CN115871659A - Vehicle rear-end collision prevention method and system - Google Patents

Abstract

The invention discloses a method and a system for preventing rear-end collision of a vehicle. The method comprises the following steps: when the vehicle brakes, the braking deceleration and the braking pedal travel of the vehicle are obtained in real time, and the vehicle type information, the running speed relative to the vehicle and the distance relative to the vehicle of a rear vehicle are obtained in real time; if the running speed of the rear vehicle relative to the vehicle is less than zero, ending the method, otherwise, acquiring the ultimate braking deceleration of the rear vehicle according to the vehicle type information, the braking deceleration and the braking pedal stroke of the vehicle and the vehicle type information of the rear vehicle; calculating the limit safety distance between the rear vehicle and the vehicle according to the running speed of the rear vehicle relative to the vehicle and the limit braking deceleration of the rear vehicle; and judging whether the rear-end collision risk is encountered or not according to the limit safety distance and the distance between the rear vehicle and the vehicle, and if so, giving an alarm. The influence of environmental factors on rear vehicle braking can be considered, the rear-end collision risk of the vehicle can be accurately evaluated, and the effectiveness of alarm reminding is improved.

Description

Method and system for preventing rear-end collision of a vehicle

technical field

The invention relates to the technical field of automobile control, in particular to a vehicle rear-end collision prevention method and system.

Background technique

Rear-end collision accidents often occur when the vehicle in front brakes, and the vehicle behind does not brake in time. The possible reasons include: the driver's distraction, inaccurate judgment of the distance between vehicles, etc. At present, there are some vehicle-mounted technologies for early warning rear vehicles on the market, such as the specification of Chinese invention patent CN110803160A, which discloses a rearward anti-collision method for automobiles. When the distance of the vehicle behind is less than the safety distance, a reminder will be given. The safety distance is obtained by calculating the speed of the vehicle behind, the reaction time, and the maximum braking deceleration of the vehicle behind. Due to the design value of the maximum braking deceleration, it is generally on the road Adhesion and other environmental conditions are given, so that the existing rear-end collision possibility judgment does not take into account the difference between the actual braking of the rear vehicle and the theoretical maximum braking deceleration. Since the actual deceleration of the vehicle behind is not only related to its own braking performance, but also affected by environmental factors such as actual road conditions and weather conditions, it is often difficult for existing technologies to accurately assess the risk of being rear-ended by a vehicle behind, such as in rainy and snowy weather. The road surface is wet and slippery, and the braking performance of the vehicle is limited, which may cause the early warning reminder to lag behind and fail to play an effective reminder role.

Contents of the invention

The technical problem to be solved by the present invention is to provide a vehicle rear-end collision prevention method and system, which can consider the impact of environmental factors on the braking of the rear vehicle, more accurately assess the risk of the vehicle being rear-end collision, and improve the effectiveness of the alarm reminder.

In order to solve the above technical problems, a method for preventing rear-end collision of a vehicle of the present invention comprises the following steps:

Step 1: When the vehicle brakes, obtain the braking deceleration and brake pedal stroke of the vehicle in real time, and obtain the vehicle model information of the rear vehicle, the driving speed relative to the vehicle, and the distance relative to the vehicle in real time;

Step 2: If the speed of the following vehicle relative to the vehicle is less than zero, then end the method; otherwise, according to the vehicle model information, brake deceleration and brake pedal travel, and the vehicle model information of the vehicle, obtain the limit of the vehicle behind braking deceleration;

Step 3: According to the driving speed of the rear vehicle relative to the own vehicle, and the limit braking deceleration of the rear vehicle, calculate the limit safety distance between the rear vehicle and the own vehicle;

Step 4: According to the limit safety distance and the distance of the rear vehicle relative to the own vehicle, it is judged whether there is a risk of rear-end collision, and if so, an alarm is issued.

