A method for detecting height difference at interface between sub-rail of four-way vehicle rack and exchange rail

Abstract

The present disclosure relates to a method for detecting height difference at the interface of a sub-track and a switching track of a four-way vehicle rack. The method comprises obtaining first cross-section data, second cross-section data and vehicle body attitude data collected when the four-way vehicle passes through the interface of the sub-track and the switching track. The first cross-section data comprises a plurality of sub-track lower track lateral coordinate values and a plurality of sub-track lower track actual ranging. The second cross-section data comprises a plurality of switching track track lateral coordinate values and a plurality of switching track track actual ranging. Based on the plurality of sub-track lower track actual ranging, the plurality of switching track track actual ranging and the vehicle body attitude data, a plurality of sub-track lower track surface compensation ranging and a plurality of switching track track surface compensation ranging are determined. Based on the plurality of sub-track lower track surface compensation ranging and the plurality of switching track track surface compensation ranging, the height difference at the interface of the sub-track and the switching track is determined. The embodiment of the present disclosure captures the cross-section data of the tracks on both sides of the interface, compensates and calculates the height difference by using a plurality of discrete sampling points, detects accurately, and helps track maintenance.

Description

Technical Field

[0001] This disclosure relates to the field of testing technology for four-way vehicle automated warehousing equipment, and more specifically, to a method for detecting the height difference at the interface between the sub-rails and the exchange rails of a four-way vehicle rack. Background Technology

[0002] With the development of automated warehousing technology, four-way shuttles (hereinafter referred to as "four-way shuttles") are widely used in high-density warehousing systems due to their high space utilization and flexible operation. To ensure the smooth operation of four-way shuttles, the flatness of the track surface is usually checked. If there is a deviation in flatness (such as depressions or protrusions), it will cause the four-way shuttle to shake, jam, or even damage the wheels and cause goods to tilt and fall, affecting the efficiency and safety of warehousing operations. However, the track routes in actual warehousing systems are complex. Four-way shuttles need to use the main rail to shuttle between multiple racks and then use the reversing rail to run to the sub-rail under the designated rack. There are gaps at the interface between the sub-rail and the reversing rail, and the step difference in the gap can also affect the smooth operation of the four-way shuttle. Summary of the Invention

[0003] The embodiments of this disclosure provide a method for detecting the height difference at the interface between the subrail and the exchange rail of a four-way vehicle rack.

[0004] In a first aspect of this disclosure, a method for detecting the height difference at the interface between a four-way vehicle rack subrail and an exchange rail is provided. The method includes acquiring first cross-sectional data, second cross-sectional data, and vehicle posture data collected as the four-way vehicle passes the interface between the subrail and the exchange rail. The first cross-sectional data includes multiple lateral coordinate values ​​of the subrail tracks and multiple actual distance measurements of the subrail surface collected at the lateral coordinates of each subrail track. The second cross-sectional data includes multiple lateral coordinate values ​​of the exchange rail tracks and multiple actual distance measurements of the exchange rail surface collected at the lateral coordinates of each exchange rail track. The lateral coordinate values ​​of the subrail tracks are the same as the lateral coordinate values ​​of the exchange rail tracks. The vehicle posture data includes a first pitch angle and a first roll angle. The method further includes determining multiple subrail track compensation distances and multiple exchange rail track compensation distances based on the actual distance measurements of the subrail tracks, the actual distance measurements of the exchange rail surfaces, and the vehicle posture data. Furthermore, the method also includes determining the height difference at the interface between the subrail and the exchange rail based on the multiple subrail track compensation distances and the multiple exchange rail track compensation distances.

[0005] It should be understood that the description in the Summary of the Invention section is not intended to limit the key or essential features of the embodiments of this disclosure, nor is it intended to restrict the scope of this disclosure. Other features of this disclosure will become readily apparent from the following description. Attached Figure Description

[0006] The above and other objects, features, and advantages of embodiments of the present disclosure will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of the present disclosure are illustrated in the drawings by way of example and not limitation.

[0007] Figure 1 A schematic diagram of an example environment in which some embodiments of the present disclosure may be implemented is shown;

[0008] Figure 2 Some embodiments of this disclosure are shown. Figure 1 An enlarged diagram of part A in the middle;

[0009] Figure 3 A flowchart illustrating a method for detecting the height difference at the interface between a four-way vehicle rack subrail and an exchange rail, according to some embodiments of this disclosure, is shown.

[0010] Figure 4 A schematic diagram illustrating the height difference detection process at the interface between the four-way rack subrail and the exchange rail, according to some embodiments of this disclosure;

[0011] Figure 5 A schematic diagram of the height difference detection process at the interface between the four-way rack subrail and the exchange rail, according to some other embodiments of this disclosure, is shown.

[0012] In the various figures, the same or corresponding reference numerals indicate the same or corresponding parts. Detailed Implementation

[0013] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0014] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0015] As mentioned earlier, four-way trolleys are widely used in high-density storage systems. These trolleys move between multiple racks by running on a main rail. Multiple reversing rails are vertically connected to the main rail, each engaging with a sub-rail at the bottom of the rack on either side of the main rail. When a four-way trolley enters a rack, its wheels switch and travel along the reversing rail to reach the bottom of the rack. The four-way trolley runs between the upper and lower surfaces of the sub-rails. The lower surface of the sub-rail is used for the four-way wheels, while the upper surface supports the bottom of the pallet carried by the trolley. The interface between the sub-rail and the reversing rail is a critical connection point in the rail system. Any height difference at this interface will directly cause impact vibrations when the four-way trolley passes over it. This can range from accelerating wear on the wheels and rails, shortening the equipment's lifespan, to causing safety accidents such as vehicle deviation and derailment, while also affecting the positioning accuracy and operational efficiency of goods handling.

