Turning control method and turning control system for vehicle, electronic device, vehicle

Abstract

The application discloses a turning control method and system of a vehicle, an electronic device and the vehicle. The turning control method comprises the following steps: determining a safe turning radius of the vehicle according to current scene information and vehicle parameters; determining an actual turning radius of the vehicle according to the vehicle parameters; and controlling the vehicle to turn according to the safe turning radius and the actual turning radius. The vehicle parameters at least include the vehicle speed and an EPS turning angle. According to the turning control method and system of the vehicle, the electronic device and the vehicle, the vehicle can safely turn in the automatic driving scene.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to a turning control method and system of a vehicle, an electronic device and a vehicle. BACKGROUND

[0002] At present, some vehicles can predict the driving trajectory through vehicle-mounted cameras, radars and the like to assist the driver in turning operation.

[0003] However, it is difficult to ensure that the vehicle can actually turn smoothly only according to the predicted driving trajectory, which cannot meet the actual turning control requirements of the vehicle when the vehicle is automatically driven.

[0004] Therefore, improvements are needed to at least partially solve the above problems. SUMMARY

[0005] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the specific embodiment section. The summary section of the present application does not mean to attempt to limit the key features and essential technical features of the claimed technical solutions, nor to attempt to determine the protection scope of the claimed technical solutions.

[0006] In order to at least partially solve the above problems, according to a first aspect of the present application, a turning control method of a vehicle is provided, comprising:

[0007] determining a safe turning radius of the vehicle according to current scene information and vehicle parameters;

[0008] determining an actual turning radius of the vehicle according to the vehicle parameters;

[0009] controlling the vehicle to turn according to the safe turning radius and the actual turning radius;

[0010] wherein the vehicle parameters at least include the vehicle speed and the EPS turning angle of the vehicle.

[0011] Exemplarily, the determining the safe turning radius of the vehicle according to the current scene information and the vehicle parameters comprises:

[0012] determining the scene boundary at the turning position of the vehicle and the perpendicular distance from the turning center of the vehicle to the scene boundary according to the current scene information and the vehicle parameters;

[0013] subtracting a preset safe gap distance from the perpendicular distance, and taking the obtained result as the safe turning radius.

[0014] Exemplarily, the vehicle parameters further include a wheelbase, a front suspension length, a vehicle width, and a kingpin center distance of the vehicle,

[0015] The determining the actual turning radius of the vehicle according to the vehicle parameters comprises:

[0016] determining a steered wheel outer wheel angle of the vehicle according to the EPS angle;

[0017] determining a theoretical turning radius of the vehicle according to the wheelbase, the steered wheel outer wheel angle, the front suspension length, the vehicle width, and the kingpin center distance of the vehicle;

[0018] determining the actual turning radius of the vehicle according to the theoretical turning radius and the vehicle speed.

[0019] Exemplarily, the controlling the vehicle to turn according to the safe turning radius and the actual turning radius comprises:

[0020] when the actual turning radius is greater than or equal to the safe turning radius, adjusting a steering control parameter of the vehicle according to a type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius;

[0021] controlling the vehicle to turn with the reduced actual turning radius.

[0022] Exemplarily, the type of the vehicle is a four-wheel drive vehicle, and the steering control parameter includes the EPS angle and a driving torque or a braking torque of four wheels of the vehicle;

[0023] The adjusting the steering control parameter of the vehicle according to the type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius comprises:

[0024] increasing the EPS angle;

[0025] when the EPS angle reaches a maximum limit value, adjusting the driving torque or the braking torque of the four wheels of the vehicle to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius.

[0026] Exemplarily, the four wheels include an inner front wheel, an outer front wheel, an inner rear wheel, and an outer rear wheel;

[0027] The adjusting the driving torque or the braking torque of the four wheels of the vehicle to change the actual turning radius of the vehicle comprises:

[0028] applying a braking torque to the inner rear wheel or the inner front wheel and applying a driving torque to other wheels except the inner rear wheel or the inner front wheel.

[0029] Exemplarily, a braking torque is applied to the inner rear wheel or the inner front wheel, and a driving torque is applied to the other wheels except the inner rear wheel or the inner front wheel, including:

[0030] obtaining wheel speeds, yaw angular velocities, tire side slip angles and EPS turning angles of the four wheels;

[0031] determining target braking torques and target driving torques according to the wheel speeds, the yaw angular velocities, the tire side slip angles and the EPS turning angles;

[0032] applying the target braking torques to the inner rear wheel or the inner front wheel and applying the target driving torques to the other wheels except the inner rear wheel or the inner front wheel.

[0033] Exemplarily, the vehicle is a four-wheel drive vehicle, and the steering control parameters include front wheel EPS turning angles and rear wheel EPS turning angles;

[0034] the adjusting the steering control parameters of the vehicle according to the steering type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius, including:

[0035] increasing the front wheel EPS turning angles;

[0036] when the front wheel EPS turning angles reach a maximum limit, adjusting the rear wheel EPS turning angles to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius.

[0037] Exemplarily, when the actual turning radius is greater than or equal to the safe turning radius, the method further includes:

[0038] judging whether a difference between the actual turning radius and the safe turning radius is greater than a preset adjustment threshold;

[0039] when the difference between the actual turning radius and the safe turning radius is greater than the preset adjustment threshold, issuing a reminder information, the reminder information being used to remind a driver of the vehicle to manually control the vehicle to turn.

[0040] Exemplarily, the controlling the vehicle to turn according to the safe turning radius and the actual turning radius, including:

[0041] when the actual turning radius is less than the safe turning radius, controlling the vehicle to turn at the actual turning radius.

