A wind speed monitoring method and system based on reversing radar system

Abstract

The present invention discloses a wind speed monitoring method based on a reversing radar system, comprising the following steps: adding two reversing radars at a certain interval in the middle of the front end and the middle of the rear end of the vehicle, and setting a reflector above the radar; detecting the vehicle speed, and when the vehicle speed exceeds the preset speed, starting the wind speed monitoring; the radar controller controls the radars added at the front and rear ends to mutually send and receive signals in an orderly manner to different radars located at the same end through the reflector, and analyzes the received radar echo signals through the radar controller; performing calculation and analysis of the wind direction and wind speed in the horizontal direction; synthesizing the wind speed and wind direction according to the calculation and analysis to generate a wind speed signal, and sending it to the vehicle controller. The present invention utilizes the existing radar system of the original vehicle, assists the echo surface layout design during the vehicle body design, completes the real-time monitoring of the wind speed, and provides specific wind speed signal support for other vehicle systems without adding additional configuration.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle environment perception and detection, and in particular relates to a wind speed monitoring method and system based on a reversing radar system. Background Art

[0002] At present, more and more smart cars require real-time wind speed monitoring systems, and they have higher requirements for the real-time performance and accuracy of wind speed monitoring. For example, when the ADAS system or intelligent driving system performs lateral control of the vehicle, it is necessary to make necessary safety constraints on the cornering request based on the implemented wind speed; systems such as TJA need to control the vehicle speed within a reasonable range when cornering based on the wind speed; the ESC system needs to implement different traction control strategies in the event of partial locking or slipping of the vehicle based on the wind speed control, and the reversing radar itself needs to correct the measurement error based on the wind speed parameters.

[0003] The wind speed measurement systems available now are mainly divided into aviation-grade pitot tubes, also called pitot tubes. When the aircraft flies forward, the airflow rushes into the pitot tube, and the sensor at the end of the tube will feel the impact of the airflow, that is, the dynamic pressure. The faster the aircraft flies, the greater the dynamic pressure. If you compare the static pressure when the air is still and the dynamic pressure, you can know how fast the air rushes in, that is, how fast the aircraft flies. The wind speed is determined by comparing the size of the two pressure differences.

[0004] Existing meteorological wind speed detectors are generally based on a simple blade principle, measuring wind speed by calculating the rotational speed of the blades through the blade linkage guide system.

[0005] However, these two very mature wind speed measuring instruments cannot be applied to automobiles; and in today's automobile market where competition is huge and costs need to be reduced, designing a special wind speed sensor for automobiles is not worth the effort and will incur huge cost pressure. Summary of the invention

[0006] The purpose of the present invention is to provide a wind speed monitoring method and system based on a reversing radar system, which utilizes the existing radar system of the original vehicle to assist in the echo surface layout design during vehicle body design, completes real-time monitoring of wind speed, and provides specific wind speed signal support for other vehicle systems without adding additional configuration.

[0007] To solve the above technical problems, the technical solution of the present invention is: a wind speed monitoring method based on a reversing radar system, comprising the following steps:

[0008] Two additional reversing radars are installed at a certain interval in the middle of the front and rear ends of the vehicle, and a reflector is installed above the radars;

[0009] Detect vehicle speed. When the vehicle speed exceeds the preset speed, start wind speed monitoring;

[0010] The radar controller controls the radars added at the front and rear ends to send and receive signals to different radars at the same end in an orderly manner through the reflectors, and analyzes the received radar echo signals through the radar controller;

[0011] Carry out calculation and analysis of wind direction and wind speed in the horizontal direction;

[0012] The wind speed and wind direction are synthesized based on calculation and analysis to generate a wind speed signal, which is then sent to the vehicle controller.

[0013] The calculation method of the wind speed in the horizontal direction perpendicular to the driving direction is:

[0014]

[0015]

[0016] This formula takes the calculation of the wind speed of the first and second reversing radars set at the front end in the horizontal direction perpendicular to the driving direction as an example, where x is the distance from a reversing radar to the middle of the reflector, T 12 T is the time from the first reversing radar sending out to the second reversing radar receiving. 21 V is the time required for the second reversing radar to send out and the first reversing radar to receive. L is the wind speed, V x For the wind speed V L The radar wave propagation speed under T 21 and T 12 θ is the time difference between the radar wave and the reflector;

[0017] Since V x is much smaller than the speed of light c, so

[0018]

[0019]

[0020]

[0021] Where, f is the frequency of the reversing radar wave speed, is the actual measured value of the phase difference between the two reversing radar receiving signals, and Δα is the theoretical value of the phase difference between the two reversing radar receiving signals;

[0022] Therefore, the lateral wind speed V x12前 for:

[0023]

[0024] In the formula, and The first reversing radar sends a radar wave signal received by the second reversing radar and the second reversing radar sends a radar wave signal received by the first reversing radar respectively.