[0016] In some related technologies, sensors installed on the four-way vehicle continuously collect distance measurements between the vehicle and the track surface. The overall flatness of the track surface is then determined based on the difference between the maximum and minimum distance measurements. This technology is used for flatness detection of the track surface for four-way vehicle operation, but it does not consider the impact and vibration effects experienced by the vehicle in complex dynamic scenarios such as track changes. Furthermore, this flatness calculation method provides a coarse calculation of the entire track, resulting in low accuracy and making it difficult to accurately maintain the track.

[0017] To address this, according to embodiments of this disclosure, a method for detecting the height difference at the interface between a four-way vehicle rack subrail and an exchange rail is provided. This method involves collecting the dynamic vehicle posture of the four-way vehicle as it passes the interface between the subrail and the exchange rail, as well as the track surface distance measurements of the two rails at the interface. The vehicle posture is then used to compensate and correct the track surface distance measurements. Finally, the height difference at the interface is calculated based on the compensated track surface distance measurements. The track surface distance measurements for each rail are collected from multiple transverse coordinates of the rail.

[0018] In this way, data is collected online and dynamically detected as the four-way vehicle passes the interface. By combining the stress and vibration conditions at the moment of track switching and through multi-source data fusion (including ranging and attitude), the elevation difference at the track interface can be detected more accurately. Specifically, using attitude data to compensate for the original ranging eliminates the coupling effect of the vehicle's own attitude changes on the measurement results. The two track cross-section data at the interface each contain multiple sampling points, constructing a microscopic contour model of the sub-rail and exchange rail interface. This accurately depicts the distribution of the elevation difference, facilitating accurate detection of the elevation difference at the track interface and providing more accurate guidance for subsequent track grinding or adjustment.

[0019] Figure 1 A schematic diagram of an example environment that may be implemented according to some embodiments of the present disclosure is shown. Figure 2 Some embodiments of this disclosure are shown. Figure 1 An enlarged diagram of part A in the middle. (See diagram below.) Figure 1 As shown, the four-way vehicle 200 runs on the sub-rail 303 and travels on the lower rail surface 303-1 of the sub-rail. A four-way vehicle rack track detection device 100 is installed on the four-way vehicle 200. The main rail 301 is vertically mounted on the reversing rail 302, and both ends of the reversing rail 302 are respectively engaged with the sub-rail 303. The detection device 100 includes a housing, outside which are two first laser detectors 106-1 (only one is shown in the figure due to perspective), respectively mounted on both sides of the housing along its length via brackets; and two second laser detectors 104-1 and 104-2, respectively mounted on both ends of the front side of the housing via brackets. The first laser detectors are used to detect the distance between themselves and the upper rail surface of the sub-rail, and the second laser detectors are used to detect the distance between themselves and the lower rail surface of the sub-rail, or the distance between themselves and the main rail surface. In some examples, the laser detectors may be line laser sensors with a measurement accuracy ≤ ±0.1 mm and a measurement range of 50-500 mm. In addition, the housing 102 houses a data processing module and a tilt sensor (not shown in the figure). The data processing module is electrically connected to the first and second laser detectors and the tilt sensor, respectively. It can receive data collected by the detectors and sensors, perform calculations using the detection methods described below, and also perform over-limit judgments and mark the locations of depressions / protrusions to assist in track maintenance. In some examples, the data processing module can use an ARM-based embedded processor, which can process multi-sensor data in real time, reducing detection latency.

[0020] The housing is detachably mounted on the roof of the four-way vehicle. In some embodiments, the bottom of the housing has a magnetic structure that allows it to be magnetically attached to the roof of the four-way vehicle. This embodiment allows the housing to be installed on different sides of the four-way vehicle as needed for detection, without altering the vehicle's structure. For example, as shown in the figure, the side with the second laser detectors 104-1 and 104-2 is installed facing outwards, with the second laser detectors 104-1 and 104-2 located above the lower rail surface 303-1 of the subrail. As seen in the figure, the subrail consists of two tracks, and the wheels on both sides of the four-way vehicle travel on the two tracks of the subrail (and on the lower rail surface). Correspondingly, the two second laser detectors distributed on both sides of the four-way vehicle detect the flatness of the corresponding travel tracks. This embodiment also utilizes the second laser detectors to detect the rail surface distance on both sides of the subrail and the exchange rail interface 400 (e.g., data acquisition). Figure 2 (Measuring the distance between the sub-rail surface 400-1 and the exchange rail surface 400-2 at the interface), thereby detecting the height difference at interface 400.

[0021] like Figure 1As shown, an inertial measurement module 108 is located on the front side of the housing. The inertial measurement module 108 includes a three-axis accelerometer and a three-axis gyroscope. This module is used to collect vehicle body vibration, three-axis acceleration, and angular velocity data and send them to the data processing module. The data processing module fuses the attitude data collected by the inertial measurement module 108 to eliminate detection errors caused by vehicle body tilt and vibration, thereby improving detection accuracy. The housing also contains an independent power supply module, which can use a rechargeable lithium battery to power the entire detection device. This module is equipped with a charging interface, supports fast charging, and has a low battery reminder function to prevent power outages during detection. The housing also contains a wireless transmission module, using WiFi or Bluetooth, electrically connected to the data processing module. This module is used to upload processed detection data and over-limit marking information to the warehouse management system, enabling real-time data synchronization and remote viewing. It can also upload detection data to the warehouse management system, which can then use the detection methods described below to calculate the height difference at the track interface, the flatness of the track surface, and can also perform over-limit judgments and mark the locations of depressions / protrusions to assist in track maintenance.

