A dynamic prediction and warning method for the swept area of ​​right-turning vehicles at an intersection

Abstract

The present invention discloses a method for dynamically predicting and warning a right-turning vehicle's travel swept area at an intersection, and relates to the technical field of traffic safety management, comprising: obtaining geometric parameters of an intersection and the type of a vehicle that is about to turn right, and capturing the right-turning vehicle's own parameters and motion parameters; establishing a model of the right-turning vehicle's travel swept area, and predicting the right-turning vehicle's travel swept area that has just entered the intersection, and projecting the predicted right-turning vehicle's travel swept area onto the ground; establishing an iterative model of the right-turning vehicle's travel swept area, iterating the right-turning vehicle's travel swept area based on real-time captured right-turning vehicle motion parameters, and projecting the iterated right-turning vehicle's travel swept area onto the ground in real time; combining the use of empirical radius values ​​to predict the right-turning vehicle's travel swept area with the real-time iterative right-turning vehicle travel swept area, so as to more realistically and reliably predict the right-turning vehicle's travel swept area.

Description

Technical field:

[0001] The present invention relates to the technical field of traffic safety management, and in particular to a method for dynamically predicting and warning a swept area of ​​a right-turning vehicle at an intersection. Background technology:

[0002] With the rapid growth of road mileage and vehicle ownership in my country, road intersections are numerous and complex, traffic composition is complex, traffic accidents are frequent, and safety issues are prominent. Right-turning vehicles at intersections are generally not controlled by signals, and the turning radius of the front and rear wheels of right-turning vehicles is different. The difference in trajectory will form an inner wheel difference similar to a crescent, resulting in a visual blind spot, which is very likely to conflict with traffic participants in other directions. In addition, right-turning vehicles and traffic participants lack cognition and awareness of this dangerous area, further exacerbating the probability of traffic accidents. As the trajectory of right-turning vehicles changes, the dangerous area caused by the inner wheel difference changes dynamically. Therefore, studying the dynamic sweep area prediction and dangerous area monitoring and early warning methods involving right-turning vehicles is the key to reducing traffic accidents at such intersections.

[0003] For example, Southeast University provides a method for determining the sweeping path of large vehicles turning at intersections, which includes: determining the applicable intersection type and design vehicle; establishing a calculation model of the inner wheel difference based on the fundamental cause of the inner wheel difference; establishing the driving trajectory equation of the rear wheels of the vehicle by assuming the motion trajectory of the front wheels of the vehicle, and visualizing the driving trajectory of the vehicle; determining the limit inner wheel difference by setting basic parameter values, fitting the driving trajectory of the optimized design vehicle model, and determining the sweeping path of large vehicles turning at intersections. This invention can be used to improve the attention of traffic participants, warn pedestrians and non-motorized vehicles, and thus achieve the purpose of reducing such traffic accidents.

[0004] In addition, Nanjing University of Technology has disclosed a method for determining the range of the inner wheel difference area for right turns at intersections for large vehicles and its application, which involves the field of traffic management and control technology, including determining the adaptability of intersections and vehicle types; constructing an inner wheel difference calculation model based on the determined intersections and vehicle types, based on the geometric characteristics of the vehicle's motion trajectory and the relationship between the vehicle's right turn angle and the aspect ratio of the right turn area at the intersection entrance; by writing an auxiliary program to calculate the inner wheel difference model, the continuous driving trajectory coordinates of the front inner wheel and the rear inner wheel of the large vehicle when turning right at the intersection are obtained, and the range of the inner wheel difference area for right turns at the intersection for large vehicles is obtained. The technical bottleneck of the existing inner wheel difference model in engineering applications is overcome, and continuous coordinate values ​​of the inner wheel difference area boundary can be provided for intersections of different geometric sizes.

[0005] Current vehicle right-turn trajectory calculation methods are mostly limited to static simulation environments, where most of the vehicle's driving conditions and trajectories are given in advance and cannot fit the dynamic and random actual driving conditions. In addition, the feedback technologies used for blind spot monitoring and early warning are mostly relatively simple, making it difficult to convey blind spot hazard information to the driver and other traffic participants outside the vehicle in real time, and there are certain limitations in practical applications.

[0006] Based on this, the present invention aims to provide a method for dynamically predicting and warning the swept area of ​​right-turning vehicles at intersections, so as to solve the problem that the swept area of ​​right-turning vehicles predicted in the prior art cannot fit the dynamic and random actual driving conditions. Summary of the invention:

[0007] In order to make up for the shortcomings of the prior art problems, the purpose of the present invention is to provide a method for dynamically predicting and warning the swept area of ​​right-turning vehicles at an intersection. By predicting the swept area model of right-turning vehicles and the iterative model of the swept area of ​​right-turning vehicles, the swept area of ​​vehicles about to turn right can be predicted according to historical parameters, and the initial reminder can be made. The swept area of ​​right-turning vehicles can be iteratively corrected according to motion parameters such as the actual trajectory, vehicle speed, inner front wheel deflection angle, etc. of the vehicle during the right turn, so that the prediction structure is more accurate and reliable, and more in line with the actual dynamic and random driving conditions.