[0025] Similarly, the lateral wind speed V at the rear side is calculated x34后 for:

[0026]

[0027] In the formula, and The third reversing radar sends a radar wave signal received by the fourth reversing radar and the fourth reversing radar sends a radar wave signal received by the third reversing radar respectively.

[0028] Take V x12前 and V x34后 The average value of the lateral wind speed V x校正 .

[0029] The method for calculating the wind speed in the driving direction is as follows: when the wind direction is the same as the driving direction, the average value of the measurements of the third and fourth reversing radars is taken as the longitudinal wind speed V y When the wind direction is opposite to the driving direction, the average value of the measurement values ​​of the first reversing radar and the second reversing radar is taken as the longitudinal wind speed V y ; When the measured wind speed is much smaller than the vehicle speed V 0 When V y =V 0 .

[0030] The synthesis method of wind speed and wind direction is:

[0031] V 2 =V x校正 2 +V y 2

[0032]

[0033] Where V is the wind speed and β is the wind direction angle.

[0034] The default speed is 11km / h.

[0035] A wind speed monitoring system based on a reversing radar system is also provided, comprising:

[0036] Two reversing radars are added at a certain interval in the middle of the front end and the middle of the rear end of the vehicle, and a reflector is respectively arranged above the radars;

[0037] A vehicle speed detector, used to detect vehicle speed;

[0038] The radar controller is used to start wind speed monitoring when the vehicle speed exceeds a preset speed; control the radars added at the front and rear ends to send and receive signals to different radars located at the same end through reflectors in an orderly manner, and analyze the received radar echo signals through the radar controller; perform calculation and analysis of wind direction and wind speed in the horizontal direction; synthesize wind speed and wind direction according to the calculation and analysis to generate a wind speed signal, and send it to the vehicle controller.

[0039] The calculation method of the wind speed in the horizontal direction perpendicular to the driving direction is:

[0040]

[0041]

[0042] This formula takes the calculation of the wind speed of the first and second reversing radars set at the front end in the horizontal direction perpendicular to the driving direction as an example, where x is the distance from a reversing radar to the middle of the reflector, T 12 T is the time from the first reversing radar sending out to the second reversing radar receiving. 21 V is the time required for the second reversing radar to send out and the first reversing radar to receive. L is the wind speed, V x For the wind speed V L The radar wave propagation speed under T 21 and T 12 θ is the time difference between the radar wave and the reflector;

[0043] Since V x is much smaller than the speed of light c, so

[0044]

[0045]

[0046]

[0047] Where, f is the frequency of the reversing radar wave speed, is the actual measured value of the phase difference between the two reversing radar receiving signals, and Δα is the theoretical value of the phase difference between the two reversing radar receiving signals;

[0048] Therefore, the lateral wind speed V x12前 for:

[0049]

[0050] In the formula, and The first reversing radar sends a radar wave signal received by the second reversing radar and the second reversing radar sends a radar wave signal received by the first reversing radar respectively.

[0051] Similarly, the lateral wind speed V at the rear side is calculated x34后 for:

[0052]

[0053] In the formula, and The third reversing radar sends a radar wave signal received by the fourth reversing radar and the fourth reversing radar sends a radar wave signal received by the third reversing radar respectively.

[0054] Take V x12前 and V x34后 The average value of the lateral wind speed V x校正 .

[0055] The method for calculating the wind speed in the driving direction is as follows: when the wind direction is the same as the driving direction, the average value of the measurements of the third and fourth reversing radars is taken as the longitudinal wind speed V y When the wind direction is opposite to the driving direction, the average value of the measurement values ​​of the first reversing radar and the second reversing radar is taken as the longitudinal wind speed V y ; When the measured wind speed is much smaller than the vehicle speed V 0 When V y =V 0 .

[0056] The synthesis method of wind speed and wind direction is:

[0057] V 2 =V x校正 2 +V y 2

[0058]

[0059] Where V is the wind speed and β is the wind direction angle.

[0060] The default speed is 11km / h.

[0061] Compared with the prior art, the present invention has the following beneficial effects:

[0062] Safety benefits: The present invention can accurately measure the wind speed of a car while it is driving, and provide complete development logic and algorithms for each function, with complete safety considerations.

