A high-precision real-time vehicle speed measurement device and method

Abstract

This invention discloses a high-precision real-time vehicle speed measurement device and method, relating to the field of road dynamic deflection detection technology. The device features a swingable wheel frame structure, with a semi-flexible tire mounted on the axle. A timing belt surrounds the outer circumference of the semi-flexible tire and rolls in contact with the road surface. An encoder contacts the timing belt and collects its motion information to obtain the vehicle's real-time speed. A tensioning pulley compensates for changes in the timing belt's tension caused by the semi-flexible tire's deformation under pressure, while a correction pulley limits lateral deviation of the timing belt. A constant-pressure valve, cylinder, and counterweight together form a pressure-maintaining structure, ensuring a relatively stable ground contact between the semi-flexible tire and the timing belt during vehicle movement. This invention reduces the impact of road surface undulations, wheel jumps, and changes in effective wheel diameter on speed measurement results, improving the stability and consistency of vehicle speed measurement during road dynamic deflection detection.

Description

Technical Field

[0001] This invention relates to the field of road dynamic deflection detection technology, specifically to a high-precision real-time vehicle speed measurement device and method. Background Technology

[0002] In recent years, with the continuous expansion of my country's highway transportation infrastructure, the importance of highway maintenance and road service performance evaluation has been increasing. During long-term service, roads are affected by factors such as traffic loads, environmental changes, material aging, and differences in construction quality, gradually developing structural or functional defects. Compared to reparative maintenance after defects occur, preventative maintenance is generally more effective in reducing the total life-cycle maintenance cost of roads. Therefore, road inspection technology, as a crucial front-end link in road maintenance decision-making, is receiving increasing attention from the industry, while also placing higher demands on the inspection efficiency, continuity, and data reliability of road non-destructive testing equipment.

[0003] Road deflection is a crucial indicator of road structural bearing capacity, playing a vital role in roadbed and pavement completion acceptance, road structural performance evaluation, and maintenance decisions. Traditional deflection testing devices typically employ point-based detection methods, resulting in a limited number of testing points and relatively low efficiency. Furthermore, conducting traditional deflection testing on highways or other roads may require traffic control or low-speed operations, posing certain safety risks and limiting operational efficiency. To improve testing efficiency, in recent years, domestic and international organizations have gradually developed and applied high-speed laser dynamic deflection testing equipment. This type of equipment can be installed on testing vehicles, continuously or nearly continuously acquiring road deflection data during vehicle movement, providing data support for identifying road structural defects and making preventative maintenance decisions.

[0004] In high-speed laser dynamic deflection detection, real-time vehicle speed is one of the crucial parameters for data processing. Real-time vehicle speed is typically used to determine the road mileage corresponding to the detection data and participates in sensor data synchronization, detection spacing control, dynamic response analysis, and subsequent deflection calculation. Some high-speed laser dynamic deflection detection equipment can perform detection within a speed range of approximately 20 km / h to 90 km / h. Under these dynamic detection conditions, deviations in real-time vehicle speed measurement may affect the matching of detection points and the deflection data processing results. Depending on the specific calculation model and equipment parameters, vehicle speed errors may also be amplified during deflection calculation. Therefore, improving the stability and consistency of real-time vehicle speed measurement is of practical significance for ensuring the accuracy of dynamic deflection detection results.

[0005] Existing road inspection vehicles can obtain vehicle speed using methods such as vehicle speed signals, satellite positioning speed measurement, radar speed measurement, or external speed measuring wheels. Among these, external speed measuring wheels have some applications in road inspection equipment due to their relatively simple structure, convenient installation, and direct response. External speed measuring wheels typically contact the road surface through tires or rollers, and use encoders to collect the rotation information of the speed measuring wheel, then calculate the vehicle speed based on the wheel's circumference or effective rolling radius. In existing technologies, some vehicle speed measuring devices use rollers or speed measuring wheels to contact the ground, tracks, or other surfaces being measured, and use encoders or speed sensors to collect the roller rotation information to obtain speed data. For example, document CN106610436A discloses a roller-type speed measuring device, which is pivotally connected to the vehicle body via a speed measuring wheel bracket and includes a buffer device to allow the speed measuring wheel bracket to swing slightly with road surface undulations, thereby improving the contact state between the speed measuring wheel and the ground. For example, document number CN220730247U discloses a speed measuring wheel device for a current meter calibration vehicle, which uses an articulated wheel frame and an elastic clamping assembly to keep the roller in stable contact with the track as much as possible during operation, so as to reduce slippage or jumping.

[0006] The aforementioned existing technologies can improve the contact stability of the speed measuring wheel or roller to some extent, but they generally still involve the speed measuring wheel or roller directly contacting the surface being measured, with the encoder collecting the wheel's rotation information. In actual road testing, the road surface may have undulations, seams, cracks, potholes, or localized unevenness, and the testing vehicle itself may also vibrate. These factors affect the contact state between the speed measuring wheel and the road surface, causing the speed measuring wheel to experience changes in ground pressure, momentary jumping, or slight slippage under certain operating conditions. Furthermore, the speed measuring wheel may wear down after long-term use, and the tire may also undergo some elastic deformation under pressure, resulting in a difference between its effective rolling radius and the theoretical value, thus affecting the accuracy of vehicle speed measurement based on wheel diameter conversion.