[0022] Figure 3 A flowchart of a method 300 for detecting the height difference at the interface between a four-way vehicle rack subrail and an exchange rail, according to some embodiments of this disclosure, is shown. Figure 3 As shown in block 302, method 300 can acquire first cross-sectional data, second cross-sectional data, and vehicle attitude data collected by the four-way vehicle when passing the interface between the subrail and the exchange rail. The first cross-sectional data includes multiple lateral coordinate values ​​of the subrail tracks and multiple actual distance measurements of the subrail track surfaces collected at the lateral coordinates of each subrail track. The second cross-sectional data includes multiple lateral coordinate values ​​of the exchange rail tracks and multiple actual distance measurements of the exchange rail surfaces collected at the lateral coordinates of each exchange rail track. The multiple lateral coordinate values ​​of the subrail tracks are the same as the multiple lateral coordinate values ​​of the exchange rail tracks. The vehicle attitude data includes a first pitch angle and a first roll angle. In some embodiments, the four-way vehicle travels unloaded on the subrail and the exchange rail at a speed v, and a second laser detector collects the first and second cross-sectional data. Figure 2 Taking the coordinate system as an example, the four-way vehicle travels from the sub-rail to the switching rail, collecting the travel coordinate value y1 for the first cross-section data and the travel coordinate value y2 for the second cross-section data. The first cross-section data includes multiple sets of lateral coordinate values ​​x from the sub-rail's lower track. 子 Actual distance measurement z on the lower rail surface of the sub-rail 子 The data constitutes the second section data, which includes multiple sets of x-coordinate values ​​from the exchange track. 交 Actual distance measurement Z on the rail surface of the exchange track 交 The data consists of the following: the lateral coordinate values ​​of the sub-rail and the exchange rail take values ​​within their respective rail widths, and multiple sets of lateral coordinate values ​​all take the same value, i.e., x. 子 =x 交For example, in the diagram, the width of the lower rail surface of one sub-rail is d1, the width of the rail surface of one exchange rail is d2, and the lateral coordinate value of the lower rail of the sub-rail is x. 子 ∈[0,d1], Exchange track horizontal coordinate value x 交 ∈[0,d2], usually d1 and d2 are equal. When n horizontal coordinate values ​​are taken, n distance measurements can be obtained. Therefore, the first and second cross-sectional data each have n distance measurements, namely {y1, (x... 子1 , z 子1 ), ..., (x 子n , z 子n )}、{y2,(x 交1 , z 交1 ), ..., (x 交n , z 交n In addition, the vehicle body attitude data is collected at the interface between the subrail and the exchange rail in all four directions, including the first pitch angle and the first roll angle. .

[0023] In some implementations, triaxial acceleration and triaxial angular velocity are also acquired from the inertial measurement module. The raw acceleration and angular velocity data contain high-frequency noise generated by driving bumps. The processing module uses a Kalman filter algorithm to smooth the data, filtering out instantaneous vibration interference. The filtered data is used as auxiliary verification data. If the vibration exceeds the vibration threshold, the acquired data is considered abnormal and needs to be re-detected. If the vibration does not exceed the vibration threshold, it is determined that the vehicle is currently driving stably in all four directions without severe bumps, and the detection data is usable.

[0024] In block 304, method 300 can determine compensated distances for multiple sub-rail under-rail surfaces and multiple exchange rail surfaces based on actual distance measurements of multiple sub-rail under-rail surfaces, actual distance measurements of multiple exchange rail surfaces, and vehicle attitude data. In some implementations, vehicle pitch and roll can cause distortion of the original height measured by laser; a compensation formula is used to correct all distance measurements point by point.

[0025] Corrected height: .in, This refers to the actual distance measured by the second laser detector on the subrail surface or the actual distance measured on the exchanged rail surface under the current attitude of the vehicle body. To correct for vehicle tilt error, the subrail surface is used for distance measurement or the exchanged rail surface is used for compensation distance measurement.

[0026] In block 306, method 300 can determine the elevation difference at the interface between the subrail and the exchange rail based on multiple subrail under-rail surface compensation distance measurements and multiple exchange rail under-rail surface compensation distance measurements. In some implementations, the distance measurement deviation at multiple identical lateral coordinate values ​​is determined based on multiple subrail under-rail surface compensation distance measurements and multiple exchange rail under-rail surface compensation distance measurements. In one example, the distance measurement deviation at each lateral coordinate value is the absolute value of the difference between the subrail under-rail surface compensation distance measurement and the exchange rail under-rail surface compensation distance measurement, i.e. , The distance measurement deviation is at the i-th horizontal coordinate. and These are the subrail surface compensation distance measurement and the exchange rail surface compensation distance measurement under the i-th lateral coordinate, respectively. The maximum distance measurement deviation is determined from multiple distance measurement deviations and is defined as the elevation difference at the interface between the subrail and the exchange rail.

[0027] In this way, data acquisition and processing are completed during operation, eliminating the need for specialized detection equipment to stop and scan, and the need for manual point-by-point measurement. Furthermore, by capturing the impact of vibrations on the gaps at the interface between the subrail and the exchange rail during dynamic movement, it can accurately detect elevation differences and perform targeted maintenance on the track interfaces, ensuring smooth operation of the four-way vehicle at the track interfaces. During the detection process, on the one hand, by introducing vehicle attitude data (pitch angle, roll angle), mathematical compensation is applied to the original distance measurement, effectively eliminating geometric measurement errors caused by changes in the vehicle's own attitude. On the other hand, multi-point acquisition of cross-sectional data avoids missing local changes due to insufficient sampling points, and by calculating the deviation of all sampling points and taking the maximum value, the most severe protrusions or indentations at the interface can be captured, providing a more reliable basis for track safety assessment.

[0028] Furthermore, the method 300 can also respond to situations where the height difference at the interface between the subrail and the switching rail exceeds the joint threshold, determining it as an over-limit condition and marking the over-limit location; it can also respond to situations where the height difference at the interface does not exceed the joint threshold, determining that the height difference at the interface meets the standard and has no over-limit defects. In one example, the joint threshold is 0.3mm. When the height difference at the interface between the subrail and the switching rail is 0.301mm, it is determined that the height difference at the interface exceeds the limit, and the above information is marked, along with the (x, y) and height difference value. Maintenance personnel can then grind or replace the protruding area and re-check the height difference. Further, it determines whether the protruding area is located on the subrail or the switching rail. It determines the relationship between the subrail's lower surface compensation distance and the switching rail's surface compensation distance. If the subrail's lower surface compensation distance is greater than the switching rail's surface compensation distance, the protruding area is located on the subrail's lower surface; if the subrail's lower surface compensation distance is less than the switching rail's surface compensation distance, the protruding area is located on the switching rail's surface.

