction on the measuring bracket form a laser line measurement area, which roughly covers the target measurement area.

[0032] Then, the high dynamic deflection metering device is activated, and its preset line scanning three-dimensional measurement unit is controlled to work synchronously. The point cloud of the laser line position corresponding to the high frequency three-dimensional camera is continuously acquired according to the preset sampling frequency. The image-space elevation information of each measuring point position constituting the laser line is obtained, and the object-space elevation of the corresponding position is obtained after coordinate transformation.

[0033] Furthermore, in this embodiment, the high dynamic deflection measurement device is a laser dynamic deflection measurement system (LDD). While providing the load required for road inspection, the high dynamic deflection measurement device obtains the dynamic deflection measurement value of the road surface through the dynamic deflection measurement unit.

[0034] The measuring vehicle of the high dynamic deflection measuring device travels through the target measuring area. During its entry into and exit from the target measuring area, the high dynamic deflection measuring device remains in working condition until the measuring vehicle leaves the target measuring area.

[0035] In the above process, before the measuring vehicle enters the target measurement area, the high dynamic deflection metering device continuously samples to determine the static profile of the target measurement area before loading; during the process of the measuring vehicle entering and leaving the target measurement area, the high dynamic deflection metering device continuously samples to obtain the dynamic profile of the target measurement area under loading at each sampling time, determine the difference between the dynamic profile and the static profile at each sampling time, obtain the road lateral deformation data at each sampling time, and organize the road lateral deformation data at all sampling times in chronological order to obtain the road lateral deformation dataset.

[0036] The road lateral deformation dataset includes a subset of road lateral deformation data obtained by all line-scan 3D measurement units. Each subset of road lateral deformation data includes the road deformation measurement data at each sampling moment during the process of the high-dynamic deflection measurement device entering and leaving the target measurement area at its corresponding cross-sectional position.

[0037] During this process, the high dynamic deflection measurement device also continuously samples the measurement unit mounted on the measurement vehicle to obtain the dynamic deflection measurement value at each sampling moment, and organizes the dynamic deflection measurement values ​​of all sampling moments in chronological order to obtain the original pavement deflection measurement dataset.

[0038] Step 103: Extract the pavement lateral deformation data and the original pavement deflection measurement data at key moments from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively. The key moment represents the moment when the load center of the high dynamic deflection measurement device moves to be aligned with the preset measurement unit in the high dynamic deflection metering device along the driving direction. The preset measurement unit in the high dynamic deflection metering device is a preset line-scan three-dimensional measurement unit in the high dynamic deflection metering device.

[0039] Optionally, if the high dynamic deflection measuring device to be calibrated does not have a rear wheel measuring point, the first line-scan three-dimensional measuring unit passed by the high dynamic deflection measuring device is taken as the preset measuring unit. In this case, each front wheel measuring point of the high dynamic deflection measuring device can find the road lateral deformation data of the corresponding line-scan three-dimensional measuring unit.

[0040] Optionally, if the high dynamic deflection measurement device to be calibrated has n rear wheel measuring points, the (n+1)th line-scan three-dimensional measurement unit is used as the preset measurement unit, so that both the front wheel measuring point and the rear wheel measuring point have corresponding road surface lateral deformation data.

[0041] When the high dynamic deflection measuring device travels to the point where the load center of its load wheel coincides with the measuring line (laser line) of the preset line scanning three-dimensional measuring unit along the direction of travel, the cross-sectional position corresponding to the measuring line deforms into the load center deformation. This moment is the critical moment of the preset line scanning three-dimensional measuring unit.

[0042] The pavement lateral deformation data and the original pavement deflection measurement data at key moments were extracted from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively, so as to perform metrological calibration on the original pavement deflection measurement data using the pavement lateral deformation data.

[0043] Step 104: Based on the pavement lateral deformation data at key moments, the original pavement deflection measurement data at key moments are calibrated to obtain calibrated pavement deflection measurement data.

[0044] The original road surface deflection measurement data consists of the elevation data of a set of measuring points along the road extension direction of the target measurement area, which characterizes the vertical deformation along the road surface.

[0045] The lateral deformation data of the road surface at critical moments consists of multiple sets of lateral deformation data along the road width direction from each measuring unit in the high dynamic deflection metering device at critical moments.