[0008] The technical solution of the present invention is as follows:

[0009] A method for dynamically predicting and warning the area swept by right-turning vehicles at an intersection, comprising the following steps:

[0010] (1) Establishing an information acquisition system at a road intersection, wherein the intersection includes a right-turn orthogonal cross intersection, a T-intersection, and a staggered intersection, for capturing the type of vehicle about to turn right, the vehicle's own parameters, and motion parameters, wherein the type of right-turn vehicle is divided into rigid integrated vehicles and trailer vehicles;

[0011] (2) Collect historical videos of right-turning vehicles at the intersection, process the video information, obtain empirical radius values ​​of the front wheels at each stage of the rigid integrated vehicle and the trailer vehicle tractor, and obtain the geometric parameters of the road at the intersection;

[0012] (3) It is stipulated that when the inner rear wheels of the rigid integrated vehicle and the inner rear wheels of the truck trailer reach the stop line, the driver starts to turn right. In order to be close to the actual driving situation of the driver, a staged turning analysis is adopted, that is, the turning of the right-turning vehicle is divided into n stages. In each stage, the inner front wheels of the vehicle are regarded as performing uniform circular motion. The center angle of the circle turned by the inner front wheels of the vehicle in each stage is the same. Under this condition, a model for predicting the driving swept area of ​​right-turning vehicles is constructed;

[0013] (4) Substituting the data obtained in step (1) and the empirical radius values ​​of the front wheels of the rigid integrated vehicle and the trailer vehicle tractor at each stage obtained in step (2) into the model for predicting the travel sweep area of ​​the right-turn vehicle, and predicting the travel sweep area of ​​the right-turn vehicle that has just entered the intersection, and using the intelligent projection device to project the predicted travel sweep area of ​​the right-turn vehicle onto the ground;

[0014] (5) Establish an iterative model of the right-turn vehicle's travel swept area, iterate the right-turn vehicle's travel swept area based on the right-turn vehicle parameters captured in real time in step (1), and project the iterated right-turn vehicle's travel swept area onto the ground in real time.

[0015] The travel sweeping area of ​​the rigid one-piece vehicle is related to the travel track of the outer wheel of the front axle and the travel track of the inner wheel of the rear axle. The outer wheel and inner wheel of the front axle of the rigid one-piece vehicle are respectively recorded as the outer front wheel A' and the inner front wheel A, and the outer wheel and inner wheel of the rear axle of the rigid one-piece vehicle are respectively recorded as the outer rear wheel B' and the inner rear wheel B;

[0016] The traction head of a trailer vehicle is a rigid integrated vehicle. The outer wheel and inner wheel of the frontmost axle of the traction head of the trailer vehicle are respectively recorded as the traction head outer front wheel A' and the traction head inner front wheel A, and the outer wheel and inner wheel of the rearmost axle of the traction head of the trailer vehicle are respectively recorded as the traction head outer rear wheel B' and the traction head inner rear wheel B; the outer wheel and inner wheel of the rearmost axle of the trailer are respectively recorded as the trailer outer rear wheel C' and the trailer inner rear wheel C.

[0017] The specific steps of predicting the swept area of ​​right-turn vehicles by the model for predicting the swept area of ​​right-turn vehicles are as follows:

[0018] (4.1) Constructing the coordinate system

[0019] According to the intersection geometry parameters, the initial turning radius R1 of the front wheel point A from the center of the circle of the rigid integrated vehicle and the trailer vehicle tractor is obtained.

[0020]

[0021] h1 is the distance between the outer edge of the right-turn lane and the stop line of the intersection road exit, and h2 is the distance between the intersection road entrance and the intersection of the stop line;

[0022] Classify each vehicle entering the intersection and establish an independent coordinate system, with the stop line as the X-axis and the vehicle's forward direction perpendicular to the stop line as the Y-axis. Take a point at and take it as the origin O1(0,0);

[0023] (4.2) According to the empirical radius values ​​of the inner front wheel A of the rigid integral vehicle and the trailer vehicle tractor at each stage, the vehicle wheelbase, the vehicle track, the inner front wheel center deflection angle θ, and the movement speed of the inner front wheel of the vehicle, the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integral vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained;

[0024] (4.3) The swept area of ​​a rigid one-piece vehicle is composed of the outer front wheel track, the inner rear wheel track, the front of the vehicle, and the stop line of the right-turn vehicle exit; the swept area of ​​a trailer vehicle is composed of the outer front wheel track of the tractor, the inner rear wheel track of the trailer, the front of the trailer, and the stop line of the right-turn vehicle exit.

[0025] In step (4.2), the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained as follows:

[0026] According to the empirical radius of the inner front wheel of the rigid integrated vehicle and trailer vehicle tractor at each stage, the empirical trajectory coordinates of the inner front wheel point A of the rigid integrated vehicle and trailer vehicle tractor are obtained. When the inner front wheel point A of the rigid integrated vehicle moves to the i-th stage turning, the coordinates of point A (x A ,y A )satisfy:

[0027]

[0028] R i represents the radius of the front wheel rotating around the center of the circle in the i-th stage; θ represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage at any time and the negative X-axis in the O1 coordinate system, θ i It represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage and the negative X-axis in the O1 coordinate system at the end of the i-th stage.