[0029] This method 300 can also save the above sampling point data and markers in the data processing module and upload them to the system. The system generates a visualized flatness curve for each cross-section, with different colors used to mark qualified points (e.g., green), out-of-limit points (e.g., red), and critical points (e.g., yellow). When out-of-limit data occurs, the system can automatically pop up an alarm window, displaying the out-of-limit location, deviation value, out-of-limit type, and travel segment, to assist maintenance personnel in performing targeted track maintenance.

[0030] Figure 4 A schematic diagram of a height difference detection process 400 at the interface between the four-way rack subrail and the exchange rail, according to some embodiments of this disclosure, is shown. Figure 4 As shown, in box 402, the process 400 includes detecting the flatness of the lower rail surface of the subrail. In box 404, the process 400 includes determining whether the flatness of the lower rail surface of the subrail is qualified. If it is, then proceed to box 406 to perform a height difference detection at the interface between the subrail and the exchange rail. If not, then maintain the flatness of the lower rail surface of the subrail to address the flatness issue, and then return to box 402 to detect the flatness of the lower rail surface of the subrail again.

[0031] This method not only allows for the detection of the flatness of the subrail surface and the height difference at the subrail-to-rail interface by observing the four-way vehicle moving linearly on the subrail and the exchange rail, but also enables the detection of the height difference at the rail interface by first determining the flatness of the subrail surface and then checking the height difference. This height difference detection method is based on valid measurement data collected at the rail interface and can reliably detect the height difference. Maintenance personnel then only need to fine-tune the height of the exchange rail or perform localized grinding on the rail surface at the interface. If the flatness of the subrail surface is determined to be substandard, there is no need to check the height difference at the rail interface. This saves computational resources and inspection time, and avoids misjudgments of the cause of non-compliance with height differences, preventing the inability to perform targeted rail maintenance.

[0032] To facilitate understanding, a specific testing example is provided (the number of sampling points described below is not the actual number; only a portion of the sampling points are shown as examples). Assume the first cross-sectional data is collected at travel coordinate value y1, the second cross-sectional data is collected at travel coordinate value y2, and the widths of the subrail's lower rail surface and the reversing rail surface (e.g., ...) are... Figure 1 Both d1 and d2 are 53mm. The collected vehicle attitude data includes pitch angle = 0.2° and roll angle = 0.1°. Five evenly distributed lateral coordinate values ​​were selected, and the second laser detector collected the relevant ranging, compensated ranging, and ranging deviation as shown in the table below.

[0033] Table 1: Record of relevant data at the interface between the subrail and the exchange rail

[0034]

[0035] According to Table 1, the maximum value among the 5 points is taken as the final elevation difference at the interface between the sub-rail and the exchange rail: When the seam threshold is 0.3mm, If the height difference is less than the joint threshold, then the height difference at the interface between the subrail and the exchange rail meets the standard, indicating an excessive defect. Based on this method, height difference detection is performed on the interfaces between all subrails and exchange rails within the warehousing system.

[0036] Furthermore, the aforementioned subrail lower surface flatness detection process is also based on multi-sampling point detection. In some implementations, the subrail lower surface flatness detection process includes acquiring multiple frames of subrail lower cross-sectional data and multiple sets of subrail tilt angle data collected by the four-way vehicle during the subrail's travel distance. A single frame of subrail lower cross-sectional data includes multiple lateral coordinate values ​​of the subrail lower track and multiple actual distance measurements of the subrail lower surface collected at each lateral coordinate of the subrail lower track. The single frame of subrail lower cross-sectional data is collected at the corresponding travel coordinate value at each acquisition time point as the four-way vehicle travels. A single set of subrail tilt angle data includes a second pitch angle and a second roll angle. In some examples, the four-way vehicle travels unloaded on the subrail at a speed v, and the second laser detector collects a single frame of subrail lower cross-sectional data every t time. Figure 1 Taking the coordinate system as an example, it can be seen that the corresponding travel coordinate value y = v*n*t for each acquisition moment of the four-way vehicle is y = v*n*t, where n is the acquisition moment number. The single-frame sub-rail cross-sectional data for each acquisition moment includes multiple sets of data composed of the sub-rail lateral coordinate value x and the actual sub-rail distance z acquired by the second laser detector. The sub-rail travel distance l, the travel coordinate value ∈ [0, l], the sub-rail lateral coordinate value ∈ [0, d1], where d1 is the upper rail width of a single track (see...). Figure 1 There are m acquisition times, and each acquisition time includes n sets of distance measurements in the single-frame subrail cross-sectional data. Thus, all acquisition times have n*m ​​sets of distance measurements. Each acquisition time also corresponds to a set of subrail inclination angle data, resulting in m sets of subrail inclination angle data across all acquisition times. Furthermore, the inertial measurement module can acquire triaxial acceleration and triaxial angular velocity. The data processing module can then use a Kalman filter algorithm for smoothing, filtering the triaxial acceleration and angular velocity to remove instantaneous vibration interference. The filtered data serves as auxiliary verification data. If the vibration exceeds the vibration threshold, the relevant inclination angle and cross-sectional data are abnormal, requiring the removal of abnormal measurements or re-detection. If the vibration does not exceed the vibration threshold, the vehicle is considered to be traveling stably in all four directions without severe bumps, and the detection data can be used for flatness detection.

