Turning vehicle speed regulation and control method considering view limitation

Abstract

The invention discloses an automatic driving vehicle turning speed regulation and control method taking view limitation into consideration. The method comprises the steps that 1, the length of a straight road section, influencing a vehicle, of the upstream of an inflection point is calculated; 2, acquiring the distance between the vehicle and the bending point; 3, calculating the free flow speed of the vehicle; 4, calculating the acceleration which only considers the view limitation of the curve; 5, calculating the acceleration which only considers the front vehicle; 6, the vehicle speed is regulated and controlled according to the front traffic condition; and 7, circulating the steps until the control time is over. According to the invention, the speed of a turning vehicle can be adjusted in real time according to the radius of the curve and the traffic condition of the road ahead before entering the curve, so that the vehicle can keep a reasonable turning speed when the view of the vehicle is limited, the vehicle can be braked in time when danger is found ahead, and the running safety of the vehicle on the curve is improved.

Description

Technical Field

[0001] The present invention belongs to the field of connected vehicle traffic control, and specifically relates to a method for regulating the turning speed of an autonomous vehicle considering vision limitations. Background Art

[0002] Curved road sections are an important part of road traffic. Due to the special linear design of curved road sections, the driving stability of vehicles is reduced compared to straight driving, making them prone to traffic accidents and congestion.

[0003] With the development of autonomous driving technology, new ideas have been brought to solve traffic problems. Compared with human-driven vehicles, autonomous vehicles can drive with a shorter headway, faster reaction speed, and more sensible driving behavior. In previous vehicle following safety studies, the focus has mainly been on vehicle following in straight driving. However, in real driving behavior, there are a large number of curved following behaviors. Compared with the straight driving scenario, in the curved scenario, due to the limitation of geometric alignment, the vehicle's sight distance is affected, resulting in the possible loss of the leading vehicle within the sight distance, which brings difficulties to the vehicle's motion decision-making. Moreover, there are unknown traffic conditions in the vision blind area outside the sight distance, which also increases the safety hazards of vehicles running on curves. Summary of the Invention

[0004] The present invention overcomes the deficiencies of the prior art and proposes a method for regulating the turning speed of an autonomous vehicle considering vision limitations, aiming to adjust the speed in real time according to the vehicle ahead and the sight distance before the vehicle enters curves with different radii, so that the vehicle can turn at a more reasonable speed, and thus can brake or take evasive measures in time when a danger suddenly appears within the vision, thereby reducing the driving risk of the vehicle on curves.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for regulating the turning speed of an autonomous vehicle considering vision limitations according to the present invention is characterized in that it is applied to a one-way traffic section including a curve and includes the following steps:

[0007] Step 1: Define any autonomous vehicle that has not entered the curve ahead on the one-way traffic section as target vehicle A, and the speed of target vehicle A at time t is , and the acceleration at time t is ; Let be the update time interval;

[0008] Step 2: Use Equation (1) to calculate the length of the straight section that affects the driving of vehicle A upstream of the curve entry point at time t ;

[0009] (1)

[0010] In formula (1), T represents the safe following distance; b represents the comfortable acceleration when the target vehicle A decelerates.

[0011] Step 3: Use the in-vehicle navigation to obtain the distance between the target vehicle A and the entrance point of the upcoming curve at time t ;

[0012] Step 4: Use formula (2) to calculate the free-flow speed of the target vehicle A at time t ;

[0013] (2)

[0014] In formula (2), represents the speed limit value of the one-way traffic section, u represents the road friction coefficient, i represents the superelevation of the curve, g represents the acceleration due to gravity, and R represents the radius of the upcoming curve;

[0015] Step 5: Use formula (3) to calculate the acceleration of the target vehicle A considering only the curve vision limit at time t ;

[0016] (3)

[0017] In formula (3), represents the maximum acceleration of the target vehicle A, represents the minimum safe distance between vehicles, represents the maximum distance that the target vehicle A can detect under the curve vision limit at time t;

[0018] Step 6: Determine whether there is a vehicle in front of the target vehicle A within the forward detection range at time t. If so, mark the vehicle in front as vehicle B and proceed to Step 7; otherwise, control the target vehicle A to accelerate at and proceed to Step 10;

[0019] Step 7: Use formula (4) to calculate the acceleration of the target vehicle A considering only the vehicle B in front ;

[0020] (4)

[0021] In formula (4), represents the speed difference between the target vehicle A and vehicle B, represents the distance between the target vehicle A and vehicle B, represents the speed of vehicle B at time t;

[0022] Step 8: Determine whether holds. If it holds, control the target vehicle A to accelerate at Drive and enter step 10; otherwise, enter step 9;

[0023] Step 9: Regulate the acceleration of target vehicle A at time t considering the bend vision limit and the influence of the vehicle in front. and enter step 10;

[0024] Step 10: Assign to , and judge whether holds. If it holds, end the regulation process; otherwise, return to step 2 and execute sequentially. represents the total regulation duration.

