A method for traffic safety judgment and regulation in a curved road in a connected environment

Abstract

The application discloses a kind of net link environment under the bend traffic safety discrimination and regulation method, comprising:1, calculate the following car follow path;2, calculate the collision time of two cars;3, calculate the collision time change rate;4, traffic safety discrimination is carried out in combination with collision time and collision time change rate;5, consider front and rear car safety risk and regulate;6, the above steps are recycled until the control duration ends.The application can accurately carry out traffic safety discrimination when vehicle runs on curved road section, real-time explore potential traffic accident, so as to reduce the driving risk of vehicle when driving on curve, and can improve the operation efficiency and safety of vehicle on curve.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of networked vehicle traffic control, and particularly relates to a method for judging and regulating traffic safety of a curved road in a networked environment. BACKGROUND

[0002] A curved road section is an important part of road traffic. Due to the particularity of the linear design of the curved road section, the driving stability of the vehicle is lower than that of straight-line driving, and it is an easy-to-occur section of traffic accidents and traffic congestion.

[0003] With the development of networked automatic driving technology and vehicle-road cooperation technology, we have a new way to solve traffic problems. Compared with manually driven vehicles, networked automatic driving vehicles can drive with shorter headway, faster reaction speed and more intelligent driving behavior. In the past, the safety of vehicle following was mainly focused on straight-line driving, but in real driving behavior, there are a large number of curved following behaviors. Compared with straight-line driving scenarios, curved scenarios have a higher accident rate due to the limitations of visibility and geometric linearity. Curved following must break through the linear limitations of straight-line driving to plan a planar motion containing steering, which also brings difficulties to calculating the actual following distance between the two vehicles before and after the curve. SUMMARY

[0004] The present application overcomes the deficiencies of the prior art and provides a method for judging and regulating traffic safety of a curved road in a networked environment, so as to accurately judge traffic safety when vehicles are running on a curved road section, discover potential traffic accidents in real time, thereby reducing the driving risk of vehicles on a curved road and improving the running efficiency and safety of vehicles on a curved road.

[0005] To achieve the above-mentioned purposes, the present application adopts the following technical solutions:

[0006] The present application is characterized in that the motor vehicles in the networked environment are all networked automatic driving vehicles, the road on which the networked automatic driving vehicles in the networked environment drive is a one-way curved road section, and the method for judging and regulating traffic safety of a curved road in a networked environment comprises the following steps:

[0007] Step 1, defining a target vehicle driving on the curved road section as vehicle 2, the first vehicle behind vehicle 2 as vehicle 1, and the first two vehicles in front of vehicle 2 as vehicle 3 and vehicle 4 according to the distance from vehicle 2;

[0008] Taking the intersection of the starting line of the curved road section and the road center line as the origin, taking the driving direction of the vehicle on the upstream straight road section of the curved road section as the positive direction of the x-axis, and taking the direction perpendicular to the x-axis and pointing to the inside of the curved road as the positive direction of the y-axis, a plane rectangular coordinate system is established;

[0009] Collecting the speed of vehicle m at time t by using roadside intelligent traffic equipment acceleration heading angle position horizontal coordinate and position vertical coordinate wherein m = 1, 2, 3, 4;

[0010] Let Δt be the update time interval;

[0011] Step 2, planning the car-following path of vehicle j, wherein j = 1, 2, 3;

[0012] Step 2.1, constructing the car-following path function of vehicle j by using formula (1);

[0013]

[0014] In formula (1), x j and y j represent the position horizontal coordinate and the position vertical coordinate of vehicle j respectively, a j , b j , c j , d j represent four parameters in the car-following path function of the jth vehicle respectively;

[0015] Step 2.2, solving the four parameters in formula (1) by using formula (2);

[0016]

[0017] In formula (2), x and y represent the position horizontal coordinate and the position vertical coordinate of vehicle j at time t respectively, x and y represent the position horizontal coordinate and the position vertical coordinate of vehicle j+1 at time t respectively, and and represent the heading angle of vehicle j and vehicle j+1 at time t respectively;