In the above vehicle rear-end collision prevention method, when the vehicle starts to brake, if the following vehicle will gradually approach the vehicle, then through the vehicle model information, braking deceleration and brake pedal travel, and the vehicle model information of the vehicle behind, Obtain the limit braking deceleration of the rear car, and then calculate the limit safety distance according to the limit braking deceleration of the rear car, and then judge whether it faces the risk of rear-end collision. Since the vehicle and the following vehicle are driving under the same environmental factors such as road conditions and weather, the relationship between the actual braking deceleration of the two vehicles is related to the models of the two vehicles, and because the actual braking deceleration of the vehicle combines the brake Force, road surface friction, wind resistance and other factors can be used to deduce the obtained braking deceleration of the rear vehicle, which can consider the impact of environmental factors on the braking of the rear vehicle, more accurately assess the risk of the vehicle being rear-ended, and improve the effectiveness of the alarm reminder. Sex, the whole idea is novel and ingenious.

As an improvement of the vehicle rear-end collision prevention method of the present invention, in step 2, the method for obtaining the limit braking deceleration of the rear vehicle includes:

Step a1: Obtain the vehicle model coefficient according to the model information of the own car and the model information of the following car;

Step a2: Obtain the deceleration coefficient according to the brake pedal travel of the vehicle;

Step a3: According to the vehicle model coefficient, the deceleration coefficient and the braking deceleration of the own vehicle, obtain the limit braking deceleration of the following vehicle.

Further, the step a1 includes: consulting the data set according to the vehicle model information of the own vehicle and the vehicle model information of the following vehicle to obtain the vehicle model coefficient, wherein the data set stores the vehicle model coefficient information of all vehicle models in one-to-one correspondence.

Further, the step a2 includes:

According to the brake pedal stroke of the vehicle and the pedal stroke-deceleration relationship curve of the vehicle, the theoretical braking deceleration value of the vehicle is obtained;

Acquire the deceleration coefficient according to the braking deceleration of the vehicle and the theoretical braking deceleration value.

Further, the step a3 includes: multiplying the vehicle type coefficient by the deceleration coefficient and multiplying by the deceleration of the own vehicle to obtain the limit braking deceleration of the following vehicle.

The vehicle type refers to the category of the vehicle. Preferably, all vehicle types are divided into three types according to the three regulations in the national automobile braking distance standard. It greatly simplifies the types of vehicle types, reduces a lot of work for formulating data sets, saves manpower and material resources, and also makes evaluation calculations fast, and thus rapid response.

As another improvement of the vehicle rear-end collision prevention method of the present invention, the third step includes: setting the following vehicle to perform a uniform deceleration movement from the current moment, the speed of the following vehicle relative to the own vehicle is the initial speed of the uniform deceleration movement, and the following vehicle The limit braking deceleration is used to decelerate, and the distance when the rear vehicle decelerates to zero is calculated as the limit safety distance.

As another improvement of the vehicle rear-end collision prevention method of the present invention, said step 4 includes:

Step b1: Calculate the optimal safety distance based on the limit safety distance and the reaction distance, where the reaction distance is the product of the driving distance of the following vehicle and the reaction time;

Step b2: compare the size relationship between the optimal safety distance and the distance between the rear vehicle and the vehicle;

Step b3: If the optimal safe distance is not less than the distance between the rear vehicle and the own vehicle, it is determined that there is a risk of rear-end collision and an alarm is issued.

By combining the reaction distance with the calculated limit safety distance, the reaction time of the driver behind is taken into account, further increasing the reliability of rear-end collision assessment.

As another improvement of the vehicle rear-end collision prevention method of the present invention, in step 4, the sending out the alarm includes: sending out an alarm reminder to the vehicle behind and/or sending an alarm reminder to the driver of the own vehicle.

In order to solve the above-mentioned technical problems, a vehicle anti-rear-collision system based on the above-mentioned vehicle anti-rear-collision method of the present invention includes: an image capture device, used to obtain images of the rear vehicle; a distance measuring device, used to obtain the distance of the rear vehicle relative to the vehicle The speed measuring device is used to obtain the driving speed of the rear vehicle relative to the vehicle; the early warning module is used to issue an alarm; the deceleration acquisition device is used to obtain the braking deceleration of the vehicle; the brake pedal travel sensor is used to obtain the vehicle The stroke of the brake pedal of the car; the controller is used to, when the car brakes, according to the image of the rear car, the real-time speed of the rear car relative to the car, the real-time distance of the rear car relative to the car, and the model of the car Information, real-time braking deceleration and real-time brake pedal travel, to determine whether there is a risk of rear-end collision, and if so, an alarm will be issued, wherein the vehicle model information is pre-stored in the controller.