[0037] The flatness detection process of the lower rail surface of this subrail also includes determining multiple subrail lower rail surface compensation distance measurements corresponding to the transverse coordinate values ​​of each subrail based on a single frame of subrail lower cross-sectional data and a single set of subrail inclination angle data collected at the same time. The compensation formula is used (see...). Figure 3(Example formula) Corrects all range z-points. Multiplies the actual range measured by the laser detector at the current vehicle attitude by the cosine of the second pitch angle and the cosine of the second roll angle.

[0038] The subrail surface flatness detection process also includes determining the flatness of the subrail surface for each travel segment based on multiple travel coordinate values ​​for each travel segment within the subrail's running path, multiple corresponding subrail lateral coordinate values, and multiple corresponding subrail surface compensation distance measurements. In one example, based on multiple travel coordinate values ​​for each travel segment within the subrail's running path, multiple corresponding subrail lateral coordinate values, and multiple corresponding subrail surface compensation distance measurements, a least-squares fitting algorithm is used to determine the subrail reference plane fitting equation for each travel segment. Assuming the subrail reference plane fitting equation is Z = aX + bY + c, where a is the track lateral inclination coefficient, b is the track elevation slope coefficient, and c is the reference height intercept. Based on n*m sets of data within each travel segment, the optimal coefficients a, b, and c are solved using the criterion of minimizing the sum of distances from all points to the plane. Finally, the fitting equation for the subrail lower track reference plane containing optimal coefficients a, b, and c is obtained. Then, based on multiple travel coordinate values ​​for each travel segment within the subrail's running distance, multiple corresponding subrail lower track lateral coordinate values, and multiple corresponding subrail lower track surface compensation distance measurements, the lower track surface deviation is calculated using the lower track surface deviation formula. This formula is based on the difference between the fitting equation for the subrail lower track reference plane for each travel segment and the subrail lower track surface compensation distance measurement. Assume the subrail deviation formula is... Substituting the data from multiple single-frame sections of each travel segment into the aforementioned lower rail surface deviation formula yields n lower rail surface ranging deviations. Finally, based on the maximum and minimum lower rail surface ranging deviations within each travel segment, the flatness of the lower rail surface for each segment is determined. For example, the maximum and minimum lower rail surface ranging deviations are determined from the n deviations. The flatness of the lower rail surface for each travel segment is the difference between the maximum and minimum lower rail surface ranging deviations.

[0039] The subrail surface flatness detection process also includes determining that the subrail surface flatness is qualified if the flatness of the subrail surface does not exceed the segment flatness threshold in all travel segments. If the flatness of the subrail surface in one travel segment is unqualified, targeted maintenance of the track is required, and measurements are repeated until the flatness of the subrail surface in all travel segments is qualified. The flatness judgment process for the subrail surface of each travel segment is as follows: if the flatness of the subrail surface of each travel segment does not exceed the segment flatness threshold, the flatness of the subrail surface of that travel segment is qualified; alternatively, if the flatness of the subrail surface of each travel segment exceeds the segment flatness threshold, it is judged as exceeding the limit, and the position of exceeding the limit is located within each travel segment. The relationship between the fitted distance measurement and the subrail compensation distance measurement in the multi-frame cross-sectional data within the travel segment is further judged to determine whether there are depressions or protrusions on the upper and lower rail surfaces of the subrail, and these are marked and the exceeding values ​​are recorded. Accurately mark the locations of the out-of-limit points, including recording the cross section where the out-of-limit point is located (e.g., recording the travel coordinate value y), recording the lateral coordinate value x of the track under the sub-track and its corresponding out-of-limit type (e.g., depression or bulge) and out-of-limit value.

[0040] In this way, by densely collecting m×n sampling points within a single travel segment and fitting an ideal reference plane using the least squares method, it is possible to measure track flatness that more accurately reflects the microscopic undulations and macroscopic deformations of the track surface. Furthermore, dividing the track into multiple travel segments can fully account for the local characteristics of track deviations.

[0041] To facilitate understanding, the calculation process of the lower rail surface flatness in the first travel segment is used as an example (the number of sampling points described below is not the actual number; only a portion of the sampling points are shown as examples). Assume the subrail's travel distance is 20mm, divided into 20 segments, meaning each segment is 1m long. The width of the lower rail surface is 37mm. Cross-sectional data is collected at 5 longitudinal sections within each travel segment. Taking the first travel segment as an example, the travel coordinate values ​​of the 5 longitudinal sections are 0.1m, 0.3m, 0.5m, 0.7m, and 0.9m, fully covering the 0-1 meter range to avoid missed detections in single-section inspections. Five points are taken for the transverse coordinate values ​​of the lower rail under each longitudinal section: 0.2mm, 9.2mm, 18.2mm, 27.2mm, and 36.2mm. The tilt angle data collected at multiple moments within the first travel segment are essentially the same; for ease of calculation, the pitch angle is uniformly set to 0.2°, and the roll angle to 0.1°. The compensation distance measurement of the rail surface under the rail is calculated based on the transverse coordinate values ​​of the rail under the rail of different cross sections according to the compensation formula (see Table 1).

[0042] Table 1: Multi-frame cross-sectional data of multiple longitudinal sections of the track under the sub-track.

[0043]

[0044] Based on the 25 sets of data for each travel segment in Table 1, and using the minimum sum of distances from all points to the plane as the criterion, the optimal coefficients a, b, and c are solved to obtain the fitting equation for the reference plane of the sub-track: Z i = -0.00004X i +0.000002×Y i +120.016. Correspondingly, the formula for the lower rail surface deviation is: According to the lower rail surface deviation formula, the lower rail surface distance measurement deviation at different sampling points under each cross section can be obtained (see Table 2).

[0045] Table 2: Distance Measurement Deviation of Lower Rail Surface under Multiple Longitudinal Sections of the Sub-rail

[0046]

[0047] By iterating through all the deviation data of 25 sampling points across 5 sections in the first travel segment, the maximum upper rail surface distance measurement deviation was determined to be 0.0166 mm and the minimum upper rail surface distance measurement deviation was determined to be 0.0020 mm. Finally, the flatness of the lower rail surface in the first travel segment was calculated to be 0.0166 - 0.0020 = 0.0146 mm / m.

