Vehicle control method and system, equipment, medium and product

Abstract

The invention relates to a vehicle control method and system, equipment, a medium and a product. The vehicle control method comprises the steps that an expected path is determined, and current operation parameters of a vehicle are obtained; determining a preview position of the vehicle according to the current operation parameters and the expected path, and determining a first expected yaw velocity and a second expected yaw velocity of the vehicle at the preview position; determining a yaw moment of the vehicle based on the first expected yaw velocity or the second expected yaw velocity; and driving the vehicle to run according to the yawing moment. By adopting the method, the yawing moment of the vehicle can be predicted and adjusted in advance by utilizing the real-time state of the vehicle and the condition of the road ahead in the running process of the vehicle, the dynamic response of the vehicle to emergencies such as turning or obstacle avoidance is optimized, the rollover risk of the vehicle is reduced, and the stability and safety of the vehicle are enhanced.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a vehicle control method and system, equipment, medium, and product. Background Art

[0002] In modern vehicle dynamic control systems, controlling yaw torque is a key technology to ensure vehicle stability and handling performance. However, most existing yaw torque control methods rely on real-time operating parameters fed back by the vehicle, and adjust the yaw torque according to the real-time operating parameters. Controlling the vehicle based on the existing yaw torque control method results in the vehicle's yaw torque being adjusted according to the vehicle's real-time operating parameters only after an emergency occurs. For example, after detecting that the vehicle is at risk of rollover, the yaw torque is adjusted according to the vehicle's current operating parameters, and the vehicle is driven to run with the adjusted yaw torque for emergency avoidance. Such a control method has response lag and insufficient handling of emergencies, and cannot ensure the safety and stability of vehicle operation. Especially in complex road environments, the yaw torque control effect of the prior art is greatly limited. Summary of the invention

[0003] Based on this, a vehicle control method, system, device, medium, and product are provided to solve the problem that the risk of rollover cannot be avoided in advance in the prior art.

[0004] In a first aspect, a vehicle control method is provided, the method comprising:

[0005] Determining a desired path and obtaining current operating parameters of the vehicle;

[0006] Determining a preview position of the vehicle according to the current operating parameters and the expected path, and determining a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position; the first expected yaw rate is determined by a longitudinal speed and a wheelbase of the vehicle, and the second expected yaw rate is determined by current operating parameters of the vehicle and / or physical parameters of the vehicle;

[0007] determining a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate;

[0008] The vehicle is driven to travel according to the yaw moment.

[0009] Optionally, the current operating parameters include the current position of the vehicle;

[0010] Then, determining the preview position of the vehicle and determining a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position according to the current operating parameters and the expected path includes:

[0011] Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position;

[0012] Determining a preview steering angle of the front wheel of the vehicle at the preview position based on a preset correspondence relationship among the steering angle, the preview distance and the road curvature; the preset correspondence relationship includes multiple sets of values ​​of the steering angle, the preview distance and the road curvature;

[0013] determining a proportionality factor based on a ratio of a longitudinal speed of the vehicle and a wheelbase of the vehicle;

[0014] determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle;

[0015] The second expected yaw rate is determined based on current operating parameters of the vehicle and / or physical parameters of the vehicle.

[0016] Optionally, determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle includes:

[0017] The first expected yaw rate is determined according to a product of a tangent value of the preview steering angle and the proportionality coefficient.

[0018] Optionally, determining the yaw moment of the vehicle based on the first expected yaw angular velocity or the second expected yaw angular velocity includes:

[0019] In response to the first expected yaw rate or the second expected yaw rate reaching a preset condition, the yaw moment of the vehicle is determined based on the first expected yaw rate or the second expected yaw rate; the preset condition indicates that the vehicle is in an unstable state, and the preset condition includes: the first expected yaw rate or the second expected yaw rate is outside a preset range.

[0020] Optionally, determining the yaw moment of the vehicle based on the first expected yaw angular velocity or the second expected yaw angular velocity includes:

[0021] Obtaining the moment of inertia of the vehicle around a preset coordinate system;

[0022] Determine a yaw rate change rate; wherein the yaw rate change rate indicates a rate of change of a difference between the first expected yaw rate or the second expected yaw rate and a preset threshold value per unit time;

[0023] A yaw moment of the vehicle is determined based on the yaw rate change rate and the rotational inertia.

[0024] In a second aspect, a control system of a vehicle is provided, the control system comprising:

[0025] A first determination module, used to determine a desired path and obtain current operating parameters of the vehicle;

[0026] a second determination module, configured to determine a preview position of the vehicle and a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position according to the current operating parameters and the expected path; the first expected yaw rate is determined by a longitudinal speed and a wheelbase of the vehicle, and the second expected yaw rate is determined by a current operating parameter of the vehicle and / or a physical parameter of the vehicle;

[0027] a third determining module, configured to determine a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate;

[0028] A driving module is used to drive the vehicle to travel according to the yaw moment.