[0007] To improve the grounding stability of the speed measuring wheel, existing technologies typically employ structures such as counterweights, spring clamping, buffer mechanisms, or swing wheel frames to maintain the speed measuring wheel in contact with the measured surface as much as possible. However, in actual working conditions such as road dynamic deflection detection, relying solely on a single clamping structure or directly detecting wheel speed may still be insufficient to simultaneously ensure grounding stability, tire deformation compensation, and long-term measurement consistency. Especially during high-speed laser dynamic deflection detection, factors such as wheel jumps caused by changes in road surface smoothness, changes in effective wheel diameter due to pressure on the speed measuring wheel, changes in the tension of the transmission medium, and lateral offset can all affect the real-time vehicle speed measurement results. Therefore, it is necessary to improve the real-time vehicle speed measurement device used in road dynamic deflection detection vehicles to enhance its speed measurement stability and adaptability under actual road testing conditions. Summary of the Invention

[0008] The technical problem this invention aims to solve is: addressing the issue that existing speed measuring wheels used in road dynamic deflection detection vehicles are easily affected by road surface undulations, vehicle vibrations, wheel jumps, and changes in effective wheel diameter during actual testing, resulting in insufficient stability of real-time vehicle speed measurement. This invention provides a high-precision real-time vehicle speed measurement device and method, which improves grounding stability and measurement consistency during the vehicle speed measurement process through the combination of synchronous belt indirect speed measurement, semi-flexible tire buffer grounding, and a constant-pressure pneumatic downward pressing structure.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a high-precision real-time vehicle speed measuring device, comprising a constant pressure valve, a counterweight, a horizontal wheel frame, a horizontal hinge shaft, a vertical traction hinge shaft, a tension wheel, a main wheel frame, an encoder, a cylinder, a synchronous belt, a semi-flexible tire, a correction wheel, and an axle. The main wheel frame is hinged to the horizontal wheel frame via the horizontal hinge shaft, allowing the main wheel frame to swing up and down relative to the horizontal wheel frame. The vertical traction hinge shaft is located at one end of the main wheel frame and is used to connect to a road dynamic deflection detection vehicle. The axle is located on the main wheel frame, and the semi-flexible tire is mounted on the axle. The synchronous belt is arranged around the outer periphery of the semi-flexible tire, and its outer surface rolls in contact with the road surface and moves with the vehicle. The encoder is mounted on the main wheel frame and contacts the timing belt to collect the motion information of the timing belt and output a vehicle speed measurement signal; the tension pulley is set on the motion path of the timing belt and is used to compensate for the tension changes of the timing belt when the semi-flexible tire is compressed and deformed; the alignment pulley is set on the side of the timing belt to limit the lateral deviation of the timing belt relative to the semi-flexible tire, which is a tire that can produce elastic deformation when subjected to radial pressure. The cylinder is connected between the horizontal wheel frame and the main wheel frame or axle. The constant pressure valve is connected to the cylinder. The counterweight is set on the horizontal wheel frame. The constant pressure valve, cylinder and counterweight work together to apply and maintain downward pressure on the semi-flexible tire against the road surface.

[0010] Furthermore, the timing belt at least partially covers the outer circumference of the semi-flexible tire, the inner side of the timing belt is in contact with the outer circumference of the semi-flexible tire, and the outer side of the timing belt is used to contact the road surface.

[0011] Furthermore, the encoder has a speed measuring wheel that contacts the synchronous belt, and the speed measuring wheel presses against the non-grounded section of the synchronous belt to output a pulse signal according to the linear speed of the synchronous belt.

[0012] Furthermore, the tensioner is positioned above or to the side of the semi-flexible tire and presses against the timing belt to keep the timing belt in contact with the outer periphery of the semi-flexible tire.

[0013] Furthermore, the correction wheel is mounted on the main wheel frame and arranged close to the side of the synchronous belt to limit the axial displacement of the synchronous belt along the wheel axle. There are at least two correction wheels, which are located on both sides of the synchronous belt to form a lateral limiting structure on both sides of the synchronous belt.

[0014] Furthermore, the upper end of the cylinder is connected to the horizontal wheel frame, and the lower end of the cylinder is connected to the main wheel frame or wheel axle, so that the cylinder can drive the main wheel frame to swing around the horizontal hinge axis.

[0015] Furthermore, a constant pressure valve is installed on the counterweight or horizontal wheel frame. One end of the constant pressure valve is connected to the vehicle's air source, and the other end is connected to the cylinder to adjust the cylinder's output pressure. The counterweight is fixed on the horizontal wheel frame to provide basic downforce to the semi-flexible tire.

[0016] Furthermore, the main wheel frame is used to support the tension wheel, encoder, timing belt, semi-flexible tire, alignment wheel, and axle, allowing the tension wheel, encoder, timing belt, semi-flexible tire, alignment wheel, and axle to swing with the main wheel frame relative to the horizontal wheel frame.

[0017] The present invention also provides a high-precision real-time vehicle speed measurement method, comprising the following steps: S1. Device connection steps: Connect the vertical traction hinge shaft to the road dynamic deflection detection vehicle, so that the real-time vehicle speed measuring device moves with the road dynamic deflection detection vehicle. S2, Ground pressure adjustment steps: Apply the foundation downward pressure to the horizontal wheel frame through the counterweight, and adjust the output pressure of the cylinder through the constant pressure valve to keep the semi-flexible tire installed on the wheel axle pressed against the road surface with downward pressure; S3. Synchronous Rolling Step: When the vehicle is moving, the semi-flexible tire rolls with the vehicle. The synchronous belt surrounding the semi-flexible tire moves as the semi-flexible tire rolls into contact with the road surface. S4. Tension Compensation Step: Tension force is applied to the timing belt through the tensioner. When the semi-flexible tire undergoes radial deformation due to road surface undulations or changes in downforce, the tensioner changes the tension of the timing belt to compensate for the changes in the tension of the timing belt. S5. Correction and limiting steps: The lateral deviation of the timing belt relative to the semi-flexible tire is limited by the correction wheel; S6. Vehicle speed signal acquisition steps: The motion information of the synchronous belt is acquired by an encoder set on the main wheel frame, and the vehicle speed measurement signal is output. S7. Real-time vehicle speed calculation steps: Calculate the real-time vehicle speed of the vehicle being detected for road dynamic deflection based on the vehicle speed measurement signal output by the encoder.

