Steering method, vehicle and storage medium

Abstract

The invention provides a steering method, a vehicle and a storage medium, the vehicle carries out independent control on each wheel based on an electronic mechanical braking system, and the method comprises the steps that the current steering wheel angle, the current front wheel angle and the brake pedal opening degree of the vehicle are obtained; when the vehicle is in the steering state, whether the vehicle meets a preset steering correction condition or not is judged according to the current steering wheel rotation angle, the current front wheel rotation angle and the brake pedal opening degree; if the vehicle meets the preset steering correction condition, target braking force corresponding to each wheel of the vehicle is calculated according to the current steering wheel rotation angle and the current front wheel rotation angle, and an electronic mechanical braking system is driven to apply the corresponding target braking force to each wheel. According to the method, the problems that under the conditions that the vehicle turns, the vehicle speed is too high and a driver actively steps on a brake, steering of the vehicle is insufficient or excessive, and even potential safety hazards are caused are solved, and the steering safety and the driving stability of the vehicle are improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and more specifically, to a steering method, a vehicle and a storage medium in the field of vehicle technology. Background Art

[0002] With the rapid development of sensor and network communication technology, the level of automobile electronics and intelligence has been greatly improved, and wire control technology has gradually been applied to the field of vehicle technology. The electronic mechanical brake system (EMB) is an important part of the automobile wire control chassis. Its main feature is that the mechanical connection between the brake pedal and the brake is cancelled. The brake control unit is used to process electronic signals and control the system actuator to output the braking force to complete the braking.

[0003] Automobile steering systems are divided into two categories: mechanical steering systems and power steering systems. The mechanical steering system consists of three parts: the steering control mechanism, the steering gear and the steering transmission mechanism. This system uses the driver's physical strength as the steering energy, and all the force transmission parts are mechanical; the power steering system is a steering system that uses both the driver's physical strength and the engine power as the steering energy.

[0004] In the related art, the vehicle is dynamically controlled by monitoring the yaw rate and adjusting the wheel braking force within a limited range to improve the turning performance of the vehicle.

[0005] However, during the turning process, the steering performance of the vehicle is affected by factors such as the steering system, braking system, chassis layout, etc. In the related technology, the braking system of the vehicle cannot achieve independent control of the four wheels, which makes the vehicle prone to turning difficulties and poor flexibility. Especially when the vehicle speed is too fast, the driver suddenly brakes actively, and the vehicle may understeer or oversteer due to emergency braking, and even cause safety hazards, which needs to be solved urgently. Summary of the invention

[0006] The present application provides a steering method, a vehicle and a storage medium. The method can effectively prevent the vehicle from understeering or oversteering, or even causing safety hazards when the vehicle speed is too fast and the driver actively steps on the brakes during the steering process. The method realizes an independent control method for the four-wheel braking force, so that the vehicle can steer according to the driver's operating expectations, greatly improving the safety of vehicle steering and driving stability.

[0007] In a first aspect, a steering method is provided, in which a vehicle independently controls each wheel based on an electronic mechanical braking system, the method comprising: obtaining a current steering wheel angle, a current front wheel angle, and a brake pedal opening of the vehicle; when the vehicle is in a steering state, judging whether the vehicle satisfies a preset steering correction condition based on the current steering wheel angle, the current front wheel angle, and the brake pedal opening; if the vehicle satisfies the preset steering correction condition, calculating a target braking force corresponding to each wheel of the vehicle based on the current steering wheel angle and the current front wheel angle, and driving the electronic mechanical braking system to apply the corresponding target braking force to each wheel.

[0008] Through the above technical solution, the present application can determine whether the current vehicle is in a steering state, and comprehensively determine whether the current vehicle can output the driver's control expectations based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, as well as the body state and other data. If the current vehicle state parameters meet the correction conditions preset in the present application, the target braking force corresponding to each wheel is obtained by calculation. Thus, the present application can obtain the current vehicle's driving state and body parameters to determine the vehicle's steering state, and calculate the target braking force of each wheel according to the steering state, perform vehicle steering correction, and realize the independent control method of the four-wheel braking force, so that the vehicle can steer according to the driver's control expectations, greatly improving the safety of vehicle steering and driving stability.