[0018] Step 3, calculating the collision time of vehicle j and vehicle j+1 at time t

[0019] Step 4, calculating the collision time variation rate between vehicle 2 and vehicle 3 at time t

[0020] Step 5, if formula (9) is satisfied, it means that vehicle 2 and vehicle 3 are in a safe driving state at time t, and entering step 10; otherwise, entering step 6;

[0021]

[0022] Step 6, if and , it indicates that the vehicle 2 and the vehicle 3 are in a low-risk driving state at the time t, and after sending a driving safety reminder to the vehicle 2 and the vehicle 3, step 10 is entered;

[0023] if and , it indicates that the vehicle 2 and the vehicle 3 are in a medium-risk driving state at the time t, and after sending a driving safety warning to the vehicle 2 and the vehicle 3, step 10 is entered;

[0024] if and , it indicates that the vehicle 2 and the vehicle 3 are in a high-risk driving state at the time t, and after sending a driving safety warning to the vehicle 2 and the vehicle 3, step 7 is entered;

[0025] Step 7, it is judged whether is established, if yes, step 8 is entered; otherwise, step 9 is entered;

[0026] Step 8, after speed regulation is performed on the vehicle behind the vehicle 3, step 10 is entered;

[0027] Step 9, after speed regulation is performed on the vehicle in front of the vehicle 2, step 10 is entered;

[0028] Step 10, t+Δt is assigned to t, and it is judged whether t≥T is established, if yes, the regulation process is ended; otherwise, step 2 is returned to be sequentially executed, and T represents the total regulation time length.

[0029] The traffic safety judgment and regulation method in the network environment has the characteristics that the step 3 comprises:

[0030] Step 3.1, the arc distance between the vehicle j and the vehicle j+1 at the time t is calculated by using formula (3)

[0031]

[0032] In formula (3), l j represents the vehicle length of the vehicle j, l j+1 represents the vehicle length of the vehicle j+1, y′ j represents the first derivative of y j ;

[0033] Step 3.2, the collision time between the vehicle j and the vehicle j+1 at the time t is calculated by using formula (4)

[0034]

[0035] In formula (4), TTC safedenotes a safe time-to-collision threshold.

[0036] The step 4 comprises:

[0037] Step 4.1, calculating the speed of the vehicle 2 and the vehicle 3 at the time t+Δt by using the formula (5) and

[0038]

[0039] Step 4.2, calculating the displacement of the vehicle 2 and the vehicle 3 within the time t to t+Δt by using the formula (6) and

[0040]

[0041] Step 4.3, calculating the time-to-collision of the vehicle 2 and the vehicle 3 at the time t+Δt by using the formula (7)

[0042]

[0043] Step 4.4, calculating the rate of change of the time-to-collision between the vehicle 2 and the vehicle 3 at the time t by using the formula (8)

[0044]

[0045] The step 8 comprises:

[0046] Step 8.1, calculating the critical value of the acceleration of the vehicle 2 at the time t+Δt when the vehicle 2 and the vehicle 3 are at the safe time-to-collision threshold by using the formula (10)

[0047]

[0048] Step 8.2, calculating the critical value of the acceleration of the vehicle 2 at the time t+Δt when the vehicle 1 and the vehicle 2 are at the safe time-to-collision threshold by using the formula (11)

[0049]

[0050] Step 8.3, judging whether the following formula is true or not, if true, then after regulating the acceleration of the vehicle 2 within the range of at the time t, entering the step 10; otherwise, after regulating the acceleration of the vehicle 2 to be at the time t and the vehicle behind the vehicle 2 to be coordinated to decelerate, entering the step 10.