[0029] Optionally, the current operating parameter includes a current position of the vehicle; then the second determining module is further used for:

[0030] Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position;

[0031] Determining a preview steering angle of the front wheels of the vehicle at the preview position based on a preset correspondence between a steering angle, a preview distance, and a road curvature;

[0032] determining a proportionality factor based on a ratio of a longitudinal speed of the vehicle and a wheelbase of the vehicle;

[0033] determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle;

[0034] The second expected yaw rate is determined based on current operating parameters of the vehicle and / or physical parameters of the vehicle.

[0035] According to a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, wherein the processor implements the control method according to the first aspect when executing the computer program.

[0036] According to a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the computer program is executed by a processor, the control method according to the first aspect is implemented.

[0037] According to a fifth aspect, a computer program product is provided, comprising a computer program, wherein when the computer program is executed by a processor, the control method according to the first aspect is implemented.

[0038] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present application.

[0039] The control method, system, equipment, medium and product of the above-mentioned vehicle determine the preview position of the vehicle, determine the yaw moment of the vehicle according to the two expected yaw angular velocities of the vehicle at the preview position, and during the operation of the vehicle, use the real-time status of the vehicle and the road conditions ahead to predict and adjust the yaw moment of the vehicle in advance, optimize the dynamic response of the vehicle in the face of emergencies such as turning or obstacle avoidance, reduce the risk of vehicle rollover, and enhance the stability and safety of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 A first flow chart of a method for controlling a vehicle in one embodiment;

[0041] Figure 2 is a first schematic diagram of vehicle driving parameters of a vehicle control method in one embodiment;

[0042] Figure 3 A second schematic diagram of vehicle driving parameters of a vehicle control method in one embodiment;

[0043] Figure 4 A second flow chart of a method for controlling a vehicle in one embodiment;

[0044] Figure 5 is a schematic structural diagram of a control system of a vehicle in one embodiment;

[0045] Figure 6 FIG. 1 is a schematic diagram of the structure of an electronic device in an embodiment. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] It should be noted that the diagram provided in the present embodiment only illustrates the basic concept of the present application in a schematic manner, so the diagram only shows the components related to the present application rather than drawing according to the number, shape and size of the components during actual implementation. The type, quantity and ratio of each component during actual implementation can be a random change, and its component layout type may also be more complicated. The structure, ratio, size, etc. illustrated by the accompanying diagram of this specification are only used to match the content disclosed in the specification, so that people familiar with this technology can understand and read, and are not used to limit the restrictive conditions that can be implemented in this application, so they have no technical substantive significance. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect that can be produced by this application and the purpose that can be achieved, should still fall within the scope that the technical content disclosed in this application can cover. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are also only for the convenience of narration, rather than for limiting the scope that can be implemented in this application. The change or adjustment of its relative relationship, without substantial change of technical content, should also be regarded as the scope that can be implemented in this application.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the text does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] As shown in this document, unless the context clearly indicates an exception, the words "a", "an", "an" and / or "the" do not refer to the singular and may also include the plural, unless the context clearly indicates an exception. Generally speaking, the terms "include" and "comprise" only indicate that the steps and elements that have been clearly identified are included, and these steps and elements do not constitute an exclusive list. The method or device may also include other steps or elements.

[0050] The definitions of inclusion in this document, such as the terms "having", "may have", "include" or "may include" used herein, indicate the existence of the corresponding functions, operations, elements, etc. herein, and do not limit the existence of one or more other functions, operations, elements, etc. In addition, it should be understood that the terms "including" or "having" used herein indicate the existence of the features, numbers, steps, operations, elements, components, or a combination thereof described in the specification, without excluding the existence or addition of one or more other features, numbers, steps, operations, elements, components, or a combination thereof.

[0051] In the embodiments of the present application, prefixes such as "first" and "second" are used only to distinguish different description objects, and have no limiting effect on the position, order, priority, quantity or content of the described objects. The use of prefixes such as ordinal numbers to distinguish description objects in the embodiments of the present application does not constitute a limitation on the described objects. For the statement of the described objects, please refer to the description in the context of the claims or embodiments, and no unnecessary limitation should be constituted due to the use of such prefixes. In addition, in the description of the present embodiment, unless otherwise specified, the meaning of "multiple" is two or more.

[0052] Figure 1 A vehicle control method is provided as an exemplary embodiment of the present application, and the control method includes:

[0053] S11. Determine the expected path and obtain the current operating parameters of the vehicle.

[0054] Among them, the current operating parameters of the vehicle are various parameters used to monitor and describe the performance, current state and behavior of the vehicle in real time during the operation of the vehicle. The current operating parameters of the vehicle include but are not limited to: the current position of the vehicle, longitudinal speed, lateral speed, longitudinal acceleration, lateral acceleration, front wheel turning angle, tire angular acceleration, tire sideslip angle, tire slip rate, etc.

[0055] The expected path is an ideal driving route calculated by the path planning algorithm based on the vehicle's current position, current operating parameters and road conditions. Road conditions include but are not limited to: road conditions, road markings, road surface friction coefficient, road curvature, road type, road slope, etc. Road conditions can be identified by the camera of the vehicle's intelligent driving system. For example, when the camera identifies the road conditions of the current road, the path planning algorithm can be used to calculate that the path along the center line of the road is the expected path.