[0029] The movement speed v of the front wheel at point A in the tractor of rigid integrated vehicles and trailer vehicles A The direction is along the tangent direction ε1 = (sinθ, cosθ);

[0030] The speed v of the rear wheel at point B in the tractor of a rigid integrated vehicle or trailer vehicle B Direction along direction, l is the wheelbase between the inner front wheel and the inner rear wheel of a rigid ordinary vehicle or trailer tractor, (x B ,y B ) is the trajectory coordinate of point B;

[0031] According to the geometric law of uniform circular motion, the relationship between the vehicle motion time t and θ in the i-th stage can be obtained as follows:

[0032]

[0033] According to the velocity direction of point A and the angle α between the line AB, the following is satisfied:

[0034]

[0035] The wheelbase of a rigid body remains unchanged during a turn:

[0036] (x A -x B ) 2 +(y A -y B ) 2 = l 2 (5)

[0037] v B Direction and The directions are consistent and the sizes are in multiples, including:

[0038]

[0039] Calculated

[0040] According to the velocity projection theorem, v A With v B The projections on AB are equal in size, that is, The trajectory equation of point B is obtained:

[0041]

[0042] Combining formula (3), integrating formula (7) can obtain the trajectory of point B;

[0043] According to the geometric relationship between the outer front wheel point A' and the inner front wheel point A, the coordinates (x A ',y A ') expression, A' trajectory equation:

[0044]

[0045] The center O of the uniform circular motion of the front wheel of the vehicle in the i-th stage is regarded as i The coordinates (x oi ,y oi )as follows:

[0046]

[0047] In addition, the relationship between the rear wheel in the rigid integrated vehicle and the rear wheel point B in the tractor of the trailer vehicle and the center of the turning circle O at the current stage can be obtained. i The distance R B :

[0048]

[0049] As well as the front wheel in the rigid integrated vehicle, the front wheel point A in the tractor of the trailer vehicle and the center of the turning circle O at the current stage i The distance R A :

[0050]

[0051] Take O i As the origin, the rear wheels B and O in the tractor i The connecting line is the x-axis, is the positive direction, the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established;

[0052] In the dynamic rectangular coordinate system, the coordinates of the rear wheel B in the tractor of the trailer vehicle and the rear wheel C in the trailer of the trailer vehicle are:

[0053]

[0054] Among them, l1 is the wheelbase between the rear wheels of the trailer and the rear wheels of the vehicle trailer, μ is the angle between the tractor and the centerline of the trailer, in the first stage, μ→β1, in the remaining stages, β1, β f They are the maximum turning angles of the front wheels in the tractor of rigid one-piece vehicles and trailer vehicles at the beginning of the first and last stages respectively;

[0055]

[0056] Among them, R f It is the turning radius of the vehicle in the final stage of turning.

[0057] The right-turn vehicle sweeping area is iterated based on the right-turn vehicle parameters captured in real time in step (5), mainly iterating the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, and the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer, as follows:

[0058] Real-time capture of the real trajectory coordinates of the front wheel of the right-turning rigid integrated vehicle and the front wheel of the trailer vehicle tractor at point A at the end of the jth stage in the O1 coordinate system, that is, at the beginning of the j+1th stage Calculate the inner front wheel's turning angle γ around the center O1 j ,

[0059] When the critical condition is met When γ 0 j It indicates the acute angle formed by the line connecting the inner front wheel point A and the coordinate origin O1 and the horizontal axis at the end of the jth stage in the experience trajectory, indicating that the inner front wheel of the right-turning rigid integrated vehicle enters the j+1th stage;

[0060] Grab the current front wheel deflection angle β of the rigid integrated vehicle and trailer vehicle tractor ej , vehicle speed A ;

[0061] The turning radius of the front wheel of the right-turn rigid integrated vehicle and trailer vehicle tractor at the i-th stage in the j-th iteration As shown in the following formula (17), i = 1, 2, ..., n, where the radius of the empirical trajectory of the front wheel turning right in the tractor of a rigid integrated vehicle or a trailer vehicle is R j =R 0 j ;

[0062]

[0063] The turning circle center of the front wheel of the right-turn rigid integrated vehicle and trailer vehicle tractor at the i-th stage in the j-th iteration The coordinates are as shown in formula (18), where i = j + 1, ..., n, the center of the empirical trajectory of the front wheel turning right in the tractor of the rigid integrated vehicle and the trailer vehicle is O j =O 0 j ;

[0064]

[0065] At this time, when i=j, Other θ i constant;

[0066] Iterate equations (17) and (19) into the following equation (20) to obtain the trajectory equation of the front wheel A in the tractor of the rigid integrated vehicle and trailer vehicle at the i-th stage and subsequent stages during the j-th iteration:

[0067]

[0068] Iterate equations (17) and (19) into the following equation (21) to obtain the trajectory equation of the rear wheel B of the rigid integrated vehicle and the trailer vehicle tractor at the j-th iteration in the i-th stage and subsequent stages:

[0069]

[0070] Substitute equations (3), (20) and (21) into equation (7); obtain the trajectory equation of the outer front wheel A' of the rigid integrated vehicle and the trailer vehicle tractor at the i-th stage and subsequent stages of the j-th iteration;

[0071] by point is the origin, i=j+1,…,n, The line connecting point and the rear wheel B in the tractor is the x-axis. The direction is the positive direction, and the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established;

[0072] We can get the R of stage i B and R A The values ​​are:

[0073] Substituting equations (21) and (18) into equation (22) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: B :

[0074]

[0075] Substituting equations (20) and (18) into equation (23) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: A :

[0076]

[0077] In the i-th stage and subsequent stages, the dynamic process of change over time is as follows:

[0078]

[0079] Wherein, ω1 is the angular velocity of the trailer tractor, in rad / s; ω2 is the angular velocity of the trailer, in rad / s; v B The speed of the rear wheel at point B in the trailer vehicle tractor, in m / s;

[0080] Integrate the above formula, and in the dynamic rectangular coordinate system, the included angle μ between the tractor and the center axis of the trailer in the i-th stage and subsequent stages is:

[0081]

[0082] Among them, C i The undetermined constant representing the function expression of the angle μ between the center axis of the tractor and the trailer and time t in the i-th stage is determined by the initial value of the angle μ between the center axis of the tractor and the trailer at the beginning of each stage, that is, t = 0, and the initial value is obtained by the camera; t is the movement time of the vehicle after the start of the i-th stage,

[0083] The coordinates of point C in the dynamic coordinate system are:

[0084]

[0085] The advantages of the present invention are:

[0086] (1) The present invention includes a model for predicting the travel swept area of ​​right-turn vehicles and an iterative model for the travel swept area of ​​right-turn vehicles. The model for predicting the travel swept area of ​​right-turn vehicles predicts the travel swept area of ​​vehicles that are about to turn right based on historical parameters, makes an initial reminder, and captures the actual trajectory, vehicle speed, inner front wheel deflection angle and other motion parameters of the vehicle during the right turn in real time. These parameters are input into the iterative model for the travel swept area of ​​right-turn vehicles, and the travel swept area of ​​right-turn vehicles is iteratively corrected, so that the prediction structure is more accurate and reliable.

[0087] (2) In the process of predicting the driving swept area of ​​a right-turn vehicle and iteratively correcting the driving swept area, the present invention divides the types of right-turn vehicles into integrated vehicles and trailer vehicles according to the movement characteristics of the vehicles, and uses the movement characteristics of integrated vehicles and trailer vehicles to construct a model for predicting the driving swept area of ​​a right-turn vehicle and an iterative model for the driving swept area of ​​a right-turn vehicle, so that the predicted and iteratively corrected vehicle driving swept area is more consistent with the actual swept area of ​​the vehicle.

[0088] (3) The present invention projects the predicted swept area of ​​the right-turning vehicle onto the ground in real time, which helps other traffic participants to intuitively observe the possible swept area of ​​the right-turning vehicle, avoid traffic participants from entering the swept area, and eliminate potential traffic hazards. Description of the drawings:

[0089] Figure 1 It is a schematic diagram of setting the initial radius R1 according to the intersection parameters of the present invention.

[0090] Figure 2 It is a schematic diagram of the construction of the driving sweep area model of the present invention to predict the empirical driving sweep area of ​​a rigid integrated vehicle and the O1 coordinate system.

[0091] Figure 3 The figure is a schematic diagram of the coordinate relationship between the outer front wheel A' and the inner front wheel A of the tractor of a rigid integral vehicle and a trailer vehicle predicted by the present invention.

[0092] Figure 4 Schematic diagram of the driving sweep area model predicting the empirical driving sweep area of ​​a right-turn trailer vehicle and a schematic diagram of constructing a dynamic coordinate system.

[0093] Figure 5 It is a schematic diagram of the first iterative correction of the rigid integral vehicle's running swept area according to the present invention.

[0094] Figure 6 It is a schematic diagram of the second iterative correction of the rigid integral vehicle's running swept area according to the present invention.

[0095] Figure 7 It is a schematic diagram of the first iterative correction of the swept area of ​​the trailer vehicle according to the present invention.

[0096] Figure 8 It is a schematic diagram of the second iterative correction of the swept area of ​​the trailer vehicle according to the present invention. Specific implementation method:

[0097] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0098] like Figure 1-8 As shown, a method for dynamically predicting and warning the area swept by right-turning vehicles at an intersection includes the following steps:

[0099] (1) Establishing an information acquisition system at a road intersection, wherein the intersection includes a right-turn orthogonal cross intersection, a T-intersection, and a staggered intersection, for capturing the type of vehicle about to turn right, the vehicle's own parameters, and motion parameters, wherein the type of right-turn vehicle is divided into rigid integrated vehicles and trailer vehicles;

[0100] The information acquisition system includes cameras installed above and on the side of the right-turn lane. The video captured by the camera above the right-turn lane can be used to analyze the wheelbase, inner front wheel angle, vehicle length, and vehicle length of the vehicle entering the right-turn area; the video captured by the camera on the side of the right-turn lane can be used to determine the type of vehicle entering the right-turn area and analyze the vehicle's wheelbase and vehicle compartment height.

[0101] (2) Collect historical videos of right-turning vehicles at the intersection, process the video information, obtain empirical radius values ​​of the front wheels at each stage of the rigid integrated vehicle and the trailer vehicle tractor, and obtain the geometric parameters of the road at the intersection;

[0102] (3) It is stipulated that when the inner rear wheels of the rigid integrated vehicle and the inner rear wheels of the truck trailer reach the stop line, the driver starts to turn right. In order to be close to the actual driving situation of the driver, a staged turning analysis is adopted, that is, the turning of the right-turning vehicle is divided into n stages. In each stage, the inner front wheels of the vehicle are regarded as performing uniform circular motion. The center angle of the circle turned by the inner front wheels of the vehicle in each stage is the same. Under this condition, a model for predicting the driving swept area of ​​right-turning vehicles is constructed;

[0103] (4) Substituting the data obtained in step (1) and the empirical radius values ​​of the front wheels of the rigid integrated vehicle and the trailer vehicle tractor at each stage obtained in step (2) into the model for predicting the travel sweep area of ​​the right-turn vehicle, and predicting the travel sweep area of ​​the right-turn vehicle that has just entered the intersection, and using the intelligent projection device to project the predicted travel sweep area of ​​the right-turn vehicle onto the ground;

[0104] (5) Establish an iterative model of the right-turn vehicle's travel swept area, iterate the right-turn vehicle's travel swept area based on the right-turn vehicle parameters captured in real time in step (1), and project the iterated right-turn vehicle's travel swept area onto the ground in real time.

