Vehicle braking distance early warning method and device, electronic equipment and vehicle

Abstract

The invention relates to a vehicle braking distance early warning method and device, electronic equipment and a vehicle. The method comprises the steps that the human eye position of a driver is obtained; determining the braking distance of the vehicle according to the driving state information of the vehicle; according to the human eye position and the braking distance, the projection position of a braking early warning line projected on a windshield of the vehicle is determined, and the braking early warning line is used for indicating the braking position of the vehicle; and according to the projection position, the brake early warning line is projected to a windshield through a head-up display device HUD of the vehicle. A driver can see the braking early warning line through the windshield in front of the sight line, so that the braking position of the vehicle is known, the driver can conveniently adjust the speed of the vehicle according to the braking early warning line, then the distance between the driver and the front vehicle is adjusted, the possibility of rear-end collision accidents caused by the fact that the driver cannot master the braking distance can be effectively avoided, and the driving safety is improved. Therefore, a driver can conveniently keep a necessary safe distance in the driving process, and the driving safety of the vehicle is guaranteed.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicles, and in particular, to a method, device, electronic device, and vehicle for warning of vehicle braking distance. Background Art

[0002] With the improvement of people's material living standards, more and more people buy vehicles as means of transportation. Driving safety is the focus of attention of manufacturers and consumers. Accurately mastering the braking distance of a vehicle plays a very important role in ensuring driving safety. However, in actual driving, vehicles travel at different speeds, and the braking distance is different. Thus, it is difficult for a driver to accurately judge the braking distance, and there are potential safety hazards to the driver's driving safety. Summary of the Invention

[0003] To overcome the problems in the related art, the present disclosure provides a method, device, electronic device, and vehicle for warning of vehicle braking distance.

[0004] According to a first aspect of an embodiment of the present disclosure, there is provided a method for warning of vehicle braking distance, the method including:

[0005] Obtaining the eye position of a driver;

[0006] Determining the braking distance of the vehicle according to the driving state information of the vehicle;

[0007] Determining the projection position of a braking warning line on the windshield of the vehicle according to the eye position and the braking distance, the braking warning line being used to indicate the braking position of the vehicle;

[0008] Projecting the braking warning line onto the windshield through a head-up display (HUD) device of the vehicle according to the projection position.

[0009] Optionally, the method further includes:

[0010] When a calibration instruction is obtained, emitting two lasers to the ground in front of the vehicle through a laser emission source to form a first laser point and a second laser point on the ground in front of the vehicle;

[0011] Projecting a calibration line onto the windshield through the HUD;

[0012] Adjusting the position of the calibration line on the windshield according to a received adjustment instruction to obtain a calibrated calibration line position;

[0013] Obtaining a first calibration point and a second calibration point on the windshield according to the calibration line position;

[0014] Determine the calibrated position of the human eye based on the coordinates of the first laser point, the second laser point, the first calibration point, and the second calibration point.

[0015] Optionally, the braking distance includes the shortest braking distance, the braking warning line is the shortest braking line, and the determining the projection position of the braking warning line on the windshield of the vehicle according to the human eye position and the braking distance includes:

[0016] Obtain the coordinates of the shortest braking line according to the shortest braking distance and the front overhang length of the vehicle; the shortest braking distance is the shortest braking distance of the vehicle at the current vehicle speed;

[0017] Determine the projection position of the shortest braking line on the windshield according to the coordinates of the shortest braking line and the coordinates corresponding to the human eye position, using the windshield function and the line of sight function of the vehicle.

[0018] Optionally, the braking distance includes the relative braking distance, the braking warning line is the relative braking line, and the determining the projection position of the braking warning line on the windshield of the vehicle according to the human eye position and the braking distance includes:

[0019] Obtain the coordinates of the relative braking line according to the relative braking distance and the front overhang length of the vehicle; the relative braking distance is the difference between the shortest braking distance of the vehicle and the shortest braking distance of the vehicle in front when there is a vehicle in front of the vehicle;

[0020] Determine the projection position of the relative braking line on the windshield according to the coordinates of the relative braking line and the coordinates corresponding to the human eye position, using the windshield function and the line of sight function of the vehicle.

[0021] Optionally, the braking warning line includes the shortest braking line or / and the relative braking line, and the projecting the braking warning line onto the windshield through the head-up display device HUD of the vehicle according to the projection position includes:

[0022] Project the shortest braking line onto the windshield through the HUD according to the projection position of the shortest braking line on the windshield;

[0023] Or / and,

[0024] Project the relative braking line onto the windshield through the HUD according to the projection position of the relative braking line on the windshield.

[0025] Optionally, the method further includes:

[0026] When it is detected that the opening degree of the brake pedal of the vehicle is greater than zero, determine the predicted braking distance of the vehicle in the current braking state;

[0027] Project, via the HUD, an auxiliary braking line for indicating the predicted braking distance on the windshield of the vehicle.

[0028] Optionally, the method further includes:

[0029] Generate the calibration instruction when a seat adjustment signal of the vehicle is received.

[0030] According to a second aspect of the embodiments of the present disclosure, there is provided a vehicle braking distance warning device, the device includes:

[0031] A first determination module configured to obtain the eye position of the driver;

[0032] A second determination module configured to determine the braking distance of the vehicle according to the driving state information of the vehicle;

[0033] A third determination module configured to determine the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance, the braking warning line being used to indicate the braking position of the vehicle;

[0034] A projection module configured to project the braking warning line onto the windshield through a head-up display (HUD) device of the vehicle according to the projection position.

[0035] According to a third aspect of the embodiments of the present disclosure, there is provided an electronic device, the electronic device includes:

[0036] A memory having a computer program stored thereon;

[0037] A processor configured to execute the computer program in the memory to implement the steps of the vehicle braking distance warning method provided in the first aspect of the present disclosure.

