Vehicle speed planning method and device, electronic equipment and storage medium

Abstract

A vehicle speed planning method, apparatus, electronic device, and storage medium are disclosed, relating to the field of autonomous driving technology. The method includes: acquiring initial state parameters of the vehicle entering a curve and the vehicle's current turning angle on the curve; calculating a critical turning angle based on the initial state parameters; calculating the vehicle's target speed based on the initial state parameters and the current turning angle when the current turning angle has not reached the critical turning angle; and calculating the maximum passing speed as the vehicle's target speed based on the initial state parameters when the current turning angle reaches the critical turning angle. This solution enables segmented speed planning based on the critical turning angle, performing acceleration planning at the initial stage of the vehicle entering the curve, and maintaining a constant speed at the maximum safe speed after reaching the critical turning angle. This ensures vehicle driving safety and achieves the fastest planning during the turning process, improving traffic efficiency.

Description

Technical Field

[0001] This invention relates to the field of autonomous driving technology, and specifically to a vehicle speed planning method, device, electronic device, and storage medium. Background Technology

[0002] With the advancement of artificial intelligence, autonomous driving technology has been widely applied. Path planning and speed planning are two core components in autonomous driving. Currently, there is no unified theoretical method for speed planning, especially during vehicle cornering. In existing technologies, ordinary vehicles typically employ a uniform speed planning strategy on general curves. While this ensures safety, it sacrifices traffic efficiency and fails to fully utilize the vehicle's dynamic performance. In the field of autonomous racing, although reinforcement learning-based speed planning methods exist, these methods are usually computationally intensive, involve complex model training, and produce uncertain planning results, making it difficult to meet real-time and deterministic control requirements. Furthermore, limit speed planning based on friction circle constraints often involves solving complex differential equations, which are difficult to obtain analytically in the time domain, resulting in high computational complexity and hindering real-time applications of onboard equipment. Therefore, how to achieve maximum speed planning during cornering while preventing vehicle sideslip and reducing computational complexity is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] In view of this, embodiments of this application propose a vehicle speed planning method, apparatus, electronic device, and storage medium to improve the above-mentioned problems.

[0004] According to a first aspect of the embodiments of this application, a vehicle speed planning method is provided, the method comprising: acquiring initial state parameters of a vehicle entering a curve and the current turning angle of the vehicle on the curve; wherein the initial state parameters include an initial speed, a road surface friction coefficient, and a turning radius; calculating a critical turning angle based on the initial state parameters; when the current turning angle has not reached the critical turning angle, calculating a target speed of the vehicle based on the initial state parameters and the current turning angle; and when the current turning angle reaches the critical turning angle, calculating a maximum passing speed as the target speed of the vehicle based on the initial state parameters.

[0005] In some embodiments, calculating the target speed of the vehicle based on the initial state parameters and the current turning angle includes: calculating an angle correction parameter based on the initial speed, the road surface friction coefficient, gravitational acceleration, and the turning radius; calculating a speed function value based on the current turning angle and the angle correction parameter; and calculating the target speed based on the initial speed, the road surface friction coefficient, the turning radius, and the speed function value.

[0006] In some embodiments, calculating the critical turning angle based on the initial state parameters includes: calculating a first angle based on the initial velocity, the road surface friction coefficient, gravitational acceleration, and the turning radius; wherein the first angle is used to indicate the angular offset corresponding to the initial velocity; and calculating the critical turning angle based on a preset angle and the first angle.

[0007] In some embodiments, calculating the maximum passing speed based on the initial state parameters includes: calculating a product based on the road surface friction coefficient, gravitational acceleration, and the turning radius; wherein the product is used to indicate the vehicle's maximum speed constraint value in the curve; and the maximum passing speed is calculated based on the product.

[0008] In some embodiments, obtaining the current turning angle of the vehicle on the curve includes: obtaining the turning distance between the vehicle's current position and its initial position when entering the curve; and calculating the current turning angle based on the turning distance and the turning radius.

[0009] In some embodiments, the method further includes: obtaining the current position of the vehicle; and determining whether the vehicle has entered a curve based on the current position.

