Vehicle circumferential anti-collision early warning system based on multi-sensor fusion

Abstract

The invention belongs to the technical field of automobile safety, and particularly relates to a vehicle circumferential anti-collision early warning system based on multi-sensor fusion, which comprises a controller, four millimeter-wave radars, an ultrasonic radar assembly and a laser radar. According to the ultrasonic radar anti-collision strategy part, anti-collision grade and early warning are prompted based on the distance between an obstacle and a target. According to the millimeter wave radar anti-collision strategy and the laser radar anti-collision strategy, anti-collision grades and anti-collision early warning prompts are given by adopting motion characteristics based on obstacles. The circumferential anti-collision early warning strategy part based on the max function is combined with the characteristics of an ultrasonic radar, a millimeter wave radar and a laser radar, multi-source data fusion is carried out, and final circumferential anti-collision early warning is obtained through the max function. The advantages of different detection distances of the ultrasonic radar, the millimeter wave radar and the laser radar are fully utilized to realize accurate detection of obstacles, the scheme is not influenced by factors such as weather, smog and illumination, and all-weather and large-range anti-collision early warning processing can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile safety, and in particular relates to a vehicle circumferential anti-collision warning system based on multi-sensor fusion. Background Art

[0002] With the development of social economy and the popularization of automobiles, traffic accidents (especially collision accidents) on the road occur frequently. Because the anti-collision warning system can monitor the environment around the vehicle in real time, and send warning information to the driver in the event of a possible collision with an obstacle, thereby reminding the driver to avoid it, it can effectively reduce the occurrence of traffic accidents and has become the focus of attention of domestic and foreign automobile companies. The sensors currently used in the anti-collision system include ultrasonic radar, millimeter-wave radar, laser radar, etc. However, a single sensor has great limitations. For example, due to the propagation characteristics of electromagnetic waves and the non-ideal scattering of objects, millimeter-wave radar data is often affected by clutter, noise and multipath, and there are false targets in the radar data. In addition, due to the limited perception field of view of a single sensor, the vehicle anti-collision warning function of the vehicle circumference cannot be realized. To this end, the present invention aims to utilize the advantages of multiple sensors to achieve the vehicle circumferential anti-collision function at a low cost. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The technical problem to be solved by the present invention is: in view of the defects existing in the above-mentioned technologies, how to provide a vehicle circumferential collision avoidance warning system based on multi-sensor fusion. The present invention mainly combines the characteristics of millimeter wave radar, ultrasonic radar and laser radar, makes full use of the motion characteristics of obstacles relative to the vehicle, and effectively eliminates the impact of obstacles caused by clutter and noise on vehicle collision avoidance.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a vehicle circumferential collision avoidance warning system based on multi-sensor fusion, the vehicle circumferential collision avoidance warning system comprising: a controller, four millimeter wave radars, an ultrasonic radar component and a laser radar; the four millimeter wave radars, the ultrasonic radar component and the laser radar are all connected to the controller;

[0007] The four millimeter-wave radars are arranged at the middle positions of the front, rear, left and right sides of the vehicle;

[0008] The ultrasonic radar assembly includes: a front ultrasonic radar assembly and a rear ultrasonic radar assembly; wherein the front ultrasonic radar assembly includes at least 8 ultrasonic radars, and 4, 2, and 2 ultrasonic radars are arranged respectively at the positions of the front of the vehicle, the left oblique side of the front of the vehicle, and the right oblique side of the front of the vehicle;

[0009] The laser radar is arranged on the roof;

[0010] The above-mentioned vehicle circumferential collision avoidance warning system is set up to realize obstacle detection at different detection distances in the entire circumferential range. In addition, the different advantages of the detection distances of millimeter-wave radar, ultrasonic radar and lidar are used to make fusion decisions to ensure the safety and reliability of collision avoidance.

[0011] Among them, the vehicle circumferential collision avoidance warning system makes a fusion decision, and the process of executing the circumferential collision avoidance warning involves: ultrasonic radar collision avoidance strategy, millimeter wave radar collision avoidance strategy, lidar collision avoidance strategy, and circumferential collision avoidance warning strategy based on max function.

