Speed ​​planning algorithm and device for passenger cars

Abstract

The present invention relates to a speed planning algorithm and device for passenger buses. The algorithm comprises the following steps: determining a maximum speed and an intermediate speed; if the intermediate speed is greater than or equal to the maximum speed, comparing the current speed with the maximum speed; if the current speed is greater than or equal to the maximum speed, then decelerating to the maximum speed in the first half and then driving at a constant speed; and decelerating to the platform speed in the second half and then driving at a constant speed; if the current speed is less than or equal to the maximum speed, then accelerating to the maximum speed in the first half and then driving at a constant speed; and decelerating to the platform speed in the second half and then driving at a constant speed; if the intermediate speed is less than or equal to the maximum speed, then comparing the intermediate speed with the platform speed; and if the intermediate speed is greater than or equal to the platform speed, then accelerating to the intermediate speed in the first half and then driving at a constant speed; and decelerating to the platform speed in the second half and then driving at a constant speed; and if the intermediate speed is less than or equal to the platform speed, then accelerating to the intermediate speed in the first half and then driving at a constant speed; and accelerating to the platform speed in the second half and then driving at a constant speed. The calculation process of the intermediate speed of the present invention is simple, thereby improving planning efficiency.

Description

Technical Field

[0001] The invention relates to a speed planning algorithm and device for a passenger car, belonging to the technical field of speed planning. Background Art

[0002] When driving, autonomous vehicles need to plan their speed based on actual road conditions and scenarios so that they can reach their target location quickly, smoothly, safely and accurately.

[0003] Common speed planning algorithms include S-type, exponential, and trapezoidal speed planning. S-type speed planning offers greater acceleration and deceleration control flexibility, but it has many segments and requires a high computational load. Exponential speed planning offers discontinuous acceleration, making it suitable for stepper motor speed control. Trapezoidal speed planning is widely used due to its simplicity, low computational load, and fast response.

[0004] For example, the journal article titled “A trapezoidal speed planning method for intelligent vehicles based on intermediate speeds”, published in Computer Engineering with journal number 1000-3428(201)01-00-0, discloses a trapezoidal speed planning method for intelligent vehicles based on intermediate speeds. This speed planning method incorporates obstacle speed into the vehicle's speed planning process, and uses the proposed intermediate speed as a reference for speed decision control, thereby realizing advance planning of vehicle speed, ensuring the continuity of planning results, improving the smoothness of the planning speed process, and solving the problem of fluctuations in speed planning results when facing dynamic obstacles.

[0005] However, in the above speed planning process, the calculation process of the intermediate speed is complicated, resulting in low planning efficiency. Summary of the Invention

[0006] The purpose of this application is to provide a speed planning algorithm and device for passenger cars to solve the problem of low planning efficiency in existing methods.

[0007] To achieve the above objectives, the present application proposes a technical solution for a speed planning algorithm for a passenger car, comprising the following steps:

[0008] 1) Determine the maximum speed, maximum acceleration, and maximum deceleration for the current road;

[0009] 2) determining the vehicle's intermediate speed on the current road based on the vehicle's current speed, target distance, minimum safe distance, and the maximum acceleration;

[0010] 3) Determine the size of the intermediate speed and the maximum speed. If the intermediate speed is greater than or equal to the maximum speed, use the maximum speed as the speed limit for speed planning and proceed to step 4); if the intermediate speed is less than the maximum speed, use the intermediate speed as the speed limit for speed planning and proceed to step 5);

[0011] 4) Determine the difference between the current speed and the maximum speed. If the current speed is greater than the maximum speed, then in the first half of the target distance, the vehicle decelerates from the current speed to the maximum speed at a first deceleration, and then travels at a constant speed of the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at a second deceleration, and then travels at a constant speed of the platform speed. If the current speed is less than the maximum speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the maximum speed at a first acceleration, and then travels at a constant speed of the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at a third deceleration, and then travels at a constant speed of the platform speed.

[0012] 5) Determine the magnitude of the intermediate speed and the platform speed. If the intermediate speed is greater than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the second acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle decelerates from the intermediate speed to the platform speed using the fourth deceleration, and then travels at a constant speed at the platform speed. If the intermediate speed is less than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the third acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle accelerates from the intermediate speed to the platform speed using the fourth acceleration, and then travels at a constant speed at the platform speed.