[0056] S12. Determine a preview position of the vehicle according to current operating parameters and an expected path, and determine a first expected yaw angular velocity and a second expected yaw angular velocity of the vehicle at the preview position.

[0057] The preview position is the position of the vehicle after it has traveled a preset time and / or a preset distance along the expected path. For example, the preview position is the position of the vehicle after it has traveled 10 meters along the expected path.

[0058] After the desired path is determined, the preview position of the vehicle is determined based on the current operating parameters of the vehicle and the desired path. For example, after the path along the center line of the road is determined to be the desired path, the position 10 meters away from the current position on the center line of the road is determined as the preview position based on the current position of the vehicle, and the steering angle of the vehicle is controlled so that the vehicle moves forward in line with the center line of the road.

[0059] The yaw rate of a vehicle is the rate at which the vehicle rotates around the vertical axis of the vehicle body. It characterizes the rotation speed of the vehicle body relative to its direction of movement when the vehicle turns or changes lanes, and reflects the lateral stability of the vehicle when turning or changing lanes.

[0060] The first expected yaw rate of the vehicle is calculated based on the expected yaw rate formula, which assumes that the vehicle is a rigid body, takes into account the longitudinal and lateral motion of the vehicle, and uses the front wheel steering angle of the vehicle as the control input. The second expected yaw rate is calculated based on the seven-degree-of-freedom model, which takes into account the longitudinal, lateral, vertical motion of the vehicle, and rotational motion around three axes, while taking into account the steering of the front and rear wheels, and their mutual influence.

[0061] When the vehicle is not interfered by external force, the calculated first expected yaw rate and the second expected yaw rate are the same.

[0062] If the calculated first expected yaw rate and the second expected yaw angle are both within the preset range, it is determined that the vehicle is in a stable state at the preview position. If the calculated first expected yaw rate or the second expected yaw rate is outside the preset range, it is determined that the vehicle may have an unstable trend at the preview position. At this time, intervention can be made at the current position of the vehicle to control the yaw moment of the vehicle, thereby controlling the braking torque of the vehicle to make the vehicle reach a stable state, avoid the vehicle from being unstable at the preview position, and reduce the risk of rollover of the vehicle. At this time, the vehicle is affected by external forces, and the yaw rate cannot be calculated by the first expected yaw rate calculation formula that only changes the steering angle. At this time, a more complex seven-degree-of-freedom model is used to calculate the yaw rate of the vehicle at the preview position, so the first expected yaw rate and the second expected yaw rate calculated after external force intervention are different. It is possible to determine whether the vehicle is in a stable state by judging whether the first expected yaw rate and the second expected yaw rate are both within the preset range, and adjust the yaw moment of the vehicle in advance when the vehicle shows an unstable trend, thereby providing a more stable and comfortable driving experience.

[0063] In one embodiment, the current operating parameters include a current position of the vehicle, and determining a preview position of the vehicle according to the current operating parameters and the expected path, and determining a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position, comprises:

[0064] Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position;

[0065] Based on the corresponding relationship among the steering angle, the preview distance and the road curvature, determining the preview steering angle of the front wheel of the vehicle at the preview position; the preset corresponding relationship includes multiple sets of values ​​of the steering angle, the preview distance and the road curvature;

[0066] Determining a proportionality coefficient based on a ratio of a longitudinal speed of the vehicle to a wheelbase of the vehicle; the longitudinal speed and the wheelbase may be obtained by analyzing an image captured by a camera of the vehicle; or by vehicle operating parameters acquired by a vehicle control unit;

[0067] Determining a first expected yaw rate according to the proportionality coefficient and the preview steering angle;

[0068] Based on current operating parameters of the vehicle and / or physical parameters of the vehicle, a second expected yaw rate is determined.

[0069] The steering angle of the front wheels of the vehicle is the rotation angle of the front wheels of the vehicle relative to the longitudinal axis of the vehicle. The first expected yaw rate is calculated by the preview steering angle and the proportional coefficient to obtain the instantaneous yaw rotation rate of the vehicle under the current driving speed, vehicle wheelbase and preview steering angle.

[0070] The calculation method of the first expected yaw angular velocity and the second expected yaw angular velocity is further explained below in conjunction with specific formulas.

[0071] After determining the actual preview distance and the expected path, the road curvature of the expected path at the preview position can be obtained. The road curvature represents the degree of curvature of the road at the preview position. The road curvature can be calculated by the formula It is obtained that K1 is the road curvature, R is the radius of curvature, or the road curvature can be obtained by collecting the vehicle's position (longitude, latitude) and direction (heading angle) data through on-board sensors and analyzing the above data.

