A terrain-based following distance control method, a terminal device, and a storage medium

Abstract

The present application relates to a kind of terrain-based follow car distance control method, terminal equipment and storage medium.The method includes the following steps: S1.currently driving road's slope θ is dynamically obtained;S2.dynamically follow car distance d is calculated according to slope θ, specific process is as follows: when θ=0, d=d0;When θ≠0 and uphill, when θ≠0 and downhill, S3.judge whether d is in the acceptable follow car distance range [d1,d2], if yes, control the follow car distance of vehicle as d, otherwise, enter S4;S4.if d is less than d1, then control the follow car distance of vehicle as d1;If d is greater than d2, then control follow car distance as d2.The method of the present application can automatically adjust follow car distance according to terrain, reach the consistency of energy saving and safety.

Description

Technical Field

[0001] This invention relates to the field of vehicle distance control technology, and more specifically to a terrain-based following distance control method, terminal device, and storage medium. Background Technology

[0002] Controlling following vehicles, or multiple vehicles traveling in a convoy, benefits from the "wind-breaking" effect of the leading vehicle, reducing air resistance for following vehicles and thus improving fuel efficiency. Current following control systems are generally based on ACC (Adaptive Cruise Control), which uses radar or video to detect the distance to the vehicle ahead and maintain that distance. In practical applications, the appropriate distance is closely related to fuel efficiency. A close distance reduces wind resistance but shortens braking distance, posing a risk of rear-end collisions when the vehicle ahead brakes; a large distance, while safer, weakens the wind-breaking effect of the leading vehicle, resulting in lower fuel efficiency and making it easier for other vehicles to cut in on actual roads, leading to wasted braking energy. Therefore, ACC-controlled following requires calculating a reasonable distance range.

[0003] For heavy-duty trucks, due to their large total mass, braking control varies significantly across different terrains. For example, when going uphill on a steep slope, the braking distance is much shorter because the component of gravity acts in the opposite direction of motion; while when going downhill, braking is more difficult and the braking distance is longer because the component of gravity is superimposed on the direction of motion. Therefore, for heavy-duty trucks, the following distance must also vary depending on the terrain to achieve a balance between fuel efficiency and safety. Traditional methods generally only consider how to maintain a constant following distance, without designing dynamic following distance control methods tailored to different terrains, thus lacking fuel efficiency and safety performance matched to different terrains. Summary of the Invention

[0004] This invention aims to provide a terrain-based following distance control method, terminal device, and storage medium to solve the aforementioned problems. The specific technical solution adopted by this invention is as follows:

[0005] According to one aspect of the present invention, a terrain-based following distance control method is provided, comprising the following steps:

[0006] S1. Dynamically obtain the slope θ of the current driving road;

[0007] S2. Calculate the dynamic following distance d based on the slope θ, the specific process is as follows:

[0008] When θ = 0, d = d0;

[0009] When θ≠0 and the slope is uphill

[0010] When θ≠0 and the slope is downhill

[0011] Where d0 is the traditional ACC following distance, m is the total mass of the vehicle, and g is the acceleration due to gravity. The frontal drag is the drag coefficient of the vehicle in front, H is the frontal area of ​​the car, and V is the frontal drag coefficient. a For the wind speed, a lsq b lsq It is an empirical coefficient;

[0012] S3. Determine whether d is within the acceptable following distance range [d1, d2]. If so, control the following distance of the vehicle to d; otherwise, proceed to S4. Here, d1 indicates that the following distance is less than d1 at the current speed, which may lead to a rear-end collision risk. d2 indicates that the following distance is greater than d2 at the current speed, and the following vehicle and the vehicle in front cannot be considered as following each other.

[0013] S4. If d is less than d1, then control the following distance of the vehicle to be d1; if d is greater than d2, then control the following distance to be d2.

[0014] Furthermore, the slope θ is dynamically acquired through sensors or an electronic horizon system installed on the vehicle.

[0015] Furthermore, d2 is equal to 2 to 3 times d1.

[0016] Furthermore, the method further includes step S0: initializing parameters d0, d1, d2, m, H, V a a lsq b lsq .

