CN114954232A - A method and device for vehicle wading warning based on radar detection - Google Patents

Abstract

The present application discloses a vehicle wading warning method and device based on radar detection. The aerial height from the radar installation position to the ground or the water surface collected by the radar is obtained; whether the vehicle is wading is determined according to the change rate of the obtained aerial height; After wading, determining the maximum wading depth of the vehicle; judging whether the maximum wading depth exceeds a preset depth threshold; judging whether the vehicle is in a wading misjudgment state; Water wading alarm, which can judge whether the vehicle is wading in water even when there is foreign object interference on the water surface. Combined with the misjudgment of wading depth and the comprehensive analysis of wading depth, the situation of wading false alarm can be avoided and the vehicle wading alarm can be improved. The accuracy of the vehicle improves the intelligence of the detection and alarm when the vehicle is wading, avoids the dangerous situation of the user wading deeply in the water while driving, and provides more guarantees for safe travel.

Description

A method and device for vehicle wading warning based on radar detection

technical field

The present application relates to the technical field of vehicle wading detection, and in particular, to a radar detection-based vehicle wading warning method and device.

Background technique

With the widespread use of automobiles, the application scenarios of vehicles have also become diverse. Among the application scenarios of vehicles, vehicle wading scenarios have also become normalized. Vehicle wading scenarios mainly include stagnant road sections formed by vehicles entering low-lying places on the road, such as tunnels, road surfaces under overpasses, and puddles formed on non-hardened roads. When a vehicle is wading, it is often impossible to identify the wading depth of the vehicle with the naked eye. If the wading water level is too high, water will enter the vehicle and cause damage to the electronic system and components inside the vehicle.

In the related art, a laser range finder is added on the roof, and the distance from the roof to the water surface is measured by the laser range finder to determine the wading depth of the vehicle. However, due to the high data sampling frequency of the laser range finder, the sampled data If the amount is large, it will lead to high energy consumption and high data processing load during ranging. When the vehicle is driving on an uneven road, the measurement error of the laser rangefinder will increase significantly, and when there are foreign objects on the water surface, water surface refraction or water surface reflection, the measurement error of the laser rangefinder will also increase. .

Therefore, how to accurately determine the wading condition of the vehicle when the vehicle is wading in water, and issue a wading reminder to the driver is a technical problem that needs to be solved urgently.

SUMMARY OF THE INVENTION

The main purpose of the present application is to provide a vehicle wading warning method, device and device based on radar detection, which aims to solve the problem of how to accurately determine the wading situation of the vehicle when the vehicle is wading, and how to issue a wading reminder to the driver. technical problem.

In a first aspect, the present application provides a vehicle wading warning method based on radar detection, the method comprising the following steps:

Obtain the airborne height from the radar installation position to the ground or water surface collected by the radar;

Determine whether the vehicle is wading according to the change rate of the obtained airborne height;

After determining the wading, determining the maximum wading depth of the vehicle;

determining whether the maximum wading depth exceeds a preset depth threshold;

Determine whether the vehicle is in a water-wading misjudgment state;

Based on the two judgment results, it is determined whether or not to issue a wading alarm.

In some embodiments, the acquiring the aerial height from the installation position of the radar collected by the vehicle-mounted radar to the ground or the water surface further includes the following steps:

Filtering the airborne heights greater than the preset maximum height threshold and between the preset minimum height threshold and the calibration height, wherein the maximum height threshold is the height of the radar from the ground when the vehicle tires are just off the ground, and the minimum height threshold is The height of the radar from the ground when the vehicle is fully loaded, the calibrated height is the height of the radar from the ground when the vehicle is unloaded, and the calibrated height is less than the maximum height threshold and greater than the minimum height threshold;

Perform PID adjustment on the filtered flying height to get the real flying height;

According to the mapping relationship between the vertical acceleration of the vehicle corresponding to the filtered airborne height and the confidence of the corresponding true airborne height, the confidence of the true airborne height is determined, wherein the acceleration is related to the true airborne height. Confidence is negatively correlated;

Filter the real flying height whose confidence is lower than the preset confidence threshold to obtain a credible flying height.

In some embodiments, the determining whether the vehicle is wading in water according to the obtained change rate of the airborne height specifically includes the following steps:

Determine the rate of change of the airborne height obtained in multiple different time intervals;

Determine whether the absolute value of the rate of change of the previous time interval in any two adjacent time intervals is greater than or equal to the absolute value of the rate of change of the next time interval;

If the probability of occurrence of greater than and equal to in the judgment result is above the set probability threshold, it is determined that the vehicle is wading in water, otherwise, it is not wading.

In some embodiments, if the vehicle is in the wading misjudgment state including the vehicle passing through a pothole, determining whether the vehicle is in the wading misjudgment state specifically includes the following steps:

Determine whether the product of the rate of change of the airborne height in three consecutive time intervals is less than a preset value, and if so, the vehicle is in a state of passing through a pothole, otherwise, it is not in a state of passing through a pothole.