Further, the controller includes:

Model module: used to store the model information of the car, and also used to obtain the model information of the rear car according to the image of the rear car;

Acquisition module: used to obtain the real-time limit braking deceleration of the rear vehicle according to the vehicle model information, brake deceleration and brake pedal stroke, and the vehicle model information of the rear vehicle;

The first calculation module: used to calculate the real-time limit safety distance between the rear vehicle and the vehicle according to the driving speed of the rear vehicle relative to the vehicle and the limit braking deceleration of the vehicle behind;

Judgment module: used to judge whether there is a rear-end collision risk based on the real-time limit safety distance and the distance of the rear vehicle relative to the vehicle;

An instruction module: used to control the early warning module to issue an alarm when the judging module judges that there is a risk of rear-end collision.

In the above vehicle anti-rear collision system, when the vehicle starts to brake, through the image capture device, distance measuring device, speed measuring device installed at the rear of the vehicle, and the deceleration acquisition device and brake pedal installed on the vehicle The stroke sensor collects the real-time braking deceleration and brake pedal travel of the vehicle, as well as the real-time vehicle model information of the rear vehicle, so as to obtain the limit braking deceleration of the rear vehicle, and then calculate the limit safety according to the limit braking deceleration of the rear vehicle Distance, and then judge whether to face the risk of rear-end collision. Since the vehicle and the vehicle behind are driving under the same environmental factors such as road conditions and weather, the relationship between the actual braking deceleration of the two vehicles is related to the models of the two vehicles. The actual braking deceleration can take into account the impact of environmental factors on the braking of the rear vehicle, more accurately assess the risk of the vehicle being rear-ended, and improve the effectiveness of the alarm reminder.

Further, the acquisition module includes a storage module, a query module, a second calculation module and a third calculation module, and the storage module stores the one-to-one corresponding vehicle model coefficient information of all vehicle models; the query module is used to The vehicle type information is queried in the storage module to obtain the vehicle type coefficient; the second calculation module is used to obtain the deceleration coefficient according to the brake pedal stroke of the vehicle; , to obtain the limit braking deceleration of the rear car.

Further, the second calculating module acquires the deceleration coefficient according to the brake pedal travel of the own vehicle.

Further, the third calculation module multiplies the vehicle type coefficient by the deceleration coefficient and then multiplies the deceleration of the own vehicle to obtain the limit braking deceleration of the following vehicle.

Further, the first calculation module sets the following vehicle to perform a uniform deceleration movement from the current moment, the driving speed of the following vehicle relative to the own vehicle is the initial speed of the uniform deceleration movement, and the limit braking deceleration of the following vehicle is decelerated to calculate The distance when the vehicle behind decelerates to zero is the limit safety distance.

Further, the judgment method of the judgment module is:

Step c1: Calculate the optimal safety distance according to the limit safety distance and reaction distance;

Step c2: compare the size relationship between the optimal safety distance and the distance between the rear vehicle and the vehicle;

Step c3: If the optimal safe distance is not less than the distance between the rear vehicle and the own vehicle, it is judged that there is a risk of rear-end collision.

To sum up, using the vehicle rear-end collision prevention method and system, the ultimate braking deceleration of the rear vehicle can be obtained according to the actual deceleration derivation of the vehicle, and the influence of environmental factors on the braking of the rear vehicle can be considered, so that the vehicle can be more accurately evaluated. The risk of being rear-ended increases the effectiveness of alarm reminders.

Description of drawings

In the attached picture:

Fig. 1 is a flow chart of the vehicle rear-end collision prevention method of the present invention.

Fig. 2 is a structural block diagram of the vehicle rear-end collision prevention system of the present invention.

In the figure, 1. image capturing device; 2. distance measuring device; 3. speed measuring device; 4. early warning module; 5. deceleration acquisition device; 6. controller; 61. model module; 62. acquisition module; 622, query module; 623, second calculation module; 624, third calculation module; 63, first calculation module; 64, judgment module; 65, command module; 7, brake pedal travel sensor.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted here that the descriptions of these embodiments are used to help understand the present invention, but are not intended to limit the present invention.

