A vehicle terminal, a vehicle turning control method and device

Abstract

The application discloses a vehicle terminal, a vehicle turning control method and a device, and relates to the technical field of vehicle control. The vehicle turning control method comprises the following steps: acquiring a current position of a vehicle and a desired trajectory of the vehicle; finding a nearest point of the current position in the desired trajectory, and finding at least two preview points on the desired trajectory starting from the nearest point; determining a current turning radius of the vehicle according to the nearest point and the at least two preview points; when the current turning radius is smaller than a minimum turning radius of the vehicle, finding a first steering preview point on the desired trajectory; wherein the distance between the first steering preview point and the current position on the desired trajectory is a first distance; the distance between the first preview point found on the desired trajectory and the current position on the desired trajectory is a second distance; since the first distance is greater than the second distance, the first tire deflection angle of the vehicle determined according to the first steering preview point can realize early steering, and through early steering, the purpose of controlling a lateral error is achieved.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, specifically to a vehicle terminal, a vehicle turning control method, and a device. Background Technology

[0002] Autonomous driving technology, based on environmental perception technology, tracks a target trajectory obtained through decision-making and planning by controlling both the longitudinal and lateral directions. Lateral control refers to control perpendicular to the vehicle's direction of motion. Due to physical constraints, actual vehicles cannot directly move perpendicular to their direction of motion. Instead, lateral movement is indirectly achieved by adjusting the steering wheel angle to control the vehicle's forward direction. The performance of lateral movement varies among different vehicles due to differences in structure, steering wheel angle limits, and steering angular velocity. To standardize the evaluation and comparison of lateral movement performance, a series of indicators exist, with minimum turning radius being a commonly used one.

[0003] For urban vehicles, the roads they travel on are typically standardized, structured roads, rarely encountering curvatures exceeding the capabilities of the actual vehicles. This means the turning radius on actual roads is usually greater than the minimum turning radius achievable by the vehicle. However, in commercial vehicle usage scenarios, the roads they travel on are often unstructured, and due to the larger dimensions of commercial vehicles, the turning radius on some feasible roads may be smaller than the minimum turning radius achievable by the actual vehicle. For example, in the actual operation of smart ports, due to the compact internal space, the turning radius of some roads is only 6-7 meters, while the total length of transport trucks is approximately 20 meters, and their minimum achievable turning radius is 10 meters, making it difficult to accurately track a given road trajectory. In such cases, trucks can be allowed to partially use the adjacent lanes, but the lateral error must still be controlled to minimize interference with other vehicles. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a vehicle terminal, a vehicle turning control method and device to control lateral errors during unmanned vehicle driving.

[0005] According to a first aspect, embodiments of the present invention provide a vehicle turning control method, comprising the following steps: obtaining the current position of the vehicle and the desired trajectory of the vehicle; finding the nearest point of the current position in the desired trajectory, and using the nearest point as a starting point, searching forward for at least two aiming points on the desired trajectory; determining the current turning radius of the vehicle based on the nearest point and the at least two aiming points; when the current turning radius is less than the minimum turning radius of the vehicle, searching forward for a first steering aiming point on the desired trajectory; wherein the distance from the first steering aiming point to the current position on the desired trajectory is a first distance; the distance from the first aiming point found forward on the desired trajectory to the current position on the desired trajectory is a second distance, and the first distance is greater than the second distance; determining a first tire deflection angle of the vehicle based on the first steering aiming point.

[0006] The vehicle turning control method provided in this invention obtains the vehicle's current position and desired trajectory, and then finds the nearest point of the current position on the desired trajectory. Starting from the nearest point, it searches for at least two pre-aiming points forward on the desired trajectory. The current turning radius of the vehicle is determined based on the nearest point and the at least two pre-aiming points. When the current turning radius is less than the vehicle's minimum turning radius, it can be considered that the vehicle cannot keep up with the desired trajectory, so it needs to turn in advance. Furthermore, a first steering aiming point is found on the desired trajectory, where the distance from the first steering aiming point to the current position on the desired trajectory is the first distance. The distance from the first pre-aiming point found forward on the desired trajectory to the current position on the desired trajectory is the second distance. Since the first distance is greater than the second distance, the first tire deflection angle of the vehicle determined based on the first steering aiming point can achieve early steering. By turning in advance, the purpose of controlling lateral error is achieved.

[0007] Specifically, the vehicle turning control method further includes the following steps: when the current turning radius is greater than or equal to the minimum turning radius, the current driving speed of the vehicle is obtained; a pre-aiming distance is determined based on the current driving speed, and the pre-aiming distance is searched forward on the desired trajectory with the nearest point as the starting point to obtain a second steering aiming point; the second tire deflection angle of the vehicle is determined based on the second steering aiming point.

[0008] Specifically, the step of finding at least two pre-aiming points forward on the expected trajectory, starting from the nearest point, includes: finding the first pre-aiming point by moving forward a first distance on the expected trajectory, starting from the nearest point; and finding the second pre-aiming point by moving forward a first distance on the expected trajectory, starting from the first pre-aiming point.

[0009] Specifically, determining the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points includes: fitting the nearest point, the first pre-aiming point, and the second pre-aiming point to obtain the radius of the fitted circle; and using the radius of the fitted circle as the current turning radius of the vehicle.

