Four-wheel-drive vehicle turning control method and device, vehicle and storage medium

Abstract

The invention relates to a four-wheel-drive vehicle turning control method and device, a vehicle and a storage medium, and the method comprises the steps: obtaining a current vehicle speed and a steering wheel turning angle when the vehicle turns in a cruise mode; the cruise mode corresponds to a target cruise speed; determining a braking control target wheel according to the steering wheel angle; according to the target cruising speed and the current vehicle speed, the braking force of the braking control target wheel is determined; according to the braking force, the target cruising speed and the current vehicle speed, the torque of a front axle and a rear axle is determined; and controlling the vehicle based on the front and rear axle torques and the braking force. According to the embodiment of the invention, the turning radius of the vehicle can be reduced, so that the turning performance of the vehicle on a narrow road is ensured, and the escape and flexibility of the vehicle are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle chassis control, and in particular to a four-wheel drive vehicle turning control method, a four-wheel drive vehicle turning control device, a vehicle and a storage medium. Background Art

[0002] At present, the maneuverability of automobiles is increasingly valued by drivers in the terminal market; the performance of getting out of trouble on narrow roads is increasingly concerned by terminal drivers. However, current vehicles use braking force to clamp the corresponding wheels to reduce the turning radius. However, this method has a limited control range for shortening the turning radius and cannot effectively shorten the turning radius, resulting in poor turning and getting out of trouble performance on narrow roads. Summary of the invention

[0003] One of the purposes of the present invention is to provide a turning control method for a four-wheel drive vehicle to solve the problem in the prior art that the vehicle has poor turning and escape performance on narrow roads; the second purpose is to provide a turning control device for a four-wheel drive vehicle; the third purpose is to provide a vehicle; and the fourth purpose is to provide a storage medium.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A four-wheel drive vehicle turning control method, the method comprising:

[0006] When the vehicle is in a cruise mode and turns, obtaining a current vehicle speed and a steering wheel angle; the cruise mode corresponds to a target cruise speed;

[0007] Determining a braking control target wheel according to the steering wheel angle;

[0008] Determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0009] determining front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0010] The vehicle is controlled based on the front and rear axle torques and the braking force.

[0011] Optionally, the step of determining the target wheel for braking control according to the steering wheel angle comprises:

[0012] determining a steering direction based on a steering wheel angle;

[0013] In response to the steering direction being left, determining the braking control target wheels to be the left front wheel and the right rear wheel;

[0014] In response to the steering direction being right, the braking control target wheels are determined to be the right front wheel and the left rear wheel.

[0015] Optionally, the step of determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed comprises:

[0016] Calculating the wheel locking speed corresponding to the target cruising speed;

[0017] Calculating a current wheel speed corresponding to the current vehicle speed;

[0018] Calculating a wheel speed deviation between the wheel locking speed and the current wheel speed;

[0019] determining a feed-forward braking force corresponding to the wheel speed deviation;

[0020] Performing closed-loop control on the wheel speed deviation to determine a corrected braking force;

[0021] The braking force of the braking control target wheel is determined by combining the feedforward braking force and the corrected braking force; the braking force of the braking control target wheel is used to control the braking control target wheel to brake.

[0022] Optionally, the step of determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed comprises:

[0023] Calculating a vehicle speed deviation between the target cruising speed and the current vehicle speed;

[0024] determining a feed-forward torque corresponding to the vehicle speed deviation;

[0025] Performing closed-loop control on the vehicle speed deviation to determine a correction torque;

[0026] determining a braking torque based on the braking force;

[0027] Determine the control torque by superimposing the feedforward torque, the correction torque and the braking torque;

[0028] Front and rear axle torques are determined based on the control torque.

[0029] Optionally, the front and rear axle torques include front axle torque and rear axle torque, and the step of determining the front and rear axle torques based on the control torque includes:

[0030] Determining the positive control torque as the front axle torque, wherein the front axle torque is used to control the front axle of the vehicle;

[0031] The reverse control torque is determined as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

[0032] Optionally, the step of determining the braking torque according to the braking force comprises:

[0033] The product of the braking force and the preset wheel radius is determined as the braking torque.

[0034] Optionally, the method further comprises:

[0035] determining a suspension control target wheel according to the steering wheel angle;

[0036] Acquiring a suspension control step value corresponding to the suspension control target wheel;

[0037] Determining a target suspension height of the suspension control target wheel according to the suspension control step value;

[0038] Vehicle control is performed based on the target suspension height.

[0039] Optionally, the suspension control target wheel includes an outer wheel and an inner wheel, and the step of determining the suspension control target wheel according to the steering wheel angle includes:

[0040] determining a steering direction based on a steering wheel angle;

[0041] In response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel;

[0042] In response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0043] Optionally, the step of determining the target suspension height of the suspension control target wheel according to the suspension control step value comprises:

[0044] Acquire the current suspension height of the outer wheel and the current suspension height of the inner wheel;

[0045] Increasing the current suspension height of the outer wheel by the suspension control step value to generate a target suspension height of the outer wheel;

[0046] The current suspension height of the inner wheel is reduced by the suspension control step value to generate a target suspension height of the inner wheel.

[0047] Optionally, the method further comprises:

[0048] determining a rear wheel steering angle according to the steering wheel angle;

[0049] Vehicle control is performed based on the rear wheel steering angle.

[0050] Optionally, the vehicle corresponds to a rear wheel steering ratio, and the step of determining the rear wheel steering angle according to the steering wheel angle comprises:

[0051] The product of the steering wheel angle and the rear wheel steering ratio is determined as the rear wheel steering angle.

[0052] A turning control device for a four-wheel drive vehicle, the device comprising:

[0053] An acquisition module, used to acquire the current vehicle speed and steering wheel angle when the vehicle is in a cruise mode and turns; the cruise mode corresponds to a target cruise speed;

[0054] A wheel determination module, used for determining a target wheel for braking control according to the steering wheel angle;

[0055] A braking force determination module, used to determine the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0056] a torque determination module, configured to determine the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0057] A vehicle control module is used to control the vehicle based on the front and rear axle torques and the braking force.

