Doppler effect based deflection measurement system and method using multiple reference sensors

Abstract

A system and method for measuring the deflection of a loaded surface. The optical system includes multiple sensor heads for measuring Doppler frequency shift, each sensor head configured to emit a laser beam toward the surface, and a detector arranged to detect light reflected from the surface. A mounting beam secures the multiple sensor heads relative to each other along the beam. Two or more of the sensor heads are reference sensors, arranged together as a reference cluster, while at least one sensor head is a deflection sensor arranged away from the reference cluster and located in a region of high deflection on the surface. Based on the detection of emitted and reflected light from the coherent laser beam, the Doppler frequency can be determined and used to further determine the axial movement of the surface. The multiple reference sensors in the reference cluster provide reference signals for normalizing the deflection sensor data and reducing noise in the output.

Description

Technical Field

[0001] This invention relates to the field of surface-mounted deflection measurement and deflection, and more particularly to non-contact deflection measurement based on Doppler frequency shift measurement. Background Technology

[0002] This invention relates to the field of non-contact deflection measurement and represents a key technology for measuring surface deflection. Specifically, it addresses the challenges in deflection measurement systems that utilize the Doppler effect to detect surface deviations.

[0003] Deflection measurement, as a practice, helps to measure the properties of various surfaces, such as roads, conveyor belts, and similar structures. Key properties such as load-bearing capacity, durability, wear, and material integrity are often determined by measuring the deflection of these surfaces under a predetermined load. For this purpose, conventional methods employ various techniques, one common approach being the detection of Doppler shift in coherent light reflected from a surface moving relative to the detection system.

[0004] Doppler-based deflection measurement offers significant advantages, primarily its non-contact nature. This is particularly beneficial because it does not require direct physical interaction with the surface being measured. Therefore, it allows for continuous operation of the systems involved, such as uninterrupted traffic on a road or continuous activity on a conveyor belt, while measurements are being taken.

[0005] However, these methods have inherent limitations. The high sensitivity to minute changes in distance between the sensor and the surface leads to interference from external contaminants such as speckle decoupling on optically rough surfaces and dirt, resulting in accuracy issues. In particular, speckle decorrelation causes fluctuations in the Doppler signal, leading to misleading readings. Although solutions such as receiver diversification have been proposed to maintain a constant distance from the measurement surface, these solutions are technically complex and expensive.

[0006] Measurement noise introduces uncertainty into the determined deflection, and when multiple sensors are applied to measure along the deflection basin, any small error at each point accumulates in the final signal. This is typically handled by a reference sensor, but if the reference sensor is inaccurate or insufficiently located outside the deflection basin, the results will be unreliable. The calculated slope for each measurement sensor head contains additive white Gaussian noise from both the slope measurement sensor and the reference sensor. Noise can be reduced by averaging the readings from multiple sensors for the same target at each measurement point, but this is expensive. It is usually necessary to integrate the deflection velocity over time or distance to obtain the deflection depth. Since all calculated deflection velocities include correlated noise from the reference source, the noise from the reference sensor increases with the length of the deflection basin, regardless of the number of measurement locations along the basin.

[0007] Given these challenges, there is a need for a more efficient and economical non-contact deflection measurement solution that provides an improved signal that is less affected by small changes in surface roughness. Summary of the Invention

[0008] According to a first aspect of the invention, numerous objects and advantages, as can be seen from the description of the invention, are obtained through the following:

[0009] An optical system for measuring the deflection of a load-bearing surface, the optical system comprising:

[0010] Multiple sensor heads are used to measure Doppler frequency shift. Each of the multiple sensor heads is configured to emit a laser and includes a detector, arranged such that the laser can be emitted toward a surface, and the detector can collect light reflected from the surface.

[0011] A mounting beam is provided for fixing the plurality of sensor heads relative to each other, the sensor heads being arranged along the mounting beam.

[0012] Two or more of the sensor heads are reference sensors, and the reference sensors are arranged as a reference cluster.

[0013] At least one of the sensor heads is a deflection sensor, which is arranged away from the reference cluster.

[0014] The sensor head is arranged to measure the axial deflection of the surface, where the axial direction is understood to be the direction intersecting the surface whose deflection is to be measured. Deflection is understood as, for example, the deflection due to an applied force or the dynamic change in distance between the detector and the surface due to vibration. In other words, the deflection of a surface refers to the distance the surface moves relative to the surface when no force is applied, when a force is applied. Coherent light emitted by the sensor head will be emitted axially.

[0015] Laser emission can be achieved in various ways. Each sensor head may include a laser source, or lasers may be generated centrally for one or more sensor heads, and the laser may be directed to the sensor head, for example, via an optical fiber. In the following text, the term laser source will be used to refer to the origin of the laser from the sensor head, regardless of where the light is generated. For example, in the context of a sensor head, laser source may also refer to the emission point from a waveguide, such as an optical fiber contained within the sensor head.

[0016] Preferably, all deflection sensors are arranged such that the laser source emits coherent laser light along the same axis, i.e., the emitted laser beams are substantially parallel. In some variations, the optical system may be arranged such that the axis is substantially perpendicular to the surface, for example, perpendicular to 0-10 degrees, typically 0-2 degrees. In some variations, the optical system may be arranged such that the angle of the axis relative to the surface is 30 to 150 degrees. In some variations, the angle between the optical system and the surface may vary during the measurement period. For example, if the measurement is of a change in the detected speed due to surface deflection, the load causing the surface deflection may also cause a change in angle. The angle may also change due to relative movement between the optical system and the surface, as surface inhomogeneities can cause changes in angle depending on the relative positions during measurement.

[0017] Preferably, at least one of the reference sensors is arranged to emit coherent laser light in an axial direction, the axial direction being parallel to the emission axis of the one or more deflection sensors of the optical system.

[0018] The sensor heads are arranged on the mounting beam such that all sensor heads can simultaneously emit light onto the surface. Preferably, all sensor heads are arranged on the same side of the mounting beam.

[0019] Based on the measured velocity and the known route or distance, the optical system has traveled laterally. The measured velocity can be correlated with the position of the surface, for example, to determine the location of a weakened or damaged area in a support beneath the measured surface.

[0020] In this variant, the reference sensor and the deflection sensor are of the same type, i.e., they have the same performance characteristics and configuration except for their placement along the mounting beam. During use, the one or more deflection sensors are arranged to measure the deflection of the surface, preferably closer than the reference sensor to the load causing the surface deflection, which is arranged to measure the surface's no or minimal deflection. A further difference between the deflection sensor and the reference sensor lies in how the data acquired from those sensors is used to process the determined deflection.

