Railway track smoothness tangent curve measurement system and method

Abstract

The application discloses a railway track smoothness flat curve measuring system and method. The system comprises a light source device, a track measuring trolley, a detection target head and an upper computer control software; the track measuring trolley is integrated with a displacement sensor, an inclination sensor and an encoder, the detection target head is installed on the track measuring trolley and is connected with a target head transverse moving mechanism, and a pull rod type displacement sensor is arranged on the mechanism. The application proposes a smoothness measuring method for four track forms of straight line, upper curve, lower curve and horizontal curve, the track type is distinguished through the inclination sensor, a dynamic error compensation model based on the curvature radius is established to compensate the curve track measuring result, the encoder is used for mileage counting to realize defect positioning, and the pull rod type displacement sensor is used for measuring the target head transverse moving amount to correct the measuring deviation. The application can simultaneously measure track gauge, level, track direction, height and other smoothness parameters, and significantly improves the measuring precision and application range of the curve track.

Description

Technical Field

[0001] This invention relates to the field of railway track inspection technology, and more specifically, to a railway track smoothness horizontal curve measurement system and method. Background Technology

[0002] The smoothness of railway tracks is a key indicator for ensuring the safety and comfort of train operation, mainly including parameters such as track gauge, level, alignment, and elevation. Traditional manual inspection methods, such as chord measurement and string line methods, are inefficient and lack accuracy, especially in quickly locating track defects. While some existing automated track inspection equipment achieves automatic acquisition of some parameters, it is usually complex in structure, cumbersome in operation, and lacks high integration of multiple sensors, making it difficult to simultaneously and accurately measure multiple parameters such as track gauge, level, alignment, and elevation. Particularly for curved tracks, the geometric deviation between the laser reference line and the actual track centerline leads to systematic errors when directly applying measurement methods used for straight tracks, resulting in a significant decrease in measurement accuracy for curved sections. Furthermore, current technologies lack the ability to automatically identify track types and cannot adaptively adjust the measurement model for different track forms such as upper curves, lower curves, and horizontal curves, limiting their application on complex lines.

[0003] To address this, existing technologies include laser-collimated track detection devices, such as laser long-chord track smoothness detection devices, which achieve automatic acquisition of laser positions. However, these devices are primarily designed for straight tracks, failing to consider the influence of curvature on measurement results for curved tracks, and cannot simultaneously measure multiple parameters such as track gauge and level. Furthermore, existing devices rely heavily on sleeper counting for mileage positioning, but manufacturing and installation errors in sleeper spacing limit positioning accuracy. For target alignment, fixed installations are commonly used, failing to compensate for lateral target offset caused by track twisting or installation deviations. Therefore, there is an urgent need for an intelligent track smoothness measurement system and method that can adapt to various track types, possesses curvature error compensation, high-precision mileage positioning, and target lateral offset correction functions. Summary of the Invention

[0004] In view of the above-mentioned technical problems in related technologies, the present invention proposes a railway track smoothness horizontal curve measurement system and method, which can overcome the above-mentioned shortcomings of the prior art.

[0005] To achieve the above-mentioned technical objectives, the technical solution of the present invention is implemented as follows: A system for measuring the smoothness of railway track curves; The railway track smoothness horizontal curve measurement system includes: A light source device for emitting a laser beam to provide a measurement reference; A track measuring trolley is used to move along the track being measured. The track measuring trolley integrates a displacement sensor, an inclination sensor, and an encoder. The displacement sensor is used to measure the track gauge, the inclination sensor is used to measure the change in inclination angle of the track measuring trolley during movement, and the encoder is used for mileage counting to achieve defect location. A detection target head, mounted on the track-measuring trolley, is used to receive the laser beam emitted by the light source device and acquire the light spot image. The detection target head is connected to a target head lateral movement mechanism, which is equipped with a pull rod displacement sensor. The pull rod displacement sensor is used to measure the lateral movement of the target head. The host computer control software is communicatively connected to the displacement sensor, the tilt sensor, the encoder, the lever-type displacement sensor, and the detection target head. It is used to determine the track type based on the tilt angle change law measured by the tilt sensor, and to select the corresponding measurement model for different track types to process the spot image, the track gauge, the tilt angle change, and the lateral movement of the target head to calculate the track smoothness and elevation smoothness.

[0006] Furthermore, the main body of the track measuring trolley is a hollow crossbeam structure. The crossbeam is equipped with traveling wheels and auxiliary traveling wheels on both sides. The crossbeam is provided with a connecting magnetic seat for connecting the push rod in the middle. The right side of the crossbeam is equipped with the displacement sensor and a transmission mechanism linked to the displacement sensor. The left side of the crossbeam is equipped with the tilt sensor. The upper left side of the crossbeam is provided with a connecting seat for installing the detection target.