[0058] A vehicle comprises a processor, a memory and a computer program stored in the memory and capable of running on the processor, wherein the computer program implements the steps of the above-mentioned four-wheel drive vehicle turning control method when executed by the processor.

[0059] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the four-wheel drive vehicle turning control method as described above are implemented.

[0060] Beneficial effects of the present invention:

[0061] The embodiment of the present invention determines the front and rear axle torques and braking forces respectively when the vehicle is in cruise mode and turns; and uses the front and rear axle torques and braking forces to control the vehicle, thereby realizing coordinated control of the vehicle's braking system and drive system, thereby integrating the control of the vehicle's turning in both the lateral and longitudinal directions, reducing the radius of the turn, ensuring the turning line performance on narrow roads, and improving the vehicle's escapeability and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 A flowchart of a four-wheel drive vehicle turning control method embodiment of the present invention;

[0063] Figure 2 A flowchart of another embodiment of a four-wheel drive vehicle turning control method of the present invention;

[0064] Figure 3A schematic diagram of an outer wheel and an inner wheel of the present invention;

[0065] Figure 4 A schematic diagram of applying a braking force according to the present invention;

[0066] Figure 5 A schematic diagram of suspension height adjustment of the present invention;

[0067] Figure 6 A torque control schematic diagram of the present invention;

[0068] Figure 7 A schematic diagram of rear wheel steering according to the present invention;

[0069] Figure 8 A schematic diagram of an example of a turning control method for a four-wheel drive vehicle according to the present invention;

[0070] Fig. 9 It is a structural block diagram of an embodiment of a turning control device for a four-wheel drive vehicle of the present invention;

[0071] Fig.10 A schematic diagram of a processor and a storage medium of a vehicle embodiment of the present invention;

[0072] Fig.11 A schematic diagram of a computer storage medium embodiment of the present invention. DETAILED DESCRIPTION

[0073] Reference Figure 1 , shows a flowchart of a four-wheel drive vehicle turning control method embodiment of the present invention. The four-wheel drive vehicle turning control method may specifically include the following steps:

[0074] Step 101, when the vehicle is in a cruise mode and turns, obtain the current vehicle speed and steering wheel angle; the cruise mode corresponds to a target cruise speed;

[0075] Before the vehicle is driven, the driver can set the cruise mode through the physical buttons in the vehicle or the human-computer interaction device such as the large entertainment screen in the vehicle, so that when the vehicle is subsequently driven, the cruise mode can be triggered to control the vehicle. Among them, the cruise mode corresponds to a target cruise speed, which is determined based on the speed input by the user. The embodiment of the present invention does not specifically limit the specific size of the target cruise speed.

[0076] When the vehicle is in cruise mode and turns, the function of controlling the vehicle's steering can be triggered, and the vehicle's current speed and steering wheel angle can be obtained through sensors on the vehicle.

[0077] Step 102, determining a target wheel for braking control according to the steering wheel angle;

[0078] The turning condition of the vehicle is determined according to the steering wheel angle, and the braking control target wheel that needs to be controlled by braking force under the turning condition is determined. The braking control target wheel is the wheel that needs to be controlled by braking force when turning.

[0079] Step 103, determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0080] After the braking control target wheel is determined, the braking force to be applied to the braking control target wheel, ie, the braking force of the braking control target wheel, can be determined based on the relationship between the target cruising speed and the current vehicle speed.

[0081] Step 104, determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0082] The front and rear axle torques can also be calculated based on the braking force, the target cruising speed and the current vehicle speed. The front and rear axle torques are the torques required to be applied by the front and rear axles of the vehicle when turning.

[0083] Step 105 , controlling the vehicle based on the front and rear axle torques and the braking force.

[0084] After obtaining the front and rear axle torque and braking force, the front and rear axle torque can be used to control the front and rear axles of the vehicle, and the braking force can be used to control the target wheels to coordinately control the vehicle's braking system and drive system to make a turn.

[0085] The embodiment of the present invention obtains the current vehicle speed and steering wheel angle when the vehicle is in cruise mode and turns; the cruise mode corresponds to a target cruise speed; determines the target wheel for braking control according to the steering wheel angle; determines the braking force of the target wheel for braking control according to the target cruise speed and the current vehicle speed; determines the front and rear axle torques according to the braking force, the target cruise speed and the current vehicle speed; and controls the vehicle based on the front and rear axle torques and the braking force. When the vehicle is in cruise mode and turns, the front and rear axle torques and braking forces are determined respectively; and the front and rear axle torques and braking forces are used to control the vehicle, thereby achieving coordinated control of the vehicle's braking system and drive system, so that the vehicle can be turned in a fusion manner in both the lateral and longitudinal directions, and the radius of the turn can be reduced to ensure the turning line performance on narrow roads and improve the vehicle's escape and flexibility.

[0086] Reference Figure 2 , shows a flowchart of another embodiment of a four-wheel drive vehicle turning control method of the present invention. The four-wheel drive vehicle turning control method may specifically include the following steps:

[0087] Step 201, when the vehicle is in a cruise mode and turns, obtain the current vehicle speed and steering wheel angle; the cruise mode corresponds to a target cruise speed;

[0088] When the vehicle is in cruise mode and turns, the current vehicle speed and steering wheel angle are obtained through sensors on the vehicle. The cruise mode corresponds to a target cruising speed. The vehicle's turn may include a turn that changes the vehicle's driving direction or a turn that changes lanes.

[0089] Step 202, determining a braking control target wheel and a suspension control target wheel according to the steering wheel angle;

[0090] The steering situation of the vehicle is determined according to the steering wheel angle, and the braking control target wheel that needs braking force control and the suspension control target wheel that needs suspension control are determined. That is, the braking control target wheel is the wheel that needs braking force control when turning, and the suspension control target wheel is the wheel that needs suspension control when turning, and the two are not mutually exclusive. A wheel can be a braking force controlled wheel and a suspension controlled wheel at the same time, that is, the wheel needs to control the braking force and suspension at the same time. The wheel can also be only a suspension control target wheel, that is, only the suspension height needs to be controlled without controlling the braking force.

