Vehicle wading induction system based on laser radar sampling and detection method

Abstract

The invention provides a vehicle wading induction system and detection method based on laser radar sampling, and belongs to the technical field of vehicle electronics, and the system comprises a first laser radar probe and a second laser radar probe which are installed at the outer side of a vehicle body; a data processing algorithm and a communication interface are integrated in the vehicle body domain controller, and the vehicle body domain controller is used for receiving water surface distance data measured by the first laser radar probe and the second laser radar probe; meanwhile, related vehicle body posture information transmitted by the chassis domain control input unit is received; calculating water depth by combining a data processing algorithm to obtain a water depth signal; according to the intelligent system, the problem that the distance measuring capability and the ambient light interference resistance of the whole SPAD chip module are weak is solved, the application requirements of wading radar are met, the effect is better than that of a traditional ultrasonic sensor detection technology, and the intelligent system for high-precision water depth detection is achieved through the low-cost laser radar module.

Description

Technical Field

[0001] The present invention belongs to the field of vehicle electronics, and particularly relates to a vehicle wading induction system and detection method based on lidar sampling. Background Art

[0002] With the accelerating urbanization process year by year, vehicle travel has become more and more popular in people's production and life; when encountering heavy rain, vehicles are prone to wading and getting into danger when driving on waterlogged roads, especially on the sloping roads under bridges; because it is impossible for vehicle owners to make effective and accurate judgments when visually estimating the water depth; and existing vehicles cannot achieve a completely sealed state during production and manufacturing, so wading into dangerous areas will cause water to enter the cab and engine compartment, resulting in serious consequences; at least, it will cause the vehicle to stall, resulting in subsequent property losses; at worst, it will cost lives.

[0003] In order to avoid the occurrence of the above-mentioned dangers, various vehicle manufacturers and related R & D departments have successively developed auxiliary in-vehicle systems for detecting vehicle wading, such as:

[0004] ① Patent publication number: CN109282872A, invention name: Vehicle and wading detection system and method therefor;

[0005] This invention designs a wading detection system, including: a water level sensor, which is arranged on the vehicle and has a first preset distance from the horizontal road surface where the vehicle is located. The water level sensor is used to detect the distance between itself and the water surface of the accumulated water when the vehicle wades to obtain a distance detection value; an inclination angle acquisition module, which is used to respectively acquire the first inclination angle of the vehicle body in the first direction and the second inclination angle in the second direction; a control module, which is used to calculate the water accumulation height at the current position of the vehicle according to the first preset distance, the distance detection value, the first inclination angle and the second inclination angle.

[0006] ② Patent publication number: CN115900879A, invention name: Water depth detection device, vehicle and vehicle wading depth detection method;

[0007] This invention designs a water depth detection device, including: a sensor assembly, the sensor assembly includes a differential pressure sensor and a wading pipeline. The first end of the differential pressure sensor is communicated with the first end of the wading pipeline, the second end of the differential pressure sensor is communicated with the external air and forms an air interface, the second end of the wading pipeline is a wading interface, the plane where the wading interface of the wading pipeline is located is higher than the plane where the air interface is located, and the differential pressure sensor is used to detect the pressure difference between the pressure in the wading pipeline and the external air pressure; a first calculation module, which is used to calculate the wading depth according to the pressure difference, the density of water and the vertical distance from the wading interface of the wading pipeline to the ground.

[0008] Through the architecture of the sensor fusion component, the above technical solution realizes wading warning by combining a camera, a pressure sensor or a water level sensor. This method has a high implementation cost, relies heavily on complex algorithms, has a slow reaction speed, and is not conducive to later maintenance and application promotion.

