Vehicle rear-end collision prevention method and system

Abstract

The present invention discloses a method and system for preventing rear-end collision of a vehicle. The method comprises: when the vehicle brakes, the braking deceleration and brake pedal stroke of the vehicle are obtained in real time, and the vehicle model information, the driving speed relative to the vehicle and the distance relative to the vehicle of the rear vehicle are obtained in real time; if the driving speed of the rear vehicle relative to the vehicle is less than zero, the method is terminated, otherwise, according to the vehicle model information, braking deceleration and brake pedal stroke of the vehicle, and the vehicle model information of the rear vehicle, the limit braking deceleration of the rear vehicle is obtained; according to the driving speed of the rear vehicle relative to the vehicle, and the limit braking deceleration of the rear vehicle, the limit safety distance between the rear vehicle and the vehicle is calculated; according to the limit safety distance and the distance of the rear vehicle relative to the vehicle, it is judged whether there is a risk of rear-end collision, and if so, an alarm is issued. The influence of environmental factors on the braking of the rear vehicle can be considered, the risk of rear-end collision of the vehicle can be more accurately assessed, and the effectiveness of the alarm reminder can be improved.

Description

Technical Field

[0001] The present invention relates to the field of automobile control technology, and in particular to a vehicle rear-end collision prevention method and system. Background Art

[0002] Rear-end collisions often occur when the front vehicle brakes, but the rear vehicle fails to brake in time. Possible reasons include: driver distraction, inaccurate distance judgment, etc. At present, there are some on-board technologies for warning the rear vehicle on the market. For example, the specification of Chinese invention patent CN110803160A discloses a method for preventing rear-end collisions. The method first calculates the safe distance between the vehicle and the rear vehicle, and then gives a warning when the distance between the vehicle and the rear vehicle is less than the safe distance. The safe distance is obtained by calculating the speed of the rear vehicle, the reaction time, the maximum braking deceleration of the rear vehicle, etc. Since the design value of the maximum braking deceleration is generally given under good environmental conditions such as road adhesion, the existing rear-end collision possibility determination does not consider the difference between the actual braking of the rear vehicle and the theoretical maximum braking deceleration. Since the actual deceleration of the rear vehicle is not only related to its own braking performance, but also affected by environmental factors such as actual road conditions and weather conditions, the existing technology often finds it difficult to accurately assess the risk of being rear-ended by the rear vehicle. For example, in rainy and snowy weather, the road surface is slippery and the braking performance of the vehicle is limited, which may cause the warning to lag and fail to play an effective warning role. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a vehicle rear-end collision prevention method and system, which can take into account the influence 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.

[0004] In order to solve the above technical problems, a vehicle rear-end collision prevention method of the present invention comprises the following steps:

[0005] Step 1: When the vehicle brakes, the braking deceleration and brake pedal travel of the vehicle are obtained in real time, and the vehicle model information, the speed relative to the vehicle, and the distance relative to the vehicle are obtained in real time;

[0006] Step 2: If the speed of the rear vehicle relative to the vehicle is less than zero, the method is terminated; otherwise, the limit braking deceleration of the rear vehicle is obtained according to the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model information of the rear vehicle;

[0007] Step 3: Calculate the maximum safety distance between the rear vehicle and the vehicle based on the speed of the rear vehicle relative to the vehicle and the maximum braking deceleration of the rear vehicle;

[0008] Step 4: Determine whether there is a risk of rear-end collision based on the maximum safety distance and the distance of the rear vehicle relative to the vehicle. If so, issue an alarm.

[0009] In the above-mentioned vehicle rear-end collision prevention method, when the vehicle starts braking, if the rear vehicle is about to gradually approach the vehicle, the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model information of the rear vehicle, are used to obtain the limit braking deceleration of the rear vehicle, and then the limit safety distance is calculated based on the limit braking deceleration of the rear vehicle, and then it is determined whether there is a risk of rear-end collision. Since the vehicle and the rear vehicle are traveling under the same road conditions and weather and other environmental factors, the actual braking deceleration relationship between the two vehicles is related to the models of the two vehicles. Since the actual braking deceleration of the vehicle combines the braking force, road friction, wind resistance and other factors, the braking deceleration of the rear vehicle obtained by this deduction 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. The whole idea is novel and ingenious.

