Vehicle backward collision avoidance method and system

Abstract

The invention discloses a vehicle backward collision avoidance method and system, and the method comprises the steps: collecting the motion information of a vehicle and a rear target vehicle, and judging whether a collision will occur or not; if it is judged that the collision possibly occurs, calculating the time from the collision when both the rear target vehicle and the vehicle are kept in the current motion state; calculating a first time threshold value; an image of a rear target vehicle is collected, and a second time threshold value is obtained by combining the first time threshold value; the distance collision occurrence time is compared with a second time threshold value, and if the distance collision occurrence time is larger than or equal to the second time threshold value, early warning and avoiding are not conducted; if the time from the collision occurrence is smaller than a second time threshold value, when the average mass value of the general vehicles is larger than or equal to the mass of the rear target vehicle, early warning is conducted, and when the average mass value of the general vehicles is smaller than the mass of the rear target vehicle, early warning and avoiding are conducted. According to the invention, the backward collision injury to a driver can be avoided or reduced.

Description

Technical Field

[0001] The present invention relates to the field of vehicle safety, and particularly to a method and system for avoiding rear collisions of vehicles. Background Art

[0002] Being rear-ended is a common accident during driving, which often endangers the life and property safety of the driver. In the prior art, the solutions for avoiding rear collisions of vehicles are mostly collision warning schemes, and they cannot effectively reduce the harm. Therefore, there is an urgent need for a method and system for avoiding rear collisions of vehicles to reduce personnel and property losses in possible rear-end accidents. Summary of the Invention

[0003] The main object of the present invention is to provide a method and system for avoiding rear collisions of vehicles, which can avoid or reduce the collision harm suffered by the driver through warning and avoidance.

[0004] The technical solution adopted by the present invention is: a method for avoiding rear collisions of vehicles, including:

[0005] Collect the motion information of the vehicle itself and the target vehicle behind, obtain the motion trajectories of the vehicle itself and the target vehicle behind according to the motion information, and determine whether a collision will occur; the motion information includes the speeds and driving directions of the vehicle itself and the target vehicle behind; further, collect multiple frames of images of the vehicle itself and the target vehicle behind, and the collection frequency is determined by the computing power of the collection and analysis device.

[0006] If it is determined that a collision may occur, calculate the time until the collision occurs when both the target vehicle behind and the vehicle itself maintain their current motion states;

[0007] Calculate a first time threshold according to the speeds of the target vehicle behind and the vehicle itself;

[0008] Collect an image of the target vehicle behind, obtain the mass information, tire pressure information, and suspension state information of the target vehicle behind from the image, calculate the mass of the target vehicle behind according to the obtained information, and determine a second time threshold according to the mass of the target vehicle behind and the first time threshold;

[0009] Compare the time until the collision occurs with the second time threshold. If the time until the collision occurs is greater than or equal to the second time threshold, no warning and avoidance are made; if the time until the collision occurs is less than the second time threshold, compare the mass of the target vehicle behind with the preset average mass of general vehicles. When the average mass of general vehicles is greater than or equal to the mass of the target vehicle behind, a warning is made. When the average mass of general vehicles is less than the mass of the target vehicle behind, a warning and avoidance are made. Further, the average mass of general vehicles is the average value of the masses of calibrated general sedans.

[0010] According to the above technical solution, the calculation method of the time when the distance collision occurs includes: calculating the product of the difference in acceleration between the rear target vehicle and the own vehicle and the relative distance between the rear target vehicle and the own vehicle, and multiplying by two to obtain a first calculated value; adding the first calculated value to the square of the difference in speed between the rear target vehicle and the own vehicle to obtain a second calculated value; subtracting the difference in speed between the rear target vehicle and the own vehicle from the second calculated value to obtain a third calculated value; dividing the third calculated value by the difference in acceleration between the rear target vehicle and the own vehicle, and the obtained value is the time when the distance collision occurs. Further, the calculation formula for the time when the distance collision occurs is:

[0011]

[0012] wherein, v1 is the vehicle speed of the rear target vehicle, v2 is the vehicle speed of the own vehicle, and v1 > v2, a1 is the acceleration of the rear vehicle, a2 is the acceleration of the own vehicle, and S is the current distance between the own vehicle and the target vehicle.