[0007] Furthermore, the tilt sensor is an XY two-dimensional measurement type, which is horizontally installed directly below the detection target head, and the X-axis installation direction of the tilt sensor is consistent with the direction of the crossbeam.

[0008] Furthermore, the light source device is equipped with a two-axis fine-tuning device, a horizontal bubble device, and an electronic display screen. The two-axis fine-tuning device is used to adjust the beam direction of the laser generator inside the light source device, and the electronic display screen is used to display the remaining power information of the light source device. In addition, the laser generator has a built-in spatial phase modulator.

[0009] Furthermore, the detection target head includes a target head shell, a light shield, a filter, a CMOS camera and lens, and an embedded development board. The filter is a 650nm single-wavelength ultra-narrowband filter. The embedded development board is used to process the acquired light spot image and the data from each sensor and wirelessly transmit them to the host computer control software. The target head lateral movement mechanism is connected to the bottom of the detection target head. The rod-type displacement sensor is set in the target head lateral movement mechanism and is used to collect the lateral displacement of the detection target head relative to the track measuring trolley crossbeam in real time.

[0010] According to another aspect of the present invention, a method for measuring the smoothness of a railway track horizontal curve is provided; The method for measuring the smoothness of railway track curves includes the following steps: Step 1, System Calibration: Fix the light source device to one end of the track to be tested, place the track measuring trolley at the other end of the track to be tested, adjust the light source device so that the laser beam emitted by it is mapped onto the target surface area of ​​the detection target head, and record the light spot coordinates at this time as the reference coordinates; Step 2, Track type determination: Push the track measuring trolley to move along the track, and monitor the tilt angle changes of the track measuring trolley in the horizontal and vertical directions in real time through the tilt angle sensor. Determine the current track type as a straight line, upper curve, lower curve or horizontal curve based on the tilt angle change law; Step 3, Data Acquisition: During the movement of the track measuring trolley, the light spot image is continuously acquired by the detection target head and the light spot coordinates are extracted. The track gauge value is measured in real time by the displacement sensor, the tilt angle of the crossbeam is measured by the tilt sensor, the movement mileage is recorded by the encoder, and the lateral movement of the target head is measured by the rod-type displacement sensor. Step 4, Curvature measurement of curved track: For sections identified as curved tracks, the radius of curvature of the current track segment is calculated based on the mileage information recorded by the encoder and the cumulative angle change measured by the tilt sensor. Step 5, Smoothness parameter calculation and compensation: Based on the identified track type and the calculated radius of curvature, combined with the lateral movement of the target head, calculate the track smoothness parameter and the elevation smoothness parameter respectively, and compensate for the curvature error of the calculated results of the curved track.

[0011] Furthermore, the method for calculating the radius of curvature in step 4 is as follows: Let the distance the track measuring trolley travels within a unit mileage be L, and the cumulative change in the horizontal direction angle measured by the tilt sensor be Δθ, then the horizontal radius of curvature R = L / Δθ; for upper or lower curved tracks, the vertical radius of curvature is calculated based on the cumulative change in the vertical direction angle.

[0012] Furthermore, step 5, the calculation and compensation of the ride comfort parameters, specifically includes: For a straight track, track smoothness High and low smoothness ,in( (x', y') are the reference coordinates, and (x', y') are the measured spot coordinates; For horizontal curved tracks, a curvature error compensation coefficient k_h = 1 + (d / 2R) is introduced, where d is the length of the track measuring trolley, R is the horizontal radius of curvature, and the compensated track smoothness is... High and low smoothness ; For tracks with upward or downward curves, a vertical curvature error compensation coefficient k_v = 1 + (d / 2R_v) is introduced, where R_v is the vertical curvature radius, and the compensated height and smoothness are... Track smoothness .

[0013] Furthermore, it also includes a track level parameter calculation step: calculating the track level parameters based on the current track gauge value W measured by the displacement sensor and the horizontal tilt angle θ_x of the crossbeam measured by the tilt sensor. .

[0014] Furthermore, the extraction of the spot coordinates adopts a sub-pixel positioning algorithm, and the pixel offset is converted into the true offset through the pixel-to-true distance conversion relationship. The conversion relationship is: true offset = pixel offset × (filter size / number of pixels corresponding to the camera field of view) × target distance coefficient; and the lateral movement of the target head is used to correct the systematic deviation in the spot coordinates.