[0021] The advantage of arranging all the sensor heads of the optical system on the mounting beam is that the sensor heads will move collectively in the same direction. In particular, arranging the two or more reference sensors as a reference cluster minimizes the relative variations between the reference sensors, for example, due to pitch or yaw.

[0022] A cluster of reference sensors allows for the understanding of a group of reference sensors arranged together, thereby minimizing the influence of the spatially different positions of each reference sensor in the cluster. Preferably, the reference sensors in the cluster are closer together than any deflection sensor in the optical system. Preferably, the distance between each adjacent reference sensor in the cluster is less than the distance between each adjacent deflection sensor, and less than the distance between the cluster and the nearest deflection sensor. This arrangement of the reference sensors in the cluster ensures that the reference sensors will collect data from the same area away from the deflection region, where the deflection sensor preferably measures deflection.

[0023] Due to their close spacing, all reference sensors in the reference cluster can be positioned outside the deflection region during operation of the optical system, so that all configured reference sensors of the optical system will be used only as reference sensors.

[0024] In a preferred variant, the distance between each adjacent reference sensor in the reference cluster is the same.

[0025] As a variant, a first reference cluster may be arranged at a first end of the mounting beam, while a second reference cluster may be arranged at a second end of the mounting beam, such that the correlation between measurements acquired by the first and second reference clusters can reveal the rotation of the mounting beam.

[0026] Measuring the axial (i.e., along the axis of the emitted laser beam) reflected beam causes interference between the emitted coherent laser beam and the Doppler-shifted reflected beam. The interference pattern can be measured by the detector, and the relative velocity between the optical system and the surface can be determined from the measurement. It should be understood that while the measurement measures reflection from the surface, it involves properties of the underlying structure, such as material integrity and how much material, rather than the surface structure, can yield under applied bending forces.

[0027] Preferably, with the simplification of measurement, the reflection is measured coaxially, i.e., the coherent laser beam and the reflected beam are coaxial. However, it should be understood that in other variations, the system can be used to measure the reflected beam, which is not coaxial with the emitted coherent laser beam, for example, by causing the reflected beam to be acquired at an angle or guided to the detector via a separate path.

[0028] The plurality of sensor heads includes two or more reference sensors and at least one deflection sensor. Preferably, the plurality of sensor heads includes a plurality of deflection sensors. The deflection sensors are arranged to detect the deflection of the surface by determining the Doppler frequency shift as described above. The reference sensors are used to acquire reference data for processing the data acquired by the deflection sensors.

[0029] Depending on the relative arrangement of two or more reference sensors, various types of reference data can be acquired. At least one of the two or more reference sensors arranged as a reference cluster can be positioned to detect along an axis parallel to the detection axis of the deflection sensor of the optical system. With such an arrangement, the sensor data from the reference sensors can be used to normalize the data detected by the deflection sensor. Having such reference sensors is crucial for compensating for the movement of the optical system itself relative to the surface. The reference sensors are arranged outside or at least away from the deflection basin, minimizing the influence of the deflection basin. Therefore, the reference data acquired by the reference sensors can be used to determine the deflection of the loaded surface relative to its unloaded state. By correlating the sensor data from the reference sensors and the deflection sensor with the surface position based on the understanding of the movement velocity of the optical system relative to the surface, it is possible to process deflection sensor data and reference sensor data at the same location.

[0030] Since the optical system of the present invention preferably includes multiple deflection sensors, and typically more deflection sensors than reference sensors, data from the same reference sensor is used to process the data acquired by each deflection sensor. Therefore, the noise and uncertainty of the reference signal data are multiplied, as this affects each reference sensor point. Thus, positioning multiple reference sensors together as a reference cluster is an effective and economical way to minimize the adverse effects of noise and / or errors in the reference sensor data, and consequently, the resulting analytical deflection data. The reference sensor data can be improved by arranging multiple reference sensors in parallel at closely spaced locations within a reference region (i.e., away from the deflection basin) to collect reference data, and by averaging the reference sensor data.

[0031] The optical system may further include a processing unit for online processing of the acquired sensor data, such as averaging reference sensor data, determining the translational velocity of the optical system relative to the surface, and / or correlating the deflection sensor data with the reference sensor data.

[0032] The optical system may also include a transmission unit for transmitting raw data for processing and / or transmitting processed data to an external processing unit for further analysis and use.

[0033] In some variations of the invention, the optical system includes more than one reference cluster, such as a first reference cluster and a second reference cluster.

[0034] According to another embodiment of the first aspect of the invention, each reference sensor in the reference cluster is arranged closer to a neighboring reference sensor than the nearest deflection sensor.

[0035] By spacing the reference sensors more closely apart than the deflection sensors, it becomes easier to obtain similar reference data from the reference sensors when all reference sensors are positioned in a reference region outside the deflection region. The benefits of multiple reference datasets are maximized by arranging all reference sensors outside the deflection region, as noise reduction is increased through enhanced understanding of the reference level and reduced noise impact.

[0036] According to another embodiment of the first aspect of the invention, each of the reference sensors is arranged within 100 mm of an adjacent reference sensor, for example within 75 mm of an adjacent reference sensor, more preferably within 50 mm of an adjacent reference sensor.

[0037] The close spacing of the reference sensors in a reference cluster offers several advantages. When using multiple reference sensors to average reference data, ideally, each sensor should detect the same point on the surface or points as close as possible to minimize surface variations. However, small variations in position can be beneficial, as they can determine whether a reference sensor is outside the deflection basin or whether it detects a consistent velocity; for example, sensors closer to the basin may detect higher velocities than those further from the contact point, indicating that they are not all entirely outside the deflection area. The close spacing of the reference sensors in the reference cluster further minimizes the effects of rotation on the mounting beam, such as pitch or yaw when the beam moves upward after a road bend, as the effects of this rotation increase with the distance between measurement points.

[0038] It should be understood that close spacing relates to two or more reference sensors arranged as a single reference cluster. Some variations of the optical system may include multiple reference clusters, such as a first reference cluster and a second reference cluster. The plurality of sensors in the first reference cluster are closely spaced, the reference sensors in the second reference cluster are also closely spaced, and the spacing between the first and second reference clusters may be larger, for example, located on opposite sides of one or more deflection sensors.

[0039] Having a first reference cluster and a second reference cluster spaced along the mounting beam allows for comparison of reference data, which can be used to determine various characteristics such as pitch and yaw as described above, as well as to provide information on the degree of deflection basin in the opposite direction to the longitudinal direction of the mounting beam.

[0040] According to another embodiment of the first aspect of the invention, two or more reference sensors are arranged adjacent to each other.