[0046] Therefore, it is necessary to first determine the horizontal distance along the road width between the measuring line of the high dynamic deflection measuring equipment and the high dynamic deflection metering device at critical moments. Based on this horizontal distance, the measuring point corresponding to the measuring line position of the high dynamic deflection measuring equipment can be found in each set of lateral deformation data. The pavement deflection measurement data of each measuring point can be extracted to obtain a set of pavement deflection measurement data along the pavement length direction corresponding to the original pavement deflection measurement data, which can be used for the measurement calibration of the pavement deflection measurement data.

[0047] Understandably, since the measurement unit of the high dynamic deflection measurement equipment is installed on the measurement vehicle, its measurement data must be generated during the loading process of the measured pavement. It cannot determine the original contour of the target measurement area before loading, and it uses a measurement method based on pavement deformation rate, resulting in indirect measurement results. To achieve uniformity in the measurement results of high dynamic deflection, a direct measurement method is needed to obtain direct measurement results of pavement deformation. The high dynamic deflection measurement equipment, however, directly obtains the pavement deformation of the target measurement area under load by calculating the difference between the dynamic and static contours of the pavement. The measurement results are intuitive, and the direct measurement results can be used as deflection measurement data.

[0048] Optionally, a calibration model can be pre-constructed using numerical analysis methods. The deflection measurement data and the original pavement deflection measurement data at key moments can be substituted into the calibration model to obtain calibration parameters and calibrated pavement deflection measurement data, thereby achieving in-situ measurement calibration of the high-precision dynamic deflection measurement device.

[0049] This invention acquires deflection measurement data and original pavement deflection measurement data of the same target test area at the same critical moment through a high dynamic deflection metering device and a high dynamic deflection measurement device. The original pavement deflection measurement data is calibrated by directly measuring the deflection measurement data, resulting in more accurate calibrated pavement deflection measurement data and improving the reliability of the detection results of the high dynamic deflection measurement device.

[0050] The in-situ metrological calibration method for the high dynamic deflection measuring instrument of the present invention further includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Since the critical moment is the moment when the load center of the high dynamic deflection measuring device passes through the measuring line of the preset measuring unit, this embodiment determines the critical moment through the measurement data of the preset measuring unit.

[0051] Specifically, firstly, a set of time-series data of road lateral deformation corresponding to the preset measurement unit is extracted from the road lateral deformation dataset. This is a subset of the lateral deformation data of the preset measurement unit, which represents the measurement data of different measuring points at different times in the measuring line corresponding to the preset measurement unit during the entire process of the high dynamic deflection measuring device passing through the target measuring area.

[0052] In the set of road lateral deformation time series data, the time corresponding to the road lateral deformation data with significant deformation abrupt change is marked as key time period data, thereby determining the key time period when the load wheel corresponding to the load center enters and leaves the preset measurement unit; When the measuring vehicle of the high dynamic deflection measuring device does not pass the measuring line of the preset measuring unit, the laser lines of the preset measuring unit are all projected onto the road surface of the target measuring area. Although the road surface has deflected when the measuring vehicle approaches this measuring line, its deflection data has a small deviation compared to the static profile and is not enough to form a sudden change.

[0053] However, when the load wheel of the measuring vehicle passes over this laser line, part of the laser line is blocked by the load wheel and is directly projected onto the load wheel, causing the measurement data to change abruptly compared to the static contour of the road surface.

[0054] By determining the start time of the mutation and the end time of the mutation, the key time periods when the load wheel corresponding to the load center enters and leaves the preset measurement unit can be determined.

[0055] The midpoint of the critical time period is taken as the critical moment.

[0056] Since the speed of the load wheel of the high dynamic deflection measuring device passing through the preset measuring unit can be approximately uniform, in this embodiment, the midpoint of the critical time period is directly taken as the critical moment, that is, the moment when the load center of the high dynamic deflection measuring device passes through the laser line projected by the preset measuring unit.