[0015] The beneficial effects of this invention are as follows: By integrating a displacement sensor, tilt sensor, encoder, and target head lateral movement mechanism with a lever-type displacement sensor into the track measuring trolley, and establishing a dynamic error compensation model based on the radius of curvature, the system can automatically identify track types such as straight lines, upper curves, lower curves, and horizontal curves, and perform targeted curvature error compensation. Simultaneously, the encoder achieves high-precision mileage positioning, and the lever-type displacement sensor corrects the lateral offset of the target head, thereby achieving the effect of simultaneously and accurately measuring multiple smoothness parameters such as track gauge, level, track orientation, and elevation. This significantly improves the measurement accuracy and applicability of curved tracks, simplifies the operation process, and provides an efficient and accurate technical means for the daily inspection and maintenance of railway tracks. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a measurement flowchart of a railway track smoothness horizontal curve measurement system and method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the principle of measuring the smoothness of a straight track according to an embodiment of the present invention, which describes a railway track smoothness horizontal curve measurement system and method. Figure 3This is a schematic diagram illustrating the principle of a horizontal curve track smoothness measurement system and method according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] A railway track smoothness horizontal curve measurement system according to an embodiment of the present invention includes: A light source device for emitting a laser beam to provide a measurement reference; A track measuring trolley is used to move along the track being measured. The track measuring trolley integrates a displacement sensor, an inclination sensor, and an encoder. The displacement sensor is used to measure the track gauge, the inclination sensor is used to measure the change in inclination angle of the track measuring trolley during movement, and the encoder is used for mileage counting to achieve defect location. A detection target head, mounted on the track-measuring trolley, is used to receive the laser beam emitted by the light source device and acquire the light spot image. The detection target head is connected to a target head lateral movement mechanism, which is equipped with a pull rod displacement sensor. The pull rod displacement sensor is used to measure the lateral movement of the target head. The host computer control software is communicatively connected to the displacement sensor, the tilt sensor, the encoder, the lever-type displacement sensor, and the detection target head. It is used to determine the track type based on the tilt angle change law measured by the tilt sensor, and to select the corresponding measurement model for different track types to process the spot image, the track gauge, the tilt angle change, and the lateral movement of the target head to calculate the track smoothness and elevation smoothness.

[0020] According to an embodiment of the present invention, a railway track smoothness horizontal curve measurement system is provided. In a specific embodiment, the main body of the track measuring trolley is a hollow crossbeam structure. The crossbeam is equipped with traveling wheels and auxiliary traveling wheels on both sides. A connecting magnetic seat for connecting a push rod is provided in the middle of the crossbeam. The right side of the crossbeam is equipped with the displacement sensor and a transmission mechanism linked to the displacement sensor. The left side of the crossbeam is equipped with the tilt sensor. A connecting seat for mounting the detection target head is provided on the upper left side of the crossbeam.

[0021] According to an embodiment of the present invention, a railway track smoothness horizontal curve measurement system is provided. In a specific embodiment, the tilt sensor is an XY two-dimensional measurement type, which is horizontally installed directly below the detection target head, and the X-axis installation direction of the tilt sensor is consistent with the direction of the crossbeam.

[0022] According to an embodiment of the present invention, a railway track smoothness horizontal curve measurement system is provided. In a specific embodiment, the light source device is provided with a two-axis fine adjustment device, a horizontal bubble device, and an electronic display screen. The two-axis fine adjustment device is used to adjust the beam direction of the laser generator inside the light source device, and the electronic display screen is used to display the remaining power information of the light source device. Furthermore, the laser generator has a built-in spatial phase modulator.

[0023] According to an embodiment of the present invention, a railway track smoothness horizontal curve measurement system includes, in a specific embodiment, a detection target head comprising a target head shell, a light shield, a filter, a CMOS camera and lens, and an embedded development board. The filter is a 650nm single-wavelength ultra-narrowband filter. The embedded development board is used to process the acquired spot image and data from various sensors and wirelessly transmit them to the host computer control software. The target head lateral movement mechanism is connected to the bottom of the detection target head, and the rod-type displacement sensor is disposed within the target head lateral movement mechanism for real-time acquisition of the lateral displacement of the detection target head relative to the track measuring trolley crossbeam.

[0024] Secondly, according to an embodiment of the present invention, a method for measuring the smoothness of a railway track curve includes the following steps: Step 1, System Calibration: Fix the light source device to one end of the track to be tested, place the track measuring trolley at the other end of the track to be tested, adjust the light source device so that the laser beam emitted by it is mapped onto the target surface area of ​​the detection target head, and record the light spot coordinates at this time as the reference coordinates; Step 2, Track type determination: Push the track measuring trolley to move along the track, and monitor the tilt angle changes of the track measuring trolley in the horizontal and vertical directions in real time through the tilt angle sensor. Determine the current track type as a straight line, upper curve, lower curve or horizontal curve based on the tilt angle change law; Step 3, Data Acquisition: During the movement of the track measuring trolley, the light spot image is continuously acquired by the detection target head and the light spot coordinates are extracted. The track gauge value is measured in real time by the displacement sensor, the tilt angle of the crossbeam is measured by the tilt sensor, the movement mileage is recorded by the encoder, and the lateral movement of the target head is measured by the rod-type displacement sensor. Step 4, Curvature measurement of curved track: For sections identified as curved tracks, the radius of curvature of the current track segment is calculated based on the mileage information recorded by the encoder and the cumulative angle change measured by the tilt sensor. Step 5, Smoothness parameter calculation and compensation: Based on the identified track type and the calculated radius of curvature, combined with the lateral movement of the target head, calculate the track smoothness parameter and the elevation smoothness parameter respectively, and compensate for the curvature error of the calculated results of the curved track.