[0010] 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:

[0011] Step a1: Obtain the vehicle type coefficient according to the vehicle type information of the vehicle and the vehicle type information of the following vehicle;

[0012] Step a2: obtaining a deceleration coefficient according to the brake pedal travel of the vehicle;

[0013] Step a3: Obtain the limit braking deceleration of the following vehicle according to the vehicle type coefficient, deceleration coefficient and the braking deceleration of the own vehicle.

[0014] Furthermore, the step a1 includes: consulting a data set to obtain a vehicle model coefficient according to the vehicle model information of the vehicle and the vehicle model information of the following vehicle, wherein the data set stores vehicle model coefficient information corresponding to all vehicle models one by one.

[0015] Furthermore, the step a2 comprises:

[0016] According to the brake pedal travel of the vehicle and the pedal travel-deceleration relationship curve of the vehicle, the theoretical brake deceleration value of the vehicle is obtained;

[0017] The deceleration coefficient is obtained according to the braking deceleration of the vehicle and the theoretical braking deceleration value.

[0018] Furthermore, the step a3 includes: multiplying the vehicle type coefficient by the deceleration coefficient and then by the deceleration of the vehicle to obtain the limit braking deceleration of the rear vehicle.

[0019] Vehicle type refers to the category of vehicle. Preferably, all vehicle types are divided into three types according to the three provisions in the national automobile braking distance standard. This 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, thereby quickly responding.

[0020] As another improvement of the vehicle rear-end collision prevention method of the present invention, step three includes: setting the rear vehicle to perform uniform deceleration motion from the current moment, taking the speed of the rear vehicle relative to the vehicle as the initial speed of the uniform deceleration motion, decelerating at the limit braking deceleration of the rear vehicle, and calculating the distance when the rear vehicle decelerates to zero as the limit safety distance.

[0021] As another improvement of the vehicle rear-end collision prevention method of the present invention, the step 4 includes:

[0022] Step b1: Calculate the optimal safety distance according to the limit safety distance and the reaction distance, wherein the reaction distance is the product of the travel distance of the rear vehicle and the reaction time;

[0023] Step b2: Compare the optimal safety distance with the distance of the rear vehicle relative to the vehicle;

[0024] Step b3: If the optimal safety distance is not less than the distance between the rear vehicle and the vehicle, it is determined that there is a risk of rear-end collision and an alarm is issued.

[0025] By combining the reaction distance with the calculated maximum safety distance, the reaction time of the driver of the rear vehicle is taken into account, further increasing the reliability of the rear-end collision assessment.

[0026] As another improvement of the vehicle rear-end collision prevention method of the present invention, in step 4, issuing an alarm includes: issuing an alarm reminder to the following vehicle and / or issuing an alarm reminder to the driver of the vehicle.

[0027] In order to solve the above technical problems, the present invention provides a vehicle rear-end collision prevention system based on the above vehicle rear-end collision prevention method, comprising: an image shooting device, used to obtain an image of a rear vehicle; a distance measuring device, used to obtain the distance of the rear vehicle relative to the vehicle; a speed measuring device, used to obtain the driving speed of the rear vehicle relative to the vehicle; an early warning module, used to issue an alarm; a deceleration acquisition device, used to obtain the braking deceleration of the vehicle; a brake pedal travel sensor, used to obtain the brake pedal travel of the vehicle; a controller, used to determine whether there is a risk of rear-end collision when the vehicle brakes, according to the image of the rear vehicle, the real-time driving speed of the rear vehicle relative to the vehicle and the real-time distance of the rear vehicle relative to the vehicle, as well as the vehicle model information of the vehicle, the real-time braking deceleration and the real-time brake pedal travel, and if so, issue an alarm, wherein the vehicle model information of the vehicle is pre-stored in the controller.