[0041] By arranging the reference sensors close to adjacent reference sensors, it is understood that, considering the physical limitations of installation due to the size of the sensor heads, the arrangement is such that adjacent sensors are spaced as close as possible. In other words, the spacing between the reference sensors in a reference cluster can be limited only by their physical dimensions. It should be understood that a first reference sensor can be arranged close to multiple adjacent reference sensors arranged along the longitudinal direction of the mounting beam on either side of the first reference sensor.

[0042] According to another embodiment of the first aspect of the invention, two of the reference sensors are arranged to emit substantially parallel laser beams.

[0043] As previously mentioned, reference sensor data acquired by individual reference sensors can be averaged to reduce noise in the reference sensor data. Arranging the reference sensors to emit parallel beams ensures that the acquired reference sensor data have similar characteristics, thereby minimizing the necessary processing for averaging the signals. In particular, ideally, two or more reference sensors arranged closely spaced and emitting parallel laser beams will acquire similar data from their measurements of the surface under similar conditions and at similar locations, allowing the acquired reference sensor data to be directly averaged for use in processing deflection data when determining the magnitude of the surface deflection.

[0044] The sensor axis is understood as the axis along which the sensor head emits the laser beam.

[0045] According to yet another variation of the first aspect of the invention, the reference cluster includes at least three reference sensors.

[0046] Preferably, the length of the mounting beam is at least three meters.

[0047] In a preferred variant, the first reference cluster is arranged at least one meter from the center of the mounting beam, for example, at least 1.25 meters from the center of the mounting beam.

[0048] In a preferred variant, the first reference cluster is arranged within one meter of the first end of the mounting beam, for example, within 30 centimeters of the first end of the mounting beam.

[0049] It should be understood that, preferably, the entire reference cluster can be arranged within one meter of the first end of the mounting beam, for example, within 30 centimeters of the first end of the mounting beam.

[0050] According to yet another variation of the first aspect of the invention, the reference sensors of the reference cluster are arranged as reference cells.

[0051] A reference unit can be understood as a component comprising the mechanical connections of multiple reference sensors. The reference unit may include a reference unit housing to which reference sensors of a reference cluster can be mounted. The reference unit may include one or more mounting rods for connecting the reference sensors of the reference cluster to each other, such that their relative distances can be determined by the mounting rods, and that the reference units can be collectively mounted on the mounting beam of the optical system.

[0052] Another object of the present invention is to provide a detection device for measuring the deflection of a load-bearing surface, the detection device comprising an optical system according to a first aspect of the invention, and a main vehicle for carrying the optical system and applying a load to the surface. The optical system is mounted to the main vehicle via a mounting beam. The mounting beam extends longitudinally along the direction of travel of the main vehicle. The mounting beam is arranged such that at least one sensor head is located in the deflection region.

[0053] The host vehicle can be any vehicle that carries the optical system along the surface to be inspected and applies a load to the surface. The host vehicle can be a self-propelled vehicle, such as a truck, or a unit that can be attached to and towed by other vehicles, such as a trailer towed by a car, truck, or train.

[0054] The mounting beam can be mounted to the main vehicle in any manner known in the art; for example, the mounting beam can be screwed or welded to the main vehicle, or it can be releasably mounted using a specific mounting bracket.

[0055] The mounting beam is arranged to extend longitudinally along the direction of travel of the host vehicle. In other words, a mounting beam arranged to extend longitudinally along the direction of travel of the host vehicle may mean that the mounting beam will be parallel to the diameter of the host vehicle's wheels. Preferably, the mounting beam is parallel to the diameter of the host vehicle's wheels, which are the contact points where a predetermined deflection load is applied to the surface to be measured. The rigidity and length of the mounting beam may cause one or more of the plurality of sensors to never follow the trajectory of the host vehicle, but the mounting beam will follow the direction of movement of the host vehicle.

[0056] The longitudinal arrangement of the mounting beam supporting multiple sensor heads has several advantages. Preferably, the reference cluster is arranged such that the two or more reference sensors detect the surface at the reference area, i.e., outside the reference basin, i.e., when the surface is not affected by load. Since the effect of surface load decreases with distance from the load, preferably, the reference cluster is spaced apart from the load, for example, from the wheels of the host vehicle that contact the surface. For example, by arranging the reference cluster between the axles of the wheel pair and / or extending the reference cluster behind the host vehicle, where the reference cluster does not enter the deflection basin of another load point (e.g., another wheel), the longitudinal direction of the vehicle provides the necessary spacing.

[0057] Furthermore, arranging mounting beams along the direction of travel of the main vehicle allows for monitoring of surface discontinuities along this direction, where many surfaces will experience significant wear due to the continuous load from vehicles traveling along them. Measurements collected along the direction of travel can be integrated from various measurement points to identify the area with the maximum deflection depth in that direction. This is the most suitable orientation for road and / or track monitoring. Additionally, if a more complete picture is needed, such as all lanes of a multi-lane highway, a complete picture can be obtained by providing multiple channels, allowing the main vehicle to travel along each lane to determine if defects are also extending laterally.

[0058] A deflection region can be understood as a portion of the surface that is deflected due to the load applied to it by the host vehicle. The deflection region can also be referred to as a deflection basin. In a preferred variant, a deflection sensor can be arranged near the load of the host vehicle, such that the sensor can be used to detect deflection at the desired center of the deflection basin. As described above, it is preferred that the optical system has multiple deflection sensors, such that the deflection sensors can be arranged along the deflection region to allow for mapping of the deflection region.

[0059] The deflection device may include a single optical system. The deflection system may include two or more optical systems. Preferably, the deflection device includes two optical systems arranged on either side of the main vehicle, enabling the measurement of surface deflection caused by the contact between the right and left wheels.

[0060] According to yet another variation of the second aspect of the invention, the first reference cluster is located in the first reference region.

[0061] According to another embodiment of the second aspect of the invention, the first reference cluster is arranged to continuously perform measurements in a reference region outside the deflection region.

[0062] According to another embodiment of the second aspect of the present invention, the first reference cluster is located in a first reference region, the center of which is located at the midpoint between the two points of maximum deflection caused by the main vehicle.

[0063] The reference region is understood to be a region far from the deflection region, i.e., a region nominally unaffected by the load applied to the surface by the host vehicle. It should be understood that while the reference cluster is located within the reference region, this may not be the case in every instance of operation. For example, the surface may have particularly damaged sections, which will result in deflection and an increased deflection region, thereby extending the area intended to be the reference region. In systems known in the art, such deflection of the desired reference region can lead to deflection measurements when the reference measurement is affected. An advantage of the present invention is that the multiple reference sensors of the reference cluster can be arranged to display changes when an unexpected change in the reference region occurs, for example, if the deviation between two reference datasets from two reference sensors increases.