[0072] The preview model equation can be expressed as the corresponding relationship between the steering angle, preview distance and road curvature. After determining the actual preview distance, the preview steering angle can be obtained through the preview model equation. The preview model equation is as follows:

[0073]

[0074] Among them, Figure 2 As shown, δ is the preview steering angle, k1, k2, k3 are gain coefficients, e is the lateral deviation between the current position of the vehicle and the desired path, and the lateral deviation indicates the perpendicular distance between the center of mass position of the vehicle at the preview position and the tangent line of the desired path at the current position; K is the heading deviation between the vehicle’s current position and the tangent direction of the preview path. The heading deviation indicates the angle difference between the tangent of the desired path at the current position and the tangent of the desired path at the preview position. lis the road curvature at the preview position, L p It is the vertical distance between the current position and the preview position.

[0075] The proportionality coefficient is the ratio of the longitudinal speed of the vehicle to the wheelbase of the vehicle. After the preview steering angle is determined, the first expected yaw rate can be determined according to the product of the tangent value of the preview steering angle and the proportionality coefficient. Considering that the vehicle moves forward at a constant speed, there is no acceleration or deceleration change, and only the steering angle changes, the first expected yaw rate can be calculated using the expected yaw rate formula:

[0076]

[0077] Among them, δ is the preview steering angle of the vehicle, V is the longitudinal speed of the vehicle, L is the wheelbase of the vehicle, is the proportionality coefficient, is the first expected yaw rate.

[0078] In order to accurately determine the state of the vehicle under more complex input conditions and judge the stability of the vehicle, the longitudinal, lateral and yaw degrees of freedom of the vehicle can be simultaneously considered, and then combined with the rotation of the four tires, a seven-degree-of-freedom dynamic model can be established. The second expected yaw angular velocity of the vehicle can be calculated by substituting the current operating parameters of the vehicle and the physical parameters of the vehicle into the seven-degree-of-freedom dynamic model, wherein the current operating parameters of the vehicle are various parameters used to monitor and describe the performance, current state and behavior of the vehicle in real time during the operation of the vehicle, and the current operating parameters of the vehicle include but are not limited to: the current position of the vehicle, longitudinal speed, lateral speed, longitudinal acceleration, lateral acceleration, front wheel angle, angular acceleration of the tire, tire side slip angle, tire slip rate, etc., and the physical parameters of the vehicle include but are not limited to the vehicle mass, the distance from the front axle of the vehicle to the center of mass, the distance from the rear axle of the vehicle to the center of mass, the radius of the tire of the vehicle, the wheelbase of the vehicle, the distance from the center of mass of the vehicle to the ground, etc. The second expected yaw rate is calculated as follows: based on the current operating parameters of the vehicle, a seven-degree-of-freedom vehicle model corresponding to the current operating parameters is established, the seven-degree-of-freedom vehicle model includes vertical load equations for each tire, side slip angle equations for each tire, and slip rate equations for each tire, the vertical load equations for each tire, the side slip angle equations for each tire, and the slip rate equations for each tire are substituted into the magic formula to obtain tire lateral force expressions and tire longitudinal force expressions corresponding to the current operating parameters, the tire lateral force expressions and tire longitudinal force expressions are substituted into the balance equations in the seven-degree-of-freedom model to obtain the second expected yaw rate of the vehicle.

[0079] like Figure 3 As shown, a seven-degree-of-freedom model is established based on the current operating parameters of the vehicle, where X represents the longitudinal direction of the coordinate axis and Y represents the transverse direction of the coordinate axis. The seven-degree-of-freedom model includes:

[0080] 1. Longitudinal force balance equation:

[0081]

[0082] 2. Lateral force balance equation:

[0083]

[0084] 3. Moment balance equation around the Z axis:

[0085]

[0086] 4. The torque balance equation of four wheels:

[0087]

[0088] 5. Vertical load equation for each tire:

[0089]

[0090]

[0091] 6. Equation of tire slip angle for each wheel:

[0092]

[0093] 7. Longitudinal acceleration of each wheel in the wheel coordinate system:

[0094]

[0095] 8.Equation of slip rate of each wheel:

[0096]

[0097] Among them, Figure 3 As shown, m is the vehicle mass, V x is the longitudinal velocity of the vehicle, V y is the lateral velocity of the vehicle, is the longitudinal acceleration of the vehicle, is the lateral acceleration of the vehicle, δ is the front wheel preview steering angle of the vehicle, t w1 is the front axle track of the vehicle, t w2 is the rear axle track of the vehicle, a is the distance from the front axle to the center of mass of the vehicle, b is the distance from the rear axle to the center of mass of the vehicle, l is the wheelbase of the vehicle, I z is the moment of inertia of the vehicle around the Z axis, I tw is the moment of inertia of the tire, is the angular acceleration of the tire, R is the tire radius, h g is the distance from the center of mass to the ground, γ is the second expected yaw rate, is the yaw angular acceleration. Fijk is the tire force (when i = x represents longitudinal direction, i = y represents transverse direction, i = z represents vertical direction; j = f represents front wheel, j = r represents rear wheel; k = l represents left wheel, k = r represents right wheel; for example, F xfl represents the longitudinal force of the left front wheel), α jk is the tire slip angle (when j = f represents the front wheel, j = r represents the rear wheel; k = l represents the left wheel, k = r represents the right wheel; for example, α fl represents the sideslip angle of the left front wheel), V tjk represents the longitudinal speed of the tire in the wheel coordinate system (j=f represents the front wheel, j=r represents the rear wheel; k=l represents the left wheel, k=r represents the right wheel; for example, V tfl represents the longitudinal speed of the left front wheel), λ jk is the tire slip rate of the vehicle (j=f represents the front wheel, j=r represents the rear wheel; k=l represents the left wheel, k=r represents the right wheel; for example, λ fl represents the tire slip rate of the left front wheel), w jk is the tire angular velocity (j=f for the front wheel, j=r for the rear wheel; k=l for the left wheel, k=r for the right wheel; for example, w fl represents the tire angular velocity of the left front wheel).