[0028] Furthermore, the controller comprises:

[0029] Vehicle model module: used to store the vehicle model information of the vehicle, and also used to obtain the vehicle model information of the following vehicle based on the following vehicle image;

[0030] Acquisition module: used to obtain the real-time limit braking deceleration of the following vehicle based on the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model information of the following vehicle;

[0031] The first calculation module is used to calculate the real-time limit safety distance between the rear vehicle and the vehicle according to the speed of the rear vehicle relative to the vehicle and the limit braking deceleration of the rear vehicle;

[0032] Judgment module: used to judge whether there is a risk of rear-end collision based on the real-time maximum safety distance and the distance of the rear vehicle to the vehicle;

[0033] Instruction module: used to control the early warning module to issue an alarm when the judgment module determines that there is a risk of rear-end collision.

[0034] In the above vehicle rear-end collision prevention system, when the vehicle starts braking, the real-time braking deceleration and brake pedal stroke of the vehicle, as well as the real-time model information of the rear vehicle, are collected 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 stroke sensor installed on the vehicle, so as to obtain the limit braking deceleration of the rear vehicle, and then calculate the limit safety distance according to the limit braking deceleration of the rear vehicle, and then judge whether there is a risk of rear-end collision. Since the vehicle and the rear vehicle are driving under the same road conditions and weather and other environmental factors, the actual braking deceleration relationship between the two vehicles is related to the models of the two vehicles. The actual braking deceleration of the rear vehicle is derived from the actual braking deceleration of the vehicle, which can take into account the impact of environmental factors on the braking of the rear vehicle, more accurately assess the risk of rear-end collision of the vehicle, and improve the effectiveness of the alarm reminder.

[0035] Furthermore, the acquisition module includes a storage module, a query module, a second calculation module and a third calculation module. The storage module stores the vehicle model coefficient information of all vehicle models corresponding one to one; the query module is used to query and obtain the vehicle model coefficient in the storage module according to the vehicle model information of the vehicle and the vehicle model information of the rear vehicle; the second calculation module is used to obtain the deceleration coefficient according to the brake pedal stroke of the vehicle; the third calculation module obtains the limit braking deceleration of the rear vehicle according to the vehicle model coefficient, deceleration coefficient and braking deceleration of the vehicle.

[0036] Furthermore, the second calculation module obtains the deceleration coefficient according to the brake pedal travel of the vehicle.

[0037] Furthermore, the third calculation module multiplies the vehicle type coefficient by the deceleration coefficient and then by the deceleration of the vehicle to obtain the limit braking deceleration of the following vehicle.

[0038] Furthermore, the first calculation module sets the rear vehicle to perform uniform deceleration motion from the current moment, the speed of the rear vehicle relative to the vehicle is the initial speed of the uniform deceleration motion, the rear vehicle is decelerated at the limit braking deceleration, and the distance calculated when the rear vehicle decelerates to zero is the limit safety distance.

[0039] Furthermore, the judgment method of the judgment module is:

[0040] Step c1: Calculate the optimal safety distance based on the limit safety distance and the reaction distance;

[0041] Step c2: Compare the optimal safety distance with the distance of the rear vehicle relative to the vehicle;

[0042] Step c3: If the optimal safety distance is not less than the distance between the rear vehicle and the vehicle, it is determined that there is a risk of rear-end collision.

[0043] In summary, by adopting the vehicle rear-end collision prevention method and system, the limit braking deceleration of the rear vehicle is derived according to the actual deceleration of the vehicle, the influence of environmental factors on the braking of the rear vehicle can be considered, the risk of the vehicle being rear-ended can be assessed more accurately, and the effectiveness of the alarm reminder can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In the attached picture:

[0045] Figure 1 The figure is a flow chart of the vehicle rear-end collision prevention method of the present invention.

[0046] Figure 2 It is a structural block diagram of the vehicle rear-end collision prevention system of the present invention.