[0042] According to a second aspect of the present application, a turning control system of a vehicle is provided, including:

[0043] a first determining unit, configured to determine a safe turning radius of the vehicle according to current scene information and vehicle parameters;

[0044] a second determining unit, configured to determine an actual turning radius of the vehicle according to the vehicle parameters;

[0045] a control unit, configured to control the vehicle to turn according to the safe turning radius and the actual turning radius.

[0046] The vehicle parameters at least include a vehicle speed and an EPS angle of the vehicle.

[0047] According to a third aspect of the present application, an electronic device is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the computer program is executed by the processor to implement the turning control method as described above.

[0048] According to a fourth aspect of the present application, a vehicle is provided, comprising the turning control system as described above or the electronic device as described above.

[0049] The turning control method of the vehicle, the turning control system, the electronic device and the vehicle according to the present application can determine the safe turning radius and the actual turning radius of the vehicle according to the current scene information and the vehicle parameters, and then control the vehicle to turn, so as to meet the turning control requirement of the vehicle in automatic driving and effectively improve the safety and success rate of the vehicle turning. BRIEF DESCRIPTION OF DRAWINGS

[0050] The following drawings for the present application are hereby incorporated into the present application as part of the present application for the purpose of understanding the present application. The embodiments of the present application and the description thereof shown in the drawings are used to explain the devices and principles of the present application. In the drawings,

[0051] Figure 1 a flowchart of the turning control method of the vehicle according to an embodiment of the present application;

[0052] Figure 2 a schematic diagram of the turning process when the actual turning radius of the vehicle is less than the safe turning radius;

[0053] Figure 3 a schematic diagram of the turning process when the actual turning radius of the vehicle is greater than the safe turning radius;

[0054] Figure 4 a schematic diagram of the model predictive control principle.

[0055] Explanation of Reference Signs:

[0056] 10-vehicle, 20-scene boundary;

[0057] FL - front outer wheel, FR - front inner wheel, RL - rear outer wheel, RR - rear inner wheel;

[0058] O - turning circle center, D L - safe turning radius, L - vertical distance, d - safe clearance distance, r B - actual turning radius, O' - changed turning circle center, R B - changed actual turning radius. DETAILED DESCRIPTION

[0059] In the following description, numerous specific details are set forth to provide a more thorough understanding of the present application. However, it will be apparent to one of skill in the art that the present application can be practiced without one or more of these details. In other instances, well-known features have not been described in order to avoid obscuring the present application.

[0060] It should be understood that the present application can be carried out in various forms without departing from the spirit or essential characteristics thereof. Rather, the present application is to cover all possible modifications and equivalents falling within the spirit and scope of the application. In the drawings, the size and relative sizes of layers and regions can be exaggerated for clarity. Like reference numerals can represent like elements throughout.

[0061] It should be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present application.

[0062] Spatially relative terms, such as "beneath", "below", "lower", "under", "above", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device described is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0063] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting thereof. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0064] Reference will now be made to the drawings, wherein Figures 1-4 A turning control method of a vehicle according to an embodiment of the present application is exemplarily illustrated, which comprises the following steps:

[0065] S100: determining a safe turning radius of the vehicle according to current scene information and vehicle parameters.