[0013] According to the above technical solution, the calculation method of the first time threshold includes: dividing the difference in speed between the rear target vehicle and the own vehicle by the speed of the rear target vehicle to obtain a fourth calculated value; multiplying the obtained fourth calculated value plus one by the braking time of the rear target vehicle, and the obtained value is the first time threshold. Further, the calculation formula for the first time threshold is:

[0014]

[0015] wherein, the time t0 is the time required for the speed of the rear target vehicle to decrease by v1 - v2 when the rear target vehicle brakes with full force.

[0016] According to the above technical solution, the method for obtaining the braking time of the rear target vehicle includes: according to the difference in speed between the rear target vehicle and the own vehicle, looking up the table to obtain the braking time of the rear target vehicle, and the table is a pre-stored correspondence table between the time required for vehicle braking and the speed reduced by braking.

[0017] According to the above technical solution, the methods for obtaining the mass information, tire pressure information and suspension state information of the rear target vehicle include:

[0018] Identifying the size, vehicle identification type, current tire pressure and current suspension height of the rear target vehicle according to the collected image of the rear target vehicle, and searching for the vehicle matching the rear target vehicle in the database; if there is a vehicle matching the rear target vehicle in the database, extracting the unloaded mass, loaded mass, unloaded tire pressure, loaded tire pressure, unloaded suspension height and loaded suspension height of the corresponding matching vehicle; if there is no vehicle matching the rear target vehicle in the database, searching for a similar vehicle for the rear target vehicle in the database according to the size and vehicle identification type of the rear target vehicle, and extracting the unloaded mass, loaded mass, unloaded tire pressure, loaded tire pressure, unloaded suspension height and loaded suspension height of the corresponding similar vehicle.

[0019] According to the above technical solution, the method for calculating the mass of the rear target vehicle includes:

[0020] Calculate the difference between the full-load mass and the no-load mass of the rear target vehicle to obtain a fourth calculated value; respectively calculate the first exponents of the full-load suspension height and the no-load suspension height of the rear target vehicle, and then sum them to obtain a fifth calculated value; respectively calculate the first exponents of the current suspension height and the no-load suspension height of the rear target vehicle, and then take the difference to obtain a sixth calculated value; divide the fourth calculated value by the fifth calculated value, multiply the obtained value by the sixth calculated value to obtain a seventh calculated value; add the seventh calculated value to the no-load mass of the rear target vehicle to obtain an eighth calculated value; the first exponent is a preset value; further, the calculation formula for the above calculation process is:

[0021]

[0022] Respectively calculate the second exponents of the full-load tire pressure and the no-load tire pressure, and then sum them to obtain a ninth calculated value; respectively calculate the second exponents of the current tire pressure and the no-load tire pressure of the rear target vehicle, and then take the difference to obtain a tenth calculated value; divide the fourth calculated value by the ninth calculated value, multiply the obtained value by the tenth calculated value to obtain an eleventh calculated value; add the eleventh calculated value to the no-load mass of the rear target vehicle to obtain a twelfth calculated value; the second exponent is a preset value; further, the calculation formula for the above calculation process is:

[0023]

[0024] Calculate the average value of the eighth calculated value and the twelfth calculated value, which is the mass of the rear target vehicle. Further, the calculation formula for the above calculation process is:

[0025]

[0026] where, W k is the no-load mass of the rear target vehicle, W m is the full-load mass of the rear target vehicle, L2 is the full-load suspension height of the rear target vehicle, L1 is the no-load suspension height of the rear target vehicle, L3 is the current suspension height of the rear target vehicle, r is an exponent coefficient, which can be obtained by fitting and calculating according to vehicle data.

[0027] P2 is the full-load tire pressure of the rear target vehicle, P1 is the no-load tire pressure of the rear target vehicle, P3 is the current tire pressure of the rear target vehicle, s is an exponent coefficient, which can be obtained by fitting and calculating according to vehicle data.