[0009] ③ A method for detecting wading depth of a vehicle wading radar. Through the architecture design of the wading radar, it relies on an ultrasonic sensor to complete wading detection, and estimates the water depth by transmitting ultrasonic waves and receiving reflected signals; the echo calculation it adopts includes: a primary water surface echo and a primary bottom ground echo;

[0010] The sampling of the echo formulas of the above two parameters not only makes the calculation complex and energy-consuming, but also easily causes sampling errors in any one echo data, which will lead to inaccurate calculation of the wading depth and increase the uncertainty of judgment; and usually because the impedance difference between air and underwater sound is very large, most of the sound waves will be reflected by the water surface, and only a small amount of energy enters the water; therefore, this method is not sufficient to allow enough sound waves to reach the bottom and be reflected back to be detected by the receiver, and there are defects in the practicability of this solution.

[0011] ④ The radar probes used in the existing wading induction systems on automobiles are all ultrasonic radars because of their low cost and can meet the basic requirements; traditional lidar is difficult to meet the cost requirements of the wading induction system because of its high cost;

[0012] Some chip companies such as ST and AMS have developed a chip-level tof sensor that integrates multiple functional modules such as MCU, laser driver, SPAD photosensitive array, SPAD signal processing (TDC & histogram), ranging data processing, clock, power management, and logic control into a SPAD ASIC chip, and packages it with a VCSEL bare chip into a chip module, which has the characteristics of extremely small size, extremely low cost, and low power consumption.

[0013] However, the requirements for ranging and anti-environmental light of such consumer electronics applications are not very high. Therefore, the ranging ability and anti-environmental light ability requirements of the chip-level tof sensor under the limitations of size, cost, and power consumption are weak. It is usually applied to the auxiliary focusing function in indoor or low-light conditions. The maximum ranging in low-light environments is about 4m, and the maximum ranging in strong-light environments is about 0.3m, and it is difficult to be applied to a wider range of scenarios. Summary of the Invention

[0014] To solve the above technical problems, the present invention provides a vehicle wading sensing system and detection method based on lidar sampling. With a scientific architecture and combined with an original and efficient algorithm formula design, it samples environmental data based on the high anti-interference performance of lidar, greatly improving the water depth detection accuracy, and can obtain the water depth at the front end of the vehicle, so as to predict in advance whether the vehicle can pass; at the same time, it uses a low-cost transceiver integrated lidar chip to reduce the cost of the lidar system; through optical design, the laser spot is shaped into an appropriate divergence angle to eliminate the influence of vehicle body tilt and water surface fluctuation on ranging.

[0015] In a first aspect, a vehicle wading sensing system based on lidar sampling includes:

[0016] A first lidar probe and a second lidar probe installed on the outer side of the vehicle body;

[0017] A chassis domain control input unit, provided with a vehicle inclination sensor (IMU), for transmitting relevant vehicle body attitude information to the vehicle body domain controller;

[0018] A vehicle body domain controller: internally integrated with a data processing algorithm and a communication interface, for:

[0019] Receiving the water surface distance data measured by the first lidar probe and the second lidar probe; at the same time, receiving the relevant vehicle body attitude information transmitted by the chassis domain control input unit; combining the data processing algorithm to calculate the water depth and obtaining a water depth signal;

[0020] An instrument: for receiving the water depth signal and displaying or alarming the water depth data.

[0021] As an example, the first lidar probe is installed under the left rearview mirror; the second lidar probe is installed under the right rearview mirror; the direction of its central optical axis is vertically downward when the vehicle is horizontally placed.

[0022] As an example, the first lidar probe includes: a PCBA, a mirror base, a receiving lens, a transmitting lens, and a housing;

[0023] The PCBA includes: a PCB and chips, connectors, an MCU and peripheral circuits thereon. Among them: the chip uses a SPAD SoC chip, which integrates multiple functional modules such as VCSEL drive, SPAD photosensitive array, SPAD signal processing (TDC & histogram), ranging data processing, clock, power management, and logic control. The VCSEL drive is driven by the SPAD SoC chip to emit light;

[0024] The MCU is used to control and configure the SPAD SoC chip, read the ranging data of the SPAD SoC chip, process the data, and store relevant calibration parameters;

[0025] The connector is used for communicating and supplying power with the outside;

[0026] The transmitting lens and the receiving lens are respectively arranged above the light passing holes of the laser and the detector of the SPAD SoC chip through the lens holder;

[0027] The housing is required to meet the automotive protection level, and the material of the light-transmitting part is an infrared highly transparent material.