[0025] According to an embodiment of the present invention, a method for measuring the smoothness of a railway track on a horizontal curve, in a specific embodiment, the method for calculating the radius of curvature in step 4 is as follows: let the distance the track measuring trolley travels within a unit mileage be L, and the cumulative change in the horizontal direction angle measured by the tilt sensor be Δθ, then the horizontal radius of curvature R = L / Δθ; for upper or lower curve tracks, the vertical radius of curvature is calculated based on the cumulative change in the vertical direction angle.

[0026] According to an embodiment of the present invention, a method for measuring the smoothness of a railway track curve, in a specific implementation, step 5, the calculation and compensation of the smoothness parameters, specifically includes: For a straight track, track smoothness High and low smoothness ,in( (x', y') are the reference coordinates, and (x', y') are the measured spot coordinates; For horizontal curved tracks, a curvature error compensation coefficient k_h = 1 + (d / 2R) is introduced, where d is the length of the track measuring trolley, R is the horizontal radius of curvature, and the compensated track smoothness is... High and low smoothness ; For tracks with upward or downward curves, a vertical curvature error compensation coefficient k_v = 1 + (d / 2R_v) is introduced, where R_v is the vertical curvature radius, and the compensated height and smoothness are... Track smoothness .

[0027] According to an embodiment of the present invention, a method for measuring the smoothness of a railway track curve includes, in a specific implementation, a track horizontal parameter calculation step: calculating the track horizontal parameter H = W × sinθ_x based on the current track gauge value W measured by the displacement sensor and the horizontal inclination angle θ_x of the crossbeam measured by the inclination sensor.

[0028] According to an embodiment of the present invention, a method for measuring the smoothness of a railway track curve is provided. In a specific implementation, the extraction of the spot coordinates employs a sub-pixel positioning algorithm, and the pixel offset is converted into the true offset through a pixel-to-true distance conversion relationship. The conversion relationship is: true offset = pixel offset × (filter size / number of pixels corresponding to the camera field of view) × target distance coefficient; and the lateral movement of the target head is used to correct the systematic deviation in the spot coordinates.

[0029] To facilitate understanding of the above technical solutions of the present invention, the following detailed description of the above technical solutions of the present invention is provided through specific embodiments and working principles.

[0030] Example 1: System Structure and Working Principle This embodiment describes the specific structure of the measurement system of the present invention and the principle of the synergistic effect of each component.

[0031] The railway track smoothness horizontal curve measurement system provided by this invention includes a light source device, a track measuring trolley, a detection target head, and upper computer control software. The main body of the track measuring trolley is a hollow crossbeam structure, with traveling wheels and auxiliary traveling wheels mounted on both sides of the crossbeam to ensure stable operation of the trolley on the track. A connecting magnetic base for connecting a push rod is located in the middle of the crossbeam; the push rod can be attracted to the connecting magnetic base, facilitating the operator to push the trolley.

[0032] A displacement sensor and a transmission mechanism are installed on the right side of the crossbeam. Its working principle is as follows: when the track gauge changes, the right-side auxiliary traveling wheel drives the transmission mechanism to press against the displacement sensor. This displacement sensor is a sliding probe type with a measuring range of 0~75mm, capable of accurately measuring changes in track gauge.

[0033] An inclination sensor is mounted on the left side of the crossbeam. The inclination sensor is an XY two-dimensional measurement type, horizontally mounted directly below the detection target, with its X-axis aligned with the crossbeam. It is used to measure the changes in the track's inclination angle in both the horizontal and vertical directions.

[0034] Compared to traditional sleeper counting methods, encoder mileage counting is not affected by sleeper spacing manufacturing errors, has higher positioning accuracy, and can achieve precise mileage location of track defects.