[0105] In the present invention, the travel sweeping area of ​​the rigid one-piece vehicle is related to the travel track of the outer wheel of the frontmost axle and the travel track of the inner wheel of the rearmost axle. The outer wheel and inner wheel of the frontmost axle of the rigid one-piece vehicle are respectively recorded as the outer front wheel A' and the inner front wheel A, and the outer wheel and inner wheel of the rearmost axle of the rigid one-piece vehicle are respectively recorded as the outer rear wheel B' and the inner rear wheel B;

[0106] The traction head of a trailer vehicle is a rigid integrated vehicle. The outer wheel and inner wheel of the frontmost axle of the traction head of the trailer vehicle are respectively recorded as the traction head outer front wheel A' and the traction head inner front wheel A, and the outer wheel and inner wheel of the rearmost axle of the traction head of the trailer vehicle are respectively recorded as the traction head outer rear wheel B' and the traction head inner rear wheel B; the outer wheel and inner wheel of the rearmost axle of the trailer are respectively recorded as the trailer outer rear wheel C' and the trailer inner rear wheel C.

[0107] Among them, the specific steps of the model for predicting the swept area of ​​right-turn vehicles are as follows:

[0108] (4.1) Constructing the coordinate system

[0109] According to the intersection geometry parameters, the initial turning radius R1 of the front wheel point A from the center of the circle of the rigid integrated vehicle and the trailer vehicle tractor is obtained.

[0110]

[0111] h1 is the distance between the outer edge of the right-turn lane and the stop line of the intersection road exit, and h2 is the distance between the intersection road entrance and the intersection of the stop line;

[0112] Classify each vehicle entering the intersection and establish an independent coordinate system, with the stop line as the X-axis and the vehicle's forward direction perpendicular to the stop line as the Y-axis. Take a point at and take it as the origin O1(0,0);

[0113] (4.2) According to the empirical radius values ​​of the inner front wheel A of the rigid integral vehicle and the trailer vehicle tractor at each stage, the vehicle wheelbase, the vehicle track, the inner front wheel center deflection angle θ, and the movement speed of the inner front wheel of the vehicle, the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integral vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained;

[0114] (4.3) The swept area of ​​a rigid one-piece vehicle is composed of the outer front wheel track, the inner rear wheel track, the front of the vehicle, and the stop line of the right-turn vehicle exit; the swept area of ​​a trailer vehicle is composed of the outer front wheel track of the tractor, the inner rear wheel track of the trailer, the front of the trailer, and the stop line of the right-turn vehicle exit.

[0115] In step (4.2), the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained as follows:

[0116] According to the empirical radius of the inner front wheel of the rigid integrated vehicle and trailer vehicle tractor at each stage, the empirical trajectory coordinates of the inner front wheel point A of the rigid integrated vehicle and trailer vehicle tractor are obtained. When the inner front wheel point A of the rigid integrated vehicle moves to the i-th stage turning, the coordinates of point A (x A ,y A )satisfy:

[0117]

[0118] R i represents the radius of the front wheel rotating around the center of the circle in the i-th stage; θ represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage at any time and the negative X-axis in the O1 coordinate system, θ i It represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage and the negative X-axis in the O1 coordinate system at the end of the i-th stage.

[0119] The movement speed v of the front wheel at point A in the tractor of rigid integrated vehicles and trailer vehicles A The direction is along the tangent direction ε1 = (sinθ, cosθ);

[0120] The speed v of the rear wheel at point B in the tractor of a rigid integrated vehicle or trailer vehicle B Direction along direction, l is the wheelbase between the inner front wheel and the inner rear wheel of a rigid ordinary vehicle or trailer tractor, (x B ,y B ) is the trajectory coordinate of point B;

[0121] According to the geometric law of uniform circular motion, the relationship between the vehicle motion time t and θ in the i-th stage can be obtained as follows:

[0122]

[0123] According to the velocity direction of point A and the angle α between the line AB, the following is satisfied:

[0124]

[0125] The wheelbase of a rigid body remains unchanged during a turn:

[0126] (x A -x B ) 2 +(y A -y B ) 2 = l 2 (5)

[0127] v B Direction and The directions are consistent and the sizes are in multiples, including:

[0128]

[0129] Calculated

[0130] According to the velocity projection theorem, v A With v B The projections on AB are equal in size, that is, The trajectory equation of point B is obtained:

[0131]

[0132] Combining formula (3), integrating formula (7) can obtain the trajectory of point B;

[0133] According to the geometric relationship between the outer front wheel point A' and the inner front wheel point A, the coordinates (x A ',y A ') expression, A' trajectory equation:

[0134]

[0135] The center O of the uniform circular motion of the front wheel of the vehicle in the i-th stage is regarded as i The coordinates (x oi ,y oi )as follows:

[0136]

[0137] In addition, the relationship between the rear wheel in the rigid integrated vehicle and the rear wheel point B in the tractor of the trailer vehicle and the center of the turning circle O at the current stage can be obtained. i The distance R B :

[0138]

[0139] As well as the front wheel in the rigid integrated vehicle, the front wheel point A in the tractor of the trailer vehicle and the center of the turning circle O at the current stage i The distance R A :

[0140]

[0141] Take O i As the origin, the rear wheels B and O in the tractor i The connecting line is the x-axis, is the positive direction, the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established;