[0009] In combination with the first aspect, in certain possible implementations, after determining whether the vehicle satisfies the preset steering correction condition based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, it also includes: if the current vehicle does not meet the preset steering correction condition, braking the vehicle according to the braking force corresponding to the brake pedal opening.

[0010] Through the above technical solution, this application presets the conditions for judging whether active intervention in steering control is required. If the current vehicle does not meet the preset steering correction conditions, there is no need to intervene in the steering of the vehicle, and the vehicle can be braked according to the braking force corresponding to the current brake pedal opening. Therefore, this application can not start the vehicle steering correction strategy when the current vehicle steering action meets the standard, so as to avoid increasing the computing load of the braking system, improve the driver's experience, and improve the intelligence of the vehicle.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the target braking force corresponding to each wheel of the vehicle is calculated based on the current steering wheel angle and the current front wheel angle, including: obtaining the current speed of the vehicle, and calculating the target yaw angle of the vehicle based on the current speed and the current steering wheel angle; based on the target yaw angle, the current brake pedal opening and the current front wheel angle, searching a preset braking force calibration table to obtain the target braking force corresponding to each wheel of the vehicle.

[0012] Through the above technical scheme, the present application calculates the target yaw angle of the vehicle based on the current vehicle speed and the current steering wheel angle, and can accurately judge the direction control and stability of the current vehicle during driving. Furthermore, the present application combines the vehicle driving state data such as the brake pedal opening and the front wheel angle, and obtains the target braking force corresponding to each wheel of the vehicle by pre-calibrating the braking force calibration table. Therefore, the present application can obtain the target braking force corresponding to each wheel, realize independent control of the four-wheel braking force, enable the vehicle to steer according to the driver's operating expectations, and greatly improve the accuracy of the vehicle steering control.

[0013] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, judging whether the vehicle meets the preset steering correction conditions based on the current steering wheel angle, the current front wheel angle and the brake pedal opening includes: calculating the front wheel target angle based on the current steering wheel angle; when the brake pedal opening is greater than the preset opening value, judging whether the vehicle meets the preset steering correction conditions based on the difference between the front wheel target angle and the current front wheel angle.

[0014] Through the above technical solution, the present application provides conditions for judging whether the current vehicle needs steering correction. The present application obtains the target turning angle of the front wheel by calculation. Since the driver turns the steering wheel to shift the front wheel to the left or right, the present application can judge the steering maneuverability and stability of the vehicle based on the data. In addition, the present application can determine the opening of the brake pedal applied by the driver by judging the size of the brake pedal opening, thereby judging that the driver is performing a braking operation. Therefore, the present application can accurately respond to the driver's braking operation and judge whether its steering action needs intervention, effectively improving the safety and stability of the vehicle steering.

[0015] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, judging whether the vehicle meets the preset steering correction condition based on the difference between the front wheel target angle and the current front wheel angle includes: calculating a first difference between the front wheel target angle and the current front wheel angle, and calculating a second difference between the current front wheel angle and the front wheel target angle; if the first difference is greater than a first threshold value, or the second difference is greater than a second threshold value, it is determined that the vehicle meets the preset steering correction condition.

[0016] Through the above technical scheme, the present application makes a difference between the target front wheel angle and the current front wheel angle, and makes a difference between the current front wheel angle and the target angle, and obtains two differences, which are compared with preset thresholds respectively. The present application can accurately determine the steering state of the current vehicle, and then determine whether the current vehicle needs steering correction, so as to achieve precise control of the vehicle steering and greatly improve the pass rate of vehicle steering.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, after calculating the first difference between the front wheel target angle and the current front wheel angle, and calculating the second difference between the current front wheel angle and the front wheel target angle, it also includes: if the first difference is greater than the first threshold value, it is determined that the vehicle is in an understeering state; if the second difference is greater than the second threshold value, it is determined that the vehicle is in an oversteering state.