[0048] Finally, the relationship between the flatness of the lower rail surface of the first travel segment and the segment flatness threshold is determined to ascertain whether the flatness of the lower rail surface of the first travel segment is acceptable. For example, if 0.0146 mm / m is less than 0.5 mm / m, it is considered acceptable.

[0049] Figure 5 A schematic diagram of a height difference detection process 500 at the interface between the four-way rack subrail and the exchange rail, according to other embodiments of this disclosure, is shown. Figure 5 As shown, in box 502, process 500 includes detecting the flatness of the lower rail surface of the subrail. In box 504, process 500 includes detecting the flatness of the exchange rail surface. In box 506, process 500 includes determining whether the flatness of the lower rail surface of the subrail and the flatness of the exchange rail are both qualified. If yes, proceed to box 508 to perform a height difference detection at the interface between the subrail and the exchange rail. If not, maintain the flatness of the lower rail surface of the subrail for the subrail flatness problem, or maintain the flatness of the exchange rail for the exchange rail surface problem, or maintain both the subrail and the exchange rail. After maintenance, return to boxes 502 and 504 to detect the flatness of the cabinet surface of the subrail or the exchange rail.

[0050] This method first determines the flatness of the subrail and the exchange rail, then checks the height difference at the rail interface. This height difference detection method uses reliable measurement data collected at the rail interface for calculation, allowing maintenance personnel to fine-tune the exchange rail height or perform localized grinding on the rail surface at the interface. If the flatness of the subrail and / or the exchange rail is found to be substandard, height difference detection at the rail interface is unnecessary. This saves computational resources and inspection time, and avoids misjudgments of the cause of non-compliance with height differences, preventing targeted rail maintenance.

[0051] Furthermore, the embodiments of this disclosure also include a process for detecting the flatness of the lower rail surface of the subrail, which can be referred to as follows: Figure 4 An example of a flatness detection process. This disclosure also includes a track surface flatness detection process for the switching rail. In some implementations, this process includes acquiring multiple frames of switching rail cross-sectional data and multiple sets of switching rail tilt angle data collected by the four-way vehicle during its travel distance on the switching rail. A single frame of switching rail cross-sectional data includes multiple lateral coordinate values ​​of the switching rail track and multiple actual track surface distance measurements collected at each lateral coordinate of the switching rail track. The single frame of switching rail cross-sectional data is collected at the corresponding travel coordinate value at each acquisition time point as the four-way vehicle travels. A single set of switching rail tilt angle data includes a third pitch angle and a third roll angle. In some examples, the four-way vehicle travels unloaded on the switching rail at a speed v, and a second laser detector collects a single frame of switching rail cross-sectional data every t time. Figure 1 Taking the coordinate system as an example, the corresponding travel coordinate value y = v*n*t for each acquisition moment of the four-way vehicle can be seen as n, where n is the acquisition moment number. The single-frame cross-sectional data of the switching track at each acquisition moment includes multiple sets of data composed of the lateral coordinate values ​​of the switching track and the actual distance measured on the switching track surface acquired by the second laser detector. The switching track travel distance L has travel coordinate values ​​∈ [0, L], and the lateral coordinate values ​​of the switching track ∈ [0, d2], where d2 is the width of a single track surface (see...). Figure 1 There are m acquisition times, and each acquisition time includes n sets of distance measurements in the single-frame exchange track cross-section data. Thus, all acquisition times have n*m ​​sets of distance measurements. Each acquisition time also corresponds to a set of exchange track tilt angle data, resulting in m sets of exchange track tilt angle data across all acquisition times. Furthermore, the inertial measurement module can acquire triaxial acceleration and triaxial angular velocity. The data processing module can then use a Kalman filter algorithm for smoothing, filtering the triaxial acceleration and angular velocity to remove instantaneous vibration interference. The filtered data serves as auxiliary verification data. If the vibration exceeds the vibration threshold, the relevant tilt angle and cross-section data are abnormal, requiring the removal of abnormal measurements or re-detection. If the vibration does not exceed the vibration threshold, the vehicle is determined to be traveling stably in all four directions without severe bumps, and the detection data can be used for flatness detection.

[0052] The track surface flatness detection process for this switching track also includes determining multiple track surface compensation distance measurements corresponding to the lateral coordinate values ​​of each switching track based on a single frame of switching track cross-sectional data and a single set of switching track inclination data collected at the same time. The compensation formula is used (see...). Figure 3 (Example formula) Corrects all range z-points. Multiplies the actual range measured by the laser detector at the current vehicle attitude by the cosine of the third pitch angle and the cosine of the third roll angle.

[0053] The track surface flatness detection process for this switching track also includes determining the track surface flatness for each travel segment based on multiple travel coordinate values, multiple lateral coordinate values ​​of the switching track corresponding to each travel coordinate value, and multiple track surface compensation distance measurements corresponding to each lateral coordinate value. In one example, firstly, based on multiple travel coordinate values, multiple lateral coordinate values ​​of the switching track corresponding to each travel coordinate value, and multiple track surface compensation distance measurements corresponding to each lateral coordinate value, the least squares fitting algorithm is used to determine the reference plane fitting equation for each travel segment. Assuming the reference plane fitting equation is Z = aX + bY + c, where a is the lateral inclination coefficient, b is the elevation slope coefficient, and c is the reference height intercept, based on n*m sets of data within each travel segment, the optimal coefficients a, b, and c are solved using the criterion of minimizing the sum of distances from all points to the plane. Finally, the reference plane fitting equation for the switching track containing the optimal coefficients a, b, and c is obtained. Subsequently, based on multiple travel coordinate values ​​for each travel segment within the switching track's operating path, multiple switching track lateral coordinate values ​​corresponding to each travel coordinate value, and multiple switching track surface compensation distance measurements corresponding to each switching track lateral coordinate value, the switching track surface deviation formula is used to calculate the switching track surface distance measurement deviation under the switching track lateral coordinate values ​​corresponding to each travel coordinate value within each travel segment. The switching track surface deviation formula is based on the difference between the switching track reference plane fitting equation for each travel segment and the switching track surface compensation distance measurement. Assume the switching track surface deviation formula is... Substituting the data from multiple single-frame sections of each travel segment into the aforementioned exchange rail surface deviation formula yields n exchange rail surface ranging deviations. Finally, based on the maximum and minimum exchange rail surface ranging deviations within each travel segment, the flatness of the exchange rail surface for each travel segment is determined. For example, the maximum and minimum exchange rail surface ranging deviations are determined from the n exchange rail surface ranging deviations. The flatness of the exchange rail surface for each travel segment is the difference between the maximum and minimum exchange rail surface ranging deviations.