[0051] The step 9 comprises:

[0052] Step 9.1, calculating the critical value of the acceleration of vehicle 3 at t+Δt when vehicle 2 and vehicle 3 are at the safe collision time threshold by using formula (12)

[0053]

[0054] Step 9.2, calculating the critical value of the acceleration of vehicle 3 at t+Δt when vehicle 3 and vehicle 4 are at the safe collision time threshold by using formula (13)

[0055]

[0056] Step 9.3, judging whether or not is true, if true, after regulating the acceleration of vehicle 3 in the range of at t, entering step 10; otherwise, after vehicle 3 and the vehicle in front of vehicle 3 perform cooperative acceleration, regulating the acceleration of vehicle 3 as at t, entering step 10.

[0057] The electronic device of the present application comprises a memory and a processor, characterized in that the memory is used to store a program supporting the processor to execute the curve traffic safety discrimination and regulation method, and the processor is configured to execute the program stored in the memory.

[0058] The computer readable storage medium of the present application, characterized in that the computer readable storage medium stores a computer program, and the computer program is executed by the processor to perform the steps of the curve traffic safety discrimination and regulation method.

[0059] Compared with the prior art, the beneficial technical effects of the present application are embodied in:

[0060] 1. The present application establishes a cubic polynomial dynamic simulation vehicle curve following path, which can accurately simulate the real vehicle following path, so as to better calculate the arc distance between the front and rear vehicles.

[0061] 2. Compared with the prior art, the present application proposes a collision time variation rate DTTC based on the collision time TTC, fully considers the variation trend of the collision time, and thus more accurately judges the vehicle following safety state.

[0062] 3. Compared with the prior art, the present application fully considers the influence on other vehicles when regulating the target vehicle, thereby being beneficial to improving the road traffic efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0063] Figure 1 is the overall flowchart of the present application;

[0064] Figure 2 This is a flowchart of the decision-making method of the present invention;

[0065] Figure 3 This is a schematic diagram of a scenario according to the present invention. Detailed Implementation

[0066] In this embodiment, a method for determining and controlling traffic safety on curves in a connected environment is described, wherein the motor vehicles in the connected environment are all connected autonomous vehicles; the roads in which the connected autonomous vehicles travel are one-way curved road sections; such as Figure 1 As shown, the method for judging and controlling traffic safety on curves includes the following steps:

[0067] Step 1, as follows Figure 3 As shown, the target vehicle traveling on the curved road section is defined as vehicle 2, the first vehicle behind vehicle 2 is defined as vehicle 1, and the two vehicles in front of vehicle 2 are defined as vehicle 3 and vehicle 4 respectively according to their distance from vehicle 2 from closest to farthest.

[0068] A Cartesian coordinate system is established with the intersection of the starting line of the curved road segment and the center line of the road as the origin, the direction of travel of vehicles on the straight section upstream of the curved road segment as the positive x-axis, and the direction perpendicular to the x-axis and pointing to the inside of the curve as the positive y-axis.

[0069] Using roadside intelligent transportation equipment to collect the speed (m) of a vehicle at time t. acceleration Heading angle x-coordinate of position and position ordinate Where m = 1, 2, 3, 4;

[0070] Let Δt be the update time interval.

[0071] Step 2, as follows Figure 2 As shown, plan the following path for vehicle j, where j = 1, 2, 3;

[0072] Step 2.1: Construct the car-following path function for vehicle j using equation (1);

[0073]

[0074] In equation (1), x j and y j Let a represent the x-coordinate and y-coordinate of vehicle j, respectively. j b j c j d j These represent the four parameters in the car-following path function for the j-th vehicle;

[0075] The cubic polynomial has higher linearity fitting degree, simple calculation and real-time adaptability, so the cubic polynomial is selected as the following path curve.

[0076] Step 2.2, solving the four parameters in formula (1) by using formula (2);

[0077]

[0078] In formula (2), and respectively represent the position horizontal coordinate and the position vertical coordinate of vehicle j at time t, and respectively represent the position horizontal coordinate and the position vertical coordinate of vehicle j+1 at time t, and respectively represent the heading angle of vehicle j and vehicle j+1 at time t;

[0079] The four parameters in the cubic polynomial are solved by using the four information of the rear vehicle position, the rear vehicle heading angle, the front vehicle position and the front vehicle heading angle.