[0013] The platform speed is the speed of the obstacle; the first acceleration, the second acceleration, the third acceleration, and the fourth acceleration are all less than the maximum acceleration; and the first deceleration, the second deceleration, the third deceleration, and the fourth deceleration are all less than the maximum deceleration.

[0014] The technical solution of the speed planning algorithm for passenger vehicles of the present invention has the beneficial effect of calculating the intermediate speed of the current road based on the maximum speed and maximum acceleration of the current road, taking into account road conditions. The vehicle's speed limit for the current road is determined based on the magnitude of the intermediate speed and the maximum speed. Trapezoidal speed planning is performed using this speed limit, and segmented planning is performed using the first and second halves of the target distance, enabling the vehicle to safely reach the obstacle in the shortest possible time. The intermediate speed calculation process of the present invention is simple, improving the efficiency of speed planning.

[0015] Furthermore, in step 2), the calculation process of the intermediate speed is:

[0016]

[0017] Among them, V mid is the intermediate speed; a acc_max is the maximum acceleration; s is the target distance; s safe_min is the minimum safety distance; V cur is the current speed.

[0018] Furthermore, roads include straight roads and curved roads.

[0019] Furthermore, on the straight road, the maximum speed is obtained according to road speed limit information.

[0020] Furthermore, on the curved road, the maximum speed is obtained according to road speed limit information; the maximum acceleration is obtained according to the curvature radius; and the maximum deceleration is obtained according to vehicle parameters.

[0021] In addition, the present application also proposes a technical solution for a speed planning device for a passenger car, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor. When executing the computer program, the processor implements the following steps:

[0022] 1) Obtain the maximum speed, maximum acceleration, and maximum deceleration on the current road; also obtain the vehicle's current speed, target distance, and minimum safe distance;

[0023] 2) determining the vehicle's intermediate speed on the current road based on the vehicle's current speed, target distance, minimum safe distance, and the maximum acceleration;

[0024] 3) Determine the size of the intermediate speed and the maximum speed. If the intermediate speed is greater than or equal to the maximum speed, use the maximum speed as the speed limit for speed planning and proceed to step 4); if the intermediate speed is less than the maximum speed, use the intermediate speed as the speed limit for speed planning and proceed to step 5);

[0025] 4) Determine the difference between the current speed and the maximum speed. If the current speed is greater than the maximum speed, then in the first half of the target distance, the vehicle decelerates from the current speed to the maximum speed at a first deceleration, and then travels at a constant speed of the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at a second deceleration, and then travels at a constant speed of the platform speed. If the current speed is less than the maximum speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the maximum speed at a first acceleration, and then travels at a constant speed of the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at a third deceleration, and then travels at a constant speed of the platform speed.

[0026] 5) Determine the magnitude of the intermediate speed and the platform speed. If the intermediate speed is greater than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the second acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle decelerates from the intermediate speed to the platform speed using the fourth deceleration, and then travels at a constant speed at the platform speed. If the intermediate speed is less than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the third acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle accelerates from the intermediate speed to the platform speed using the fourth acceleration, and then travels at a constant speed at the platform speed.

[0027] The platform speed is the speed of the obstacle; the first acceleration, the second acceleration, the third acceleration, and the fourth acceleration are all less than the maximum acceleration; and the first deceleration, the second deceleration, the third deceleration, and the fourth deceleration are all less than the maximum deceleration.

[0028] The beneficial effects of the technical solution of the speed planning device for passenger vehicles of the present invention are as follows: the present invention combines road conditions, obtains the maximum speed and maximum acceleration on the current road, calculates the intermediate speed on the current road, determines the vehicle's speed limit on the current road based on the magnitude of the intermediate speed and the maximum speed, performs trapezoidal speed planning based on the speed limit, and uses the first and second halves of the target distance for segmented planning, allowing the vehicle to safely reach the obstacle in the shortest possible time. The present invention simplifies the calculation process of the intermediate speed, improving the efficiency of speed planning.

[0029] Furthermore, in step 2), the calculation process of the intermediate speed is:

[0030]

[0031] Among them, V mid is the intermediate speed; a acc_max is the maximum acceleration; s is the target distance; s safe_min is the minimum safety distance; V cur is the current speed.

[0032] Furthermore, roads include straight roads and curved roads.

[0033] Furthermore, on the straight road, the maximum speed is obtained according to road speed limit information.

[0034] Furthermore, on the curved road, the maximum speed is obtained according to road speed limit information; the maximum acceleration is obtained according to the curvature radius; and the maximum deceleration is obtained according to vehicle parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1is a flow chart of the speed planning algorithm for passenger cars of the present invention;

[0036] Figure 2 The present invention takes the maximum speed as the speed limit, and the current speed is greater than the maximum speed.