[0010] Specifically, when the current turning radius is less than the minimum turning radius, searching for the first turning aiming point forward on the desired trajectory includes: when the current turning radius is less than the minimum turning radius, using the second pre-aiming point as the first turning aiming point.

[0011] Specifically, determining the first tire deflection angle of the vehicle based on the first steering aiming point includes: obtaining the first ideal heading angle of the vehicle based on the nearest point and the first steering aiming point; acquiring the current attitude of the vehicle, and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the first ideal heading angle and the actual heading angle to obtain a first heading angle deviation; determining whether the first heading angle deviation is within a preset first range; when the first heading angle deviation is not within the first range, using the first heading angle deviation as the first tire deflection angle; or, determining the second tire deflection angle of the vehicle based on the second steering aiming point includes: obtaining the second ideal heading angle of the vehicle based on the nearest point and the second steering aiming point; acquiring the current attitude of the vehicle, and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the second ideal heading angle and the actual heading angle to obtain a second heading angle deviation; determining whether the second heading angle deviation is within a preset second range; when the second heading angle deviation is not within the second range, using the second heading angle deviation as the second tire deflection angle.

[0012] Specifically, after determining whether the first heading angle deviation is within a preset first range, the method further includes: when the first heading angle deviation is within the first range, obtaining the front axle center position of the vehicle; obtaining a first lateral compensation angle based on the front axle center position, the first steering aiming point, and the first ideal heading angle; calculating a first tire deflection angle of the vehicle using a preset first formula based on the first heading angle deviation and the first lateral compensation angle; or, after determining whether the second heading angle deviation is within a preset second range, the method further includes: when the second heading angle deviation is within the second range, obtaining the front axle center position of the vehicle; obtaining a second lateral compensation angle based on the front axle center position, the second steering aiming point, and the second ideal heading angle; calculating a second tire deflection angle of the vehicle using a preset second formula based on the second heading angle deviation and the second lateral compensation angle.

[0013] Specifically, after determining the first tire deflection angle of the vehicle based on the first steering aiming point, the method further includes: determining whether the first tire deflection angle is within a preset third range; when the first tire deflection angle is within the third range, using the first tire deflection angle as the actual tire deflection angle of the vehicle; when the first tire deflection angle is less than the minimum value of the third range, using the minimum value of the third range as the actual tire deflection angle of the vehicle; when the first tire deflection angle is greater than the maximum value of the third range, using the maximum value of the third range as the actual tire deflection angle of the vehicle; or, after determining the second tire deflection angle of the vehicle based on the second steering aiming point, the method further includes: determining whether the second tire deflection angle is within a preset fourth range; when the second tire deflection angle is within the fourth range, using the second tire deflection angle as the actual tire deflection angle of the vehicle; when the second tire deflection angle is less than the minimum value of the fourth range, using the minimum value of the fourth range as the actual tire deflection angle of the vehicle; when the second tire deflection angle is greater than the maximum value of the fourth range, using the maximum value of the fourth range as the actual tire deflection angle of the vehicle.

[0014] According to a second aspect, embodiments of the present invention also provide a vehicle turning control device, including an acquisition module, a search module, a current turning radius determination module, a steering aiming point determination module, and a tire deflection angle determination module. The acquisition module is used to acquire the current position of the vehicle and the vehicle's desired trajectory. The search module is used to find the nearest point of the current position in the desired trajectory, and using the nearest point as a starting point, search forward at least two pre-aiming points on the desired trajectory. The current turning radius determination module is used to determine the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points. The steering aiming point determination module is used to search forward on the desired trajectory for a first steering aiming point when the current turning radius is less than the vehicle's minimum turning radius. The distance from the first steering aiming point to the current position on the desired trajectory is a first distance; the distance from the first pre-aiming point found forward on the desired trajectory to the current position on the desired trajectory is a second distance, and the first distance is greater than the second distance. The tire deflection angle determination module is used to determine the tire deflection angle of the vehicle based on the first steering aiming point.

[0015] According to a third aspect, embodiments of the present invention provide a vehicle terminal, including a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the computer instructions to perform the vehicle turning control method described in the first aspect or any embodiment of the first aspect. Attached Figure Description

[0016] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0017] Figure 1 This is a diagram illustrating a late turn.

[0018] Figure 2 This is a diagram illustrating premature turning.

[0019] Figure 3 This is a flowchart illustrating the vehicle turning control method in Embodiment 1 of the present invention;

[0020] Figure 4 For when R <R min Schematic diagram of the first heading angle deviation and the first lateral compensation angle;

[0021] Figure 5 When R≥R min Schematic diagram of the second heading angle deviation and the second lateral compensation angle;

[0022] Figure 6 This is a flowchart illustrating an example of a vehicle turning control method in Embodiment 1 of the present invention;

[0023] Figure 7 This is a flowchart illustrating an example of the tire deflection angle calculation method in Embodiment 1 of the present invention.

[0024] Figure 8 A schematic diagram illustrating the effect achievable using the vehicle control method of Embodiment 1 of the present invention;

[0025] Figure 9 A schematic diagram illustrating an example of the effects that can be achieved by using the vehicle control method of Embodiment 1 of the present invention;

[0026] Figure 10 A schematic diagram illustrating another example of the effects achievable using the vehicle control method of Embodiment 1 of the present invention;

[0027] Figure 11 This is a schematic diagram of the vehicle turning control device in Embodiment 2 of the present invention;

[0028] Figure 12 This is a schematic diagram of the vehicle terminal in Embodiment 3 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0031] Example 1

[0032] When the vehicle is traveling from left to right Figure 1 This is a diagram illustrating turning too late. Figure 2 This is a diagram illustrating premature turning. Figure 1 and Figure 2 It can be seen that turning too late excessively occupies the left lane, while turning too early excessively occupies the right lane. In other words, turning too late or too early will occupy too much road space, so it is necessary to control the lateral error during autonomous driving.