[0064] In a preferred operation of the detection device, the reference sensors of the reference cluster measure only in the reference region. In other words, in a preferred operation of the detection device, the reference sensors do not measure in the deflection region. Preferably, the reference sensors do not move or measure in the deflection region. In a more preferred variant, all reference sensors are used only for reference measurements.

[0065] For a vehicle with multiple sets of wheels (e.g., a truck), a deflection basin extends around the wheel, contacts the surface at the wheel, and applies load to the surface in a manner that causes maximum deflection to occur after the point of contact relative to the direction of travel. The risk of the reference area being deflected is reduced by positioning the reference area at a midpoint between two points of maximum deflection, for example, between two different sets of wheels, thus separating the reference area as far as possible from the load point. The point of maximum deflection is understood as the theoretically maximum deflection location based on the load point of the vehicle; that is, the point obtained through mathematical analysis is the maximum value of the theoretical deflection of an ideal surface supported by the load of the vehicle. Therefore, in a preferred variant, the reference area is arranged between two adjacent wheel axles, closer to the rear of the adjacent wheel axles relative to the expected direction of travel of the vehicle.

[0066] In one variation, the width of the longitudinal deflection region of the mounting beam is one-third or less of the distance between two adjacent axes where the reference region is located, such as one-quarter or one-tenth of the width.

[0067] According to a variation of the second aspect of the invention, the center of the reference area is at least two meters away from each load point of the main vehicle, for example, at least three meters away. Preferably, this ensures that the center of the reference area is at least 2 meters away from the center of the deflection area, for example, at least 3 meters away. Such a distance increases the likelihood that the reference area will have a minimal impact on the deflection caused by the load of the main vehicle.

[0068] A third object of the present invention is to provide a method for optically measuring the deflection of a load-bearing surface, comprising:

[0069] - Provide an optical system comprising a plurality of sensor heads, each sensor head being used to emit a laser and including a detector, the plurality of sensor heads including one or more deflection sensors and two or more reference sensors arranged as a reference cluster;

[0070] - When the surface moves laterally relative to the emitted laser beam, a laser beam of coherent light from the sensor head of the optical system is emitted axially toward the surface;

[0071] - Measure the optical signal of the reflected light beam from the surface;

[0072] - Determine the Doppler frequency of the reflected beam;

[0073] - Based on the measurement data of the deflection sensor and the measurement data of two or more reference sensors in the reference cluster, the deflection of the surface in the axial direction is determined.

[0074] Since axial velocity is determined by the degree to which the material beneath the surface is affected by bending forces, the forces causing bending of the surface and underlying material, such as applied forces, must move relative to the surface in the lateral direction to allow any velocity in the axial direction to occur. Alternatively, axial velocity can be generated by standing waves or vibrations of the material. Axial velocity is necessary to determine the Doppler frequency, which in turn is used to determine the surface bending. For example, a bending device, i.e., a device for applying bending forces, can be mounted with an optical system such that the optical system and the bending force move together relative to the surface, causing the axial velocity to vary in response to a constant bending force as the material's structural strength bends to varying degrees.

[0075] In this system, reference data is acquired by two or more reference sensors in a reference cluster. This reference data is then used to process deflection sensor data to determine the deflection of the surface. For example, the reference sensor data can be used to normalize the deflection sensor data to determine the deflection relative to the surface when it is not under load. As another example, the reference sensor data can be used to determine the lateral velocity of the optical system's movement relative to the surface. As previously described, the reference cluster can simultaneously acquire multiple types of reference data and use them to determine the surface deflection.

[0076] In the case where the optical system is mounted on a vehicle passing through the surface being measured, the lateral movement direction of the surface relative to the emitted laser beam can also be considered as the direction of travel.

[0077] In a preferred variant, all sensor heads of the optical system simultaneously emit laser beams toward the surface.

[0078] In a preferred variant, the optical system includes multiple deflection sensors. In this configuration, each deflection dataset acquired by the deflection sensors is post-processed using reference sensor data acquired by two or more reference sensors from a reference cluster. Therefore, multiple deflection sensors are able to simultaneously determine the surface deflection at various points along the surface.

[0079] The processing of the acquired sensor data can be performed in multiple steps. For example, reference sensor data can be analyzed separately to determine, for instance, a reference velocity for the surface and / or velocity relative to the lateral direction of travel. Subsequently, the analyzed reference sensor data can be used when analyzing the data acquired by each deflection sensor of the optical system.

[0080] According to another embodiment of the third aspect of the invention, when determining the deflection of the surface in the axial direction, data collected by two or more reference sensors of the reference cluster are used to normalize the data collected by one or more deflection sensors.

[0081] It is known in the art to normalize data acquired by deflection sensors using a single reference sensor. Using data from multiple reference sensors offers some of the aforementioned advantages. In particular, noise is reduced by averaging the reference data across multiple reference sensors, thereby reducing the effects of local variations and noise from each sensor head.

[0082] Normalization of deflection sensor data can be performed in any order or manner known in the art. The Doppler frequency shift can be determined for both the reference sensor and the deflection sensor, thereby determining the deflection. The reference velocity of the reference sensor and the deflection velocity of the deflection sensor can be determined separately, and then normalization can be performed.

[0083] According to an embodiment of the third aspect of the present invention, the acquisition of reference sensor data and the acquisition of deflection sensor data are performed simultaneously.

[0084] By simultaneously acquiring reference sensor data and deflection sensor data, continuous measurements can be performed, eliminating the need to pause deflection sensor measurements to provide a reference level, thus making the process more efficient. Furthermore, the simultaneous acquisition of reference sensor data while the operating system is acquiring deflection data allows for adjustments to the reference level; that is, it takes into account potential variations in the support surface, such as those due to surface tilt or material changes, regardless of the integrity of the support material being investigated.

[0085] According to a variation of the third aspect of the invention, reference sensor data acquired by at least the first and second reference sensors of the reference cluster are compared to verify the normal operation of the optical system.

[0086] Two or more reference sensors in a reference cluster are arranged closely spaced such that they will detect surface regions expected to have similar characteristics, e.g., at similar distances from the reference sensors, resulting in similar Doppler frequency shifts detected by the reference sensors. Therefore, each reference sensor in a sensor cluster arranged in a similar manner (e.g., with parallel sensor axes) is expected to acquire a similar dataset. Thus, an increase in the difference between the first and second reference sensor datasets indicates a change in system state. This change can indicate various problems, such as an error in one of the reference sensors causing a malfunction in its output, for example, increased noise, the presence of dirt or debris on the surface causing changes unrelated to the surface itself, or surface damage so severe that it increases the deflection basin, affecting some reference sensors and causing them to be outside the reference region.