In some embodiments, if the vehicle is in the water wading misjudgment state including the vehicle is in the water wading road state, then determining whether the vehicle is in the water wading misjudgment state specifically includes the following steps:

If the vehicle stops the wading alarm after the water wading alarm is issued, determining whether the duration of stopping the wading alarm is greater than or equal to a preset time;

If so, the vehicle is in the state of leaving the wading road, and if not, it is not in the state of leaving the wading road.

In some embodiments, the determining whether to issue a water wading alarm according to the two judgment results specifically includes the following steps;

If the maximum wading depth does not exceed a preset depth threshold, a wading alarm is not issued;

If the maximum wading depth exceeds a preset depth threshold and the vehicle is in a wading misjudgment state, a wading alarm is not issued;

If the maximum wading depth exceeds a preset depth threshold and the vehicle is not in a wading misjudgment state, a wading alarm is issued.

In some embodiments, the depth threshold includes a first depth threshold and a second depth threshold. If the maximum wading depth exceeds a preset depth threshold and the vehicle is not in a wading misjudgment state, a wading message is issued. Alerting specifically includes the following steps:

When the maximum wading depth exceeds the first depth threshold and does not exceed the second depth threshold, and the vehicle is not in a wading misjudgment state, controlling the vehicle instrument indicator light to flash;

When the maximum wading depth exceeds the second depth threshold and the vehicle is not in a wading misjudgment state, control the vehicle instrument indicator light to be always on, and control the vehicle to issue a voice alarm reminder;

Wherein, the first depth threshold is the height of the vehicle tire thickness, and the second depth threshold is the height of the vehicle tire axle center.

In some embodiments,

When the vehicle is wading forward or backward, the specific steps of determining the maximum wading depth of the vehicle include:

Determine the first detected wading depth according to the calibrated height and the obtained suspended height;

A first right-angled triangle model is established according to the first detected wading depth and the vehicle's forward or caster angle to obtain a first reference distance, wherein the first reference distance includes the vehicle in the first right-angled triangle model The length of the side between the forward or backward angle and the right angle;

The first added distance is obtained by adding the first reference distance and the distance from the front end of the vehicle to the radar;

A second right-angled triangle model is established according to the first added distance and the vehicle forward or caster angle, so as to obtain and determine a second reference distance, wherein the second reference distance is the difference between the second right-angled triangle model and the second right-angled triangle model. The opposite side of the vehicle's forward or caster angle;

The maximum wading depth of the front and rear of the vehicle is calculated by the first trigonometric function according to the forward or caster angle of the vehicle, the first reference distance and the second reference distance.

In some embodiments,

When the vehicle is wading with a left tilt or a right tilt, the specific steps of determining the maximum wading depth of the vehicle include:

Determine the second detection wading depth according to the calibrated height and the obtained airborne height;

A third right-angled triangle model is established according to the second detected wading depth and the left or right inclination angle of the vehicle to determine the second added distance, wherein the second added distance is the third reference distance and the distance between the radar and the vehicle body The added distance of the spacing distance, the second added distance is the side length between the left or right leaning angle of the vehicle and the right angle in the third right-angled triangle model;

A fourth right-angled triangle model is established according to the third reference distance and the left or right leaning angle of the vehicle to obtain a fourth reference distance, wherein the fourth reference distance is the difference between the fourth right-angled triangle model and the left side of the vehicle. the opposite side of the inclination or right inclination;

According to the left or right leaning angle of the vehicle, the third reference distance and the fourth reference distance, the maximum wading depth on the left and right sides of the vehicle is determined through a second trigonometric function.

In a second aspect, the present application further provides a vehicle wading warning device based on radar detection, the device comprising:

an acquisition module, which acquires the aerial height from the radar installation position collected by the radar to the ground or the water surface; the first determination module is used for determining whether the vehicle is wading according to the change rate of the acquired aerial height;

a second determining module, configured to determine the maximum wading depth of the vehicle after wading is determined;

a first judgment module, which is used for judging whether the maximum wading depth exceeds a preset depth threshold;

a second judging module, which is used to judge whether the vehicle is in a wading misjudgment state;

The third determination module is used for determining whether to issue a water wading alarm according to the two determination results.

The present application provides a vehicle wading warning method and device based on radar detection, by obtaining the aerial height from the radar installation position collected by the radar to the ground or the water surface; After entering the water, determine the maximum wading depth of the vehicle; determine whether the maximum wading depth exceeds a preset depth threshold; determine whether the vehicle is in a wading misjudgment state; according to two judgment results, determine whether to issue a wading The water alarm can judge whether the vehicle is wading in water even when there is foreign object interference on the water surface. Combined with the misjudgment of the wading depth and the comprehensive analysis of the wading depth, it avoids the false alarm of wading and improves the safety of the vehicle wading alarm. The accuracy improves the intelligence of the detection and alarm when the vehicle is wading in water, avoids the danger of users wading deeply in the water while driving, and provides more guarantees for safe travel.

