Wireless ground sensing vehicle detection device and method

Abstract

The present invention discloses a wireless ground-sensing vehicle detection device, comprising a vehicle detector, a ground-sensing coil, a triggering device, and a detector. The triggering device, the ground-sensing coil, and the detector are sequentially installed on the road along the direction of travel of the vehicle. The vehicle detection device is provided with a triggering device in front of the ground-sensing coil and a detector behind the ground-sensing coil. The triggering device is used to detect whether a vehicle is approaching the ground-sensing coil and to determine the distance between vehicles. When a vehicle approaches the ground-sensing coil, the ground-sensing coil is activated. When the distance between vehicles is too close, the detector is activated to detect the number, moving speed, and length of vehicles, thereby avoiding interference of the rear vehicle in detecting the front vehicle and ensuring the accuracy of detection. When the distance between vehicles is far, only the ground-sensing coil is activated, which can ensure the accuracy of detection and achieve the purpose of saving power. The vehicle detection device can also realize adaptive adjustment of the vehicle detection device to the environmental magnetic field, expanding its scope of application.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle detection, and more particularly to a wireless ground-sensing vehicle detection device and method. Background Art

[0002] In the smart parking industry, vehicle detectors are familiar to everyone. Due to different application technologies, they can be divided into toroidal coil vehicle detectors, ultrasonic sensor vehicle detectors, radar detection vehicle detectors, video detection vehicle detectors, etc.

[0003] Among these, the most widely used type is the toroidal coil vehicle detector. It uses a ground-sensing coil buried beneath the lane. Passing vehicles cause changes in the coil's magnetic field. The detector can then calculate parameters such as vehicle flow, speed, and length based on this magnetic field change.

[0004] In smart parking systems, ground-sensing vehicle detectors primarily serve as triggers to detect whether a vehicle is on the lane. Due to their mature technology, ease of installation, and low cost, ground-sensing vehicle detectors are widely used in the parking industry.

[0005] However, ground-sensing vehicle detectors also have their shortcomings. When there is a lot of traffic and the distance between vehicles is small, the front of the rear vehicle and the rear of the front vehicle may be within the sensing range of the ground-sensing coil at the same time. That is, the rear vehicle interferes with the detection of the front vehicle. At this time, the detection accuracy will decrease, and the number of passing vehicles cannot be accurately detected. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a wireless ground-sensing vehicle detection device and method, which can accurately detect the number of passing vehicles even when the distance between vehicles is relatively close.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A wireless ground-sensing vehicle detection device includes a vehicle detector, a ground-sensing coil, and a trigger device, wherein the trigger device is installed in the edge area of ​​the road surface, and is used to sense the pressure from the wheel and is triggered when the wheel pressure is applied. When the trigger device is triggered, a trigger signal is sent; and a first detector, wherein the first detector is used to be buried in the middle area of ​​the road surface, the first detector includes a shell and a first sensor arranged on the shell, and the first sensor is used to detect whether there is a vehicle above it. When there is a vehicle above it, the first sensor outputs a first level signal; when there is no vehicle above it, the first sensor outputs a second level signal; the ground-sensing coil is buried Located in the middle area of ​​the road surface, it is used to sense whether a vehicle passes over it. The ground sensing coil, feeder and capacitor inside the vehicle detector constitute an LC oscillation circuit, and the LC oscillation circuit is connected to and controlled by the vehicle detector; the trigger device is connected to and controlled by the vehicle detector; the first detector is connected to and controlled by the vehicle detector; the trigger device, ground sensing coil and first detector are installed on the road in sequence along the direction of vehicle travel, and there is a distance between the trigger device and the ground sensing coil, so that the trigger device is away from the magnetic field range of the ground sensing coil; there is also a distance between the first detector and the ground sensing coil, so that the first detector is away from the magnetic field range of the ground sensing coil.