[0038] According to a fourth aspect of the embodiments of the present disclosure, there is provided a vehicle including the electronic device provided in the third aspect of the present disclosure.

[0039] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0040] In the above technical solution, first, the eye position of the driver is obtained; the braking distance of the vehicle is determined according to the driving state information of the vehicle; according to the eye position and the braking distance, the projection position of the braking warning line on the windshield of the vehicle is determined, and the braking warning line is used to indicate the braking position of the vehicle; according to the projection position, the braking warning line is projected onto the windshield through the head-up display (HUD) device of the vehicle. By projecting the braking warning line indicating the braking distance onto the windshield through the HUD, the driver can see the braking warning line through the windshield in front of the line of sight, thereby knowing the braking position of the vehicle, which is convenient for the driver to adjust the vehicle speed according to the braking warning line, and then adjust the distance from the vehicle in front, which can effectively avoid the possibility of a rear-end collision caused by the driver's inability to grasp the braking distance, thus facilitating the driver to maintain a necessary safety distance during driving and ensuring the driving safety of the vehicle.

[0041] Other features and advantages of the present disclosure will be described in detail in the following detailed implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification, and are used to explain the present disclosure together with the following detailed implementation, but do not constitute a limitation to the present disclosure. In the drawings:

[0043] Figure 1 is a flowchart of a vehicle braking distance warning method shown according to an exemplary embodiment.

[0044] Figure 2 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment.

[0045] Figure 3 is a schematic diagram of calibrating the eye position shown according to an exemplary embodiment.

[0046] Figure 4 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment.

[0047] Figure 5 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment.

[0048] Figure 6 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment.

[0049] Figure 7 is a schematic diagram of the display effect of the braking warning line on the windshield shown according to an exemplary embodiment.

[0050] Figure 8It is a schematic diagram showing the display effect of another braking warning line on the windshield according to an exemplary embodiment.

[0051] Figure 9 It is a flowchart of another vehicle braking distance warning method according to an exemplary embodiment.

[0052] Figure 10 It is a schematic diagram showing the display effect of another braking warning line on the windshield according to an exemplary embodiment.

[0053] Figure 11 It is a block diagram of a vehicle braking distance warning device according to an exemplary embodiment.

[0054] Figure 12 It is a block diagram of an electronic device according to an exemplary embodiment. Detailed implementation manners

[0055] Here, the exemplary embodiments will be described in detail, and the examples are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0056] It can be understood that the terms "first", "second", etc. in the present disclosure are used to describe various information, but this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other, and do not represent a specific order or importance level.

[0057] Furthermore, it can be understood that although the operations are described in a specific order in the drawings in the embodiments of the present disclosure, it should not be understood as requiring the operations to be performed in the specific order shown or in a serial order, or requiring all the operations shown to obtain the desired result. In a specific environment, multitasking and parallel processing may be advantageous.

[0058] It should be noted that all actions of obtaining signals, information, or data in this application are carried out on the premise of complying with the corresponding data protection regulations and policies of the country where the location is located and obtaining authorization from the owner of the corresponding device.

[0059] Figure 1 It is a flowchart of a vehicle braking distance warning method according to an exemplary embodiment, as Figure 1 shown, and includes the following steps:

[0060] In step S11, obtain the eye position of the driver.

[0061] Among them, the position of the driver's human eye is the position where the driver's eyes are located when the driver is sitting on the driver's seat in the vehicle cab.

[0062] Exemplarily, when the vehicle is stationary, the vehicle height remains stable. At this time, the body height H0 is obtained through the vehicle height sensor of the vehicle; when the vehicle is moving, the vehicle height changes. At this time, the body height H1 is obtained through the vehicle height sensor of the vehicle. When the body height changes from H0 to H1, the height of the driver's human eye position with reference to the ground also changes accordingly; in one implementation, when the vehicle is stationary, the height of the human eye position is Z, and when the vehicle is moving, the height of the human eye position is Z + H1 - H0; the body height is the vertical distance from the ground where the front wheel touches the ground to the highest point of the vehicle.

[0063] In step S12, the braking distance of the vehicle is determined according to the driving state information of the vehicle.

[0064] Among them, the braking distance of the vehicle is the distance that the vehicle needs to travel from when the driver steps on the brake pedal to send a braking signal until the vehicle completely stops. The braking distance is affected by various factors, which may include vehicle speed, performance of the braking system, driver reaction time, opening degree of the brake pedal, ground friction coefficient, etc.

[0065] In step S13, according to the human eye position and the braking distance, the projection position of the braking warning line on the windshield of the vehicle is determined. The braking warning line is used to indicate the braking position of the vehicle.

[0066] Exemplarily, based on the human eye position, the braking distance can be converted into the projection position on the windshield. The driver's perspective can see the superimposed image of the braking warning line and the ground displayed on the windshield based on this projection position, so that the driver can see the specific position of the braking warning line on the ground, achieving the effect of indicating the braking position.

[0067] In step S14, according to the projection position, the braking warning line is projected onto the windshield through the head-up display device HUD of the vehicle.

[0068] Exemplarily, the projection display device HUD (Head Up Display) can project the driving information required by the driver onto the windshield in front of the driver, so that the driver can see the driving information without leaving the line of sight as much as possible. The projected driving information can be set by the driver according to needs or pre-configured by the vehicle manufacturer; in the present disclosure, the braking warning line can be used as the driving information and projected onto the windshield of the vehicle according to the projection position.

[0069] In the above technical solution, the braking warning line for indicating the braking distance is projected on the windshield through the HUD, enabling the driver to see the braking warning line through the windshield in front of the line of sight, thereby knowing the braking position of the vehicle, facilitating the driver to adjust the vehicle speed according to the braking warning line, and then adjusting the distance from the vehicle in front, which can effectively avoid the possibility of a rear-end collision caused by the driver's inability to grasp the braking distance, thus facilitating the driver to maintain a necessary safety distance during driving and ensuring the driving safety of the vehicle.