[0035] A connecting seat is located on the upper left side of the crossbeam, and the detection target head is mounted on the connecting seat via a target head lateral movement mechanism. This mechanism is a precision linear sliding module with a pull-rod type displacement sensor inside. The detection target head can translate laterally along the crossbeam (perpendicular to the track extension direction) under the action of this mechanism. The pull-rod type displacement sensor is used to measure the lateral movement of the detection target head relative to the crossbeam in real time. Its working principle is as follows: In actual measurements, due to track distortion, installation errors, or changes in the carriage's attitude on curved sections, the centerline of the detection target head may not always be aligned with the ideal position of the laser beam. By actively or passively adjusting the target head lateral movement mechanism, the laser spot is kept on the target surface. Simultaneously, the pull-rod type displacement sensor records the lateral offset of the target head, which is used for subsequent correction of the laser spot coordinates, eliminating measurement errors introduced by target head alignment deviations.

[0036] The detection target head is an integrated structure, comprising a target head shell, a light shield, a filter, a CMOS camera and lens, an embedded development board, a battery, and a switch button. The filter is a 650nm single-wavelength ultra-narrowband filter, which works by allowing only light with a wavelength close to the laser wavelength (650nm) emitted by the light source to pass through, effectively filtering ambient light interference and ensuring a clear light spot image. The CMOS camera and lens are used to acquire light spot images. The embedded development board processes the images in real time and reads data from the displacement sensor, tilt sensor, encoder, and lever-type displacement sensor, packaging them together and transmitting them wirelessly to the host computer control software.

[0037] The light source device is a standalone unit, comprising a laser generator, an electronic display screen, and a horizontally fixed base. The device features a two-axis fine-tuning mechanism for the laser generator, allowing precise adjustment of the laser beam direction to ensure direct illumination of the target surface of the detection head. The electronic display screen shows the remaining battery power of the light source device. The laser generator incorporates a spatial phase modulator, which works by improving the wavefront quality of the laser beam, thereby enhancing its stability and resistance to atmospheric disturbances.

[0038] Example 2: Measurement Method and Dynamic Compensation Principle This embodiment uses a complex route with a length of 200m, including a straight section, a horizontal curve section (R=300m), and an uphill curve section (R=500m), as an example to explain in detail the measurement process and curvature error compensation principle of the present invention.

[0039] Step 1: System Calibration The light source device is horizontally fixed to one end of the track to be tested (start point O) using a horizontal base, and the track measuring trolley is placed at the other end of the track (end point A). The power to the light source device and the detection target head is turned on, and the image of the light spot acquired by the detection target head is viewed in real time through the host computer control software. The two-axis fine-tuning device of the light source device is adjusted so that the laser beam is vertically mapped onto the area of ​​the filter on the detection target head. At this time, the detection target head is adjusted to the middle stroke position through the target head lateral movement mechanism, and the reading of the lever-type displacement sensor is recorded as the lateral zero position. Simultaneously, the host computer control software records the light spot coordinates as the reference coordinates. Pixels (pixels), and mark point A, where the track measuring trolley is located, as the calibration point (mileage zero point).

[0040] Step 2: Track type identification The operator pushes the track-measuring trolley from point A to point O at a speed of approximately 0.5 m / s. During this movement, the tilt sensor monitors the tilt angle changes of the crossbeam in the horizontal (X-axis) and vertical (Y-axis) directions in real time at a sampling frequency of 50 Hz. The host computer control software receives the tilt angle data in real time and performs analysis. In the initial section (0~50m), the tilt sensor data showed that θ_x was stable at 0.01°±0.01° and θ_y was stable at 0.02°±0.01°, indicating that it was a straight track.

[0041] In the middle section (50~120m), the data shows that the horizontal inclination angle θ_x changes continuously in one direction, with a cumulative change rate of about 0.057° / m, while the vertical inclination angle θ_y remains constant, which is identified as a horizontal curved track.

[0042] In the latter part (120~200m), the data shows that the vertical inclination angle θ_y changes continuously in the positive direction, with a cumulative change rate of about 0.069° / m, while the horizontal inclination angle θ_x remains constant, which is identified as an upper curve track.

[0043] Its operating principle is as follows: On a straight track, the attitude angle of the trolley's crossbeam remains essentially constant; on a horizontally curved track, due to the track's curvature in the horizontal plane, the horizontal inclination angle of the crossbeam continuously changes unidirectionally as the trolley moves along the curve; on an upper or lower curved track, due to the slope change in the vertical plane, the vertical inclination angle of the trolley continuously changes. By monitoring the changes in these two inclination angles in real time, the system can automatically determine the current track type, providing a basis for subsequently selecting the appropriate measurement model.

[0044] Step 3: Data Acquisition and Spot Coordinate Extraction During the movement of the track-tracking trolley, the detection target continuously acquires light spot images at a frequency of 20Hz. The embedded development board uses a sub-pixel positioning algorithm to extract the light spot coordinates. This algorithm first obtains the coordinates of the light spot using the gray-scale centroid method, and then performs sub-pixel subdivision of the coordinates using a surface fitting method, achieving a coordinate positioning accuracy within 0.1 pixels. The extracted light spot coordinates are (x', y').