[0018] Unlike structures that directly calculate vehicle speed from the rotational speed of the speed measuring wheel axle, this invention uses a synchronous belt as the vehicle speed acquisition medium. The synchronous belt is arranged around the outer periphery of the semi-flexible tire, with its grounding section located between the semi-flexible tire and the road surface. The encoder collects the motion information of the non-grounding section of the synchronous belt. Since the motion path and transmission state of the synchronous belt can be kept stable by the tensioning wheel, the influence of changes in the effective rolling radius of the tire on the vehicle speed measurement results can be reduced when the semi-flexible tire is subjected to pressure deformation or the road surface is uneven.

[0019] This invention does not improve the grounding state simply by adding counterweights or setting springs to press the speed measuring wheel. Instead, it uses a constant pressure valve, cylinder, and counterweight to form a downward pressure holding structure, combined with the main wheel frame hinge swing, semi-flexible tire buffer, synchronous belt tension compensation, and correction limit, so that the speed measuring device maintains a relatively stable synchronous belt operation under the road dynamic deflection detection conditions.

[0020] In S7, the encoder outputs a pulse signal within the sampling period. The linear displacement of the synchronous belt is calculated based on the number of pulses within the sampling period, the number of pulses per revolution of the encoder, and the circumference of the encoder's speed measuring wheel. The real-time vehicle speed is obtained based on the ratio of the linear displacement to the sampling period.

[0021] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a synchronous belt as an indirect speed measuring medium, replacing the traditional method of directly measuring vehicle speed with a speed measuring wheel. The synchronous belt is wrapped around the outer periphery of the semi-flexible tire and moves synchronously with the road surface as the vehicle travels. The encoder obtains the vehicle speed measurement signal by collecting the motion information of the synchronous belt. Since the vehicle speed measurement no longer relies solely on the effective rolling radius of the speed measuring wheel itself, it can reduce the impact of changes in the effective wheel diameter caused by tire pressure deformation, wear, or bumps during vehicle travel on the speed measurement results, which is beneficial to improving the stability and consistency of real-time vehicle speed measurement.

[0022] 2. This invention uses a semi-flexible tire instead of a regular rubber speed measuring tire. The semi-flexible tire has a certain elastic deformation capacity and support stiffness, which can buffer the impact caused by road undulations, seams, or local unevenness during vehicle operation, forming the first buffer structure to suppress / reduce wheel jumps. At the same time, the semi-flexible tire can reduce the local impact and abnormal friction experienced by the synchronous belt during operation, thereby reducing synchronous belt wear and improving the stability and service life of the synchronous belt.

[0023] 3. This invention employs a constant pressure valve, a counterweight, and a cylinder to form a downforce holding structure, replacing the traditional damping spring shock absorber or a single spring compression structure. The constant pressure valve can adjust and stabilize the cylinder output pressure, the counterweight can provide basic downforce, and the cylinder can continuously apply a force to the semi-flexible tire against the road surface according to the device's posture changes. Through this structure, the semi-flexible tire can maintain a relatively stable ground contact state under road undulations and vehicle vibration conditions, forming a second line of defense to suppress / reduce wheel jumps, thereby reducing instantaneous ground lift, jumping, or contact pressure fluctuations caused by insufficient road surface smoothness.

[0024] 4. This invention, through the coordination of a synchronous belt, a semi-flexible tire, a constant pressure maintaining structure, a tensioning pulley, and a correction pulley, can simultaneously improve the grounding stability, transmission stability, and measurement consistency of the speed measuring device. The tensioning pulley can compensate for the tension changes of the synchronous belt caused by the deformation of the semi-flexible tire under pressure, and the correction pulley can limit the lateral deviation of the synchronous belt, reducing the risk of the synchronous belt running off track or coming off track. Therefore, this invention can better adapt to the actual detection conditions of high-speed laser dynamic deflection detection vehicles, providing relatively stable real-time vehicle speed parameters for deflection data synchronization, detection position matching, and subsequent data processing. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the method flow of the present invention.

[0026] In the diagram: 1. Constant pressure air valve, 2. Counterweight, 3. Horizontal wheel frame, 4. Horizontal hinge shaft, 5. Vertical traction hinge shaft, 6. Tensioning wheel, 7. Main wheel frame, 8. Encoder, 9. Cylinder, 10. Synchronous belt, 11. Semi-flexible tire, 12. Correcting wheel, 13. Wheel axle. Detailed Implementation

[0027] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. Example 1

[0028] Please see Figure 1-2This invention provides a technical solution: a high-precision real-time vehicle speed measurement device and method. The device can be installed on a road dynamic deflection detection vehicle, and is especially suitable for high-speed laser dynamic deflection detection equipment. It is used to obtain the vehicle speed in real time during the vehicle's movement. The device includes a constant pressure air valve 1, a counterweight 2, a horizontal wheel frame 3, a horizontal hinge shaft 4, a vertical traction hinge shaft 5, a tension wheel 6, a main wheel frame 7, an encoder 8, a cylinder 9, a synchronous belt 10, a semi-flexible tire 11, a correction wheel 12, and a wheel axle 13.