[0028] As an example, the infrared highly transparent material refers to: infrared PC, which is used to project infrared laser.

[0029] As an example, the transmitting lens is used to shape the emission spot of the laser into an elliptical shape; the emission spot faces the ground, and it is ensured that for the elliptical emission spot, the long axis direction of the ellipse is consistent with the vehicle traveling direction.

[0030] As an example, for the elliptical emission spot, the divergence angle in the long axis direction of the ellipse is set to 30°. This can ensure that when the vehicle tilts forward and backward or the water surface fluctuates, there is still a strong echo signal on the water surface; (the 30° divergence angle is a reference value, and it can be adjusted and determined according to the tilt angle that the vehicle can reach during actual use);

[0031] The divergence angle in the short axis direction of the ellipse is set to 15°, which ensures that when the vehicle tilts left and right or the water surface fluctuates, there is still a strong echo signal on the water surface that can be detected by the detector. (This angle is a reference value and is actually determined according to the tilt angle that the vehicle may reach).

[0032] As an example, the receiving lens is used to shape the receiving field of view into an elliptical shape to match the emission spot.

[0033] As an example, the first lidar probe is used as the main radar, and the second lidar probe is used as the slave radar, and their structures are the same.

[0034] As an example, the relevant vehicle body attitude information includes: vehicle body inclination angle information, wheel speed signal, and chassis height parameter.

[0035] As an example, the instrument is provided with a touch button structure for turning on or off the wading sensing function.

[0036] As an example, the instrument is one of: mechanical pointer type, electronic digital display type, or liquid crystal touch type.

[0037] In a second aspect, a vehicle wading detection method based on lidar sampling includes:

[0038] Step 1: Dual radar ranging fusion;

[0039] The first lidar probe and the second lidar probe synchronously transmit radar beam signals, and respectively measure the distance values from the water surface to the first lidar probe and the second lidar probe;

[0040] Step 2: Design of data processing algorithm;

[0041] Receive the water surface distance data measured by the first lidar probe and the second lidar probe; at the same time, receive the relevant vehicle body attitude information transmitted by the chassis domain control input unit; calculate the water depth in combination with the data processing algorithm to obtain a water depth signal;

[0042] The data processing algorithm is implemented through the water depth calculation model formula 1, and the formula 1 is designed as follows:

[0043] h = [H - max{d1, d2}] / cos(α) + L*α; Formula 1

[0044] Where: h is the actual water depth at the frontmost position of the vehicle; H: the height from the lower edge of the vehicle's rearview mirror to the ground (pre-stored vehicle body parameter, which can be obtained from the vehicle drawing, and the height from the lower edges of the left and right rearview mirrors of almost all vehicles to the ground is equal); d1: the ranging value of the first lidar probe (i.e., the distance from the first lidar probe along the central optical axis to the water surface); d2: the ranging value of the second lidar probe (i.e., the distance from the second lidar probe along the central optical axis to the water surface); max{d1, d2}: that is, the logical judgment operation of d1 and d2, taking the maximum value of the two; α: the pitch angle of the vehicle (provided by the tilt sensor); L is the distance in the vehicle length direction from the center position of the rearview mirror lidar probe to the frontmost end of the vehicle's front bumper (pre-stored vehicle body parameter, which can be obtained from the vehicle drawing).

[0045] Step 3: Transmit the obtained actual water depth signal to the instrument display in real time to remind the driver to avoid danger in time.

[0046] In a third aspect, the present application shows a non-transitory computer-readable storage medium, which can implement a vehicle wading detection method based on lidar sampling when the instructions in the storage medium are executed by a processor.