[0047] In the figure, 1. image capturing device; 2. distance measuring device; 3. speed measuring device; 4. warning module; 5. deceleration acquisition device; 6. controller; 61. vehicle type module; 62. acquisition module; 621. storage module; 622. query module; 623. second calculation module; 624. third calculation module; 63. first calculation module; 64. judgment module; 65. instruction module; 7. brake pedal travel sensor. DETAILED DESCRIPTION

[0048] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0049] Figure 1 A method for preventing rear-end collision of a vehicle according to the present invention is shown. Figure 1 As shown, the vehicle rear-end collision prevention method includes the following steps:

[0050] Step S10: When the vehicle brakes, the braking deceleration and brake pedal travel of the vehicle are obtained in real time, and the vehicle model information, the speed of the rear vehicle relative to the vehicle and the distance relative to the vehicle are obtained in real time.

[0051] When the vehicle starts braking, real-time data collection begins, i.e., continuous data collection. The data includes the braking deceleration information and the brake pedal travel information. At the same time, the vehicle model information, the speed of the vehicle behind, and the distance to the vehicle behind are collected. This process continues until the vehicle stops braking. Based on the corresponding data at each collection moment, the system determines whether the vehicle is facing the risk of rear-end collision and issues a dynamic and efficient alarm. The real-time data collection period can be 1-3s.

[0052] The braking deceleration of the vehicle is a comprehensive braking coefficient including road friction, wind resistance, etc. Different weather: sunny and rainy and snowy weather, the braking performance of vehicles on the same road is different; the same weather environment, the braking performance of the same vehicle on different roads is also different due to different road adhesion. Therefore, the actual deceleration value of the vehicle is a reference for the calculation of the actual deceleration value of the following vehicle, relative to the vehicle and the following vehicle under the same weather and road environment.

[0053] Step S20: If the speed of the rear vehicle relative to the vehicle is less than zero, the method ends; otherwise, the limit braking deceleration of the rear vehicle is obtained based on the vehicle model information of the vehicle, the real-time braking deceleration and brake pedal travel, and the vehicle model information of the rear vehicle.

[0054] When the real-time speed of the rear vehicle is less than that of the front vehicle, it can be directly judged that if the two vehicles maintain their current speeds, there is no risk of rear-end collision. Therefore, there is no risk of rear-end collision at the current moment and this method can be terminated; when the real-time speed of the rear vehicle is equal to that of the front vehicle, although if the two vehicles maintain their current speeds, there is no risk of rear-end collision, but because this vehicle is in a braking state, there is also a certain risk at the current moment. Therefore, the subsequent judgment is continued as when the real-time speed of the rear vehicle is greater than that of the front vehicle.

[0055] Optionally, the method for obtaining the limit braking deceleration of the following vehicle includes:

[0056] Step a1: Obtain the vehicle model coefficient according to the vehicle model information of the vehicle and the vehicle model information of the following vehicle. The specific method may be: according to the vehicle model information of the vehicle and the vehicle model information of the following vehicle, the vehicle model coefficient is obtained by consulting a data set, wherein the data set stores vehicle model coefficient information corresponding to all vehicle models. The vehicle model coefficient is related to the vehicle models of the preceding vehicle and the following vehicle. After the vehicle model of the following vehicle is identified, the corresponding vehicle model coefficient can be extracted from the pre-set and stored vehicle model coefficient data set.

[0057] Optionally, the vehicle model coefficient can be obtained based on calibration, and various vehicle models are calibrated under the same road and weather environmental conditions to obtain the relationship between the actual braking decelerations of the two, which is stored in the vehicle for future use.

[0058] Vehicle type refers to the type of vehicle. The above method is complicated and time-consuming and laborious due to the large number of vehicle types on the market. Since vehicles must meet the national automobile braking distance standards before they can be put on the road, it can be considered that the design braking deceleration of various vehicle types must not be less than a set value, namely the minimum design braking deceleration. Of course, the larger the design braking deceleration value, the better, but due to factors such as cost and the vehicle's own structure, each vehicle manufacturer will not design the design braking deceleration to deviate too much from the set value, so the vehicle types can be divided according to the automobile braking distance specified in the national standard.