Description of drawings

In order to explain the technical solutions of the embodiments of the present application more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. For those of ordinary skill, other drawings can also be obtained from these drawings without any creative effort.

1 is a schematic flowchart of a radar detection-based vehicle wading warning method provided by an embodiment of the present application;

Figure 2 is a schematic diagram of the installation location of the radar;

Fig. 3 is a schematic diagram of suspended height filtering;

Figure 4 is a schematic diagram of the change of the airborne height when the vehicle is wading;

FIG. 5 is a schematic diagram of a vehicle leaning forward and wading in water;

Figure 6 is a schematic diagram of a right-angled triangle model when the vehicle is tilted forward and wading;

Figure 7 is a schematic diagram of a vehicle wading rightwards;

FIG. 8 is a schematic diagram of a right-angled triangle model when a vehicle is wading with a right inclination;

FIG. 9 is a schematic diagram of the change of the flying height when the vehicle is in a state of passing through a pothole;

Figure 10 is a schematic diagram of the change of the flying height when the vehicle is leaving the wading road;

11 is a schematic block diagram of a vehicle wading warning system based on radar detection;

FIG. 12 is a schematic block diagram of a vehicle wading warning device based on radar detection according to an embodiment of the present application;

The realization, functional characteristics and advantages of the purpose of the present application will be further described with reference to the accompanying drawings in conjunction with the embodiments.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The flowcharts shown in the figures are for illustration only, and do not necessarily include all contents and operations/steps, nor do they have to be performed in the order described. For example, some operations/steps can also be decomposed, combined or partially combined, so the actual execution order may be changed according to the actual situation.

Embodiments of the present application provide a radar detection-based vehicle wading warning method and device

Some embodiments of the present application will be described in detail below with reference to the accompanying drawings. The embodiments described below and features in the embodiments may be combined with each other without conflict.

Please refer to FIG. 1 , which is a schematic flowchart of a radar detection-based vehicle wading warning method according to an embodiment of the present application.

As shown in FIG. 1 , the method includes steps S1 to S6.

Step S1, obtaining the aerial height from the radar installation position collected by the radar to the ground or the water surface.

It is worth noting that, as shown in Figure 2, the radars in this application are two ultrasonic radars, which are respectively installed at the two rear-view mirrors of the vehicle. The radars can be composed of a radar bracket and a radar wire harness. The radar detection head of the radar bracket It is installed upside down, that is, the radar detector is perpendicular to the ground. The height between the radar installation position and the ground is the calibrated height collected by the radar; when the vehicle is not wading, the distance collected by the radar is the airborne height from the installation position of the radar to the ground; when the vehicle is wading, the distance collected by the radar is the distance from the radar installation position to the ground. The suspended height of the water surface.

As a preferred embodiment, as shown in FIG. 3 , after the airborne height collected by the radar is obtained, the airborne height is filtered and PID adjusted to obtain a real and credible airborne height, which is closer to the real situation.

Specifically, the highest height threshold Hint Distance High and the lowest height threshold Hint Distance Low are preset. Among them, the highest height threshold is the height of the radar from the ground when the vehicle tires are just off the ground, and the lowest height threshold is the height of the radar from the ground when the vehicle is fully loaded (usually -0.1m of the calibrated height).

Filter out the airborne height that is greater than the preset maximum height threshold, because theoretically, when the vehicle is running normally, the airborne height collected by the radar will not be greater than the height of the radar from the ground when the vehicle tires are just off the ground. When the collected airborne height is greater than the highest height threshold , it indicates that the radar may malfunction and the collected data is wrong. Therefore, the airborne heights greater than the preset maximum height threshold are filtered out to ensure the authenticity of the collected airborne heights.

Optionally, you can also filter out the airborne height between the preset minimum height threshold and the calibrated height, because when the vehicle is fully loaded, the height of the vehicle decreases and the distance between the radar and the ground is reduced, and the natural airborne height value collected by the radar will be Therefore, the airborne height between the minimum height threshold and the calibration height is filtered out, so that the wading depth can be judged more accurately according to the collected airborne height.

Further, when PID adjustment is performed on the filtered airborne height, the P coefficient in the PID is set to 0, and the I coefficient and D coefficient are set according to a certain ratio, so that the output airborne height is real and can be sticked to. match the real situation.