[0070] Figure 2 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment, as Figure 2 shown, the method further includes the following steps:

[0071] In step S15, when a calibration instruction is obtained, two lasers are emitted towards the ground in front of the vehicle through a laser emission source to form a first laser point and a second laser point on the ground in front of the vehicle.

[0072] Exemplarily, the laser emission source can be a device that emits laser beams and is installed at a set position on the vehicle body according to calibration requirements. For example, as Figure 3 shown, it can be installed below the front bumper of the vehicle. At this position, the laser emission source can emit two laser bands towards the ground in front of the vehicle. When the two laser bands intersect the ground respectively, a first laser point and a second laser point can be formed on the ground in front of the vehicle.

[0073] Optionally, when the laser emission source emits lasers towards the ground in front of the vehicle, the emission direction can be set according to the specific vehicle. For example, the laser emission source emits two laser bands towards the ground directly in front of the vehicle. When the two laser bands intersect the ground respectively, a first laser point and a second laser point can be formed on the ground directly in front of the vehicle.

[0074] In step S16, a calibration line is projected on the windshield through the HUD.

[0075] Exemplarily, the calibration line can be a line or a frame horizontally displayed on the windshield, and the initial position of the calibration line can be set by default. The position of the calibration line on the windshield can also be adjusted by the driver.

[0076] In step S17, the position of the calibration line on the windshield is adjusted according to the received adjustment instruction to obtain the calibrated position of the calibration line.

[0077] Exemplarily, taking the calibration line as an example, after projecting the calibration line on the windshield, the driver can adjust the up and down height or left and right position of the calibration line based on their own perspective, generating corresponding adjustment instructions. When the vehicle receives the adjustment instructions, it adjusts the up and down height or left and right position of the calibration line on the windshield to obtain the calibrated position of the calibration line. In one implementation, the up and down height or left and right position of the calibration line on the windshield can be adjusted using the steering wheel buttons of the vehicle. In another implementation, the adjustment of the calibration line can be achieved by setting buttons or keys with calibration functions on the vehicle. For example, the buttons or keys can be provided with up, down, left, and right direction keys, and the adjustment of the up and down height or left and right position of the calibration line can be achieved by operating these direction keys. It can be understood that when the straight line formed by the first laser point and the second laser point is seen by the human eye to coincide with the calibration line on the windshield, it can be considered that this calibration is completed. At this time, the adjustment of the calibration line position can be stopped. When the position of the calibration line stops moving and reaches a certain duration, it is determined that the adjustment of the calibration line position is completed, and step S18 is executed. Or, after the adjustment of the calibration line position is completed, the driver triggers the confirmation button (such as the confirmation button on the steering wheel) to make the vehicle determine that the adjustment of the calibration line position is completed, and step S18 is executed.

[0078] In step S18, the first calibration point and the second calibration point on the windshield are obtained according to the calibration line position.

[0079] Among them, the first calibration point and the second calibration point are two points taken from the calibration line.

[0080] In step S19, the calibrated human eye position is determined according to the coordinates of the first laser point, the second laser point, the first calibration point, and the second calibration point.

[0081] Exemplarily, the coordinates are the coordinates of a two-dimensional plane determined based on the driver's perspective in the cab.

[0082] Figure 3 is a schematic diagram showing the calibration of the human eye position according to an exemplary embodiment, as Figure 3 shown, including the following steps:

[0083] Exemplarily, from the first laser point and the first calibration point, the straight line L1 can be obtained; from the second laser point and the second calibration point, the straight line L2 can be obtained; the human eye position can be determined after the straight lines L1 and L2 intersect.

[0084] In one implementation, based on the driver's perspective when sitting on the driver's seat, the coordinates of the first laser point are expressed as (x a , z a ), and the coordinates of the first calibration point are expressed as (x a1 , z a1), the coordinates of the second laser point are expressed as (x b , z b ), and the coordinates of the second calibration point are expressed as (x b1 , z b1 ); To facilitate understanding and display of the laser point and the calibration point, Figure 3 The view shown is the side view of the vehicle.

[0085] From the coordinates of the first laser point (x a , z a ) and the coordinates of the first calibration point (x a1 , z a1 ), the equation of the straight line L1 can be expressed as:

[0086] A a x + B a z + C a = 0, where A a = z a - z a1 , B a = x a1 - x a , C a = x a1 z a - x a z a1 ;

[0087] From the coordinates of the second laser point (x b , z b ) and the coordinates of the second calibration point (x b1 , z b1 ), the equation of the straight line L2 can be expressed as:

[0088] A b x + B b z + C b = 0, where A b = z b - z b1 , B b = x b1 - x b , C b = x b1 z b - x b z b1 ;

[0089] By solving the equations of the straight lines L1 and L2, it can be obtained that:

[0090] x0 = (B a C b - B b C a ) / (Bb A a -B a A b ),

[0091] z0 = (A a C b -A b C a ) / (B a A b -A a B b ), and taking it as the calibrated value of the human eye position, which can be represented by coordinate points, for example, the coordinates (x0, z0);

[0092] Among them, the coordinate system of each coordinate in the embodiments of the present disclosure can be a three-dimensional coordinate system with the grounding point of any vehicle front wheel and the ground as the coordinate origin. Among them, based on the driver's perspective in the cab, the direction where the human eye is to the left or right is used as the horizontal direction, which is the X-axis direction of the coordinate system, the direction where the human eye is up or down is used as the vertical direction, which is the Z-axis direction of the coordinate system, and the direction of vehicle travel is used as the Y-axis direction of the coordinate system. Based on the driver's perspective in the cab, we can project the above-mentioned first laser point, second laser point, first calibration point, and second calibration point onto the two-dimensional plane formed by the X-axis and the Z-axis. Therefore, the coordinates (x a , z a ), (x b , z b ), (x a1 , z a1 ), (x b1 , z b1 ) of the above-mentioned first laser point, second laser point, first calibration point, and second calibration point are the coordinates in the two-dimensional plane formed by the X-axis and the Z-axis. Thus, based on the coordinates of the first laser point, second laser point, first calibration point, and second calibration point, the calibrated human eye position is determined, that is, the coordinate (x0, z0) is also a point on this two-dimensional plane.