Fig. 1 shows a method for preventing rear-end collision of a vehicle according to the present invention. As shown in Figure 1, the vehicle rear-end collision prevention method includes the following steps:

Step S10: When the vehicle brakes, obtain the braking deceleration and the brake pedal stroke of the vehicle in real time, and obtain the model information of the vehicle behind, the speed relative to the vehicle and the distance to the vehicle in real time.

When the vehicle starts to brake, real-time collection starts, that is, continuous collection, real-time collection of braking deceleration information and brake pedal stroke information, and at the same time collects vehicle model information, relative speed of the vehicle and relative vehicle information. The distance of the car continues until the car stops braking. According to the corresponding data at each collection time, it is judged whether there is a risk of rear-end collision, and a dynamic and efficient alarm is issued. The period interval of real-time acquisition can be 1-3s.

The braking deceleration of the vehicle is a comprehensive braking coefficient including road friction, wind resistance and so on. Different weather: In sunny and rainy weather, the braking performance of vehicles on the same road is different; in the same weather environment, on different roads, due to the different road adhesion, the braking performance of the same vehicle is also different. Therefore, relative to the own vehicle and the following vehicle under the same weather and road environment, the actual deceleration value of the own vehicle has reference significance for the calculation of the actual deceleration value of the following vehicle.

Step S20: If the driving speed of the following vehicle relative to the own vehicle is less than zero, then end the method; otherwise, according to the model information of the own vehicle, real-time braking deceleration and brake pedal travel, and the vehicle model information of the following vehicle, obtain the following vehicle The limit braking deceleration.

When the real-time speed of the vehicle behind is lower than that of the vehicle in front, it can be directly judged that if the two vehicles maintain the current speed, there is no risk of rear-end collision, so there is no risk of rear-end collision at the current moment, and this method can be ended; when the real-time speed of the vehicle behind is equal to the vehicle in front , although if the two vehicles maintain the current speed, they will not face the risk of rear-end collision, but because the vehicle is in the braking state, there is also a certain risk at the current moment, so it is the same as when the real-time speed of the vehicle behind is greater than that of the vehicle in front. follow-up judgment.

Optionally, the methods for obtaining the limit braking deceleration of the following vehicle include:

Step a1: Obtain the vehicle model coefficient according to the vehicle model information of the own vehicle and the vehicle model information of the following vehicle. The specific method may be as follows: according to the vehicle model information of the own vehicle and the vehicle model information of the following vehicle, the vehicle model coefficient is obtained by consulting the data set, wherein the data set stores the vehicle model coefficient information corresponding to each vehicle model. The car model coefficient is related to the models of the front car and the rear car. After the car model identification of the rear car is completed, the corresponding car model coefficient can be extracted from the pre-set and stored car model coefficient data set.

Optionally, the vehicle model coefficient can be obtained according to the calibration. Various vehicle models are calibrated under the same road and weather environmental conditions to obtain the relationship between the actual braking deceleration of the two, and store it in the vehicle for recall.

Vehicle type refers to the type of vehicle, and the above method is more time-consuming and labor-intensive due to the many types of vehicles on the market, and the test is relatively complicated. Since the vehicle must meet the national automobile braking distance standard when it is on the road, it can be considered that the design braking deceleration of various types of vehicles must not be less than a set value, that is, the minimum design braking deceleration. Of course, the larger the design braking deceleration value is, the better, but due to cost, vehicle structure and other factors, each vehicle manufacturer will not deviate the design braking deceleration design from the set value too much, so it can be determined according to the national standard. Car braking distance is divided into vehicle types.

National standards GB12676 and GB/T13594 stipulate that the braking distance standard for cars is as follows: (1) For passenger cars with no more than nine seats, when the initial speed is 50Km/h, it shall not exceed 19m;

(2) For other vehicles whose total mass does not exceed 4.5t, when the initial speed is 50Km/h, the maximum speed shall not exceed 21m;

(3) For other vehicles, when the initial speed is 30Km/h, it shall not exceed 9m.

According to the three provisions in the national automobile braking distance standard, all vehicle types are divided into three types: the first type of vehicles, the second type of vehicles and the third type of vehicles. The corresponding relationship is as follows:

Class I vehicle: a passenger vehicle with no more than nine seats, the braking distance shall not exceed 19m when the initial speed is 50Km/h;

The second category of vehicles: except for the first category of vehicles, other vehicles whose total mass does not exceed 4.5t, when the initial speed is 50Km/h, the braking distance does not exceed 21m;

The third category of vehicles: except for the vehicles of the first category and the second category, when the initial speed is 30Km/h, the braking distance shall not exceed 9m.