[0010] According to a second aspect of the present application, a vehicle speed planning device is provided. The device includes: a parameter acquisition module, configured to acquire initial state parameters of a vehicle entering a curve and the current turning angle of the vehicle on the curve; wherein the initial state parameters include an initial speed, a road surface friction coefficient, and a turning radius; a critical turning angle calculation module, configured to calculate a critical turning angle based on the initial state parameters; and a speed planning module, configured to calculate a target speed of the vehicle based on the initial state parameters and the current turning angle when the current turning angle has not reached the critical turning angle, and to calculate a maximum passing speed as the target speed of the vehicle based on the initial state parameters when the current turning angle reaches the critical turning angle.

[0011] According to a third aspect of the embodiments of this application, an electronic device is provided, comprising: a processor; and a memory storing computer-readable instructions, wherein when executed by the processor, the computer-readable instructions implement the vehicle speed planning method as described above.

[0012] According to a fourth aspect of the embodiments of this application, a computer-readable storage medium is provided, on which computer-readable instructions are stored, which, when executed by a processor, implement the vehicle speed planning method as described above.

[0013] According to a fifth aspect of the present application, a computer program product is provided, the computer program product including computer instructions stored in a computer-readable storage medium; the computer instructions are read and executed by a processor of a computer device to implement the vehicle speed planning method described above.

[0014] In the scheme of this application, firstly, the analytical solution in the angle domain avoids the problem of difficulty or large amount of computation in solving traditional time domain differential equations, and significantly reduces the computational complexity. Secondly, based on the critical turning angle, segmented speed planning is carried out. Acceleration planning is performed at the beginning of the vehicle entering the curve, and the maximum safe speed is maintained after the critical turning angle is reached. This not only ensures the safety of vehicle driving, but also realizes the fastest planning in the turning process, and improves traffic efficiency.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the embodiments of this application. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0017] Figure 1 This is a schematic flowchart illustrating a vehicle speed planning method according to an embodiment of this application; Figure 2 This is a schematic flowchart illustrating a vehicle speed planning method according to another embodiment of this application; Figure 3 This is a block diagram of a vehicle speed planning device according to an embodiment of this application; Figure 4 This is a hardware structure diagram of an electronic device according to an embodiment of this application.

[0018] The accompanying drawings have illustrated specific embodiments of the present application. More detailed descriptions will follow. These drawings and descriptions are not intended to limit the scope of the present application's embodiments in any way, but rather to illustrate the concepts of the present application's embodiments to those skilled in the art through specific embodiments. Detailed Implementation

[0019] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0020] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0021] Before providing a detailed explanation of the vehicle speed planning method provided in the embodiments of this application, the application scenarios provided in the embodiments of this application will be introduced first.

[0022] Currently, there is no unified theory for speed planning in path-based autonomous driving, especially regarding the highly nonlinear relationship between the friction coefficient and its allocation for acceleration or resistance to lateral forces during cornering. To maximize the utilization of wheel friction, the following speed-time related control equations exist: ; in, Indicates the coefficient of friction of the road surface. Represents gravitational acceleration. Indicates the turning radius.

[0023] Solving for the results At this point, it is difficult to obtain an analytical solution for the velocity as a function of time.

[0024] To address the aforementioned problems, this application provides a vehicle speed planning method. The core inventive concept of this method lies in transforming the traditional time-domain speed planning problem into an angle-domain problem. It transforms the state equation for speed and time, constrained by friction, into a state equation for angular velocity, based on the rotation angle of a fixed circle. For a fixed-radius circular arc, by introducing the rotation angle as an independent variable, the analytical relationship between speed and rotation angle is derived, thereby obtaining analytical solutions for angular velocity and the rotation angle of the fixed circle. This avoids the need for complex time-domain differential equation solving and achieves a balance between computational efficiency and planning accuracy. Figure 1 As shown, Figure 1 This application illustrates a vehicle speed planning method according to an embodiment of the present application. In a specific embodiment, this vehicle speed planning method can be applied to, for example... Figure 3The vehicle speed planning device 300 and the electronic equipment 400 equipped with the vehicle speed planning device 300 are shown. Figure 4 The specific process of this embodiment will be described below. Of course, it is understood that this method can be executed by an electronic device with computing power, such as a vehicle-mounted server, a cloud server, or other processors. The following will focus on... Figure 1 The process shown is explained in detail. The vehicle speed planning method may specifically include the following steps 110-140.