[0059] The automobile braking distance standards specified in national standards GB12676 and GB / T13594 are: (1) for passenger cars with no more than nine seats, the braking distance shall not exceed 19m at an initial speed of 50km / h;

[0060] (2) For other vehicles with a total mass not exceeding 4.5 t, the speed shall not exceed 21 m when the initial speed is 50 km / h;

[0061] (3) For other vehicles, when the initial speed is 30 km / h, the distance shall not exceed 9 m.

[0062] All vehicle models are divided into three categories according to the three provisions of the national automobile braking distance standard: first-class vehicles, second-class vehicles and third-class vehicles. The corresponding relationship is:

[0063] Category I vehicles: passenger cars with no more than nine seats, with an initial speed of 50 km / h and a braking distance of no more than 19 m;

[0064] Category II vehicles: vehicles other than Category I vehicles with a total mass not exceeding 4.5t, with an initial speed of 50km / h and a braking distance not exceeding 21m;

[0065] The third category of vehicles: except for the first and second category vehicles, when the initial speed is 30Km / h, the braking distance shall not exceed 9m.

[0066] Braking distance is one of the key parameters to measure the braking performance of a car. It means the distance the vehicle travels from the beginning of braking to the complete stop when the vehicle is at a certain speed.

[0067] According to the above classification of first-category vehicles, second-category vehicles and third-category vehicles, simulation can be performed to obtain the corresponding vehicle model coefficients. The recommended values ​​of the vehicle model coefficients are given in Table 1, and the specific values ​​can be set by the user in actual use.

[0068] Table 1 Vehicle type coefficient data set

[0069]

[0070] Step a2: Obtain the deceleration coefficient according to the brake pedal travel of the vehicle. Specifically including:

[0071] ①According to the brake pedal travel of the vehicle and the pedal travel-deceleration relationship curve of the vehicle, the theoretical braking deceleration value of the vehicle is obtained. The pedal travel-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 travel is found on the curve, which is the real-time theoretical braking deceleration value.

[0072] ② Obtain the maximum braking deceleration value of the vehicle. The maximum braking deceleration is a design parameter of the vehicle. It can be directly obtained based on the vehicle parameter information or obtained from the pedal travel-deceleration relationship curve.

[0073] ③According to the real-time theoretical braking deceleration value of the vehicle, the deceleration coefficient is obtained. 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.

[0074] Step a3: According to the vehicle type coefficient, deceleration coefficient and the braking deceleration of the vehicle, the limit braking deceleration of the following vehicle is obtained. Optionally, the vehicle type coefficient is multiplied by the deceleration coefficient and then multiplied by the deceleration of the vehicle to obtain the limit braking deceleration of the following vehicle:

[0075] Assume that the vehicle type coefficient is β, the deceleration coefficient is μ, and the real-time deceleration of this vehicle is b. Then the calculation formula for the real-time braking deceleration a of the following vehicle is: a=μβ*b.

[0076] Step S30: Calculate the maximum safety distance between the rear vehicle and the vehicle according to the speed of the rear vehicle relative to the vehicle and the maximum braking deceleration of the rear vehicle.

[0077] Optionally, according to the uniform deceleration formula, the rear vehicle is set to perform uniform deceleration motion from the current moment, the speed of the rear vehicle relative to this vehicle is taken as the initial speed of the uniform deceleration motion, the rear vehicle is decelerated at its limit braking deceleration, and the distance calculated when the rear vehicle decelerates to zero is the limit safety distance.

[0078] Step S40: Based on the limit safety distance and the distance between the rear vehicle and the vehicle, determine whether there is a risk of rear-end collision, and if so, issue an alarm. The specific process may be:

[0079] Step b1: Calculate the optimal safety distance according to the limit safety distance and the reaction distance. Optionally, let the optimal safety distance be L, the reaction distance be D, and the limit safety distance be S, then: L=S+D. Among them, the reaction distance refers to the distance traveled by the vehicle within the driver's reaction time. Theoretically, the value of D is the product of the speed of the rear vehicle and the reaction time. The speed can be calculated and obtained based on the relative speed of the rear vehicle and the speed measurement of the vehicle. The reaction time range can be [0, n], but the maximum value n is usually taken to ensure safety. The setting method of the reaction time n can be uniformly set to a fixed value, such as 4s. The value of n is not easy to be too large, which may easily lead to excessive warning. The value of n is also not easy to be too small, which may easily lead to delayed warning or insufficient reduction of the harm caused by the rear-end collision. It can also be designed in combination with the model of the rear vehicle. When the rear vehicle is a first-class vehicle, a second-class vehicle, and a third-class vehicle, the value of the reaction time increases in turn. For example, when the rear vehicle is a first-class vehicle, n=2s; when the rear vehicle is a third-class vehicle, n=4s.