[0080] Step 3, calculating the collision time of vehicle j and vehicle j+1;

[0081] Step 3.1, solving the arc distance between vehicles by using the planned path function to replace the straight line distance, and calculating the arc distance between vehicle j and vehicle j+1 at time t by using formula (3)

[0082]

[0083] In formula (3), l j represents the vehicle length of vehicle j, l j+1 represents the vehicle length of vehicle j+1, and y′ j represents the first derivative of y j .

[0084] Step 3.2, calculating the collision time between vehicle j and vehicle j+1 at time t by using formula (4)

[0085]

[0086] In formula (4), TTC safe represents the safety collision time threshold;

[0087] Using the arc distance to replace the straight line distance on the curve makes the calculation more accurate, and when the rear vehicle speed is less than the front vehicle speed, the safety collision time threshold is used to represent their TTC to avoid the TTC becoming negative.

[0088] Step 4, calculate the collision time rate of change between vehicle 2 and vehicle 3;

[0089] Step 4.1, calculate the speed of vehicle 2 and vehicle 3 at t+Δt time by formula (5) and

[0090]

[0091] Step 4.2, calculate the displacement of vehicle 2 and vehicle 3 from t to t+Δt time by formula (6) and

[0092]

[0093] Step 4.3, calculate the collision time of vehicle 2 and vehicle 3 at t+Δt time by formula (7)

[0094]

[0095] Step 4.4, calculate the collision time rate of change between vehicle 2 and vehicle 3 at t time by formula (8)

[0096]

[0097] Introducing the collision time rate of change, more accurately judge the driving safety state of two vehicles.

[0098] Step 5, if formula (9) is satisfied, it means that vehicle 2 and vehicle 3 are in a safe driving state at t time, and enter step 10; otherwise, enter step 6;

[0099]

[0100] Step 6, if and it means that vehicle 2 and vehicle 3 are in a low-risk driving state at t time, and after sending a driving safety reminder to vehicle 2 and vehicle 3, enter step 10;

[0101] if and it means that vehicle 2 and vehicle 3 are in a medium-risk driving state at t time, and after sending a driving safety warning to vehicle 2 and vehicle 3, enter step 10;

[0102] if and it means that vehicle 2 and vehicle 3 are in a high-risk driving state at t time, and after sending a driving safety warning to vehicle 2 and vehicle 3, enter step 7;

[0103] The TTC and the DTTC are combined to determine the driving safety risk, and the risk is divided into four levels according to the risk severity, and the front or rear vehicle is regulated when the risk is high.

[0104] Step 7, determining whether the condition is met, if yes, go to step 8; otherwise, go to step 9;

[0105] The TTC between the vehicle 1 and the vehicle 2 and the TTC between the vehicle 3 and the vehicle 4 are compared to determine whether the front or rear vehicle is regulated.

[0106] Step 8, regulating the speed of the vehicle 3 behind the vehicle 2;

[0107] Step 8.1, calculating the critical value of the acceleration of the vehicle 2 at t+Δt using formula (10) to make the vehicle 2 and the vehicle 3 have the safe TTC at t+Δt

[0108]

[0109] Calculating the acceleration range of the vehicle 2 to make the vehicle 2 and the vehicle 3 safe

[0110] Step 8.2, calculating the critical value of the acceleration of the vehicle 2 at t+Δt using formula (11) to make the vehicle 1 and the vehicle 2 have the safe TTC at t+Δt

[0111]

[0112] Calculating the acceleration range of the vehicle 2 to make the vehicle 1 and the vehicle 2 safe

[0113] Step 8.3, determining whether the condition is met, if yes, go to step 10 after regulating the acceleration of the vehicle 2 at t to be in the range of , otherwise, go to step 10 after regulating the acceleration of the vehicle 2 at t to be and the vehicle behind the vehicle 2 cooperatively slows down;

[0114] If the intersection of the two acceleration ranges is not empty, the acceleration of the vehicle 2 is regulated to be in the intersection to ensure the safety of the vehicle 2 and the front and rear vehicles, and if the intersection is empty, the safety of the vehicle 2 and the vehicle 3 is ensured while the rear vehicle cooperatively slows down.