[0028] According to the above technical solution, the method for obtaining the second time threshold includes:

[0029] If the mass of the rear target vehicle is less than the preset average mass of general vehicles, the second time threshold is equal to the first time threshold;

[0030] If the mass of the rear target vehicle is greater than or equal to the average mass of ordinary vehicles, the second time threshold is equal to the first time threshold multiplied by the mass correction coefficient; the calculation method of the mass correction coefficient includes calculating the difference between the mass of the rear target vehicle and the average mass of ordinary vehicles to obtain the thirteenth calculated value; dividing the thirteenth calculated value by a preset coefficient and then by the average mass of ordinary vehicles to obtain the fourteenth calculated value; taking the square root of the fourteenth calculated value and adding one to obtain the mass correction coefficient. Further, the calculation formula for the mass correction coefficient a is:

[0031]

[0032] Wherein, W is the mass of the rear target vehicle, W0 is the average mass of ordinary sedans, and K is a coefficient, which is obtained according to experience.

[0033] According to the above technical solution, the avoidance includes: identifying the surrounding environment. If there is no vehicle in front, controlling the vehicle to move forward a preset distance; if there is a vehicle in front and no vehicle on the side, controlling the vehicle to move laterally a preset distance; if there are vehicles in both the front and the side, controlling the vehicle to turn in the direction of the side with a larger space according to the environmental recognition result.

[0034] Another aspect of the present invention provides a vehicle rear collision avoidance system, which executes the above vehicle rear collision avoidance method and system.

[0035] Another aspect of the present invention provides a computer storage medium, which stores a computer program executable by a processor, and the computer program executes the above vehicle rear collision avoidance method.

[0036] The beneficial effects of the present invention are as follows: The present invention provides a vehicle rear collision avoidance method and system, which can monitor the motion states of the vehicle itself and the rear target vehicle and the image of the rear target vehicle in real time, combine the motion states and mass information of the vehicle itself and the rear target vehicle, analyze the collision possibility through preliminary analysis and further calculation analysis, and avoid or reduce the collision damage suffered by the driver and the vehicle through warning and controlling the vehicle, and reduce the personal and property losses in possible rear-end accidents.

[0037] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the accompanying drawings required in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0039] Figure 1 is a flowchart of a method for avoiding rearward collisions of a vehicle according to an embodiment of the present invention;

[0040] Figure 2 is a schematic diagram of the sensor layout according to an embodiment of the present invention;

[0041] Figure 3 is a schematic structural diagram of a device for avoiding rearward collisions of a vehicle according to an embodiment of the present invention;

[0042] Figure 4 is a schematic diagram of the movement trajectories of the host vehicle and a target vehicle behind according to an embodiment of the present invention. Detailed Embodiments

[0043] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] It should be noted that the diagrams provided in the embodiments of the present invention only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape and size of the components in actual implementation. The types, quantities and proportions of the components in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0045] In the present invention, it should also be noted that when terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, when terms such as "first" and "second" appear, they are only used for descriptive and distinguishing purposes and cannot be understood as indicating or implying relative importance.

[0046] Embodiment 1

[0047] This embodiment provides a method for avoiding rearward collisions of a vehicle. The process is as Figure 1 shown and includes:

[0048] S1. Collect the motion information of the host vehicle and the target vehicle behind, obtain the motion trajectories of the host vehicle and the target vehicle behind according to the motion information, and determine whether a collision will occur. The motion information includes the speeds and driving directions of the host vehicle and the target vehicle behind. In this embodiment, the speeds and driving directions of the host vehicle and the target vehicle behind are collected by a radar, and multiple frames of images of the host vehicle and the target vehicle behind are collected by a camera. The collection frequency is one frame every 40 ms to 80 ms, and the collection frequency is determined by the computing power of the collection and analysis device equipped on the vehicle. The higher the computing power of the device, the higher the collection frequency.

[0049] S2. If it is judged that a collision may occur, calculate the time to the collision when both the target vehicle behind and the host vehicle maintain their current motion states. According to the collected speeds and driving directions of the host vehicle and the target vehicle behind, calculate the motion trajectories of the host vehicle and the target vehicle behind. As Figure 4 shown, if there is an intersection on the motion trajectories of the host vehicle and the target vehicle behind, a collision may occur, and further calculate and analyze the time Δt to the collision.