[0047] In a fourth aspect, the present application shows a computer program product, which can execute a vehicle wading detection method based on lidar sampling when the instructions in the computer program product are executed by a processor.

[0048] Advantages of the present invention:

[0049] This application solves the problems of weak ranging ability and weak anti-environmental light interference ability of the TOF SPAD chip module, enabling it to meet the application requirements of the water-wading radar, and solves the problems of high cost and large size of the TOF sensor using a discrete device solution; an intelligent system with high-precision water depth detection and anti-environmental interference is realized through a low-cost lidar module.

[0050] The TOF SPAD chip module applied to consumer electronics is matched with a lens to increase the light transmission aperture of the module, improve the light energy collection efficiency and light energy utilization efficiency; reduce the divergence angle of the transceiver field of view, reduce the input of ambient light, and improve the overall optical signal-to-noise ratio, achieving the effect of improved ranging ability, and meeting the application of the water-wading radar at extremely low cost, size and power consumption.

[0051] At the same time, considering the specific application scenario of the water-wading radar, the vehicle body will tilt forward and backward and left and right on a bumpy road surface, and the water surface will also fluctuate. If the field of view angle is too small, the echo signal is easily reflected by the water surface outside the receiving field of view, resulting in discontinuous ranging loss; the present invention comprehensively considers and designs a reasonable transceiver field of view angle and optical lens to meet the requirements of both ranging ability and ranging continuity; and through algorithm formulas, calculates the water depth at the front end of the vehicle, so as to predict in advance whether the vehicle can pass. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 It is a schematic diagram of the overall structure of a vehicle water-wading sensing system based on lidar sampling according to the present invention.

[0053] Figure 2 It is a schematic diagram of the emission light spots of the first lidar probe and the second lidar probe of a vehicle water-wading sensing system based on lidar sampling according to the present invention.

[0054] Figure 3 It is a schematic diagram of the structure of the first lidar probe of a vehicle water-wading sensing system based on lidar sampling according to the present invention.

[0055] Figure 4 It is a schematic diagram of the water-wading detection principle of a vehicle water-wading detection method based on lidar sampling according to the present invention.

[0056] Figure 5 It is a second schematic diagram of the structure of the first lidar probe of a vehicle water-wading sensing system based on lidar sampling according to the present invention. (Embodiment 1) DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application. Refer to Figures 1 to 5 as shown

[0058] Refer to Figure 1 as shown, a vehicle wading induction system based on lidar sampling includes:

[0059] A first lidar probe 101 and a second lidar probe 102 installed on the outside of the vehicle body;

[0060] A chassis domain control input unit 103, provided with a vehicle inclination sensor (IMU), for transmitting relevant vehicle body attitude information to the vehicle body domain controller 104;

[0061] The vehicle body domain controller 104: internally integrated with data processing algorithms and communication interfaces, for:

[0062] Receiving the water surface distance data measured by the first lidar probe 101 and the second lidar probe 102; at the same time, receiving the relevant vehicle body attitude information transmitted by the chassis domain control input unit 103; calculating the water depth in combination with the data processing algorithm to obtain a water depth signal;

[0063] An instrument 105: for receiving the water depth signal and displaying or alarming the water depth data.

[0064] As an example, the first lidar probe 101 is installed under the left rearview mirror; the second lidar probe 102 is installed under the right rearview mirror.