[0029] The main wheel frame 7 serves as the main load-bearing structure of the speed measuring device, used to install and support the tension wheel 6, encoder 8, synchronous belt 10, semi-flexible tire 11, correction wheel 12, and axle 13. The main wheel frame 7 is hinged to the horizontal wheel frame 3 via the horizontal hinge shaft 4, allowing the main wheel frame 7 to swing up and down relative to the horizontal wheel frame 3. Through this structure, when the vehicle being tested travels on a road surface with undulations, seams, or local unevenness, the main wheel frame 7 can adaptively swing with changes in road surface height, thereby reducing the impact of rigid connections on the stability of speed measurement.

[0030] The vertical traction hinge 5 is located at one end of the main wheel frame 7 and is used to connect with the road dynamic deflection detection vehicle. The vertical traction hinge 5 enables the speed measuring device to move forward with the detection vehicle and allows the speed measuring device to adjust its angle relative to the detection vehicle within a certain range to adapt to changes in the vehicle's driving direction or the vehicle's posture. The vertical traction hinge 5 can be connected to the detection vehicle through a connecting lug, pin, bushing, or spherical bearing, as long as it can achieve traction connection and allow the speed measuring device to rotate adaptively.

[0031] The axle 13 is mounted on the main wheel frame 7, and the semi-flexible tire 11 is mounted on the axle 13. The axle 13 can be mounted on the lower part of the main wheel frame 7 via bearings, allowing the semi-flexible tire 11 to rotate freely around the axle 13. The semi-flexible tire 11 is a tire that can generate elastic deformation when subjected to radial pressure and recover after the pressure decreases. The semi-flexible tire 11 can be made of polyurethane, solid rubber, rubber composite material, or other materials with elasticity and support stiffness. The semi-flexible tire 11 can both buffer road impacts and provide stable support for the timing belt 10.

[0032] The timing belt 10 is arranged around the outer periphery of the semi-flexible tire 11; the inner side of the timing belt 10 is in contact with the outer circumferential surface of the semi-flexible tire 11, and the outer side of the timing belt 10 is used to contact the road surface; when the vehicle is moving, the grounding section of the timing belt 10 is located between the semi-flexible tire 11 and the road surface, and the semi-flexible tire 11 forms rolling contact with the road surface through the timing belt 10; that is, the road surface does not directly contact the outer circumferential surface of the semi-flexible tire 11, but indirectly drives the semi-flexible tire 11 to roll through the timing belt 10, and at the same time, the timing belt 10 serves as the motion medium for the encoder 8 to collect vehicle speed information.

[0033] The timing belt 10 can be a toothed timing belt, a wear-resistant flat belt, a transmission belt with anti-slip texture, or other belt-like components that can stably transmit linear speed. In one possible embodiment, the timing belt 10 is an annular belt with teeth or anti-slip texture on the inner side, the inner side of which is in contact with the outer peripheral surface of the semi-flexible tire 11, and the outer side is in contact with the road surface. The timing belt 10 should have appropriate wear resistance and flexibility to adapt to continuous rolling and local road impact during road testing.

[0034] The encoder 8 is mounted on the main wheel frame 7 and contacts the synchronous belt 10. The encoder 8 can be an incremental encoder, an absolute encoder, or other rotational sensor capable of outputting speed signals. The encoder 8 has a speed measuring wheel that contacts the synchronous belt 10 and presses against the non-grounded section of the synchronous belt 10. When the synchronous belt 10 moves with the test vehicle, the synchronous belt 10 drives the speed measuring wheel of the encoder 8 to rotate. The encoder 8 converts the rotation information of the speed measuring wheel into a pulse signal or a digital speed signal and outputs it to the data acquisition system of the road dynamic deflection detection equipment.

[0035] Preferably, the encoder 8 is fixed on the main wheel frame 7, and the speed measuring wheel of the encoder 8 is pressed against the non-grounded section of the synchronous belt 10 through a spring mechanism, so that the encoder 8 can stably collect the motion information of the synchronous belt 10. The spring mechanism can be a compression spring, torsion spring, tension spring or elastic pressure arm structure, as long as it can keep the speed measuring wheel of the encoder 8 in contact with the synchronous belt 10.

[0036] Since the encoder 8 collects the motion information of the timing belt 10, rather than directly collecting the rotation information of the semi-flexible tire 11 or the axle 13, it can reduce the impact of the change in the effective rolling radius of the semi-flexible tire 11 on the vehicle speed calculation result when the semi-flexible tire 11 undergoes a certain radial deformation due to pressure, wear or road impact. The linear velocity of the timing belt 10 corresponds to the driving speed of the detected vehicle relative to the road surface, and the encoder 8 outputs the vehicle speed measurement signal based on the linear velocity of the timing belt 10.

[0037] The tension pulley 6 is positioned on the movement path of the timing belt 10. The tension pulley 6 can be mounted on the main wheel frame 7 and located above or to the side of the semi-flexible tire 11. The tension pulley 6 abuts against the timing belt 10 to apply tension to the timing belt 10, keeping the timing belt 10 in contact with the outer periphery of the semi-flexible tire 11. When the semi-flexible tire 11 undergoes radial deformation due to road surface undulations, changes in downforce, or vehicle vibration, the tension of the timing belt 10 may change. The tension pulley 6 can compensate for the changes in the tension of the timing belt 10 through its own position adjustment or elastic tensioning structure, preventing the timing belt 10 from becoming too loose, slipping, or detaching from the semi-flexible tire 11.