[0066] Specifically, the current scene information can include the position (orientation relative to the vehicle 10), shape, size and distance from the vehicle 10 of the objects around the vehicle 10, and can also include the environmental boundaries around the vehicle 10, road line positions, traffic signs, etc. The vehicle parameters can include the vehicle speed and EPS (Electrical Power Steering) steering angle of the vehicle 10, etc. In the embodiments of the present application, the vehicle 10 is provided with a radar and a camera, the radar is used to obtain the position, shape, size and distance from the vehicle 10 of the objects around the vehicle 10, and the camera is used to obtain the environmental boundaries around the vehicle 10, road line positions, traffic signs, etc. The radar can be one or more of a laser radar, a millimeter wave radar and an ultrasonic radar. The vehicle 10 is also provided with a vehicle speed sensor and an EPS sensor, which are respectively used to obtain the vehicle speed and the EPS steering angle of the vehicle 10. In the embodiments of the present application, the EPS steering angle can refer to the steering wheel steering angle, which corresponds to the angle of the front wheel deflection driven by the electric power steering system. In some embodiments, the EPS steering angle can also refer directly to the angle of the front wheel deflection driven by the electric power steering system. In the embodiments of the present application, the four wheels of the vehicle 10 are respectively arranged on the front and rear axles of the vehicle 10, and when the vehicle 10 turns, the side of the vehicle 10 towards the turning direction is defined as the inner side, and the front wheel and the rear wheel on the inner side of the vehicle 10 are respectively defined as the inner front wheel FR and the inner rear wheel RR, and the side of the vehicle 10 away from the turning direction is defined as the outer side, and the front wheel and the rear wheel on the outer side of the vehicle 10 are respectively defined as the outer front wheel FL and the outer rear wheel RL. In the embodiments of the present application, the vehicle 10 is provided with a vehicle control system, which is used to control the vehicle 10 to turn according to the safe turning radius of the vehicle 10. Figure 2In the embodiment, when the vehicle 10 turns right, the right side of the vehicle 10 is the inner side, the front wheel and the rear wheel on the right side of the vehicle 10 are the inner front wheel FR and the inner rear wheel RR respectively, the left side of the vehicle 10 is the outer side, and the front wheel and the rear wheel on the left side of the vehicle 10 are the outer front wheel FL and the outer rear wheel RL respectively. When the vehicle 10 turns, the rear wheels (i.e. the inner rear wheel RR and the outer rear wheel RL) of the vehicle 10 do not deflect relative to the vehicle 10, and the front wheels (i.e. the inner front wheel FR and the outer front wheel FL) of the vehicle 10 deflect relative to the vehicle 10 to drive the vehicle 10 to turn. In the embodiment, the vehicle 10 is provided with a data fusion and visualization module, which can be an MCU (Micro Control Unit) or other device with computing processing capability, for performing data fusion on the current scene information obtained by the radar and the camera, and for performing three-dimensional modeling on the vehicle 10 and the objects around the vehicle 10, so that the scene boundary 20 at the turning position of the vehicle 10 can be determined according to the established three-dimensional model. Further, the turning center of the vehicle 10 can be determined according to the current EPS angle of the vehicle 10 obtained by the EPS sensor, and the perpendicular distance L from the turning center to the scene boundary 20 can be obtained. The turning center O of the vehicle 10 can be determined based on Ackerman steering geometry, i.e. after the EPS angle is determined, the angles at which the inner front wheel FR and the outer front wheel FL deflect relative to the inner rear wheel RR and the outer rear wheel RL are also determined, and the turning center O of the vehicle 10 is the intersection of the center axes of the wheels of the vehicle 10 (i.e. the intersection of the center axes of the inner front wheel FR, the outer front wheel FL, the inner rear wheel RR and the outer rear wheel RR), so that the position of the turning center O can be determined accordingly. Further, the data fusion and visualization module can determine the perpendicular distance L from the turning center O to the scene boundary 20 according to the positional relationship between the turning center and the scene boundary 20 in the three-dimensional model. The scene boundary 20 is the boundary of the object on the side of the vehicle 10 away from the turning center. After the perpendicular distance L is determined, the data fusion and visualization module subtracts a preset safety clearance distance d from the perpendicular distance L, and obtains a safety turning radius D L (D L = L - d), and then sends the safety turning radius D L to the vehicle central controller (i.e. the CCU (Central Control Unit)). The safety clearance distance d is the distance that the vehicle 10 needs to maintain at least when turning relative to the scene boundary 20, which is set by a person skilled in the art in advance according to reference factors such as the vehicle shape and radar accuracy. When the actual turning radius r B of the vehicle 10 is less than the safety turning radius D L , the vehicle 10 will not collide with the scene boundary 20 when turning; and when the actual turning radius r B of the vehicle 10 is greater than or equal to the safety turning radius D LWhen the vehicle 10 is turning, there is a risk of collision with the scene boundary 20. In some other embodiments, a separate data fusion and visualization module can not be provided, but the vehicle central controller directly fuses the current scene information obtained by the radar and the camera according to the signals from the camera and the radar, models the vehicle 10 and the objects around the vehicle 10 in three dimensions, and determines the scene boundary 20 at the turning position of the vehicle 10, the vertical distance L from the turning center of the vehicle 10 to the scene boundary 20, and the safe turning radius D according to the established three-dimensional model L .

[0067] S200: According to the vehicle parameters, the actual turning radius of the vehicle 10 is determined. The vehicle parameters further include the wheelbase, the front suspension length, the overall width of the vehicle, and the kingpin center distance.

[0068] Specifically, the vehicle central controller obtains the current vehicle speed and the current EPS angle of the vehicle 10 through the vehicle speed sensor and the EPS sensor, and then determines the outer wheel angle of the steering wheel according to the current EPS angle. In the embodiments of the present application, the outer wheel of the steering wheel is the left front wheel FL, and the outer wheel angle of the steering wheel is the deflection angle of the left front wheel FL. There is a certain correspondence between the EPS angle and the angle of the outer wheel of the steering wheel. After obtaining the current EPS angle, the angle of the outer wheel of the steering wheel can be determined according to the correspondence. Then the vehicle central controller calculates the theoretical turning radius R of the vehicle 10 according to the wheelbase L, the outer wheel angle of the steering wheel θ, the front suspension length C, the overall width K of the vehicle, and the kingpin center distance M through the following formula:

[0069]

[0070] After the theoretical turning radius R is calculated, the actual turning radius r of the vehicle is determined according to the theoretical turning radius R and the current vehicle speed B . Specifically, the theoretical turning radius R can be corrected according to the current vehicle speed to obtain the actual turning radius r of the vehicle 10 B . It should be noted that, under the condition that other conditions remain unchanged, the greater the vehicle speed, the greater the turning radius of the vehicle 10, and the smaller the vehicle speed, the smaller the turning radius of the vehicle 10. Therefore, those skilled in the art can determine the relative relationship between the vehicle speed and the theoretical turning radius according to the actual test results of the vehicle 10 when turning, and then correct the theoretical turning radius R according to the current vehicle speed and the relative relationship to obtain the actual turning radius r of the vehicle 10 under the current vehicle speed and the current EPS angle B . In some embodiments, when the vehicle speed is very low (i.e., when the current vehicle speed is lower than a preset vehicle speed threshold), the theoretical turning radius R can be directly taken as the actual turning radius r B .

[0071] In some other embodiments, the vehicle 10 can acquire the current scene information (including the positions, shapes, sizes and distances of the objects around the vehicle 10) by only radar (such as one or more of laser radar, millimeter wave radar and ultrasonic radar) or only camera (such as one or more of binocular camera, structured light camera and TOF (Time of Flight) camera), and then determine the safe turning radius D of the vehicle 10 according to the current scene information and the vehicle parameters by the vehicle central controller L and the actual turning radius r B .

[0072] S300: Control the vehicle 10 to turn according to the safe turning radius and the actual turning radius.

[0073] Specifically, in the embodiments of the present application, after the vehicle central controller determines the safe turning radius D L and the actual turning radius r B , the safe turning radius D L is compared with the actual turning radius r B .