[0025] Step S110: Obtain the initial state parameters of the vehicle entering the curve and the current turning angle of the vehicle on the curve; wherein, the initial state parameters include the initial speed, the road surface friction coefficient and the turning radius.

[0026] For example, initial state parameters are fundamental parameters that determine the vehicle's cornering dynamics. Initial velocity indicates the longitudinal linear velocity of the vehicle when it first enters the curve, determining its initial kinetic energy state. The road friction coefficient indicates the adhesion between the vehicle's tires and the road surface, a key constraint limiting the vehicle's extreme motion; the larger the coefficient, the greater the lateral acceleration the vehicle can withstand, and the higher the permissible cornering speed. The turning radius determines the vehicle's steering geometry. The current turning angle indicates the central angle the vehicle has traveled on the curve, monotonically increasing with the driving process. In this embodiment, the current turning angle is used as the independent variable for speed planning, replacing the time variable in traditional methods.

[0027] Step S120: Calculate the critical rotation angle based on the initial state parameters.

[0028] For example, the critical turning angle is a key criterion for segmented speed planning in this application embodiment, determining the critical position where the vehicle transitions from a state where it can continue to accelerate to a state where it reaches the friction limit. When the vehicle first enters a curve, if the initial speed is low, the centrifugal force on the vehicle is small and has not reached the maximum adhesion limit of the road surface. At this time, the vehicle still has residual adhesion for tangential acceleration. As the vehicle travels at an angle in the curve, the speed gradually increases, and the centrifugal force increases accordingly. When it travels to a certain angle, the vehicle will reach the limit of the friction between the tires and the road surface. This specific angle is the critical turning angle.

[0029] Step S130: When the current turning angle has not reached the critical turning angle, calculate the target speed of the vehicle based on the initial state parameters and the current turning angle.

[0030] For example, when the current turning angle has not reached the critical turning angle, the vehicle is in the acceleration phase and has not yet reached the friction limit. In this phase, the target speed is determined based on the analytical function relationship between the initial state parameters and the current turning angle. This analytical function relationship reveals the law of speed change with the turning angle. Without the need for complex iterative integration calculations, the optimal target speed can be calculated in real time simply by substituting the current turning angle, which greatly reduces computational energy consumption.

[0031] Step S140: When the current turning angle reaches the critical turning angle, calculate the maximum passing speed based on the initial state parameters as the target speed of the vehicle.

[0032] For example, when the current turning angle reaches the critical turning angle, the vehicle has reached its friction limit and enters a constant speed phase. In this phase, the maximum passing speed is determined as the target speed based on the initial state parameters. The maximum passing speed indicates the limit speed at which the vehicle can safely pass through the curve under the constraints of the current road surface friction coefficient and turning radius. In this phase, all of the vehicle's adhesion is used to balance centrifugal force, and it can no longer provide tangential acceleration. Therefore, the vehicle should maintain this maximum passing speed at a constant speed to ensure traffic efficiency and prevent skidding.

[0033] Understandably, steps S130 and S140 above embody the core concept of transforming a time-domain problem into an angle-domain problem. Traditional methods typically establish dynamic equations with time as the independent variable. However, in turning scenarios, time-domain equations are often nonlinear differential equations, making it difficult to obtain analytical solutions, resulting in high computational complexity and poor real-time performance. This application's embodiment transforms the velocity planning problem into an angle-domain problem by introducing a turning angle variable, thereby enabling direct solution using analytical functions.