[0093] Optionally, the method may further include:

[0094] When receiving the seat adjustment signal of the vehicle, generating a calibration instruction. Then, according to this calibration instruction, execute the above steps S15 to S19.

[0095] Exemplarily, when first using the braking distance warning function provided by the present disclosure, or when the vehicle detects a signal for the driver to adjust the seat, a calibration instruction can be generated.

[0096] Next, a method for determining the projection position of the braking warning line will be introduced:

[0097] Figure 4is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment. As Figure 4 shown, when the braking distance includes the shortest braking distance and the braking warning line is the shortest braking line, the step of determining the projection position of the braking warning line on the windshield of the vehicle according to the human eye position and the braking distance in step S13 may include the following steps:

[0098] In step S131, according to the shortest braking distance and the front overhang length of the vehicle, obtain the coordinates of the shortest braking line; the shortest braking distance is the shortest braking distance of the vehicle at the current vehicle speed.

[0099] It can be understood that the shortest braking distance may be the distance required to come to a complete stop from the start of braking when the vehicle reaches the maximum braking force (for example, the opening of the brake pedal is the largest). The maximum braking force may be determined by factors such as the performance of the vehicle braking system, the tire condition, the mass and power performance of the vehicle, and the road surface condition.

[0100] Exemplarily, the preset tire rolling radius of the vehicle is r, the wheel speed n can be obtained according to the vehicle wheel speed sensor, and the vehicle speed v can be determined by the formula v = 2nπr; according to the vehicle speed v, the following formula can be used to determine the shortest braking distance s when the vehicle reaches the maximum braking force at the current vehicle speed:

[0101] s = v2 / 2a + vt;

[0102] where a represents the braking acceleration of the vehicle, that is, the rate of deceleration when the vehicle brakes. For example, it can be 0.7g, which represents a multiple of the gravitational acceleration, and g represents the gravitational acceleration. When calculating the braking distance, g is usually taken as 9.8m / s 2 ; t is the time for the driver to react and the braking system to build pressure during the braking process, and usually can be taken as 0.2 - 0.5 seconds.

[0103] In the present disclosure, it is assumed that the braking acceleration during braking is constant, but the braking acceleration a and time t during the braking process can also be custom - set by the vehicle manufacturer according to the vehicle performance according to the actual situation.

[0104] According to the shortest braking distance s and the preset front overhang length L of the vehicle, it can be determined that the distance from the shortest braking line to the ground contact point of the vehicle front wheel is s + L. Based on the three - dimensional coordinate system with the ground contact point of the vehicle front wheel as the coordinate origin described above, the negative direction of the Y - axis is the forward direction of the vehicle, and vice versa is the positive direction of the Y - axis. Therefore, in the plane formed by the Y - axis and the Z - axis (i.e., Figure 3The coordinates of the shortest brake line can be expressed as (-sL, 0); wherein the vehicle front overhang length is the distance between the front wheels and the front axle of the vehicle, and the front overhang length can be set by the vehicle manufacturer based on the vehicle's stability, handling, and driving experience.

[0105] In step S132, according to the coordinates of the shortest brake line and the coordinates corresponding to the human eye position, the projection position of the shortest brake line on the windshield is determined using the windshield function and the sight line function of the vehicle.

[0106] Among them, the sight function is a function used to represent the visual perception ability of the human eye when observing along the forward direction of the vehicle. For example, in the embodiment, the shortest brake line can be used as the target that the human eye needs to perceive, and the sight function can be obtained according to the coordinates of the human eye position and the coordinates of the shortest brake line. For example, the line equation is used to represent the sight function.

[0107] For example, in one implementation, according to step S11 and Figure 3 The embodiment can determine that when the vehicle is traveling, based on the plane formed by the X-axis and the Z-axis described above, the coordinates of the human eye position can be (x0, z0+H1-H0), and based on the plane formed by the Y-axis and the Z-axis described above, the coordinates of the shortest brake line are (-sL, 0). Then, illustratively, the linear equation of the sight line function can be determined by these two coordinates and can be expressed as:

[0108] A c x+B c z+C c =0, where A c =z0+H1-H0,B c =-sL-x0,C c =(-sL)(z0+H1-H0);

[0109] Since the above coordinate values ​​are in the same three-dimensional coordinate system, the projection position of the shortest brake line on the windshield can be determined by using the preset windshield function f(x) of the vehicle and the above sight function. Considering that when the height of the vehicle changes, the windshield function may also be affected by the height of the vehicle and cause errors. In order to obtain a more accurate calculation result, in one implementation, the windshield function can be corrected to z=f(x)+H1-H0.

[0110] The sight line function and the windshield function can be combined to find their intersection point, which can be used as the coordinates of the projection position of the shortest brake line on the windshield. The area of ​​the projection position can also be determined based on the coordinates.

[0111] Optionally, the top dead center of the projection position can be preset, using coordinates (XL , Z L ) represents the bottom dead center, with coordinates (X u , Z L ). During calculation, by restricting the conditions X ∈ [X L , X u and Z ∈ [Z L , Z u , the calculated values are prevented from exceeding the range.

[0112] In another implementation, considering the refraction or reflection of the windshield surface and light, a more complex mathematical model and optical theory can be used to establish the line-of-sight function g(x); since the shapes and characteristics of windshields of different manufacturers and different vehicle models are different, the windshield function f(x) can be obtained according to the actual situation of the vehicle's windshield (such as the shape profile and the installation angle on the vehicle), and the obtaining method can be, for example, fitting the windshield function f(x) through actual measurement data. The determination methods of the above-mentioned windshield function f(x) and line-of-sight function g(x) are exemplary and include but are not limited to this. The windshield function f(x) and line-of-sight function g(x) of different vehicles may be different and can be set according to the actual situation, and the present disclosure does not make a limitation.