[0091] In an optional embodiment of the present invention, the step of determining the target wheels for braking control based on the steering wheel angle includes: determining the steering direction based on the steering wheel angle; in response to the steering direction being left, determining the target wheels for braking control to be the left front wheel and the right rear wheel; in response to the steering direction being right, determining the target wheels for braking control to be the right front wheel and the left rear wheel.

[0092] In practical applications, when a vehicle turns, it is often defined that when turning left, the steering wheel angle is positive; conversely, when turning right, the steering wheel angle is negative. The steering direction can be first determined based on the magnitude of the steering wheel angle. When the steering direction is left, it can be determined that the vehicle is turning left, and the braking control target wheels can be determined to be the left front wheel and the right rear wheel in response to the steering direction being left. When the steering direction is right, it can be determined that the vehicle is turning right, and the braking control target wheels can be determined to be the right front wheel and the left rear wheel in response to the steering direction being right.

[0093] In an optional embodiment of the present invention, the suspension control target wheel includes an outer wheel and an inner wheel, which can be referred to as Figure 3, the inner wheel is the wheel of the vehicle on the side close to the turning center; correspondingly, the outer wheel is the wheel of the vehicle on the side far from the turning center. The step of determining the suspension control target wheel according to the steering wheel angle includes: determining the steering direction based on the steering wheel angle; in response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel; in response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0094] Accordingly, the steering direction is determined based on the direction of the steering wheel angle. When the steering direction is left, the outer wheels are determined to be the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel. When the steering direction is right, it can be determined that the vehicle is turning right, and in response to the steering direction being right, the outer wheels are determined to be the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0095] Step 203, determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0096] The target cruising speed and the current vehicle speed can be used together to determine the braking force that needs to be applied to the braking control target wheel. When the braking control target wheel turns, the braking force of the corresponding braking control target wheel is applied to the braking control target wheel. For example, Figure 4 Take turning right as an example: the right front wheel and the left rear wheel are controlled to apply brakes to control the braking force of the target wheel, and the vehicle obtains the corresponding turning direction and shortens the turning radius. In addition, when the vehicle turns left, the left front wheel and the right rear wheel are controlled to apply brakes to control the braking force of the target wheel.

[0097] Specifically, the step of determining the braking force of the target wheel under braking control based on the target cruising speed and the current vehicle speed includes: calculating the wheel locking speed corresponding to the target cruising speed; calculating the current wheel speed corresponding to the current vehicle speed; calculating the wheel speed deviation between the wheel locking speed and the current wheel speed; determining the feedforward braking force corresponding to the wheel speed deviation; performing closed-loop control on the wheel speed deviation to determine the corrected braking force; determining the braking force of the target wheel under braking control in combination with the feedforward braking force and the corrected braking force; the braking force of the target wheel under braking control is used to control the target wheel under braking control.

[0098] Based on the vehicle static model parameters corresponding to the vehicle, the vehicle speed and wheel speed can be converted to calculate the wheel lock speed corresponding to the target cruising speed; and the current wheel speed corresponding to the current vehicle speed can be calculated. The wheel speed deviation between the wheel lock speed and the current wheel speed is calculated, and then the wheel speed deviation is used to look up the table to determine the corresponding feedforward braking force of the vehicle under the wheel speed deviation. Then, the wheel speed of the vehicle is closed-loop controlled based on the wheel speed deviation, and the closed-loop control includes but is not limited to PID (proportional-integral-differential) control, fuzzy control, etc. Based on the closed-loop control, a corrected braking force can be determined; then, the corrected braking force is superimposed on the feedforward braking force to determine the braking force of the target wheel under braking control. The braking force of the target wheel under braking control is used to control the braking control target wheel for braking.

[0099] For example, using PID control as a closed-loop control, the braking force of the target wheel of the determined braking control can be calculated by the following formula:

[0100] e2 = vWheel – vWheelTar;

[0101] Ffb=e2*Pgain+∫(e2*Igain);

[0102] Fraw=Fff+Ffb;

[0103] Among them, e2 is the wheel speed deviation, vWheel is the current wheel speed, vWheelTar is the wheel locking speed, Fff is the feedforward braking force, Ffb is the correction braking force, Pgain is the proportional value, Igain is the integral value, and Fraw is the braking force of the target wheel of the braking control.

[0104] Step 204, determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0105] The braking force, target cruising speed and current vehicle speed can be used to control the vehicle's torque and determine the front and rear axle torques.

[0106] Specifically, the step of determining the front and rear axle torques based on the braking force, the target cruising speed and the current vehicle speed includes: calculating the vehicle speed deviation between the target cruising speed and the current vehicle speed; determining the feedforward torque corresponding to the vehicle speed deviation; performing closed-loop control on the vehicle speed deviation to determine the correction torque; determining the braking torque based on the braking force; determining the control torque by superimposing the feedforward torque, the correction torque and the braking torque; and determining the front and rear axle torques based on the control torque.

[0107] First, the speed deviation between the target cruising speed and the current speed can be calculated, and the feedforward torque corresponding to the speed deviation can be determined based on the table lookup method. Then the speed deviation is used for closed-loop control to determine the correction torque. The specific closed-loop control method for closed-loop control using the speed deviation can be the same as the closed-loop control of the braking control, or a different algorithm can be used. Then the braking torque is determined according to the braking force, and the braking torque is the torque that needs to be supplemented when the brake is triggered. By increasing the braking torque, the overall driving torque of the vehicle is avoided from changing due to the applied braking force, resulting in sudden deceleration or stopping. Therefore, the driving torque of the vehicle consumed by braking needs to be compensated to the driving torque controlled by the drive unit, which is beneficial to maintain the stability and smoothness of the cruising speed and improve the driving experience. Then the feedforward torque, the correction torque and the braking torque are superimposed to determine the control torque. The front and rear axle torques are then determined by the control torque.