[0074] Referring to the accompanying Figure 2 , when the actual turning radius r B is less than the safe turning radius D L , the vehicle 10 is controlled to turn at the actual turning radius r B , that is, the vehicle central controller controls the vehicle 10 to continue driving at the current speed and the current EPS turning angle to turn.

[0075] When the actual turning radius r B is greater than or equal to the safe turning radius D L , the steering control parameters of the vehicle 10 are adjusted according to the type of the vehicle 10 to reduce the actual turning radius of the vehicle 10 to be less than the safe turning radius.

[0076] In the embodiments of the present application, the vehicle 10 is a four-wheel independent drive vehicle, which comprises four drive motor controllers, four drive motors and four wheels. Each drive motor controller is configured to independently control the operation of a corresponding drive motor. Each drive motor is configured to independently drive or brake a corresponding wheel (i.e., the four drive motors are configured to drive or brake the inner front wheel FR, the inner rear wheel RR, the outer front wheel FL and the outer rear wheel RL, respectively), for example, to apply a forward torque (same as the rolling direction of the corresponding wheel) or a reverse torque (opposite to the rolling direction of the wheel) to the corresponding wheel to generate a driving force or a braking force. The drive motor can be a wheel-side motor or a hub motor. When the drive motor is a wheel-side motor, it can be connected to the wheel through a transmission and a transmission shaft; when the drive motor is a hub motor, it can be directly coupled to the corresponding wheel, and the transmission and the transmission shaft are omitted. The steering control parameters include an EPS steering angle and a driving torque or a braking torque of the four wheels of the vehicle 10.

[0077] When the actual turning radius r B is greater than or equal to the safe turning radius D L , the vehicle central controller controls the vehicle 10 to gradually increase the current EPS steering angle (i.e., gradually increase the steering wheel steering angle in the turning direction, for example, the electric power steering system can be controlled to drive the front wheel to deflect and the steering wheel to rotate to increase the EPS steering angle), and the actual turning radius r B of the vehicle 10 is gradually reduced at the same time. In this process, it can be determined in real time whether the reduced actual turning radius r B is less than the safe turning radius D L . When the reduced actual turning radius r B is less than the safe turning radius D L , the actual turning radius r B at this time is obtained. The vehicle 10 is controlled to turn at the reduced actual turning radius r B (the actual turning radius r B is less than the safe turning radius D L ), i.e., the vehicle 10 is controlled to travel at the corresponding EPS steering angle and the vehicle speed to turn at the reduced actual turning radius r B .

[0078] Referring to the accompanying drawings, Figure 3 when the actual turning radius r B at the maximum EPS steering angle (i.e., when the steering wheel is turned to the limit position in the turning direction, i.e., when the electric power steering system drives the front wheel to deflect to the limit position in the turning direction) is still greater than or equal to the safe turning radius D L , the actual turning radius r B at the maximum EPS steering angle is determined and compared with the safe turning radius D LThe difference is checked against a first preset adjustment threshold. When the absolute value of this difference is less than or equal to the first preset adjustment threshold, the driving torque or braking torque of the four wheels of vehicle 10 is adjusted to change the actual turning radius r of vehicle 10. B Until the changed actual turning radius R B Less than the safe turning radius D L .

[0079] In this embodiment, the driving torque or braking torque of the four wheels of vehicle 10 is adjusted to change the actual turning radius r of vehicle 10 (when the EPS steering angle reaches its maximum limit). B Specifically, this includes applying braking torque to the inner rear wheel RR and driving torque to the inner front wheel FR, outer front wheel FL, and outer rear wheel RL. That is, the vehicle's central controller increases the braking torque of the inner rear wheel RR through the motor controller and drive motor to reduce its speed; and increases the driving torque of the inner front wheel FR, outer front wheel FL, and outer rear wheel RL. Figure 3 The arrows next to the wheels indicate the magnitude and direction of the current driving torque of the wheels, increasing the rotational speeds of the inner front wheel FR, outer front wheel FL, and outer rear wheel RL. In some embodiments, applying driving torque to the inner front wheel FR, outer front wheel FL, and outer rear wheel RL can refer to increasing the driving torque of any one or both of the inner front wheel FR, outer front wheel FL, and outer rear wheel RL to increase their rotational speed, while maintaining the current driving torque of the remaining wheels unchanged (i.e., maintaining their current rotational speed unchanged). For example, the driving torque of the outer rear wheel RL can be increased to increase its rotational speed, while maintaining the current driving torque of the inner front wheel FR and outer front wheel FL unchanged (i.e., maintaining their current rotational speed unchanged). In some embodiments, applying driving torque to the inner front wheel FR, outer front wheel FL, and outer rear wheel RL can also refer to maintaining the current driving torque of the inner front wheel FR, outer front wheel FL, and outer rear wheel RL unchanged, so that their current rotational speed remains constant. This can change the turning center and turning radius of vehicle 10, with the changed turning center O' being closer to vehicle 10, and the changed actual turning radius R... B Less than the safe turning radius D L Therefore, the vehicle 10 can be controlled to change the actual turning radius R. B Turning is achieved by using adjusted drive and braking torques to rotate the vehicle. In other embodiments, the drive or braking torques of the four wheels of vehicle 10 are adjusted to change the actual turning radius r of vehicle 10. Bmay also include: applying a braking torque to the inner front wheel FR, and applying a driving torque to the inner rear wheel RR, the outer front wheel FL and the outer rear wheel RL, the specific implementation manner is similar to that of applying a braking torque to the inner rear wheel RR, and applying a driving torque to the inner front wheel FR, the outer front wheel FL and the outer rear wheel RL, which will not be repeated here. It should be noted that after the turning circle center changes, the vehicle central controller can determine the vertical distance L of the changed turning circle center O' to the scene boundary again according to the braking torque applied to the inner rear wheel RR and the driving torque applied to the inner front wheel FR, the outer front wheel FL and the outer rear wheel RL, and determine the safe turning radius D again L . The braking torque applied to the inner rear wheel RR and the driving torque applied to the inner front wheel FR, the outer front wheel FL and the outer rear wheel RL need to make the changed actual turning radius R B smaller than the determined safe turning radius D L .