[0009] As a preferred solution: it also includes a second detector, which is connected to and controlled by the vehicle detector. The second detector is used to be buried in the middle area of ​​the road surface, and the second detector is located behind the first detector. The second detector includes a shell and a second sensor arranged on the shell. The second sensor is used to detect whether there is a vehicle above it. When there is a vehicle above it, the second sensor outputs a third level signal; when there is no vehicle above it, the second sensor outputs a fourth level signal.

[0010] As a preferred solution: the first sensor and the second sensor are infrared sensors or distance sensors.

[0011] As a preferred solution: a switch unit is installed at one end of the ground sensing coil, a jumper is connected to each coil layer of the ground sensing coil, each jumper is connected in parallel to an LC oscillation circuit, a switch unit is installed on each jumper, the switch unit is connected to and controlled by a vehicle detector, the vehicle detection device also includes a magnetic field sensor, the magnetic field sensor is installed within the magnetic field range of the ground sensing coil, and the magnetic field sensor is connected to and controlled by the vehicle detector.

[0012] As a preferred embodiment: the trigger device is strip-shaped, which includes an upper shell and a lower shell, the bottom edge of the upper shell is bent inward to form a curling edge, and the top edge of the lower shell is bent inward to form a curling edge, and an annular elastic ring is arranged between the upper and lower curling edges along the circumference of the trigger device, the top and bottom surfaces of the elastic ring are respectively bonded and fixed to the curling edge of the upper shell and the curling edge of the lower shell by waterproof glue, the elastic ring separates the upper shell and the lower shell, so that a vertical activity space is formed between the two, and a plurality of vertical connecting bolts are arranged on the inner side of the elastic ring along the circumference of the trigger device, the lower end of the connecting bolt is connected and fixed to the curling edge of the lower shell, a through hole is provided on the curling edge of the upper shell, the upper end of the connecting bolt passes through the through hole and the upper end of the connecting bolt has a bolt head, a trigger switch is installed inside the lower shell, and a push rod is installed in the upper shell, and the push rod is aligned with the trigger switch.

[0013] As a preferred solution: an annular inner sealing ring is arranged between the elastic ring and the connecting bolt along the circumference of the trigger device. The inner sealing ring is a membrane structure, and its top and bottom surfaces are sealed and bonded to the curled edges of the upper shell and the lower shell respectively. A first magnet is installed at the bottom of the upper shell, and a second magnet is installed at the top of the lower shell, and the first magnet and the second magnet repel each other.

[0014] As a preferred solution: the vehicle detector includes a main control module, and also includes a dial switch connected to the main control module, a wireless communication module, a storage module, an oscillation circuit, a storage module and a power management module.

[0015] A wireless ground sensing vehicle detection method comprises the following steps:

[0016] S1. A trigger device is provided in front of the ground sensing coil, and a first detector is provided behind the ground sensing coil;

[0017] S2. When the trigger device is triggered by a vehicle, the ground sensing coil is activated to detect the vehicle; when a vehicle passes the ground sensing coil, the trigger device is triggered again, and the first vehicle detector is activated to detect the number of vehicles through the first detector;

[0018] S3. When the trigger device is not triggered again for a period of time, the ground sensing coil is controlled to stop working.

[0019] As a preferred solution: in step S1, a second detector is also provided behind the first detector; in step S2, when a vehicle passes through the ground sensing coil, the trigger device is triggered again, and the first detector and the second detector are started, and the number of vehicles is detected by the first detector, and the moving speed and length of the vehicle are calculated based on the distance between the first detector and the second detector and the time point when the vehicle passes through the first detector and the second detector.

[0020] As a preferred solution: a trigger device is set in front of the ground sensing coil, and a detector is set behind the ground sensing coil. The magnetic field strength of the environment around the ground sensing coil is also detected, and the detection result is compared with the trigger magnetic field strength of different turns of the ground sensing coil calibrated in advance. When the two are close, the number of turns of the ground sensing coil is changed, and the trigger magnetic field strength of the ground sensing coil is switched to a higher level.