[0108] Furthermore, the front and rear axle torques include front axle torque and rear axle torque, and the step of determining the front and rear axle torques based on the control torque includes: determining the positive control torque as the front axle torque, and the front axle torque is used to control the front axle of the vehicle; determining the reverse control torque as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

[0109] In practical applications, the front and rear axle torques may include the front axle torque and the rear axle torque. The positive control torque may be determined as the front axle torque, and the front axle of the vehicle may be controlled by the front axle torque; the reverse control torque may be determined as the rear axle torque, and the rear axle of the vehicle may be controlled by the rear axle torque.

[0110] Furthermore, the step of determining the braking torque according to the braking force includes: determining the product of the braking force and a preset wheel radius as the braking torque. Figure 5 As shown, the front axle of the drive system is controlled to have positive torque and the rear axle to have negative torque, so that the vehicle, combined with the steering angle, will form a yaw moment tending to the set steering direction to assist steering.

[0111] For example, PID control can be used as a closed-loop control, and the control torque can be calculated by the following formula:

[0112] e1 = VTar – Vact;

[0113] Mfb=e1*P+∫(e1*I);

[0114] Mbrk = Fraw*r;

[0115] MProp=Mff+Mfb+Mbrk;

[0116] Among them, e1 is the vehicle speed deviation, Vtar is the target cruising speed, Vact is the current vehicle speed, Mfb is the correction torque, P is the proportional value, I is the integral value, Mff is the feedforward torque, Mbrk is the braking torque, Fraw is the braking force, r is the wheel radius, and MProp is the control torque.

[0117] Step 205, obtaining a suspension control step value corresponding to the suspension control target wheel;

[0118] The suspension control step value corresponding to the suspension control target wheel can be determined based on previous experiments or tests. When the suspension height needs to be adjusted, the suspension control step value corresponding to the suspension control target wheel can be obtained. The suspension control step value matching the wheel can be obtained based on the wheel speed.

[0119] Step 206, determining a target suspension height of the suspension control target wheel according to the suspension control step value;

[0120] The suspension control step value is used to adjust the suspension height of the suspension control target wheel to determine the target suspension height.

[0121] Specifically, the suspension control target wheels include an outer wheel and an inner wheel, and the step of determining the suspension control target wheel according to the steering wheel angle includes: determining a steering direction based on the steering wheel angle; in response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel;

[0122] In response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0123] In practical applications, the current suspension height of the outer wheel and the current suspension height of the inner wheel can be obtained through information such as sensors, and the target suspension height can be obtained by adjusting the current suspension heights of the inner and outer wheels. The suspension height of the outer wheel can be increased; the suspension height of the inner wheel can be reduced. That is, the current suspension height of the outer wheel is increased by the suspension control step value to generate the target suspension height of the outer wheel; the current suspension height of the inner wheel is reduced by the suspension control step value to generate the target suspension height of the inner wheel. For example, you can refer to Figure 6 When the vehicle turns right, the current suspension height of the right wheel decreases by the suspension control step value, and the current suspension height of the left wheel increases by the suspension control step value.

[0124] Step 207, determining a rear wheel steering angle according to the steering wheel angle;

[0125] When the vehicle turns, the rear-wheel steering function can also be used. The rear-wheel steering angle can be determined according to the steering wheel angle, thereby controlling the rear-wheel steering.

[0126] Specifically, the vehicle corresponds to a rear wheel steering ratio, and the step of determining the rear wheel steering angle according to the steering wheel angle includes: determining the product of the steering wheel angle and the rear wheel steering ratio as the rear wheel steering angle.

[0127] The vehicle has a preset rear wheel steering ratio based on its chassis structure. The rear wheel steering ratio is the ratio of the rear wheels to follow the front wheels. The product of the steering wheel angle and the rear wheel steering ratio can be calculated and the product is determined as the rear wheel steering angle. The rear wheel steering of the vehicle is controlled by the rear wheel steering angle. Figure 7 As shown, the front and rear wheels steer simultaneously.

[0128] Step 208 , controlling the vehicle based on the rear wheel steering angle, the front and rear axle torques, the braking force, and the target suspension height.

[0129] After determining the rear wheel steering angle, front and rear axle torque, braking force and target suspension height, the rear wheel steering angle can be used to control the vehicle's rear wheels for steering control, the front and rear axle torques can be used to apply corresponding torques to the front and rear axles, braking force is applied to the target wheels for braking control based on the braking force, and the suspension is controlled based on controlling the suspension of the target wheels to reach the target suspension height, thereby cooperatively controlling the vehicle's steering system, suspension system, braking system and drive system for turning.

[0130] The embodiment of the present invention obtains the current vehicle speed and steering wheel angle when the vehicle is in a cruise mode and turns; the cruise mode corresponds to a target cruise speed; the braking control target wheel and the suspension control target wheel are determined according to the steering wheel angle; the braking force of the braking control target wheel is determined according to the target cruise speed and the current vehicle speed; the front and rear axle torques are determined according to the braking force, the target cruise speed and the current vehicle speed; the suspension control target wheel is determined according to the steering wheel angle; the suspension control step value corresponding to the suspension control target wheel is obtained; the target suspension height of the suspension control target wheel is determined according to the suspension control step value; the rear wheel steering angle is determined according to the steering wheel angle; and the vehicle is controlled based on the rear wheel steering angle, the front and rear axle torques, the braking force and the target suspension height. The coordinated control of the vehicle's steering system, suspension system, braking system and drive system is achieved, so that the vehicle can be integrated and controlled to turn in the horizontal, longitudinal and vertical directions of the vehicle, and the radius of the turn is reduced to ensure the turning line performance on narrow roads and improve the vehicle's escape and flexibility. And because the vehicle's steering system, suspension system, braking system and drive system move in coordination during the turning process, the vehicle's turning posture in the lateral, longitudinal and vertical directions is more stable, and the vehicle's driving stability is better; the occupants in the car will not sway left and right due to inertia when turning, thereby improving the comfort of the occupants.