[0012] The ultrasonic radar component is used to detect the distance between the obstacle and the vehicle, judge the anti-collision level of the vehicle and whether to set the anti-collision sign position 1.

[0013] The ultrasonic radar anti-collision strategy uses the ultrasonic radar component to detect obstacles within a range of 0.2 to 4 meters around the vehicle body; if the ultrasonic radar detects an obstacle, the anti-collision warning sign position is set to 1 and the anti-collision alarm level is set to 3.

[0014] The millimeter wave radar is used to detect targets in a wide range from near to far.

[0015] In addition, due to the propagation characteristics of electromagnetic waves and the non-ideal scattering of objects, millimeter-wave radar data is often affected by clutter, noise and multipath, and false targets exist in radar data. The existence of false targets can easily lead to false alarms, causing the driver or controller to make wrong judgments.

[0016] The millimeter-wave radar collision avoidance strategy utilizes the motion characteristics of obstacles and fully exploits the data received by the millimeter-wave radar sensor; it relies on the relative motion between the target and the vehicle itself to judge whether to set the collision avoidance flag to 1, and gives the corresponding collision avoidance level.

[0017] Among them, the millimeter-wave radar collision avoidance strategy uses the forward direction of the car as the positive direction of the y-axis and the left side of the car as the positive direction of the x-axis; when using four millimeter-wave radars to detect obstacles, when the obstacle is in a stationary state, that is, the relative speed of the obstacle is less than 0.25 meters / second, if the obstacle is 2 meters in front of the car, that is, y>2 meters and within the range of 3 meters to the left and right, that is, -3<x<3 meters, then an obstacle level 3 alarm warning is issued;

[0018] If the obstacle is in motion, that is, the relative speed of the obstacle is greater than 0.25m / s, the following working conditions can be further divided according to the state of the obstacle:

[0019] Working condition 1: If the obstacle is moving in the direction directly in front of, directly behind, directly to the left or directly to the right of the vehicle, the following four conditions are met:

[0020] ①v x >0,a x <0,v y =0,a y =0,x<0,y=0;

[0021] ②v x <0,a x >0,v y =0,a y =0,x>0,y=0;

[0022] ③v x =0,a x =0,v y >0,a y <0,x=0,y<0;

[0023] ④v x =0,a x =0,v y <0,a y >0,x=0,y>0;

[0024] Among them, v x is the speed of the car in the x-axis direction; a x is the acceleration of the car in the x-axis direction; v y is the speed of the car in the y-axis direction; a y is the acceleration of the car in the y-axis direction; x is the position of the car on the x-axis; y is the position of the car on the y-axis;

[0025] Using the uniform deceleration formula S = v in kinematics 2 / 2a Calculate the relative distance s between the obstacle and the car. If the relative distance between the obstacle and the car on the x-axis is Or the relative distance between the obstacle and the car on the y-axis Less than 0.5 meters, a level 3 alarm will occur; if or If the height is greater than 0.5m and less than 1m, a Level 2 warning will be issued; if or If the distance is greater than 1 meter and less than 2 meters, a Level 1 warning will be issued;

[0026] Condition 2: If the obstacle is moving to the left front, right front, left rear or right rear of the vehicle, the following four conditions are met:

[0027] ⑤x>0,y<0;

[0028] ⑥x<0,y>0;

[0029] ⑦x>0,y>0;

[0030] ⑧x<0,y<0;

[0031] The above four conditions are the same. For condition ⑤, the displacement formula s = v0t + 0.5at is used. 2 , calculate the time t required for the position of one axis of the obstacle to become 0 in the current coordinate system of the vehicle, and then calculate the position change of the other axis in time; for the case where the obstacle is along the x-axis, we get According to the calculated time t, calculate the distance y′ that the obstacle has traveled relative to the vehicle within time t, and use the known distance y of the obstacle relative to the vehicle and the distance the obstacle has traveled relative to the vehicle at time t to make a difference. If yy′ is less than 0.5 meters, a level 3 alarm warning will occur; if yy′ is greater than 0.5 meters and less than 1 meter, a level 2 alarm warning will occur; if yy′ is greater than 1 meter and less than 2 meters, a level 1 warning will occur.