[0034] This application uses the critical turning angle as the dividing point to divide the cornering process into an acceleration stage utilizing adhesion and a constant speed stage maintaining limit equilibrium. By transforming the angle domain, the speed of the two stages can be solved quickly. This not only overcomes the shortcomings of complex calculation in traditional time domain programming, but also ensures that the vehicle passes through the curve at the fastest speed within the safety boundary, achieving a balance between safety and efficiency.

[0035] Furthermore, before step S110, the vehicle speed planning method provided in this application embodiment may further include: obtaining the current position of the vehicle; and determining whether the vehicle has entered a curve based on the current position.

[0036] Understandably, the vehicle's current position coordinates can be obtained in real time through the onboard positioning system and compared with the start and end point information of the curve stored in the high-precision map data. When the distance between the vehicle's current position coordinates and the start point of the curve is less than a preset threshold, it is determined that the vehicle has entered the curve, and the speed planning method is triggered. When the vehicle exits the end point of the curve, it is determined that the vehicle has left the curve, and the speed planning method stops executing. By detecting whether the vehicle has entered the curve in real time, a trigger condition is provided for the start and termination of speed planning, ensuring that the speed planning logic is activated only when the vehicle is in a curve scenario, avoiding unnecessary calculations on non-curved road sections, and reducing operating power consumption.

[0037] Optionally, the specific method for obtaining the initial state parameters in step S110 is not limited and can be set according to actual application requirements. For example, in an alternative example, the initial state parameters can be obtained through vehicle sensors.

[0038] The initial velocity, a key parameter in the initial state, can be obtained through various methods depending on the application requirements. One optional implementation is using wheel speed sensors integrated into the vehicle chassis. These sensors monitor the rotational speed of each wheel in real time, and the initial velocity can be derived through averaging or weighted processing. Another alternative implementation is using an onboard inertial measurement unit (IMU). The IMU measures the vehicle's three-axis acceleration, and the vehicle's velocity information is obtained by integrating the acceleration signals over time. Understandably, to improve data robustness, multi-sensor fusion is commonly used in practical applications. For example, a Kalman filter algorithm can be used to fuse data from wheel speed sensors and the IMU, ensuring accurate initial velocity values ​​are output even under conditions such as wheel slippage or uneven road surfaces.

[0039] The method for obtaining the road surface friction coefficient in the initial state parameters can be set according to actual application requirements. As an optional implementation, the empirical value of the friction coefficient for the current road segment can be directly read from high-precision map data; for example, 0.8 for dry asphalt pavement and 0.4 for wet pavement. Another optional implementation is to estimate it in real time through the vehicle's own perception system. For example, the wheel slip rate monitored by wheel speed sensors can be used to infer the current road surface friction coefficient from the tire model; or a visual sensor can be used to identify the road surface material (such as snow or water) and then look up the corresponding road surface friction coefficient in a table.

[0040] Optionally, the specific method for obtaining the current turning angle in step S110 is not limited and can be set according to actual application requirements. For example, in an alternative example, the current turning angle can be obtained through the vehicle's inertial navigation sensor. Another alternative example includes obtaining the turning distance between the vehicle's current position and its initial position upon entering the curve; and calculating the current turning angle based on the turning distance and the turning radius.

[0041] It should be noted that the vehicle's current position and initial position upon entering the curve can be obtained in real time through the onboard positioning system. When the vehicle enters the curve, the coordinates of the initial position are recorded, and then the straight-line distance or arc length along the path between the current position and the initial position is calculated in real time during the driving process.

[0042] After obtaining the distance through the above steps, the current turning angle can be calculated based on geometric relationships. According to the geometric properties of a circular arc, there is a definite mathematical relationship between the turning angle and the arc length or chord length. For example, if the obtained turning distance is the chord length *s* between the vehicle's current position and its initial position, then according to trigonometric relationships, the current turning angle... It can be calculated using a formula. Alternatively, based on the relationship between the central angle and the chord length, the current rotation angle can be calculated using the following formula 1: Formula 1; Where s represents the turning distance and r represents the turning radius. Using Formula 1, the vehicle's angle on the arc can be calculated in real time simply by obtaining the distance from the positioning data. This method of calculating the turning angle based on location is logically simple and computationally minimal, avoiding the cumulative errors that may arise from using complex algorithms.