[0131] In order to make the implementation process of the embodiment of the present invention clear to those skilled in the art, an example is used below to illustrate: Figure 8 As shown, it can include

[0132] In the human-computer interaction module, the vehicle is stationary, the brake pedal is displayed as pressed, and the accelerator pedal is not pressed (for safety reasons, otherwise the function setting is not allowed to be triggered). At this time, the driver can set the steering direction and the target cruising speed when turning through the physical buttons or the in-car entertainment screen; at this time, the braking turning control strategy function is activated; for example: turning left (TurnLeft) or right (TurnRight); the cruising speed when turning = 15kph; the set results: steering direction and steering cruising speed are transmitted to the main control module.

[0133] The main control module is mainly responsible for receiving the steering direction and steering cruise speed required by the driver transmitted by the human-computer interaction module A; and then it is responsible for coordinating the cooperative operation of the drive module, brake module, steering module, and active suspension module to achieve the ultimate goal of reducing the turning radius.

[0134] The drive module receives the cruising speed target from the main control module, and then uses the feedforward + feedback method to quickly control the open loop, and then close the loop to stabilize the cruising speed. 1. Determine the actual speed; 2. Set the target speed; Take the right turn scenario as an example: Since the right front wheel FR needs to be locked, the left front wheel is selected as the reference wheel, that is, the actual speed uses the wheel speed of this wheel as the reference.

[0135] The specific operation mode of torque control is:

[0136] 1. According to the deviation e1 between the current actual vehicle speed VAct and the target vehicle speed VTa, the feedforward torque Mff is obtained by looking up the table; 2. The feedback control torque Mfb is obtained by the speed PID closed-loop controller based on the vehicle speed; the specific method is: according to the deviation e1 between the current actual vehicle speed VAct and the target vehicle speed VTa, the proportional (P) and integral (I) values ​​are set respectively, and Mfb is calculated; 3. If the brake is triggered, the braking torque Mbrk is compensated (the subsequent braking module D will introduce how to calculate the braking torque. The purpose of this operation is to avoid the change of the overall driving torque of the vehicle due to the applied braking force, resulting in sudden deceleration or stopping. Therefore, the driving torque of the vehicle consumed by braking needs to be compensated to the driving torque controlled by the drive unit, which is beneficial to maintain the stability and smoothness of the cruising speed and improve the driving experience); the torques controlled by the above three are added together to obtain the final driving torque MProp.

[0137] The braking module applies braking to the inner side of the front axle and the outer side of the rear axle respectively according to the steering direction sent by the main controller, and the maximum degree of locking can be achieved. It is necessary to consider the service life of components such as brakes and tires and the attenuation of braking efficiency caused by overheating of the brakes. It is not advisable to lock for too long, and locking monitoring is required. After a certain period of locking, the braking force needs to be reduced to restore the wheel to a rolling state; a certain slope and wheel speed stability threshold are set for braking force reduction; in the process of reducing the braking force, the wheel speed gradually recovers from the locked state to the rolling trend. When the wheel speed reaches the stability threshold, the braking force increase mode continues to be triggered to the locked state, and so on. The specific implementation method of the locking braking force is as follows: 1. Calculate the deviation between the current actual wheel speed vWheel of the wheel to be braked and the locking target wheel speed vWheelTar (0mps) as e2, and obtain the feedforward braking force Fff according to e2; 2. Set the proportional value (Pgain) and the integral value (Igain) based on the current actual wheel speed of the wheel to be braked and the locking target wheel speed deviation e2, and obtain the braking force Ffb to be applied through the PID algorithm; the final wheel braking force is Fraw.

[0138] The steering module receives the steering direction signal transmitted by the main control module. When the driver turns the steering wheel according to the preset steering direction, the steering module will monitor the driver's actual steering wheel angle in real time. The steering module E coordinates and controls the rear wheel steering angle according to the steering wheel angle to help shorten the turning radius. For example, according to the steering wheel angle Df, the corresponding rear wheel angle Dr is obtained according to the proportion Fac to directly control the rear wheel steering.

[0139] The active suspension module receives the steering direction signal transmitted by the main control module, controls the inner suspension height to be lowered, and the outer suspension height to be raised; at the same time, it increases the suspension stiffness, improves the support, and assists in shortening the turning radius.

[0140] Exit control: When the main control module activates the intelligent turning control strategy, if the driver presses the activation switch to actively turn off the function, the control will be exited; if during the control process, the driver steps on the accelerator pedal, brake pedal, or the driver operates the steering wheel angle opposite to the set steering direction; the system determines that the driver needs to take over the vehicle for some reason, and the intelligent turning control strategy function exits control.

[0141] If the actuator is in a faulty state, the system will be in a degraded state, i.e. it cannot be activated. If the system is in control at this time, it will exit immediately; including but not limited to the following actuators: power drive unit, brake force control unit, 4-wheel speed sensor, steering wheel angle sensor, suspension height sensor, EPS (front wheel steering device), RWS (rear wheel steering device), active suspension controller, etc.

[0142] It should be noted that, for the sake of simplicity, the method embodiments are described as a series of action combinations, but those skilled in the art should be aware that the embodiments of the present invention are not limited by the order of the actions described, because according to the embodiments of the present invention, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions involved are not necessarily required by the embodiments of the present invention.

[0143] Reference Fig. 9 , shows a structural block diagram of an embodiment of a four-wheel drive vehicle turning control device of the present invention, and the four-wheel drive vehicle turning control device may specifically include:

[0144] The acquisition module 901 is used to acquire the current vehicle speed and steering wheel angle when the vehicle is in a cruise mode and turns; the cruise mode corresponds to a target cruise speed;

[0145] A wheel determination module 902 is used to determine a target wheel for braking control according to the steering wheel angle;

[0146] A braking force determination module 903, used to determine the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0147] A torque determination module 904, configured to determine the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0148] The vehicle control module 905 is used to control the vehicle based on the front and rear axle torques and the braking force.

[0149] In an optional embodiment of the present invention, the wheel determination module 902 includes:

[0150] A direction determination submodule, used to determine the steering direction based on the steering wheel angle;

[0151] A first response submodule, configured to determine that the braking control target wheels are the left front wheel and the right rear wheel in response to the steering direction being left;

[0152] The second response submodule is used for determining that the braking control target wheels are the right front wheel and the left rear wheel in response to the steering direction being right.