[0032] Among them, the laser radar is located at the front of the vehicle and is used as a supplementary component for millimeter radar detection to eliminate the false detection problem caused by clutter and improve the detection accuracy of obstacles; and, using the obstacles detected by the laser radar, it is judged whether to set the anti-collision flag to 1 based on the relative movement between the target and the vehicle itself, and the corresponding anti-collision level is given.

[0033] Among them, the laser radar collision avoidance strategy uses laser radar to detect obstacles within a range of 0.4 to 50 meters;

[0034] First, data preprocessing is performed to remove invalid point clouds and obstacles in the range of 0.4 to 50 meters. Then, a slope detection algorithm based on slope is used to segment the ground and obstacles. Then, the speed measurement is calculated based on the position and time of the obstacle in two adjacent frames. Based on the position and speed information between the obstacle and the car, it is determined whether the obstacle should be processed for collision avoidance warning. The strategy of laser radar collision avoidance warning is the same as that of millimeter wave radar.

[0035] Among them, the circumferential anti-collision warning strategy based on the max function combines the anti-collision warning signs and anti-collision levels of the above-mentioned links, assuming that the anti-collision result of the millimeter-wave radar is {En h ,Level h}, the anti-collision result of the laser radar is {En j ,Level j}, the anti-collision result of ultrasonic radar is {En c ,Level c}, using the MAX function max{En h ,En j ,Enc}Solve the enable flag En, and the anti-collision level is the anti-collision level corresponding to the enable position j∈{h,j,c} of En; among them, h,j,c represent the evaluation results corresponding to millimeter wave radar, laser radar, and ultrasonic radar respectively, and then determine whether to perform anti-collision warning and the anti-collision warning level.

[0036] (III) Beneficial effects

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] The present invention makes full use of the detection range, detection distance and real-time performance of ultrasonic radar, millimeter-wave radar and lidar, and makes full use of the relative motion relationship between obstacles and vehicles, and provides a circumferential collision avoidance warning system based on multi-sensor fusion. The system makes full use of the advantages of different detection distances of ultrasonic radar, millimeter-wave radar and lidar to realize accurate detection of obstacles. The scheme is not affected by factors such as weather, smoke, and light, and can realize all-weather and large-scale collision avoidance warning processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a sensor arrangement diagram of the anti-collision warning system of the present invention;

[0040] Figure 2 It is the ultrasonic radar collision avoidance strategy diagram;

[0041] Figure 3 This is the anti-collision warning strategy diagram of the millimeter wave radar;

[0042] Figure 4 It is the LiDAR collision avoidance strategy diagram;

[0043] Figure 5 It is a multi-sensor fusion collision avoidance strategy diagram.

[0044] Figure 6 It is a schematic diagram of the principle of the technical solution of the present invention.

[0045] Among them, 1-ultrasonic radar, 2-millimeter wave radar, 3-laser radar. DETAILED DESCRIPTION

[0046] In order to make the purpose, content and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples.

[0047] In order to solve the above technical problems, the present invention provides a vehicle circumferential collision warning system based on multi-sensor fusion, such as Figure 1As shown, the vehicle circumferential collision avoidance warning system includes: a controller, four millimeter-wave radars, an ultrasonic radar component and a laser radar; the four millimeter-wave radars, the ultrasonic radar component and the laser radar are all connected to the controller;

[0048] The four millimeter-wave radars are arranged at the middle positions of the front, rear, left and right sides of the vehicle;

[0049] The ultrasonic radar assembly includes: a front ultrasonic radar assembly and a rear ultrasonic radar assembly; wherein the front ultrasonic radar assembly includes at least 8 ultrasonic radars, and 4, 2, and 2 ultrasonic radars are arranged respectively at the positions of the front of the vehicle, the left oblique side of the front of the vehicle, and the right oblique side of the front of the vehicle;

[0050] The laser radar is arranged on the roof;

[0051] The above-mentioned vehicle circumferential collision avoidance warning system is set up to realize obstacle detection at different detection distances in the entire circumferential range. In addition, the different advantages of the detection distances of millimeter-wave radar, ultrasonic radar and lidar are used to make fusion decisions to ensure the safety and reliability of collision avoidance.