[0080] The braking torque applied to the inner front wheel FR and the driving torque applied to the inner rear wheel RR, the outer front wheel FL and the outer rear wheel RL (or the braking torque applied to the outer front wheel FL and the driving torque applied to the inner rear wheel RR, the inner front wheel FR and the outer rear wheel RL) specifically includes: obtaining the wheel speed, yaw rate, tire side slip angle and EPS angle of the four wheels; then determining the target braking torque and the target driving torque according to the wheel speed, yaw rate, tire side slip angle, EPS angle of the four wheels and the first preset adjustment threshold; and then applying the target braking torque to the inner rear wheel RR and the target driving torque to the inner front wheel FR, the outer front wheel FL and the outer rear wheel RL. Wherein the wheel speed, yaw rate, tire side slip angle and EPS angle of the four wheels can be obtained by the vehicle central controller according to the output signals of the corresponding sensors arranged on the vehicle 10. In the embodiments of the present application, the vehicle central controller inputs the wheel speed, yaw rate, tire side slip angle, EPS angle and first preset adjustment threshold to the model predictive controller, and the model predictive controller calculates the target braking torque and the target driving torque required by each wheel in real time. Wherein the model predictive controller can be MCU (Micro Control Unit, micro processing unit) or other devices with computing processing capability. In some embodiments, the vehicle central controller can also directly calculate the target braking torque and the target driving torque required by each wheel according to the wheel speed, yaw rate, tire side slip angle, EPS angle and first preset adjustment threshold of the four wheels. Specifically, the control amount U k , that is, the driving and braking torque distribution of the four wheels, can be solved by constructing the following optimization objective function J k .

[0081]

[0082] Wherein, Np is the prediction time domain, , and respectively k -Y d k , U k -U ref and U k -U k-1 weighted 2-norm of Y k is the system output at the current time, is the system reference output at the current time. In the same way, the driver desired torque in the prediction horizon is also kept constant. U ref represents the reference four-wheel torque distribution, which is obtained by the longitudinal speed control result, and this term provides a reference target for the objective function, representing the minimization of the control variable, U k represents the control variable at the current time. U k-1 represents the control variable output result of the previous time controller, which is used to reduce the control increment and limit the rate of change of the output result. is the predicted output sequence that satisfies the minimum value of the objective function J. The semi-positive definite matrices Q, R, and T are weight matrices, which are reasonably set according to the control requirements and reflect the importance of each control target. See the attached Figure 4 By establishing a vehicle dynamics model, according to the vehicle parameters and the system control input at the previous time, the control variable in the subsequent prediction horizon can be obtained by solving the objective function under the constraint condition by using a quadratic programming algorithm, and the new control variable at the current time is taken as the system control input, and the optimized control is realized through cyclic iteration calculation.

[0083] After the driving and braking torque distribution of the four wheels is determined (that is, the target braking torque applied to the inner rear wheel RR and the target driving torque applied to the inner front wheel FR, the outer front wheel FL, and the outer rear wheel RL are determined, or the target braking torque applied to the inner front wheel FR and the target driving torque applied to the inner rear wheel RR, the outer front wheel FL, and the outer rear wheel RL are determined), the vehicle central controller outputs corresponding control signals to the corresponding drive motor controllers, and the drive motor controllers control the drive corresponding drive motors to output corresponding torques according to the control signals, so as to generate corresponding target braking torques and target driving torques on corresponding wheels. In the embodiment of the application, the vehicle central controller can obtain the braking torque output by the drive motor corresponding to the inner rear wheel RR through the torque sensor, and determine whether it matches the calculated target braking torque. When the braking torque output by the drive motor is less than the calculated target braking torque (for example, when the drive motor is overheated or damaged), the vehicle central controller can control the hydraulic braking system on the vehicle 10 to apply a braking torque to the inner rear wheel RR, so as to match the braking torque provided to the inner rear wheel with the calculated target braking torque.

[0084] It should be noted that the actual turning radius of the vehicle 10 can only be changed within a certain range by adjusting the driving torque or braking torque of the wheels, and therefore, this adjustment mode can only be performed when the difference between the actual turning radius r B and the safe turning radius D L is less than or equal to a first preset adjustment threshold. That is, the first preset adjustment threshold is the maximum adjustment amount of the turning radius by adjusting the driving or braking torque of the wheels at the current vehicle speed. The first preset adjustment threshold may, for example, be 5-15 cm or other suitable threshold, which can be calibrated by a large number of turning tests on the vehicle. When the difference between the actual turning radius r B and the safe turning radius D L is greater than the first preset adjustment threshold, it indicates that the actual turning radius of the vehicle 10 cannot be adjusted to be less than the safe turning radius D L by adjusting the driving or braking torque of the four wheels of the vehicle 10, that is, the vehicle 10 cannot turn by automatic driving at this time and manual intervention is required. At this time, the vehicle central controller can send a reminder message through one or more of the indicator lights, speakers, and display screens on the vehicle 10. The reminder message can be one or more of light information, sound information, and image information, and the reminder message is used to remind the driver of the vehicle 10 to manually control the vehicle 10 to turn.