[0037] Figure 3 The present invention takes the maximum speed as the speed limit, and the current speed is less than the maximum speed.

[0038] Figure 4 The present invention is a speed planning curve diagram in which the intermediate speed is the limiting speed and the platform speed is greater than the intermediate speed;

[0039] Figure 5 The present invention takes the intermediate speed as the limiting speed, and the platform speed is less than the intermediate speed.

[0040] Figure 6 It is a structural diagram of the speed planning device for passenger cars according to the present invention. DETAILED DESCRIPTION

[0041] Example of a speed planning algorithm for a passenger car:

[0042] The main concept of the speed planning algorithm for passenger buses is that, based on the problem of complex intermediate speed calculation in the existing technology, the present invention determines the maximum speed, maximum acceleration, and maximum deceleration of the current road, calculates the intermediate speed based on the maximum acceleration, target distance, and the minimum safety distance. By comparing the intermediate speed with the maximum speed, the smaller value is taken as the speed limit of the current road for speed planning, thereby improving planning efficiency.

[0043] Specifically, the speed planning algorithm for buses is as follows: Figure 1 As shown, the following steps are included:

[0044] 1) Determine the maximum speed V on the current road max , maximum acceleration a acc_max , and the maximum deceleration a dec_max .

[0045] In this step, roads include straight roads and curved roads, where:

[0046] On a straight road, the maximum speed V max According to the speed limit information of the road (speed limit information can be obtained through the map), the maximum acceleration a acc_max and maximum deceleration a dec_max The vehicle's own hardware conditions limit the vehicle's own parameters, generally taking the vehicle's own acceleration limit and deceleration limit. Of course, the maximum acceleration a acc_maxIt can also be obtained based on the distance to the obstacle in front and the current speed.

[0047] On a curved road, the minimum turning radius of the vehicle is obtained based on the curvature radius of the current road (curvature radius = 1 / minimum turning radius), and the maximum acceleration a is determined based on the minimum turning radius and the current vehicle speed. acc_max (a acc_max = current speed * current vehicle speed / minimum turning radius); maximum deceleration a dec_max Take the vehicle's own deceleration limit; maximum speed V max Obtained based on the speed limit information of the road.

[0048] Maximum speed V max The speed limit of the vehicle on the current road; the maximum acceleration a acc_max The acceleration limit when the vehicle is accelerating; the maximum deceleration a dec_max The deceleration limit for the vehicle when decelerating; acceleration is a positive number, deceleration is a negative number, and the magnitude of acceleration and deceleration are numerical values, regardless of positive or negative. For example, the deceleration is -10m / s 2 Greater than deceleration of -8m / s 2 When planning the speed, both acceleration and deceleration are within the maximum acceleration a. acc_max and maximum deceleration a dec_max Do not exceed this range.

[0049] 2) According to the current speed V of the vehicle cur , target distance s, minimum safety distance s safe_min , and the maximum acceleration a acc_max Determine the vehicle's median speed V on the current road mid .

[0050] The calculation process is:

[0051] The target distance s is the distance from the vehicle to the obstacle (the obstacle here can be an intersection, a station, a moving vehicle, a moving pedestrian, a stationary obstacle, etc.), ss safe_min It indicates the safe distance that the vehicle can travel. Therefore, the significance of the intermediate speed is that the vehicle accelerates to the speed of half the safe distance at the maximum acceleration under the current speed, ensuring that the vehicle can reach half of the target distance in the shortest time and reach the target speed.

[0052] Minimum safety distance safe_min It is determined by the relative position between the vehicle and the obstacle. If they are traveling in the same direction, the calculation method is s safe_min =V cur 2 / (2a) If it is driving in the reverse direction, the calculation method is s safe_min =(V cur +v obs ) 2 / (2a), V cur (scalar) is the current speed of the vehicle, v obs (scalar) is the obstacle speed, a is the maximum deceleration limit of the vehicle itself, and the maximum deceleration a dec_max same.

[0053] 3) Determine V mid and V max The size of V mid ≥V max , then V max Use the speed limit to plan the speed and go to step 4); if V mid <V max , then V mid Perform speed planning as the speed limit and go to step 5).