[0115] Step 9, regulating the speed of the vehicle in front of the vehicle 2;

[0116] Step 9.1, calculating the critical value of the acceleration of the vehicle 3 at t+Δt using formula (12) to make the vehicle 2 and the vehicle 3 have the safe TTC at t+Δt

[0117]

[0118] Calculate the acceleration range of vehicle 3 when vehicle 2 and vehicle 3 are safe

[0119] Step 9.2, calculate the acceleration threshold of vehicle 3 when vehicle 3 and vehicle 4 are in the safe collision time threshold at t+Δt using formula (13)

[0120]

[0121] Calculate the acceleration range of vehicle 3 when vehicle 2 and vehicle 3 are safe

[0122] Step 9.3, judge If it is true, then after regulating the acceleration of vehicle 3 in the range of at t time, enter step 10; otherwise, regulate the acceleration of vehicle 3 to at t time, and the front vehicle of vehicle 3 cooperates to accelerate, enter step 10;

[0123] If the intersection of the two acceleration ranges is not empty, regulate the acceleration of vehicle 3 in the intersection to ensure the safety of vehicle 3 and the front and rear vehicles, and if the intersection is empty, ensure the safety of vehicle 2 and vehicle 3 while the front vehicle cooperates to accelerate.

[0124] Step 10, assign t+Δt to t, judge whether t≥T is true, if true, end the control process; otherwise, return to step 2 and execute sequentially, T represents the total control time.

[0125] In this embodiment, an electronic device includes a memory for storing a program supporting a processor to execute the above-mentioned curved road traffic safety discrimination and control method, and the processor is configured to execute the program stored in the memory.

[0126] In this embodiment, a computer readable storage medium stores a computer program on the computer readable storage medium, and the computer program is run by the processor to execute the steps of the above-mentioned curved road traffic safety discrimination and control method.

Claims

1. A method for determining and controlling traffic safety on curves in a connected environment, characterized in that, The motor vehicles in the connected environment are all connected autonomous vehicles; the roads in the connected autonomous vehicles in the connected environment are one-way curved road sections; the method for judging and controlling traffic safety on curved roads includes the following steps: Step 1: Define the target vehicle traveling on the curved road section as vehicle 2, the first vehicle behind vehicle 2 as vehicle 1, and the two vehicles in front of vehicle 2 as vehicle 3 and vehicle 4 respectively, according to their distance from vehicle 2 from closest to farthest. A Cartesian coordinate system is established with the intersection of the starting line of the curved road segment and the center line of the road as the origin, the direction of travel of vehicles on the straight section upstream of the curved road segment as the positive x-axis, and the direction perpendicular to the x-axis and pointing to the inside of the curve as the positive y-axis. Data collection using roadside intelligent transportation equipment The speed of vehicle m at time m acceleration Heading angle x-coordinate of position and position ordinate Where m = 1, 2, 3, 4; make This is the update time interval; Step 2: Plan the following path for vehicle j, where j = 1, 2, 3; Step 2.1: Construct the car-following path function for vehicle j using equation (1); (1) In equation (1), and These represent the x-coordinate and y-coordinate of vehicle j, respectively. , , , These represent the four parameters in the car-following path function for the j-th vehicle; Step 2.2: Solve for the four parameters in equation (1) using equation (2); (2) In equation (2), and Let x and y represent the x and y coordinates of vehicle j at time t, respectively. and Let x and y represent the x-coordinate and y-coordinate of vehicle j+1 at time t, respectively. and Let represent the heading angles of vehicle j and vehicle j+1 at time t, respectively; Step 3: Calculate the collision time between vehicle j and vehicle j+1 at time t. ; Step 3.1: Calculate the arc distance between vehicle j and vehicle j+1 at time t using equation (3). ; (3) In equation (3), This represents the length of vehicle j. This represents the length of vehicle j+1. express The first derivative; Step 3.2: Calculate the collision time between vehicle j and vehicle j+1 at time t using equation (4). ; (4) In equation (4), Indicates the safe collision time threshold. express The speed of vehicle j at time j express The speed of vehicle j+1 at time; Step 4: Calculate the rate of change of collision time between vehicle 2 and vehicle 3 at time t. ; Step 5: If equation (9) is satisfied, it means that vehicle 2 and vehicle 3 are in a safe driving state at time t, and proceed to step 10; otherwise, proceed to step 6. (9) Step 6, if and If , it means that at time t, vehicles 2 and 3 are in a low-risk driving state. After issuing a driving safety reminder to vehicles 2 and 3, proceed to step 10. like and If , it means that at time t, vehicles 2 and 3 are in a medium-risk driving state, and after issuing a driving safety warning to vehicles 2 and 3, proceed to step 10. like and If , it means that at time t, vehicles 2 and 3 are in a high-risk driving state. After issuing a driving safety warning to vehicles 2 and 3, proceed to step 7. Step 7, Judgment Check if the condition is met. If it is met, proceed to step 8; otherwise, proceed to step 9. Step 8: After adjusting the speed of the vehicle behind vehicle 3, proceed to step 10; Step 9: After adjusting the speed of the vehicle in front of vehicle 2, proceed to step 10; Step 10, Assign to ,judge If the condition is met, the control process ends; otherwise, return to step 2 and execute sequentially. T represents the total control duration.