[0085] According to the turning control method, the turning control method and the turning control system of the vehicle 10 of the present application, the safe turning radius and the actual turning radius of the vehicle 10 are determined according to the current scene information and the vehicle parameters of the vehicle 10, and then the vehicle 10 is controlled to turn according to the safe turning radius and the actual turning radius. The vehicle 10 can be controlled to turn when the actual turning radius is less than the safe turning radius when the vehicle 10 is automatically driven, which can meet the turning control requirements of the vehicle 10 when the vehicle 10 is automatically driven, and can effectively improve the safety and success rate of the turning of the vehicle 10. When the actual turning radius determined according to the vehicle parameters is greater than the safe turning radius and the difference between the actual turning radius and the safe turning radius is less than the preset adjustment threshold, the turning control method of the present application can reduce the actual turning radius of the vehicle 10 by adjusting the driving or braking torque of the four wheels of the vehicle 10, so that the reduced actual turning radius is less than the safe turning radius, so that the vehicle 10 can still successfully complete the turning under this condition, which significantly improves the turning passability of the vehicle 10 and enables the vehicle 10 to adapt to more automatic turning requirements in more scenarios.

[0086] In some embodiments, the type of the vehicle 10 can be a four wheel steering (4WS) vehicle. The steering control parameters can include a front wheel EPS angle and a rear wheel EPS angle. The front wheel EPS angle can be an angle at which the electric power steering system drives the front wheel to deflect, and the rear wheel EPS angle can be an angle at which the electric power steering system drives the rear wheel to deflect. Four wheel steering refers to a process in which, during steering of a vehicle, four wheels can deflect relative to the vehicle body at the same time, and the rear wheels of a four wheel steering vehicle can deflect in the same direction as the front wheels or in the opposite direction. If the steering direction of the rear wheels is the same as that of the front wheels, it is referred to as a same direction control mode, and the turning radius is larger than that of two wheel steering. If the steering direction of the rear wheels is opposite to that of the front wheels, it is referred to as an opposite direction control mode, and the turning radius is smaller than that of two wheel steering. It should be noted that, for a four wheel steering vehicle, only the front wheels deflect (i.e., the front wheel EPS angle increases) and the rear wheels do not deflect (i.e., the rear wheel EPS angle remains unchanged) in the initial stage of turning, and the determination of the safe turning radius and the actual turning radius is basically the same as that of a four wheel drive vehicle, which will not be described here.

[0087] When the actual turning radius is smaller than the safe turning radius, the vehicle 10 can be controlled to turn at the actual turning radius, i.e., the vehicle central controller controls the vehicle 10 to continue driving at the current speed and the current front wheel EPS angle and rear wheel EPS angle to turn.

[0088] When the actual turning radius is greater than or equal to the safe turning radius, the steering control parameters of the vehicle 10 are adjusted according to the type of the vehicle 10 to reduce the actual turning radius of the vehicle 10 to be smaller than the safe turning radius, which specifically includes:

[0089] The vehicle central controller controls the vehicle 10 to gradually increase the front wheel EPS angle (i.e., the electric power steering system drives the front wheel to further deflect in the turning direction to increase the front wheel EPS angle), and the actual turning radius of the vehicle 10 is gradually reduced synchronously while the front wheel EPS angle is increasing (in this process, the EPS angle of the rear wheel remains unchanged, and the EPS angle of the rear wheel can be 0 degrees). In this process, it is determined in real time whether the reduced actual turning radius is smaller than the safe turning radius. When the reduced actual turning radius is smaller than the safe turning radius, the vehicle 10 is controlled to turn at the reduced actual turning radius, i.e., the vehicle 10 is controlled to drive at the front wheel EPS angle, the rear wheel EPS angle and the vehicle speed corresponding to the reduced actual turning radius to turn.

[0090] When the actual turning radius of the vehicle 10 at the maximum front wheel EPS angle is still greater than or equal to the safe turning radius, it is determined whether the difference between the actual turning radius of the vehicle 10 at the maximum front wheel EPS angle and the safe turning radius is less than or equal to a second preset adjustment threshold. When the difference (in absolute value) is less than or equal to the second preset adjustment threshold, the rear wheel EPS angle of the vehicle 10 is adjusted to change the actual turning radius of the vehicle 10 until the changed actual turning radius is less than the safe turning radius. That is, the EPS angle of the rear wheel of the vehicle 10 is adjusted so that the rear wheel of the vehicle 10 is deflected in the opposite direction of the front wheel of the vehicle 10, for example, when the vehicle 10 turns right, the front wheel of the vehicle 10 is deflected right, and the EPS angle of the rear wheel of the vehicle 10 is adjusted so that the rear wheel of the vehicle 10 is deflected left to change the actual turning radius of the vehicle 10 (the actual turning radius of the vehicle 10 gradually decreases as the deflection angle of the rear wheel increases), until the changed actual turning radius is less than the safe turning radius. Then, the vehicle 10 is controlled to turn at the changed actual turning radius.

[0091] It should be noted that the actual turning radius of the vehicle 10 can be changed only within a certain range by adjusting the rear wheel EPS angle, and therefore, the adjustment can be performed only when the difference between the actual turning radius of the vehicle 10 at the maximum front wheel EPS angle and the safe turning radius is less than or equal to the second preset adjustment threshold. That is, the second preset adjustment threshold is the maximum adjustment amount of the turning radius of the vehicle 10 at the current vehicle speed by adjusting the rear wheel EPS angle. The second preset adjustment threshold can be, for example, 5-15 cm or other appropriate threshold, which can be calibrated by a large number of turning tests on the vehicle.

[0092] When it is determined that the difference between the actual turning radius of the vehicle 10 at the maximum front wheel EPS angle and the safe turning radius is greater than the second preset adjustment threshold, it means that the actual turning radius of the vehicle 10 cannot be adjusted to be less than the safe turning radius by adjusting the rear wheel EPS angle, that is, the vehicle 10 cannot turn by automatic driving at this time, and manual intervention is required. At this time, the vehicle central controller can send a reminder information through one or more of the indicator light, the loudspeaker, and the display screen on the vehicle 10. The reminder information can be one or more of light information, sound information, and image information, which is used to remind the driver of the vehicle 10 to manually control the vehicle 10 to turn.