[0080] Step b2: Compare the optimum safety distance with the distance of the rear vehicle relative to the vehicle.

[0081] Step b3: If the optimal safety distance is not less than the distance between the rear vehicle and the vehicle, it is determined 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 issues an alarm.

[0082] Optionally, issuing an alarm includes: issuing an alarm reminder to the following vehicle, which may be by the vehicle emitting light, honking a horn, etc.; and / or issuing an alarm reminder to the driver of the vehicle, which may be by an image, text display on the central control screen of the vehicle, or a voice alarm prompt.

[0083] Figure 2 FIG. 1 shows a vehicle rear-end collision prevention system of the present invention. Figure 2 As shown, 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 travel sensor 7.

[0084] The image capturing device 1 is used to capture the image of the vehicle behind. A camera may be installed at the rear of the vehicle to capture the image.

[0085] The distance measuring device 2 is used to obtain the distance between the rear vehicle and the vehicle. A laser radar can be used for distance measurement, or a binocular camera can be used, which is installed at the rear of the vehicle for distance measurement. Optionally, the image capture device 1 and the distance measuring device 2 can be implemented using the same image capture module to reduce costs.

[0086] The speed measuring device 3 is used to obtain the speed of the rear vehicle relative to the vehicle. The speed measuring device is also installed at the rear of the vehicle to measure the speed of the rear vehicle, which is the speed of the rear vehicle relative to the vehicle. A radar speed meter can be used, or a radar system can be shared with the distance measuring device 2.

[0087] The warning module 4 is used to issue an alarm. As an execution component, it issues an alarm to the following vehicle, which may be a light or horn emitted by the vehicle behind; and / or issues an alarm to the driver of the vehicle, which may be an image or text display on the central control screen of the vehicle, or a voice alarm prompt.

[0088] The deceleration acquisition device 5 is used to acquire the braking deceleration of the vehicle. A deceleration sensor can be directly installed on the vehicle to acquire the real-time deceleration value of the vehicle.

[0089] The brake pedal travel sensor 7 is used to obtain the brake pedal travel of the vehicle.

[0090] The controller 6 is used to determine whether there is a risk of rear-end collision when the vehicle brakes, based on the image of the rear vehicle, the real-time speed of the rear vehicle relative to the vehicle, the real-time distance of the rear vehicle relative to the vehicle, the vehicle model information, the real-time braking deceleration and the real-time brake pedal travel, and to issue an alarm if so, wherein the vehicle model information is pre-stored in the controller 6.

[0091] Optionally, the controller 6 includes a vehicle type module 61 , an acquisition module 62 , a first calculation module 63 , a judgment module 64 and an instruction module 65 .

[0092] Model module 61: used to store the model information of the vehicle, and also used to obtain the model information of the rear vehicle according to the rear vehicle image. The model of the vehicle does not change, and it only needs to be built into the model module 61 or manually input once. The model module 61 uses image recognition technology to input the real-time image of the rear vehicle into the pre-trained neural network model, and distinguish the type of the rear vehicle according to the three pre-designed model conditions.

[0093] The acquisition module 62 is used to acquire the limit braking deceleration of the following vehicle according to the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model 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.

[0094] The storage module 621 stores the vehicle model coefficient information corresponding to all vehicle models of the vehicle and the following vehicle. Similar to the vehicle rear-end collision prevention method described above, all vehicle models can be divided into three types according to the three provisions in the national automobile braking distance standard, and then the vehicle model coefficient data set as shown in Table 1 is obtained by simulation test and stored in the storage module 621 for reference. The vehicle model coefficient can be obtained according to simulation and test.