[0021] Compared with the prior art, the advantages of the present invention are: the vehicle detection device, by arranging a trigger device in front of the ground sensing coil and a detector behind the ground sensing coil, detects whether there is a vehicle approaching the ground sensing coil and judges the distance between vehicles through the trigger device, starts the ground sensing coil when a vehicle approaches the ground sensing coil, and starts the detector when the distance between vehicles is too close to detect the number, moving speed and length of vehicles, thereby avoiding interference of the rear vehicle in the detection of the front vehicle and ensuring the accuracy of detection; when the distance between vehicles is far, only the ground sensing coil is started, which can not only ensure the accuracy of detection but also achieve the purpose of saving power; in addition, when no vehicle approaches the ground sensing coil for a long time, the ground sensing coil automatically goes into sleep mode, which saves more power; the vehicle detection device can also realize adaptive adjustment of the vehicle detection device to the environmental magnetic field, thereby expanding its scope of application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the vehicle detection device in Example 1;

[0023] Figure 2 Schematic diagram of the layout of the vehicle detection system in Example 1;

[0024] Figure 3 Schematic diagram of the structure of the ground sensing coil in Example 1;

[0025] Figure 4 Schematic diagram of the structure of the trigger device in Example 1;

[0026] Figure 5 This is a circuit diagram of the vehicle detection device in Example 1.

[0027] Explanation of the accompanying drawings: 1. Ground sensing coil; 2. Vehicle detector; 3. Trigger device; 301. Upper shell; 302. Lower shell; 303. Curled edge; 304. Through hole; 305. Connecting bolt; 306. Elastic ring; 307. Inner sealing ring; 308. First magnet; 309. Second magnet; 310. Trigger switch; 311. Push rod; 4. First detector; 5. First sensor; 6. Second detector; 7. Second sensor; 8. Vehicle; 9. Lane; 10. Magnetic field sensor; 11. Jumper; 12. Switch unit. DETAILED DESCRIPTION

[0028] Reference Figure 1A wireless ground sensing vehicle detection device includes a vehicle detector 2, a ground sensing coil 1, a trigger device 3 and a first detector 4.

[0029] The trigger device 3 is in a strip shape and is installed at the edge area of ​​the road surface. It is used to sense the pressure from the wheels and is triggered when it receives the pressure from the wheels. When the trigger device 3 is triggered, a trigger signal is sent out.

[0030] The first detector 4 is used to be buried in the middle area of ​​the road surface. The first detector 4 includes a shell and a first sensor 5 arranged on the shell. The first sensor 5 is used to detect whether there is a vehicle above it. When there is a vehicle above it, the first sensor 5 outputs a first level signal; when there is no vehicle above it, the first sensor 5 outputs a second level signal.

[0031] The ground sensor coil 1 is buried in the middle area of ​​the road surface to sense whether there is a vehicle passing over it.

[0032] The ground sensing coil 1, the feeder and the capacitor inside the vehicle detector 2 constitute an LC oscillation circuit, and the signal output end of the LC oscillation circuit is connected to the signal input end of the vehicle detector 2; the signal output end of the trigger device 3 is connected to the signal input end of the vehicle detector 2; the signal output end of the first detector 4 is connected to the signal input end of the vehicle detector 2.

[0033] Reference Figure 2 The trigger device 3, the ground sensing coil 1, and the first detector 4 are installed on the road in this order along the vehicle's travel direction. A distance exists between the trigger device 3 and the ground sensing coil 1, keeping the trigger device 3 out of the magnetic field range of the ground sensing coil 1. A distance also exists between the first detector 4 and the ground sensing coil 1, keeping the first detector 4 out of the magnetic field range of the ground sensing coil 1.

[0034] The working principle of the vehicle detection device is:

[0035] In the initial state (ie, after the trigger device 3 has not been triggered for a period of time), the vehicle detector 2 controls the ground sensing coil 1 and the first detector 4 to sleep, thereby saving power.