[0113] Figure 5 is a flowchart of another vehicle braking distance warning method shown according to an exemplary embodiment. As Figure 5 shown, when the braking distance includes the relative braking distance and the braking warning line is the relative braking line, the step of determining the projection position of the braking warning line projected on the windshield of the vehicle according to the human eye position and the braking distance in step S13 includes the following steps:

[0114] In step S133, according to the relative braking distance and the front overhang length of the vehicle, the coordinates of the relative braking line are obtained; the relative braking distance is the difference between the shortest braking distance of the vehicle and the shortest braking distance of the vehicle in front when there is a vehicle in front of the vehicle.

[0115] It can be understood that the relative braking distance is the relative braking distance determined by the shortest braking distance of the vehicle itself and the shortest braking distance of the vehicle in front when there is a vehicle in front of the vehicle.

[0116] Exemplarily, the distance between the vehicle and the vehicle in front at any moment can be measured by the front radar installed on the vehicle. The distance from the vehicle in front measured by the front radar at T1 is d1, and the distance from the vehicle in front measured by the front radar at the previous moment T2 of T1 is d2. Then the relative speed dv corresponding to the time interval dt between time T1 and time T2 = |d1 - d2| / dt;

[0117] Assume that the preset tire rolling radius of the vehicle is r. At time T1, the wheel speed n1 can be obtained according to the vehicle wheel speed sensor, and the vehicle speed v1 at time T1 can be determined by the formula v = 2nπr. Then the vehicle speed of the vehicle in front at time T1 is v 前 = v1 + dv; According to the vehicle speed v1 of this vehicle and the vehicle speed v of the vehicle in front at time T1 前， The relative braking distance ds of this vehicle at time T1 can be determined by the following formula:

[0118] ds = v1 2 / 2a + v1t - (v1 + dv) 2 / 2g, where v1 2 / 2a + v1t can represent the shortest braking distance of this vehicle, and (v1 + dv) 2 / 2g can represent the shortest braking distance of the vehicle in front;

[0119] Among them, a represents the braking acceleration of the vehicle, that is, the rate of deceleration when the vehicle brakes. For example, it can be 0.7g, which represents a multiple of the gravitational acceleration. g represents the gravitational acceleration. When calculating the braking distance, g is usually taken as 9.8m / s 2 ; t is the time for the driver to react and the braking system to build pressure during the braking process of the vehicle, and it can usually be taken as 0.2 - 0.5 seconds.

[0120] In this disclosure, it is assumed that the braking acceleration during braking is constant, but during the braking process, the braking acceleration a and time t can also be custom - set by the vehicle manufacturer according to the vehicle's performance according to the actual situation.

[0121] According to the relative braking distance ds and the preset front overhang length L of the vehicle, it can be determined that the distance from the relative brake line to the ground contact point of the vehicle's front wheel is ds + L. Based on the coordinate system content described in step S131 above, the coordinate of the relative brake line can be expressed as (-ds - L, 0).

[0122] In step S134, according to the coordinates of the relative brake line and the coordinates corresponding to the human eye position, using the windshield function and the line - of - sight function of this vehicle, the projection position of the relative brake line on the windshield is determined.

[0123] Optionally, in one implementation, the relative brake line can be regarded as the target that the human eye vision needs to perceive, and the line - of - sight function can be obtained as a corresponding function according to the coordinates of the human eye position and the coordinates of the relative brake line. For example, a straight - line equation is used to represent the line - of - sight function.

[0124] Exemplarily, in one implementation, according to steps S11 and Figure 3The embodiment can determine that when the vehicle is moving, based on the plane formed by the X-axis and the Z-axis mentioned above, the coordinates of the human eye position can be (x0, z0+H1-H0), and based on the plane formed by the Y-axis and the Z-axis mentioned above, the coordinates relative to the brake line are (-ds-L, 0). For example, the linear equation of the sight line function can be determined by these two coordinates and can be expressed as:

[0125] A d x+B d z+C d =0, where A d =z0+H1-H0,B d =-ds-L-x0,C d =(-ds-L)(z0+H1-H0);

[0126] Since the above coordinate values ​​are in the same three-dimensional coordinate system, the projection position of the relative brake line on the windshield can be determined by using the preset windshield function f(x) of the vehicle and the above sight function. Considering that when the height of the vehicle changes, the windshield function may also be affected by the height of the vehicle and cause errors. In order to obtain a more accurate calculation result, in one implementation, the windshield function can be corrected to z=f(x)+H1-H0.

[0127] By combining the sight line function with the windshield function and finding their intersection, which is used as the coordinate of the projection position of the relative brake line on the windshield, the area of ​​the projection position can also be determined based on the coordinate.

[0128] In another implementation, a more complex mathematical model and optical theory can be used to establish the line of sight function g(x) while taking into account the refraction or reflection of the windshield surface and light. Since the shapes and characteristics of windshields of different manufacturers and different models are different, the windshield function f(x) can be obtained based on the actual conditions of the vehicle's windshield (e.g., shape profile, setting angle on the vehicle). The acquisition method can, for example, fit the windshield function f(x) through actual measurement data. The above-mentioned methods for determining the windshield function f(x) and the line of sight function g(x) are exemplary, including but not limited to these. The windshield function f(x) and the line of sight function g(x) of different vehicles may be different and can be set according to actual conditions, which is not limited in the present disclosure.

[0129] When the brake warning line includes the shortest brake line and / or the relative brake line, Figure 6 is a flow chart of another vehicle braking distance warning method according to an exemplary embodiment. Figure 6 As shown, the step S14 of projecting the brake warning line onto the windshield through the head-up display device HUD of the vehicle according to the projection position includes the following steps:

[0130] In step S141, according to the projection position of the shortest braking line on the windshield, the shortest braking line is projected onto the windshield by the HUD.