[0095] The query module 622 is used to query and obtain the vehicle type coefficient in the storage module 621 according to the vehicle type information of the vehicle and the vehicle type information of the following vehicle.

[0096] The second calculation module 623 is used to obtain the deceleration coefficient according to the brake pedal stroke of the vehicle. Optionally, the theoretical braking deceleration value of the vehicle is obtained according to the brake pedal stroke of the vehicle and the pedal stroke-deceleration relationship curve of the vehicle; and then the deceleration coefficient is obtained according to the braking deceleration of the vehicle and the theoretical braking deceleration value.

[0097] 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 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, the calculation formula of the real-time braking deceleration a of the following vehicle is: a=μβ*b.

[0098] The first calculation module 63 is used to calculate the maximum safety distance between the rear vehicle and the vehicle according to the speed of the rear vehicle relative to the vehicle and the maximum braking deceleration of the rear vehicle.

[0099] Optionally, set the rear vehicle to perform uniform deceleration motion from the current moment, take the speed of the rear vehicle relative to this vehicle as the initial speed of the uniform deceleration motion, decelerate at the limit braking deceleration of the rear vehicle, and calculate the distance when the rear vehicle decelerates to zero as the limit safety distance.

[0100] The judgment module 64 is used to judge whether there is a risk of rear-end collision based on the limit safety distance and the distance between the rear vehicle and the vehicle. Optionally, the judgment module 64 has the following judgment method:

[0101] Step c1: Calculate the optimal safety distance according to the limit safety distance and the reaction distance; suppose the optimal safety distance is L, the reaction distance is D, and the limit safety distance is S, then: L = S + D. The setting of the reaction distance is the same as in the above vehicle rear-end collision prevention method, and will not be described in detail.

[0102] Step c2: Compare the optimal safety distance with the distance of the rear vehicle relative to the vehicle;

[0103] Step c3: If the optimal safety distance is not less than the distance between the rear vehicle and the vehicle, it is determined 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 issues an alarm.

[0104] The instruction module 65 is 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 judgment module 64 determines that there is a risk of rear-end collision.

[0105] When in use, when the vehicle starts braking, the real-time braking deceleration and brake pedal stroke of the vehicle, as well as the real-time model information of the rear vehicle, are collected through the image capture device 1, the distance measuring device 2, the speed measuring device 3 installed at the rear of the vehicle, and the deceleration acquisition device 5 and the brake pedal stroke sensor 7 installed on the vehicle, so as to obtain the limit braking deceleration of the rear vehicle, and then calculate the limit safety distance according to the limit braking deceleration of the rear vehicle, and then judge whether there is a risk of rear-end collision. Since the vehicle and the rear vehicle are driving under the same road conditions and weather and other environmental factors, the actual braking deceleration relationship between the two vehicles is related to the models of the two vehicles. Since the actual braking deceleration of the vehicle combines the braking force, road friction, wind resistance and other factors, the actual braking deceleration of the rear vehicle is derived and obtained, which can take into account the impact of environmental factors on the braking of the rear vehicle, more accurately assess the risk of rear-end collision of the vehicle, and improve the effectiveness of the alarm reminder.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

Claims

1. A vehicle rear-end collision prevention method, characterized in that: The steps include: Step 1: When the vehicle brakes, the braking deceleration and brake pedal travel of the vehicle are obtained in real time, and the vehicle model information, the speed relative to the vehicle, and the distance relative to the vehicle are obtained in real time; Step 2: If the speed of the rear vehicle relative to the vehicle is less than zero, the method is terminated; otherwise, the limit braking deceleration of the rear vehicle is obtained according to the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model information of the rear vehicle; Step 3: Calculate the maximum safety distance between the rear vehicle and the vehicle based on the speed of the rear vehicle relative to the vehicle and the maximum braking deceleration of the rear vehicle; Step 4: Determine whether there is a risk of rear-end collision based on the maximum safety distance and the distance of the rear vehicle to the vehicle, and issue an alarm if so; 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 vehicle model information of the vehicle and the vehicle model information of the following vehicle; Step a2: obtaining a deceleration coefficient according to the brake pedal travel of the vehicle; Step a3: Obtain the limit braking deceleration of the following vehicle according to the vehicle type coefficient, the deceleration coefficient and the braking deceleration of the vehicle; The step a2 comprises: According to the brake pedal travel of the vehicle and the pedal travel-deceleration relationship curve of the vehicle, the theoretical brake deceleration value of the vehicle is obtained; Obtaining a deceleration coefficient according to the theoretical braking deceleration value of the vehicle; The step a3 comprises: multiplying the vehicle type coefficient by the deceleration coefficient and then by the deceleration of the vehicle to obtain the limit braking deceleration of the rear 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 for the limit braking deceleration a of the rear vehicle is: a=μβ*b.