[0052] Among them, Figure 2-Figure 6 As shown, the vehicle circumferential collision avoidance warning system makes a fusion decision, and the process of executing the circumferential collision avoidance warning involves: ultrasonic radar collision avoidance strategy, millimeter wave radar collision avoidance strategy, lidar collision avoidance strategy, and circumferential collision avoidance warning strategy based on max function.

[0053] The ultrasonic radar component is used to detect the distance between the obstacle and the vehicle, judge the anti-collision level of the vehicle and whether to set the anti-collision sign position 1.

[0054] Among them, Figure 2 As shown, the ultrasonic radar anti-collision strategy uses the ultrasonic radar component to detect obstacles within a range of 0.2 to 4 meters around the vehicle body; if the ultrasonic radar detects an obstacle, the anti-collision warning mark position is set to 1 and the anti-collision alarm level is set to 3.

[0055] The millimeter wave radar is used to detect targets in a wide range from near to far.

[0056] In addition, due to the propagation characteristics of electromagnetic waves and the non-ideal scattering of objects, millimeter-wave radar data is often affected by clutter, noise and multipath, and false targets exist in radar data. The existence of false targets can easily lead to false alarms, causing the driver or controller to make wrong judgments.

[0057] The millimeter-wave radar collision avoidance strategy utilizes the motion characteristics of obstacles and fully exploits the data received by the millimeter-wave radar sensor; it relies on the relative motion between the target and the vehicle itself to judge whether to set the collision avoidance flag to 1, and gives the corresponding collision avoidance level.

[0058] Among them, Figure 3 As shown, the millimeter-wave radar anti-collision strategy uses the forward direction of the car as the positive direction of the y-axis and the left side of the car as the positive direction of the x-axis; when using four millimeter-wave radars to detect obstacles, when the obstacle is in a stationary state, that is, the relative speed of the obstacle is less than 0.25 m / s, if the obstacle is 2 meters in front of the car, that is, y>2 meters and within the range of 3 meters to the left and right, that is, -3<x<3 meters, then an obstacle level 3 alarm warning is issued;

[0059] If the obstacle is in motion, that is, the relative speed of the obstacle is greater than 0.25m / s, the following working conditions can be further divided according to the state of the obstacle:

[0060] Working condition 1: If the obstacle is moving in the direction directly in front of, directly behind, directly to the left or directly to the right of the vehicle, the following four conditions are met:

[0061] ①v x >0,a x <0,v y =0,a y =0,x<0,y=0;

[0062] ②v x <0,a x >0,v y =0,a y =0,x>0,y=0;

[0063] ③v x =0,a x =0,v y >0,a y <0,x=0,y<0;

[0064] ④v x =0,a x =0,v y <0,a y >0,x=0,y>0;

[0065] Among them, v x is the speed of the car in the x-axis direction; a x is the acceleration of the car in the x-axis direction; v y is the speed of the car in the y-axis direction; a y is the acceleration of the car in the y-axis direction; x is the position of the car on the x-axis; y is the position of the car on the y-axis;

[0066] Using the uniform deceleration formula S = v in kinematics 2 / 2a Calculate the relative distance s between the obstacle and the car. If the relative distance between the obstacle and the car on the x-axis is Or the relative distance between the obstacle and the car on the y-axis Less than 0.5 meters, a level 3 alarm will occur; if or If the height is greater than 0.5m and less than 1m, a Level 2 warning will be issued; if or If the distance is greater than 1 meter and less than 2 meters, a Level 1 warning will be issued;

[0067] Condition 2: If the obstacle is moving to the left front, right front, left rear or right rear of the vehicle, the following four conditions are met:

[0068] ⑤x>0,y<0;

[0069] ⑥x<0,y>0;

[0070] ⑦x>0,y>0;

[0071] ⑧x<0,y<0;