[0131] In step S142, according to the projection position of the relative braking line on the windshield, the relative braking line of the vehicle is projected onto the windshield by the HUD.

[0132] It can be understood that at the same moment, the methods described in step S141 and step S142 can be executed simultaneously or only one of them can be executed. For example, when there is no vehicle in front of the vehicle, only the shortest braking line can be displayed; when there is a vehicle in front of the vehicle, the shortest braking line and the relative braking line can be displayed simultaneously. Among them, the vehicle in front can be understood as a vehicle in the same lane as the vehicle and in front of the vehicle. Whether there is a vehicle in front can be identified based on an in-vehicle camera for image recognition and / or through an in-vehicle lidar. The present disclosure does not limit this.

[0133] Figure 7 is a schematic diagram showing the display effect of a braking warning line on the windshield according to an exemplary embodiment, as Figure 7 shown, based on the forward driving direction of the vehicle, the vehicle simultaneously displays the shortest braking line and the relative braking line on the front windshield through the HUD, as Figure 7 shown, where the shortest braking line coincides with the vehicle in front. Since the shortest braking line is used to indicate the shortest braking distance, the coincidence of the shortest braking line with the vehicle in front means that the distance between the vehicle and the vehicle in front no longer meets the shortest braking distance of the vehicle. Whether the vehicle in front maintains its current driving state or brakes while driving, the vehicle may collide with the vehicle in front when braking in the current driving state. Therefore, when the driver sees that the shortest braking line coincides with the vehicle in front, the vehicle can be decelerated. As the vehicle decelerates, the distance between the vehicle and the vehicle in front becomes larger, and the shortest braking line gradually moves backward. When the shortest braking line no longer coincides with the vehicle in front, the driver can know that the distance between the vehicle and the vehicle in front has met the shortest braking distance at this time; by displaying the relative braking line, the driver can be prompted of the difference between the shortest braking distance of the vehicle and the shortest braking distance of the vehicle in front in the case of braking of the vehicle in front.

[0134] Therefore, by simultaneously displaying the shortest braking line and the relative braking line, the driver can be warned that the braking distance is insufficient under the current driving state and there may be a collision risk. Exemplarily, the shortest braking line and the relative braking line can be displayed by different colors and / or line styles. For example, the shortest braking line can be shown as a red solid line, and the relative braking line can be shown as an orange solid line. Herein, the colors of the shortest braking line and the relative braking line are only exemplary, and other color combinations can also be selected, which are not specifically limited in this disclosure.

[0135] Figure 8 FIG. 4 is a schematic diagram showing the display effect of another braking warning line on the windshield according to an exemplary embodiment, as Figure 8 shown. Exemplarily, in one implementation, when the assisted stop function is not turned on, only the shortest braking line is displayed on the vehicle windshield. In another implementation, based on the forward driving direction of the vehicle, if the shortest braking line is displayed on the vehicle front windshield through the HUD and the shortest braking line does not overlap with the vehicle ahead, it means that the braking distance between the vehicle and the vehicle ahead meets the shortest braking distance of the vehicle. When the vehicle ahead maintains the current driving state, the vehicle will not collide with the vehicle ahead when braking in the current driving state. At this time, the above-mentioned relative braking line may not be displayed. Exemplarily, the shortest braking line can be shown as a green (or other colors) solid line.

[0136] Figure 9 FIG. 10 is a flowchart of another vehicle braking distance warning method according to an exemplary embodiment, as Figure 9 shown, which further includes the following steps:

[0137] In step S20, when it is detected that the opening degree of the braking pedal of the vehicle is greater than zero, the predicted stopping distance of the vehicle in the current braking state is determined.

[0138] Exemplarily, the predicted stopping line can be turned on by the driver according to his own needs. When the vehicle detects that the opening degree of the braking pedal is greater than 0, the longitudinal acceleration value a0 of the vehicle when braking is obtained according to the longitudinal acceleration sensor. In one implementation, according to the vehicle speed v and the longitudinal acceleration a0, the predicted stopping distance s can be determined by the following formula a :

[0139] s a = v2 / 2a0 + vt, where t is the time for the driver's reaction and the braking system to build pressure during the braking process of the vehicle, and usually can take 0.2 - 0.5 seconds.

[0140] In step S21, an assisted stop line for indicating the predicted stopping distance is projected on the windshield of the vehicle through the HUD of the vehicle.

[0141] Exemplarily, determine the coordinates of the predicted braking line based on the predicted braking distance and the front overhang length; determine the projection position of the auxiliary braking line using a preset line-of-sight function and windshield function based on the coordinates corresponding to the human eye position and the coordinates of the measured braking line; project the auxiliary braking line onto the windshield of the vehicle through the vehicle's HUD according to the projection position.

[0142] Optionally, to ensure the accuracy of the auxiliary braking function, a preset braking pedal depression duration T can be set according to requirements. T can be in milliseconds, such as 1000 milliseconds, 2000 milliseconds, etc.; when the duration that the driver depresses the braking pedal exceeds T, calculate the projection position of the auxiliary braking line on the windshield; when the duration that the driver depresses the braking pedal is less than T, do not calculate the projection position of the auxiliary braking line on the windshield.

[0143] Optionally, when it is detected that the opening of the vehicle's braking pedal is equal to zero, or the vehicle speed is equal to zero, or the opening of the vehicle's accelerator pedal is greater than zero, stop displaying the auxiliary braking line.