[0025] Another feature of the bend speed regulation method for an autonomous vehicle considering vision limit according to the present invention is that step 9 includes:

[0026] Step 9.1: Calculate the weight parameter at time t using formula (5) ;

[0027] (5)

[0028] In formula (5), and are two adjustment parameters and are positive numbers;

[0029] Step 9.2: Calculate the acceleration of target vehicle A at time t considering the bend vision limit and the influence of the vehicle in front using formula (6) ;

[0030] (6)

[0031] Step 9.3: Regulate target vehicle A to drive at acceleration at time t and enter step 10.

[0032] A feature of an electronic device according to the present invention, which includes a memory and a processor, is that the memory is used to store a program that supports the processor to execute the bend vehicle speed regulation method, and the processor is configured to execute the program stored in the memory.

[0033] A feature of a computer-readable storage medium according to the present invention, on which a computer program is stored, is that the computer program executes the steps of the bend vehicle speed regulation method when run by a processor.

[0034] Compared with the prior art, the beneficial technical effects of the present invention are reflected in:

[0035] 1. The present invention establishes a car-following model considering vision limitations, which enables a vehicle to adjust its speed in real time according to the vehicle's line of sight range when there is no vehicle in front, thereby increasing the scenario applicability of autonomous driving technology.

[0036] 2. Compared with the prior art, the present invention considers the influence degree of curves on vehicle speed in different situations based on the curve radius and the distance between the vehicle and the curve entry point.

[0037] 3. Compared with the prior art, when the vehicle is within the influence range of a curve and there is a target vehicle in front within the field of vision, the present invention fully considers the influence of the curve and the vehicle in front, and uses a transition function to adjust the weight parameter between the two, so that the speed change of the vehicle is smoother. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is the overall flowchart of the present invention;

[0039] Figure 2 is the flowchart of the decision-making method of the present invention;

[0040] Figure 3 is the scenario schematic diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0041] In this embodiment, a method for regulating the speed of a turning vehicle considering vision limitations, as Figure 1 shown, is applied to a one-way traffic section including a curve, and includes the following steps:

[0042] Step 1: As Figure 3 shown, define any autonomous vehicle that has not entered the upcoming curve on the one-way traffic section as target vehicle A, the speed of target vehicle A at time t is , and the acceleration at time t is ; let be the update time interval;

[0043] Step 2: As Figure 2 shown, calculate the range of influence of the upcoming curve on vehicle A according to the current driving speed of vehicle A; that is, use Equation (1) to calculate the length of the straight-line section upstream of the curve entry point that affects the driving of vehicle A at time t ;

[0044] (1)

[0045] In Equation (1), T represents the safe following time interval; b represents the comfortable acceleration when target vehicle A decelerates;

[0046] Step 3: Use in-vehicle navigation to obtain the distance between target vehicle A and the upcoming curve entry point at time t.

[0047] Step 4: Calculate the free flow speed of the target vehicle A at time t using Equation (2) ;

[0048] (2)

[0049] In Equation (2), represents the speed limit value of the one-way traffic section, u represents the road friction coefficient, i represents the superelevation of the curve, g represents the acceleration due to gravity, and R represents the radius of the upcoming curve;

[0050] Determine the maximum driving speed of the vehicle according to whether the upcoming curve affects the vehicle. If the curve does not affect vehicle A, the maximum driving speed of the vehicle is the road speed limit value; otherwise, the maximum driving speed is the maximum speed to prevent the vehicle from rolling over;

[0051] Step 5: Generate the acceleration considering only the line of sight using the modified IDM car-following model according to the line of sight of the vehicle; thus, calculate the acceleration of the target vehicle A at time t considering only the line-of-sight restriction of the upcoming curve using Equation (3) ;

[0052] (3)

[0053] In Equation (3), represents the maximum acceleration of the target vehicle A, represents the minimum safe distance between vehicles, represents the maximum distance that the target vehicle A can detect under the line-of-sight restriction of the upcoming curve at time t.

[0054] Step 6: Adopt different acceleration strategies according to whether there is a vehicle in front of vehicle A within the forward field of view; determine whether there is a vehicle in front of the target vehicle A within the forward detection range at time t. If so, mark the vehicle in front as vehicle B and proceed to Step 7; otherwise, as Figure 3 shown in part c of, there is no vehicle in front of vehicle A, then the speed regulation of vehicle A only needs to consider the line-of-sight restriction of the curve; that is, regulate the target vehicle A to accelerate at and proceed to Step 10;

[0055] Step 7: As Figure 3 shown in part a of, there is a vehicle in front of vehicle A and it has not entered the influence range of the curve, then the speed regulation of vehicle A only needs to consider the vehicle in front; that is, calculate the acceleration of the target vehicle A at time t considering only the vehicle B in front using Equation (4) ;

[0056] (4)