[0043] Optionally, the specific method for calculating the critical turning angle in step S120 is not limited and can be set according to actual application requirements. For example, in an alternative example, the step of calculating the critical turning angle may include: calculating a first angle based on the initial speed, road surface friction coefficient, gravitational acceleration, and turning radius; wherein the first angle is used to indicate the angular offset corresponding to the initial speed; and calculating the critical turning angle based on a preset angle and the first angle.

[0044] For example, the method for calculating the first angle based on the initial velocity, road friction coefficient, gravitational acceleration, and turning radius may include: calculating the ratio of the square of the initial velocity to the product of the road friction coefficient, gravitational acceleration, and turning radius; calculating the arcsine of this ratio to obtain the first angle, which reflects the angular deviation of the initial velocity under frictional constraints. The preset angle can be π / 2. The method for calculating the critical turning angle based on the preset angle and the first angle may include: calculating the difference between the preset angle and the first angle; and taking half of this difference as the critical turning angle. Combining the above steps, the critical turning angle can be calculated according to the following formula 2: Formula 2; in, Indicates the critical turning angle. Indicates the initial velocity. Indicates the coefficient of friction of the road surface. Represents gravitational acceleration. Indicates the turning radius.

[0045] It should be noted that during a vehicle's cornering process, the adhesion provided by the tires must simultaneously meet the requirements for tangential acceleration and lateral steering; the vector sum of these two must not exceed the friction limit. This embodiment of the application derives the analytical solution by transforming the differential equation in the time domain into an integral equation in the angle domain through variable substitution.

[0046] Combination Figure 2 The specific method for calculating the target velocity in step S130 is not limited and can be set according to actual application requirements. For example, in an alternative example, the step of calculating the target velocity in step S130 may include: Step S131: Calculate the angle correction parameters based on the initial velocity, road surface friction coefficient, gravitational acceleration, and turning radius; Step S132: Calculate the velocity function value based on the current rotation angle and angle correction parameters; Step S133: Calculate the target speed based on the initial speed, road surface friction coefficient, turning radius, and speed function value.

[0047] For example, step S131, calculating the angle correction parameter, may include: calculating the ratio of the square of the initial velocity to a first product of the road friction coefficient, gravitational acceleration, and turning radius; and calculating the arcsine of this ratio as the angle correction parameter. Step S132, calculating the velocity function value, may include: calculating the sum of twice the current turning angle and the angle correction parameter; and calculating the sine of this sum as the velocity function value. Step S133, calculating the target velocity, may include: calculating a second product of the first product and the velocity function value; and taking the square root of the second product as the target velocity. Combining the above steps, the target velocity can be calculated according to the following formula 3: Formula 3; in, Indicates the target speed. Indicates the current turning angle. Indicates the initial velocity. Indicates the coefficient of friction of the road surface. Represents gravitational acceleration. Indicates the turning radius.

[0048] It should be noted that, unlike the numerical integration or iterative search methods used in existing technologies, the calculation formula provided in this application can directly calculate the optimal target speed based on the current turning angle, greatly reducing computational complexity. In the above formula... The term indicates the vehicle's maximum speed under the current road friction coefficient and turning radius; the phase term within the sine function. This integrates the vehicle's position information with its current turning angle and initial state, ensuring the accuracy of speed planning.

[0049] To more intuitively demonstrate the technical effects of this embodiment, the following explanation uses specific numerical values. Assume the initial speed of the vehicle entering the curve... Road surface friction coefficient Turning radius Gravitational acceleration is taken .

[0050] First, calculate the critical turning angle. According to Formula 2 above, first calculate the first angle. Then calculate the critical rotation angle. (Approximately 37.6 degrees), meaning that the vehicle is in the acceleration phase until it passes through a central angle of approximately 37.6 degrees.