In some embodiments, while acquiring the airborne height collected by the radar, the acceleration in the vertical direction of the vehicle (Z-axis acceleration) will be obtained. The acceleration can reflect the degree of turbulence of the vehicle, and each airborne height has a corresponding vertical direction of the vehicle. acceleration. There is a corresponding relationship between the filtered airborne height and the acceleration in the vertical direction of the vehicle. There is also a corresponding relationship between the real airborne height after PID adjustment and the filtered airborne height. Therefore, the confidence between the vertical acceleration of the vehicle and the true airborne height can be set. The mapping relationship between degrees, and the speed is negatively related to the confidence of the true airborne height. Because the acceleration of the vehicle in the vertical direction is large, it means that the vehicle may be driving on an uneven road, causing the change of the airborne height collected by the radar, not because of wading. Therefore, the data collected when the vehicle is bumpy need to be filtered out. According to the mapping relationship between the vertical acceleration of the vehicle corresponding to the filtered airborne height and the confidence of the corresponding true airborne height, the confidence of the true airborne height is determined, and the confidence of the true airborne height is filtered. Real flying height, get the real and credible flying height.

Step S2: Determine whether the vehicle is wading according to the acquired change rate of the airborne height.

Specifically, determine the rate of change of the suspended height obtained in multiple different time intervals, and then determine whether the absolute value of the rate of change of the previous time interval in any two adjacent time intervals is greater than or equal to the absolute value of the rate of change of the next time interval . Judging multiple sets of data, if the probability of being greater than or equal to the multiple sets of judgment results is greater than the set probability threshold, it is determined that the vehicle is wading; Below the probability threshold, it is determined that the vehicle is not wading.

As a preferred embodiment, the change of the airborne height collected by the radar _over time can be regarded as the curve shown in FIG. When the vehicle actually wades into the water, the vehicle itself may shake or cause waves on the water surface. At this time, the airborne height detected by the radar is shown in Figure 4. The rate of change k of the flying height in the plurality of time intervals Δt ₁ , Δt ₂ . . . Δt _i is respectively determined. Compare the absolute value of the change rate of Δt ₁ |k ₁ | and the absolute value of the change rate of Δt ₂ |k ₂ | whether |k ₁ |≥| _{k 2} | |k ₃ |, |k ₃ | and |k ₄ |... | _ki -1| and | _ki |. If more than 80% of the comparison results of multiple groups of two adjacent time intervals are that the absolute value of the change rate of the previous time interval is greater than the absolute value of the change rate of the next time interval, that is, when the expected result is ξ≥0.8, it is considered that the vehicle involved water, otherwise, make sure the vehicle is not wading.

Step S3, after the wading is determined, determine the maximum wading depth of the vehicle.

When the vehicle is tilted like water, the detected wading depth is obtained by subtracting the obtained airborne height from the calibration height. Because the detection wading depth is the wading depth of the vehicle at the location where the radar is installed, when the vehicle is tilted, the maximum wading depth will far exceed the detection wading depth, and the maximum wading depth needs to be calculated.

As shown in FIGS. 5 and 6 , when the vehicle is tilted forward, the front of the vehicle wades the deepest, and when the vehicle is tilted backward, the rear of the vehicle wades the deepest. This embodiment describes the method for determining the maximum wading depth when the vehicle is tilted forward. The maximum wading depth is determined in the same way as the forward dip. When the vehicle is wading forward, determining the maximum wading depth of the vehicle specifically includes the following steps:

The first detected wading depth is obtained by subtracting the obtained suspended height from the calibrated height: Hs-Ha=Dd1, where Hs is the calibrated height, Ha is the suspended height, and Dd1 is the first detected wading depth.

A first right-angled triangle model is established according to the first detected wading depth Dd1 and the vehicle forward inclination angle α. In the first right-angled triangle model, the first detected wading depth Dd1 and the first reference distance X1 are used as two right-angled sides, and the first reference distance X1 is the side length between the vehicle forward inclination angle and the right angle in the first right-angled triangle model. According to the trigonometric function tanα=Dd1/X1, the first reference distance X1=Dd1/tanα can be derived.

The first added distance is obtained by adding the first reference distance X1 and the distance Lv1 from the front end of the vehicle to the radar.

A second right-angled triangle model is established according to the first added distance and the vehicle's forward inclination angle α. In the second right-angled triangle model, the first added distance and the second reference distance Y1 are used as right-angled sides, wherein the second reference distance Y1 is the side opposite to the vehicle forward inclination angle α in the second right-angled triangle model.

According to the trigonometric function tanα=Y1/(Lv1+X1), the second reference distance can be obtained:

Y1=(Lv+Dd1/tanα)*tanα.

Then, according to the maximum wading depth formula Dw1=((Lv1+Dd1/tanα)*tanα)*cosα, the maximum wading depth Dw1 can be calculated.

Further, as shown in FIG. 7 and FIG. 8 , when the vehicle leans to the left, the far left side of the vehicle wades the deepest, and when the vehicle leans right, the far right side of the vehicle wades the deepest. The method for determining the maximum wading depth when a vehicle is wading to the right is explained in the middle. Determining the maximum wading depth of a vehicle specifically includes the following steps:

The second detected wading depth when the vehicle is tilted to the right is obtained by subtracting the obtained airborne height from the calibrated height: Hs-Ha=Dd2, where Dd2 is the second detected height.