[0057] In the in-situ calibration method for the high dynamic deflection measuring instrument of the present invention, the high dynamic deflection measuring device is equipped with a high-frequency signal generator, and both the high dynamic deflection measuring device and the high dynamic deflection measuring device are equipped with a receiving device matched to the high-frequency signal generator. The step of extracting the original pavement deflection measurement data at key moments from the original pavement deflection measurement dataset specifically includes: Determine a first mapping relationship between the road lateral deformation data acquisition time of the high dynamic deflection metering device and the signal reception time of the receiving device installed on it; Since both the high dynamic deflection measurement device and the high dynamic deflection metering device are equipped with high sampling frequencies, in order to achieve accurate time synchronization and determine the time frame corresponding to the key moment in the original pavement deflection measurement data, in this embodiment, a high-frequency signal generator is installed on the high dynamic deflection measurement device, and a receiving device matching the high-frequency signal generator is installed on both the high dynamic deflection measurement device and the high dynamic deflection metering device to receive the signal emitted by the high-frequency signal generator and achieve time synchronization based on the signal.

[0058] Optionally, the high-frequency signal generator can be a GPS clock module or a high-precision temperature-controlled crystal oscillator combined with a wireless transmission module.

[0059] Optionally, the receiving device can be a GPS receiving module or a wireless receiving module corresponding to the wireless transmitting module.

[0060] Taking the GPS clock and receiver module as an example, both GPS receiver modules will receive the PTP signal and time message from the master clock during the process of the high dynamic deflection measuring device passing through the target measurement area.

[0061] Based on this, for a high dynamic deflection metering device, each data point in the road lateral deformation dataset it collects corresponds to a UTC time recorded by its receiving device. This correspondence is the first mapping relationship.

[0062] Based on the first mapping relationship, the corresponding UTC time at the critical moment can be determined.

[0063] Determine a second mapping relationship between the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device and the signal reception time of the receiving device installed on it; Based on the first and second mapping relationships, the associated time corresponding to the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device is determined. The data of the associated time are extracted from the original pavement deflection measurement dataset as the original pavement deflection measurement data corresponding to the key time.

[0064] Similarly, the second mapping relationship characterizes the mapping relationship between the original pavement deflection measurement data acquisition time and the UTC time. Based on the determined UTC time, the associated time corresponding to the original pavement deflection measurement data acquisition time can be determined, which is the critical moment.

[0065] At this point, by extracting the data from the relevant time points in the original pavement deflection measurement dataset, the original pavement deflection measurement data corresponding to the key time points can be obtained.

[0066] The above method achieves a key moment determination method based on time synchronization. In another feasible implementation, the key moment can also be determined based on distance relationships within the original pavement deflection measurement data acquisition time.

[0067] For example, a line laser is installed on a high-dynamic deflection measuring device, projecting a laser line towards the side where the high-precision deflection metering device is located. Before the high-dynamic deflection measuring device passes the high-dynamic deflection metering device, the laser line is projected onto the road surface, and the corresponding elevation data is relatively stable. As the high-dynamic deflection measuring device passes the high-dynamic deflection metering device, part of the laser line is projected onto the measuring support, causing a sudden change in the measured elevation data. The moment this change occurs is the moment when the line laser passes the measuring support.

[0068] Since the installation position of the line laser is fixed, its relative position with the load center of the high dynamic deflection measuring device is also fixed and can be pre-calibrated; similarly, the position between the edge of the measuring bracket and the preset measuring unit is also relatively fixed and can be pre-calibrated. At the moment of abrupt change, the vertical (road extension direction) distance between the load center of the high dynamic deflection measuring device and the preset measuring unit can also be determined.

[0069] Based on this, the sampling time corresponding to the key moment in the original road surface deflection measurement dataset can be determined by the positioning device (encoder) of the high dynamic deflection measurement device itself.

[0070] The in-situ calibration method for the high dynamic deflection measuring instrument of the present invention includes the following steps for calibrating the original pavement deflection measurement data at the key moment based on the pavement lateral deformation data at the key moment: Extract the deformation data at a preset longitudinal position from the road surface transverse deformation data to obtain the road surface longitudinal deformation measurement data; The preset longitudinal position represents the lateral (road width direction) distance between the measuring line of the high dynamic deflection measuring device and the high dynamic metering device.

[0071] Since the distance between each measuring line of the high dynamic deflection measuring device and the high dynamic deflection measuring device is relatively fixed and can be pre-calibrated, and the preset longitudinal position is clearly defined, the measuring point corresponding to the measuring line of the high dynamic deflection measuring device in the transverse deformation data of each road surface can be determined, and the deformation data of the measuring point can be extracted.

[0072] By integrating all the extracted deformation data, the longitudinal deformation measurement data of the road surface can be obtained.