[0045] Simultaneously, the displacement sensor measures the track gauge value W in real time, the tilt sensor measures the horizontal tilt angle θ_x and the vertical tilt angle θ_y of the crossbeam, the encoder records the movement mileage S in real time, and the rod-type displacement sensor measures the lateral movement amount Δx_target of the target head in real time.

[0046] Step 4: Curvature Measurement of Curved Track For sections identified as curved tracks, the system automatically enters curvature measurement mode. Its operating principle is as follows: As the track-measuring trolley moves along a curved track, its direction of travel constantly changes due to the track's curvature. This causes the horizontal (or vertical) tilt angle measured by the tilt sensor to cumulatively change with the distance traveled. By recording the mileage information from the encoder, the distance L traveled by the trolley within a certain mileage interval can be accurately determined. Simultaneously, the cumulative angle change Δθ measured by the tilt sensor over this distance is recorded. According to geometric relationships, the radius of curvature R = L / Δθ (where Δθ is in radians).

[0047] In the horizontal curve segment (50~120m) of this embodiment, the measurements from 10 consecutive mileage intervals (each interval 1m) are averaged to reduce random errors. The calculated horizontal radius of curvature R_h = 305m, which is very close to the design value of 300m. In the upper curve segment (120~200m), the vertical radius of curvature R_v = 510m is calculated using the same method, which is close to the design value of 500m.

[0048] Step 5: Smoothness parameter calculation and curvature error compensation (including target head lateral movement correction) The system automatically selects the appropriate measurement model and applies curvature error compensation based on the identified track type and calculated radius of curvature. Simultaneously, it corrects the spot coordinates using the lateral movement Δx_target of the target head measured by a lever-type displacement sensor.

[0049] The corrected spot coordinates are: x'' = x' - Δx_target (pixels or the converted true value). Its working principle is as follows: when the target head's lateral movement mechanism adjusts the position of the detection target, the spot coordinates in the camera's field of view will have an additional offset. This offset is not caused by track smoothness, but by the target head's active adjustment. This adjustment is accurately recorded by a lever-type displacement sensor and subtracted during calculation, eliminating measurement interference introduced by the target head's alignment operation and ensuring that the measurement results accurately reflect the track's geometric state.

[0050] (1) Principles and calculations of horizontal and straight track measurement On a straight track, track smoothness High and low smoothness (The y-direction usually does not require lateral correction of the target head, but if the lateral movement mechanism of the target head has a vertical adjustment function, then the same treatment applies).

[0051] At point P on a straight line segment in this embodiment, the measured coordinates of the light spot are (x'=325 pixels, y'=243 pixels). The lever-type displacement sensor measures Δx_target=0.5mm, which, converted to pixel equivalent (horizontal conversion coefficient 0.015625mm / pixel), yields Δx_target_pixel=32 pixels. Therefore, after correction, x''=325-32=293 pixels. (Baseline) If the pixel value is Δx, then Δx = (293-320) × 0.015625 = -0.422mm. The actual trajectory deviation is -0.422mm (the negative sign indicates a deviation to the other side). If not corrected, it will be misjudged as Δx = (325-320) × 0.015625 = 0.078mm, leading to an error.

[0052] (2) Measurement principle and compensation of horizontal curve track For horizontal curved tracks, the compensation coefficient k_h = 1 + d / (2R_h). The corrected track alignment smoothness... Smoothness at varying heights .

[0053] At point Q on the horizontal curve segment in this embodiment, the coordinates of the light spot are measured (x'=350 pixels, y'=241 pixels), Δx_target=0.3mm (corresponding to 19.2 pixels), and after correction, x''=350-19.2=330.8 pixels. Δx_raw=(330.8-320)×0.015625=0.16875mm. d=800mm, R_h=305000mm, k_h=1.001311, and after compensation, Δx=0.16875×1.001311=0.1690mm. Δy=(241-240)×0.020833=0.0208mm.

[0054] (3) Measurement principle and compensation of upper curve track For an upward-curved track, the compensation coefficient k_v = 1 + d / (2R_v) represents the elevation smoothness after compensation. Track smoothness (If there is no curvature in the horizontal direction).

[0055] Step 6: Calculation of Track Horizontal Parameters Based on the current track gauge value W measured by the displacement sensor and the horizontal inclination angle θ_x of the crossbeam measured by the tilt sensor, the track horizontal parameter H = W × sinθ_x is calculated. This parameter reflects the height difference between the left and right rails on the same cross section of the track.