A third right-angled triangle model is established according to the second detected wading depth Dd2 and the right inclination angle β of the vehicle.

In the third right-angled triangle model, the second detection wading depth Dd2 and the second added distance are the right-angled sides, wherein the second added distance is the third reference distance X2 and the distance between the radar and the vehicle body (that is, the radar probe extends The second added distance is the length of the side between the right inclination angle β of the vehicle and the right angle in the second right triangle model. According to the trigonometric function formula tanβ=Dd2/(x+Lv2)x, the third reference distance X2=Dd2/tanβ-Lv2 is calculated.

A fourth right-angled triangle model is established according to the third reference distance X2 and the right inclination angle β of the vehicle. In the fourth right triangle model, the three reference distances X2 and the fourth reference distance Y2 are used as right-angle sides, wherein the fourth reference distance Y2 is the side opposite to the right inclination angle of the vehicle in the fourth right triangle model. The fourth reference distance Y2=(Dd2/tanβ-Lv2)*tanβ is calculated according to the trigonometric function company.

Then calculate the maximum wading depth when the vehicle leans to the right according to the second trigonometric function formula: Dw2=((Dd2/tanβ-Lv2)*tanβ)*cosα, where Dw2 is the maximum wading depth of the vehicle leaning to the right.

Step S4, judging whether the maximum wading depth exceeds a preset depth threshold.

In some embodiments, two wading depth thresholds are preset, the first wading depth threshold is the height of the vehicle tire thickness, which indicates that the vehicle is slightly wading; the second wading depth threshold is the height of the center of the vehicle tire axis, which indicates The vehicle is wading in deep water. The wading depth threshold may be preset according to the structure and model of the vehicle, or may be preset by the driver. This application does not specifically limit the wading depth threshold.

Step S5, judging whether the vehicle is in a wading misjudgment state.

The state of wading misjudgment mainly includes two states, namely the state of the vehicle passing through the pothole and the state of the vehicle leaving the wading road.

When the vehicle is in the state of passing through a pothole, the airborne height collected by the radar is shown in Figure 9. The specific steps of determining whether the vehicle is in a state of passing through a pothole include: multiplying the ratios of the airborne heights in any three continuous time intervals, and judging whether the multiplication result is less than a preset value; Otherwise, the vehicle is not in a pothole state.

In one embodiment, the change rates of the airborne heights in the three continuous intervals Δt _i1 , Δt _i2 and Δt _i3 are respectively K ₁ , K ₂ and K ₃ , and if K ₁ *K ₂ *K ₃ <0, the vehicle is determined to be After passing through the pothole, if K ₁ *K ₂ *K ₃ ≥ 0, it is determined that the vehicle has not passed through the pothole.

When the vehicle passes through a pothole, the maximum wading depth of the vehicle may be suddenly and briefly deepened. When the vehicle is out of water, the front wheels will move up, which may cause the rear of the vehicle to tilt backward, and the maximum wading depth of the rear of the vehicle may suddenly and briefly deepen. The wading exceeds the threshold, but this does not represent the true wading state of the vehicle. Therefore, these states are regarded as misjudgment states, and are eliminated when the water wading alarm is performed.

When the vehicle is leaving the wading road, the airborne height collected by the radar is shown in Figure 10. At the vehicle speed v ₁ , it is ensured that the vehicle is not stationary and only takes values for multiple positions once. The specific steps for determining whether the vehicle is in a state of leaving the water-filled road include:

If the wading alarm is stopped after the vehicle sends out the wading alarm, it is determined whether the duration of the wading alarm is greater than or equal to the preset time; state, if not, it is not in the state of leaving the wading road.

It is worth noting that when the vehicle leaves the wading road section, the front wheel goes up, and the angle of the vehicle's backward inclination increases, which may cause the wading depth of the rear of the vehicle to exceed the preset wading depth threshold. Therefore, after entering the non-alarm zone, the effective After the non-alarm duration reaches the preset time Δt _valid , it is regarded as leaving the wading road. Take these states as misjudgment states and eliminate them when wading alarms are made.

Step S6, according to the two judgment results, determine whether to issue a water wading alarm.

Specifically, whether to issue a wading alarm is determined according to a judgment result of whether the maximum wading depth of the vehicle exceeds a preset threshold and a judgment result of whether the vehicle is in a wading misjudgment state. If the maximum wading depth does not exceed the preset depth threshold, the wading alarm will not be issued; if the maximum wading depth exceeds the preset depth threshold and the vehicle is in a wading misjudgment state, it indicates the maximum wading depth of the vehicle at this time. It is not the real wading depth of the vehicle. It may be that the maximum wading depth caused by potholes and the vehicle leaving the wading road section exceeds the threshold, and the wading alarm will not be issued; if the maximum wading depth exceeds the preset depth threshold, and the vehicle is not in The wading misjudgment state means that the real maximum wading depth of the vehicle exceeds the threshold at this time, and a wading alarm is issued.