Braking distance is one of the key parameters to measure the braking performance of a car. It means the distance traveled by the vehicle from the start of braking to when the car is completely stationary when the vehicle is at a certain speed .

According to the division of the above-mentioned first-class cars, second-class cars and third-class cars, the corresponding car model coefficients can be obtained through simulation, and the recommended values of the car model coefficients are given in Table 1. value.

Table 1 Vehicle model coefficient data set

Step a2: Obtain the deceleration coefficient according to the brake pedal travel of the vehicle. Specifically include:

① Obtain the theoretical braking deceleration value of the vehicle according to the brake pedal stroke of the vehicle and the pedal stroke-deceleration relationship curve of the vehicle. The pedal stroke-deceleration relationship curve of the vehicle can be directly obtained according to the parameter information of the vehicle, and then the deceleration corresponding to the current real-time brake pedal stroke is searched on the curve, which is the real-time theoretical braking deceleration value.

② Obtain the maximum braking deceleration value of the vehicle. The maximum braking deceleration is the design parameter of the vehicle, which can be obtained directly according to the parameter information of the vehicle, or obtained from the pedal stroke-deceleration relationship curve.

③ Obtain the deceleration coefficient according to the real-time theoretical braking deceleration value of the vehicle. The quotient obtained by dividing the maximum braking deceleration value by the real-time theoretical braking deceleration value can be used as the real-time deceleration coefficient.

Step a3: According to the vehicle model coefficient, the deceleration coefficient and the braking deceleration of the own vehicle, obtain the limit braking deceleration of the following vehicle. Optionally, multiply the vehicle model coefficient by the deceleration coefficient and then multiply by the deceleration of the vehicle to obtain the ultimate braking deceleration of the following vehicle:

Assuming that the vehicle type coefficient is β, the deceleration coefficient is μ, and the real-time deceleration of the vehicle is b, then the calculation formula of the real-time braking deceleration a of the following vehicle is: a=μβ*b.

Step S30: Calculate the limit safety distance between the following vehicle and the own vehicle according to the driving speed of the following vehicle relative to the own vehicle and the limit braking deceleration of the following vehicle.

Optionally, according to the uniform deceleration formula, it is set that the rear vehicle will perform uniform deceleration from the current moment, the driving speed of the subsequent vehicle relative to the own vehicle is the initial speed of the uniform deceleration motion, and the ultimate braking deceleration of the subsequent vehicle is decelerated, and the calculation The distance when the vehicle behind decelerates to zero is the limit safety distance.

Step S40: According to the limit safety distance and the distance of the following vehicle relative to the own vehicle, it is judged whether there is a risk of rear-end collision, and if so, an alarm is issued. The specific process can be:

Step b1: Calculate the optimal safety distance according to the limit safety distance and the reaction distance. Optionally, assuming that the optimal safety distance is L, the reaction distance is D, and the limit safety distance is S, then: L=S+D. Among them, the reaction distance refers to the distance traveled by the vehicle within the driver's reaction time. In theory, the value of D is the product of the speed of the vehicle behind and the reaction time. The speed of the vehicle can be calculated and obtained according to the relative speed of the vehicle behind and the speed measurement of the vehicle. The reaction time range can be [0, n], but usually the maximum value n is used to ensure safety. The setting method of the response time n can be uniformly set to a fixed value, such as 4s. The value of n should not be too large, which will easily lead to excessive warning, and the value of n should not be too small, which will easily cause the warning to lag or not be adequately activated. Reduce the harm caused by rear-end collision accidents. The dynamic value can also be designed in combination with the vehicle type of the rear vehicle. When the vehicle behind is the first type vehicle, the second type vehicle and the third type vehicle in sequence, the value of the reaction time increases sequentially. For example, when the vehicle behind is of the first category, n=2s; when the vehicle behind is of the third category, n=4s.

Step b2: Compare the relationship between the optimum safety distance and the distance between the following vehicle and the own vehicle.