[0073] The original pavement deflection measurement data are calibrated based on the pavement longitudinal deformation measurement data. The preset longitudinal position is determined based on the distance between the high dynamic deflection measuring device and the high dynamic deflection metering device along the road width at the critical moment.

[0074] Based on this, the original pavement deflection measurement data can be calibrated in situ using the directly measured longitudinal deformation data of the pavement, thereby improving the accuracy of the detection results of the high dynamic pavement deflection detection equipment.

[0075] The in-situ metrological calibration method for the high dynamic deflection measuring instrument of the present invention further includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Determine the location of data abrupt changes in the time series data of the road surface lateral deformation; Determine the first distance between the location where the data mutation occurs and the measurement unit corresponding to the road surface lateral deformation time series data; The preset longitudinal position is determined based on the first distance.

[0076] In this embodiment, a preset longitudinal position is determined based on a set of road surface lateral deformation time series data corresponding to a preset measurement unit.

[0077] Specifically, the preset measurement unit projects a laser line onto the ground. Before the high dynamic deflection measurement device arrives, the elevation data of each measuring point on the laser line represents the elevation data of the corresponding section. Their elevation values ​​are relatively similar, and even if affected by the load of the high dynamic deflection measurement device, there will be no significant sudden change until the tire of the high dynamic deflection measurement device passes the measuring line position, so that part of the laser line projected on the ground is projected onto the tire.

[0078] At this point, the elevation data corresponding to the measuring points still projected onto the road surface will not change significantly, but the elevation values ​​corresponding to the measuring points projected onto the tires will experience a large abrupt change.

[0079] Based on the position of the measurement point that causes the abrupt change in the laser line, the first distance between it and the corresponding measurement unit can be determined.

[0080] By determining the preset longitudinal position based on the first distance, the measuring point corresponding to the measuring line of the high dynamic deflection measuring device can be found at the measuring point of each measuring unit.

[0081] The in-situ metrological calibration method for the high dynamic deflection measuring instrument of the present invention further includes: Acquire longitudinal deformation measurement data of the road surface under various preset road structures and different preset measurement speeds, and obtain the original road surface deflection measurement data that matches them; Using numerical analysis, calibration models for each preset road structure were established for all measuring points of the high dynamic deflection measuring device.

[0082] In this embodiment, calibration models are established for all measuring points in the high dynamic deflection measuring device under each preset road structure to improve calibration accuracy.

[0083] Therefore, a variety of typical road structures are predetermined, and longitudinal deformation measurement data of the road surface and original road surface deflection measurement data are measured at various preset measurement speeds. For each measuring point, a calibration model is constructed for each preset road structure.

[0084] Optionally, different preset measurement speeds can be 30 km / h, 50 km / h, 70 km / h and 90 km / h.

[0085] In other feasible implementations, the longitudinal deformation measurement data of the road surface can be used as a label, and the original road surface deflection measurement data that matches it can be used as a sample to construct a dataset and train a neural network model as a calibration model.

[0086] In the in-situ metrological calibration method of the high dynamic deflection measuring instrument of the present invention, the installation position of each measuring unit in the high dynamic deflection measuring device is determined according to the relative installation position of the deflection basin measuring point of the corresponding measuring unit in the high dynamic deflection measuring device, so that at critical moments, each measuring point in the high dynamic deflection measuring device has one and only one measuring line projected by the measuring unit of the corresponding high dynamic deflection measuring device.

[0087] In one feasible implementation, the number and position of measuring units in the high dynamic deflection measuring device are determined based on the number and relative position of the deflection basin measuring points in the high dynamic deflection measuring device, so as to ensure that at critical moments, each measuring point in the high dynamic deflection measuring device has one and only one measuring line projected by the corresponding measuring unit of the high dynamic deflection measuring device.

[0088] In another feasible implementation, the installation position of each measuring point of the high dynamic deflection measuring device can have a certain error allowable range, so that at critical moments, within the preset distance range of each measuring point in the high dynamic deflection measuring device, there is one and only one laser line projected by the measuring unit of the high dynamic deflection measuring device.

[0089] Optionally, the preset distance range is 5 mm.