As a preferred embodiment, the depth threshold includes a first depth threshold and a second depth threshold. If the maximum wading depth exceeds a preset depth threshold and the vehicle is not in a wading misjudgment state, issuing a wading alarm specifically includes: The following steps:

When the maximum wading depth exceeds the first depth threshold and does not exceed the second depth threshold, and the vehicle is not in a wading misjudgment state, control the vehicle instrument indicator light to flash; when the maximum wading depth exceeds the second depth threshold , and the vehicle is not in the state of wading misjudgment, the indicator light of the control vehicle instrument is always on, and the vehicle is controlled to issue a voice alarm reminder to remind the driver that the water is too deep. Wherein, the first depth threshold is the height of the vehicle tire thickness, and the second depth threshold is the height of the vehicle tire axle center.

The present application proposes a vehicle wading warning method based on radar detection. The central unit receives the ground penetration information from the radar and the inclination information of the vehicle inertial navigation, and calculates the depth relative to the front or the last wading of the vehicle body based on the detection point. The depth of the water intrusion into the vehicle will be alarmed. According to the different wading depths, the alarm will be divided into three levels step by step; the intelligence level when wading at low speed is improved, and the user is prevented from wading in deep water while driving. Dangerous situation. And in this application, based on the height detection change of the radar and the change of the inertial navigation acceleration of the vertical axis (Z direction), the filtering algorithm is used to eliminate the false alarm scene; in the complex working condition that the water surface is blocked, and there are foreign objects that interfere with the water surface state, it can also be used. To accurately detect the maximum wading depth of the current most edge part of the vehicle. In summary, this scheme effectively improves the effective judgment of wading scenarios and provides more guarantees for safe travel.

Please refer to FIG. 12 , which is a schematic block diagram of a vehicle wading warning device based on radar detection according to an embodiment of the present application. The device can be used in a central controller.

As shown in FIG. 12 , the apparatus includes: an acquisition module, a first determination module, a second determination module, a first determination module, a second determination module and a third determination module.

The acquisition module is used to acquire the aerial height of the radar installation position collected by the radar to the ground or the water surface;

the first determination module, which is used for determining whether the vehicle is wading according to the acquired change rate of the airborne height;

the second determining module, configured to determine the maximum wading depth of the vehicle after the wading is determined;

the first judgment module, which is used for judging whether the maximum wading depth exceeds a preset depth threshold;

the second judgment module, which is used for judging whether the vehicle is in a wading misjudgment state;

The third determining module is used for determining whether to issue a water wading alarm according to the two judgment results.

The obtaining module is also used for: filtering the airborne height greater than the preset maximum height threshold and between the preset minimum height threshold and the calibration height, wherein the maximum height threshold is the distance between the radar and the ground when the vehicle tires are just off the ground. height, the minimum height threshold is the height of the radar from the ground when the vehicle is fully loaded, the calibrated height is the height of the radar from the ground when the vehicle is unloaded, and the calibrated height is less than the maximum height threshold and greater than the minimum height threshold;

Perform PID adjustment on the filtered flying height to get the real flying height;

According to the mapping relationship between the vertical acceleration of the vehicle corresponding to the filtered airborne height and the confidence of the corresponding true airborne height, the confidence of the true airborne height is determined, wherein the acceleration is related to the true airborne height. Confidence is negatively correlated;

Filter the true flying height whose confidence is lower than the pre-set confidence threshold to obtain a credible flying height.

The first determining module is further configured to: determine the rate of change of the suspended heights obtained in multiple different time intervals;

Determine whether the absolute value of the rate of change of the previous time interval in any two adjacent time intervals is greater than or equal to the absolute value of the rate of change of the next time interval;

If the probability of occurrence of greater than and equal to in the judgment result is above the set probability threshold, it is determined that the vehicle is wading in water, otherwise, it is not wading.

The second judgment module is also used to: determine whether the product of the rate of change of the airborne height in the three consecutive time intervals is less than a preset value, if so, the vehicle is in a state of passing through a pothole, otherwise, it is not in a state of passing through a pothole. state.

The second judging module is further configured to: if the vehicle stops the wading alarm after issuing the wading alarm, determine whether the duration of stopping the wading alarm is greater than or equal to a preset time;

If so, the vehicle is in the state of leaving the wading road, and if not, it is not in the state of leaving the wading road.

The third determining module is further configured to: if the maximum wading depth does not exceed a preset depth threshold, not to issue a wading alarm;

If the maximum wading depth exceeds a preset depth threshold and the vehicle is in a wading misjudgment state, a wading alarm is not issued;

If the maximum wading depth exceeds a preset depth threshold and the vehicle is not in a wading misjudgment state, a wading alarm is issued.