[0057] In Equation (4), represents the speed difference between the target vehicle A and vehicle B, represents the distance between the target vehicle A and vehicle B, represents the speed of vehicle B at time t;

[0058] Step 8, determine Whether it holds. If it holds, adjust the target vehicle A to accelerate at and enter Step 10; otherwise, enter Step 9;

[0059] Step 9, adjust the acceleration of the target vehicle A at time t considering the curve vision limitation and the influence of the preceding vehicle;

[0060] Step 9.1, calculate the weight parameter at time t using Equation (5) ; so that when vehicle A loses the vision of the preceding vehicle due to the curve alignment limitation and the following state of vehicle A changes, the speed of vehicle A is smoother, improving the comfort of the vehicle;

[0061] (5)

[0062] In Equation (5), and are two adjustment parameters and are positive numbers;

[0063] Step 9.2, calculate the acceleration of the target vehicle A at time t considering the curve vision limitation and the influence of the preceding vehicle using Equation (6) ;

[0064] (6)

[0065] Step 9.3, as shown in part b of Figure 3 , there is a preceding vehicle in front of vehicle A and it enters the influence range of the curve, then the speed adjustment of vehicle A needs to consider both the preceding vehicle and the curve vision limitation; thus, adjust the target vehicle A to accelerate at and enter Step 10;

[0066] Step 10, assign to , determine whether holds. If it holds, end the adjustment process; otherwise, return to Step 2 and execute sequentially, represents the total adjustment duration.

[0067] An electronic device, including a memory and a processor. The memory is used to store a program that supports the processor to execute the above method for adjusting the speed of a vehicle turning, and the processor is configured to execute the program stored in the memory.

[0068] A computer-readable storage medium has a computer program stored thereon. When the computer program is run by a processor, it executes the steps of the above-described method for regulating the speed of a turning vehicle.

Claims

1. A method for controlling the cornering speed of an autonomous driving vehicle taking into account field of view limitations, characterized in that: It is applied to one-way traffic sections with curves and includes the following steps: Step 1: Define any autonomous driving vehicle on a one-way road section that has not entered the curve ahead as the target vehicle A. The speed of the target vehicle A at time t is , the acceleration at time t is ;make is the update interval; Step 2: Use formula (1) to calculate the length of the straight section upstream of the turning point that affects the driving of vehicle A at time t: ; (1) In formula (1), T represents the safe following distance; b represents the comfortable acceleration of the target vehicle A when it decelerates; Step 3: Use the vehicle navigation system to obtain the distance between the target vehicle A and the curve point ahead at time t ; Step 4: Calculate the free flow speed of target vehicle A at time t using formula (2): ; (2) In formula (2), Indicates the speed limit of a one-way road section, u indicates the road friction coefficient, i indicates the superelevation of the curve, g indicates the acceleration of gravity, and R indicates the radius of the curve ahead; Step 5: Use formula (3) to calculate the acceleration of the target vehicle A at time t, considering only the curve field of view limitation: ; (3) In formula (3), represents the maximum acceleration of the target vehicle A, Indicates the minimum safe distance between vehicles. It represents the maximum distance that the target vehicle A can detect at time t under the limitation of the front curve field of view; Step 6: Determine whether there is a preceding vehicle in the detection range ahead of target vehicle A at time t. If so, record the preceding vehicle as vehicle B and proceed to step 7; otherwise, control target vehicle A at time t to accelerate Drive and go to step 10; Step 7: Use equation (4) to calculate the acceleration of the target vehicle A at time t, considering only the front vehicle B. ; (4) In formula (4), represents the speed difference between the target vehicle A and vehicle B, Indicates the distance between target vehicle A and vehicle B, represents the speed of vehicle B at time t; Step 8: Judgement Is it true? If true, then control the target vehicle A to accelerate Drive and go to step 10; otherwise, go to step 9; Step 9: Control the acceleration of the target vehicle A at time t, taking into account the limitation of the curve vision and the influence of the preceding vehicle. , and go to step 10; Step 10: Assign to ,judge Is it true? If so, end the control process; otherwise, return to step 2 and execute sequentially. Indicates the total control time.

2. The method for controlling the cornering speed of an autonomous driving vehicle considering field of view limitation according to claim 1, characterized in that: The step 9 comprises: Step 9.1: Calculate the weight parameter at time t using formula (5): ; (5) In formula (5), and are 2 adjustment parameters and are positive; Step 9.2: Use equation (6) to calculate the acceleration of the target vehicle A at time t, taking into account the curving field of view limitation and the influence of the preceding vehicle: ; (6) Step 9.3: Control the target vehicle A at time t with acceleration Drive and go to step 10.

3. An electronic device, comprising a memory and a processor, characterized in that: The memory is used to store a program that supports the processor to execute the method for controlling the speed of a vehicle turning as described in claim 1 or 2, and the processor is configured to execute the program stored in the memory.

4. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for controlling the speed of a vehicle turning according to claim 1 or 2 are executed.

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