Step b3: If the optimal safe distance is not less than the distance between the following vehicle and the own vehicle, it is judged that there is a risk of rear-end collision and an alarm is issued. When the distance between the rear vehicle and the front vehicle is less than the optimal safety distance L, the vehicle will send out an alarm.

Optionally, the sending out of the alarm includes: sending out an alarm reminder to the car behind, which can be by sending out light or honking the horn of the car backwards; Image, text display, or voice alarm prompt.

Fig. 2 shows a vehicle rear-end collision prevention system of the present invention. As shown in FIG. 2 , the system includes: an image capturing device 1 , a distance measuring device 2 , a speed measuring device 3 , an early warning module 4 , a deceleration acquisition device 5 , a controller 6 and a brake pedal stroke sensor 7 .

The image capturing device 1 is used to acquire the image of the rear vehicle. Can adopt video camera, be installed in this car rear end, take pictures and obtain photos.

The distance measuring device 2 is used to obtain the distance of the following vehicle relative to the own vehicle. The laser radar can be used for distance measurement, or a binocular camera can be used for distance measurement installed at the rear of the vehicle. Optionally, the image capturing device 1 and the distance measuring device 2 can be realized by using the same image capturing module to reduce costs.

The speed measuring device 3 is used to obtain the traveling speed of the following vehicle relative to the own vehicle. The vehicle speed device is also installed at the rear of the vehicle, and the vehicle speed of the rear vehicle is measured, which is the speed of the rear vehicle relative to the vehicle. A radar speedometer or the like can be used, or a radar system can be shared with the distance measuring device 2 .

The early warning module 4 is used for issuing an alarm. As an executive component, send an alarm reminder to the car behind, which can be by the car emitting light backwards, honking the whistle, etc.; and/or send an alarm reminder to the driver of the car, which can be displayed on the central control screen of the car by images or text. Or voice alarm prompt.

The deceleration acquisition device 5 is used to acquire the braking deceleration of the own vehicle. The deceleration sensor can be directly installed on the vehicle to obtain the real-time deceleration value of the vehicle.

The brake pedal stroke sensor 7 is used to obtain the brake pedal stroke of the vehicle.

The controller 6 is used for braking the vehicle according to the image of the rear vehicle, the real-time traveling speed of the rear vehicle relative to the vehicle, the real-time distance of the rear vehicle relative to the vehicle, the model information of the vehicle, and real-time braking. Deceleration and real-time brake pedal travel, judge whether to face the risk of rear-end collision, if then send an alarm, wherein, the model information of this car is stored in the controller 6 in advance.

Optionally, the controller 6 includes a model module 61 , an acquisition module 62 , a first calculation module 63 , a judgment module 64 and an instruction module 65 .

Model module 61: used to store the model information of the own vehicle, and also used to obtain the model information of the rear vehicle according to the image of the rear vehicle. The car model will not change, it can be built in the car model module 61 or manually input once. The car model module 61 uses image recognition technology to input the real-time captured image of the rear car into the pre-trained neural network model, and according to the pre-designed three types of car model conditions , to identify the type of vehicle behind.

Obtaining module 62: used to obtain the limit braking deceleration of the following vehicle according to the vehicle type information, braking deceleration and brake pedal travel of the own vehicle, and the vehicle type information of the following vehicle. Optionally, the acquisition module 62 includes a storage module 621 , a query module 622 , a second calculation module 623 and a third calculation module 624 .

The storage module 621 stores the car model coefficient information of one-to-one correspondence between the own car and all the car models of the following cars. Similar to the description in the above-mentioned vehicle rear-end collision prevention method, all vehicle models can be divided into three types according to the three regulations in the national automobile braking distance standard, and then use the simulation test to obtain the vehicle model coefficient data set as shown in Table 1, and store it in the storage module 621 for inspection. The model coefficient can be obtained according to simulation and test.

The query module 622 is used for querying and obtaining the vehicle model coefficient in the storage module 621 according to the vehicle model information of the own vehicle and the vehicle model information of the following vehicle.

The second calculation module 623 is used to obtain the deceleration coefficient according to the brake pedal stroke of the own vehicle. Optionally, first obtain the theoretical braking deceleration value of the vehicle according to the brake pedal stroke of the vehicle and the pedal stroke-deceleration relationship curve of the vehicle; then obtain the theoretical braking deceleration value of the vehicle according to the braking deceleration and the theoretical braking The deceleration value gets the deceleration factor.