[0054] Considering the discontinuities in the rail surface of the exchange rail, this embodiment further includes processing the collected cross-sectional data of the exchange rail before determining the flatness of the rail surface for each stroke segment. The front and rear sections of the exchange rail engage with the sub-rails on both sides of the main rail, respectively. Grooves are formed in the discontinuities between the front and middle sections and between the rear and middle sections, respectively, to support the main rail (see...). Figure 1 When the four-way vehicle runs on the exchange rail, the data collected when passing through discontinuities is affected by the discontinuous rail surface, and the collected data cannot accurately reflect the flatness of the exchange rail. Therefore, the rail surface flatness detection process of this disclosure also includes extracting data from the four-way vehicle's running distance within the middle section of the exchange rail from multiple frames of exchange rail cross-sectional data and multiple sets of exchange rail inclination data. This allows for the removal of data from the front and rear sections of the exchange rail, extracting only the relevant data from the middle section. Furthermore, data collected at certain times near the discontinuities in the middle section can be removed to ensure high accuracy in calculating the rail surface flatness of the exchange rail. Based on the extracted data from the middle section of the exchange rail, compensation processing is performed on the actual distance measured on the exchange rail surface, and the rail surface flatness is calculated according to the aforementioned method.

[0055] The track surface flatness detection process for this switching rail also includes determining that the track surface flatness of the switching rail is qualified if the flatness of the switching rail in all travel segments does not exceed the segment flatness threshold. If the flatness of the switching rail in one travel segment is unqualified, targeted maintenance of the track is required, and measurements are repeated until the flatness of the switching rail in all travel segments is qualified. The process for judging the flatness of the switching rail in each travel segment is as follows: if the flatness of the switching rail in each travel segment does not exceed the segment flatness threshold, the flatness of the switching rail in that travel segment is determined to be qualified; alternatively, if the flatness of the switching rail in each travel segment exceeds the segment flatness threshold, it is determined to be out of limit, and the out-of-limit location is located within each travel segment. Further analysis is conducted on the relationship between the fitted distance measurement and the switching rail surface compensation distance measurement in the multi-frame cross-sectional data within the travel segment to determine if there are depressions or protrusions on the switching rail surface, which are then marked and recorded as out-of-limit values. Accurately mark the locations of the out-of-limit points, including recording the cross section where the out-of-limit point is located (e.g., recording the travel coordinate value y), recording the transverse coordinate value x of the exchange track and its corresponding out-of-limit type (e.g., depression or bulge) and out-of-limit value.

[0056] In this way, by densely collecting m×n sampling points within a single travel segment and fitting an ideal reference plane using the least squares method, it is possible to measure track flatness that more accurately reflects the microscopic undulations and macroscopic deformations of the track surface. Furthermore, dividing the track into multiple travel segments can fully account for the local characteristics of track deviations.

[0057] While several specific implementation details are included in the foregoing discussion, these should not be construed as limiting the scope of this disclosure. Certain features described in the context of individual embodiments may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations.

[0058] Although the subject matter has been described using language specific to structural features and / or methodological logic, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are merely illustrative examples of implementing the claims.

[0059] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting the height difference at the interface between the subrail and the exchange rail of a four-way vehicle rack, characterized in that, include: The vehicle acquires first cross-sectional data, second cross-sectional data, and vehicle attitude data when the four-way vehicle passes through the interface between the subrail and the switching rail. The first cross-sectional data includes multiple lateral coordinate values ​​of the track under the subrail and multiple actual distance measurements of the track surface under the subrail collected at the lateral coordinate of the track on each subrail. The second cross-sectional data includes multiple lateral coordinate values ​​of the track on the switching rail and multiple actual distance measurements of the track surface of the switching rail collected at the lateral coordinate of the track on each switching rail. The lateral coordinate values ​​of the track under the subrail are the same as the lateral coordinate values ​​of the track on the switching rail. The vehicle attitude data includes a first pitch angle and a first roll angle. Based on the actual distance measurements of multiple subrail under rail surfaces, multiple exchange rail surfaces, and the vehicle body attitude data, the compensated distance measurements of multiple subrail under rail surfaces and multiple exchange rail surfaces are determined; and The elevation difference at the interface between the subrail and the exchange rail is determined based on the distance measurement of the rail surface compensation of multiple subrails and the distance measurement of the rail surface compensation of multiple exchange rails.

2. The method according to claim 1, characterized in that, Based on multiple subrail surface compensation distance measurements and multiple exchange rail surface compensation distance measurements, the elevation difference at the interface between the subrail and the exchange rail is determined as follows: Based on distance measurement with multiple subrail surface compensation and multiple exchange rail surface compensation, the distance measurement deviation under multiple identical lateral coordinate values ​​was determined; and The maximum ranging deviation among multiple ranging deviations is determined as the height difference at the interface between the sub-rail and the exchange rail.