[0033] Embodiment 1 of the present invention provides a vehicle turning control method. Figure 3 This is a flowchart illustrating the vehicle turning control method in Embodiment 1 of the present invention, as shown below. Figure 3 As shown, the vehicle turning control method of Embodiment 1 of the present invention includes the following steps:

[0034] S101: Obtain the current position of the vehicle and the desired trajectory of the vehicle.

[0035] Specifically, the vehicle's current position can be obtained through the environmental perception module in the vehicle, which can be the vehicle's horizontal and vertical coordinates.

[0036] The vehicle's desired trajectory can be pre-stored in the vehicle's controller.

[0037] S102: Find the nearest point of the current position in the desired trajectory, and starting from the nearest point, search forward for at least two pre-aiming points on the desired trajectory.

[0038] Finding the nearest point to the current position in the desired trajectory can be done using any of the existing technologies, which will not be elaborated here.

[0039] Specifically, the following scheme can be adopted to find at least two pre-aiming points forward on the expected trajectory, starting from the nearest point: starting from the nearest point, find a first distance forward on the expected trajectory to obtain the first pre-aiming point; starting from the first pre-aiming point, find the first distance forward on the expected trajectory to obtain the second pre-aiming point.

[0040] The first distance is a fixed value related to the vehicle model. Specifically, the first distance is determined by the vehicle's minimum turning radius, which is typically half of the vehicle's minimum turning radius.

[0041] S103: Determine the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points.

[0042] Specifically, the method for determining the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points can be as follows: fit the nearest point, the first pre-aiming point, and the second pre-aiming point to obtain the radius of the fitted circle; and use the radius of the fitted circle as the current turning radius.

[0043] S104: When the current turning radius is less than the minimum turning radius of the vehicle, a first steering aiming point is found on the desired trajectory; wherein the distance from the first steering aiming point to the current position on the desired trajectory is a first distance; the distance from the first pre-aiming point found forward on the desired trajectory to the current position on the desired trajectory is a second distance, and the first distance is greater than the second distance.

[0044] Specifically, when searching for two pre-aiming points forward on the desired trajectory, namely the first pre-aiming point and the second pre-aiming point, the second pre-aiming point is used as the first turning aiming point.

[0045] This is because when the current turning radius is less than the vehicle's minimum turning radius, it can be considered that the vehicle cannot keep up with the expected trajectory, and therefore it needs to turn in advance. Currently, the first aiming point is generally used as the first steering aiming point. However, in Embodiment 1 of this invention, the first steering aiming point is not the first aiming point, but is farther than the first aiming point, that is, the first distance is greater than the second distance, thereby enabling early steering.

[0046] S105: Determine the first tire deflection angle of the vehicle based on the first steering aiming point.

[0047] Specifically, determining the first tire deflection angle of the vehicle based on the first steering aiming point includes: obtaining the first ideal heading angle of the vehicle based on the nearest point and the first steering aiming point; acquiring the current attitude of the vehicle, and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the first ideal heading angle and the actual heading angle to obtain a first heading angle deviation; determining whether the first heading angle deviation is within a preset first range; and when the first heading angle deviation is not within the first range, using the first heading angle deviation as the first tire deflection angle.

[0048] Furthermore, after determining whether the first heading angle deviation is within a preset first range, the method further includes: when the first heading angle deviation is within the first range, obtaining the front axle center position of the vehicle; obtaining a first lateral compensation angle based on the front axle center position, the first steering aiming point, and the first ideal heading angle; and calculating the first tire deflection angle of the vehicle using a preset first formula based on the first heading angle deviation and the first lateral compensation angle.

[0049] Specifically, the vehicle's current attitude can be obtained through the environmental perception module within the vehicle.

[0050] In other words, when the first heading angle deviation is within a given first range, for example (δ) min ,δ max Within ) time, it can be calculated according to the first formula: To calculate the first tire deflection angle γ1, where δ1 represents the first heading angle deviation, This represents the first lateral compensation angle. k1 and k2 are given parameters that are adjusted based on actual operational results. When the first heading angle deviation is outside the given first range (δ...), the compensation angle is applied. min ,δ max Within a certain range, the first tire deflection angle does not need to be calculated; it can be directly equal to the first heading angle deviation. In other words, priority is given to meeting the heading angle tracking requirements, and when the steering capability is sufficient to accommodate changes in heading angle, the influence of lateral error is also considered. This allows for good tracking performance when tracking curves with different turning radii.

[0051] For example, such as Figure 4 As shown, when R <R min At this point, P3 is the first steering aiming point. The angle between the straight line determined by the nearest point P0 and the first steering aiming point P3 and the horizontal direction is the first ideal heading angle α1; the vehicle attitude angle, i.e., the angle between the vehicle body and the horizontal direction, is the actual heading angle θ; and the angle between the straight line determined by the front axle center position L0 and the first steering aiming point P3 and the horizontal direction is β. Therefore, the first heading angle deviation δ1 = α1 – θ, and the first lateral compensation angle can be defined.