[0036] When the vehicle is driving, when the wheel presses on the trigger device 3, the trigger device 3 sends a trigger signal to the vehicle detector 2. After receiving the trigger signal, the vehicle detector 2 controls the ground sensing coil 1 to start, and the LC oscillation circuit starts to output an oscillation signal with a frequency of f0 to the vehicle detector 2. When the vehicle passes through the area above the ground sensing coil 1, it causes the change of the magnetic field strength in the ground sensing coil 1, making the inductance L of the LC oscillation smaller and the oscillation frequency higher. The vehicle detector 2 begins to detect the change of the oscillation frequency of the ground sensing coil 1. When the oscillation frequency rises to f1, the vehicle detection module determines that a vehicle has passed the ground sensing coil 1. When the vehicle drives out of the magnetic field range of the ground sensing coil 1, the oscillation frequency returns to f0.

[0037] After the current vehicle passes the ground sensor coil 1, the vehicle detector 2 starts timing. If the trigger device 3 is not triggered within a certain period of time, the vehicle controller controls the ground sensor coil 1 to sleep.

[0038] When a vehicle passes over the ground sensing coil 1, the trigger device 3 is triggered again, indicating that the distance between the rear vehicle and the front vehicle is too small. The front of the rear vehicle may be within the magnetic field of the ground sensing coil 1 at the same time as the rear of the front vehicle. This may cause inaccurate detection of the number of vehicles. At this time, the vehicle detector 2 controller starts the first detector 4. The first sensor 5 in this embodiment is an infrared sensor. The probe of the infrared sensor is facing upward. When the upper part of the infrared sensor is blocked by the vehicle chassis, it outputs a high-level signal to the vehicle detector 2. When the upper part of the infrared sensor is not blocked, it outputs a low-level signal to the vehicle detector 2. The vehicle detector 2 judges how many vehicles have passed the ground sensing coil 1 by the change in the level signal output by the first sensor 5. The number of vehicles detected at this time is based on the detection result of the first detector 4, which can ensure the accuracy of the vehicle number detection.

[0039] When a vehicle subsequently passes through ground sensor coil 1 and trigger device 3 is not triggered, it indicates that there is no vehicle closely following the preceding vehicle. At this point, the following vehicle will not interfere with the detection of the preceding vehicle. Vehicle detector 2 controls first detector 4 to sleep, thus saving power. At this point, ground sensor coil 1 alone can accurately detect the number of passing vehicles, their speed, and their length.

[0040] The vehicle detection device in this embodiment also includes a second detector 6, which is embedded in the middle of the road surface and located behind the first detector 4 (i.e., when a vehicle moves forward, it will first pass through the detection area of ​​the first detector 4 and then the detection area of ​​the second detector 6). The second detector 6 includes a housing and a second sensor 7 disposed on the housing. The second sensor 7 is used to detect whether there is a vehicle above it. When a vehicle is above it, the second sensor 7 outputs a third level signal; when no vehicle is above it, the second sensor 7 outputs a fourth level signal. The signal output terminal of the second detector 6 is connected to the signal input terminal of the vehicle detector 2.

[0041] The second sensor 7 in this embodiment is also an infrared sensor, with its probe facing upward.

[0042] When the distance between the rear vehicle and the front vehicle is very close, the vehicle detector 2 controls the first detector 4 and the second detector 6 to start at the same time. When the vehicle passes over the first detector 4 and the second detector 6, the level signals output by the first detector 4 and the second detector 6 change successively. The distance between the first detector 4 and the second detector 6 and the time point when the vehicle passes the first detector 4 and the second detector 6 can be used to accurately calculate the moving speed of the vehicle. According to the moving speed of the vehicle and the time point when the front of the vehicle approaches the first detector 4 and the rear of the vehicle moves away from the first detector 4, the length of the vehicle can be accurately calculated.

[0043] Considering that the magnetic field in the environment surrounding the ground sensing coil 1 will be superimposed on the magnetic field of the ground sensing coil 1, causing the change of the magnetic field strength inside the ground sensing coil 1, and then affecting the inductance of the ground sensing coil 1, the interference may cause the oscillation frequency of the ground sensing coil 1 to be close to the frequency f1, thereby causing the vehicle detector 2 to misjudge and make the detection result inaccurate.