3. The method according to claim 1, characterized in that, The method also includes: If the height difference at the interface between the subrail and the exchange rail exceeds the joint threshold, it is determined to be out of limit, and the out-of-limit location is marked.

4. The method according to claim 1, characterized in that, The method also includes: If the flatness of the lower rail surface of the subrail is qualified, the height difference detection process at the interface between the subrail and the exchange rail is executed.

5. The method according to claim 1, characterized in that, The method also includes: If the flatness of the lower rail surface of the subrail and the flatness of the rail surface of the exchange rail are both qualified, the height difference detection procedure at the interface between the subrail and the exchange rail is executed.

6. The method according to claim 4 or 5, characterized in that, The flatness inspection process for the lower rail surface of the subrail includes: The system acquires multiple frames of subrail under-section data and multiple sets of subrail tilt angle data collected by the four-way vehicle during its subrail running distance. Each frame of subrail under-section data includes multiple subrail under-rail lateral coordinate values ​​and multiple actual subrail under-rail surface distances collected at each subrail under-rail lateral coordinate. The single frame of subrail under-section data is collected at the corresponding travel coordinate value at each acquisition time when the four-way vehicle is running. Each set of subrail tilt angle data includes the second pitch angle and the second roll angle. Based on the single-frame subrail cross-sectional data and the single set of subrail inclination data collected at the same time, multiple subrail surface compensation distance measurements corresponding to the transverse coordinate values ​​of each subrail are determined. Based on multiple travel coordinate values ​​for each travel segment within the subrail's running path, multiple lateral coordinate values ​​of the subrail's lower track corresponding to each travel coordinate value, and multiple subrail lower track surface compensation distance measurements corresponding to each subrail lower track lateral coordinate value, the flatness of the lower track surface for each travel segment is determined; and If the flatness of the lower rail surface of all travel segments does not exceed the segment flatness threshold, the flatness of the lower rail surface of the subrail is determined to be qualified.

7. The method according to claim 6, characterized in that, Determining the flatness of the lower rail surface for each travel segment includes: Based on multiple travel coordinate values ​​of each travel segment within the subrail running distance, multiple subrail under track lateral coordinate values ​​corresponding to each travel coordinate value, and multiple subrail under track surface compensation distances corresponding to each subrail under track lateral coordinate value, the least squares fitting algorithm is used to determine the subrail under track reference plane fitting equation for each travel segment. Based on multiple travel coordinate values ​​for each travel segment within the subrail's running path, multiple subrail lower track lateral coordinate values ​​corresponding to each travel coordinate value, and multiple subrail lower track surface compensation distance measurements corresponding to each subrail lower track lateral coordinate value, the lower track surface distance measurement deviation under the subrail lower track lateral coordinate values ​​corresponding to each travel coordinate value within each travel segment is calculated using the lower track surface deviation formula. The lower track surface deviation formula is based on the difference between the subrail lower track reference plane fitting equation for each travel segment and the subrail lower track surface compensation distance measurement. The flatness of the lower rail surface in each travel segment is determined based on the maximum and minimum lower rail surface distance measurement deviations within each travel segment.

8. The method according to claim 5, characterized in that, The process for inspecting the flatness of the rail surface of the interchangeable rail includes: The system acquires multiple frames of rail cross-section data and multiple sets of rail tilt angle data collected by the four-way vehicle during its rail travel. Each frame of rail cross-section data includes multiple transverse coordinate values ​​of the rail and multiple actual distance measurements of the rail surface collected at each transverse coordinate of the rail. The single frame of rail cross-section data is collected at the corresponding travel coordinate value at each acquisition time of the four-way vehicle. Each set of rail tilt angle data includes the third pitch angle and the third roll angle. Based on the single-frame exchange rail cross-section data and the single set of exchange rail inclination data collected at the same time, multiple exchange rail surface compensation distance measurements corresponding to the transverse coordinate values ​​of each exchange rail are determined. Based on multiple travel coordinate values ​​for each travel segment within the operating distance of the switching rail, multiple lateral coordinate values ​​of the switching rail corresponding to each travel coordinate value, and multiple rail surface compensation distance measurements corresponding to each lateral coordinate value of the switching rail, the rail surface flatness of the switching rail for each travel segment is determined; and If the flatness of the rail surface of the exchange rail does not exceed the segment flatness threshold in all travel segments, the flatness of the rail surface of the exchange rail is determined to be qualified.

9. The method according to claim 8, characterized in that, Also includes: Data on the running distance of the four-way vehicle within the middle section of the switching track was extracted from the acquired multi-frame switching track cross-section data and multiple sets of switching track tilt angle data; Based on the data of the four-way vehicle within the running distance of the middle section of the exchange rail, the flatness of the exchange rail surface for each travel segment is determined.

10. The method according to claim 8, characterized in that, Determining the flatness of the interchange rails for each travel segment includes: Based on multiple travel coordinate values ​​of each travel segment within the running distance of the switching rail, multiple switching rail lateral coordinate values ​​corresponding to each travel coordinate value, and multiple switching rail surface compensation distance measurements corresponding to each switching rail lateral coordinate value, the least squares fitting algorithm is used to determine the switching rail reference plane fitting equation for each travel segment. Based on multiple travel coordinate values ​​for each travel segment within the operating path of the switching rail, multiple switching rail lateral coordinate values ​​corresponding to each travel coordinate value, and multiple switching rail surface compensation distance measurements corresponding to each switching rail lateral coordinate value, the switching rail surface distance measurement deviation under the switching rail lateral coordinate values ​​corresponding to each travel coordinate value within each travel segment is calculated using the switching rail surface deviation formula. The switching rail surface deviation formula is based on the difference between the switching rail reference plane fitting equation for each travel segment and the switching rail surface compensation distance measurement. The flatness of the exchange rail surface in each travel segment is determined based on the maximum and minimum exchange rail surface distance measurement deviations within each travel segment.

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