[0050] Further, the calculation method of the time to the collision includes: calculating the product of the acceleration difference (a1 - a2) between the target vehicle behind and the host vehicle and the relative distance S between the target vehicle behind and the host vehicle, and multiplying by two to obtain 2(a1 - a2)S; adding 2(a1 - a2)S to the square of the speed difference (v1 - v2) between the target vehicle behind and the host vehicle 2 , to obtain (v1 - v2) 2 + 2(a1 - a2)S; subtracting the speed difference (v1 - v2) between the target vehicle behind and the host vehicle from (v1 - v2) 2 + 2(a1 - a2)S to obtain Dividing by the acceleration difference (a1 - a2) between the target vehicle behind and the host vehicle, and the obtained value is the time Δt to the collision. Further, the calculation formula of the time Δt to the collision is

[0051]

[0052] where, v1 is the vehicle speed of the target vehicle behind, v2 is the vehicle speed of the host vehicle, and v1 > v2, a1 is the acceleration of the vehicle behind, and a2 is the acceleration of the host vehicle.

[0053] S3. Calculate a first time threshold t1 according to the speeds of the target vehicle behind and the host vehicle. The calculation of the first time threshold t1 is also based on the braking time t0 of the target vehicle behind. A correspondence table of the braking time required for the vehicle and the speed reduced by braking is pre - stored, and according to the speed difference v1 - v2 between the target vehicle behind and the host vehicle, the braking time t0 of the target vehicle behind is found and obtained in the table.

[0054] Further, the calculation method of the first time threshold includes: dividing the speed difference v1 - v2 between the rear target vehicle and the host vehicle by the speed v1 of the rear target vehicle to obtain After adding by 1, multiplying by the braking time t0 of the rear target vehicle, and the obtained value is the first time threshold t1. Further, the calculation formula of the first time threshold t1 is:

[0055]

[0056] S4. Collect images of the rear target vehicle, obtain the mass information, tire pressure information, and suspension state information of the rear target vehicle from the images for calculating the mass of the rear target vehicle, and determine the second time threshold according to the mass of the rear target vehicle and the first time threshold. The mass information of the host vehicle and the rear target vehicle includes the unladen mass W k and the fully laden mass W m . The suspension state information includes the unladen suspension height L1, fully laden suspension height L2, and current suspension height L3 of the rear target vehicle. The tire pressure information includes the unladen tire pressure P1, fully laden tire pressure P2, and current tire pressure P3 of the rear target vehicle.

[0057] Among them, the unladen mass W k and the fully laden mass W m of the rear target vehicle, the unladen suspension height L1, fully laden suspension height L2, unladen tire pressure P1, and fully laden tire pressure P2 are retrieved from the database, and the current tire pressure P3 and current suspension height L3 of the rear target vehicle are obtained by analyzing the image information collected by the camera. The mass W of the rear target vehicle is calculated. The database can be connected to the network for real-time update.

[0058] Further, the method for obtaining the mass information and suspension state information of the rear target vehicle includes: identifying the size, vehicle identification type, current tire pressure P3, and current suspension height L3 of the rear target vehicle from the collected images of the rear target vehicle, and searching for a vehicle matching the rear target vehicle in the database; if there is a vehicle matching the rear target vehicle in the database, then extract the unladen mass W k and the fully laden mass W m , unladen suspension height L1, fully laden suspension height L2, unladen tire pressure P1, and fully laden tire pressure P2 of the corresponding matching vehicle; if there is no vehicle matching the rear target vehicle in the database, then search for a similar vehicle for the rear target vehicle in the database according to the size and vehicle identification type of the rear target vehicle, and extract the unladen mass W k and the fully laden mass W m , unladen suspension height L1, fully laden suspension height L2, unladen tire pressure P1, and fully laden tire pressure P2 of the corresponding similar vehicle;

[0059] Based on the current tire pressure P3 and the current suspension height L3 of the rear target vehicle, and the unladen mass W, laden mass W k , laden mass W m , unladen suspension height L1, laden suspension height L2, unladen tire pressure P1 and laden tire pressure P2 of a vehicle matching or similar to the rear target vehicle, calculate the mass W of the rear target vehicle.