[0038] Preferably, the tensioning pulley 6 is fixed to the main pulley frame 7 and applies preload to the timing belt 10 through a spring mechanism to keep the timing belt 10 taut. When the semi-flexible tire 11 changes shape due to bumps or pressure, the tensioning pulley 6 can absorb or compensate for the change in the allowance of the timing belt 10. The spring mechanism can be a spring tensioning mechanism, a torsion spring tensioning mechanism, a gas spring tensioning mechanism, or a screw-adjustable tensioning mechanism. In one specific embodiment, the tensioning pulley 6 is mounted on a swingable tensioning arm, which is connected to the main pulley frame 7 through a spring. The spring applies preload to the tensioning arm, causing the tensioning pulley 6 to continuously press against the timing belt 10. In another specific embodiment, the tensioning pulley 6 is mounted on an adjusting seat with an elongated hole. The position of the tensioning pulley 6 relative to the timing belt 10 is changed by adjusting the screw to obtain a suitable timing belt tension.

[0039] The alignment wheel 12 is disposed on the side of the timing belt 10 to limit the lateral deviation of the timing belt 10 relative to the semi-flexible tire 11. The alignment wheel 12 can be disposed on the main wheel frame 7 and arranged close to the side of the timing belt 10. Preferably, the main wheel frame 7 is provided with a crossbar, and the alignment wheel 12 is mounted on the crossbar and located on the side of the timing belt 10 to limit the axial deviation of the timing belt 10 along the wheel axle 13. In a preferred embodiment, there are at least two alignment wheels 12, and the at least two alignment wheels 12 are respectively located on both sides of the timing belt 10 to form a lateral limiting structure on both sides of the timing belt 10. If the timing belt 10 deviates along the axial direction of the wheel axle 13 during operation, the alignment wheel 12 can limit the side of the timing belt 10, thereby reducing the risk of the timing belt 10 running off track or detaching from the semi-flexible tire 11.

[0040] The cylinder 9 is connected between the horizontal wheel frame 3 and the main wheel frame 7, the wheel axle support seat or the wheel axle mounting seat; the upper end of the cylinder 9 can be connected to the horizontal wheel frame 3, and the lower end of the cylinder 9 can be connected to the lower part of the main wheel frame 7, the wheel axle support seat or the wheel axle mounting seat, so that the cylinder 9 can perform extension and retraction movements with the swing of the main wheel frame 7, and apply downward pressure to the location of the main wheel frame 7 or the wheel axle 13; through this structure, the cylinder 9 can keep the semi-flexible tire 11 pressed against the road surface.

[0041] In one specific embodiment, the upper end of the cylinder body of the cylinder 9 is fixed or hinged to the horizontal wheel frame 3, and the lower end of the guide rod of the cylinder 9 is connected to the wheel axle 13, the wheel axle support seat or the lower part of the main wheel frame 7 through a connecting rod, so that the cylinder 9 can apply a force to the semi-flexible tire 11 to the road surface through the connecting rod; when the connecting rod connection method is adopted, the connecting rod can be hinged to the end of the guide rod of the cylinder 9 and hinged to the wheel axle support seat or the lower part of the main wheel frame 7 to avoid jamming when the main wheel frame 7 swings.

[0042] The constant pressure valve 1 is connected to the cylinder 9; the constant pressure valve 1 can be installed on the counterweight 2 or on the horizontal wheel frame 3; the air inlet of the constant pressure valve 1 is connected to the on-board air source / test vehicle air source of the road dynamic deflection detection vehicle, and the air outlet is connected to the cylinder 9 to adjust and stabilize the output pressure of the cylinder 9; the counterweight 2 is set on the horizontal wheel frame 3 to provide basic downforce; the constant pressure valve 1, the cylinder 9 and the counterweight 2 work together to keep the semi-flexible tire 11 pressed against the road surface by the synchronous belt 10; the counterweight 2 provides relatively stable gravity loading, the cylinder 9 provides adjustable pneumatic loading, and the constant pressure valve 1 is used to stabilize the output pressure of the cylinder 9. The cooperation of the three can improve the contact state between the semi-flexible tire 11 and the road surface.

[0043] In one feasible implementation, the counterweight 2 is fixed to the horizontal wheel frame 3, and the constant pressure air valve 1 is installed on the counterweight 2 or the horizontal wheel frame 3 to facilitate air circuit connection and pressure adjustment. The air source can come from the compressed air system of the test vehicle or from an independent air source. The output pressure of the constant pressure air valve 1 is adjusted according to the speed of the test vehicle, road conditions, size of the semi-flexible tire 11 and tension of the timing belt 10, so that the ground section of the timing belt 10 can stably adhere to the road surface, while avoiding excessive downward pressure that would cause the timing belt 10 to wear too quickly.