[0017] According to another aspect of the present invention, a terminal device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0018] According to another aspect of the present invention, a computer-readable storage medium is also provided, the computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the method described above.

[0019] The present invention adopts the above technical solution and has the following beneficial effects: the method of the present invention can automatically and dynamically adjust the following distance according to the terrain, so as to achieve the consistency of energy saving and safety. Attached Figure Description

[0020] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0021] Figure 1 This is a flowchart of a terrain-based following distance control method according to the present invention. Detailed Implementation

[0022] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0023] Assuming the traditional ACC following distance range is d0, the possible fluctuation range is [d1,d2], where d0∈[d1,d2]. The lower limit d1 indicates that at the current speed, a following distance less than d1 may result in a rear-end collision risk. d1 can be obtained based on the well-known critical rear-end collision distance calculation method. The upper limit d2 means that if the following distance is greater than d2, the following vehicle cannot be considered as following the vehicle in front. Generally, it is taken as 2 to 3 times the value of d1 based on experience.

[0024] According to the paper "Multi-objective control of heterogeneous platoons of pure electric commercial vehicles" (Wang Xuetong, Luo Yugong, Jiang Fachao, Yu Jie, *Automotive Engineering*, 2020, 42(4):505-512), the following wind resistance is:

[0025]

[0026] Where d is the following distance. It is the wind resistance of the car in front, a lsq b lsq It is an empirical coefficient and can be set as a constant.

[0027] When driving on a flat road, maintain a following distance d = d0. When driving uphill, gravity exerts an additional reverse braking force on the vehicle, resulting in a shorter braking distance. Therefore, controlling the following distance to decrease not only does not affect safety but also, according to formula (1), reduces wind resistance due to the reduced distance d, thus improving energy efficiency. Assuming the absolute slope is θ, the total mass of the vehicle is m, and g is the acceleration due to gravity, the following distance is calculated as follows:

[0028] Ensure braking performance is comparable to that on flat roads when driving uphill. That is, the counterforce of gravity equals the reduction in wind resistance.

[0029]

[0030] represents the drag coefficient at the following distance d0 on a flat road, represents the drag coefficient at the following distance d on an uphill road. H is the frontal area of the automobile, V a is the oncoming wind speed, including the forward speed of the vehicle and the current external wind speed, which can be approximately equal to the vehicle speed.

[0031] Substituting Equation (1) into Equation (2), the following distance during uphill driving can thus be obtained as:

[0032]

[0033] At this time, the following distance d < d0, which reduces the distance, lowers the wind resistance, improves energy efficiency, and the reduced wind resistance counteracts the reverse gravity caused by the slope. The braking capacity and braking distance of the vehicle are the same as those on a flat road, so no excessive impact will be exerted on the braking control of the vehicle when the following distance is d, and safety is also ensured.

[0034] Similarly, when driving downhill, due to the longer braking distance, the following distance is controlled to increase, which can ensure safety. Assuming the downhill gradient is θ, the total mass of the vehicle is m, g is the acceleration of gravity, the calculation method of the following distance is as follows:

[0035] It is ensured that the braking performance during downhill driving is equivalent to that on a flat road. That is, the superposition of gravity on the driving force is equal to the increase in wind resistance:

[0036] represents the drag coefficient at the following distance d0 on a flat road, represents the drag coefficient at the following distance d on a downhill road. H is the frontal area of the automobile, Va is the oncoming wind speed, including the forward speed of the vehicle and the current external wind speed, which can be approximately equal to the vehicle speed.

[0037] Thus, the following distance during downhill driving can be obtained as:

[0038] At this time, the following distance d > d0, the increased distance makes the increased wind resistance counteract the driving force superimposed by the slope, the braking capacity and braking distance of the vehicle are the same as those on a flat road, so safety problems caused by deteriorated braking performance during downhill driving will not occur.

[0039] In summary, as shown in Figure 1 , a terrain-based following distance control method of the present invention may comprise the following steps:

[0040] S1: When the vehicle is driving while following another vehicle, the current gradient θ of the traveling road is continuously obtained from a sensor or an electronic horizon system.