[0063] Economic benefit: The wind speed measurement function can be completed without adding other equipment, saving costs.

[0064] Potential customer benefits: Popularizing the system to every car model will give the company's products a new functional selling point and provide safety protection for the majority of customers.

[0065] Enterprise benefits: The present invention is simple and practical, suitable for all types of vehicles, can interact with various types of reversing radar systems, and operate in a modular manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 is a flow chart of a method according to an embodiment of the present invention;

[0067] Figure 2 is a system structure diagram of an embodiment of the present invention;

[0068] Figure 3 A schematic diagram of the arrangement positions of the first reversing radar and the second reversing radar in an embodiment of the present invention;

[0069] Figure 4 This is a MAP diagram of the relationship between wind speed and echo strength in the embodiment of this announcement;

[0070] In the figure, 1-the first reversing radar, 2-the second reversing radar, 3-the third reversing radar, 4-the fourth reversing radar, 5-the first reflector, 6-the second reflector, 7-the front bumper, 8-the radar controller, and 9-the CAN bus. DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0072] The technical solution of the present invention is:

[0073] Step 1: Function activation and vehicle speed determination

[0074] The system reads the vehicle speed signal on the CAN bus and reads the function judgment signal in the reversing radar controller. If the radar controller 8 and the corresponding necessary current state are normal standby, and the front and rear center 4 radar states are waiting and no fault; when the vehicle speed exceeds 11km / h (calibrable), the wind speed measurement function of the present invention is requested to be turned on.

[0075] Step 2: Sending and receiving radar waves

[0076] The radar controller 8 controls the four radars in the front, back and middle to send out measurement radar waves in order; the radar waves are received by the radar on the other side after passing through the reflector, and the received radar echo signals are analyzed and processed by the radar controller 8. Subsequent steps: radar wave analysis and wind speed conversion

[0077] Step 3: Analysis and calculation of wind speed perpendicular to the driving direction (X direction) (taking the front protection as an example)

[0078] Depend on Figure 3 It can be seen that the propagation distance of ultrasonic waves in the absence of wind is 2X. To ensure the accuracy of the positions of the four sensors, they can be constrained during vehicle model and process design. 12 T is the time from the first reversing radar 1 sending out to the second reversing radar 2 receiving. 21 V is the time required for the second reversing radar 2 to be sent and the first reversing radar 1 to receive. The propagation speed of the reversing radar sound wave in the air is affected by the wind speed, so the propagation speed of the reversing radar wave in the air is set to V L The wind speed is V x , after combining them, we can get the relationship between wind speed, wind direction angle and ultrasonic transmission time difference.

[0079]

[0080]

[0081] Since V x is much smaller than the speed of light c, so

[0082] The time when the reversing radar sends out the sound wave signal is recorded as t 0 At time t, the other reversing radar receives 1 At the moment, the transmission time difference of 1 send and 2 receive or 2 send and 1 receive is Δt = t 1 -t 0 ; Record the transmission phase relationship of 1 transmit and 2 receive or 2 transmit and 1 receive respectively, such as Figure 3 shown.

[0083] The reversing radar wave speed frequency is f, and its phase difference is Δα (theoretical value) / (measure actual value).

[0084]

[0085]

[0086] in is the phase difference of the received signals of the two reversing radars. The relationship between the wind speeds can be derived as follows.

[0087] The transmission phase difference of recording 1 transmission and 2 reception or 2 transmission and 1 reception is Finally, the velocity component and wind direction angle are obtained.

[0088]

[0089]

[0090] V The corrected lateral wind speed on the same side (front)

[0091]

[0092] Step 4: Supplementary calculation and correction of wind speed perpendicular to the driving direction (X direction)

[0093] Similarly, the same calculation operation is performed on the third and fourth rear parking radars to correct the error. x Make corrections.

[0094] Similarly, the lateral wind speed V at the rear of the vehicle is measured x34后 ;

[0095] V x12前 With V x34后 Take the average value to get the average lateral wind speed;

[0096] Finally, the lateral wind speed value V is obtained. x校正 .

[0097] Step 5: Analysis and calculation of wind speed parallel to the driving direction (y direction)

[0098] Due to the wind resistance structure and characteristics of the vehicle during driving, the speed of the vehicle is assumed to be V in this calculation. 0 The radar controller reads directly through the CAN bus. Since the CAN bus speed is derived from the combined speed of the 4-wheel speeds of the ESC system and is subject to strict standards, its vehicle speed signal is absolutely accurate.