[0060] The method of calculating the mass W of the rear target vehicle based on the unladen mass W k , laden mass W m , unladen suspension height L1, laden suspension height L2, unladen tire pressure P1 and laden tire pressure P2 of a vehicle matching or similar to the rear target vehicle, and the current tire pressure P3 and the current suspension height L3 of the rear target vehicle, includes:

[0061] Calculate the difference between the laden mass and the unladen mass of the rear target vehicle (W m -W k ); respectively calculate the first exponents of the laden suspension height L2 and the unladen suspension height L1 of the rear target vehicle and and then sum them up to obtain respectively calculate the first exponents of the current suspension height L3 and the unladen suspension height L1 of the rear target vehicle and and then take the difference Divide (W m -W k ) by multiply by and add the unladen mass W of the rear target vehicle k to obtain W L ; r is a preset value. Further, the calculation formula for the above calculation process is:

[0062]

[0063] Respectively calculate the second exponents of the laden tire pressure P2 and the unladen tire pressure P1 and and then sum them up to obtain respectively calculate the second exponents of the current tire pressure P3 and the unladen tire pressure P1 of the rear target vehicle and and then take the difference to obtain Divide (W m -W k ) by the obtained value is multiplied by and add the unladen mass W of the rear target vehicle k to obtain W p ; s is a preset value; further, the calculation formula for the above calculation process is:

[0064]

[0065] Calculate W L and the average value of the W p is the mass W of the target vehicle behind. Further, the calculation formula for the above calculation process is:

[0066]

[0067] where r is an exponential coefficient, which can be obtained by fitting calculation according to vehicle data, and an empirical value of 2 is taken in this embodiment. s is an exponential coefficient, which can be obtained by fitting calculation according to vehicle data, and an empirical value of 2.5 is taken in this embodiment.

[0068] Further, the method for obtaining the second time threshold t2 includes:

[0069] If the mass of the target vehicle behind is less than the average mass of ordinary vehicles, the second time threshold is equal to the first time threshold;

[0070] If the mass W of the target vehicle behind is greater than or equal to the average mass W0 of ordinary vehicles, the second time threshold t2 is equal to the first time threshold t1 multiplied by the mass correction coefficient a; the calculation method of the mass correction coefficient a includes calculating the difference between the mass W of the target vehicle behind and the average mass W0 of ordinary vehicles to obtain the thirteenth calculated value; dividing the thirteenth calculated value by the preset coefficient k and then dividing by the average mass W0 of ordinary vehicles to obtain the fourteenth calculated value; taking the square root of the fourteenth calculated value and adding 1 to obtain the mass correction coefficient a. Further, the calculation formula for the mass correction coefficient a is:

[0071]

[0072] where W is the mass of the target vehicle behind, W0 is the average mass of ordinary sedans behind, and k is a coefficient, and an empirical value of 3 is taken in this embodiment.

[0073] S5. Compare the time when the collision occurs with the second time threshold. When the time when the collision occurs is greater than or equal to the second time threshold, when the vehicle maintains its current motion state, due to the braking of the target vehicle behind, this collision can be avoided and no warning or avoidance is made. When the time when the collision occurs is less than the second time threshold, when the vehicle maintains its current motion state, at this time, the braking of the target vehicle behind is not sufficient to avoid this collision. Compare the average mass of ordinary vehicles and the mass of the target vehicle behind. If the average mass of ordinary vehicles is greater than or equal to the mass of the target vehicle behind, if a collision and rear-end collision occur, the risk coefficient of the driver is relatively low, so only a warning is made. If the average mass of ordinary vehicles is less than the mass of the target vehicle behind, if a collision and rear-end collision occur, the risk coefficient of the driver is relatively high, and the vehicle is controlled to give a warning and make an avoidance.

[0074] Further, the avoidance includes: identifying the surrounding environment. If there is no vehicle ahead, control the vehicle to move forward a preset distance to avoid collision as much as possible; if there is a vehicle ahead and no vehicle on the side, control the vehicle to move laterally a preset distance to avoid collision as much as possible; if there are vehicles both ahead and on the side, control the vehicle to turn towards the side with more space, so that the vehicle moves laterally after being hit by the target vehicle behind, avoiding the vehicle being sandwiched between the front and rear vehicles, thus seriously endangering the safety of the driver and the vehicle.

[0075] This embodiment also provides a computer-readable storage medium, such as a flash memory, a hard disk, a multimedia card, a card-type memory (e.g., SD or DX memory, etc.), a random access memory (RAM), a static random access memory (SRAM), a read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), a programmable read-only memory (PROM), a magnetic memory, a magnetic disk, an optical disk, a server, an App application store, etc. A computer program is stored thereon, and when the program is executed by a processor, corresponding functions are implemented. When the computer-readable storage medium of this embodiment is executed by a processor, the above-mentioned vehicle rear collision avoidance method is implemented.