[0144] Figure 10 It is a schematic diagram showing the display effect of another braking warning line on the windshield according to an exemplary embodiment, as Figure 10 shown. Exemplarily, display the auxiliary braking line and the shortest braking line on the windshield. Based on the forward driving direction of the vehicle, when the auxiliary braking line is displayed in front of the shortest braking line, it reminds the driver that the vehicle is in a safe driving state and can be safely braked; Exemplarily, the auxiliary braking line can be shown as a blue dotted line, and the shortest braking line can be shown as a green solid line. Among them, the colors of the auxiliary braking line and the shortest braking line are only exemplary, and other color combinations can also be selected. The present disclosure does not make specific limitations.

[0145] Through the above solution, first obtain the driver's human eye position; determine the braking distance of the vehicle according to the driving state information of the vehicle; determine the projection position of the braking warning line projected on the windshield of the vehicle based on the human eye position and the braking distance. The braking warning line is used to indicate the braking position of the vehicle; project the braking warning line onto the windshield through the vehicle's head-up display device HUD according to the projection position. In the above technical solution, by projecting the braking warning line for indicating the braking distance onto the windshield through the HUD, the driver can see the braking warning line through the windshield in front of the line of sight, thereby knowing the braking position of the vehicle, facilitating the driver to adjust the vehicle speed according to the braking warning line, and then adjusting the distance from the vehicle in front, which can effectively avoid the possibility of the driver having a rear-end collision due to being unable to grasp the braking distance, thereby facilitating the driver to maintain a necessary safety distance during driving and ensuring the driving safety of the vehicle.

[0146] Figure 11A block diagram of a vehicle braking distance warning device shown according to an exemplary embodiment. Refer to Figure 11 , the vehicle braking distance warning device 1100 includes: an acquisition module 1110, a first determination module 1120, a second determination module 1130, and a projection module 1140.

[0147] The acquisition module 1110 is configured to acquire the eye position of the driver.

[0148] The first determination module 1120 is configured to determine the braking distance of the vehicle according to the driving state information of the vehicle.

[0149] The second determination module 1130 is configured to determine the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance, and the braking warning line is used to indicate the braking position of the vehicle.

[0150] The projection module 1140 is configured to project the braking warning line onto the windshield through the head-up display device HUD of the vehicle according to the projection position.

[0151] Optionally, the vehicle braking distance warning device 1100 further includes a calibration module 1150, which is configured to:

[0152] When a calibration instruction is obtained, two lasers are emitted to the ground in front of the vehicle through a laser emission source to form a first laser point and a second laser point on the ground in front of the vehicle;

[0153] Project a calibration line on the windshield through the HUD;

[0154] Adjust the position of the calibration line on the windshield according to the received adjustment instruction to obtain the calibrated calibration line position;

[0155] Obtain a first calibration point and a second calibration point on the windshield according to the calibration line position;

[0156] Determine the calibrated eye position according to the coordinates of the first laser point, the second laser point, the first calibration point, and the second calibration point.

[0157] Optionally, the braking distance includes the shortest braking distance, the braking warning line is the shortest braking line, and the second determination module 1130 is configured to:

[0158] Obtain the coordinates of the shortest braking line according to the shortest braking distance and the front overhang length of the vehicle; the shortest braking distance is the shortest braking distance of the vehicle at the current vehicle speed;

[0159] Determine the projection position of the shortest braking line on the windshield according to the coordinates of the shortest braking line and the coordinates corresponding to the eye position, using the windshield function and the line of sight function of the vehicle.

[0160] Optionally, the braking distance includes a relative braking distance, and the braking warning line is a relative braking line. The second determination module 1130 is configured to:

[0161] Obtain the coordinates of the relative braking line according to the relative braking distance and the front overhang length of the vehicle; the relative braking distance is the difference between the shortest braking distance of the vehicle and the shortest braking distance of the vehicle in front when there is a vehicle in front of the vehicle;

[0162] Determine the projection position of the relative braking line on the windshield by using the windshield function and the line of sight function of the vehicle according to the coordinates of the relative braking line and the coordinates corresponding to the position of the human eye.

[0163] Optionally, the braking warning line includes the shortest braking line or / and the relative braking line. The projection module 1140 is configured to:

[0164] Project the shortest braking line onto the windshield through the HUD according to the projection position of the shortest braking line on the windshield;

[0165] Or / and,

[0166] Project the relative braking line onto the windshield through the HUD according to the projection position of the relative braking line on the windshield.

[0167] Optionally, the vehicle braking distance warning device 1100 further includes a prediction module 1160, which is configured to:

[0168] When it is detected that the opening of the vehicle's brake pedal is greater than zero, determine the predicted stopping distance of the vehicle in the current braking state;

[0169] Project an auxiliary stopping line for indicating the predicted stopping distance onto the windshield of the vehicle through the HUD.

[0170] Optionally, the calibration module 1150 is further configured to:

[0171] Generate a calibration instruction when receiving a seat adjustment signal of the vehicle.

[0172] Regarding the device in the above embodiments, the specific manners in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0173] Through the above solution, first obtain the eye position of the driver; determine the braking distance of the vehicle according to the driving state information of the vehicle; determine the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance, where the braking warning line is used to indicate the braking position of the vehicle; project the braking warning line onto the windshield through the head-up display (HUD) of the vehicle according to the projection position. This enables the driver to see the braking warning line through the windshield in front of the line of sight, thereby knowing the braking position of the vehicle, facilitating the driver to adjust the vehicle speed according to the braking warning line, and then adjusting the distance from the vehicle in front. It can effectively avoid the possibility of a rear-end collision caused by the driver's inability to grasp the braking distance, thus facilitating the driver to maintain a necessary safety distance during driving and ensuring the driving safety of the vehicle.

[0174] Figure 12 It is a block diagram of an electronic device 1200 shown according to an exemplary embodiment. As Figure 12 shown, the electronic device 1200 may include: a processor 1201, a memory 1202. The electronic device 1200 may further include one or more of a multimedia component 1203, an input / output (I / O) interface 1204, and a communication component 1205.