2. The method for determining and controlling traffic safety on curves in a connected environment according to claim 1, characterized in that, Step 4 includes: Step 4.1: Use equation (5) to calculate the distance between vehicle 2 and vehicle 3. Speed ​​of time and ; (5) Step 4.2: Use equation (6) to calculate the distances between vehicles 2 and 3. arrive Displacement within a time interval and ; (6) Step 4.3: Use equation (7) to calculate the distance between vehicle 2 and vehicle 3. Collision time of moments ; (7) Step 4.4: Calculate the rate of change of collision time between vehicle 2 and vehicle 3 at time t using equation (8). ; (8)。 3. The method for determining and controlling traffic safety on curves in a connected environment according to claim 2, characterized in that, Step 8 includes: Step 8.1: Use equation (10) to calculate the distance between vehicle 2 and vehicle 3. The critical acceleration value of vehicle 2 when it is always within the safe collision time threshold ; (10) Step 8.2: Use equation (11) to calculate the distance between vehicle 1 and vehicle 2. The critical acceleration value of vehicle 2 when it is always within the safe collision time threshold. ; (11) Step 8.3, Judgment If true, then at time t, the acceleration of vehicle 2 is adjusted. Once within the range, proceed to step 10; otherwise, adjust the acceleration of vehicle 2 at time t to... After the vehicles behind vehicle 2 decelerate in coordination, proceed to step 10.

4. The method for determining and controlling traffic safety on curves in a connected environment according to claim 3, characterized in that, Step 9 includes: Step 9.1: Use equation (12) to calculate the distance between vehicle 2 and vehicle 3. The critical acceleration value of vehicle 3 when it is always within the safe collision time threshold ; (12) Step 9.2: Use equation (13) to calculate how vehicles 3 and 4 are in... The critical acceleration value of vehicle 3 when it is always within the safe collision time threshold ; (13) Step 9.3, Judgment If true, then at time t, the acceleration of vehicle 3 is adjusted. Once within the range, proceed to step 10; otherwise, adjust the acceleration of vehicle 3 at time t to... After the vehicle in front of vehicle 3 accelerates in coordination, proceed to step 10.

5. An electronic device, comprising a memory and a processor, characterized in that, The memory is used to store programs that support the processor in executing any of the curve traffic safety judgment and control methods according to claims 1-4, and the processor is configured to execute the programs stored in the memory.

6. A computer-readable storage medium storing a computer program thereon, characterized in that, When the computer program is run by the processor, it executes the steps of any one of the curve traffic safety judgment and control methods described in claims 1-4.

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