[0090] In the in-situ calibration method of the high dynamic deflection measuring instrument of the present invention, a safety distance sensor is installed on the side of the high dynamic deflection measuring device facing the direction of travel of the high dynamic deflection measuring device, for detecting the real-time distance between the sensor and the high dynamic deflection measuring device along the road width direction. If the real-time distance is less than a preset safety threshold, a safety warning is issued for the high dynamic deflection measuring device.

[0091] Optionally, the safe distance sensor can be one or more of LiDAR, millimeter-wave radar, binocular vision camera, or line-scan 3D sensor.

[0092] The safety distance sensor is used to detect the real-time lateral (road width) distance between the high dynamic deflection measuring device and the high dynamic deflection metering device as the latter approaches the former. A small lateral distance indicates that the travel path of the high dynamic deflection measuring device may interfere with the latter.

[0093] Optionally, a preset safety threshold can be determined based on the installation location of the safety distance sensor, and a safety warning can be issued for the high dynamic deflection measurement device when the real-time distance is less than the preset safety threshold.

[0094] In the in-situ calibration method of the high dynamic deflection measuring instrument of the present invention, at the critical moment, the support point of the measuring unit used to set up the high dynamic deflection measuring device is located outside the road surface deformation area.

[0095] As a preferred embodiment, at the critical moment, the support point of the high dynamic deflection metering device that is in direct contact with the road surface needs to be located outside the road surface deformation zone to prevent road surface deformation from affecting the metering data of the high dynamic deflection metering device.

[0096] The road surface deformation zone refers to the area in the target measurement zone where deformation occurs as the high dynamic deflection measurement equipment passes through the target measurement zone.

[0097] The in-situ calibration device for the high dynamic deflection measuring instrument provided by the present invention is described below. The in-situ calibration device for the high dynamic deflection measuring instrument described below can be referred to in correspondence with the in-situ calibration method for the high dynamic deflection measuring instrument described above.

[0098] like Figure 2 As shown, the in-situ metrological calibration device for the high dynamic deflection measuring instrument includes a metrological data acquisition module 201, a raw data acquisition module 202, a key data matching module 203, and a calibration data determination module 204. The measurement data acquisition module 201 is used to acquire road lateral deformation data at each sampling moment during the process from the time the high dynamic deflection measuring device enters the target measurement area to the time it leaves the target measurement area, and use it as a road lateral deformation dataset. The raw data acquisition module 202 is used to acquire the dynamic deflection measurement values ​​at each sampling moment during the process of the high dynamic deflection measurement device entering and leaving the target measurement area, as the raw pavement deflection measurement dataset. In this embodiment, a high dynamic deflection measuring device is used to calibrate the high dynamic deflection measuring device.

[0099] The high dynamic deflection measuring device includes a measuring support and multiple line-scanning three-dimensional measuring units mounted on the measuring support.

[0100] A line-scan 3D measurement unit consists of a set of line lasers and a high-frequency 3D camera with their relative positions fixed.

[0101] Preferably, in this embodiment, the sampling frequency of the high-frequency three-dimensional camera in the line scanning three-dimensional measurement unit is not less than 2000Hz / s, the measurement width is not less than one meter, the elevation measurement range is not less than 10 mm, and the elevation measurement accuracy is less than 0.01 mm; the length of the laser line projected by the line laser is not less than 1 meter.

[0102] The principle of the high dynamic deflection metering device is as follows: a line laser projects a laser line onto the road surface, and then a high-frequency 3D camera captures the laser line to identify the point cloud at the laser line's location, obtaining the image-side elevation information of the laser line's location. Then, through a pre-calibrated coordinate transformation matrix between the image-side coordinates of the high-frequency 3D camera and the object-side coordinates represented by the real-world coordinate system, the elevation information of the laser line can be mapped from the image-side coordinate system to the real-world coordinate system, thereby obtaining the object-side elevation coordinates of the road surface at the laser line. Based on the object-side elevation coordinates of each measurement point on the laser line, the elevation profile of the road surface at the location of the laser line is determined.

[0103] Based on this, before the high-speed moving load passes through the high-dynamic deflection metering device, the control line scanning three-dimensional measurement unit measures to obtain the static elevation profile of the road surface at the location of its laser line; during the process of the high-speed moving load entering and leaving the high-dynamic deflection metering device, the control line scanning three-dimensional measurement unit continuously measures at high frequency to obtain a set of dynamic elevation profiles of the road surface at the location of its laser line.