2. A vehicle rear-end collision prevention method according to claim 1, characterized in that: The step a1 comprises: according to the vehicle type information of the vehicle and the vehicle type information of the following vehicle, a vehicle type coefficient is obtained by consulting a data set, wherein the data set stores vehicle type coefficient information corresponding to all vehicle types one by one.

3. A vehicle rear-end collision prevention method according to claim 1, characterized in that: The step three includes: setting the rear vehicle to perform uniform deceleration motion from the current moment, taking the speed of the rear vehicle relative to the vehicle as the initial speed of the uniform deceleration motion, decelerating at the limit braking deceleration of the rear vehicle, and calculating the distance when the rear vehicle decelerates to zero as the limit safety distance.

4. A vehicle rear-end collision prevention method according to claim 1, characterized in that: The fourth step comprises: Step b1: Calculate the optimal safety distance according to the limit safety distance and the reaction distance; Step b2: Compare the optimal safety distance with the distance of the rear vehicle relative to the vehicle; Step b3: If the optimal safety distance is not less than the distance between the rear vehicle and the vehicle, it is determined that there is a risk of rear-end collision and an alarm is issued.

5. A vehicle rear-end collision prevention method according to claim 1 or 4, characterized in that: In step 4, issuing an alarm includes: issuing an alarm to a following vehicle and / or issuing an alarm to a driver of the vehicle.

6. A vehicle rear-end collision prevention system, based on the vehicle rear-end collision prevention method according to claim 1, characterized in that: include: An image capturing device (1) is used to capture an image of a rear vehicle; A distance measuring device (2) is used to obtain the distance between the rear vehicle and the vehicle itself; The speed measuring device (3) is used to obtain the speed of the following vehicle relative to the vehicle itself; An early warning module (4), used for issuing an alarm; A deceleration acquisition device (5), used for acquiring the braking deceleration of the vehicle; A brake pedal travel sensor (7), used to obtain the brake pedal travel of the vehicle; The controller (6) is used to determine whether there is a risk of rear-end collision when the vehicle brakes, based on the image of the rear vehicle, the real-time speed of the rear vehicle relative to the vehicle, the real-time distance of the rear vehicle relative to the vehicle, the vehicle model information, the real-time braking deceleration and the real-time brake pedal travel, and to issue an alarm if there is a risk of rear-end collision, wherein the vehicle model information is pre-stored in the controller (6).

7. The vehicle rear-end collision prevention system according to claim 6, characterized in that: include: The controller (6) comprises: Model module (61): used to store the model information of the vehicle, and also used to obtain the model information of the following vehicle based on the following vehicle image; An acquisition module (62) is used to acquire the limit braking deceleration of the following vehicle based on the vehicle model information, braking deceleration and brake pedal travel of the vehicle, as well as the vehicle model information of the following vehicle; A first calculation module (63): used to calculate the maximum safety distance between the rear vehicle and the vehicle according to the speed of the rear vehicle relative to the vehicle and the maximum braking deceleration of the rear vehicle; Judgment module (64): used to judge whether there is a risk of rear-end collision based on the maximum safety distance and the distance of the rear vehicle relative to the vehicle; Instruction module (65): used to control the warning module (4) to issue an alarm when the judgment module (64) judges that there is a risk of rear-end collision.

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