The third determining module is further configured to: when the maximum wading depth exceeds the first depth threshold and does not exceed the second depth threshold, and the vehicle is not in a wading misjudgment state, controlling the vehicle meter to indicate lights flash;

When the maximum wading depth exceeds the second depth threshold and the vehicle is not in a wading misjudgment state, control the vehicle instrument indicator light to be always on, and control the vehicle to issue a voice alarm reminder;

Wherein, the first depth threshold is the height of the vehicle tire thickness, and the second depth threshold is the height of the vehicle tire axle center.

The second determining module is further configured to: determine the first detected wading depth according to the calibrated height and the obtained suspended height;

A first right-angled triangle model is established according to the first detected wading depth and the vehicle's forward or caster angle to obtain a first reference distance, wherein the first reference distance includes the vehicle in the first right-angled triangle model The length of the side between the forward or backward angle and the right angle;

The first added distance is obtained by adding the first reference distance and the distance from the front end of the vehicle to the radar;

A second right-angled triangle model is established according to the first added distance and the vehicle forward or caster angle, so as to obtain and determine a second reference distance, wherein the second reference distance is the difference between the second right-angled triangle model and the second right-angled triangle model. The opposite side of the vehicle's forward or caster angle;

The maximum wading depth of the front and rear of the vehicle is calculated by the first trigonometric function according to the forward or caster angle of the vehicle, the first reference distance and the second reference distance.

The second determining module is further configured to: determine the second detection wading depth according to the calibrated height and the obtained suspended height;

A third right-angled triangle model is established according to the second detected wading depth and the left or right inclination angle of the vehicle to determine the second added distance, wherein the second added distance is the third reference distance and the distance between the radar and the vehicle body The added distance of the spacing distance, the second added distance is the side length between the left or right leaning angle of the vehicle and the right angle in the third right-angled triangle model;

A fourth right-angled triangle model is established according to the third reference distance and the left or right leaning angle of the vehicle to obtain a fourth reference distance, wherein the fourth reference distance is the difference between the fourth right-angled triangle model and the left side of the vehicle. the opposite side of the inclination or right inclination;

According to the left or right leaning angle of the vehicle, the third reference distance and the fourth reference distance, the maximum wading depth on the left and right sides of the vehicle is determined through a second trigonometric function.

It should be noted that those skilled in the art can clearly understand that, for the convenience and brevity of the description, the specific working process of the above-described device and each module and unit may refer to the corresponding process in the foregoing embodiment, which is not described here. Repeat.

It should be noted that, herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article or system comprising a series of elements includes not only those elements, It also includes other elements not expressly listed or inherent to such a process, method, article or system. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in the process, method, article or system that includes the element.