[0044] During assembly, the semi-flexible tire 11 can be installed on the axle 13 first, and then the axle 13 can be installed on the lower part of the main wheel frame 7 through the bearing; then the timing belt 10 can be sleeved on the outer circumference of the semi-flexible tire 11, so that the inner side of the timing belt 10 is in contact with the outer circumference of the semi-flexible tire 11; then the tensioning wheel 6 can be installed, and the position or preload of the tensioning wheel 6 can be adjusted to keep the timing belt 10 in a proper tension state; then the encoder 8 can be installed, so that the speed measuring wheel of the encoder 8 presses against the non-grounded section of the timing belt 10; then the correction wheel 12 can be installed, so that the correction wheel 12 is close to the side of the timing belt 10 but does not generate excessive clamping resistance to the timing belt 10; finally, the main wheel frame 7 can be connected to the horizontal wheel frame 3 through the horizontal hinge shaft 4, and the cylinder 9, the constant pressure valve 1, and the counterweight 2 can be installed.

[0045] In use, the vertical traction hinge 5 is connected to the road dynamic deflection detection vehicle, allowing the device to move forward with the vehicle. Before detection, the output pressure of the cylinder 9 is adjusted by the constant pressure valve 1, and the appropriate downward pressure is determined according to the road conditions and detection speed, so that the grounding section of the synchronous belt 10 can stably contact the road surface. When the vehicle is moving, the outer side of the synchronous belt 10 contacts the road surface and moves with the vehicle. The synchronous belt 10 drives the speed measuring wheel of the encoder 8 to rotate, and the encoder 8 outputs a vehicle speed measurement signal corresponding to the linear velocity of the synchronous belt 10. The data acquisition system of the road dynamic deflection detection equipment receives the signal output by the encoder 8 and calculates the real-time vehicle speed based on the signal.

[0046] like Figure 2As shown, this embodiment also provides a high-precision real-time vehicle speed measurement method, implemented using the aforementioned high-precision real-time vehicle speed measurement device; the method includes the following steps: S1. Device connection steps: Connect the vertical traction hinge 5 to the road dynamic deflection detection vehicle so that the real-time vehicle speed measuring device moves with the road dynamic deflection detection vehicle; after connection, it should be ensured that the main wheel frame 7 can swing up and down relative to the horizontal wheel frame 3 through the horizontal hinge 4, and that the vertical traction hinge 5 can allow the speed measuring device to make adaptive adjustments as the vehicle travels in different directions. S2. Ground pressure adjustment steps: Apply the foundation downward pressure to the horizontal wheel frame 3 through the counterweight block 2, and adjust the output pressure of the cylinder 9 through the constant pressure valve 1, so that the semi-flexible tire 11 installed on the wheel axle 13 maintains the downward pressure on the road surface through the synchronous belt 10; During adjustment, the grounding section of the synchronous belt 10 can stably contact the road surface, and the synchronous belt 10 does not produce obvious slippage or excessive wear. S3. Synchronous Rolling Step: When the vehicle is driving, the ground contact section of the synchronous belt 10 contacts the road surface, and the semi-flexible tire 11 forms rolling contact with the road surface through the synchronous belt 10, so that the synchronous belt 10 moves with the vehicle. Since the synchronous belt 10 is in contact with the road surface, the linear velocity of the synchronous belt 10 can reflect the driving speed of the vehicle relative to the road surface. S4. Tensioning compensation step: Tensioning force is applied to the timing belt 10 through the tensioning pulley 6; when the semi-flexible tire 11 undergoes radial deformation due to road surface undulations, vehicle vibration, or changes in downforce, the tensioning pulley 6 compensates for the tension changes of the timing belt 10 through position changes or elastic pre-tensioning, so that the timing belt 10 maintains a relatively stable tension state. S5. Correction and limiting steps: The correction wheel 12 limits the lateral deviation of the timing belt 10 relative to the semi-flexible tire 11; if the timing belt 10 deviates along the axial direction of the wheel axle 13 during operation, the correction wheel 12 limits the side of the timing belt 10, thereby reducing the risk of the timing belt 10 running off track or separating from the semi-flexible tire 11. S6. Vehicle speed signal acquisition steps: The encoder 8, which is set on the main wheel frame 7, acquires the motion information of the synchronous belt 10 and outputs the vehicle speed measurement signal; the speed measuring wheel of the encoder 8 presses against the non-grounded section of the synchronous belt 10. When the synchronous belt 10 moves, it drives the speed measuring wheel to rotate, and the encoder 8 outputs a pulse signal or a digital speed signal. S7. Real-time vehicle speed calculation steps: Calculate the real-time vehicle speed of the vehicle for road dynamic deflection detection based on the vehicle speed measurement signal output by encoder 8; when encoder 8 outputs a pulse signal, the linear speed of synchronous belt 10 can be calculated based on the number of pulses in the sampling period, the number of pulses per encoder revolution, the circumference of the encoder speed measuring wheel, and the sampling period, and this linear speed is used as the real-time vehicle speed of the detection vehicle.

[0047] In one specific calculation method, the real-time vehicle speed v is calculated according to the following formula: v = n × C / N / T Where v is the real-time vehicle speed, n is the number of pulses output by encoder 8 within the sampling period T, C is the circumference of the speed measuring wheel of encoder 8, N is the number of pulses output by encoder 8 per revolution, and T is the sampling period; if it is necessary to output the vehicle speed in km / h, it can be converted by multiplying by 3.6 after calculating the speed in m / s.

[0048] To improve the stability of vehicle speed calculation, the output signal of encoder 8 can also be filtered. For example, moving average filtering, median filtering, or abnormal pulse elimination methods can be used to smooth abnormal speed fluctuations caused by road impacts in a short period of time. The filtering process does not change the basic principle of this invention of collecting vehicle speed information through synchronous belt 10, but is only used to improve the stability of the output vehicle speed signal.