[0087] In a preferred variant, reference sensor data from all similarly configured reference sensors are compared to determine whether only a single sensor is affected, for example, due to a sensor malfunction. For these variants, the method may include determining whether signals from one or more reference sensors should be excluded from the reference sensor data used to process the acquired deflection sensor data. For example, if a reference dataset acquired by a single reference sensor exceeds a variation threshold, while reference datasets provided by other reference sensors in the reference cluster are within acceptable ranges, data processing may be based solely on reference datasets falling within the acceptable range, while divergent reference datasets exceeding the acceptable reference range may be excluded from processing.

[0088] For this variant, if the difference between the reference sensor data collected by the first reference sensor and the second reference sensor of the comparison indicator reference cluster exceeds a predetermined threshold, the system can indicate an error state.

[0089] According to an embodiment of the third aspect of the present invention, each reference sensor is used only for reference measurements.

[0090] In other words, during the intended operation, each reference sensor will acquire reference sensor data only from the reference area, and the acquired reference sensor data will only be used for post-processing, determining the reference level, and / or normalizing the data acquired from the deflection sensor. The reference sensor will not be used intermittently as a deflection sensor and is by no means used to measure reflections from the deflection area. Attached Figure Description

[0091] The following are examples illustrating embodiments of the present invention:

[0092] Figure 1An optical system for detecting surface deflection is shown, the optical system having multiple reference sensors arranged parallel to the sensor axis.

[0093] Figure 2 An optical system for detecting surface deflection is shown, the optical system having multiple reference sensors.

[0094] Figure 3 An embodiment of a detection device is shown, wherein the optical system is mounted on a truck.

[0095] Figure 4 A top view of a portion of the detection device at the tire level is shown, in which the optical system is arranged relative to the wheel pair, which is the contact point that applies a load to the surface.

[0096] Figure 5 A flowchart of a method for optically measuring the deflection of a load-bearing surface is shown. Detailed Implementation

[0097] The invention will now be explained in more detail with reference to the accompanying drawings.

[0098] However, the invention may be embodied in forms other than those described below, and should not be construed as limited to any of the examples set forth herein. Rather, any examples are provided so that the disclosure of the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals refer to the same elements throughout. Therefore, similar elements will not be described in detail in conjunction with the description of each figure. Detailed descriptions of embodiments of an optical system for measuring surface deflection, a detection device integrating the optical system, and a method for determining surface deflection using the optical system are provided.

[0099] Figure 1 An embodiment of an optical system 10 according to the present invention is shown. The optical system 10 includes a mounting beam 40 along which sensor heads 12 are arranged. Each sensor head includes a laser source that emits a coherent laser beam 22 and a detector for detecting a reflected beam 32 reflected from a surface 1, the deflection of which is determined.

[0100] Multiple sensor heads 12 include multiple deflection sensors 20. The multiple deflection sensors 20 are spaced apart along the mounting beam 40, with their axes parallel, such that coherent laser beams 22 emitted from a reference sensor 50 toward surface 1 are emitted parallel to each other. The deflection sensors 20 are arranged such that at least one of the deflection sensors 20 emits the coherent laser beam 22 onto a deflection region 2 of surface 1, where the surface is deflected due to an applied load. The applied load is indicated by the arrow F causing the deflection of surface 1. The width of the deflection region 2, also known as the deflection basin, will depend on the amplitude of the applied load F and the type and integrity of the support beneath surface 1. Part of the basic principle of the method is that the amplitude and deflection, as well as the shape of the deflection basin, can be used to determine the structural integrity of the material supporting surface 1, thus having the potential to reveal defects in the foundation and / or weaker areas. Therefore, it is not guaranteed that each deflection sensor 20 will be arranged to detect the deflection of the deflection region 2 in all use cases. In a preferred embodiment, a plurality of deflection sensors 20 are distributed along a portion of the mounting beam 40, with a high density around the theoretical point of maximum deflection and a lower density further away from the point of maximum deflection, i.e., further spaced out. Preferably, the section of the mounting beam 40 in which the deflection sensors 20 are arranged, regardless of whether its distribution is uniform, covers at least half the length of the mounting beam 40.

[0101] Figure 1 The plurality of sensor heads 12 shown also include a subgroup of two reference sensors 50 arranged as a reference cluster 55. The two reference sensors 50 of the reference cluster 55 are arranged with parallel sensor axes such that coherent laser beams 22 emitted from the reference sensors 50 toward the surface 1 are emitted parallel to each other. The reference cluster 55 is arranged to emit the coherent laser beams 22 onto a reference region 5 of the surface 1, where the surface is not warped by the applied load. With this arrangement, the Doppler frequency shift detected by the reference sensors 50 of the reference cluster 55 provides a reference velocity corresponding to the absence of surface warping. This reference velocity can be used to normalize the data acquired by the warping sensor 20, thereby normalizing the warping caused by the load. Therefore, the reference velocity ensures that the detected velocity change is due to a load-induced offset, rather than, for example, a change in the pitch of the surface 1 or other changes unrelated to the load.

[0102] It should be understood that when the reference cluster 55 is arranged to detect the reference area 2, since there is no surface deflection under the applied load, the size of the deflection basin in the longitudinal direction of the mounting beam 40 depends on the support under the surface 1 as the optical system 10 translates along the surface 1 in the longitudinal direction of the mounting beam 40, and can vary along the surface 1 during deflection measurement. Therefore, the reference cluster 55 is used to measure the non-deflected reference area 5 of the surface; however, sometimes the deflection basin can extend into the reference area 5. Thus, the reference area can also be defined as being at a specific distance from the contact point where the load is applied, and / or the placement of the reference cluster 55 can be relative to the mounting beam 40 or the main vehicle (see [reference]). Figure 3 The reference cluster 55 is determined, rather than based on reference region 5. In a preferred embodiment of the invention, the reference cluster 55 is positioned closer to the first end of the mounting beam 41 than any of the deflection sensors 12 of the optical system 10, the first end of the mounting beam 41 being at the foremost position relative to the direction of travel v. Since the deflection basin will typically move toward the opposite end of the mounting beam 40, it is advantageous to place the reference cluster 55 near the first end 41, where the first end of the beam 41 is at the foremost position and least likely to be close to the deflection section of the surface.