[0052] Furthermore, after determining the first tire deflection angle of the vehicle based on the first steering aiming point, the method further includes: determining whether the first tire deflection angle is within a preset third range; when the first tire deflection angle is within the third range, using the first tire deflection angle as the actual tire deflection angle of the vehicle; when the first tire deflection angle is less than the minimum value of the third range, using the minimum value of the third range as the actual tire deflection angle of the vehicle; when the first tire deflection angle is greater than the maximum value of the third range, using the maximum value of the third range as the actual tire deflection angle of the vehicle. The third range can be determined based on the vehicle's performance.

[0053] In other words, obtaining the first tire deflection angle also includes a step of correcting the first tire deflection angle, which ensures that the corrected first tire deflection angle is within the vehicle's capability range, thus guaranteeing that the vehicle can complete the steering.

[0054] Therefore, the vehicle turning control method provided in Embodiment 1 of the present invention obtains the vehicle's current position and the vehicle's desired trajectory, and then finds the nearest point of the current position in the desired trajectory. Starting from the nearest point, it searches forward at least two aiming points on the desired trajectory, and determines the vehicle's current turning radius based on the nearest point and the at least two aiming points. When the current turning radius is less than the vehicle's minimum turning radius, it can be considered that the vehicle cannot keep up with the desired trajectory, so it needs to turn in advance. Furthermore, it finds a first steering aiming point on the desired trajectory, where the distance from the first steering aiming point to the current position on the desired trajectory is the first distance; the distance from the first aiming point found forward on the desired trajectory to the current position on the desired trajectory is the second distance. Since the first distance is greater than the second distance, the first tire deflection angle of the vehicle determined based on the first steering aiming point can achieve early turning, thereby achieving the purpose of lateral error control.

[0055] As another technical solution, after step S103, the following steps S106 to S107 are also included.

[0056] S106: When the current turning radius is greater than or equal to the minimum turning radius, obtain the current driving speed of the vehicle.

[0057] Specifically, the vehicle's current speed can be obtained through the vehicle speed detection module.

[0058] S107: Determine the aiming distance based on the current driving speed, and starting from the nearest point, search forward along the desired trajectory to find the aiming distance and obtain the second steering aiming point.

[0059] It should be noted that the distance from the second turning aiming point to the current position on the desired trajectory is the third distance, which is less than the first distance and the second distance.

[0060] This is because when the current turning radius is greater than or equal to the vehicle's minimum turning radius, it can be assumed that the vehicle can keep up with the desired trajectory, and therefore there is no need to turn in advance. Therefore, normal steering is sufficient. Specifically, the aiming distance is determined based on the current driving speed, and starting from the nearest point, the aiming distance is searched forward along the desired trajectory to obtain the second steering aiming point, thereby enabling normal steering.

[0061] S108: Determine the second tire deflection angle of the vehicle based on the second steering aiming point.

[0062] Specifically, determining the second tire deflection angle of the vehicle based on the second steering aiming point includes: obtaining the second ideal heading angle of the vehicle based on the nearest point and the second steering aiming point; acquiring the current attitude of the vehicle and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the second ideal heading angle and the actual heading angle to obtain the second heading angle deviation; determining whether the second heading angle deviation is within a preset second range; and when the second heading angle deviation is not within the second range, using the second heading angle deviation as the second tire deflection angle.

[0063] Furthermore, after determining whether the second heading angle deviation is within a preset second range, the method further includes: when the second heading angle deviation is within the second range, obtaining the front axle center position of the vehicle; obtaining a second lateral compensation angle based on the front axle center position, the second steering aiming point, and the second ideal heading angle; and calculating the second tire deflection angle of the vehicle using a preset second formula based on the second heading angle deviation and the second lateral compensation angle.

[0064] Specifically, the vehicle's current attitude can be obtained through the environmental perception module within the vehicle.

[0065] Specifically, the second range can be the same as the first range.

[0066] In other words, when the second heading angle deviation is within a given second range, for example (δ) min ,δ max When the first tire deflection angle γ2 is within the given range (δ,φ), it can be calculated using the second formula: γ2=f(δ,φ)=k3*δ2+k4*φ2, where δ2 represents the second heading angle deviation, φ2 represents the second lateral compensation angle, and k3 and k4 are given parameters that are adjusted based on actual operating results. When the second heading angle deviation is outside the given first range (δ... min ,δmax When the first tire is within the first yaw angle, the second tire deflection angle does not need to be calculated; it can be directly equal to the deviation of the first yaw angle. In other words, priority is given to meeting the requirements of yaw angle tracking, and when the steering capability is sufficient to meet the changes in yaw angle, the influence of lateral error is also taken into account. This allows for good tracking performance when tracking curves with different turning radii.

[0067] For example, such as Figure 5 As shown, when R≥R min P1 is the second steering aiming point. The angle between the straight line determined by the nearest point P0 and the second steering aiming point P1 and the horizontal direction is the second ideal heading angle α2; the vehicle attitude angle, that is, the angle between the vehicle body and the horizontal direction, is the actual heading angle θ; and the angle between the straight line determined by the front axle center position L0 of the vehicle and the second steering aiming point P1 and the horizontal direction is β. Then, the second heading angle deviation δ2 = α2 – θ and the second lateral compensation angle φ2 = β – α2 can be defined.