[0098] Substituting the current operating parameters of the above vehicle into the seven-degree-of-freedom model, we can obtain four equilibrium equations and the tire vertical load equation, side slip angle equation, longitudinal acceleration and slip rate equation. However, the equilibrium equation cannot directly use several parameters of the tire in the model. It is necessary to introduce a tire model for connection. The Magic Formula tire model can be used to obtain the tire lateral force expression:

[0099] F x =D·sin{C·arctan[B·xE(B·x-arctan(B·x))]}+S v ;

[0100] Where x = α jk +kF zjk +j, the remaining stiffness factor B, shape factor C, peak factor D, curvature factor E, longitudinal offset S v , coefficients j and k are parameters fitted based on historical test data.

[0101] The tire longitudinal force expression can also be obtained through the Magic Formula tire model:

[0102] F y =D·sin{C·arctan[B·xE(B·x-arctan(B·x))]};

[0103] Where x = λ jk +kF zjk The remaining stiffness factor B, shape factor C, peak factor D, curvature factor E, and coefficient k are parameters fitted based on historical test data.

[0104] By changing the F zjk , α jk , jk By substituting into the Magic Formula tire model, the longitudinal force and lateral force of each tire can be calculated. The Magic Formula tire model further improves the four equilibrium equations in the seven-degree-of-freedom model.

[0105] The moment balance equation around the Z axis in the seven-degree-of-freedom model is transformed and substituted into the vehicle state parameters at the preview position to obtain the second expected yaw rate at the preview position. The second expected yaw rate is:

[0106]

[0107] The above parameters can be obtained by interpreting the parameters in the seven-degree-of-freedom model, which will not be described in detail here.

[0108] The yaw rate is usually used to measure the stability of a vehicle when turning or changing lanes. The first expected yaw rate and the second expected yaw rate of the preview position can be calculated, and by judging whether the first expected yaw rate and the second expected yaw rate are within a preset range, it can be judged whether the vehicle is in a stable state at the preview position. When the first expected yaw rate or the second expected yaw rate is outside the preset range, the yaw moment of the vehicle can be controlled at the current position of the vehicle, thereby controlling the braking torque of the vehicle to make the vehicle reach a stable state. By predicting the first expected yaw rate and the second expected yaw rate of the vehicle at the preview position, the unstable behavior of the vehicle can be predicted in advance, thereby providing a smoother and more comfortable driving experience. It can also serve as a reference for evaluating the stability and safety of the vehicle in emergency obstacle avoidance, high-speed turning, etc.

[0109] S13: Determine a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate.

[0110] The yaw moment refers to the moment acting on the vehicle to rotate the vehicle around the vertical axis (Z axis).

[0111] After determining the first expected yaw rate and the second expected yaw rate of the vehicle, the yaw moment of the vehicle can be determined according to the first expected yaw rate. Alternatively, the yaw moment of the vehicle can be determined according to the second expected yaw rate. For example, when the first expected yaw rate or the second expected yaw rate is greater than a certain threshold, the yaw moment that the vehicle needs to control can be reduced to reduce the expected yaw rate of the vehicle, so that the vehicle reaches a stable state and reduces the risk of rollover of the vehicle. Alternatively, when the first expected yaw rate or the second expected yaw rate is less than a certain threshold, the vehicle cannot turn in time. At this time, the yaw moment that the vehicle needs to control can be increased to increase the expected yaw rate of the vehicle, so that the vehicle can turn in time.

[0112] Furthermore, in order to ensure that the vehicle is always in a stable state and reduce the risk of the vehicle rolling over, it is also possible to first determine whether the vehicle is in a stable state through a preset range. When the first expected yaw angular velocity or the second expected yaw angular velocity is outside the preset range, it can be determined that if the vehicle operation is controlled based on the current operating parameters of the vehicle, the vehicle may be in an unstable state at the preview position and may be at risk of rolling over. Specifically, the yaw moment of the vehicle can be determined based on the first expected yaw angular velocity or the second expected yaw angular velocity. The tire braking torque that the vehicle needs to control is calculated through the yaw moment of the vehicle, and the tire braking torque is intervened at the current position of the vehicle to keep the vehicle in a stable state and avoid the vehicle from being unstable at the preview position.

[0113] Then, based on the first expected yaw rate or the second expected yaw rate, the step of determining the yaw moment of the vehicle includes:

[0114] In response to the first expected yaw rate or the second expected yaw rate reaching a preset condition, a yaw moment of the vehicle is determined based on the first expected yaw rate or the second expected yaw rate.