[0093] The embodiments of the present application also provide a turning control system of a vehicle, which comprises:

[0094] The first determination unit is configured to determine a safe turning radius of the vehicle according to current scene information and vehicle parameters;

[0095] a second determining unit, configured to determine an actual turning radius of the vehicle according to the vehicle parameter;

[0096] a control unit, configured to control the vehicle to turn according to the safe turning radius and the actual turning radius.

[0097] The vehicle parameter at least includes a vehicle speed and an EPS angle of the vehicle.

[0098] Further, the first determining unit is specifically configured to determine a scene boundary at the turning of the vehicle and a perpendicular distance from a turning center of the vehicle to the scene boundary according to the current scene information and the vehicle parameter.

[0099] The perpendicular distance is subtracted by a preset safe clearance distance, and a result obtained is taken as the safe turning radius.

[0100] Further, the vehicle parameter further includes a wheelbase, a front suspension length, a vehicle width and a kingpin center distance of the vehicle, and the second determining unit is specifically configured to determine an outer wheel angle of a steered wheel of the vehicle according to the EPS angle.

[0101] The theoretical turning radius of the vehicle is determined according to the wheelbase, the outer wheel angle of the steered wheel, the front suspension length, the vehicle width and the kingpin center distance.

[0102] The actual turning radius of the vehicle is determined according to the theoretical turning radius and the vehicle speed.

[0103] Further, the control unit is specifically configured to adjust a steering control parameter of the vehicle according to a type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius when the actual turning radius is greater than or equal to the safe turning radius.

[0104] The vehicle is controlled to turn at the reduced actual turning radius.

[0105] Further, the type of the vehicle is a four-wheel drive vehicle, the steering control parameter includes an EPS angle and a driving torque or a braking torque of four wheels of the vehicle, and the control unit is specifically configured to:

[0106] increase the EPS angle;

[0107] when the EPS angle reaches a maximum limit value, adjust the driving torque or the braking torque of the four wheels of the vehicle to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius.

[0108] Further, the four wheels include inner front wheels, outer front wheels, inner rear wheels and outer rear wheels, and the control unit is specifically configured to apply the braking torque to the inner rear wheels or the inner front wheels and apply the driving torque to other wheels except the inner rear wheels or the inner front wheels.

[0109] Further, the control unit is specifically configured to: acquire wheel speeds, yaw angular velocities, tire side slip angles, and EPS turning angles of the four wheels;

[0110] According to the wheel speeds, the yaw angular velocities, the tire side slip angles, and the EPS turning angles, target braking torques and target driving torques are determined;

[0111] The target braking torque is applied to the inner rear wheel or the inner front wheel, and the target driving torque is applied to the other wheels except the inner rear wheel or the inner front wheel.

[0112] Further, the vehicle is a four-wheel drive vehicle, and the steering control parameters include front wheel EPS turning angles and rear wheel EPS turning angles;

[0113] The control unit is specifically configured to: increase the front wheel EPS turning angles;

[0114] When the front wheel EPS turning angles reach the maximum limit, the rear wheel EPS turning angles are adjusted to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius.

[0115] Further, when the actual turning radius is greater than or equal to the safe turning radius, the control unit is specifically configured to: determine whether a difference between the actual turning radius and the safe turning radius is greater than a preset adjustment threshold;

[0116] When the difference between the actual turning radius and the safe turning radius is greater than the preset adjustment threshold, a prompt information is sent, and the prompt information is used to remind a driver of the vehicle to manually control the vehicle to turn.

[0117] Further, the control unit is specifically configured to: when the actual turning radius is less than the safe turning radius, control the vehicle to turn at the actual turning radius.

[0118] The embodiments of the present application also provide an electronic device, which includes a memory and a processor, and the memory stores a computer program, and the computer program is executed by the processor to implement the turning control method.

[0119] The electronic device of the embodiments of the present application can control the vehicle to automatically drive to turn when the computer program corresponding to the above-mentioned turning control method stored in the memory of the electronic device is executed by the processor, and the safety and success rate of the vehicle turning can be effectively improved.

[0120] The embodiments of the present application also provide a vehicle, which includes the above-mentioned turning control system or the above-mentioned electronic device.

[0121] Although example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are intended to be illustrative only and are not intended to limit the scope of the present application. Various modifications and changes can be made thereto by those of ordinary skill in the art without departing from the scope and spirit of the application. It is intended that all such modifications and changes be included within the scope of the application as claimed.

[0122] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware, or a combination of computer software and electronic hardware. Whether the functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

[0123] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure the understanding of the present specification.

[0124] Similarly, it is to be understood that, in order to simplify the present application and to help understand one or more of the inventive aspects, various features of the present application are sometimes grouped together in a single embodiment, figure, or description of related embodiments. However, the method of the present application should not be interpreted as reflecting an intention that the claimed application requires more features than are explicitly recited in each claim. Rather, it is distinguished that the inventive point, as reflected in the corresponding claims, is that the corresponding technical problem can be solved with fewer features than all the features of a certain disclosed single embodiment. Therefore, the claims following the specific embodiments are hereby expressly incorporated into the specific embodiments, wherein each claim itself is a separate embodiment of the present application.