[0153] In an optional embodiment of the present invention, the braking force determination module 903 includes:

[0154] A first calculation submodule, used for calculating the wheel locking speed corresponding to the target cruising speed;

[0155] A second calculation submodule, used to calculate the current wheel speed corresponding to the current vehicle speed;

[0156] A third calculation submodule, used for calculating a wheel speed deviation between the wheel locking speed and the current wheel speed;

[0157] a feedforward braking force determination submodule, used to determine the feedforward braking force corresponding to the wheel speed deviation;

[0158] A correction braking force determination submodule performs closed-loop control on the wheel speed deviation to determine the correction braking force;

[0159] The first combining module is used to combine the feedforward braking force and the corrected braking force to determine the braking force of the braking control target wheel; the braking force of the braking control target wheel is used to control the braking control target wheel to brake.

[0160] In an optional embodiment of the present invention, the torque determination module 904 includes:

[0161] a fourth calculation submodule, configured to calculate a vehicle speed deviation between the target cruising speed and the current vehicle speed;

[0162] a feedforward torque determination submodule, used to determine a feedforward torque corresponding to the vehicle speed deviation;

[0163] A correction torque determination submodule, used for performing closed-loop control on the vehicle speed deviation to determine the correction torque;

[0164] a braking torque determination submodule, configured to determine the braking torque according to the braking force;

[0165] A superposition submodule, used for superimposing the feedforward torque, the correction torque and the braking torque to determine the control torque;

[0166] The front and rear axle torque determination submodule is used to determine the front and rear axle torques based on the control torque.

[0167] In an optional embodiment of the present invention, the front and rear axle torques include front axle torque and rear axle torque, and the front and rear axle torque determination submodule includes:

[0168] A front axle torque determination unit, used to determine the positive control torque as the front axle torque, wherein the front axle torque is used to control the front axle of the vehicle;

[0169] The rear axle torque determination unit is used to determine the reverse control torque as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

[0170] In an optional embodiment of the present invention, the braking torque determination submodule includes:

[0171] The braking torque determination unit is used to determine the product of the braking force and a preset wheel radius as the braking torque.

[0172] In an optional embodiment of the present invention, the device further comprises:

[0173] A suspension control target wheel determination module, used to determine the suspension control target wheel according to the steering wheel angle;

[0174] A suspension control step value acquisition module, used to acquire a suspension control step value corresponding to the suspension control target wheel;

[0175] A target suspension height determination module, used to determine a target suspension height of the suspension control target wheel according to the suspension control step value;

[0176] The suspension control module is configured to control the vehicle based on the target suspension height.

[0177] In an optional embodiment of the present invention, the suspension control target wheel determination module includes:

[0178] A second steering determination submodule, configured to determine a steering direction based on a steering wheel angle;

[0179] A third response submodule is used for responding that the steering direction is left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel;

[0180] The fourth response submodule is used to respond to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0181] In an optional embodiment of the present invention, the target suspension height determination module includes:

[0182] A current suspension height acquisition submodule, used to acquire the current suspension height of the outer wheel and the current suspension height of the inner wheel;

[0183] A suspension height increasing submodule, used for increasing the current suspension height of the outer wheel by the suspension control step value to generate a target suspension height of the outer wheel;

[0184] The suspension height reduction submodule is used to reduce the current suspension height of the inner wheel by the suspension control step value to generate a target suspension height of the inner wheel.

[0185] In an optional embodiment of the present invention, the device further comprises:

[0186] A rear wheel steering determination module, used to determine a rear wheel steering angle according to the steering wheel angle;

[0187] The rear wheel steering control module is used to control the vehicle based on the rear wheel steering angle.

[0188] In an optional embodiment of the present invention, the vehicle corresponds to a rear wheel steering ratio, and the rear wheel steering determination module includes:

[0189] The rear wheel steering determination submodule is used to determine the product of the steering wheel angle and the rear wheel steering ratio as the rear wheel steering angle.

[0190] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0191] Reference Fig.10 , an embodiment of the present invention further provides a vehicle, comprising:

[0192] A processor 1001 and a storage medium 1002, wherein the storage medium 1002 stores a computer program executable by the processor 1001. When the vehicle is running, the processor 1001 executes the computer program to perform the four-wheel drive vehicle turning control method as described in any one of the embodiments of the present invention.

[0193] The four-wheel drive vehicle turning control method comprises:

[0194] When the vehicle is in a cruise mode and turns, obtaining a current vehicle speed and a steering wheel angle; the cruise mode corresponds to a target cruise speed;

[0195] Determining a braking control target wheel according to the steering wheel angle;

[0196] Determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0197] determining front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0198] The vehicle is controlled based on the front and rear axle torques and the braking force.

[0199] Optionally, the step of determining the target wheel for braking control according to the steering wheel angle comprises:

[0200] determining a steering direction based on a steering wheel angle;

[0201] In response to the steering direction being left, determining the braking control target wheels to be the left front wheel and the right rear wheel;

[0202] In response to the steering direction being right, the braking control target wheels are determined to be the right front wheel and the left rear wheel.

[0203] Optionally, the step of determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed comprises:

[0204] Calculating the wheel locking speed corresponding to the target cruising speed;

[0205] Calculating a current wheel speed corresponding to the current vehicle speed;

[0206] Calculating a wheel speed deviation between the wheel locking speed and the current wheel speed;

[0207] determining a feed-forward braking force corresponding to the wheel speed deviation;

[0208] Performing closed-loop control on the wheel speed deviation to determine a corrected braking force;

[0209] The braking force of the braking control target wheel is determined by combining the feedforward braking force and the corrected braking force; the braking force of the braking control target wheel is used to control the braking control target wheel to brake.