[0115] The preset condition indicates that the vehicle is in an unstable state, and the preset condition includes: the first expected yaw angular velocity or the second expected yaw angular velocity is outside a preset range, and the preset range is set according to the actual situation.

[0116] When the first expected yaw rate and the second expected yaw rate are both within the preset range, -k<γ<k, it is determined that the vehicle is in a stable state at the preview position, wherein k can be calibrated according to historical data of actual vehicle tests.

[0117] When the first expected yaw angular velocity or the second expected yaw angular velocity is outside the preset range, it is determined that the vehicle is showing an unstable trend in the preview position, and intervention can be made at the current position of the vehicle to control the yaw moment of the vehicle, thereby controlling the braking torque of the vehicle to stabilize the vehicle, avoid the vehicle from being unstable in the preview position, and reduce the risk of vehicle rollover.

[0118] The following is a detailed description of the determination of the yaw moment of the vehicle:

[0119] The moment of inertia of the vehicle around a preset coordinate system may be obtained first. Then, the rate of change of the difference between the first expected yaw rate or the second expected yaw rate and a preset threshold value per unit time is calculated to obtain the yaw rate change rate. Then, the yaw moment of the vehicle is determined according to the product of the yaw rate change rate and the moment of inertia.

[0120] When the vehicle shows an unstable trend at the preview position and without yaw torque control intervention, the first expected yaw rate and the second expected yaw rate are equal and both are outside the preset range. At this time, the yaw torque that the vehicle needs to control can be calculated, and the expected yaw rate of the vehicle can be controlled within the preset range through yaw torque intervention to keep the vehicle in a stable state. The minimum control amount is |γ|-k, and the yaw torque that needs to be controlled can be determined based on the control amount as:

[0121]

[0122] Where M is the yaw moment, γ is the second expected yaw angular velocity, k is the preset threshold, I z is the moment of inertia of the vehicle around the preset coordinate system, that is, the moment of inertia of the vehicle around the Z axis. When the vehicle does not perform yaw moment control intervention, the first expected yaw rate and the second expected yaw rate are equal, and the yaw moment can be calculated by the first expected yaw rate. Or the second expected yaw rate When the vehicle performs one or more yaw moment control interventions, the first expected yaw rate and the second expected yaw rate are not equal, and the yaw moment can be calculated by the second expected yaw rate Perform calculations.

[0123] The longitudinal moment distribution is calculated based on the calculated yaw moment, and the braking moment is controlled by unilateral braking. Therefore, it actually only affects the braking force of the longitudinal tire on one side, and does not consider the equal distribution of the front and rear tires in other cases. When the vehicle has an unstable trend to the right in the preview position, the braking force of the right longitudinal tire can be set to 0, and the braking forces of the front and rear longitudinal tires on the left are equal:

[0124]

[0125] You can get:

[0126]

[0127] When the vehicle tends to be unstable to the left in the preview position, the left longitudinal tire braking force can be set to 0, and the front and rear longitudinal tire braking forces on the right side are equal:

[0128]

[0129] You can get:

[0130]

[0131] S14: driving the vehicle according to the yaw moment.

[0132] The tire braking force is determined by the yaw moment obtained by the above formula, and the vehicle is driven by the tire braking force. xfl 、F xfr or F xrl 、F xrr Substitute into the above calculation formula of the second expected yaw rate:

[0133]

[0134] The above parameters can be obtained by interpreting the parameters in the seven-degree-of-freedom model, which will not be described in detail here.

[0135] The expected yaw rate γ′ of the preview position after yaw moment control is recalculated, and γ′ is compared with the preset range (-k, k). If γ′ is still outside the preset range, the above process is repeated until -k<γ′<k.

[0136] The present application determines the preview position of the vehicle, determines the yaw moment of the vehicle based on the two expected yaw angular velocities of the vehicle at the preview position, and during the operation of the vehicle, uses the real-time status of the vehicle and the road conditions ahead to predict and adjust the yaw moment of the vehicle in advance, thereby optimizing the dynamic response of the vehicle to sudden situations such as turning or obstacle avoidance, reducing the risk of vehicle rollover, and enhancing the stability and safety of the vehicle.

[0137] Combine the following Figure 4 , the vehicle control method is further illustrated by examples:

[0138] First, the vehicle camera identifies the road conditions of the current road and calculates the desired path through the path planning algorithm. After the desired path is determined, the vehicle's preview position is determined based on the vehicle's current operating parameters and the desired path. For example, the actual preview distance and preview position can be determined by the road curvature, vehicle lateral deviation, and heading deviation.

[0139] Then, the first expected yaw rate of the vehicle is calculated based on the expected yaw rate formula, and a seven-degree-of-freedom vehicle model corresponding to the current operating parameters is established based on the current operating parameters of the vehicle. The seven-degree-of-freedom vehicle model includes the vertical load equations of each tire, the side slip angle equations of each tire, and the slip rate equations of each tire. The vertical load equations of each tire, the side slip angle equations of each tire, and the slip rate equations of each tire can be substituted into the magic formula to obtain the tire lateral force expression and tire longitudinal force expression corresponding to the current operating parameters, and then the tire lateral force expression and tire longitudinal force expression are substituted into the balance equation in the seven-degree-of-freedom model to obtain the second expected yaw rate of the vehicle.