[0065] Refer to Figure 3 as shown, the first lidar probe 101 includes: a PCBA, a mirror base 111, a receiving lens 108, a transmitting lens 109, and a housing 110;

[0066] The PCBA includes: a PCB 106 and a chip 107, a connector 112, and an MCU and peripheral circuits 113 thereon. Among them: the chip 107 uses a SPAD SoC chip, which integrates multiple functional modules such as VCSEL drive, SPAD photosensitive array, SPAD signal processing (TDC & histogram), ranging data processing, clock, power management, and logic control. The VCSEL drive is driven by the SPAD SoC chip to emit light;

[0067] The MCU is used to control and configure the SPAD SoC chip, read the ranging data of the SPAD SoC chip, process the data, and store relevant calibration parameters;

[0068] The connector 112 is used for communication and power supply with the outside;

[0069] The transmitting lens 109 and the receiving lens 108 are respectively arranged above the light passing holes of the laser and the detector of the chip through the lens holder 111 at appropriate positions, so that the fields of view of transmission and reception reach the designed elliptical shape;

[0070] The housing 110 is required to meet the automotive protection level, and the material of the light-transmitting part is an infrared highly transparent material.

[0071] As an example, the infrared highly transparent material refers to: infrared PC, which is used to transmit infrared laser.

[0072] Refer to Figure 2 As shown, the transmitting lens 109 is used to shape the emission spot of the laser into an elliptical shape; the emission spot faces the ground, and it is ensured that for the elliptical emission spot, the long axis direction of the ellipse is consistent with the vehicle traveling direction.

[0073] As an example, for the elliptical emission spot, the divergence angle in the long axis direction of the ellipse is set to 30°, which can ensure that when the vehicle tilts forward and backward or the water surface fluctuates, there is still a strong echo signal on the water surface; (the 30° divergence angle is a reference value, and it can be adjusted and determined according to the tilt angle that the vehicle can reach during actual use);

[0074] The divergence angle in the short axis direction of the ellipse is set to 15°, which ensures that when the vehicle tilts left and right or the water surface fluctuates, there is still a strong echo signal on the water surface that can be detected by the detector. (This angle is a reference value and is actually determined according to the tilt angle that the vehicle may reach).

[0075] As an example, the receiving lens 108 is used to shape the receiving field of view into an elliptical shape to match the emission spot.

[0076] The concept of the receiving field of view corresponds to that of the transmitting field of view. Just that the transmitting field of view is visible if it hits a target such as the ground, which is an elliptical spot; the receiving field of view means that the light signals within this field of view can all return to the detector. This light signal that returns to the detector is called the echo signal. Usually, the transmitting field of view and the receiving field of view of a lidar are designed to be the same, so that the echo of the emission spot can completely return to the receiving field of view. If the receiving field of view is set too large, stray light will also return and the noise will be strong. If it is set too small, only part of the light energy of the emission spot can return and the signal will be weak. So usually the transmitting field of view and the receiving field of view are set to be the same.

[0077] As an example, the first lidar probe 101 serves as the main radar, and the second lidar probe 102 serves as the slave radar, and their structures are the same.

[0078] As an example, the relevant vehicle body attitude information includes: vehicle body inclination angle information, wheel speed signal, and chassis height parameter.

[0079] As an example, the instrument 105 is provided with a touch button structure for turning on or off the wading sensing function.

[0080] As an example, the instrument 105 is one of the following: mechanical pointer type, electronic digital display type, or liquid crystal touch type.

[0081] Refer to Figure 4 As shown, a vehicle wading detection method based on lidar sampling includes:

[0082] Step 1: Dual-radar ranging fusion;

[0083] The first lidar probe and the second lidar probe synchronously emit radar beam signals, and respectively measure the distance values from the water surface to the first lidar probe and the second lidar probe;

[0084] Step 2: Design of data processing algorithm;

[0085] Receive the water surface distance data measured by the first lidar probe and the second lidar probe; at the same time, receive the relevant vehicle body attitude information transmitted by the chassis domain control input unit; calculate the water depth in combination with the data processing algorithm to obtain a water depth signal;

[0086] The data processing algorithm is implemented through the water depth calculation model formula 1, and the formula 1 is designed as follows:

[0087] h = [H - max{d1, d2}] / cos(α) + L * α; Formula 1

[0088] Where: h is the actual water depth at the frontmost position of the vehicle; H: the height from the lower edge of the vehicle rearview mirror to the ground (pre-stored vehicle body parameter, which can be obtained from the vehicle drawing, and the height from the lower edges of the left and right rearview mirrors of almost all vehicles to the ground is equal); d1: the ranging value of the first lidar probe; d2: the ranging value of the second lidar probe; max{d1, d2}: that is, the logical decision operation of d1 and d2, taking the maximum value of the two, that is Figure 4 the d shown; α: the pitch angle of the vehicle (provided by the inclination sensor); L is the distance in the vehicle length direction from the center position of the rearview mirror lidar probe to the frontmost end of the vehicle front bumper (pre-stored vehicle body parameter, which can be obtained from the vehicle drawing).

[0089] Step 3: Transmit the obtained actual water depth signal to the instrument for real-time display to remind the driver to take timely evasive action.

[0090] In a third aspect, the present application discloses a non-transitory computer-readable storage medium, which, when the instructions in the storage medium are executed by a processor, can implement a vehicle wading detection method based on lidar sampling.

[0091] In a fourth aspect, the present application discloses a computer program product, which, when the instructions in the computer program product are executed by a processor, can execute a vehicle wading detection method based on lidar sampling.

[0092] Example 1: Refer to Figure 5 as shown;

[0093] An alternative solution is that the first lidar probe and the second lidar probe can also be designed as follows:

[0094] Use a light shield 201 to limit and crop the original field of view angle of the chip within the required angle range;

[0095] This solution has a lower cost than the previous solution, but it can only reduce the original field of view angle of the chip, and cannot, like the previous solution, not only reduce the field of view angle (by narrowing the beam with a convex lens), but also increase the field of view angle (by diffusing the beam with a concave lens).

[0096] Example 2:

[0097] By comparing the usage effects of the existing ultrasonic radar wading warning with that of the lidar of the present invention, an effect comparison was carried out, as shown in Table 1:

[0098]

[0099] Table 1

[0100] It can be seen from the comparison that the present invention has high precision and strong environmental adaptability. The lidar has a high ranging accuracy, and the error in different temperatures, air pressures, wind speeds, and turbid water bodies is less than ±2 cm (compared with ±10 cm of the ultrasonic wave); the present invention has a low cost and a small volume. Compared with the existing ultrasonic radar, the cost is reduced by 20% and the volume is reduced by 30%.

[0101] It should be noted that for the method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present application is not limited by the described action sequence, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all optional embodiments, and the actions involved are not necessarily essential to the present application.

[0102] The embodiments of the present application also provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements each process of the above method embodiments and can achieve the same technical effects. To avoid repetition, it will not be elaborated here. Among them, the computer-readable storage medium, such as a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disc, etc.

[0103] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated here.

[0104] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there may be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be electrical, mechanical, or other forms.

[0105] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or they can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0106] In addition, in each embodiment of the present application, the functional units can be integrated in one processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit.

[0107] When the above-mentioned functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art or a part of this technical solution can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of this application. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical discs that can store program codes.

[0108] The foregoing are only the preferred embodiments of the present invention. It should be understood that the description of the above embodiments is only used to help understand the method and its core idea of the present invention, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, etc. made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A vehicle wading sensing system based on laser radar sampling, characterized in that: include: A first laser radar probe and a second laser radar probe installed on the outside of the vehicle body; The chassis domain control input unit is provided with a vehicle tilt sensor for transmitting relevant vehicle body posture information to the vehicle body domain controller; Body domain controller: It integrates data processing algorithms and communication interfaces for: Receive the water surface distance data measured by the first laser radar probe and the second laser radar probe; simultaneously receive the relevant vehicle body posture information transmitted by the chassis domain control input unit; calculate the water depth in combination with the data processing algorithm to obtain a water depth signal; Instrument: used to receive the water depth signal and display or alarm the water depth data.