[0056] Step 7: Defect Location The mileage S recorded by the encoder corresponds to the mileage marker on the track. When the track alignment smoothness Δx, elevation smoothness Δy, or horizontal parameter H at a certain measurement point exceeds a preset threshold, the host computer control software records the current mileage value S, achieving precise mileage location of the defect. For example, when Δx at mileage K35+126 is detected to reach 0.8mm (exceeding the threshold of 0.5mm), the system immediately alarms and prompts "track alignment error exists near K35+126".

[0057] Step 8: Host computer display and data output The host computer control software displays real-time curves showing the changes in parameters such as track alignment, elevation, gauge, and level with mileage, in the form of graphs. It also displays information such as the current track type, radius of curvature, and lateral movement of the target head. After measurement, the software automatically generates a track smoothness inspection report, including the location and value of any out-of-tolerance parameters, facilitating on-site handling by maintenance personnel.

[0058] Example 3: Verification of the function of the target head lateral movement mechanism To verify the necessity of the target lateral movement mechanism and the lever-type displacement sensor, a comparative test was conducted on a straight track. The light source was fixed, and the track-measuring trolley was placed on the track, allowing the laser beam to strike the target surface of the probe. The probe was manually moved 2.0 mm to the right using the lateral movement mechanism. At this point, the lever-type displacement sensor displayed Δx_target = 2.0 mm. Without correction, the host computer displayed a leftward shift of the light spot coordinates by approximately 2.0 mm, corresponding to 128 pixels, which was mistakenly interpreted as a track deviation of 2.0 mm. However, after enabling the correction function, the system automatically subtracted the lateral movement of the target from the light spot coordinates, displaying an actual track deviation of 0.0 mm. This demonstrates that the mechanism effectively eliminates lateral offset interference caused by target alignment adjustments or external vibrations, ensuring the accuracy of the measurement results.

[0059] Example 4: Compensation effect of small radius curved tracks Measurements were conducted on a horizontal curved track with a radius of R = 150m. The track-measuring trolley was d = 800mm long, and the theoretical compensation coefficient k_h = 1.002667. At a certain point, a high-precision total station measured the actual track alignment deviation to be 2.500mm. After correction by a lever-type displacement sensor, the probe head obtained x'', and the calculated Δx_raw = 2.493mm. After compensation, Δx = 2.493 × 1.002667 = 2.4996mm, with a measurement error of only -0.0004mm, significantly higher than the uncompensated 2.493mm (error -0.007mm). Simultaneously, the mileage recorded by the encoder was compared with the actual mileage marker, showing an error of less than 0.1%, indicating accurate positioning.

[0060] In summary, by utilizing the technical solution of this invention, and integrating a displacement sensor, tilt sensor, encoder, and a target head lateral movement mechanism with a lever-type displacement sensor into the track measuring trolley, and establishing a dynamic error compensation model based on the radius of curvature, the system can automatically identify track types such as straight lines, upper curves, lower curves, and horizontal curves, and perform targeted curvature error compensation. Simultaneously, the encoder achieves high-precision mileage positioning, and the lever-type displacement sensor corrects the lateral offset of the target head, thereby achieving the effect of simultaneously and accurately measuring multiple smoothness parameters such as track gauge, level, track orientation, and elevation. This significantly improves the measurement accuracy and applicability of curved tracks, simplifies the operation process, and provides an efficient and accurate technical means for the daily inspection and maintenance of railway tracks.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A system for measuring the smoothness of railway track curves, characterized in that, include: A light source device for emitting a laser beam to provide a measurement reference; A track measuring trolley is used to move along the track being measured. The track measuring trolley integrates a displacement sensor, an inclination sensor, and an encoder. The displacement sensor is used to measure the track gauge, the inclination sensor is used to measure the change in inclination angle of the track measuring trolley during movement, and the encoder is used for mileage counting to achieve defect location. A detection target head, mounted on the track-measuring trolley, is used to receive the laser beam emitted by the light source device and acquire the light spot image. The detection target head is connected to a target head lateral movement mechanism, which is equipped with a pull rod displacement sensor. The pull rod displacement sensor is used to measure the lateral movement of the target head. The host computer control software is communicatively connected to the displacement sensor, the tilt sensor, the encoder, the lever-type displacement sensor, and the detection target head. It is used to determine the track type based on the tilt angle change law measured by the tilt sensor, and to select the corresponding measurement model for different track types to process the spot image, the track gauge, the tilt angle change, and the lateral movement of the target head to calculate the track smoothness and elevation smoothness.

2. The railway track smoothness horizontal curve measurement system according to claim 1, characterized in that, The main body of the track measuring trolley is a hollow crossbeam structure. The crossbeam is equipped with traveling wheels and auxiliary traveling wheels on both sides. The crossbeam has a connecting magnetic seat for connecting the push rod in the middle. The right side of the crossbeam is equipped with the displacement sensor and the transmission mechanism linked to the displacement sensor. The left side of the crossbeam is equipped with the tilt sensor. The upper left side of the crossbeam is equipped with a connecting seat for installing the detection target.