[0175] Among them, the processor 1201 is used to control the overall operation of the electronic device 1200 to complete all or part of the steps in the above vehicle braking distance warning method. The memory 1202 is used to store various types of data to support the operation of the electronic device 1200. These data may include, for example, instructions for any application or method operating on the electronic device 1200, as well as application-related data, such as contact data, sent and received messages, pictures, audio, video, and so on. The memory 1202 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic memory, flash memory, a magnetic disk, or an optical disc. The multimedia component 1203 may include a screen and an audio component. The screen may be, for example, a touch screen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signal may be further stored in the memory 1202 or sent through the communication component 1205. The audio component further includes at least one speaker for outputting audio signals. The I / O interface 1204 provides an interface between the processor 1201 and other interface modules. The above other interface modules may be a keyboard, a mouse, buttons, etc. These buttons may be virtual buttons or physical buttons. The communication component 1205 is used for wired or wireless communication between the electronic device 1200 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IOT, eMTC, or other 5G, etc., or a combination of one or more of them, is not limited herein. Accordingly, the communication component 1205 may include: a Wi-Fi module, a Bluetooth module, an NFC module, and so on.

[0176] In an exemplary embodiment, the electronic device 1200 may be implemented by one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components, and is used to execute the above-mentioned vehicle braking distance warning method.

[0177] In another exemplary embodiment, a computer-readable storage medium including program instructions is further provided. When the program instructions are executed by a processor, the steps of the above-mentioned vehicle braking distance warning method are implemented. For example, the computer-readable storage medium may be the above-mentioned memory 1202 including program instructions, and the above-mentioned program instructions may be executed by the processor 1201 of the electronic device 1200 to complete the above-mentioned vehicle braking distance warning method.

[0178] The embodiment of the present disclosure further provides a vehicle including the above-mentioned electronic device, and the electronic device is used to execute the above-mentioned vehicle braking distance warning method on the vehicle. Among them, the vehicle may be a hybrid vehicle, or a non-hybrid vehicle, an electric vehicle, a fuel cell vehicle, or other types of vehicles. The vehicle may be an autonomous vehicle, a semi-autonomous vehicle, or a non-autonomous vehicle. The electronic device may be an in-vehicle device of the vehicle to complete all or part of the steps of the above-mentioned vehicle braking distance warning method.

[0179] The preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0180] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0181] In addition, any combination can be made between various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A vehicle braking distance warning method, characterized in that, The method includes: Obtaining the eye position of the driver; Determining the braking distance of the vehicle according to the driving state information of the vehicle; Determining the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance, where the braking warning line is used to indicate the braking position of the vehicle; Projecting the braking warning line onto the windshield through the head-up display (HUD) of the vehicle according to the projection position.

2. The method according to claim 1, wherein The method further includes: When a calibration instruction is obtained, emitting two lasers to the ground in front of the vehicle through a laser emission source to form a first laser point and a second laser point on the ground in front of the vehicle; Projecting a calibration line on the windshield through the HUD; Adjusting the position of the calibration line on the windshield according to the received adjustment instruction to obtain the calibrated position of the calibration line; Obtaining a first calibration point and a second calibration point on the windshield according to the calibrated position of the calibration line; Determining the calibrated eye position according to the coordinates of the first laser point, the second laser point, the first calibration point, and the second calibration point.

3. The method according to claim 1, wherein The braking distance includes the shortest braking distance, and the braking warning line is the shortest braking line. The step of determining the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance includes: Obtaining the coordinates of the shortest braking line according to the shortest braking distance and the front overhang length of the vehicle; the shortest braking distance is the shortest braking distance of the vehicle at the current vehicle speed; Determining the projection position of the shortest braking line on the windshield by using the windshield function and the line of sight function of the vehicle according to the coordinates of the shortest braking line and the coordinates corresponding to the eye position.

4. The method according to claim 1, characterized in that, The braking distance includes the relative braking distance, and the braking warning line is the relative braking line. The step of determining the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance includes: Obtaining the coordinates of the relative braking line according to the relative braking distance and the front overhang length of the vehicle; the relative braking distance is the difference between the shortest braking distance of the vehicle and the shortest braking distance of the vehicle in front when there is a vehicle in front of the vehicle; Determining the projection position of the relative braking line on the windshield by using the windshield function and the line of sight function of the vehicle according to the coordinates of the relative braking line and the coordinates corresponding to the eye position.

5. The method according to claim 1, characterized in that, The braking warning line includes the shortest braking line or / and the relative braking line. The step of projecting the braking warning line onto the windshield through the head-up display (HUD) of the vehicle according to the projection position includes: Projecting the shortest braking line onto the windshield through the HUD according to the projection position of the shortest braking line on the windshield; Or / and, Projecting the relative braking line onto the windshield through the HUD according to the projection position of the relative braking line on the windshield.

6. The method according to claim 1, characterized in that The method further includes: When it is detected that the opening degree of the brake pedal of the vehicle is greater than zero, determine the predicted stopping distance of the vehicle in the current braking state; Project an auxiliary stopping line for indicating the predicted stopping distance on the windshield of the vehicle through the HUD.

7. The method according to claim 2, characterized in that, The method further includes: Generate the calibration instruction when a seat adjustment signal of the vehicle is received.

8. A vehicle braking distance warning device, characterized in that, The device includes: An acquisition module configured to acquire the eye position of the driver; A first determination module configured to determine the braking distance of the vehicle according to the driving state information of the vehicle; A second determination module configured to determine the projection position of the braking warning line on the windshield of the vehicle according to the eye position and the braking distance, where the braking warning line is used to indicate the braking position of the vehicle; A projection module configured to project the braking warning line onto the windshield through the head-up display device (HUD) of the vehicle according to the projection position.

9. An electronic device, characterized in that, The electronic device includes: A memory on which a computer program is stored; A processor for executing the computer program in the memory to implement the steps of the method according to any one of claims 1-7.

10. A vehicle, characterized in that, An electronic device including the one in claim 9.

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