[0041] S2: Calculate the dynamic following distance d according to the gradient θ, and the specific process is as follows:

[0042] When θ = 0, the following distance remains the same as the original ACC function distance d0;

[0043] When the slope θ is not 0, if it is uphill, substitute the slope θ into formula (3) to calculate the dynamic following distance d; if it is downhill, substitute the slope θ into formula (4) to calculate the dynamic following distance d.

[0044] S3: Determine whether d is within the acceptable following distance range [d1, d2]. If so, control the following distance of the vehicle to d; otherwise, proceed to step S4.

[0045] S4: If d is less than d1, then control the following distance to d1; if d is greater than d2, then control the following distance to d2.

[0046] Furthermore, the method also includes step S0: initializing parameters d0, d1, d2, m, H, V a a lsq b lsq That is, these parameters need to be set before calculating the following distance. For a certain type of vehicle, the parameters d0, d1, d2, and a lsq b lsq Basically, it remains unchanged, while the parameter m, H, V a Configure according to the actual situation.

[0047] It should be noted that the method of the present invention is more suitable for following distance control of heavy trucks, and can improve energy efficiency while ensuring safety.

[0048] In an embodiment of the present invention, a terminal device is also provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement steps S1-S4 of the method described above.

[0049] Furthermore, the terminal device can be a desktop computer, laptop, handheld computer, or cloud server, etc. The terminal device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above-described structure of the terminal device is merely an example and does not constitute a limitation on the terminal device. It may include more or fewer components than described above, or combine certain components, or different components. For example, the terminal device may also include input / output devices, network access devices, buses, etc., and the embodiments of the present invention do not limit this.

[0050] Furthermore, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. This processor is the control center of the terminal device, connecting all parts of the terminal device via various interfaces and lines.

[0051] The memory can be used to store the computer programs and / or modules. The processor performs various functions by running or executing the computer programs and / or modules stored in the memory and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area, wherein the program storage area may store the operating system, at least one application program required for a function, etc. In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0052] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements steps S1-S4 of the method described in this invention.

[0053] If the modules / units integrated into the terminal device are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the present invention can implement all or part of the processes in steps S1-S4 of the above embodiments by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above-described method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content contained in the computer-readable medium may be appropriately added to or subtracted from the content as required by the legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium may not include electrical carrier signals and telecommunication signals.

[0054] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A terrain-based following distance control method, characterized in that, Includes the following steps: S1. Dynamically obtain the slope θ of the current driving road; S2. Calculate the dynamic following distance d based on the slope θ described in step S1; wherein, calculating the dynamic following distance d based on the slope θ includes: When θ=0, d=d0; When θ≠0 and the slope is uphill ; When θ≠0 and the slope is downhill ; Where d0 is the traditional ACC following distance, m is the total mass of the vehicle, and g is the acceleration due to gravity. The frontal drag is the drag coefficient of the vehicle in front, H is the frontal area of ​​the car, and V is the frontal drag coefficient. a To meet the wind speed, , It is an empirical coefficient; S3. Determine whether d in step S2 is within the acceptable following distance range [d1, d2]. If so, control the following distance of the vehicle to d; otherwise, proceed to step S4. Wherein, d1 indicates that a following distance less than d1 at the current speed may cause a rear-end collision risk, and d2 indicates that a following distance greater than d2 at the current speed means that the following vehicle and the vehicle in front cannot be considered as following each other. S4. If d is less than d1, then control the following distance of the vehicle to be d1; if d is greater than d2, then control the following distance to be d2.

2. The method as described in claim 1, characterized in that, The slope θ mentioned in step S1 is dynamically obtained through sensors or an electronic horizon system installed on the vehicle.

3. The method as described in claim 1, characterized in that, In step S3, d2 is equal to 2 to 3 times d1.

4. The method as described in claim 1, characterized in that, The method further includes step S0: initializing parameters d0, d1, d2, m, H, V a、 , .

5. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1-4.

6. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1-4.

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