[0051] During the acceleration phase, the target speed With the current corner It increases with the increase. For example, when a vehicle is driving to a corner. Substituting this into Formula 3 above, we can obtain the target velocity. When driving to the corner At that time, the target speed When driving to the corner The target speed reaches its maximum value at the critical turning angle. Afterward, the vehicle enters a constant speed phase, maintaining this maximum speed until it exits the curve. Using Formula 3 above, the optimal speed can be calculated simply by obtaining the vehicle's real-time turning angle, achieving a perfect balance between computational efficiency and planning accuracy.

[0052] Optionally, the specific method for calculating the maximum passing speed in step S140 is not limited and can be set according to actual application requirements. For example, in an alternative example, the step of calculating the maximum passing speed in step S140 may include: calculating a product based on the road surface friction coefficient, gravitational acceleration, and turning radius; wherein the product is used to indicate the vehicle's limit speed constraint value in the curve; and the maximum passing speed is calculated based on the product.

[0053] It should be noted that this step corresponds to the second stage of cornering, namely the constant speed phase. When the central angle of the vehicle reaches the critical turning angle, the vehicle's speed has increased to the limit under the current road conditions and geometric constraints. At this point, the friction between the tires and the road surface is fully used to balance the centrifugal force generated by the vehicle's turn. In this state, increasing speed can easily lead to vehicle skidding. Therefore, the vehicle should maintain this limit speed at a constant speed; this limit speed is the maximum passing speed. The lateral acceleration of the vehicle while cornering should not exceed the product of the coefficient of friction and the acceleration due to gravity, i.e. Thus, the maximum throughput speed can be derived. The embodiments of this application ensure that the vehicle's passage efficiency is maximized within the safety boundary by switching to constant speed control at critical turning angles.

[0054] It should be noted that the determination conditions for "current turning angle has not reached the critical turning angle" and "current turning angle has reached the critical turning angle" in steps S130 and S140 above can be in two ways: In the first way, the determination condition for "not reached" corresponds to the current turning angle being less than or equal to the critical turning angle, and the determination condition for "reached" corresponds to the current turning angle being greater than the critical turning angle; in the second way, the determination condition for "not reached" corresponds to the current turning angle being less than the critical turning angle, and the determination condition for "reached" corresponds to the current turning angle being greater than or equal to the critical turning angle. These two methods are physically equivalent; when the current turning angle is exactly equal to the critical turning angle, the target speed of the acceleration phase is... ,because =π / 2, sin(π / 2) = 1, therefore = The speed is consistent with the maximum speed of the constant speed segment. The equality condition of the current turning angle equal to the critical turning angle is categorized as either "not reached" or "reached." Speed ​​planning is continuous at the critical turning angle and will not produce jumps. Both methods can guarantee the correctness and continuity of the planning results.

[0055] Furthermore, to evaluate the efficiency of a vehicle navigating a curve, the method in this embodiment further includes calculating the total time for the vehicle to navigate the curve. The total time includes the acceleration phase time and the constant speed phase time. The acceleration phase time refers to the time required for the vehicle to travel from its initial position entering the curve to the critical turning angle position; the constant speed phase time refers to the time required for the vehicle to travel from the critical turning angle position to the end of the curve.

[0056] Regarding the acceleration phase time, since the vehicle's speed changes non-linearly with the steering angle, and there is no simple linear mapping between the steering angle and time, the acceleration phase time must be obtained through numerical integration. For example, the acceleration phase time can be calculated using the following formula. : Formula 4; Formula 5; Formula 6; Formula 7; For example, the time consumed during the constant speed phase The time taken during the constant speed phase can be calculated by dividing the remaining arc length of the curve by the speed, and can be obtained using the following formula 8: Formula 8; in, It indicates the arc angle through which the vehicle has turned.

[0057] Ultimately, the total time it takes for the vehicle to navigate the curve. Through the above-described solution, this application provides a complete method for evaluating cornering time, which can not only plan the optimal speed in real time but also accurately predict travel time, providing data support for autonomous driving systems.