[0049] During the testing process, when there are local undulations in the road surface, the semi-flexible tire 11 first absorbs part of the impact through its own elastic deformation, forming the first buffer effect; at the same time, the main wheel frame 7 can swing up and down around the horizontal hinge axis 4 to adapt to changes in road height; the cylinder 9 continuously outputs a relatively stable downward pressure under the action of the constant pressure valve 1, and the counterweight 2 provides the basic downward pressure, thus forming the second anti-jumping wheel structure; through the above structural cooperation, the possibility of instantaneous ground lift or significant fluctuations in contact pressure between the synchronous belt 10 ground contact section and the road surface can be reduced.

[0050] When the semi-flexible tire 11 undergoes radial deformation due to pressure, the tensioning wheel 6 can compensate for the tension changes of the timing belt 10, ensuring that the timing belt 10 remains in contact with the semi-flexible tire 11 and that the speed measuring wheel of the encoder 8 can continuously contact the timing belt 10. When the timing belt 10 is running at high speed or subjected to lateral disturbances, the correction wheel 12 restricts the timing belt 10 from axially shifting along the wheel axle 13, reducing the risk of the timing belt 10 running off course. Thus, the present invention can improve the stability of the timing belt 10's operating state during the dynamic bending detection of vehicles on the road.

[0051] In another embodiment, the semi-flexible tire 11 can be selected from tires of different hardness or materials according to the speed of the detection vehicle and road conditions; for example, under the condition of relatively flat road surface and high detection speed, a semi-flexible tire with high support stiffness can be selected; under the condition of obvious road surface undulation, a semi-flexible tire with strong elastic deformation ability can be selected; the specific material, diameter and width of the semi-flexible tire 11 can be selected according to the installation space of the detection vehicle, the size of the timing belt 10 and the expected downforce.

[0052] In another embodiment, the constant pressure valve 1 and cylinder 9 can also be replaced with other loading mechanisms that can provide stable downforce, such as a hydraulic constant pressure mechanism, an electric push rod constant force loading mechanism, a gas spring loading mechanism, or a spring and damper combination loading mechanism; as long as the loading mechanism can keep the semi-flexible tire 11 pressed against the road surface by the timing belt 10 and can adapt to the up and down swing of the main wheel frame 7, the basic purpose of the present invention can be achieved.

[0053] In another embodiment, the speed measuring wheel of the encoder 8 can directly press against the non-grounded section of the synchronous belt 10, or it can be connected to the synchronous belt 10 through a synchronous pulley, friction wheel or coupling; the encoder 8 can be installed on the side, top or near the tensioning pulley 6 of the main pulley frame 7, as long as the encoder 8 can reliably collect the motion information of the synchronous belt 10.

[0054] In another embodiment, the tensioning wheel 6 can be one or more; the multiple tensioning wheels 6 can be arranged at different positions of the timing belt 10 to improve the wrapping stability of the timing belt 10 and the semi-flexible tire 11; the correction wheel 12 can also be one, two or more, and the outer periphery of the correction wheel 12 can be provided with a limiting groove, a stop or a guide surface to further improve the anti-deviation effect of the timing belt 10.

[0055] In another embodiment, the outer surface of the timing belt 10 may be provided with a wear-resistant layer, anti-slip texture, or rubber coating to improve its frictional stability with the road surface; the inner surface of the timing belt 10 may be provided with a toothed structure, anti-slip texture, or flexible bonding layer to improve its bonding stability with the outer peripheral surface of the semi-flexible tire 11; the timing belt 10 may be a closed-loop structure or may be connected by a joint to form a ring structure.

[0056] In actual manufacturing and debugging, those skilled in the art can select the parameters of each component according to the installation space and detection speed of the vehicle being tested. As an exemplary implementation condition, the diameter of the semi-flexible tire 11 can be determined according to the installation space at the bottom of the vehicle, the width of the timing belt 10 can be matched with the width of the semi-flexible tire 11, the resolution of the encoder 8 can be selected according to the required vehicle speed sampling accuracy, and the output pressure of the cylinder 9 can be adjusted according to the total mass of the device, the mass of the counterweight 2, and the road contact requirements. All of the above parameters can be selected according to the actual working conditions and do not affect the implementation of the present invention.

[0057] Through the above structure and method, the present invention does not directly rely on the axle rotation speed of the semi-flexible tire 11 to calculate the vehicle speed during operation. Instead, it uses the synchronous belt 10 as an indirect speed measuring medium, and the encoder 8 collects the motion information of the synchronous belt 10. The semi-flexible tire 11 is used to buffer road impacts, the constant pressure valve 1, the cylinder 9 and the counterweight 2 are used to maintain a relatively stable downward pressure, the tensioning wheel 6 is used to compensate for the tension changes of the synchronous belt 10, and the correction wheel 12 is used to limit the lateral deviation of the synchronous belt 10. The components cooperate with each other, enabling the present invention to achieve real-time vehicle speed measurement during the dynamic deflection detection of vehicles on the road, and to adapt to a certain degree of road surface undulation and vehicle vibration.