[0103] The reference sensors 50 of the reference cluster 55 are arranged such that their sensor axes are parallel to each other and parallel to the sensor axis of the deflection sensor 20 of the optical system.

[0104] In a preferred embodiment of the invention, the sensor heads 12 are identical, so that the deflection sensor 20 and the reference sensor 50 are identical, and their outputs can be directly correlated.

[0105] During use, the optical system 10 must translate relative to the surface 1 in a direction laterally to the direction of emission of the coherent laser beam from the sensor head 12. This lateral translation is indicated by the arrow v.

[0106] The two reference sensors 50 of the reference cluster 55 are arranged close to each other, such that they are in contact, and the distance between the emitted coherent laser beams 22 is limited by the physical dimensions of the sensor head 12, such that the coherent laser beams 22 are emitted in a parallel manner and are spaced as closely as possible. In other embodiments, the reference sensors 50 may be further spaced apart due to constraints other than the physical dimensions of the sensor head 12, such as heating caused by the sensor head 12.

[0107] Although Figure 1 The embodiment shown illustrates a reference sensor cluster 55 having two reference sensors 50, but other embodiments within the scope of the invention may include additional reference sensors 50. Similarly, the number of deflection sensors 20 may vary between embodiments of the invention.

[0108] As shown in the figure, the sensor head 12 is mounted on the side of the mounting beam facing the surface 1 whose deflection is to be detected. In other embodiments, the sensor head 12 can be arranged on the other side of the mounting beam 40, as long as they can be arranged to emit a coherent laser beam 22 onto the surface 1. All sensor heads 12 can be arranged on the same side of the mounting beam, such as... Figure 1 As shown. In other embodiments, the sensor head 12 may be arranged on different sides of the mounting beam 40.

[0109] Figure 2 An embodiment of the optical system 10 according to the present invention is shown, which includes a reference cluster 55 having three reference sensors 51, 52, and 53. The reference sensors of the reference cluster 55 are arranged close together along the longitudinal direction of the mounting beam 40.

[0110] A reference cluster 55, comprising three reference sensors 51, 52, and 53, is arranged at the first end 41 of the mounting beam 40. Another reference cluster, including two reference sensors 50, is arranged at the second end 42 of the mounting beam 40. In other embodiments, the reference clusters 55 at the first end 41 and the second end 42 of the mounting beam 40 may be identical.

[0111] Both the first reference sensor 51 and the second reference sensor 52 emit coherent laser beams 22 toward the surface 1, and then the reflected light beams 32 are reflected from the surface 1 back to the detectors of the sensor heads of the first reference sensor 51 and the second reference sensor 52.

[0112] The reference sensor data acquired from the first reference sensor 51 can also be used for noise reduction in the direction perpendicular to the translation direction v.

[0113] The first reference cluster 55 also includes a third reference sensor 53. The second reference sensor 52 and the third reference sensor 53 are arranged such that their sensor axes are parallel, i.e., the coherent laser beams 22 emitted from the second reference sensor 52 and the third reference sensor 53 are parallel. Preferably, the second reference sensor 52 and the third reference sensor 53 can be arranged such that their sensor axes are perpendicular to the translation direction v. As previously mentioned, the advantage of arranging multiple reference sensors with parallel sensor axes is, for example, noise reduction and verification of the intended function of the sensors.

[0114] Three reference sensors 51, 52 and 53 of the reference cluster 55 at the first end 41 of the mounting beam are arranged in parallel to emit coherent laser beams 22 onto the surface.

[0115] A reference cluster 55 having more than two reference sensors 50 provides further improvement in the reference signal because it increases the determinism of any of the reference sensors 50 in the cluster 55, reduces noise, and improves robustness to error or fault behavior.

[0116] Other embodiments within the scope of this invention may include a reference cluster having more reference sensors, such as three or more reference sensors arranged parallel to the sensor axes, thereby further reducing noise.

[0117] Figure 2 The illustrated exemplary embodiment includes a first reference cluster 55 disposed at a first end of a mounting beam 41 and a second reference cluster 56 disposed at a second end of a mounting beam 42. In the illustrated embodiment, the second reference cluster 56 includes two reference sensors 50. The two reference sensors of the second reference cluster 56 are arranged parallel to each other, i.e., they are arranged to emit parallel coherent laser beams 22. The two reference sensors of the second reference cluster 56 are spaced apart such that they are not close together, but are still arranged in a deflected reference region away from the surface.

[0118] By means of a reference cluster arranged at the end of the mounting beam, it can be understood that the reference cluster is closer to the end of the mounting beam than any other sensor head among the multiple sensor heads of the optical system. If the reference cluster is arranged longitudinally from the end of the mounting beam within a quarter of the length of the mounting beam, more preferably within a fifth of the length of the mounting beam, for example, within a tenth of the length of the mounting beam at the end of the mounting beam, then the reference cluster can be considered to be arranged at the end of the mounting beam.

[0119] It should be understood that many other variations and contellations of reference sensors within one or more reference clusters of an optical system are within the scope of this invention. An optical system may include a single reference cluster, two or more reference clusters. Each reference cluster of this invention may have any number of reference sensors, which may be arranged in various ways. A reference cluster may include two or more reference sensors arranged close together and one or more reference sensors spaced apart from other reference sensors. An optical system having two or more reference clusters may have... Figure 2 In the example, the reference sensors in the first and second reference clusters are different series, or the first and second reference clusters may be located at different positions along the optical system.

[0120] like Figure 2 As shown, the deflection sensors 20 of the optical system 10 can be distributed in a non-uniform manner along the beam 40, for example, with closer spacing where maximum deflection is expected to occur, while being further spaced at the desired edges of the deflection basin. In other embodiments, the deflection sensors 20 can be equidistant.

[0121] Figure 3This is a schematic diagram of an embodiment of a detection device 100 having a host vehicle 110, which has the form of a truck traveling along a surface 1 in the direction indicated by arrow v. The truck has a weight that causes it to apply a load to the surface 1 at the contact point of its wheels, which defines a load point 112. The load from the host vehicle 110 results in a deflection basin on the surface 1. The shape and extent of the deflection basin (also referred to as a deflection region) depend on the strength and structure of the area where the load vehicle is located, i.e., on the material beneath the surface 1 studied by the method of the present invention.

[0122] The detection device 100 includes an optical system 10 connected to the main vehicle 110 via a mounting beam 40. Various embodiments of the optical system may be used in the detection device, and it should be understood that... Figure 3 The illustration is a simplified illustration of a single embodiment.