[0076] Embodiment 2

[0077] This embodiment provides a vehicle rear collision avoidance system, which executes the vehicle rear collision avoidance method described in Embodiment 1, and the structure is as Figure 3 shown, including: a sensing module, a calculation module, a database, and a vehicle control module.

[0078] The sensing module includes a camera and a radar, which are used to collect the motion information and image information of the vehicle itself and the target vehicle behind, and transmit them to the calculation module. The position examples of the camera and radar arranged on the vehicle are as Figure 2 shown.

[0079] The database contains the unladen mass, full-load mass, unladen suspension height, full-load suspension height, unladen tire pressure, and full-load tire pressure of different vehicles, and is used to search for similar vehicles and matching vehicles for the target vehicle behind according to the image information identified by the sensing module, and retrieve the mass information of the corresponding vehicle and transmit it to the calculation module.

[0080] The calculation module is used to analyze the motion trajectories of the vehicle itself and the target vehicle behind according to the motion information and images of the vehicle itself and the target vehicle behind collected by the sensing module and the mass information of the target vehicle behind retrieved from the database, judge whether a collision is likely to occur, and calculate the mass of the target vehicle behind, the time to collision when the target vehicle behind and the vehicle itself both maintain the current motion state, the first time threshold, and the second time threshold respectively.

[0081] Furthermore, the calculation method of the parameters calculated by the calculation module has been described in the vehicle rear collision avoidance method in Embodiment 1, and will not be elaborated here.

[0082] The control module is used to control the vehicle to make a warning or avoidance behavior according to the parameters calculated by the calculation module.

[0083] Furthermore, the method for the control module to control the vehicle has been described in the vehicle rear collision avoidance method in Embodiment 1, and will not be elaborated here.

[0084] In summary, the present invention provides a vehicle rear collision avoidance method and system, which combines the motion states and mass information of the vehicle itself and the target vehicle behind, analyzes the collision possibility through preliminary analysis and further calculation analysis, and avoids or reduces the rear-end collision injuries suffered by the driver and the vehicle by means of warning and controlling the vehicle.

[0085] It should be noted that according to the needs of implementation, each step / component described in this application can be split into more steps / components, or two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0086] The sequence numbers of the steps in the above embodiments do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0087] It should be understood that those of ordinary skill in the art can make improvements or changes according to the above description, and all such improvements and changes should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for avoiding rear collisions of a vehicle, characterized in that, Including: Collect the motion information of the host vehicle and the rear target vehicle, analyze the motion trajectories of the host vehicle and the rear target vehicle according to the motion information, and determine whether a collision will occur; the motion information includes the speeds and driving directions of the host vehicle and the rear target vehicle; If it is determined that a collision may occur, calculate the time to the collision when both the rear target vehicle and the host vehicle maintain their current motion states; Calculate a first time threshold according to the speeds of the rear target vehicle and the host vehicle; Collect an image of the rear target vehicle, obtain the mass information, tire pressure information, and suspension state information of the rear target vehicle from the image, use them to calculate the mass of the rear target vehicle, and determine a second time threshold according to the mass of the rear target vehicle and the first time threshold; Compare the time to the collision with the second time threshold. If the time to the collision is greater than or equal to the second time threshold, no warning or avoidance action is taken; if the time to the collision is less than the second time threshold, compare the mass of the rear target vehicle with the preset average mass of general vehicles. When the average mass of general vehicles is greater than or equal to the mass of the rear target vehicle, a warning is issued; when the average mass of general vehicles is less than the mass of the rear target vehicle, a warning and avoidance action are taken.

2. The method for avoiding rear collisions of a vehicle according to claim 1, characterized in that, The calculation method of the time to the collision includes: calculating the product of the difference in accelerations between the rear target vehicle and the host vehicle and the relative distance between the rear target vehicle and the host vehicle, multiplying the result by two to obtain a first calculated value; adding the square of the difference in speeds between the rear target vehicle and the host vehicle to the first calculated value to obtain a second calculated value; subtracting the difference in speeds between the rear target vehicle and the host vehicle from the second calculated value to obtain a third calculated value; dividing the third calculated value by the difference in accelerations between the rear target vehicle and the host vehicle, and the obtained value is the time to the collision.