3. The railway track smoothness horizontal curve measurement system according to claim 2, characterized in that, The tilt sensor is an XY two-dimensional measurement type, which is horizontally installed directly below the detection target head, and the X-axis installation direction of the tilt sensor is consistent with the direction of the crossbeam.

4. The railway track smoothness horizontal curve measurement system according to claim 1, characterized in that, The light source device is equipped with a two-axis fine-tuning device, a horizontal bubble device, and an electronic display screen. The two-axis fine-tuning device is used to adjust the beam direction of the laser generator inside the light source device, and the electronic display screen is used to display the remaining power information of the light source device. Furthermore, the laser generator has a built-in spatial phase modulator.

5. The railway track smoothness horizontal curve measurement system according to claim 1, characterized in that, The detection target head includes a target head shell, a light shield, a filter, a CMOS camera and lens, and an embedded development board. The filter is a 650nm single-wavelength ultra-narrowband filter. The embedded development board is used to process the acquired light spot image and the data from each sensor and transmit them wirelessly to the host computer control software. The target head lateral movement mechanism is connected to the bottom of the detection target head. The rod-type displacement sensor is set in the target head lateral movement mechanism and is used to collect the lateral displacement of the detection target head relative to the crossbeam of the track measuring trolley in real time.

6. A method for measuring the smoothness of a railway track curve using the system described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1, System Calibration: Fix the light source device to one end of the track to be tested, place the track measuring trolley at the other end of the track to be tested, adjust the light source device so that the laser beam emitted by it is mapped onto the target surface area of ​​the detection target head, and record the light spot coordinates at this time as the reference coordinates; Step 2, Track type determination: Push the track measuring trolley to move along the track, and monitor the tilt angle changes of the track measuring trolley in the horizontal and vertical directions in real time through the tilt angle sensor. Determine the current track type as a straight line, upper curve, lower curve or horizontal curve based on the tilt angle change law; Step 3, Data Acquisition: During the movement of the track measuring trolley, the light spot image is continuously acquired by the detection target head and the light spot coordinates are extracted. The track gauge value is measured in real time by the displacement sensor, the tilt angle of the crossbeam is measured by the tilt sensor, the movement mileage is recorded by the encoder, and the lateral movement of the target head is measured by the rod-type displacement sensor. Step 4, Curvature measurement of curved track: For sections identified as curved tracks, the radius of curvature of the current track segment is calculated based on the mileage information recorded by the encoder and the cumulative angle change measured by the tilt sensor. Step 5, Smoothness parameter calculation and compensation: Based on the identified track type and the calculated radius of curvature, combined with the lateral movement of the target head, calculate the track smoothness parameter and the elevation smoothness parameter respectively, and compensate for the curvature error of the calculated results of the curved track.

7. The method for measuring the smoothness of railway track curves according to claim 6, characterized in that, The method for calculating the radius of curvature in step 4 is as follows: Let the distance the track measuring trolley travels within a unit mileage be L, and the cumulative change in horizontal angle measured by the tilt sensor be Δθ, then the horizontal radius of curvature R = L / Δθ; for upper or lower curve tracks, the vertical radius of curvature is calculated based on the cumulative change in vertical angle.

8. The method for measuring the smoothness of a railway track curve according to claim 6, characterized in that, Step 5, the calculation and compensation of ride comfort parameters, specifically includes: For a straight track, track smoothness High and low smoothness ,in( (x', y') are the reference coordinates, and (x', y') are the measured spot coordinates; For horizontal curved tracks, a curvature error compensation coefficient k_h = 1 + (d / 2R) is introduced, where d is the length of the track measuring trolley, R is the horizontal radius of curvature, and the compensated track smoothness is... High and low smoothness ; For tracks with upward or downward curves, a vertical curvature error compensation coefficient k_v = 1 + (d / 2R_v) is introduced, where R_v is the vertical curvature radius, and the compensated height and smoothness are... Track smoothness .

9. A method for measuring the smoothness of a railway track horizontal curve according to claim 6, characterized in that, It also includes a track level parameter calculation step: based on the current track gauge value W measured by the displacement sensor and the horizontal tilt angle of the crossbeam measured by the tilt sensor. Calculate the horizontal parameters of the track. .

10. A method for measuring the smoothness of a railway track curve according to claim 6, characterized in that, The extraction of the spot coordinates adopts a sub-pixel positioning algorithm, and the pixel offset is converted into the true offset through the pixel-to-true distance conversion relationship. The conversion relationship is: true offset = pixel offset × (filter size / number of pixels corresponding to the camera field of view) × target distance coefficient; and the lateral movement of the target head is used to correct the systematic deviation in the spot coordinates.

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