[0068] Furthermore, after determining the second tire deflection angle of the vehicle based on the second steering aiming point, the method further includes: determining whether the second tire deflection angle is within a preset fourth range; when the second tire deflection angle is within the fourth range, using the second tire deflection angle as the actual tire deflection angle of the vehicle; when the second tire deflection angle is less than the minimum value of the fourth range, using the minimum value of the fourth range as the actual tire deflection angle of the vehicle; when the second tire deflection angle is greater than the maximum value of the fourth range, using the maximum value of the fourth range as the actual tire deflection angle of the vehicle. The fourth range can be determined based on the vehicle's performance and can be the same as the third range.

[0069] In other words, obtaining the second tire deflection angle also includes a step of correcting the second tire deflection angle, which ensures that the corrected second tire deflection angle is within the vehicle's capability range, thus guaranteeing that the vehicle can complete the steering.

[0070] Therefore, the vehicle turning control method provided in Embodiment 1 of the present invention obtains the current position and the desired trajectory of the vehicle, and then finds the nearest point of the current position in the desired trajectory. Starting from the nearest point, it searches forward at least two aiming points on the desired trajectory. The current turning radius of the vehicle is determined based on the nearest point and the at least two aiming points. When the current turning radius is greater than or equal to the minimum turning radius of the vehicle, it can be considered that the vehicle can keep up with the desired trajectory, so there is no need to turn in advance. Furthermore, by finding a second steering aiming point on the desired trajectory, since the second steering aiming point is determined based on the current driving speed, normal turning can be achieved.

[0071] To illustrate the vehicle turning control method of Embodiment 1 of the present invention in more detail, a specific example is given, such as... Figure 2 , Figure 3 , Figure 6 and Figure 7 As shown, this example includes the following steps:

[0072] Step 1: Describe the vehicle's desired trajectory in the form of data points and store it in the lateral control module. The vehicle's desired trajectory includes the desired position coordinates, trajectory tangent direction angle, and desired vehicle speed. The desired position coordinates include, but are not limited to, coordinates located in the global coordinate system.

[0073] Step 2: The vehicle's current information is obtained in real time through the environmental perception module and the vehicle speed detection module, mainly including the vehicle's lateral and longitudinal coordinates, driving direction and speed, and the vehicle's attitude angle. The current position information is then sent to the lateral control module.

[0074] Step 3: Based on the current positioning point (e.g., the vehicle's horizontal and vertical coordinates), find the nearest point P0 on the desired trajectory, and find the first pre-aiming point P2 on the trajectory, such that the distance from the nearest point P0 to the first pre-aiming point P2 on the trajectory is L;

[0075] Step 4: Starting from the first aiming point P2, find the second aiming point P3 forward on the trajectory, such that the distance between the first aiming point and the second aiming point P3 on the trajectory is L;

[0076] Step 5: Calculate the radius R of the fitted circle of the three points: the nearest point P0, the first preview point P2, and the second preview point P3;

[0077] Step 6: Combine the radius R with the vehicle's minimum turning radius R min Compare, if R ≥ R min Proceed to step 7; otherwise, proceed to step 8.

[0078] Step 7: Calculate the aiming distance S based on the current driving speed v, and starting from the nearest point P0, find the conventional aiming point P1 (i.e., the first steering aiming point) on the trajectory, such that the distance from the nearest point P0 to the conventional aiming point P1 on the trajectory is S. Proceed to Step 9. It should be noted that P1 here is not necessarily less than P2, but it is definitely less than P3. This is because this algorithm mainly considers the control of the steering process without vehicle slippage, and the vehicle speed should be relatively low, at least ensuring S < 2 * L, meaning P1 is definitely less than P3.

[0079] Step 8: Set the second aiming point P3 (i.e. the second turning aiming point) as the normal aiming point, and jump to step 9 for calculation;

[0080] Step 9: Calculate the heading angle deviation δ and the lateral compensation angle φ based on the value of the conventional pre-aiming point (i.e., the first steering aiming point or the second steering aiming point) and the front axle center position L0 of the vehicle, and determine whether the heading angle deviation value is within the given threshold (δ). min ,δ max Within the range, if δ < δ min Then let the tire deflection angle γ = δ; if δ > δ max Let the tire deflection angle γ = δ; if it is within a given threshold range, let γ = f(δ, φ).

[0081] Step 10: Calculate whether the tire deflection angle γ is within the given tire deflection angle threshold (γ). min ,γ max Within the range, that is, when γ > γ max Let the tire deflection angle γ = γ max And when γ < γ min Let the tire deflection angle γ = γ min .

[0082] By using the method of Embodiment 1 of the present invention for control, the following can be achieved: Figure 8 , Figure 9 and Figure 10 The effect shown, in which Figure 8 This is a schematic diagram illustrating the effect achievable using the vehicle control method of Embodiment 1 of the present invention. Figure 9 A schematic diagram illustrating an example of the effects that can be achieved by using the vehicle control method of Embodiment 1 of the present invention; Figure 10 This is a schematic diagram illustrating another example of the effects achievable using the vehicle control method of Embodiment 1 of the present invention. For example... Figure 9 As shown, the minimum curve radius in the desired trajectory is approximately 8 meters, while Figure 10 The minimum curvature of the desired trajectory is approximately 6.7 meters. The control algorithm proposed in this invention can effectively achieve the expected goal, namely, it avoids excessive bias to one side during tracking, ensuring a uniform distribution of lateral errors on both sides, thereby minimizing the maximum absolute value of the lateral error when tracking the desired trajectory. In other words, the control algorithm proposed in this invention has strong adaptability.