[0072] The above four conditions are the same. For condition ⑤, the displacement formula s = v0t + 0.5at is used. 2 , calculate the time t required for the position of one axis of the obstacle to become 0 in the current coordinate system of the vehicle, and then calculate the position change of the other axis in time; for the case where the obstacle is along the x-axis, we get According to the calculated time t, calculate the distance y′ that the obstacle has traveled relative to the vehicle within time t, and use the known distance y of the obstacle relative to the vehicle and the distance the obstacle has traveled relative to the vehicle at time t to make a difference. If yy′ is less than 0.5 meters, a level 3 alarm warning will occur; if yy′ is greater than 0.5 meters and less than 1 meter, a level 2 alarm warning will occur; if yy′ is greater than 1 meter and less than 2 meters, a level 1 warning will occur.

[0073] Among them, Figure 4 As shown, the laser radar is located at the front of the vehicle and is used as a supplementary component for millimeter radar detection to eliminate the false detection problem caused by clutter and improve the detection accuracy of obstacles; and, based on the obstacles detected by the laser radar, it is judged whether to set the anti-collision flag to 1 based on the relative movement between the target and the vehicle itself, and the corresponding anti-collision level is given.

[0074] Among them, Figure 4 As shown, the laser radar collision avoidance strategy uses laser radar to detect obstacles within a range of 0.4 to 50 meters;

[0075] First, data preprocessing is performed to remove invalid point clouds and obstacles in the range of 0.4 to 50 meters. Then, a slope detection algorithm based on slope is used to segment the ground and obstacles. Then, the speed measurement is calculated based on the position and time of the obstacle in two adjacent frames. Based on the position and speed information between the obstacle and the car, it is determined whether the obstacle should be processed for collision avoidance warning. The strategy of laser radar collision avoidance warning is the same as that of millimeter wave radar.

[0076] Among them, Figure 5 As shown, the circumferential anti-collision warning strategy based on the max function combines the anti-collision warning signs and anti-collision levels of the above-mentioned links, assuming that the anti-collision result of the millimeter-wave radar is {En h ,Level h}, the anti-collision result of the laser radar is {En j ,Level j}, the anti-collision result of ultrasonic radar is {En c ,Level c}, using the MAX function max{En h ,En j ,En c}Solve the enable flag En, and the anti-collision level is the anti-collision level corresponding to the enable position j∈{h,j,c} of En; among them, h,j,c represent the evaluation results corresponding to millimeter wave radar, laser radar, and ultrasonic radar respectively, and then determine whether to perform anti-collision warning and the anti-collision warning level.

[0077] Example 1

[0078] The present invention discloses a vehicle circumferential collision avoidance warning system based on multi-sensor fusion. The specific technical solution implementation mainly includes four parts: ultrasonic radar collision avoidance strategy, millimeter wave radar collision avoidance strategy, laser radar collision avoidance strategy, and circumferential collision avoidance warning strategy based on max function:

[0079] As a further improvement of the above technical solution, the vehicle circumferential collision warning system based on multi-sensor fusion includes: ultrasonic radar collision avoidance strategy. Figure 2 As shown in FIG. 1 , this strategy uses ultrasonic radar to detect obstacles within a range of 0.2 to 4 meters around the vehicle body. If the ultrasonic radar detects an obstacle, the anti-collision warning sign position is set to 1 and the anti-collision warning level is set to 3.

[0080] As a further improvement of the above technical solution, the vehicle circumferential collision warning system based on multi-sensor fusion includes: millimeter wave radar collision avoidance strategy. Figure 3As shown in the figure, this strategy uses the vehicle's forward direction as the y-axis and the left side of the vehicle as the x-axis. When using millimeter-wave radar to detect obstacles, when the obstacle is stationary (i.e., the relative speed of the obstacle is less than 0.25 m / s), if the obstacle is 2 meters in front of the vehicle (i.e., y>2 meters) and within 3 meters to the left and right (-3<x<3 meters), a level 3 obstacle alarm warning is issued. If the obstacle is in motion (the relative speed of the obstacle is greater than 0.25 m / s), the following working conditions can be further divided according to the state of the obstacle:

[0081] (1) If the obstacle is moving in the direction directly in front of, directly behind, directly to the left, or directly to the right of the vehicle, the following four conditions are met:

[0082] ①v x >0,a x <0,v y =0,a y =0,x<0,y=0;

[0083] ②v x <0,a x >0,v y =0,a y =0,x>0,y=0;

[0084] ③v x =0,a x =0,v y >0,a y <0,x=0,y<0;

[0085] ④v x =0,a x =0,v y <0,a y >0,x=0,y>0;

[0086] Using the uniform deceleration formula S = v in kinematics 2 / 2a Calculate the relative distance between the obstacle and the car. If or Less than 0.5 meters, a level 3 alarm will occur; if or If the height is greater than 0.5m and less than 1m, a Level 2 warning will be issued; if or If the distance is greater than 1 meter and less than 2 meters, a Level 1 warning will be issued;

[0087] (2) If the obstacle is moving to the left front, right front, left rear, or right rear of the vehicle, the following four conditions are met:

[0088] ⑤x>0,y<0;

[0089] ⑥x<0,y>0;

[0090] ⑦x>0,y>0;

[0091] ⑧x<0,y<0;

[0092] The above four conditions are the same. Taking condition ⑤ as an example, using the displacement formula s=v0t+0.5at 2 , calculate the time t required for the obstacle's position along one axis to become 0 in the vehicle's current coordinate system, and then calculate the position change of the other axis in time. Taking the obstacle along the x-axis as an example, we can get According to the calculated time t, calculate the distance y′ that the obstacle has traveled relative to the vehicle within the time t, and use the known distance y of the obstacle relative to the vehicle and the distance the obstacle has traveled relative to the vehicle at time t to make a difference. If yy′ is less than 0.5 meters, a level 3 alarm warning will be issued; if yy′ is greater than 0.5 meters and less than 1 meter, a level 2 alarm warning will be issued; if yy′ is greater than 1 meter and less than 2 meters, a level 1 warning will be issued;

[0093] As a further improvement of the above technical solution, the vehicle circumferential collision warning system based on multi-sensor fusion includes: a laser radar collision warning strategy. Figure 4 As shown in the figure, this strategy uses LiDAR to detect obstacles within a range of 0.4 to 50 meters. First, data preprocessing is performed to remove invalid point clouds and obstacles within a range of 0.4 to 50 meters. Then, a slope detection algorithm based on slope is used to segment the ground and obstacles, and then the speed is calculated based on the position and time of the obstacle in two adjacent frames. The obstacle is judged whether to perform anti-collision warning processing based on the position and speed information between the obstacle and the car. The strategy of LiDAR anti-collision warning is the same as that of millimeter radar.

[0094] As a further improvement of the above technical solution, the vehicle circumferential collision avoidance warning system based on multi-sensor fusion includes: a circumferential collision avoidance warning strategy based on the max function. This strategy combines the collision avoidance warning signs and collision avoidance levels of the above-mentioned links, assuming that the collision avoidance result of the millimeter wave radar is {En h ,Level h}, the anti-collision result of the laser radar is {En j ,Level j}, the anti-collision result of ultrasonic radar is {En c ,Level c}, using the MAX function max{En h ,En j ,En cSolve the enable flag En, and the anti-collision level is the anti-collision level corresponding to the enable position j∈{h,j,c} of En. Among them, h,j,c represent the evaluation results of millimeter wave radar, laser radar, and ultrasonic radar respectively, and then give whether to perform anti-collision warning and the anti-collision warning level.

[0095] In summary, the present invention belongs to the field of automobile safety technology, and specifically relates to a vehicle circumferential collision avoidance warning system based on multi-sensor fusion, including: a controller, four millimeter-wave radars, an ultrasonic radar component and a laser radar. Among them, the ultrasonic radar collision avoidance strategy partly provides collision avoidance level and warning prompts based on the distance between the obstacle and the target; the millimeter-wave radar collision avoidance strategy and the laser radar collision avoidance strategy use the motion characteristics of the obstacle to give the collision avoidance level and collision avoidance warning prompts. The circumferential collision avoidance warning strategy based on the max function combines the characteristics of ultrasonic radar, millimeter-wave radar and laser radar, performs multi-source data fusion, and uses the max function to obtain the final circumferential collision avoidance warning. The present invention makes full use of the advantages of different detection distances of ultrasonic radar, millimeter-wave radar and laser radar to achieve accurate detection of obstacles. The scheme is not affected by factors such as weather, smoke, and light, and can achieve all-weather and large-scale collision avoidance warning processing.