The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages or disadvantages of the embodiments. The above are only specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of various equivalents within the technical scope disclosed in the present application. Modifications or substitutions shall be covered by the protection scope of this application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. a vehicle wading warning method based on radar detection, is characterized in that, comprises the following steps: Obtain the airborne height from the radar installation position to the ground or water surface collected by the radar; Determine whether the vehicle is wading according to the change rate of the obtained airborne height; After determining the wading, determining the maximum wading depth of the vehicle; determining whether the maximum wading depth exceeds a preset depth threshold; Determine whether the vehicle is in a water-wading misjudgment state; Based on the two judgment results, it is determined whether or not to issue a wading alarm. 2. the vehicle wading warning method based on radar detection according to claim 1, is characterized in that, described obtaining the aerial height of the radar installation position collected by vehicle-mounted radar to ground or water surface also comprises the following steps: Filtering the airborne heights greater than the preset maximum height threshold and between the preset minimum height threshold and the calibration height, wherein the maximum height threshold is the height of the radar from the ground when the vehicle tires are just off the ground, and the minimum height threshold is The height of the radar from the ground when the vehicle is fully loaded, the calibrated height is the height of the radar from the ground when the vehicle is unloaded, and the calibrated height is less than the maximum height threshold and greater than the minimum height threshold; Perform PID adjustment on the filtered flying height to get the real flying height; According to the mapping relationship between the vertical acceleration of the vehicle corresponding to the filtered airborne height and the confidence of the corresponding true airborne height, the confidence of the true airborne height is determined, wherein the acceleration is related to the true airborne height. Confidence is negatively correlated; Filter the true flying height whose confidence is lower than the pre-set confidence threshold to obtain a credible flying height. 3. The vehicle wading warning method based on radar detection according to claim 1, wherein the determining whether the vehicle is wading in water according to the obtained change rate of the suspended height specifically comprises the following steps: Determine the rate of change of the airborne height obtained in multiple different time intervals; Determine whether the absolute value of the rate of change of the previous time interval in any two adjacent time intervals is greater than or equal to the absolute value of the rate of change of the next time interval; If the probability of occurrence of greater than and equal to in the judgment result is above the set probability threshold, it is determined that the vehicle is wading in water, otherwise, it is not wading. 4 . The vehicle wading warning method based on radar detection according to claim 1 , wherein, if the vehicle is in the wading misjudgment state including the vehicle passing through a pothole, then the vehicle is judged to be in a state of passing through a pothole. 5 . Whether it is in a water wading misjudgment state specifically includes the following steps: Determine whether the product of the rate of change of the airborne height in three consecutive time intervals is less than a preset value, and if so, the vehicle is in a state of passing through a pothole, otherwise, it is not in a state of passing through a pothole. 5 . The vehicle wading warning method based on radar detection according to claim 1 , wherein, if the vehicle is in the wading misjudgment state including the vehicle is in the state of leaving the wading road, it is determined that the vehicle is in the water wading misjudgment state. 6 . Whether the vehicle is in a wading misjudgment state specifically includes the following steps: If the vehicle stops the wading alarm after the water wading alarm is issued, determining whether the duration of stopping the wading alarm is greater than or equal to a preset time; If so, the vehicle is in the state of leaving the wading road, and if not, it is not in the state of leaving the wading road. 6 . The vehicle wading alarm method based on radar detection according to claim 1 , wherein, according to the two judgment results, determining whether to issue a wading alarm specifically comprises the following steps; 7 . If the maximum wading depth does not exceed a preset depth threshold, a wading alarm is not issued; If the maximum wading depth exceeds a preset depth threshold and the vehicle is in a wading misjudgment state, a wading alarm is not issued; If the maximum wading depth exceeds a preset depth threshold and the vehicle is not in a wading misjudgment state, a wading alarm is issued. 7. The vehicle wading warning method based on radar detection according to claim 6, wherein the depth threshold comprises a first depth threshold and a second depth threshold, if the maximum wading depth exceeds a preset depth threshold, and the vehicle is not in a wading misjudgment state, issuing a wading alarm specifically includes the following steps: When the maximum wading depth exceeds the first depth threshold and does not exceed the second depth threshold, and the vehicle is not in a wading misjudgment state, controlling the vehicle instrument indicator light to flash; When the maximum wading depth exceeds the second depth threshold and the vehicle is not in a wading misjudgment state, control the vehicle instrument indicator light to be always on, and control the vehicle to issue a voice alarm reminder; Wherein, the first depth threshold is the height of the vehicle tire thickness, and the second depth threshold is the height of the vehicle tire axle center. 8 . The vehicle wading warning method based on radar detection according to claim 1 , wherein when the vehicle leans forward or backwards to wad, the determining the maximum wading depth of the vehicle is specific to 8 . Steps include: Determine the first detected wading depth according to the calibrated height and the obtained suspended height; A first right-angled triangle model is established according to the first detected wading depth and the vehicle's forward or caster angle to obtain a first reference distance, wherein the first reference distance includes the vehicle in the first right-angled triangle model The length of the side between the forward or backward angle and the right angle; The first added distance is obtained by adding the first reference distance and the distance from the front end of the vehicle to the radar; A second right-angled triangle model is established according to the first added distance and the vehicle forward or caster angle, so as to obtain and determine a second reference distance, wherein the second reference distance is the difference between the second right-angled triangle model and the second right-angled triangle model. The opposite side of the vehicle's forward or caster angle; The maximum wading depth of the front and rear of the vehicle is calculated by the first trigonometric function according to the forward or caster angle of the vehicle, the first reference distance and the second reference distance. 9 . The vehicle wading warning method based on radar detection according to claim 1 , wherein when the vehicle is wading with a left tilt or a right tilt, the specific step of determining the maximum wading depth of the vehicle comprises the following steps: 10 . : Determine the second detection wading depth according to the calibrated height and the obtained airborne height; A third right-angled triangle model is established according to the second detected wading depth and the left or right inclination angle of the vehicle to determine the second added distance, wherein the second added distance is the third reference distance and the distance between the radar and the vehicle body The added distance of the spacing distance, the second added distance is the side length between the left or right leaning angle of the vehicle and the right angle in the third right-angled triangle model; A fourth right-angled triangle model is established according to the third reference distance and the left or right leaning angle of the vehicle to obtain a fourth reference distance, wherein the fourth reference distance is the difference between the fourth right-angled triangle model and the left side of the vehicle. the opposite side of the inclination or right inclination; According to the left or right leaning angle of the vehicle, the third reference distance and the fourth reference distance, the maximum wading depth on the left and right sides of the vehicle is determined through a second trigonometric function. 10. A vehicle wading warning device based on radar detection, characterized in that, comprising: an acquisition module, which uses the radar installation position acquired by the acquisition radar to the airborne height of the ground or water surface; a first determination module, which is used for determining whether the vehicle is wading according to the acquired change rate of the airborne height; a second determining module, configured to determine the maximum wading depth of the vehicle after wading is determined; a first judgment module, which is used for judging whether the maximum wading depth exceeds a preset depth threshold; a second judging module, which is used to judge whether the vehicle is in a wading misjudgment state; The third determination module is used for determining whether to issue a water wading alarm according to the two determination results.

Images