[0125] Those skilled in the art can understand that, except for the mutual exclusivity between features, all features disclosed in the specification (including the accompanying claims, abstract and drawings) and all processes or units of any method or device disclosed thereby can be combined in any combination. Unless explicitly stated otherwise, each feature disclosed in the specification (including the accompanying claims, abstract and drawings) can be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0126] Furthermore, those skilled in the art will recognize that, in the practice of the embodiments described herein, certain steps described as sequential in nature are actually performed in parallel. Moreover, those skilled in the art will appreciate that the exemplary embodiments described herein can be practiced with modification and alteration and are not limited to the above-described embodiments. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

[0127] It should be noted that the foregoing embodiments are illustrative rather than limiting, and that modifications can be made by those skilled in the art without departing from the scope of the appended claims.

Claims

1. A turning control method of a vehicle, characterized by, The method comprises: determining a safe turning radius of the vehicle according to current scene information and vehicle parameters; determining an actual turning radius of the vehicle according to the vehicle parameters; controlling the vehicle to turn according to the safe turning radius and the actual turning radius; wherein the vehicle parameters at least include a vehicle speed and an EPS angle of the vehicle; wherein the determining the safe turning radius of the vehicle according to the current scene information and the vehicle parameters comprises: determining a scene boundary at a turning position of the vehicle and a perpendicular distance from a turning center of the vehicle to the scene boundary according to the current scene information and the vehicle parameters; subtracting a preset safe clearance distance from the perpendicular distance, and taking a result obtained as the safe turning radius; wherein the vehicle parameters further include a wheelbase, a front suspension length, a vehicle width and a kingpin center distance of the vehicle, the determining the actual turning radius of the vehicle according to the vehicle parameters comprises: determining an outer wheel turning angle of a steered wheel of the vehicle according to the EPS angle; determining a theoretical turning radius of the vehicle according to the wheelbase, the outer wheel turning angle of the steered wheel, the front suspension length, the vehicle width and the kingpin center distance; determining the actual turning radius of the vehicle according to the theoretical turning radius and the vehicle speed.

2. The turning control method according to claim 1, wherein the controlling the vehicle to turn according to the safe turning radius and the actual turning radius comprises: when the actual turning radius is greater than or equal to the safe turning radius, adjusting a steering control parameter of the vehicle according to a type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius; and controlling the vehicle to turn with the reduced actual turning radius.

3. The turning control method according to claim 2, wherein the type of the vehicle is a four-wheel drive vehicle, and the steering control parameter includes the EPS angle and driving torque or braking torque of four wheels of the vehicle; the adjusting the steering control parameter of the vehicle according to the type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius comprises: increasing the EPS angle; and when the EPS angle reaches a maximum limit value, adjusting the driving torque or braking torque of the four wheels of the vehicle to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius.

4. The turning control method according to claim 3, wherein the four wheels include an inner front wheel, an outer front wheel, an inner rear wheel and an outer rear wheel; the adjusting the driving torque or braking torque of the four wheels of the vehicle to change the actual turning radius of the vehicle comprises: applying a braking torque to the inner rear wheel or the inner front wheel, and applying a driving torque to other wheels except the inner rear wheel or the inner front wheel.

5. The turning control method according to claim 4, wherein the applying the braking torque to the inner rear wheel or the inner front wheel, and the applying the driving torque to other wheels except the inner rear wheel or the inner front wheel, comprise: applying a braking torque to the inner rear wheel or the inner front wheel, and applying a driving torque to the outer front wheel and the outer rear wheel. acquire wheel speeds, yaw rate, tire side slip angle and EPS rotation angle of four wheels of the vehicle; determine target braking torque and target driving torque according to the wheel speeds, the yaw rate, the tire side slip angle and the EPS rotation angle; apply the target braking torque to the inner rear wheel or the inner front wheel and apply the target driving torque to other wheels except the inner rear wheel or the inner front wheel. 6.The turning control method according to claim 2, wherein the vehicle is a four-wheel drive vehicle, and the steering control parameters include a front wheel EPS rotation angle and a rear wheel EPS rotation angle. The adjusting the steering control parameters of the vehicle according to the steering type of the vehicle to reduce the actual turning radius of the vehicle to be less than the safe turning radius includes: increasing the front wheel EPS rotation angle; when the front wheel EPS rotation angle reaches a maximum limit value, adjusting the rear wheel EPS rotation angle to change the actual turning radius of the vehicle until the changed actual turning radius is less than the safe turning radius. 7.The turning control method according to claim 2, wherein when the actual turning radius is greater than or equal to the safe turning radius, the method further includes: judging whether a difference between the actual turning radius and the safe turning radius is greater than a preset adjustment threshold value; when the difference between the actual turning radius and the safe turning radius is greater than the preset adjustment threshold value, issuing a prompt information, the prompt information being used to remind a driver of the vehicle to manually control the vehicle to turn. 8.The turning control method according to claim 1, wherein the controlling the vehicle to turn according to the safe turning radius and the actual turning radius includes: when the actual turning radius is less than the safe turning radius, controlling the vehicle to turn at the actual turning radius. The turning control system is used to implement the control method in any one of claims 1-8, and the turning control system includes: a first determining unit configured to determine a safe turning radius of the vehicle according to current scene information and vehicle parameters; a second determining unit configured to determine an actual turning radius of the vehicle according to the vehicle parameters; 9. A turning control system of a vehicle characterized by comprising: a control unit configured to control the vehicle to turn according to the safe turning radius and the actual turning radius; wherein the vehicle parameters at least include a vehicle speed and an EPS rotation angle of the vehicle. The computer program is executed by the processor to implement the turning control method in any one of claims 1-8. including: the turning control system according to claim 9 or the electronic device according to claim 10.

10. An electronic device comprising a memory and a processor, said memory having stored thereon a computer program, characterized in that, ​ 11. A vehicle characterized by comprising: ​ ​

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