[0123] The optical system may include a plurality of deflection sensors 20. Preferably, the optical system may be arranged such that the deflection sensors 20 are positioned at the load point 112, for example, at the truck wheel axle along the length of the truck, so that the deflection sensors 20 can detect the expected maximum deflection of surface 1. Preferably, the plurality of deflection sensors 20 are arranged along the mounting beam 40 on either side of the load point 112, thereby simultaneously mapping various points along the slope of the deflection region.

[0124] Preferably, the first reference cluster 55 of the optical system 10 can be arranged equidistantly from two mathematically determined maximum deflection points. Preferably, the first reference cluster 55 is arranged between adjacent wheel pairs such that the first reference cluster 55 is closer to the rearmost wheel pair than the foremost wheel pair, making the reference cluster 55 most likely to be arranged away from the deflection basin caused by the main vehicle. Preferably, the distance from the load point 112 to the first sensor cluster 55 in the translational direction v is at least 2 meters, more preferably about 3 meters. Depending on the size of the main vehicle 110 and the intensity of the ground beneath the surface 1 along which the detection device 100 moves, the deflection area can extend to the area from which light from one or more reference sensors of the optical system is reflected. In this suboptimal case, it is particularly advantageous to arrange multiple reference sensors close together as part of the first reference cluster 55, because by comparing reference sensor data from adjacent reference sensors of the same reference cluster 55, it is possible to confirm whether the detected area is a flat reference area or whether the area detected by the reference sensors is tilted due to deflection load.

[0125] For some embodiments of the detection device, such as Figure 3As shown, the optical system 10 may include a second reference cluster 56 disposed at the end of the mounting beam opposite to the end where the first reference cluster 55 is disposed. In some embodiments, as shown, the second end of the mounting beam 40 may extend beyond the length of the host vehicle, thereby allowing the second reference cluster 56 to be disposed further away from the deflection point 112, increasing the chance of the second reference cluster 56 emitting a coherent laser beam toward a reference area of ​​surface 1, where the load of the host vehicle 110 does not cause deflection of surface 1. Other embodiments may arrange the optical system such that the mounting beam does not extend beyond the length of the host vehicle in the direction of travel, minimizing obstruction by the host vehicle to the area of ​​surface 1 being investigated (e.g., a highway).

[0126] Some embodiments of a deflection device may include two or more reference clusters. Other embodiments of a deflection device may include a single reference cluster of multiple reference sensors.

[0127] Figure 3 Reference clusters 55 and 56 are shown as single units. In some embodiments, reference clusters 55 and 56 may be closely spaced collections of two or more reference sensors arranged in a manner similar to the arrangement of each deflection sensor 20 in the optical system 10. In other embodiments, reference clusters 55 and 56 may be single reference units fixed to the mounting beam 10, each including two or more reference sensors 50 fixed relative to each other, for example, connected by a connecting rod or mounted within a reference housing.

[0128] In some embodiments, the reference sensors of the reference cluster are arranged close to the longitudinal direction of the mounting beam 40. In other embodiments, the reference cluster may be arranged as a reference unit having two or more reference sensors arranged at the same longitudinal position along the mounting beam, such that the reference sensors of the reference cluster are arranged close to each other laterally relative to the mounting beam and the direction of travel, for example in a plane substantially parallel to the surface of the reference region.

[0129] Figure 4 The diagram illustrates possible arrangements of the optical system 10 relative to the wheels of the main vehicle along the longitudinal direction. Note that this diagram is not drawn to scale but rather provides an illustration of preferred relative arrangements. Similarly, the placement of the optical system 10 in the transverse direction to the travel direction v can differ. Figure 4 On the right side, the optical system 10 is shown positioned between the two pairs of tires in a dual-tire configuration, so that the deflection sensor of the optical system can be optimally aligned with the point of maximum deflection. This arrangement is preferred for dual-tire mainframe vehicles. Figure 4On the left side, an optical system 10 is shown arranged between the tires connected by axle 115. This arrangement can be considered an internal placement, wherein the optical system is arranged such that wheels on the same axle 114 are positioned on opposite sides of the optical system 10. This internal placement of the optical system 10 is preferred for mainframe vehicles without dual tires. This arrangement can also be used for vehicles with dual tires, for example, due to other limitations on mounting the optical system to the mainframe vehicle. In other embodiments, the optical system 10 may be arranged externally to the vehicle, i.e., such that all wheels on axle 114 are located on the same side of the optical system 10.

[0130] The illustrated main vehicle has at least two sets of wheels, each set including two wheels and an axle 115 connecting these wheels. In a preferred embodiment, the optical system 10 is arranged close to one of the wheels, which serves as the load point, and this arrangement of the optical system ensures that one or more of the deflection sensors 20 can detect the deflection area of ​​surface 1.

[0131] In a preferred variant, the optical system is arranged such that a reference cluster 55, comprising multiple reference sensors, is positioned near the rearmost axle 115 of the adjacent wheelset of the main vehicle. Preferably, the reference cluster 55 is positioned at the point where analysis has shown that the reference cluster 55 will be furthest from the two deflection basins caused by the contact point with the adjacent wheelset in the direction of travel. Thus, the reference cluster 55 is positioned at a point along the longitudinal axis of the mounting beam, at which surface 1 will experience minimal deflection due to the load of the main vehicle applied to each load point of the wheel.

[0132] This arrangement also allows the optical system 10 to be positioned such that the longitudinal direction of the mounting beam 40 is along the direction of travel indicated by arrow v. This arrangement is advantageous for many host vehicles, as it allows the reference cluster 55 to be as far away as possible from the two adjacent load points without extending the mounting beam of the optical system beyond the host vehicle along the longitudinal axis of the mounting beam 40. Furthermore, this arrangement of the optical system 10 relative to the host vehicle allows the reference cluster 55 to be rigidly mounted relative to the deflection sensor 20; that is, the optical system 10 can be an integrated system mounted as a single unit on the host vehicle. When the host vehicle is a vehicle that travels along surface 1, similar to other vehicles that need to use the surface (e.g., a truck traveling along a road or a train traveling along a set of tracks), arranging multiple deflection sensors 20 along the translational direction v is further advantageous, as this allows the structural integrity of surface 1 to be studied along the direction in which surface 1 will experience the greatest wear, thus providing a more realistic indication than a lateral image and potentially making it easier to identify local defects.

[0133] In a preferred variant of the main vehicle equipped with dual tires, the optical system 10 is mounted on the main vehicle in a manner arranged between the two tires of the dual tire pair, such that the maximum deflection of surface 1 relative to the load applied to the wheel can be detected while the sensor head of the optical system 10 can still emit coherent laser light toward surface 1 without the beam being interrupted by any part of the main vehicle (e.g., the wheel). In other embodiments, the optical system 10 can be mounted as close as possible to the surface of the wheel facing the axle 115, such that the optical system 10 is internally mounted, as... Figure 4 As shown on the left.