[0058] Furthermore, in real-world autonomous driving environments, vehicles frequently encounter curves with continuously changing curvature, such as transition curves or complex curves combining arcs of different radii. In these scenarios, the turning radius is no longer a constant value but a variable that varies with the arc length of the path. Therefore, the method in this embodiment may further include: in response to the vehicle's driving path being a variable radius path, discretizing the variable radius path into multiple segments of fixed radius curves, and executing the vehicle speed planning method described in the foregoing embodiments for each segment of fixed radius curve. Through discretization, the continuously changing complex curvature curve is approximately fitted to several segments of fixed radius arcs that connect end to end. It should be understood that the granularity of discretization determines the accuracy of the fitting; the more drastic the curvature change of the path, the more discrete segments are usually required; conversely, in regions with gentle curvature changes, longer arc segments can be used to reduce computational load.

[0059] For example, the discretization process can be performed based on the geometric parameters of the path. For instance, the curvature at each path point can be calculated from a high-precision map. For consecutive path points with similar curvature, a fixed-radius arc can be fitted, with the radius taken as the average or weighted average of the curvatures of that path point segment. In this way, a continuous variable-radius path is decomposed into a sequence of fixed-radius arcs with defined geometric parameters (radius, arc length, central angle).

[0060] After discretization, the aforementioned speed planning method is applied to each fixed-radius circular arc. For example, for the Nth circular arc, the speed at its starting point is used as the initial speed of that arc, the fitted radius of that arc is used as the turning radius, and the critical turning angle and target speed of that arc are calculated in conjunction with the current road friction coefficient. When the vehicle completes the Nth circular arc and enters the (N+1)th circular arc, the speed at the end of the Nth circular arc becomes the initial speed of the (N+1)th circular arc, thus ensuring the continuity of speed planning.

[0061] Through the above-described solution, the velocity planning method applicable only to ideal scenarios with a fixed radius is extended to a wider range of real-world scenarios with variable radii. This not only demonstrates the strong versatility and robustness of the proposed solution but also provides a method for efficient passage of autonomous vehicles in complex road conditions. Compared to the complex numerical integration solutions for variable radius paths in existing technologies, the discretization method in this application maintains the advantages of low computational cost and fast response speed while ensuring planning accuracy.

[0062] The above embodiments describe in detail the vehicle speed planning method provided by the embodiments of this application. In other embodiments, this application also provides a vehicle speed planning device. Figure 3 This is a block diagram of a vehicle speed planning device according to an embodiment of this application, such as... Figure 3 As shown, the vehicle speed planning device 300 includes: a parameter acquisition module 310, a critical turning angle calculation module 320, and a speed planning module 330.

[0063] The parameter acquisition module 310 is used to acquire the initial state parameters of the vehicle entering the curve and the current turning angle of the vehicle on the curve; wherein, the initial state parameters include the initial speed, the road surface friction coefficient and the turning radius; The critical rotation angle calculation module 320 is used to calculate the critical rotation angle based on the initial state parameters; The speed planning module 330 is used to calculate the target speed of the vehicle based on the initial state parameters and the current turning angle when the current turning angle has not reached the critical turning angle, and to calculate the maximum passing speed as the target speed of the vehicle based on the initial state parameters when the current turning angle reaches the critical turning angle.

[0064] In other embodiments, this solution also provides an electronic device, such as... Figure 4 As shown, the electronic device 400 also includes a processor 410 and one or more memories 420. The one or more memories 420 are used to store program instructions executed by the processor 410. When the processor 410 executes the program instructions, it implements the vehicle speed planning method described above.

[0065] Furthermore, processor 410 may include one or more processing cores. Processor 410 runs or executes instructions, programs, code sets, or instruction sets stored in memory 420, and calls data stored in memory 420. Optionally, processor 4410 may be implemented using at least one hardware form of Digital Signal Processing (DSP), Field-Programmable Gate Array (FPGA), or Programmable Logic Array (PLA). Processor 410 may integrate one or a combination of several of the following: Central Processing Unit (CPU), Graphics Processing Unit (GPU), and modem. The CPU primarily handles the operating system, user interface, and applications; the GPU is responsible for rendering and drawing the displayed content; and the modem handles wireless communication. It is understood that the modem may also not be integrated into the processor and may be implemented using a separate communication chip.