[0054] 4) Determine V cur and V max Size:

[0055] like Figure 2 As shown, if V cur >V max , then in the first half of the target distance s, the vehicle decelerates from V cur Decelerate to V max After that, V max Constant speed driving; in the second half of the target distance s, the vehicle decelerates from V max Decelerate to platform speed V flat After that, V flat Constant speed driving; V flat is the speed of the obstacle. If the obstacle is a platform, then V flat =0, if it is a moving vehicle, then V flat is the speed of the moving vehicle;

[0056] like Figure 3 As shown, if V cur <V max , then in the first half of the target distance s, the vehicle accelerates from V cur Accelerate to V max After that, V max Constant speed driving; in the second half of the target distance s, the vehicle moves from V max Deceleration V flat After that, V flat driving at a constant speed;

[0057] Of course, if Vcur =V max , then in the first half of the target distance s, the vehicle moves at V cur Constant speed driving; in the second half of the target distance s, the vehicle moves from V max Deceleration V flat After that, V flat driving at a constant speed;

[0058] All of the above are V flat <V max Therefore, in the second half of the target distance s, the vehicles all decelerate to V flat ; For V flat ≥V max In this case, due to V max To limit the speed, the vehicle is not allowed to exceed the speed. Therefore, corresponding to the above two cases, in the second half of the target distance s, the vehicle directly follows V max Just drive at a constant speed.

[0059] In step 4), the first deceleration, the second deceleration, the first acceleration, and the third deceleration are set according to the following:

[0060] Assume that the vehicle is moving from V cur Decelerate to V max Travel exactly s / 2; then the deceleration is Figure 2 Minimum deceleration a during the first half of deceleration dec_min1 , Therefore, the first deceleration can be a dec_min1 and a dec_max Any value between , which can be set according to actual needs;

[0061] Assume that the vehicle is moving from V max Decelerate to V flat Travel exactly s / 2; then the deceleration is Figure 2 Minimum deceleration a during the middle and latter half of deceleration dec_min2 , Therefore, the second deceleration can be a dec_min2 and a dec_max Any value between , can be set according to actual needs; similarly, the third deceleration can also be a dec_min2 and a dec_max Any value between

[0062] Assume that the vehicle moves from V cur Accelerate to V max Travel exactly s / 2; then the deceleration is Figure 3 Minimum acceleration a during the first half of acceleration acc_min1 , So the first acceleration can be a acc_min1 and a acc_max It can be set to any value between 0 and 1 according to actual needs.

[0063] 5) In V mid <V max In case of combined V mid The calculation process of V cur Will not exceed V mid , so directly judge V mid and V flat Size:

[0064] like Figure 4 As shown, if V mid >V flat , then in the first half of the target distance s, the vehicle accelerates from V cur Accelerate to V mid After that, V mid Constant speed driving; in the second half of the target distance s, the vehicle decelerates from V mid Decelerate to V flat After that, V flat driving at a constant speed;

[0065] like Figure 5 As shown, if V mid <V flat , then in the first half of the target distance s, the vehicle accelerates from V cur Accelerate to V mid After that, V mid Constant speed; in the second half of the target distance s, the vehicle moves from V mid Accelerate to V flat After that, V flat driving at a constant speed;

[0066] Of course, if V mid =V flat , then in the first half of the target distance s, the vehicle accelerates from V cur Accelerate to V mid After that, V mid Constant speed; in the second half of the target distance s, the vehicle moves at V mid Drive at a constant speed.

[0067] In step 5), the second acceleration, the fourth deceleration, the third acceleration, and the fourth acceleration are set according to the following:

[0068] Assume that the vehicle moves from V cur Accelerate to V mid Travel exactly s / 2; then the acceleration is Figure 4 Minimum acceleration a during the first half of accelerationacc_min2 , Combined with the calculation formula of the intermediate speed, we get So the second acceleration can be a acc_min2 and a acc_max Any value between , can be set according to actual needs; similarly, the third acceleration can also be a acc_min2 and a acc_max Any value between

[0069] Assume that the vehicle is moving from V mid Decelerate to V flat Travel exactly s / 2; then the deceleration is Figure 4 Minimum deceleration a during the middle and latter half of deceleration dec_min3 , Therefore, the fourth deceleration can be a dec_min3 and a dec_max Any value between , which can be set according to actual needs;

[0070] Assume that the vehicle moves from V mid Accelerate to V flat Travel exactly s / 2; then the acceleration is Figure 5 Minimum acceleration a during the middle and latter half of acceleration acc_min3 , Therefore, the fourth acceleration can be a acc_min3 and a acc_max It can be set to any value between 0 and 1 according to actual needs.