[0018] Through the above technical scheme, when the difference between the front wheel target angle and the current front wheel angle is too large, the present application judges that when the current vehicle is turning, the current front wheel angle value is small, and the vehicle may slide to the outside of the curve, and thus, its steering state is judged to be understeering; when the difference between the current front wheel angle and the front wheel target angle is too large, the present application judges that when the current vehicle is turning, the current front wheel angle of the vehicle is large, and the vehicle cannot follow the desired trajectory, and thus, the steering state of the current vehicle is judged to be oversteering.

[0019] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, after calculating the target braking force corresponding to each wheel of the vehicle according to the current steering wheel angle and the current front wheel angle, it also includes: obtaining the steering intention of the vehicle, and determining the outer wheel of the vehicle and the inner wheel of the vehicle according to the steering intention; based on the steering state, the outer wheel of the vehicle and the inner wheel of the vehicle, judging whether the target braking force corresponding to each wheel meets the preset braking condition; if the target braking force corresponding to each wheel meets the preset braking condition, allowing the electronic mechanical braking system to be driven to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

[0020] Through the above technical solution, after calculating the target braking force corresponding to each wheel, the present application can combine the steering intention of the vehicle, determine whether the target braking force meets the preset braking condition according to the steering state of the vehicle and the inner / outer wheels of the vehicle, and control the target braking force of each wheel according to the real-time state of the vehicle. Therefore, when the vehicle meets the preset braking condition, the present application applies the corresponding target braking force to each wheel, which can effectively avoid the problem of misadjustment.

[0021] In combination with the first aspect and the above-mentioned implementation methods, in some possible implementation methods, the determining whether the target braking force corresponding to each wheel meets the preset braking condition based on the steering state, the outer wheel of the vehicle and the inner wheel of the vehicle includes: if the steering state is an understeering state, then when the target braking force of the outer wheel of the vehicle is greater than the target braking force of the inner wheel of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking condition; if the steering state is an oversteering state, then when the target braking force of the outer wheel of the vehicle is less than the target braking force of the inner wheel of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking condition.

[0022] Through the above technical solution, the present application provides the conditions for judging whether the vehicle needs steering control, and according to the different steering states, combined with the size of the target braking force of the inner / outer wheels of the vehicle, it is judged whether the target braking force of each wheel can successfully complete the steering operation. Therefore, the present application can achieve precise control of each wheel, while satisfying the driver's driving intention, improving the stability of vehicle steering.

[0023] In a second aspect, a steering device is provided, in which the vehicle independently controls each wheel based on an electronic mechanical braking system, and the device includes: an acquisition module, used to acquire the current steering wheel angle, the current front wheel angle and the brake pedal opening of the vehicle; a judgment module, used to judge whether the vehicle meets the preset steering correction conditions according to the current steering wheel angle, the current front wheel angle and the brake pedal opening when the vehicle is in a steering state; and a control module, used to calculate the target braking force corresponding to each wheel of the vehicle according to the current steering wheel angle and the current front wheel angle when the vehicle meets the preset steering correction conditions, and drive the electronic mechanical braking system to apply the corresponding target braking force to each wheel.

[0024] In combination with the second aspect, in certain possible implementations, after determining whether the vehicle satisfies the preset steering correction condition based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, the judgment module is also used to: when the current vehicle does not meet the preset steering correction condition, brake the vehicle according to the braking force corresponding to the brake pedal opening.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the control module is specifically used to: obtain the current speed of the vehicle, and calculate the target yaw angle of the vehicle based on the current speed and the current steering wheel angle; based on the target yaw angle, the current brake pedal opening and the current front wheel angle, search the preset braking force calibration table to obtain the target braking force corresponding to each wheel of the vehicle.