[0066] In other embodiments, this solution also provides a computer-readable storage medium, which may be included in the cloud server described in the above embodiments; or it may exist independently and not assembled into the cloud server. The aforementioned computer-readable storage medium carries computer-readable instructions, which, when executed by a processor, implement the methods in any of the above embodiments.

[0067] It should be noted that the computer-readable medium shown in the embodiments of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination of the two. Computer-readable storage media can be, for example, but not limited to: electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), flash memory, optical fiber, portable compact disc read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such transmitted data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. The computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination thereof.

[0068] In an exemplary embodiment, this application also provides a computer program product, which, when executed by a processor, is used to implement the above-described vehicle speed planning method.

[0069] The units described in the embodiments of this application can be implemented in software or hardware, and the described units can also be located in a processor. The names of these units do not necessarily limit the specific unit itself.

[0070] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the embodiments disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein.

[0071] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A vehicle speed planning method, characterized in that, include: The initial state parameters of the vehicle entering the curve and the current turning angle of the vehicle on the curve are obtained; wherein, the initial state parameters include initial speed, road surface friction coefficient and turning radius; Calculate the critical rotation angle based on the initial state parameters; When the current turning angle has not reached the critical turning angle, the target speed of the vehicle is calculated based on the initial state parameters and the current turning angle; When the current turning angle reaches the critical turning angle, the maximum passing speed is calculated based on the initial state parameters and used as the target speed of the vehicle.

2. The method according to claim 1, characterized in that, The step of calculating the target speed of the vehicle based on the initial state parameters and the current turning angle includes: The angle correction parameters are calculated based on the initial velocity, the road surface friction coefficient, the gravitational acceleration, and the turning radius. Calculate the velocity function value based on the current rotation angle and the angle correction parameter; The target speed is calculated based on the initial speed, the road surface friction coefficient, the turning radius, and the speed function value.

3. The method according to claim 1, characterized in that, The step of calculating the critical rotation angle based on the initial state parameters includes: A first angle is calculated based on the initial velocity, the road surface friction coefficient, gravitational acceleration, and the turning radius; wherein, the first angle is used to indicate the angular offset corresponding to the initial velocity; The critical turning angle is calculated based on the preset angle and the first angle.

4. The method according to claim 1, characterized in that, The calculation of the maximum passing speed based on the initial state parameters includes: The product is calculated based on the road surface friction coefficient, gravitational acceleration, and turning radius; wherein the product is used to indicate the vehicle's maximum speed constraint value in the curve; The maximum passing speed is calculated based on the product.

5. The method according to claim 1, characterized in that, The step of obtaining the current turning angle of the vehicle on the curve includes: Obtain the turning distance between the vehicle's current position and its initial position when entering the curve; Calculate the current turning angle based on the turning distance and the turning radius.

6. The method according to any one of claims 1-5, characterized in that, The method further includes: Obtain the current location of the vehicle; Determine whether the vehicle has entered a curve based on its current position.

7. A vehicle speed planning device, characterized in that, The device includes: The parameter acquisition module is used to acquire the initial state parameters of the vehicle entering the curve and the current turning angle of the vehicle on the curve; wherein, the initial state parameters include the initial speed, the road surface friction coefficient and the turning radius; The critical rotation angle calculation module is used to calculate the critical rotation angle based on the initial state parameters. The speed planning module is used to calculate the target speed of the vehicle based on the initial state parameters and the current turning angle when the current turning angle has not reached the critical turning angle, and to calculate the maximum passing speed as the target speed of the vehicle based on the initial state parameters when the current turning angle reaches the critical turning angle.

8. An electronic device, characterized in that, The electronic device includes: processor; A memory storing computer-readable instructions that, when executed by the processor, implement the method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium contains program code that can be invoked by a processor to execute the method as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, The computer program product includes computer instructions, which are stored in a computer-readable storage medium. The computer instructions are read and executed by the processor of the computer device to implement the method as described in any one of claims 1 to 6.

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