[0071] In the above embodiment, in order to better meet the actual situation of the road, the maximum speed V max , maximum acceleration a acc_max , and the maximum deceleration a dec_max It is determined according to the road conditions and scenarios. As another implementation method, whether it is a straight road or a curved road, the maximum speed V under different roads can also be directly calibrated based on experience. max , maximum acceleration a acc_max , and the maximum deceleration a dec_max value.

[0072] The present invention calculates the intermediate speed, compares the intermediate speed with the maximum speed, takes the smaller value as the speed limit, and performs trapezoidal speed planning, which can ensure that the vehicle reaches the target point (i.e., obstacle) safely in the shortest time. The trapezoidal speed planning process is a universal process and is applicable to various scenarios such as lane changing, following, regular driving, intersections, entering the station, and obstacle avoidance.

[0073] Example of a speed planning device for a passenger car:

[0074] Speed ​​planning device for passenger cars, such as Figure 6 As shown, the system comprises a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, a speed planning algorithm for a bus is implemented.

[0075] The specific implementation process and effects of the speed planning algorithm for buses are introduced in the above-mentioned embodiment of the speed planning algorithm for buses, and will not be repeated here.

[0076] In other words, the algorithm in the above embodiment of the speed planning algorithm for a passenger vehicle should be understood to be implemented as a process flow of the speed planning algorithm for a passenger vehicle using computer program instructions. These computer program instructions can be provided to a processor (such as a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device), so that the processor executes these instructions to implement the functions specified in the above algorithm flow.

[0077] The processor referred to in this embodiment refers to a processing device such as a microprocessor MCU or a programmable logic device FPGA;

[0078] The memory referred to in this embodiment is used to store computer program instructions for implementing the speed planning algorithm for passenger vehicles, and includes physical devices for storing information, typically digitizing the information and then storing it in electrical, magnetic, or optical media. Examples include various types of memory that use electrical energy to store information, such as RAM and ROM; various types of memory that use magnetic energy to store information, such as hard disks, floppy disks, magnetic tapes, magnetic core memories, bubble memories, and USB flash drives; and various types of memory that use optical energy to store information, such as CDs and DVDs. Of course, other types of memory exist, such as quantum memory and graphene memory.

[0079] The speed planning device for a passenger bus is composed of the memory and processor that store computer program instructions for implementing the speed planning algorithm for the passenger bus. The speed planning device is implemented by the processor executing corresponding program instructions in the computer. The computer can use the Windows operating system, Linux system, or other systems, such as Android and iOS system programming languages, to implement it on a smart terminal, as well as based on the processing logic of a quantum computer.

[0080] As another embodiment, the speed planning device for a bus may further include other processing hardware, such as a database or multi-level cache, a GPU, etc. The present invention does not specifically limit the structure of the speed planning device for a bus.

Claims

1. A speed planning algorithm for passenger cars, characterized in that: The following steps are involved: 1) Determine the maximum speed, maximum acceleration, and maximum deceleration for the current road; 2) According to the current speed V of the vehicle cur , target distance s, minimum safety distance s safe_min , and the maximum acceleration a acc_max Determine the vehicle's median speed V on the current road mid ;Intermediate speed V mid The calculation process is: 3) Determine the size of the intermediate speed and the maximum speed. If the intermediate speed is greater than or equal to the maximum speed, use the maximum speed as the speed limit for speed planning and proceed to step 4); If the intermediate speed is less than the maximum speed, the intermediate speed is used as the speed limit for speed planning and the process goes to step 5); 4) Determine the current speed and the maximum speed. If the current speed is greater than the maximum speed, then in the first half of the target distance, the vehicle decelerates from the current speed to the maximum speed at a first deceleration rate, and then travels at a constant speed at the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at the second deceleration rate, and then travels at a constant speed at the platform speed. If the current speed is less than the maximum speed, in the first half of the target distance, the vehicle accelerates from the current speed to the maximum speed at the first acceleration rate, and then travels at a constant speed at the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at the third deceleration, and then travels at a constant speed at the platform speed; 5) Determine the magnitude of the intermediate speed and the platform speed. If the intermediate speed is greater than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the second acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle decelerates from the intermediate speed to the platform speed using the fourth deceleration, and then travels at a constant speed at the platform speed. If the intermediate speed is less than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the third acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle accelerates from the intermediate speed to the platform speed using the fourth acceleration, and then travels at a constant speed at the platform speed. The platform speed is the speed of the obstacle; the first acceleration, the second acceleration, the third acceleration, and the fourth acceleration are all less than the maximum acceleration; and the first deceleration, the second deceleration, the third deceleration, and the fourth deceleration are all less than the maximum deceleration.