[0083] It should be noted that existing lateral control technologies mainly include PID control, linear control, and nonlinear control. Among them, linear control, such as Linear Quadratic Regulator (LQR), and nonlinear control, such as Model Predictive Control (MPC) and adaptive control, can achieve optimal adjustment of lateral errors during steering.

[0084] MPC control achieves optimal control of lateral error through model-based prediction, rolling optimization, and a feedforward-feedback control structure. It requires significant real-time computation to solve the optimization problem. In contrast, LQR control has relatively less real-time computation, but it is difficult to add external structural constraints. Furthermore, both MPC and LQR require high accuracy in their mathematical models, involve numerous parameters, and are highly sensitive to parameter changes, necessitating considerable time for parameter tuning and optimization.

[0085] In addition, for commercial vehicles such as container trucks, the working environment is relatively harsh, and some motion parameters fluctuate greatly, which can cause the MPC and LQR algorithms to fail in actual implementation. Therefore, a more robust control method is needed to achieve optimal control of lateral error.

[0086] The vehicle turning control method provided in Embodiment 1 of the present invention has the following advantages compared with the lateral control technology in the prior art:

[0087] 1. By predicting the turning radius on the track, it is possible to turn in advance, thereby making the absolute value of the lateral deviation relatively small during the tracking process;

[0088] 2. The point where a turn needs to be made in advance can be predicted through simple calculations, requiring less real-time computation.

[0089] 3. The minimum turning radius is introduced into the control method, which makes the control method calculation based on geometric constraints. Moreover, only the minimum turning radius of the vehicle needs to be provided as a parameter, without the need to build a complex mathematical model, making it widely applicable.

[0090] 4. Since the control method only uses the minimum turning radius as a structural parameter, this parameter is basically fixed after the vehicle is manufactured, so there will be no failure problem.

[0091] Example 2

[0092] Corresponding to Embodiment 1 of the present invention, Embodiment 2 of the present invention provides a vehicle turning control device, such as... Figure 11 As shown, the vehicle turning control device of Embodiment 2 of the present invention includes an acquisition module 20, a search module 21, a current turning radius determination module 22, a steering aiming point determination module 23, and a tire deflection angle determination module 24.

[0093] Specifically, the acquisition module 20 is used to acquire the current position of the vehicle and the desired trajectory of the vehicle;

[0094] The search module 21 is used to find the nearest point of the current position in the expected trajectory, and to search forward at least two pre-aiming points on the expected trajectory starting from the nearest point;

[0095] The current turning radius determination module 22 is used to determine the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points;

[0096] The steering aiming point determination module 23 is used to find a first steering aiming point forward on the expected trajectory when the current turning radius is less than the minimum turning radius of the vehicle; wherein the distance from the first steering aiming point to the current position on the expected trajectory is a first distance; the distance from the first aiming point found forward on the expected trajectory to the current position on the expected trajectory is a second distance, and the first distance is greater than the second distance;

[0097] The tire deflection angle determination module 24 is used to determine the first tire deflection angle of the vehicle based on the first steering aiming point.

[0098] Furthermore, when the current turning radius is greater than or equal to the minimum turning radius, the acquisition module 20 is also used to acquire the current driving speed of the vehicle; the steering aiming point determination module 23 is used to determine the pre-aiming distance based on the current driving speed, and starting from the nearest point, to search forward along the desired trajectory to find the pre-aiming distance and obtain the second steering aiming point; the tire deflection angle determination module 24 is used to determine the second tire deflection angle of the vehicle based on the second steering aiming point.

[0099] The search module 21 is specifically used to: starting from the nearest point, search forward along the desired trajectory by the first distance to obtain the first pre-aiming point; starting from the first pre-aiming point, search forward along the desired trajectory by the first distance to obtain the second pre-aiming point.

[0100] The current turning radius determination module 22 is specifically used to: fit the nearest point, the first pre-aiming point and the second pre-aiming point to obtain the radius of the fitted circle; and use the radius of the fitted circle as the current turning radius.

[0101] The steering aiming point determination module 23 is specifically used to: use the second pre-aiming point as the first steering aiming point.

[0102] The tire deflection angle determination module 24 is specifically used for: obtaining the first ideal heading angle of the vehicle based on the nearest point and the first steering aiming point; obtaining the current attitude of the vehicle and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the first ideal heading angle and the actual heading angle to obtain a first heading angle deviation; determining whether the first heading angle deviation is within a preset first range; when the first heading angle deviation is not within the first range, using the first heading angle deviation as the first tire deflection angle; or, obtaining the second ideal heading angle of the vehicle based on the nearest point and the second steering aiming point; obtaining the current attitude of the vehicle and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the second ideal heading angle and the actual heading angle to obtain a second heading angle deviation; determining whether the second heading angle deviation is within a preset second range; when the second heading angle deviation is not within the second range, using the second heading angle deviation as the second tire deflection angle.