The third calculation module 624 is used to obtain the limit braking deceleration of the following vehicle according to the vehicle type coefficient, the deceleration coefficient and the braking deceleration of the own vehicle. Optionally, assuming that the vehicle type coefficient is β, the deceleration coefficient is μ, and the real-time deceleration of the vehicle is b, then the calculation formula of the real-time braking deceleration a of the following vehicle is: a=μβ*b.

The first calculating module 63: used for calculating the limit safety distance between the following vehicle and the own vehicle according to the driving speed of the following vehicle relative to the own vehicle and the limit braking deceleration of the following vehicle.

Optionally, set the rear car to do uniform deceleration from the current moment. The speed of the rear car relative to the own car is the initial speed of the uniform deceleration motion. The ultimate braking deceleration of the rear car is decelerated, and the calculation of the rear car decelerates to zero The distance at this time is the limit safety distance.

Judgment module 64: for judging whether there is a risk of rear-end collision according to the limit safety distance and the distance of the following vehicle relative to the own vehicle. Optionally, the judging method of judging module 64 is:

Step c1: Calculate the optimum safety distance according to the limit safety distance and the reaction distance; set the optimum safety distance as L, the reaction distance as D, and the limit safety distance as S, then: L=S+D. The setting of the reaction distance is the same as in the above-mentioned vehicle rear-end collision prevention method, and will not be described in detail.

Step c2: compare the size relationship between the optimal safety distance and the distance between the rear vehicle and the vehicle;

Step c3: If the optimal safe distance is not less than the distance between the rear vehicle and the own vehicle, it is judged that there is a risk of rear-end collision. When the distance between the rear vehicle and the front vehicle is less than the optimal safety distance L, the vehicle will send out an alarm.

Instruction module 65: used to control the early warning module 4 to issue an alarm and send an action instruction to the early warning module 4 when the judging module 64 judges that there is a risk of rear-end collision.

During use, when this car starts to brake, through the image capture device 1, the distance measuring device 2, the speed measuring device 3 installed at the rear of this car, and the deceleration acquisition device 5 installed on this car, the brake pedal stroke Sensor 7 collects the real-time braking deceleration and brake pedal stroke of the vehicle, as well as the real-time vehicle model information of the rear vehicle, so as to obtain the limit braking deceleration of the rear vehicle, and then calculate the limit safety according to the limit braking deceleration of the rear vehicle Distance, and then judge whether to face the risk of rear-end collision. Since the vehicle and the following vehicle are driving under the same road conditions and environmental factors such as weather, the relationship between the actual braking deceleration of the two vehicles is related to the models of the two vehicles, and because the actual braking deceleration of the vehicle is integrated with the braking force , road surface friction, wind resistance and other factors, in order to obtain the actual braking deceleration of the rear car, can consider the impact of environmental factors on the rear car braking, more accurately evaluate the risk of the car being rear-end collision, and improve the effectiveness of the alarm reminder sex.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than limit the scope of protection thereof. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: Those skilled in the art can still make various changes, modifications or equivalent replacements to the specific implementation of the invention after reading the present invention, but these changes, modifications or equivalent replacements are all within the protection scope of the pending claims of the invention.

Claims (10)