[0142] In the dynamic rectangular coordinate system, the coordinates of the rear wheel B in the tractor of the trailer vehicle and the rear wheel C in the trailer of the trailer vehicle are:

[0143]

[0144] Among them, l1 is the wheelbase between the rear wheels of the trailer and the rear wheels of the vehicle trailer, μ is the angle between the tractor and the centerline of the trailer, in the first stage, μ→β1, in the remaining stages, β1, β f They are the maximum turning angles of the front wheels in the tractor of rigid one-piece vehicles and trailer vehicles at the beginning of the first and last stages respectively;

[0145]

[0146] Among them, R f is the turning radius of the vehicle in the final stage of turning, is the maximum turning angle of the vehicle. It is related to the actual size and height of the vehicle. We conducted a survey on the vehicles on the market to obtain the maximum turning angles of different types of vehicles. Value, vehicle large turning angle The value can be the mean of the survey results.

[0147] The right-turn vehicle sweeping area is iterated based on the right-turn vehicle parameters captured in real time in step (5), mainly iterating the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, and the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer, as follows:

[0148] Real-time capture of the real trajectory coordinates of the front wheel of the right-turning rigid integrated vehicle and the front wheel of the trailer vehicle tractor at point A at the end of the jth stage in the O1 coordinate system, that is, at the beginning of the j+1th stage Calculate the inner front wheel's turning angle γ around the center O1 j ,

[0149] When the critical condition is met When γ 0 j It indicates the acute angle formed by the line connecting the inner front wheel point A and the coordinate origin O1 and the horizontal axis at the end of the jth stage in the experience trajectory, indicating that the inner front wheel of the right-turning rigid integrated vehicle enters the j+1th stage;

[0150] Grab the current front wheel deflection angle β of the rigid integrated vehicle and trailer vehicle tractor ej , vehicle speed A ;

[0151] The turning radius of the front wheel of the right-turn rigid integrated vehicle and trailer vehicle tractor at the i-th stage in the j-th iteration As shown in the following formula (17), i = 1, 2, ..., n, where the radius of the empirical trajectory of the front wheel turning right in the tractor of a rigid integrated vehicle or a trailer vehicle is R j =R 0 j ;

[0152]

[0153] The turning circle center of the front wheel of the right-turn rigid integrated vehicle and trailer vehicle tractor at the i-th stage in the j-th iteration The coordinates are as shown in formula (18), where i = j + 1, ..., n, the center of the empirical trajectory of the front wheel turning right in the tractor of the rigid integrated vehicle and the trailer vehicle is O j =O 0 j ;

[0154]

[0155] At this time, when i=j, Other θ i constant;

[0156] Iterate equations (17) and (19) into the following equation (20) to obtain the trajectory equation of the front wheel A in the tractor of the rigid integrated vehicle and trailer vehicle at the i-th stage and subsequent stages during the j-th iteration:

[0157]

[0158] Iterate equations (17) and (19) into the following equation (21) to obtain the trajectory equation of the rear wheel B of the rigid integrated vehicle and the trailer vehicle tractor at the j-th iteration in the i-th stage and subsequent stages:

[0159]

[0160] Substitute equations (3), (20) and (21) into equation (7); obtain the trajectory equation of the outer front wheel A' of the rigid integrated vehicle and the trailer vehicle tractor at the i-th stage and subsequent stages of the j-th iteration;

[0161] by point is the origin, i=j+1,…,n, The line connecting point and the rear wheel B in the tractor is the x-axis. The direction is the positive direction, and the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established;

[0162] We can get the R of stage i B and R A The values ​​are:

[0163] Substituting equations (21) and (18) into equation (22) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: B :

[0164]

[0165] Substituting equations (20) and (18) into equation (23) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: A :

[0166]

[0167] In the i-th stage and subsequent stages, the dynamic process of change over time is as follows:

[0168]

[0169] Wherein, ω1 is the angular velocity of the trailer tractor, in rad / s; ω2 is the angular velocity of the trailer, in rad / s; v B The speed of the rear wheel at point B in the trailer vehicle tractor, in m / s;

[0170] Integrate the above formula, and in the dynamic rectangular coordinate system, the included angle μ between the tractor and the center axis of the trailer in the i-th stage and subsequent stages is:

[0171]

[0172] Among them, C iThe undetermined constant representing the function expression of the angle μ between the center axis of the tractor and the trailer and time t in the i-th stage is determined by the initial value of the angle μ between the center axis of the tractor and the trailer at the beginning of each stage, that is, t = 0, and the initial value is obtained by the camera; t is the movement time of the vehicle after the start of the i-th stage,

[0173] The coordinates of point C in the dynamic coordinate system are:

[0174]

[0175] The above is a method for dynamically predicting and reminding the driving swept area of ​​a right-turning vehicle. When multiple vehicles turn right, the driving swept area is dynamically predicted for each vehicle separately, and the predicted driving swept areas of all vehicles are combined and displayed through projection.