[0026] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the judgment module is specifically used to: calculate the front wheel target angle based on the current steering wheel angle; when the brake pedal opening is greater than the preset opening value, judge whether the vehicle meets the preset steering correction condition based on the difference between the front wheel target angle and the current front wheel angle.

[0027] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the judgment module is also used to: calculate a first difference between the front wheel target angle and the current front wheel angle, and calculate a second difference between the current front wheel angle and the front wheel target angle; when the first difference is greater than a first threshold value, or the second difference is greater than a second threshold value, determine that the vehicle meets the preset steering correction condition.

[0028] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, after calculating the first difference between the front wheel target angle and the current front wheel angle, and calculating the second difference between the current front wheel angle and the front wheel target angle, the judgment module is also used to: when the first difference is greater than the first threshold value, determine that the vehicle is in an understeering state; when the second difference is greater than the second threshold value, determine that the vehicle is in an oversteering state.

[0029] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, after calculating the target braking force corresponding to each wheel of the vehicle based on the current steering wheel angle and the current front wheel angle, the control module is also used to: obtain the steering intention of the vehicle, and determine the outer wheels and the inner wheels of the vehicle based on the steering intention; based on the steering state, the outer wheels of the vehicle and the inner wheels of the vehicle, determine whether the target braking force corresponding to each wheel meets the preset braking conditions; when the target braking force corresponding to each wheel meets the preset braking conditions, allow the electronic mechanical braking system to be driven to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

[0030] In combination with the second aspect and the above-mentioned implementation methods, in some possible implementation methods, the control module is specifically used to determine whether the target braking force corresponding to each wheel meets the preset braking condition based on the steering state, the outer wheel of the vehicle and the inner wheel of the vehicle: when the steering state is an understeering state, the target braking force of the outer wheel of the vehicle is greater than the target braking force of the inner wheel of the vehicle, and determine that the target braking force corresponding to each wheel meets the preset braking condition; when the steering state is an oversteering state, the target braking force of the outer wheel of the vehicle is less than the target braking force of the inner wheel of the vehicle, and determine that the target braking force corresponding to each wheel meets the preset braking condition.

[0031] In a third aspect, a vehicle is provided, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method in the first aspect or any possible implementation of the first aspect.

[0032] In a fourth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the method in the above-mentioned first aspect or any possible implementation manner of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a schematic diagram of a vehicle structure of a specific embodiment of the present application;

[0034] Figure 2 is a flow chart of a steering method provided in an embodiment of the present application;

[0035] Figure 3 is a schematic diagram of signal acquisition of a specific embodiment of the present application;

[0036] Figure 4is a schematic diagram of target yaw calculation according to a specific embodiment of the present application;

[0037] Figure 5 is a schematic diagram of the control logic of a specific embodiment of the present application;

[0038] Figure 6 is a flow chart of a steering method according to a specific embodiment of the present application;

[0039] Figure 7 is a block diagram of a steering device provided in an embodiment of the present application;

[0040] Figure 8 It is a block diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0042] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0043] The development of vehicle braking system has gone through the process from traditional hydraulic vacuum braking, vacuum-assisted hydraulic braking system, electric booster hydraulic braking system, to the current pure electric-controlled electronic mechanical braking system (EMB), that is, wire-controlled braking system. The controller in the electronic mechanical braking system can process electronic signals and control the system actuator to output braking force to complete braking.

[0044] At present, the braking system and steering system of vehicles equipped with wire control brake systems are not integrated, and precise control of each wheel cannot be achieved. During turning, especially when the vehicle is going too fast, if the driver actively brakes, the vehicle will understeer or oversteer. If no intervention is taken, it may even cause safety hazards.