[0140] When the first expected yaw rate or the second expected yaw rate is outside the preset range, it can be determined that the vehicle has an unstable trend at the preview position. The yaw moment that the vehicle needs to control can be calculated by the first expected yaw rate or the second expected yaw rate, and then the yaw moment is corrected by PID (Proportional-Integral-Derivative), and the tire braking torque of the vehicle is calculated by the corrected yaw moment, and finally the vehicle is driven by the tire braking torque.

[0141] After the vehicle is controlled by the tire braking torque, the second expected yaw rate of the vehicle after the last tire braking torque control is repeatedly calculated and iterated until the second expected yaw rate is within a preset range. At this time, it is determined that the vehicle can reach a stable state at the preview position, and the yaw torque that needs to be controlled for the vehicle is zero, and no additional yaw torque control of the vehicle is required.

[0142] It should be understood that although Figure 1 , Figure 4 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 , Figure 4At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0143] like Figure 5 As shown, the present application also provides a vehicle control system, comprising:

[0144] A first determination module 51 is used to determine a desired path and obtain current operating parameters of the vehicle;

[0145] a second determination module 52, configured to determine a preview position of the vehicle according to the current operating parameters and the expected path, and determine a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position; the first expected yaw rate is determined by the longitudinal speed and wheelbase of the vehicle, and the second expected yaw rate is determined by the current operating parameters of the vehicle and / or physical parameters of the vehicle;

[0146] a third determining module 53, configured to determine a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate;

[0147] The driving module 54 is used to drive the vehicle to travel according to the yaw moment.

[0148] In one embodiment, the current operating parameter includes the current position of the vehicle; the second determination module 52 is further configured to:

[0149] Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position;

[0150] Determining a preview steering angle of the front wheels of the vehicle at the preview position based on a preset correspondence between the steering angle, the preview distance and the road curvature;

[0151] determining a proportionality factor based on a ratio of a longitudinal speed of the vehicle and a wheelbase of the vehicle;

[0152] determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle;

[0153] The second expected yaw rate is determined based on current operating parameters of the vehicle and / or physical parameters of the vehicle.

[0154] In one embodiment, the second determining module 52 is further configured to:

[0155] The first expected yaw rate is determined according to a product of a tangent value of the preview steering angle and the proportionality coefficient.

[0156] In one embodiment, the third determining module 53 is further configured to:

[0157] In response to the first expected yaw rate or the second expected yaw rate reaching a preset condition, the yaw moment of the vehicle is determined based on the first expected yaw rate or the second expected yaw rate; the preset condition indicates that the vehicle is in an unstable state, and the preset condition includes: the first expected yaw rate or the second expected yaw rate is outside a preset range.

[0158] In one embodiment, the third determining module 53 is further configured to:

[0159] Obtaining the moment of inertia of the vehicle around a preset coordinate system;

[0160] Determine a yaw rate change rate; wherein the yaw rate change rate indicates a rate of change of a difference between the first expected yaw rate or the second expected yaw rate and a preset threshold value per unit time;

[0161] A yaw moment of the vehicle is determined based on the yaw rate change rate and the rotational inertia.

[0162] For the system embodiment, since it basically corresponds to the method embodiment, the relevant parts can refer to the partial description of the method embodiment. The system embodiment described above is only illustrative, wherein the units described as separate components may or may not be physically separated, and the components as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present application solution.

[0163] Figure 6 This is a structural diagram of an electronic device shown in an example embodiment of the present application, the electronic device includes a memory, a processor, and a computer program stored in the memory and used to run on the processor, and the processor implements the control method described in any of the above embodiments when executing the computer program. Figure 6 The electronic device 60 shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0164] like Figure 6As shown, the electronic device 60 may be in the form of a general-purpose computing device, for example, it may be a server device. The components of the electronic device 60 may include, but are not limited to: at least one processor 61, at least one memory 62, and a bus 63 connecting different system components (including the memory 62 and the processor 61).

[0165] The bus 63 includes a data bus, an address bus, and a control bus.

[0166] The memory 62 may include a volatile memory, such as a random access memory (RAM) 621 and / or a cache memory 622 , and may further include a read-only memory (ROM) 623 .

[0167] The memory 62 may also include a program tool 625 (or utility) having a set (at least one) of program modules 624, such program modules 624 including but not limited to: an operating system, one or more application programs, other program modules, and program data, each of which or some combination may include an implementation of a network environment.

[0168] The processor 61 executes various functional applications and data processing by running the computer program stored in the memory 62, such as the control method provided in any of the above embodiments.