[0210] Optionally, the step of determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed comprises:

[0211] Calculating a vehicle speed deviation between the target cruising speed and the current vehicle speed;

[0212] determining a feed-forward torque corresponding to the vehicle speed deviation;

[0213] Performing closed-loop control on the vehicle speed deviation to determine a correction torque;

[0214] determining a braking torque based on the braking force;

[0215] Determine the control torque by superimposing the feedforward torque, the correction torque and the braking torque;

[0216] Front and rear axle torques are determined based on the control torque.

[0217] Optionally, the front and rear axle torques include front axle torque and rear axle torque, and the step of determining the front and rear axle torques based on the control torque includes:

[0218] Determining the positive control torque as the front axle torque, wherein the front axle torque is used to control the front axle of the vehicle;

[0219] The reverse control torque is determined as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

[0220] Optionally, the step of determining the braking torque according to the braking force comprises:

[0221] The product of the braking force and the preset wheel radius is determined as the braking torque.

[0222] Optionally, the method further comprises:

[0223] determining a suspension control target wheel according to the steering wheel angle;

[0224] Acquiring a suspension control step value corresponding to the suspension control target wheel;

[0225] Determining a target suspension height of the suspension control target wheel according to the suspension control step value;

[0226] Vehicle control is performed based on the target suspension height.

[0227] Optionally, the suspension control target wheel includes an outer wheel and an inner wheel, and the step of determining the suspension control target wheel according to the steering wheel angle includes:

[0228] determining a steering direction based on a steering wheel angle;

[0229] In response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel;

[0230] In response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0231] Optionally, the step of determining the target suspension height of the suspension control target wheel according to the suspension control step value comprises:

[0232] Acquire the current suspension height of the outer wheel and the current suspension height of the inner wheel;

[0233] Increasing the current suspension height of the outer wheel by the suspension control step value to generate a target suspension height of the outer wheel;

[0234] The current suspension height of the inner wheel is reduced by the suspension control step value to generate a target suspension height of the inner wheel.

[0235] Optionally, the method further comprises:

[0236] determining a rear wheel steering angle according to the steering wheel angle;

[0237] Vehicle control is performed based on the rear wheel steering angle.

[0238] Optionally, the vehicle corresponds to a rear wheel steering ratio, and the step of determining the rear wheel steering angle according to the steering wheel angle comprises:

[0239] The product of the steering wheel angle and the rear wheel steering ratio is determined as the rear wheel steering angle.

[0240] The memory may include a random access memory (RAM) or a non-volatile memory, such as at least one disk memory. Optionally, the memory may also be at least one storage device located away from the processor.

[0241] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0242] Reference Fig.11 The embodiment of the present invention further provides a computer-readable storage medium 1101, on which a computer program is stored, and the computer program is executed by a processor to execute the four-wheel drive vehicle turning control method as described in any one of the embodiments of the present invention. The four-wheel drive vehicle turning control method includes:

[0243] When the vehicle is in a cruise mode and turns, obtaining a current vehicle speed and a steering wheel angle; the cruise mode corresponds to a target cruise speed;

[0244] Determining a braking control target wheel according to the steering wheel angle;

[0245] Determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed;

[0246] determining front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed;

[0247] The vehicle is controlled based on the front and rear axle torques and the braking force.

[0248] Optionally, the step of determining the target wheel for braking control according to the steering wheel angle comprises:

[0249] determining a steering direction based on a steering wheel angle;

[0250] In response to the steering direction being left, determining the braking control target wheels to be the left front wheel and the right rear wheel;

[0251] In response to the steering direction being right, the braking control target wheels are determined to be the right front wheel and the left rear wheel.

[0252] Optionally, the step of determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed comprises:

[0253] Calculating the wheel locking speed corresponding to the target cruising speed;

[0254] Calculating a current wheel speed corresponding to the current vehicle speed;

[0255] Calculating a wheel speed deviation between the wheel locking speed and the current wheel speed;

[0256] determining a feed-forward braking force corresponding to the wheel speed deviation;

[0257] Performing closed-loop control on the wheel speed deviation to determine a corrected braking force;

[0258] The braking force of the braking control target wheel is determined by combining the feedforward braking force and the corrected braking force; the braking force of the braking control target wheel is used to control the braking control target wheel to brake.

[0259] Optionally, the step of determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed comprises:

[0260] Calculating a vehicle speed deviation between the target cruising speed and the current vehicle speed;

[0261] determining a feed-forward torque corresponding to the vehicle speed deviation;

[0262] Performing closed-loop control on the vehicle speed deviation to determine a correction torque;

[0263] determining a braking torque based on the braking force;

[0264] Determine the control torque by superimposing the feedforward torque, the correction torque and the braking torque;

[0265] Front and rear axle torques are determined based on the control torque.

[0266] Optionally, the front and rear axle torques include front axle torque and rear axle torque, and the step of determining the front and rear axle torques based on the control torque includes:

[0267] Determining the positive control torque as the front axle torque, wherein the front axle torque is used to control the front axle of the vehicle;

[0268] The reverse control torque is determined as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

[0269] Optionally, the step of determining the braking torque according to the braking force comprises:

[0270] The product of the braking force and the preset wheel radius is determined as the braking torque.

[0271] Optionally, the method further comprises:

[0272] determining a suspension control target wheel according to the steering wheel angle;

[0273] Acquiring a suspension control step value corresponding to the suspension control target wheel;

[0274] Determining a target suspension height of the suspension control target wheel according to the suspension control step value;

[0275] Vehicle control is performed based on the target suspension height.

[0276] Optionally, the suspension control target wheel includes an outer wheel and an inner wheel, and the step of determining the suspension control target wheel according to the steering wheel angle includes:

[0277] determining a steering direction based on a steering wheel angle;

[0278] In response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel;

[0279] In response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

[0280] Optionally, the step of determining the target suspension height of the suspension control target wheel according to the suspension control step value comprises:

[0281] Acquire the current suspension height of the outer wheel and the current suspension height of the inner wheel;

[0282] Increasing the current suspension height of the outer wheel by the suspension control step value to generate a target suspension height of the outer wheel;

[0283] The current suspension height of the inner wheel is reduced by the suspension control step value to generate a target suspension height of the inner wheel.