[0058] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A high-precision real-time vehicle speed measuring device, comprising a constant pressure air valve (1), a counterweight (2), a horizontal wheel frame (3), a horizontal hinge shaft (4), a vertical traction hinge shaft (5), a tension wheel (6), a main wheel frame (7), an encoder (8), a cylinder (9), a synchronous belt (10), a semi-flexible tire (11), a correction wheel (12), and a wheel axle (13), characterized in that: The main wheel frame (7) is hinged to the horizontal wheel frame (3) via the horizontal hinge shaft (4), so that the main wheel frame (7) can swing up and down relative to the horizontal wheel frame (3); the vertical traction hinge shaft (5) is set at one end of the main wheel frame (7) for connecting with the road dynamic deflection detection vehicle; the wheel axle (13) is set on the main wheel frame (7), and the semi-flexible tire (11) is installed on the wheel axle (13); the timing belt (10) is set around the outer periphery of the semi-flexible tire (11), and its outer side is in rolling contact with the road surface and moves with the vehicle. The encoder (8) is mounted on the main wheel frame (7) and contacts the timing belt (10). The tension wheel (6) is mounted on the movement path of the timing belt (10). The correction wheel (12) is mounted on the side of the timing belt (10) to limit the lateral offset of the timing belt (10) relative to the semi-flexible tire (11). The cylinder (9) is connected between the horizontal wheel frame (3) and the main wheel frame (7) or the wheel axle (13). The constant pressure valve (1) is connected to the cylinder (9). The counterweight (2) is set on the horizontal wheel frame (3). The constant pressure valve (1), the cylinder (9) and the counterweight (2) are used together to apply and maintain the downward pressure on the semi-flexible tire (11) against the road surface.

2. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The timing belt (10) covers at least part of the outer circumferential surface of the semi-flexible tire (11), the inner side of the timing belt (10) is in contact with the outer circumference of the semi-flexible tire (11), and the outer side of the timing belt (10) is used to contact the road surface.

3. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The encoder (8) has a speed measuring wheel that contacts the synchronous belt (10), and the speed measuring wheel presses against the non-grounded section of the synchronous belt (10) to output a pulse signal according to the linear velocity of the synchronous belt (10).

4. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The tensioner (6) is located above or to the side of the semi-flexible tire (11) and presses against the timing belt (10) so that the timing belt (10) remains in contact with the outer periphery of the semi-flexible tire (11).

5. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The correction wheel (12) is set on the main wheel frame (7) and arranged close to the side of the synchronous belt (10). There are at least two correction wheels (12), and the at least two correction wheels (12) are located on both sides of the synchronous belt (10) to form a lateral limiting structure on both sides of the synchronous belt (10).

6. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The upper end of the cylinder (9) is connected to the horizontal wheel frame (3), and the lower end of the cylinder (9) is connected to the main wheel frame (7) or the wheel axle (13), so that the cylinder (9) can drive the main wheel frame (7) to swing around the horizontal hinge axis (4).

7. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The constant pressure valve (1) is set on the counterweight (2) or the horizontal wheel frame (3). One end of the constant pressure valve (1) is connected to the vehicle air source, and the other end is connected to the cylinder (9) to adjust the output pressure of the cylinder (9). The counterweight (2) is fixed on the horizontal wheel frame (3) to provide basic downforce to the semi-flexible tire (11).

8. The high-precision real-time vehicle speed measuring device according to claim 1, characterized in that: The main wheel frame (7) is used to support the tension wheel (6), encoder (8), timing belt (10), semi-flexible tire (11), correction wheel (12) and axle (13), so that the tension wheel (6), encoder (8), timing belt (10), semi-flexible tire (11), correction wheel (12) and axle (13) can swing with the main wheel frame (7) relative to the horizontal wheel frame (3).

9. A high-precision real-time vehicle speed measurement method, characterized in that, The high-precision real-time vehicle speed measuring device according to any one of claims 1-8 includes the following steps: S1. Device connection steps: Connect the vertical traction hinge shaft (5) to the road dynamic deflection detection vehicle so that the real-time vehicle speed measuring device moves with the road dynamic deflection detection vehicle. S2, Ground pressure adjustment steps: Apply the foundation pressure to the horizontal wheel frame (3) through the counterweight (2), and adjust the output pressure of the cylinder (9) through the constant pressure valve (1) so that the semi-flexible tire (11) installed on the wheel axle (13) maintains the downward pressure on the road surface; S3, Synchronous Rolling Step: When the vehicle is traveling, the semi-flexible tire (11) rolls with the vehicle. The synchronous belt (10) surrounding the semi-flexible tire (11) moves with the rolling contact between the semi-flexible tire (11) and the road surface. S4, tension compensation step: tension force is applied to the timing belt (10) through the tensioning wheel (6). When the semi-flexible tire (11) undergoes radial deformation due to road surface undulation or downforce changes, the tensioning wheel (6) changes the tension state of the timing belt (10) to compensate for the tension change of the timing belt (10). S5, Correction and Limitation Step: The lateral offset of the timing belt (10) relative to the semi-flexible tire (11) is limited by the correction wheel (12); S6, Vehicle speed signal acquisition steps: The motion information of the synchronous belt (10) is acquired by the encoder (8) set on the main wheel frame (7), and the vehicle speed measurement signal is output; S7. Real-time vehicle speed calculation steps: Calculate the real-time vehicle speed of the vehicle for road dynamic deflection detection based on the vehicle speed measurement signal output by the encoder (8).

10. The method according to claim 9, characterized in that: In S7, the encoder (8) outputs a pulse signal during the sampling period. The linear displacement of the synchronous belt (10) is calculated based on the number of pulses during the sampling period, the number of pulses per revolution of the encoder (8), and the circumference of the speed measuring wheel of the encoder (8). The real-time vehicle speed is obtained based on the ratio of the linear displacement to the sampling period.

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