[0104] It is understandable that by using a high dynamic deflection metering device to obtain the static and dynamic elevation profiles of the cross section corresponding to the laser line at the same location and using the same measurement method, the morphological changes at the corresponding time of each dynamic profile can be accurately obtained by the deviation between the dynamic and static elevation profiles, thus obtaining the pavement deflection measurement data.

[0105] When using a high dynamic deflection metering device to perform in-situ calibration of a high dynamic deflection measuring device, first determine a road section as the target measurement area, and place the measuring bracket on one side of the road in the target measurement area.

[0106] Optionally, the placement and angle of the measuring bracket can be adjusted so that the laser lines emitted by all the line-scanning 3D measuring units on the measuring bracket are projected onto the road surface of the target measuring area along the road width direction, and the laser lines projected by any two line-scanning 3D measuring units do not intersect.

[0107] Preferably, the laser lines projected by any two line-scanning 3D measurement units are parallel to each other.

[0108] Preferably, the position of the point where the measuring bracket directly contacts the road surface is outside the load influence range when the high dynamic measuring device passes the high dynamic deflection metering device.

[0109] Optionally, the extent of the load-affected zone is determined empirically, taking into account the road structure, road condition, and load magnitude of the high-dynamic deflection measuring device.

[0110] With the above setup, the laser lines projected by multiple line scanning 3D measurement units arranged at intervals along the road extension direction on the measuring bracket form a laser line measurement area, which roughly covers the target measurement area.

[0111] Then, the high dynamic deflection metering device is activated, and its preset line scanning three-dimensional measurement unit is controlled to work synchronously. The point cloud of the laser line position corresponding to the high frequency three-dimensional camera is continuously acquired according to the preset sampling frequency. The image-space elevation information of each measuring point position constituting the laser line is obtained, and the object-space elevation of the corresponding position is obtained after coordinate transformation.

[0112] Furthermore, in this embodiment, the high dynamic deflection measurement device is a laser dynamic deflection measurement system (LDD). The high dynamic deflection measurement device provides the load required for road inspection while acquiring the dynamic deflection measurement value of the road surface through dynamic detection.

[0113] The measuring vehicle of the high dynamic deflection measuring device travels through the target measuring area. During its entry into and exit from the target measuring area, the high dynamic deflection measuring device remains in working condition until the measuring vehicle leaves the target measuring area.

[0114] In the above process, before the measuring vehicle enters the target measurement area, the high dynamic deflection metering device continuously samples to determine the static profile of the target measurement area before loading; during the process of the measuring vehicle entering and leaving the target measurement area, the high dynamic deflection metering device continuously samples to obtain the dynamic profile of the target measurement area under loading at each sampling time, determine the difference between the dynamic profile and the static profile at each sampling time, obtain the road lateral deformation data at each sampling time, and organize the road lateral deformation data at all sampling times in chronological order to obtain the road lateral deformation dataset.

[0115] The road lateral deformation dataset includes a subset of road lateral deformation data obtained by all line-scan 3D measurement units. Each subset of road lateral deformation data includes the road deformation measurement data at each sampling moment during the process of the high-dynamic deflection measurement device entering and leaving the target measurement area at its corresponding cross-sectional position.

[0116] During this process, the high dynamic deflection measurement device also continuously samples the measurement unit mounted on the measurement vehicle to obtain the dynamic deflection measurement value at each sampling moment, and organizes the dynamic deflection measurement values ​​of all sampling moments in chronological order to obtain the original pavement deflection measurement dataset.

[0117] The key data matching module 203 is used to extract the road lateral deformation data and the original road deflection measurement data at key moments from the road lateral deformation dataset and the original road deflection measurement dataset, respectively. The key moment represents the moment when the load center of the high dynamic deflection measurement device moves to be aligned with the preset measurement unit in the high dynamic deflection metering device along the driving direction. The preset measurement unit in the high dynamic deflection metering device is a preset line-scan three-dimensional measurement unit in the high dynamic deflection metering device.

[0118] Optionally, if the high dynamic deflection measuring device to be calibrated does not have a rear wheel measuring point, the first line-scan three-dimensional measuring unit passed by the high dynamic deflection measuring device is taken as the preset measuring unit. In this case, each front wheel measuring point of the high dynamic deflection measuring device can find the road lateral deformation data of the corresponding line-scan three-dimensional measuring point unit.