[0044] To avoid the above situation, refer to Figure 3 In this embodiment, a switch unit 12 is installed at one end of the ground sensor coil 1. Jumper wires 11 are connected to each turn of the ground sensor coil 1. Each jumper wire 11 is connected in parallel to an LC oscillating circuit, and a switch unit 12 is installed on each jumper wire 11. By controlling the on and off of each switch unit 12, the vehicle detector 2 can change the number of turns of the ground sensor coil 1 connected to the LC oscillating circuit.

[0045] According to the oscillation frequency calculation formula f=1 / {2π√(LC)}, when the area and material of the ground sensing coil 1 remain unchanged, the inductance L can be adjusted by changing the number of turns of the ground sensing coil 1, thereby changing the oscillation frequency of the oscillation circuit.

[0046] The vehicle detection device in this embodiment further includes a magnetic field sensor 10, which is installed within the magnetic field range of the ground sensing coil 1. Figure 2As shown, it is the best choice to install the magnetic field sensor 10 in the central area of ​​the ground sensing coil 1.

[0047] The signal output of the magnetic field sensor 10 is connected to the signal input of the vehicle detector 2. Before the vehicle detector 2 is placed on the road, the magnetic field strength of the ground sensing coil 1 with different numbers of turns is detected and calibrated. Specifically, by connecting the coils with different numbers of turns to an LC oscillator circuit, the magnetic field sensor 10 detects the magnetic field strength when no vehicle passes through the ground sensing coil 1 (i.e., the initial magnetic field strength) and the magnetic field strength when a vehicle passes through the ground sensing coil 1 (i.e., the triggered magnetic field strength, which is the average value of multiple tests). This can determine the initial and triggered magnetic field strengths of the ground sensing coil 1 with different numbers of turns, and the measured data is stored in the vehicle detector 2.

[0048] After the vehicle detection device is installed on the road and powered on and initialized, vehicle detector 2 controls magnetic field sensor 10 to begin detecting the ambient magnetic field strength in the area of ​​ground sensing coil 1. If the ambient magnetic field strength is insufficient to affect the detection results of the vehicle detection device (i.e., the ambient magnetic field strength is significantly less than the minimum triggering magnetic field of ground sensing coil 1), vehicle detector 2 controls magnetic field sensor 10 to go dormant. When trigger device 3 is triggered by a vehicle, vehicle detector 2 controls ground sensing coil 1 to begin operating, and the vehicle detection device operates in normal mode.

[0049] If the ambient magnetic field strength is strong enough to affect the vehicle detection device's detection results—that is, if the ambient magnetic field strength is very close to a set of triggering magnetic field strengths—vehicle detector 2 changes the number of turns of ground sensing coil 1 so that the triggering magnetic field of ground sensing coil 1 is significantly greater than the ambient magnetic field strength, thereby eliminating the influence of the ambient magnetic field on the detection results and ensuring detection accuracy. The vehicle detection device operates with the currently selected number of turns.

[0050] In this way, the vehicle detection device can achieve adaptive adjustment to the environment and expand its scope of application.

[0051] Reference Figure 4The trigger device 3 in this embodiment is strip-shaped and includes an upper shell 301 and a lower shell 302. The bottom edge of the upper shell 301 is bent inward to form a curling edge 303, and the top edge of the lower shell 302 is bent inward to form a curling edge 303. An annular elastic ring 306 is provided between the upper and lower curling edges 303 along the circumference of the trigger device 3. The elastic ring 306 separates the upper shell 301 from the lower shell 302, so that a vertical movable space is formed between the two. A plurality of vertical connecting bolts 305 are provided on the inner side of the elastic ring 306 along the circumference of the trigger device 3. The lower ends of the connecting bolts 305 are connected and fixed to the curling edge 303 of the lower shell 302. A through hole 304 is provided on the curling edge 303 of the upper shell 301. The upper ends of the connecting bolts 305 pass through the through hole 304 and have a bolt head on their upper ends. Such a structure allows the upper shell 301 to move up and down relative to the lower shell 302 , and the upper shell 301 and the lower shell 302 will not separate.