[0176] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for dynamically predicting and warning the area swept by right-turning vehicles at an intersection, characterized in that: The following steps are involved: (1) Establishing an information acquisition system at a road intersection, wherein the intersection includes a right-turn orthogonal cross intersection, a T-intersection, and a staggered intersection, for capturing the type of vehicle about to turn right, the vehicle's own parameters, and motion parameters, wherein the type of right-turn vehicle is divided into a rigid integral vehicle and a trailer vehicle; (2) Collect historical videos of right-turning vehicles at the intersection, process the video information, obtain empirical radius values ​​of the front wheels of rigid integrated vehicles and trailer vehicles at each stage, and obtain geometric parameters of the road at the intersection; (3) It is stipulated that when the inner rear wheels of the rigid integrated vehicle and the inner rear wheels of the truck trailer reach the stop line, the driver starts to turn right. In order to be close to the actual driving situation of the driver, a staged turning analysis is adopted, that is, the turning of the right-turning vehicle is divided into n stages. In each stage, the inner front wheels of the vehicle are regarded as performing uniform circular motion. The center angle of the circle turned by the inner front wheels of the vehicle in each stage is the same. Under this condition, a model for predicting the driving swept area of ​​right-turning vehicles is constructed; (4) Substituting the data obtained in step (1) and the empirical radius values ​​of the front wheels of the rigid integrated vehicle and the trailer vehicle tractor at each stage obtained in step (2) into the model for predicting the travel sweep area of ​​the right-turn vehicle, and predicting the travel sweep area of ​​the right-turn vehicle that has just entered the intersection, and projecting the predicted travel sweep area of ​​the right-turn vehicle onto the ground using an intelligent projection device; (5) establishing an iterative model of the right-turn vehicle travel sweep area, iterating the right-turn vehicle travel sweep area based on the right-turn vehicle parameters captured in real time in step (1), and projecting the iterated right-turn vehicle travel sweep area onto the ground in real time; The specific steps of predicting the swept area of ​​right-turn vehicles by the model for predicting the swept area of ​​right-turn vehicles are as follows: (4.1) Constructing the coordinate system According to the intersection geometry parameters, the initial turning radius R1 of the front wheel point A from the center of the circle of the rigid integrated vehicle and the trailer vehicle tractor is obtained. h1 is the distance between the outer edge of the right-turn lane and the stop line of the intersection road exit, and h2 is the distance between the intersection road entrance and the intersection of the stop line; Classify each vehicle entering the intersection and establish an independent coordinate system, with the stop line as the X-axis and the vehicle's forward direction perpendicular to the stop line as the Y-axis. Take a point at and take it as the origin O1(0,0); (4.2) According to the empirical radius values ​​of the inner front wheel A of the rigid integral vehicle and the trailer vehicle tractor at each stage, the vehicle wheelbase, the vehicle track, the inner front wheel center deflection angle θ, and the movement speed of the inner front wheel of the vehicle, the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integral vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained; (4.3) The swept area of ​​a rigid integrated vehicle is composed of the outer front wheel track, the inner rear wheel track, the front of the vehicle, and the stop line of the right-turn vehicle exit; the swept area of ​​a trailer vehicle is composed of the outer front wheel track of the tractor, the inner rear wheel track of the trailer, the front of the trailer, and the stop line of the right-turn vehicle exit; In step (4.2), the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, as well as the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer are obtained as follows: According to the empirical radius of the inner front wheel of the rigid integrated vehicle and trailer vehicle tractor at each stage, the empirical trajectory coordinates of the inner front wheel point A of the rigid integrated vehicle and trailer vehicle tractor are obtained. When the inner front wheel point A of the rigid integrated vehicle moves to the i-th stage turning, the coordinates of point A (x A ,y A )satisfy: R i represents the radius of the front wheel rotating around the center of the circle in the i-th stage; θ represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage at any time and the negative X-axis in the O1 coordinate system, θ i It represents the angle between the line connecting the front wheel of the vehicle and the center of the circle in the current stage and the negative X-axis in the O1 coordinate system at the end of the i-th stage. The movement speed v of the front wheel at point A in the tractor of a rigid integrated vehicle or trailer vehicle A The direction is along the tangent direction ε1 = (sinθ, cosθ); The speed v of the rear wheel at point B in the tractor of a rigid integrated vehicle or trailer vehicle B Direction along direction, l is the wheelbase between the inner front wheel and the inner rear wheel of a rigid ordinary vehicle or trailer vehicle tractor, (x B ,y B ) is the trajectory coordinate of point B; According to the geometric law of uniform circular motion, the relationship between the vehicle motion time t and θ in the i-th stage is: According to the velocity direction of point A and the angle α between the line AB, the following is satisfied: The wheelbase of a rigid body remains unchanged during a turn: (x A -x B ) 2 +(and A -and B ) 2 =l 2 (5) v B Direction and The directions are consistent and the sizes are in multiples, including: Right now Calculated According to the velocity projection theorem, v A With v B The projections on AB are equal in size, that is, The trajectory equation of point B is obtained: Combining formula (3), integrating formula (7) can obtain the trajectory of point B; According to the geometric relationship between the outer front wheel point A' and the inner front wheel point A, the coordinates (x A ',y A ') expression, A' trajectory equation: The center O of the circle where the front wheel of the vehicle moves in uniform circular motion in the i-th stage is regarded as i The coordinates (x oi ,y oi )as follows: In addition, the inner rear wheel of the rigid integrated vehicle, the inner rear wheel point B of the trailer vehicle tractor and the turning circle center O at the current