[0119] Optionally, if the high dynamic deflection measurement device to be calibrated has n rear wheel measuring points, the (n+1)th line-scan three-dimensional measurement unit is used as the preset measurement unit, so that both the front wheel measuring point and the rear wheel measuring point have corresponding road surface lateral deformation data.

[0120] When the high dynamic deflection measuring device travels to the point where the load center of its load wheel coincides with the measuring line (laser line) of the preset line scanning three-dimensional measuring unit along the direction of travel, the deformation of the cross-section position corresponding to the measuring line becomes the deformation of the load center. This moment is the critical moment of the preset line scanning three-dimensional measuring unit.

[0121] The pavement lateral deformation data and the original pavement deflection measurement data at key moments were extracted from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively, so as to perform metrological calibration on the original pavement deflection measurement data using the pavement lateral deformation data.

[0122] The calibration data determination module 204 is used to perform metrological calibration on the original pavement deflection measurement data based on the pavement lateral deformation data to obtain calibrated pavement deflection measurement data.

[0123] The original road surface deflection measurement data consists of the elevation data of a set of measuring points along the road extension direction of the target measurement area, which characterizes the vertical deformation along the road surface.

[0124] The lateral deformation data of the road surface at critical moments consists of multiple sets of lateral deformation data along the road width direction from each measuring unit in the high dynamic deflection metering device at critical moments.

[0125] Therefore, it is necessary to first determine the horizontal distance along the road width between the measuring line of the high dynamic deflection measuring equipment and the high dynamic deflection metering device at critical moments. Based on this horizontal distance, the measuring point corresponding to the measuring line position of the high dynamic deflection measuring equipment can be found in each set of lateral deformation data. The pavement deflection measurement data of each measuring point can be extracted to obtain a set of pavement deflection measurement data along the pavement length direction corresponding to the original pavement deflection measurement data, which can be used for the measurement calibration of the pavement deflection measurement data.

[0126] Understandably, since the measurement unit of the high dynamic deflection measurement equipment is installed on the measurement vehicle, its measurement data must be generated during the loading process of the measured pavement. It's impossible to determine the original profile of the target measurement area before loading. Therefore, it uses a measurement method based on pavement deformation rate, resulting in indirect measurement results. To achieve uniformity in the measurement results of high dynamic deflection, a direct measurement method is needed to obtain direct pavement deformation measurement results. The high dynamic deflection measurement equipment, however, directly obtains the pavement deformation of the target measurement area under load by calculating the difference between the dynamic and static profiles of the pavement. The measurement results are intuitive, and these direct measurement results are used as deflection measurement data.

[0127] Optionally, a calibration model can be pre-constructed using numerical analysis methods. The deflection measurement data and the original pavement deflection measurement data at key moments can be substituted into the calibration model to obtain calibration parameters and calibrated pavement deflection measurement data, thereby achieving in-situ measurement calibration of the high-precision dynamic deflection measurement device.

[0128] This invention acquires deflection measurement data and original pavement deflection measurement data of the same target test area at the same critical moment through a high dynamic deflection metering device and a high dynamic deflection measurement device. The original pavement deflection measurement data is calibrated by directly measuring the deflection measurement data, resulting in more accurate calibrated pavement deflection measurement data and improving the reliability of the detection results of the high dynamic deflection measurement device.

[0129] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for in-situ metrological calibration of a high dynamic deflection measuring instrument, characterized in that, include: The road lateral deformation data at each sampling moment during the process from before the high dynamic deflection measuring device enters the target test area to when it leaves the target test area are obtained by the high dynamic deflection measuring device installed in the target test area, and this data is used as the road lateral deformation dataset. The dynamic deflection measurement value is obtained at each sampling moment during the process of entering and leaving the target measurement area by the high dynamic deflection measurement device, which is used as the original pavement deflection measurement dataset. The key moments are extracted from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively. The key moments represent the moments when the load center of the high dynamic deflection measurement device moves to the point where it is aligned with the preset measurement unit in the high dynamic deflection measurement device along the driving direction. Based on the lateral deformation data of the road surface at key moments, the original road surface deflection measurement data at key moments are calibrated to obtain calibrated road surface deflection measurement data.

2. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to claim 1, characterized in that, Also includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Based on the abrupt change times in the set of road lateral deformation time series data, determine the key time periods when the load wheel corresponding to the load center enters and leaves the preset measurement unit; The midpoint of the critical time period is taken as the critical moment.

3. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to claim 2, characterized in that, The high-dynamic deflection measuring device is equipped with a high-frequency signal generator, and both the high-dynamic deflection measuring device and the high-dynamic deflection metering device are equipped with a receiving device matched to the high-frequency signal generator. The step of extracting key moment original pavement deflection measurement data from the original pavement deflection measurement dataset specifically includes: Determine a first mapping relationship between the road lateral deformation data acquisition time of the high dynamic deflection metering device and the signal reception time of the receiving device installed on it; Determine a second mapping relationship between the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device and the signal reception time of the receiving device installed on it; Based on the first and second mapping relationships, the associated time corresponding to the original pavement deflection measurement data acquisition time of the high dynamic deflection measurement device is determined. The data of the associated time are extracted from the original pavement deflection measurement dataset as the original pavement deflection measurement data corresponding to the key time.

4. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to claim 1, characterized in that, The steps for calibrating the original pavement deflection measurement data at the key moments based on the pavement lateral deformation data at the key moments specifically include: Extract the deformation data at a preset longitudinal position from the road surface transverse deformation data to obtain the road surface longitudinal deformation measurement data; The original pavement deflection measurement data are calibrated based on the pavement longitudinal deformation measurement data. The preset longitudinal position is determined based on the distance between the high dynamic deflection measuring device and the high dynamic deflection metering device along the road width at the critical moment.

5. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to claim 4, characterized in that, Also includes: Extract a set of time-series data of lateral road deformation corresponding to the preset measurement unit from the lateral road deformation dataset; Determine the location of data abrupt changes in the time series data of the road surface lateral deformation; Determine the first distance between the location where the data mutation occurs and the measurement unit corresponding to the road surface lateral deformation time series data; The preset longitudinal position is determined based on the first distance.

6. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to claim 4, characterized in that, Also includes: Acquire longitudinal deformation measurement data of the road surface under various preset road structures and different preset measurement speeds, and obtain the original road surface deflection measurement data that matches them; Using numerical analysis, calibration models for each preset road structure were established for all measuring points of the high dynamic deflection measuring device.

7. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to any one of claims 1-6, characterized in that, The installation position of each measuring unit in the high dynamic deflection measuring device is determined according to the relative installation position of the deflection basin measuring point of the corresponding measuring unit in the high dynamic deflection measuring device, so that at critical moments, each measuring point in the high dynamic deflection measuring device has one and only one measuring line projected by the measuring unit of the corresponding high dynamic deflection measuring device.

8. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to any one of claims 1-6, characterized in that, A safety distance sensor is installed on the side of the high dynamic deflection metering device facing the direction of travel of the high dynamic deflection measuring device, in order to detect the real-time distance between the sensor and the high dynamic deflection metering device along the road width direction. If the real-time distance is less than a preset safety threshold, a safety warning is issued for the high dynamic deflection measuring device.

9. The in-situ metrological calibration method for a high dynamic deflection measuring instrument according to any one of claims 1-6, characterized in that, At the critical moment, the support point of the measuring unit used to set up the high dynamic deflection metering device is located outside the road surface deformation zone, where it is in direct contact with the road surface.

10. An in-situ metrological calibration device for a high dynamic deflection measuring instrument, characterized in that, include: The measurement data acquisition module is used to acquire road lateral deformation data at each sampling moment during the process from the time the high dynamic deflection measuring device enters the target measurement area to the time it leaves the target measurement area, using the high dynamic deflection measuring device installed in the target measurement area, as the road lateral deformation dataset. The raw data acquisition module is used to acquire the dynamic deflection measurement values ​​at each sampling moment during the process of the high dynamic deflection measurement device entering and leaving the target measurement area, as the raw pavement deflection measurement dataset. The key data matching module is used to extract key moment lateral deformation data and original pavement deflection measurement data from the pavement lateral deformation dataset and the original pavement deflection measurement dataset, respectively. The key moment represents the moment when the load center of the high dynamic deflection measuring device moves to be aligned with the preset measuring unit in the high dynamic deflection measuring device along the driving direction. The calibration data determination module is used to perform metrological calibration on the original pavement deflection measurement data based on the pavement lateral deformation data to obtain calibrated pavement deflection measurement data.

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