[0052] A trigger switch 310 is housed within the lower housing 302, while a push rod 311 is mounted within the upper housing 301, aligned with the trigger switch 310. When the wheel presses against the trigger mechanism 3 and the upper housing 301 moves downward, the end of the push rod 311 presses against the trigger switch 310, triggering it and generating the aforementioned trigger signal. During this process, the elastic ring 306 is compressed, storing energy. When the wheel leaves the trigger mechanism 3, the elastic ring 306 returns to its original shape, and its elastic force drives the upper housing 301 upward and back to its original position.

[0053] In this embodiment, the top and bottom surfaces of the elastic ring 306 are bonded to the curled edges 303 of the upper shell 301 and the lower shell 302, respectively, using waterproof adhesive. This allows the elastic ring 306 to seal the upper shell 301 and the lower shell 302, providing a waterproof and dustproof seal, preventing water and dust from entering the trigger device 3.

[0054] In this embodiment, an annular inner sealing ring 307 is disposed along the circumference of the trigger mechanism 3 between the elastic ring 306 and the connecting bolt 305. The inner sealing ring 307 is a membrane-like structure, with its top and bottom surfaces sealingly bonded to the curled edges 303 of the upper shell 301 and the lower shell 302, respectively. The inner sealing ring 307 and the elastic ring 306 form a double seal, enhancing the water and dustproof properties of the trigger mechanism 3. The membrane-like inner sealing ring 307 is stress-free and flexible, extending its service life compared to the elastic ring 306. This prevents water or dust from entering the trigger mechanism 3 due to aging and cracking of the elastic ring 306.

[0055] In this embodiment, a first magnet 308 is mounted on the bottom of the upper housing 301, and a second magnet 309 is mounted on the top of the lower housing 302. The first magnet 308 and the second magnet 309 repel each other. The repulsive force between the first magnet 308 and the second magnet 309 provides additional support, compensating for the loss of elastic force of the elastic ring 306 due to aging, and ensuring that the upper housing 301 can be smoothly reset.

[0056] Reference Figure 5 The vehicle detector 2 in this embodiment includes a main control module, and also includes a dip switch, a wireless communication module, a storage module, an oscillation circuit, a storage module and a power management module. The dip switch is connected to the I / O end of the main control module. The dip switch is set on the housing of the vehicle detector 2 for manual operation by the user. It is used to send a level signal to the main control module by operating the dip switch. After receiving the dip signal, the main control module controls the corresponding switch unit 12 to act, thereby adjusting the number of turns of the ground sensing coil 1, so that the user can manually adjust the sensitivity of the vehicle detection device; the wireless communication module is connected to the communication serial port of the main control module. The wireless communication module is used for wireless communication and data transmission between the main control vehicle detector 2 and the host computer. The use of wireless communication can reduce the wiring of the system and simplify the workload; the storage module is connected to the data read and write end of the main control module. The storage module is used to store calibrated magnetic field strength data and temporarily store detection result data; the oscillation The signal output end of the circuit is connected to the sampling signal input end of the main control module, the ground sensing coil 1 is connected to the oscillation circuit through the switch unit 12, the signal output end of the magnetic field sensor 10 is connected to the sampling signal input end of the main control module, the trigger switch 310 is connected to the I / O end of the main control module, and the signal output ends of the first sensor 5 and the second sensor 7 are both connected to the sampling signal input end of the main control module; the output end of the power management module is connected to the main control module and each module and component, and is used to power the entire vehicle detection device. The control signal output end of the main control module is connected to the control end of the power management module, and is used to control the various power signals output by the power management module. By controlling the various power signals, the working status of the ground sensing coil 1 and each sensor is controlled.