stage are obtained. i The distance R B : As well as the front wheel in the rigid integrated vehicle, the front wheel point A in the tractor of the trailer vehicle and the center of the turning circle O at the current stage i The distance R A : Take O i As the origin, the rear wheels B and O in the tractor i The connecting line is the x-axis, is the positive direction, the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established; In the dynamic rectangular coordinate system, the coordinates of the rear wheel B in the tractor of the trailer vehicle and the rear wheel C in the trailer of the trailer vehicle are: Among them, l1 is the wheelbase between the rear wheels of the trailer and the rear wheels of the vehicle trailer, μ is the angle between the tractor and the centerline of the trailer, in the first stage, μ→β1, in the remaining stages, β1, β f They are the maximum turning angles of the front wheels in the tractor of rigid integral vehicles and trailer vehicles at the beginning of the first and last stages respectively; Among them, R f is the turning radius of the vehicle in the final stage of turning, is the maximum turning angle of the vehicle; The right-turn vehicle sweeping area is iterated based on the right-turn vehicle parameters captured in real time in step (5), mainly iterating the outer front wheel driving trajectory and the inner rear wheel driving trajectory of the rigid integrated vehicle, and the outer front wheel driving trajectory of the truck trailer tractor and the inner rear wheel driving trajectory of the trailer, as follows: Real-time capture of the real trajectory coordinates A of the front wheel inside the right-turning rigid integrated vehicle and the front wheel inside the tractor of the trailer vehicle at the end of the jth stage in the O1 coordinate system, that is, the beginning of the j+1th stage ej Calculate the inner front wheel's turning angle γ around the center O1 j , When the critical condition is met When γ 0 j It indicates the acute angle formed by the line connecting the inner front wheel point A and the coordinate origin O1 and the horizontal axis at the end of the jth stage in the empirical trajectory, indicating that the inner front wheel of the right-turning rigid integrated vehicle enters the j+1th stage; Capture the current front wheel deflection angle β of the rigid integrated vehicle and trailer vehicle tractor ej , vehicle speed A ; The turning radius of the front wheel of the tractor of a right-turning rigid-unit vehicle or trailer vehicle at the i-th stage in the j-th iteration As shown in the following formula (17), i = 1, 2, ..., n, where the empirical trajectory radius R of the front wheel turning right in the tractor of a rigid integrated vehicle or a trailer vehicle is j =R 0 j ; The turning circle center of the front wheel of the tractor of a right-turning rigid integrated vehicle or trailer vehicle at the i-th stage in the j-th iteration The coordinates are as shown in formula (18), where i = j + 1, ..., n, the center of the empirical trajectory of the front wheel turning right in the tractor of the rigid integrated vehicle and the trailer vehicle is O j =O 0 j ; At this time, when i=j, Other θ i constant; Iterate equations (17) and (19) into the following equation (20) to obtain the trajectory equation of the front wheel A in the tractor of the rigid integrated vehicle and trailer vehicle at the i-th stage and subsequent stages during the j-th iteration: Iterate equations (17) and (19) into the following equation (21) to obtain the trajectory equation of the rear wheel B of the rigid integrated vehicle and the trailer vehicle tractor at the j-th iteration in the i-th stage and subsequent stages: Substitute equations (3), (20) and (21) into equation (7); obtain the trajectory equation of the outer front wheel A' of the rigid integrated vehicle and the trailer vehicle tractor at the i-th stage and subsequent stages of the j-th iteration; by point is the origin, i=j+1,…,n, The line connecting point and the rear wheel B in the tractor is the x-axis. The direction is the positive direction, and the vehicle moving direction perpendicular to the x-axis is the positive direction of the y-axis, and a new dynamic rectangular coordinate system is established; Get the R of stage i B and R A The values ​​are: Substituting equations (21) and (18) into equation (22) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: B : Substituting equations (20) and (18) into equation (23) below, we can obtain the R of the tractor in the i-th stage and subsequent stages: A : In the i-th stage and subsequent stages, the dynamic process of change over time is as follows: Wherein, ω1 is the angular velocity of the trailer tractor, in rad / s; ω2 is the angular velocity of the trailer, in rad / s; v B The speed of the rear wheel at point B in the trailer vehicle tractor, in m / s; Integrate the above formula, and in the dynamic rectangular coordinate system, the included angle μ between the tractor and the center axis of the trailer in the i-th stage and subsequent stages is: Among them, C i The undetermined constant representing the function expression of the angle μ between the center axis of the tractor and the trailer and time t in the i-th stage is determined by the initial value of the angle μ between the center axis of the tractor and the trailer at the beginning of each stage, that is, t = 0, and the initial value is obtained by the camera; t is the movement time of the vehicle after the start of the i-th stage, The coordinates of point C in the dynamic coordinate system are:

2. The method for dynamic prediction and warning of the right-turn vehicle sweeping area at an intersection according to claim 1 is characterized in that: The sweeping area of ​​the rigid one-piece vehicle is related to the outer wheel driving track of its frontmost axle and the inner wheel driving track of the rearmost axle. The outer wheel and inner wheel of the frontmost axle of the rigid one-piece vehicle are respectively recorded as the outer front wheel A' and the inner front wheel A, and the outer wheel and inner wheel of the rearmost axle of the rigid one-piece vehicle are respectively recorded as the outer rear wheel B' and the inner rear wheel B; The tractor of a trailer vehicle is a rigid integrated vehicle. The outer wheel and inner wheel of the frontmost axle of the tractor of the trailer vehicle are respectively recorded as the tractor outer front wheel A' and the tractor inner front wheel A, and the outer wheel and inner wheel of the rearmost axle of the tractor of the trailer vehicle are respectively recorded as the tractor outer rear wheel B' and the tractor inner rear wheel B; the outer wheel and inner wheel of the rearmost axle of the trailer are respectively recorded as the trailer outer rear wheel C' and the trailer inner rear wheel C.

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