1. A vehicle anti-rear-end collision method, is characterized in that, comprises the steps: Step 1: When the vehicle brakes, obtain the braking deceleration and brake pedal stroke of the vehicle in real time, and obtain the vehicle model information of the rear vehicle, the driving speed relative to the vehicle, and the distance relative to the vehicle in real time; Step 2: If the speed of the following vehicle relative to the vehicle is less than zero, then end the method; otherwise, according to the vehicle model information, brake deceleration and brake pedal travel, and the vehicle model information of the vehicle, obtain the limit of the vehicle behind braking deceleration; Step 3: According to the driving speed of the rear vehicle relative to the own vehicle, and the limit braking deceleration of the rear vehicle, calculate the limit safety distance between the rear vehicle and the own vehicle; Step 4: According to the limit safety distance and the distance of the rear vehicle relative to the own vehicle, it is judged whether there is a risk of rear-end collision, and if so, an alarm is issued. 2. A kind of vehicle anti-rear-end collision method according to claim 1, is characterized in that, in step 2, the method for obtaining the limit braking deceleration of rear car comprises: Step a1: Obtain the vehicle model coefficient according to the model information of the own car and the model information of the following car; Step a2: Obtain the deceleration coefficient according to the brake pedal travel of the vehicle; Step a3: According to the vehicle model coefficient, the deceleration coefficient and the braking deceleration of the own vehicle, obtain the limit braking deceleration of the following vehicle. 3. A vehicle rear-end collision prevention method according to claim 2, characterized in that said step a1 comprises: consulting the data set according to the vehicle model information of the own vehicle and the vehicle model information of the following vehicle to obtain the vehicle model coefficient, wherein, in the data set Stores one-to-one vehicle model coefficient information for all vehicle models. 4. A kind of vehicle rear-end collision prevention method according to claim 2, is characterized in that, described step a2 comprises: According to the brake pedal stroke of the vehicle and the pedal stroke-deceleration relationship curve of the vehicle, the theoretical braking deceleration value of the vehicle is obtained; Acquire the deceleration coefficient according to the theoretical braking deceleration value of the vehicle. 5. A vehicle rear-end collision prevention method according to any one of claim 2, characterized in that said step a3 comprises: multiplying the vehicle type coefficient by the deceleration coefficient and then multiplying the deceleration of the vehicle to obtain the limit of the vehicle behind braking deceleration. 6. A vehicle rear-end collision prevention method according to claim 1, characterized in that said step 3 comprises: setting the rear vehicle to perform a uniform deceleration movement from the current moment, and the speed of the rear vehicle relative to the vehicle is uniformly decelerated The initial speed of the movement is decelerated by the limit braking deceleration of the vehicle behind, and the distance when the vehicle behind decelerates to zero is calculated as the limit safety distance. 7. A method for preventing rear-end collision of a vehicle according to claim 1, wherein said step 4 comprises: Step b1: Calculate the optimal safety distance according to the limit safety distance and reaction distance; Step b2: compare the size relationship between the optimal safety distance and the distance between the rear vehicle and the vehicle; Step b3: If the optimal safe distance is not less than the distance between the following vehicle and the own vehicle, it is judged that there is a risk of rear-end collision and an alarm is issued. 8. A vehicle rear-end collision prevention method according to claim 1 or 7, characterized in that, in step 4, the sending out the alarm includes: sending out an alarm reminder to the vehicle behind and/or sending an alarm reminder to the driver of the own vehicle. 9. A vehicle rear-end collision prevention system, characterized in that it comprises: An image capturing device (1), used to acquire images of the rear vehicle; A distance measuring device (2), used to obtain the distance of the rear vehicle relative to the vehicle; The speed measuring device (3) is used to obtain the traveling speed of the rear vehicle relative to the vehicle; Early warning module (4), is used for sending out an alarm; A deceleration acquisition device (5), used to acquire the braking deceleration of the vehicle; A brake pedal stroke sensor (7), used to obtain the brake pedal stroke of the vehicle; The controller (6) is used for braking the vehicle according to the image of the rear vehicle, the real-time traveling speed of the rear vehicle relative to the vehicle, the real-time distance of the rear vehicle relative to the vehicle, the model information of the vehicle, and the real-time Brake deceleration and real-time brake pedal stroke, judge whether to face the risk of rear-end collision, if then send an alarm, wherein, the model information of this car is pre-stored in the controller (6). 10. A kind of vehicle anti-rear collision system according to claim 9, is characterized in that, comprises: described controller (6) comprises: Model module (61): used to store the model information of the car, and also used to obtain the model information of the rear car according to the image of the rear car; Obtaining module (62): used to obtain the limit braking deceleration of the rear vehicle according to the vehicle type information, braking deceleration and brake pedal travel of the vehicle, and the vehicle type information of the rear vehicle; The first computing module (63): used for according to the traveling speed of the rear car relative to the car, and The limit braking deceleration of the rear vehicle, calculate the limit safety distance between the rear vehicle and the vehicle; Judgment module (64): used to determine whether the risk of rear-end collision is faced according to the limit safety distance and the distance of the rear vehicle relative to the vehicle; An instruction module (65): used to control the early warning module (4) to issue an alarm when the judging module (64) judges that there is a risk of rear-end collision.

Images