[0134] The detection device can have, for example Figure 4 The diagram shows multiple optical systems, for example, one optical system associated with each tire track. In a preferred embodiment, the detection device includes two optical systems, which are preferably mounted in the same manner as wheels connected to opposite ends of the axle. In other embodiments, the two or more optical systems of the detection device may be arranged differently.

[0135] Figure 5 A flowchart illustrating the steps of an embodiment of a method for optically measuring the deflection of a load-bearing surface according to the present invention is shown.

[0136] According to the present invention, providing an optical system 210 is necessary for data acquisition. The optical system may be part of a machine for measuring the surface of a moving surface (such as a conveyor belt). The optical system may be part of a detection device having an optical system carried by a host vehicle as described above. A load 211 is provided, which is fixed relative to the optical system, while both the load and the optical system are translated relative to the surface 1.

[0137] Multiple sensor heads emit coherent laser beams 220 toward the surface whose deflection is to be determined. In this step of the method, both deflection sensor emission 221 and reference sensor emission 222 occur.

[0138] Then, the detectors of multiple sensor heads detect reflected light 230 from the surface whose deflection is to be determined. In this step of the method, both deflection sensor detection 231 and reference sensor detection 232 occur.

[0139] Although the emission step of a coherent laser beam must be initiated before the reflected light originating from the laser beam can be detected, it should be understood that once emission and detection begin, they can be performed consecutively.

[0140] Once the detector in the sensor head has acquired the data, data processing step 250 can proceed. Data processing can be performed entirely or partially using the integrated processing unit, or it can be performed entirely or partially outside the optical system after being transmitted to an external processing unit.

[0141] Data processing 250 includes determining the Doppler frequency shift 251, which is then used to determine the deflection output 260 as an analysis output, and providing data related to surface deflection.

[0142] Data processing 250 may include multiple sub-analyses, including but not limited to averaging reference sensor output 252, normalization of sensor data 253, and / or determination of translation speed 254.

[0143] Reference List

[0144] 1. Measure its deflected surface

[0145] 2 Deflection Zone

[0146] 5 Reference Areas

[0147] 10 Optical Systems

[0148] 12 sensor heads

[0149] 20 deflection sensor

[0150] 22 coherent laser beams

[0151] 30 detectors

[0152] 32 reflected beam

[0153] 40 Installation Beam

[0154] 41 Install the first end of the beam

[0155] 50 reference sensors

[0156] 51 First Reference Sensor

[0157] 52 Second Reference Sensor

[0158] 53 Third Reference Sensor

[0159] 55 reference clusters

[0160] 100 detection device

[0161] 110 main vehicle

[0162] 112 load points

[0163] 115 axis

[0164] 210 provides optical systems

[0165] 211 load provision

[0166] 220 laser beam emission

[0167] 221 Deflection Sensor Launch

[0168] 222 Reference Sensor Launch

[0169] Detection of 230 reflected light

[0170] 231 Deflection Sensor Detection

[0171] 232 reference sensor detection

Claims

1. An optical system for measuring the deflection of a load-bearing surface, characterized in that, The optical system includes: Multiple sensor heads are used to measure Doppler frequency shift. Each of the multiple sensor heads is configured to emit a laser and includes a detector, arranged such that the laser can be emitted toward a surface, and the detector can collect light reflected from the surface. A mounting beam is provided for fixing the plurality of sensor heads relative to each other, the sensor heads being arranged along the mounting beam. Two or more of the sensor heads are reference sensors, which are arranged as a reference cluster. At least one of the sensor heads is a deflection sensor, which is arranged away from the reference cluster.

2. The optical system according to claim 1, characterized in that, Each of the reference sensors in the reference cluster is arranged to be closer to the nearest reference sensor than the nearest deflection sensor.

3. The optical system according to any one of the preceding claims, characterized in that, Each of the reference sensors is arranged within 50 mm of the adjacent reference sensor.

4. The optical system according to any one of the preceding claims, characterized in that, Two or more reference sensors are arranged in close proximity to each other.

5. The optical system according to any one of the preceding claims, characterized in that, Two of the reference sensors are arranged to emit substantially parallel laser beams.

6. The optical system according to any one of the preceding claims, characterized in that, The reference sensors of the reference cluster are arranged as reference units.

7. The optical system according to any one of the preceding claims, characterized in that, The reference cluster is arranged within one meter of the first end of the mounting beam, for example, within 30 centimeters of the first end of the mounting beam.

8. The optical system according to any one of the preceding claims, characterized in that, The optical system includes a first reference cluster and a second reference cluster.

9. A testing device for measuring the deflection of a load-bearing surface, characterized in that, The device includes: The optical system according to any one of claims 1-6, A main vehicle for carrying the optical system and applying a load to the surface, the optical system being mounted to the main vehicle via a mounting beam arranged to extend longitudinally along the direction of travel of the main vehicle. The mounting beam is arranged such that at least one deflection sensor will be located in the deflection region.

10. The detection device according to claim 9, characterized in that, The first reference cluster is located in the first reference region, and the first reference cluster is arranged to be continuously measured in the reference region outside the deflection region.

11. A method for optically measuring the deflection of a load-bearing surface, characterized in that, The method includes: An optical system is provided, the optical system comprising a plurality of sensor heads, each sensor head for emitting a laser and including a detector, the plurality of sensor heads including one or more deflection sensors and two or more reference sensors arranged as a reference cluster; When the surface moves laterally relative to the emitted laser beam, the laser beam of coherent light from the sensor head of the optical system is emitted axially toward the surface; Measure the optical signal of the reflected light beam from the surface; Determine the Doppler frequency of the reflected beam; Based on the measurement data from the deflection sensor and the measurement data from two or more reference sensors in the reference cluster, the deflection of the surface in the axial direction is determined.

12. The method according to claim 11, characterized in that, The acquisition of reference sensor data and deflection sensor data are performed simultaneously.

13. The method according to claims 11-12, characterized in that, When determining the deflection of the surface in the axial direction, data acquired by two or more reference sensors of the reference cluster are used to normalize the data acquired by one or more deflection sensors.

14. The method according to any one of claims 11-13, characterized in that, Each reference sensor is used only for reference measurements.

15. The method according to any one of claims 11-14, characterized in that, The reference sensor data acquired by at least the first and second reference sensors of the reference cluster are compared to verify the normal operation of the optical system.

Images