[0103] The tire deflection angle determination module 24 is further configured to: when the first heading angle deviation is within the first range, obtain the front axle center position of the vehicle; obtain a first lateral compensation angle based on the front axle center position, the first steering aiming point, and the first ideal heading angle; calculate the first tire deflection angle of the vehicle using a preset first formula based on the first heading angle deviation and the first lateral compensation angle; or, when the second heading angle deviation is within the second range, obtain the front axle center position of the vehicle; obtain a second lateral compensation angle based on the front axle center position, the second steering aiming point, and the second ideal heading angle; calculate the second tire deflection angle of the vehicle using a preset second formula based on the second heading angle deviation and the second lateral compensation angle.

[0104] Furthermore, the tire deflection angle determination module 24 is also used to: determine whether the first tire deflection angle is within a preset third range; when the first tire deflection angle is within the third range, use the first tire deflection angle as the actual tire deflection angle of the vehicle; when the first tire deflection angle is less than the minimum value of the third range, use the minimum value of the third range as the actual tire deflection angle of the vehicle; when the first tire deflection angle is greater than the maximum value of the third range, use the maximum value of the third range as the actual tire deflection angle of the vehicle; or, determine whether the second tire deflection angle is within a preset fourth range; when the second tire deflection angle is within the fourth range, use the second tire deflection angle as the actual tire deflection angle of the vehicle; when the second tire deflection angle is less than the minimum value of the fourth range, use the minimum value of the fourth range as the actual tire deflection angle of the vehicle; when the second tire deflection angle is greater than the maximum value of the fourth range, use the maximum value of the fourth range as the actual tire deflection angle of the vehicle.

[0105] For specific details regarding the aforementioned vehicle turning control device, please refer to the relevant documentation. Figures 1 to 10 The relevant descriptions and effects in the illustrated embodiments are for understanding purposes only and will not be repeated here.

[0106] Example 3

[0107] This invention also provides a vehicle terminal, such as... Figure 12 As shown, the vehicle terminal may include a processor 31 and a memory 32, wherein the processor 31 and the memory 32 may be connected by a bus or other means.

[0108] Furthermore, this embodiment of the invention also provides a vehicle, which includes the aforementioned vehicle terminal. Specifically, the vehicle includes, but is not limited to, engineering vehicles and passenger vehicles; more specifically, engineering vehicles may be forklifts, cranes, road rollers, etc.

[0109] Processor 31 can be a central processing unit (CPU). Processor 31 can also be 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, or combinations of the above types of chips.

[0110] Memory 32, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the vehicle turning control method in this embodiment of the invention (e.g., Figure 11 The module shown includes the acquisition module 20, the search module 21, the current turning radius determination module 22, the steering aiming point determination module 23, and the tire deflection angle determination module 24. The processor 31 executes various functional applications and data processing by running non-transitory software programs, instructions, and modules stored in the memory 32, thereby implementing the vehicle turning control method in the above method embodiment.

[0111] The memory 32 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 31, etc. Furthermore, the memory 32 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 32 may optionally include memory remotely located relative to the processor 31, and these remote memories may be connected to the processor 31 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0112] The one or more modules are stored in the memory 32, and when executed by the processor 31, they perform actions such as... Figures 1-10 The vehicle turning control method in the illustrated embodiment.

[0113] For specific details regarding the aforementioned vehicle terminals, please refer to the relevant documentation. Figures 1 to 11 The relevant descriptions and effects in the illustrated embodiments are for understanding purposes only and will not be repeated here.

[0114] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium can also include combinations of the above types of memory.

[0115] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A vehicle turning control method, characterized in that, include: Obtain the vehicle's current location and the vehicle's desired trajectory; Find the nearest point to the current position in the desired trajectory, and starting from the nearest point, search forward at least two pre-aiming points on the desired trajectory; The current turning radius of the vehicle is determined based on the nearest point and the at least two pre-aiming points; When the current turning radius is less than the vehicle's minimum turning radius, the vehicle searches for a first steering aiming point forward on the desired trajectory. The distance from the first turning aiming point to the current position on the expected trajectory is the first distance; the distance from the first pre-aiming point found forward on the expected trajectory to the current position on the expected trajectory is the second distance, and the first distance is greater than the second distance; When the current turning radius is greater than or equal to the minimum turning radius, the current driving speed of the vehicle is obtained, the pre-aiming distance is determined based on the current driving speed, and the pre-aiming distance is searched forward on the desired trajectory with the nearest point as the starting point to obtain the second steering aiming point; The first tire deflection angle of the vehicle is determined based on the first steering aiming point, and the second tire deflection angle of the vehicle is determined based on the second steering aiming point; The step of determining the first tire deflection angle of the vehicle based on the first steering aiming point includes: obtaining the first ideal heading angle of the vehicle based on the nearest point and the first steering aiming point; obtaining the current attitude of the vehicle and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the first ideal heading angle and the actual heading angle to obtain a first heading angle deviation; determining whether the first heading angle deviation is within a preset first range; when the first heading angle deviation is not within the first range, using the first heading angle deviation as the first tire deflection angle; or; The step of determining the second tire deflection angle of the vehicle based on the second steering aiming point includes: obtaining the second ideal heading angle of the vehicle based on the nearest point and the second steering aiming point; obtaining the current attitude of the vehicle and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the second ideal heading angle and the actual heading angle to obtain the second heading angle deviation; determining whether the second heading angle deviation is within a preset second range; and when the second heading angle deviation is not within the second range, using the second heading angle deviation as the second tire deflection angle.