[0284] Optionally, the method further comprises:

[0285] determining a rear wheel steering angle according to the steering wheel angle;

[0286] Vehicle control is performed based on the rear wheel steering angle.

[0287] Optionally, the vehicle corresponds to a rear wheel steering ratio, and the step of determining the rear wheel steering angle according to the steering wheel angle comprises:

[0288] The product of the steering wheel angle and the rear wheel steering ratio is determined as the rear wheel steering angle.

[0289] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0290] It will be appreciated by those skilled in the art that the embodiments of the present invention may be provided as methods, devices, or computer program products. Therefore, the embodiments of the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the embodiments of the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0291] The embodiments of the present invention are described with reference to the flowcharts and / or block diagrams of the methods, terminal devices (systems), and computer program products according to the embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing terminal device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing terminal device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0292] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing terminal device to operate in a specific manner, so that the instructions stored in the computer readable memory produce a manufactured product including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0293] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal device so that a series of operating steps are executed on the computer or other programmable terminal device to produce a computer-implemented process, thereby providing instructions for executing on the computer or other programmable terminal device to implement the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0294] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A four-wheel drive vehicle turning control method, characterized in that: The method comprises: When the vehicle is in a cruise mode and turns, obtaining a current vehicle speed and a steering wheel angle; the cruise mode corresponds to a target cruise speed; Determining a braking control target wheel according to the steering wheel angle; Determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed; determining front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed; The vehicle is controlled based on the front and rear axle torques and the braking force.

2. The method according to claim 1, characterized in that The step of determining the target wheel for braking control according to the steering wheel angle comprises: determining a steering direction based on a steering wheel angle; In response to the steering direction being left, determining the braking control target wheels to be the left front wheel and the right rear wheel; In response to the steering direction being right, the braking control target wheels are determined to be the right front wheel and the left rear wheel.

3. The method according to claim 2, characterized in that The step of determining the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed comprises: Calculating the wheel locking speed corresponding to the target cruising speed; Calculating a current wheel speed corresponding to the current vehicle speed; Calculating a wheel speed deviation between the wheel locking speed and the current wheel speed; determining a feed-forward braking force corresponding to the wheel speed deviation; Performing closed-loop control on the wheel speed deviation to determine a corrected braking force; The braking force of the braking control target wheel is determined by combining the feedforward braking force and the corrected braking force; the braking force of the braking control target wheel is used to control the braking control target wheel to brake.

4. The method according to claim 1, characterized in that: The step of determining the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed comprises: Calculating a vehicle speed deviation between the target cruising speed and the current vehicle speed; determining a feed-forward torque corresponding to the vehicle speed deviation; Performing closed-loop control on the vehicle speed deviation to determine a correction torque; determining a braking torque based on the braking force; Determine the control torque by superimposing the feedforward torque, the correction torque and the braking torque; Front and rear axle torques are determined based on the control torque.

5. The method according to claim 4, characterized in that The front and rear axle torques include front axle torque and rear axle torque, and the step of determining the front and rear axle torques based on the control torque includes: Determining the positive control torque as the front axle torque, wherein the front axle torque is used to control the front axle of the vehicle; The reverse control torque is determined as the rear axle torque, and the rear axle torque is used to control the rear axle of the vehicle.

6. The method according to claim 4, characterized in that The step of determining the braking torque according to the braking force comprises: The product of the braking force and the preset wheel radius is determined as the braking torque.

7. The method according to claim 1, characterized in that The method further comprises: determining a suspension control target wheel according to the steering wheel angle; Acquiring a suspension control step value corresponding to the suspension control target wheel; Determining a target suspension height of the suspension control target wheel according to the suspension control step value; Vehicle control is performed based on the target suspension height.

8. The method according to claim 7, characterized in that The suspension control target wheel includes an outer wheel and an inner wheel, and the step of determining the suspension control target wheel according to the steering wheel angle includes: determining a steering direction based on a steering wheel angle; In response to the steering direction being left, the outer wheels are the right front wheel and the right rear wheel, and the inner wheels are the left front wheel and the left rear wheel; In response to the steering direction being right, the outer wheels are the left front wheel and the left rear wheel, and the inner wheels are the right front wheel and the right rear wheel.

9. The method according to claim 7, characterized in that: The step of determining the target suspension height of the suspension control target wheel according to the suspension control step value comprises: Acquire the current suspension height of the outer wheel and the current suspension height of the inner wheel; Increasing the current suspension height of the outer wheel by the suspension control step value to generate a target suspension height of the outer wheel; The current suspension height of the inner wheel is reduced by the suspension control step value to generate a target suspension height of the inner wheel.

10. The method according to claim 1, characterized in that The method further comprises: determining a rear wheel steering angle according to the steering wheel angle; Vehicle control is performed based on the rear wheel steering angle.

11. The method according to claim 8, characterized in that The vehicle corresponds to a rear wheel steering ratio, and the step of determining the rear wheel steering angle according to the steering wheel angle comprises: The product of the steering wheel angle and the rear wheel steering ratio is determined as the rear wheel steering angle.

12. A turning control device for a four-wheel drive vehicle, characterized in that: The device comprises: An acquisition module, used to acquire the current vehicle speed and steering wheel angle when the vehicle is in a cruise mode and turns; the cruise mode corresponds to a target cruise speed; A wheel determination module, used for determining a target wheel for braking control according to the steering wheel angle; A braking force determination module, used to determine the braking force of the target wheel of the brake control according to the target cruising speed and the current vehicle speed; a torque determination module, configured to determine the front and rear axle torques according to the braking force, the target cruising speed and the current vehicle speed; A vehicle control module is used to control the vehicle based on the front and rear axle torques and the braking force.

13. A vehicle, characterized in that: The invention comprises a processor, a memory and a computer program stored in the memory and capable of running on the processor, wherein when the computer program is executed by the processor, the steps of the four-wheel drive vehicle turning control method as claimed in any one of claims 1 to 11 are implemented.

14. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the four-wheel drive vehicle turning control method as described in any one of claims 1 to 11 are implemented.

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