[0057] Example 2:

[0058] A wireless ground sensing vehicle detection method comprises the following steps:

[0059] S1. A trigger device is provided in front of the ground sensing coil, and a first detector is provided behind the ground sensing coil;

[0060] S2. When the trigger device is triggered by a vehicle, the ground sensing coil is activated to detect the vehicle; when a vehicle passes the ground sensing coil, the trigger device is triggered again, and the first vehicle detector is activated to detect the number of vehicles through the first detector;

[0061] S3. When the trigger device is not triggered again for a period of time, the ground sensing coil is controlled to stop working.

[0062] In this embodiment, in step S1, a second detector is also provided behind the first detector; in step S2, when a vehicle passes through the ground sensing coil, the trigger device is triggered again, and the first detector and the second detector are started, and the number of vehicles is detected by the first detector, and the moving speed and length of the vehicle are calculated based on the distance between the first detector and the second detector and the time point when the vehicle passes through the first detector and the second detector.

[0063] In this embodiment, a trigger device is set in front of the ground sensing coil and a detector is set behind the ground sensing coil. The magnetic field strength of the environment around the ground sensing coil is also detected, and the detection result is compared with the trigger magnetic field strength of different turns of the ground sensing coil calibrated in advance. When the two are close, the number of turns of the ground sensing coil is changed, and the trigger magnetic field strength of the ground sensing coil is switched to a higher level.

[0064] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A wireless ground-sensing vehicle detection device, comprising a vehicle detector and a ground-sensing coil, characterized in that: The vehicle further comprises a trigger device, the trigger device being installed at an edge area of ​​the road surface and configured to sense pressure from the wheels and be triggered when receiving the pressure from the wheels, and to send a trigger signal when the trigger device is triggered; a first detector, the first detector being buried in a middle area of ​​a road surface, the first detector comprising a housing and a first sensor disposed on the housing, the first sensor being configured to detect whether there is a vehicle above the first detector, and outputting a first level signal when a vehicle is above the first detector; When there is no vehicle above it, the first sensor outputs a second level signal; The ground sensing coil is buried in the middle area of ​​the road surface and is used to sense whether a vehicle passes over it. The ground sensing coil, the feeder, and the capacitor inside the vehicle detector form an LC oscillation circuit, which is connected to and controlled by the vehicle detector; the trigger device is connected to and controlled by the vehicle detector; and the first detector is connected to and controlled by the vehicle detector. The trigger device, the ground sensing coil, and the first detector are sequentially installed on the road along the direction of travel of the vehicle. A distance exists between the trigger device and the ground sensing coil, such that the trigger device is away from the magnetic field range of the ground sensing coil. A distance also exists between the first detector and the ground sensing coil, such that the first detector is away from the magnetic field range of the ground sensing coil. Each coil of the ground sensing coil is connected to a jumper wire, each jumper wire is connected in parallel to an LC oscillation circuit, and each jumper wire is provided with a switch unit, and the switch unit is connected to and controlled by a vehicle detector. The vehicle detection device further includes a magnetic field sensor, which is installed within the magnetic field range of the ground sensing coil, and the magnetic field sensor is connected to and controlled by the vehicle detector. The signal output end of the magnetic field sensor is connected to the signal input end of the vehicle detector. Before the vehicle detector is placed on the road, the magnetic field strength of the ground sensing coil with different numbers of turns is detected and calibrated; After the vehicle detection device is installed on the road, the vehicle detector controls the magnetic field sensor to start detecting the ambient magnetic field strength in the ground sensing coil area. If the ambient magnetic field strength is not strong enough to affect the detection results of the vehicle detection device, that is, the ambient magnetic field strength is much smaller than the minimum triggering magnetic field of the ground sensing coil, the vehicle detector controls the magnetic field sensor to sleep. When the trigger device is triggered by a vehicle, the vehicle detector controls the ground sensing coil to start working, and the vehicle detection device works in normal mode; If the ambient magnetic field strength is sufficient to affect the detection results of the vehicle detection device, that is, when the ambient magnetic field strength is very close to the trigger magnetic field strength corresponding to a certain number of turns, the vehicle detector changes the number of turns of the ground sensing coil so that the trigger magnetic field of the ground sensing coil is greater than the ambient magnetic field strength, and the vehicle detection device operates with the currently selected number of turns.