[0099] Assume the following statement:

[0100] When the wind speed is in the same direction as the vehicle's travel direction and the wind speed is greater than V 0 When the threshold is certain, it is expressed as "tailwind"

[0101] When the wind speed is opposite to the vehicle's direction, or the wind speed is less than V 0 When the threshold is certain, it is expressed as "headwind"

[0102] When the wind speed is V 0 Within a certain threshold, it is described as "weak phoenix"

[0103] Since the interference area size of the FOV radiation area of ​​the vehicle's reflector is fixed, the size of the radar echo received by its other radar should be a relatively fixed value A.

[0104] When the vehicle moves relative to the radar wave, the radar echo will be projected onto the reflector more or less, and the size of the radar echo received by another radar is a, and the value of a is different from A.

[0105] When conducting wind dynamic tests during automobile development, it is necessary to perform wind dynamic calibration of the function of the present invention. In the example, the rear wind Vg is calibrated when the vehicle is stationary, and the front wind Vh is calibrated similarly; the following figure is only a schematic diagram of the rear wind calibration of a certain model. In actual development, it is closely related to the radar wave reflection FOV and the vehicle structure layout, so the calibration lines of each model are quite different.

[0106] The wind speed and echo strength MAP diagram is as follows Figure 4 shown.

[0107] The radar controller reads the size of the radar echo respectively 前12 、a 前21 , find its average value a 前 ; Read the size of the radar echo a 后34 、a 后43 , find its average value a 后 ; The standard reference value of the front and rear echoes when stationary is A 前 ,A 后 ; The measurement robustness threshold is B.

[0108]

[0109] 1. If it is determined to be a tailwind, the radar controller reads the rear radar MAP and sets a 后 Substitute the corresponding wind speed Vg into the MAP diagram, then V y实际 =Vg+V 0 ; V y =Vg;

[0110] 2. If it is judged to be a headwind, the radar controller reads the forward radar MAP and sets a 前 Substitute the corresponding wind speed Vh into the MAP diagram, then V y实际 =Vh-V 0 ; V y =Vh

[0111] 3. If it is judged as other situations, it means that the wind speed is much smaller than V 0 , which has little interference on the car, so V y =V 0 (Note that the actual y-direction wind speed is of little reference value when the car is moving, so the subsequent system removes the relative wind speed V y Participate in synthetic wind speed calculation)

[0112] V y Perform subsequent wind speed synthesis

[0113] Step 6: Synthesis of wind speed

[0114] V 2 =V x校正 2 +V y 2

[0115]

[0116] The size V of the composite wind speed (including the vehicle speed) and the wind direction angle β are calculated.

[0117] Step 7: Sending of wind speed signal

[0118] The radar controller sends the wind speed and wind direction information through the CAN bus for use by other controllers or functions.

[0119] The present invention has the following beneficial effects:

[0120] Safety benefits: The present invention can accurately measure the wind speed of a car while it is driving, and provide complete development logic and algorithms for each function, with complete safety considerations.

[0121] Economic benefits: Without adding other equipment, the wind speed measurement function can be completed, saving costs. Potential customer benefits: The system will be popularized to every car model, giving the company's products a new functional selling point (function decentralization) and providing safety protection for customers.

[0122] Enterprise benefits: The present invention is simple and practical, suitable for all types of vehicles, can interact with various types of reversing radar systems, and operate in a modular manner.

[0123] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A wind speed monitoring method based on a reversing radar system, characterized in that: The following steps are involved: Two additional reversing radars are installed at a certain interval in the middle of the front and rear ends of the vehicle, and a reflector is installed above the radars; Detect vehicle speed. When the vehicle speed exceeds the preset speed, start wind speed monitoring; The radar controller controls the radars added at the front and rear ends to send and receive signals to different radars at the same end in an orderly manner through the reflectors, and analyzes the received radar echo signals through the radar controller; Carry out calculation and analysis of wind direction and wind speed in the horizontal direction; The wind speed and wind direction are synthesized based on the calculation and analysis to generate a wind speed signal, and sent to the vehicle controller; The calculation method of the wind speed in the horizontal direction perpendicular to the driving direction is: This formula takes the calculation of the wind speed of the first and second reversing radars set at the front end in the horizontal direction perpendicular to the driving direction as an example, where x is the distance from a reversing radar to the middle of the reflector, T 12 T is the time from the first reversing radar sending out to the second reversing radar receiving. 21 V is the time required for the second reversing radar to send out and the first reversing radar to receive. L is the wind speed, V x For the wind speed V L The radar wave propagation speed under T 21 and T 12 θ is the time difference between the radar wave and the reflector; Since V x is much smaller than the speed of light c, so Where, f is the frequency of the reversing radar wave speed, is the actual measured value of the phase difference between the two reversing radar receiving signals, and Δα is the theoretical value of the phase difference between the two reversing radar receiving signals; Therefore, the lateral wind speed V x12 Before: In the formula, and The first reversing radar sends a radar wave signal received by the second reversing radar and the second reversing radar sends a radar wave signal received by the first reversing radar respectively. Similarly, the lateral wind speed V at the rear side is calculated x34 Then: In the formula, and The third reversing radar sends a radar wave signal received by the fourth reversing radar and the fourth reversing radar sends a radar wave signal received by the third reversing radar respectively. Take V x12 Front and V x34 The average value after that is taken as the lateral wind speed V x Correction.