2. The speed planning algorithm for a passenger car according to claim 1, characterized in that: Minimum safety distance safe_min It is determined by the relative position between the vehicle and the obstacle. If they are traveling in the same direction, s safe_min =V cur 2 / (2a dec_max ), if it is driving in the reverse direction, s safe_min =(V cur +v obs ) 2 / (2a dec_max ), v obs is the obstacle speed, a dec_max is the maximum deceleration of the vehicle.

3. The speed planning algorithm for a passenger car according to claim 1, characterized in that: Roads include straight roads and curved roads.

4. The speed planning algorithm for a passenger car according to claim 3, characterized in that: On the straight road, the maximum speed is obtained according to road speed limit information.

5. The speed planning algorithm for a passenger car according to claim 3, characterized in that: On the curved road, the maximum speed is obtained according to road speed limit information; the maximum acceleration is obtained according to the curvature radius; and the maximum deceleration is obtained according to vehicle parameters.

6. A speed planning device for a passenger car, characterized in that: The invention comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the following steps when executing the computer program: 1) Obtain the maximum speed, maximum acceleration, and maximum deceleration on the current road; also obtain the vehicle's current speed, target distance, and minimum safe distance; 2) According to the current speed V of the vehicle cur , target distance s, minimum safety distance s safe_min , and the maximum acceleration a acc_max Determine the vehicle's median speed V on the current road mid ;Intermediate speed V mid The calculation process is: 3) Determine the size of the intermediate speed and the maximum speed. If the intermediate speed is greater than or equal to the maximum speed, use the maximum speed as the speed limit for speed planning and proceed to step 4); If the intermediate speed is less than the maximum speed, the intermediate speed is used as the speed limit for speed planning and the process goes to step 5); 4) Determine the current speed and the maximum speed. If the current speed is greater than the maximum speed, then in the first half of the target distance, the vehicle decelerates from the current speed to the maximum speed at a first deceleration rate, and then travels at a constant speed at the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at the second deceleration rate, and then travels at a constant speed at the platform speed. If the current speed is less than the maximum speed, in the first half of the target distance, the vehicle accelerates from the current speed to the maximum speed at the first acceleration rate, and then travels at a constant speed at the maximum speed. In the second half of the target distance, the vehicle decelerates from the maximum speed to the platform speed at the third deceleration, and then travels at a constant speed at the platform speed; 5) Determine the magnitude of the intermediate speed and the platform speed. If the intermediate speed is greater than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the second acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle decelerates from the intermediate speed to the platform speed using the fourth deceleration, and then travels at a constant speed at the platform speed. If the intermediate speed is less than the platform speed, then in the first half of the target distance, the vehicle accelerates from the current speed to the intermediate speed using the third acceleration, and then travels at a constant speed at the intermediate speed. In the second half of the target distance, the vehicle accelerates from the intermediate speed to the platform speed using the fourth acceleration, and then travels at a constant speed at the platform speed. The platform speed is the speed of the obstacle; the first acceleration, the second acceleration, the third acceleration, and the fourth acceleration are all less than the maximum acceleration; and the first deceleration, the second deceleration, the third deceleration, and the fourth deceleration are all less than the maximum deceleration.

7. The speed planning device for a passenger vehicle according to claim 6, characterized in that: Minimum safety distance safe_min It is determined by the relative position between the vehicle and the obstacle. If they are traveling in the same direction, s safe_min =V cur 2 / (2a dec_max ), if it is driving in the reverse direction, s safe_min =(V cur +v obs ) 2 / (2a dec_max ), v obs is the obstacle speed, a dec_max is the maximum deceleration of the vehicle.

8. The speed planning device for a passenger vehicle according to claim 6, characterized in that: Roads include straight roads and curved roads.

9. The speed planning device for a passenger vehicle according to claim 8, characterized in that: On the straight road, the maximum speed is obtained according to road speed limit information.

10. The speed planning device for a passenger vehicle according to claim 8, characterized in that: On the curved road, the maximum speed is obtained according to road speed limit information; the maximum acceleration is obtained according to the curvature radius; and the maximum deceleration is obtained according to vehicle parameters.

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