2. The wireless ground sensing vehicle detection device according to claim 1, characterized in that: Also includes The second detector is connected to and controlled by the vehicle detector. The second detector is used to be buried in the middle area of ​​the road surface, and the second detector is located behind the first detector. The second detector includes a shell and a second sensor arranged on the shell. The second sensor is used to detect whether there is a vehicle above it. When there is a vehicle above it, the second sensor outputs a third level signal; when there is no vehicle above it, the second sensor outputs a fourth level signal.

3. The wireless ground sensing vehicle detection device according to claim 2, characterized in that: The first sensor and the second sensor are infrared sensors or distance sensors.

4. The wireless ground sensing vehicle detection device according to claim 1, characterized in that: The trigger device is strip-shaped, and includes an upper shell and a lower shell. The bottom edge of the upper shell is bent inward to form a curling edge, and the top edge of the lower shell is bent inward to form a curling edge. An annular elastic ring is arranged between the upper and lower curling edges along the circumference of the trigger device. The top and bottom surfaces of the elastic ring are respectively bonded and fixed to the curling edge of the upper shell and the curling edge of the lower shell by waterproof glue. The elastic ring separates the upper shell and the lower shell, so that a vertical activity space is formed between the two. A plurality of vertical connecting bolts are arranged on the inner side of the elastic ring along the circumference of the trigger device, and the lower end of the connecting bolt is connected and fixed to the curling edge of the lower shell. A through hole is provided on the curling edge of the upper shell, and the upper end of the connecting bolt passes through the through hole and the upper end of the connecting bolt has a bolt head. A trigger switch is installed inside the lower shell, and a push rod is installed in the upper shell, and the push rod is aligned with the trigger switch.

5. The wireless ground sensing vehicle detection device according to claim 4, characterized in that: An annular inner sealing ring is arranged between the elastic ring and the connecting bolt along the circumference of the trigger device. The inner sealing ring is a membrane structure, and its top and bottom surfaces are sealed and bonded to the curled edges of the upper shell and the lower shell respectively. A first magnet is installed at the bottom of the upper shell, and a second magnet is installed at the top of the lower shell. The first magnet and the second magnet repel each other.

6. The wireless ground sensing vehicle detection device according to claim 1, characterized in that: The vehicle detector includes a main control module, and also includes a dial switch, a wireless communication module, a storage module, an oscillation circuit, a storage module and a power management module connected to the main control module.

7. A wireless ground sensing vehicle detection method implemented by the wireless ground sensing vehicle detection device according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. A trigger device is provided in front of the ground sensing coil, and a first detector is provided behind the ground sensing coil; S2. When the trigger device is triggered by a vehicle, the ground sensing coil is activated to detect the vehicle; when a vehicle passes the ground sensing coil, the trigger device is triggered again, and the first vehicle detector is activated to detect the number of vehicles through the first detector; S3. When the trigger device is not triggered again for a period of time, the ground sensing coil is controlled to stop working; The method also includes the following steps: setting a trigger device in front of the ground sensing coil and setting a detector behind the ground sensing coil; detecting the magnetic field strength of the environment around the ground sensing coil; and comparing the detection result with the trigger magnetic field strength corresponding to different numbers of turns of the ground sensing coil calibrated in advance; when the two are close, changing the number of turns of the ground sensing coil and switching the trigger magnetic field strength of the ground sensing coil to a higher level.

8. The wireless ground sensing vehicle detection method according to claim 7 is characterized in that: In step S1, a second detector is also set behind the first detector; in step S2, when a vehicle passes the ground sensing coil, the trigger device is triggered again, and the first detector and the second detector are started. The number of vehicles is detected by the first detector, and the moving speed and length of the vehicle are calculated based on the distance between the first detector and the second detector and the time point when the vehicle passes the first detector and the second detector.

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