2. The wind speed monitoring method based on the reversing radar system according to claim 1 is characterized in that: The method for calculating the wind speed in the driving direction is as follows: when the wind direction is the same as the driving direction, the average value of the measurements of the third and fourth reversing radars is taken as the longitudinal wind speed V y When the wind direction is opposite to the driving direction, the average value of the measurement values ​​of the first reversing radar and the second reversing radar is taken as the longitudinal wind speed V y ; When the measured wind speed is much smaller than the vehicle speed V0, take V y =V0.

3. The wind speed monitoring method based on the reversing radar system according to claim 2 is characterized in that: The synthesis method of wind speed and wind direction is: V 2 =V x校正 2 +V y 2 Where V is the wind speed and β is the wind direction angle.

4. The wind speed monitoring method based on the reversing radar system according to claim 1 is characterized in that: The default speed is 11km / h.

5. A system using the wind speed monitoring method based on a reversing radar system as claimed in claim 1, characterized in that: include: Two reversing radars are added at a certain interval in the middle of the front end and the middle of the rear end of the vehicle, and a reflector is respectively arranged above the radars; A vehicle speed detector, used to detect vehicle speed; The radar controller is used to start wind speed monitoring when the vehicle speed exceeds the preset speed; control the radars added at the front and rear ends to send and receive signals to different radars at the same end through reflectors in an orderly manner, and analyze the received radar echo signals through the radar controller; perform calculation and analysis of wind direction and wind speed in the horizontal direction; synthesize wind speed and wind direction according to the calculation and analysis to generate a wind speed signal, and send it to the vehicle controller; The calculation method of the wind speed in the horizontal direction perpendicular to the driving direction is: This formula takes the calculation of the wind speed of the first and second reversing radars set at the front end in the horizontal direction perpendicular to the driving direction as an example, where x is the distance from a reversing radar to the middle of the reflector, T 12 T is the time from the first reversing radar sending out to the second reversing radar receiving. 21 V is the time required for the second reversing radar to send out and the first reversing radar to receive. L is the wind speed, V x For the wind speed V L The radar wave propagation speed under T 21 and T 12 θ is the time difference between the radar wave and the reflector; Since V x is much smaller than the speed of light c, so Where, f is the frequency of the reversing radar wave speed, is the actual measured value of the phase difference between the two reversing radar receiving signals, and Δα is the theoretical value of the phase difference between the two reversing radar receiving signals; Therefore, the lateral wind speed V x12 Before: In the formula, and The first reversing radar sends a radar wave signal received by the second reversing radar and the second reversing radar sends a radar wave signal received by the first reversing radar respectively. Similarly, the lateral wind speed V at the rear side is calculated x34 Then: In the formula, and The third reversing radar sends a radar wave signal received by the fourth reversing radar and the fourth reversing radar sends a radar wave signal received by the third reversing radar respectively. Take V x12 Front and V x34 The average value after that is taken as the lateral wind speed V x Correction.

6. The system according to claim 5, characterized in that The method for calculating the wind speed in the driving direction is as follows: when the wind direction is the same as the driving direction, the average value of the measurements of the third and fourth reversing radars is taken as the longitudinal wind speed V y When the wind direction is opposite to the driving direction, the average value of the measurement values ​​of the first reversing radar and the second reversing radar is taken as the longitudinal wind speed V y ; When the measured wind speed is much smaller than the vehicle speed V0, take V y =V0.

7. The system according to claim 6, characterized in that The synthesis method of wind speed and wind direction is: Where V is the wind speed and β is the wind direction angle.

8. The system according to claim 5, characterized in that The default speed is 11km / h.

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