[0169] The electronic device 60 may also communicate with one or more external devices 64 (e.g., keyboards, pointing devices, etc.). Such communication may be performed via an input / output (I / O) interface 65. Furthermore, the electronic device 60 may also communicate with one or more networks (e.g., local area networks (LANs), wide area networks (WANs), and / or public networks, such as the Internet) via a network adapter 66. As shown, the network adapter 66 communicates with other modules of the electronic device 60 via a bus 63. It should be understood that, although not shown in the figure, other hardware and / or software modules may be used in conjunction with the electronic device 60, including but not limited to: microcode, device drivers, redundant processors, external disk drive arrays, RAID (disk array) systems, tape drives, and data backup storage systems, etc.

[0170] It should be noted that although several units / modules or sub-units / modules of the electronic device are mentioned in the above detailed description, this division is merely exemplary and not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more units / modules described above can be embodied in one unit / module. Conversely, the features and functions of one unit / module described above can be further divided into multiple units / modules to be embodied.

[0171] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the control method provided in any of the above embodiments is implemented.

[0172] The readable storage medium may include but is not limited to: a portable disk, a hard disk, a random access memory, a read-only memory, an erasable programmable read-only memory, an optical storage device, a magnetic storage device or any suitable combination of the above.

[0173] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0174] An embodiment of the present application also provides a computer program product, including a computer program, which implements any of the control methods described above when executed by a processor.

[0175] Among them, the program code for executing the computer program product of the present application can be written in any combination of one or more programming languages, and the program code can be executed completely on the user device, partially on the user device, as an independent software package, partially on the user device and partially on a remote device, or completely on the remote device.

[0176] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0177] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A vehicle control method, characterized in that: The control method comprises: Determining a desired path and obtaining current operating parameters of the vehicle; Determining a preview position of the vehicle according to the current operating parameters and the expected path, and determining a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position; the first expected yaw rate is determined by a longitudinal speed and a wheelbase of the vehicle, and the second expected yaw rate is determined by current operating parameters of the vehicle and / or physical parameters of the vehicle; determining a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate; The vehicle is driven to travel according to the yaw moment.

2. The control method according to claim 1, characterized in that: The current operating parameters include the current position of the vehicle; Then, determining the preview position of the vehicle and determining a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position according to the current operating parameters and the expected path includes: Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position; Determining a preview steering angle of the front wheels of the vehicle at the preview position based on a preset correspondence between a steering angle, a preview distance, and a road curvature; determining a proportionality factor based on a ratio of a longitudinal speed of the vehicle and a wheelbase of the vehicle; determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle; The second expected yaw rate is determined based on current operating parameters of the vehicle and / or physical parameters of the vehicle.

3. The control method according to claim 2, characterized in that: The determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle comprises: The first expected yaw rate is determined according to a product of a tangent value of the preview steering angle and the proportionality coefficient.

4. The control method according to any one of claims 1 to 3, characterized in that: The determining the yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate includes: In response to the first expected yaw rate or the second expected yaw rate reaching a preset condition, the yaw moment of the vehicle is determined based on the first expected yaw rate or the second expected yaw rate; the preset condition indicates that the vehicle is in an unstable state, and the preset condition includes: the first expected yaw rate or the second expected yaw rate is outside a preset range.

5. The control method according to claim 4, characterized in that: The determining the yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate includes: Obtaining the moment of inertia of the vehicle around a preset coordinate system; Determine a yaw rate change rate; wherein the yaw rate change rate indicates a rate of change of a difference between the first expected yaw rate or the second expected yaw rate and a preset threshold value per unit time; A yaw moment of the vehicle is determined based on the yaw rate change rate and the rotational inertia.

6. A vehicle control system, characterized in that: The control system comprises: A first determination module, used to determine a desired path and obtain current operating parameters of the vehicle; a second determination module, configured to determine a preview position of the vehicle and a first expected yaw rate and a second expected yaw rate of the vehicle at the preview position according to the current operating parameters and the expected path; the first expected yaw rate is determined by a longitudinal speed and a wheelbase of the vehicle, and the second expected yaw rate is determined by a current operating parameter of the vehicle and / or a physical parameter of the vehicle; a third determining module, configured to determine a yaw moment of the vehicle based on the first expected yaw rate or the second expected yaw rate; A driving module is used to drive the vehicle to travel according to the yaw moment.

7. The control system according to claim 6, characterized in that: The current operating parameters include the current position of the vehicle; the second determination module is further used for: Determine a road curvature and an actual preview distance between the current position and the preview position; wherein the road curvature is a road curvature of the desired path at the preview position; Determining a preview steering angle of the front wheels of the vehicle at the preview position based on a preset correspondence between the steering angle, the preview distance and the road curvature; determining a proportionality factor based on a ratio of a longitudinal speed of the vehicle and a wheelbase of the vehicle; determining the first expected yaw rate according to the proportionality coefficient and the preview steering angle; The second expected yaw rate is determined based on current operating parameters of the vehicle and / or physical parameters of the vehicle.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and used to run on the processor, characterized in that: When the processor executes the computer program, the control method according to any one of claims 1 to 5 is implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the control method according to any one of claims 1 to 5 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the control method according to any one of claims 1 to 5 is implemented.

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