[0096] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A vehicle circumferential collision warning system based on multi-sensor fusion, characterized in that: The vehicle circumferential collision avoidance warning system comprises: a controller, four millimeter wave radars, an ultrasonic radar component and a laser radar; the four millimeter wave radars, the ultrasonic radar component and the laser radar are all connected to the controller; The four millimeter-wave radars are arranged at the middle positions of the front, rear, left and right sides of the vehicle; The ultrasonic radar assembly includes: a front ultrasonic radar assembly and a rear ultrasonic radar assembly; wherein the front ultrasonic radar assembly includes at least 8 ultrasonic radars, and 4, 2, and 2 ultrasonic radars are arranged respectively at the positions of the front of the vehicle, the left oblique side of the front of the vehicle, and the right oblique side of the front of the vehicle; The laser radar is arranged on the roof; The above-mentioned vehicle circumferential collision avoidance warning system is set up to realize obstacle detection at different detection distances in the entire circumferential range. In addition, the different advantages of the detection distances of millimeter-wave radar, ultrasonic radar and lidar are used to make fusion decisions to ensure the safety and reliability of collision avoidance.

2. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 1, characterized in that: The vehicle circumferential collision avoidance warning system makes a fusion decision, and the process of executing the circumferential collision avoidance warning involves: ultrasonic radar collision avoidance strategy, millimeter wave radar collision avoidance strategy, lidar collision avoidance strategy, and circumferential collision avoidance warning strategy based on max function.

3. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 2, characterized in that: The ultrasonic radar component is used to detect the distance between the obstacle and the vehicle, judge the anti-collision level of the vehicle and whether to set the anti-collision mark position 1.

4. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 3, characterized in that: The ultrasonic radar anti-collision strategy uses the ultrasonic radar component to detect obstacles within a range of 0.2 to 4 meters around the vehicle body; if the ultrasonic radar detects an obstacle, the anti-collision warning mark position is set to 1 and the anti-collision alarm level is set to 3.

5. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 4, characterized in that: The millimeter wave radar is used to detect targets in a wide range from near to far; In addition, due to the propagation characteristics of electromagnetic waves and the non-ideal scattering of objects, millimeter-wave radar data is often affected by clutter, noise and multipath, and false targets exist in radar data. The existence of false targets can easily lead to false alarms, causing the driver or controller to make wrong judgments. The millimeter wave radar collision avoidance strategy utilizes the motion characteristics of obstacles and fully exploits the data received by the millimeter wave radar sensor; The relative motion between the target and the vehicle itself is used to determine whether to set the anti-collision flag to 1 and to give the corresponding anti-collision level.

6. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 5, characterized in that: The millimeter-wave radar collision avoidance strategy uses the vehicle's forward direction as the positive direction of the y-axis and the left side of the vehicle as the positive direction of the x-axis. When using four millimeter-wave radars to detect obstacles, when the obstacle is stationary, that is, the relative speed of the obstacle is less than 0.25 m / s, if the obstacle is 2 meters in front of the vehicle, that is, y>2 meters and within the range of 3 meters to the left and right, that is, -3<x<3 meters, then an obstacle level 3 alarm warning is issued; If the obstacle is in motion, that is, the relative speed of the obstacle is greater than 0.25m / s, the following working conditions can be further divided according to the state of the obstacle: Working condition 1: If the obstacle is moving in the direction directly in front of, directly behind, directly to the left or directly to the right of the vehicle, the following four conditions are met: 1v x >0,a x <0.v y =0,a y =0,x<0,y=0; 2v x <0,a x >0,v y =0,a y =0,x>0,y=0; ③v x =0,a x =0,v y >0,a y <0,x=0,y<0; 4v x =0,a x =0,v y <0,a y >0,x=0,y>0; Among them, v x is the speed of the car in the x-axis direction; a x is the acceleration of the car in the x-axis direction; v y is the speed of the car in the y-axis direction; a y is the acceleration of the car in the y-axis direction; x is the position of the car on the x-axis; y is the position of the car on the y-axis; Using the uniform deceleration formula S = v in kinematics 2 / 2a Calculate the relative distance s between the obstacle and the car. If the relative distance between the obstacle and the car on the x-axis is Or the relative distance between the obstacle and the car on the y-axis Less than 0.5 meters, a level 3 alarm will occur; if or If the height is greater than 0.5m and less than 1m, a Level 2 warning will be issued; if or If the distance is greater than 1 meter and less than 2 meters, a Level 1 warning will be issued; Condition 2: If the obstacle is moving to the left front, right front, left rear or right rear of the vehicle, the following four conditions are met: ⑤x>0,y<0; ⑥x<0,y>0; ⑦x>0,y>0; ⑧x<0,y<0; The above four conditions are the same. For condition ⑤, the displacement formula s = v0t + 0.5at is used. 2 , calculate the time t required for the position of one axis of the obstacle to become 0 in the current coordinate system of the vehicle, and then calculate the position change of the other axis in time; for the case where the obstacle is along the x-axis, we get According to the calculated time t, calculate the distance y′ that the obstacle has traveled relative to the vehicle within time t, and use the known distance y of the obstacle relative to the vehicle and the distance the obstacle has traveled relative to the vehicle at time t to make a difference. If yy′ is less than 0.5 meters, a level 3 alarm warning will occur; if yy′ is greater than 0.5 meters and less than 1 meter, a level 2 alarm warning will occur; if yy′ is greater than 1 meter and less than 2 meters, a level 1 warning will occur.

7. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 6, characterized in that: The laser radar is located at the front of the vehicle and is used as a supplementary component for millimeter radar detection to eliminate the problem of false detection caused by clutter and improve the accuracy of obstacle detection; In addition, based on the obstacles detected by the laser radar, it is judged whether to set the anti-collision flag to 1 according to the relative movement between the target and the vehicle itself, and the corresponding anti-collision level is given.

8. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 7, characterized in that: The laser radar collision avoidance strategy uses laser radar to detect obstacles in the range of 0.4 to 50 meters; First, data preprocessing is performed to remove invalid point clouds and obstacles in the range of 0.4 to 50 meters. Then, a slope detection algorithm based on slope is used to segment the ground and obstacles. Then, the speed measurement is calculated based on the position and time of the obstacle in two adjacent frames. Based on the position and speed information between the obstacle and the car, it is determined whether the obstacle should be processed for collision avoidance warning. The strategy of laser radar collision avoidance warning is the same as that of millimeter wave radar.

9. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 8, characterized in that: The circumferential anti-collision warning strategy based on the max function combines the anti-collision warning signs and anti-collision levels of the above-mentioned links, assuming that the anti-collision result of the millimeter-wave radar is {En h ,Level h }, the anti-collision result of the laser radar is {En j ,Level j }, the anti-collision result of ultrasonic radar is {En c ,Level c }, using the MAX function max{En h ,En j ,En c }Solve the enable flag En, and the anti-collision level is the anti-collision level corresponding to the enable position j∈{h,j,c} of En; among them, h,j,c represent the evaluation results corresponding to millimeter wave radar, laser radar, and ultrasonic radar respectively, and then determine whether to perform anti-collision warning and the anti-collision warning level.

10. The vehicle circumferential collision avoidance warning system based on multi-sensor fusion as claimed in claim 9, characterized in that: The system makes full use of the detection range, detection distance and real-time performance of ultrasonic radar, millimeter-wave radar and lidar, makes full use of the relative motion relationship between obstacles and vehicles, and makes full use of the advantages of different detection distances of ultrasonic radar, millimeter-wave radar and lidar to achieve accurate detection of obstacles. The system is not affected by weather, smoke, light and other factors, and can realize all-weather and large-scale anti-collision warning processing.

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