3. The method for avoiding rear collisions of a vehicle according to claim 1, characterized in that The calculation method of the first time threshold includes: dividing the difference in speeds between the rear target vehicle and the host vehicle by the speed of the rear target vehicle to obtain a fourth calculated value; multiplying the sum of the fourth calculated value and one by the braking time of the rear target vehicle, and the obtained value is the first time threshold.

4. The method for avoiding rear collisions of a vehicle according to claim 3, characterized in that, The method for obtaining the braking time of the rear target vehicle includes: according to the difference in speeds between the rear target vehicle and the host vehicle, look up the braking time of the rear target vehicle in a table, and the table is a pre-stored correspondence table between the time required for vehicle braking and the speed reduced by braking.

5. The method for avoiding rear collisions of a vehicle according to claim 1, characterized in that, The method for obtaining the mass information, tire pressure information, and suspension state information of the rear target vehicle includes: Identify the image of the rear target vehicle, obtain the size, vehicle identification type, current tire pressure, and current suspension height of the rear target vehicle, and search for a vehicle matching the rear target vehicle in the database; if there is a vehicle matching the rear target vehicle in the database, extract the unladen mass, laden mass, unladen tire pressure, laden tire pressure, unladen suspension height, and laden suspension height of the corresponding matching vehicle; if there is no vehicle matching the rear target vehicle in the database, search for a similar vehicle for the rear target vehicle in the database according to the size and vehicle identification type of the rear target vehicle, and extract the unladen mass, laden mass, unladen tire pressure, laden tire pressure, unladen suspension height, and laden suspension height of the corresponding similar vehicle.

6. The method for avoiding rear collisions of a vehicle according to claim 5, characterized in that, The method for calculating the mass of the rear target vehicle includes: Calculate the difference between the full-load mass and the empty-load mass of the rear target vehicle to obtain a fourth calculated value; respectively calculate the first exponents of the full-load suspension height and the empty-load suspension height of the rear target vehicle, and then sum them to obtain a fifth calculated value; respectively calculate the first exponents of the current suspension height and the empty-load suspension height of the rear target vehicle, and then take the difference to obtain a sixth calculated value; divide the fourth calculated value by the fifth calculated value, multiply the obtained value by the sixth calculated value to obtain a seventh calculated value; add the seventh calculated value to the empty-load mass of the rear target vehicle to obtain an eighth calculated value; the first exponent is a preset value; Respectively calculate the second exponents of the full-load tire pressure and the empty-load tire pressure, and then sum them to obtain a ninth calculated value; respectively calculate the second exponents of the current tire pressure and the empty-load tire pressure of the rear target vehicle, and then take the difference to obtain a tenth calculated value; divide the fourth calculated value by the ninth calculated value, multiply the obtained value by the tenth calculated value to obtain an eleventh calculated value; add the eleventh calculated value to the empty-load mass of the rear target vehicle to obtain a twelfth calculated value; the second exponent is a preset value; Calculate the average value of the eighth calculated value and the twelfth calculated value, which is the mass of the rear target vehicle.

7. The method for avoiding rear collisions of a vehicle according to claim 1, characterized in that, The method for determining the second time threshold includes: If the mass of the rear target vehicle is less than the preset average mass of general vehicles, the second time threshold is equal to the first time threshold; If the mass of the rear target vehicle is greater than or equal to the average mass of general vehicles, the second time threshold is equal to the first time threshold multiplied by a mass correction coefficient; the calculation method of the mass correction coefficient includes calculating the difference between the rear target vehicle and the average mass of general vehicles to obtain a thirteenth calculated value; dividing the thirteenth calculated value by a preset coefficient and then dividing by the average mass of general vehicles to obtain a fourteenth calculated value; taking the square root of the fourteenth calculated value and adding one, which is the mass correction coefficient.

8. The method for avoiding rear collisions of a vehicle according to claim 1, wherein The avoidance includes: identifying the surrounding environment. If there is no vehicle in front, control the vehicle to move forward a preset distance; if there is a vehicle in front and no vehicle on the side, control the vehicle to move laterally a preset distance; if there are vehicles in both the front and the side, control the vehicle to turn towards the side with a larger space according to the environmental recognition result.

9. A vehicle rearward collision avoidance system, characterized in that, The system executes the vehicle rearward collision avoidance method described in any one of claims 1-8.

10. A computer storage medium, characterized in that, It stores a computer program executable by a processor, and the computer program executes the vehicle rearward collision avoidance method described in any one of claims 1-8.

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