2. The vehicle wading sensing system based on laser radar sampling according to claim 1 is characterized in that: The first laser radar probe is installed below the left rearview mirror; the second laser radar probe is installed below the right rearview mirror.

3. The vehicle wading sensing system based on laser radar sampling according to claim 1 is characterized in that: The first laser radar probe includes: PCBA, a lens holder, a receiving lens, a transmitting lens and a housing; The PCBA includes: a PCB and a chip, a connector, an MCU and peripheral circuits thereon, wherein: the chip adopts a SPADSoC chip, which integrates VCSEL drive, SPAD photosensitive array, SPAD signal processing, ranging data processing, clock, power management, and logic control functional modules, and the VCSEL drive is driven by the SPAD SoC chip to emit light; The MCU is used to control and configure the SPAD SoC chip, read the ranging data of the SPAD SoC chip, process the data, and store relevant calibration parameters; The connector is used for communicating with the outside and supplying power; The transmitting lens and the receiving lens are respectively arranged above the laser and the detector light holes of the SPAD SoC chip through the lens holder; The housing is required to meet the automotive protection level, and the light-transmitting part is made of a material with high infrared transmittance.

4. The vehicle wading sensing system based on laser radar sampling according to claim 3 is characterized in that: The emission lens is used to shape the emission spot of the laser into an elliptical shape; The emission spot is directed toward the ground and the emission spot is ensured to be elliptical in shape, with the major axis of the ellipse consistent with the direction of vehicle travel; The elliptical emission spot has a divergence angle of 30° in the direction of the major axis of the ellipse and a divergence angle of 15° in the direction of the minor axis of the ellipse. This ensures that when the vehicle tilts forward or backward or the water surface fluctuates, there is still a strong echo signal on the water surface.

5. The vehicle wading sensing system based on laser radar sampling according to claim 3 is characterized in that: The receiving lens is used to shape the receiving field of view into an elliptical shape to match the emission light spot.

6. The vehicle wading sensing system based on laser radar sampling according to claim 1 is characterized in that: The first laser radar probe is used as a main radar, and the second laser radar probe is used as a slave radar, and the two have the same structure.

7. The vehicle wading sensing system based on radar sampling according to claim 1, characterized in that: The relevant vehicle body posture information includes: vehicle body inclination information, wheel speed signal and chassis height parameter.

8. The vehicle wading sensing system based on laser radar sampling according to claim 1 is characterized in that: The instrument is provided with a touch button structure for turning on or off the wading sensing function.

9. The vehicle wading sensing system based on laser radar sampling according to claim 1, characterized in that: The instrument is one of a mechanical pointer type, an electronic digital display type or a liquid crystal touch type.

10. A vehicle wading detection method based on laser radar sampling, characterized in that: include: Step 1: Dual radar ranging fusion; The first laser radar probe and the second laser radar probe synchronously transmit radar beam signals to measure the distance values ​​from the water surface to the first laser radar probe and the second laser radar probe respectively; Step 2: Design of data processing algorithm; The body domain controller receives the water surface distance data measured by the first laser radar probe and the second laser radar probe; at the same time, receives the relevant body posture information transmitted by the chassis domain control input unit; calculates the water depth in combination with the data processing algorithm to obtain a water depth signal; The data processing algorithm is implemented by the water depth calculation model formula 1, which is designed as follows: h=[H-max{d1, d2}] / cos(α)+ L*α; Formula 1 Among them: h is the actual water depth at the front end of the vehicle; H: the height from the lower edge of the vehicle rearview mirror to the ground; d1: the distance value measured by the first laser radar probe; d2: the distance value measured by the second laser radar probe; max{d1, d2}: the logical judgment operation d1 and d2, taking the maximum value of the two; α: the pitch angle of the vehicle; L is the distance from the center of the rearview mirror laser radar probe to the front end of the vehicle in the vehicle length direction; Step 3: The actual water depth signal obtained is transmitted to the instrument display in real time to remind the driver to avoid danger in time.

Images