2. The method according to claim 1, characterized in that, The step of searching for at least two pre-aiming points forward along the desired trajectory, starting from the nearest point, includes: Starting from the nearest point, the first distance is traveled forward along the desired trajectory to obtain the first pre-aiming point; Starting from the first aiming point, move forward along the desired trajectory by the first distance to obtain the second aiming point.

3. The method according to claim 2, characterized in that, Determining the vehicle's current turning radius based on the nearest point and the at least two pre-aiming points includes: The radius of the fitted circle is obtained by fitting the nearest point, the first pre-aiming point, and the second pre-aiming point. The radius of the fitted circle is used as the current turning radius of the vehicle.

4. The method according to claim 2, characterized in that, When the current turning radius is less than the minimum turning radius, searching for the first turning aiming point forward on the desired trajectory includes: When the current turning radius is less than the minimum turning radius, the second pre-aiming point is used as the first steering aiming point.

5. The method according to claim 1, characterized in that, After determining whether the first heading angle deviation is within a preset first range, the process further includes: When the first heading angle deviation is within the first range, the front axle center position of the vehicle is obtained; The first lateral compensation angle is obtained based on the front axle center position, the first steering aiming point, and the first ideal heading angle; The first tire deflection angle of the vehicle is calculated using a preset first formula based on the first heading angle deviation and the first lateral compensation angle. Alternatively, after determining whether the second heading angle deviation is within a preset second range, the method further includes: When the second heading angle deviation is within the second range, the front axle center position of the vehicle is obtained; The second lateral compensation angle is obtained based on the front axle center position, the second steering aiming point, and the second ideal heading angle; The second tire deflection angle of the vehicle is calculated using a preset second formula based on the second heading angle deviation and the second lateral compensation angle.

6. The method according to claim 1, characterized in that, After determining the first tire deflection angle of the vehicle based on the first steering aiming point, the method further includes: Determine whether the first tire deflection angle is within a preset third range; When the first tire deflection angle is within the third range, the first tire deflection angle is taken as the actual tire deflection angle of the vehicle; When the first tire deflection angle is less than the minimum value of the third range, the minimum value of the third range is taken as the actual tire deflection angle of the vehicle. When the first tire deflection angle is greater than the maximum value of the third range, the maximum value of the third range shall be taken as the actual tire deflection angle of the vehicle. Alternatively, after determining the second tire deflection angle of the vehicle based on the second steering aiming point, the method further includes: Determine whether the second tire deflection angle is within the preset fourth range; When the second tire deflection angle is within the fourth range, the second tire deflection angle is taken as the actual tire deflection angle of the vehicle; When the second tire deflection angle is less than the minimum value of the fourth range, the minimum value of the fourth range shall be taken as the actual tire deflection angle of the vehicle. When the second tire deflection angle is greater than the maximum value of the fourth range, the maximum value of the fourth range is taken as the actual tire deflection angle of the vehicle.

7. A vehicle turning control device, characterized in that, include: The acquisition module is used to acquire the vehicle's current location and the vehicle's desired trajectory; The search module is used to find the nearest point of the current position in the expected trajectory, and starting from the nearest point, search forward for at least two pre-aiming points on the expected trajectory; The current turning radius determination module is used to determine the current turning radius of the vehicle based on the nearest point and the at least two pre-aiming points; The steering aiming point determination module is used to find a first steering aiming point forward on the desired trajectory when the current turning radius is less than the minimum turning radius of the vehicle. The distance from the first steering aiming point to the current position on the expected trajectory is the first distance; the distance from the first pre-aiming point found forward on the expected trajectory to the current position on the expected trajectory is the second distance, and the first distance is greater than the second distance; it is also used to obtain the current driving speed of the vehicle when the current turning radius is greater than or equal to the minimum turning radius; Based on the current driving speed, the aiming distance is determined, and starting from the nearest point, the aiming distance is searched forward along the desired trajectory to obtain the second steering aiming point; A tire deflection angle determination module is used to determine the tire deflection angle of the vehicle based on the first steering aiming point, and to determine the second tire deflection angle of the vehicle based on the second steering aiming point; The step of determining the first tire deflection angle of the vehicle based on the first steering aiming point includes: obtaining the first ideal heading angle of the vehicle based on the nearest point and the first steering aiming point; obtaining the current attitude of the vehicle, and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the first ideal heading angle and the actual heading angle to obtain a first heading angle deviation; determining whether the first heading angle deviation is within a preset first range; when the first heading angle deviation is not within the first range, using the first heading angle deviation as the first tire deflection angle; or, the step of determining the second tire deflection angle of the vehicle based on the second steering aiming point includes: obtaining the second ideal heading angle of the vehicle based on the nearest point and the second steering aiming point; obtaining the current attitude of the vehicle, and obtaining the actual heading angle of the vehicle based on the current attitude; calculating the difference between the second ideal heading angle and the actual heading angle to obtain a second heading angle deviation; determining whether the second heading angle deviation is within a preset second range; when the second heading angle deviation is not within the second range, using the second heading angle deviation as the second tire deflection angle.

8. A vehicle terminal, characterized in that, include: A memory and a processor are interconnected, the memory stores computer instructions, and the processor executes the vehicle turning control method according to any one of claims 1 to 6 by executing the computer instructions.

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