[0045] Therefore, in order to solve the above problems, the present application proposes a steering method, in which the vehicle independently controls each wheel based on an electronic mechanical braking system, and corrects the steering of the vehicle through a wire control brake system, so that the vehicle steers according to the driver's operating expectations, greatly improving the safety of vehicle steering and driving stability.

[0046] Next, the vehicle structure involved in the steering method of the embodiment of the present application will be described. Figure 1 , Figure 1 A schematic diagram of a vehicle structure according to a specific embodiment of the present application.

[0047] Specifically, Figure 1 As shown, the steering method of the embodiment of the present application is implemented based on the electronic mechanical braking system, and the method can realize independent control of four wheels. In the vehicle of the embodiment of the present application, each wheel is equipped with a brake, such as Figure 1 The brake 1, brake 2, brake 3 and brake 4 in the embodiment are used to control each wheel according to the target braking force. For example, brake 1 can control the right front wheel. The electronic mechanical braking system of the embodiment of the present application includes two controllers, namely: a front controller and a rear controller. The front controller is used to control brake 1 and brake 2, and the rear controller is used to control brake 3 and brake 4. Each controller contains two chips, such as Figure 1 Chip 1 and chip 2 in the front controller, and chip 3 and chip 4 in the rear controller, each chip controls a brake, for example, chip 1 controls brake 1 to achieve right front wheel braking. Thus, the present application can output different target braking forces to each wheel by controlling the caliper motor of each wheel.

[0048] In addition, in the embodiment of the present application, the chip integrated control unit main chip MCU (Microcontroller Unit), power chip, pre-drive module, signal acquisition module, variable angle transmission ratio module, and data processing module contained in the front and rear controllers are used to obtain and process vehicle speed, acceleration, steering angle and other data, and judge the vehicle status based on these data to control the operation of the brakes.

[0049] The steering method of an embodiment of the present application is described below with reference to the accompanying drawings. The vehicle of the embodiment of the present application independently controls each wheel based on an electronic mechanical braking system.

[0050] Figure 2 It is a schematic flow chart of a steering method provided in an embodiment of the present application.

[0051] For example, Figure 2 As shown, the steering method includes the following steps:

[0052] In step S201, the current steering wheel angle, current front wheel angle and brake pedal opening of the vehicle are obtained.

[0053] It is understandable that the driver controls the steering of the vehicle by manipulating the steering wheel. Therefore, the present application can monitor the steering wheel angle in real time through sensors to obtain the vehicle's control state. Since the current front wheel angle of the vehicle can reflect the angle at which the driver controls the front wheels to deviate to the left and right sides by manipulating the steering wheel, the present application can determine the vehicle's control state and driving direction based on the current front wheel angle. The present application can obtain the force applied by the driver on the brake pedal based on the obtained brake pedal opening, and transmit the signal to the MCU, thereby adjusting the operation of the braking system.

[0054] In addition, the embodiment of the present application can obtain the actual output front wheel angle signal through the front wheel angle sensor, obtain the brake pedal opening signal in real time through the brake pedal sensor, and transmit the vehicle's current steering wheel angle signal, current front wheel angle signal and brake pedal opening signal to the controller of the electronic mechanical braking system.

[0055] Therefore, the present application can obtain the vehicle's driving status data so that the braking system can accurately respond to the driver's needs and improve the vehicle's steering safety and braking performance.

[0056] In step S202, when the vehicle is in a turning state, it is determined whether the vehicle meets a preset steering correction condition based on the current steering wheel angle, the current front wheel angle and the brake pedal opening.

[0057] It can be understood that the present application obtains data on the current steering wheel angle, the current front wheel angle and the brake pedal opening in step S201. Then, the electronic mechanical braking system controller can judge the driving state of the vehicle by the current steering wheel angle and the current front wheel angle. When the current steering wheel angle is greater than a certain value, the front wheel angle rotates a corresponding angle, and it is determined that the current vehicle is in a turning state.

[0058] Furthermore, the electronic mechanical brake system controller of the embodiment of the present application can determine the current state of the vehicle through the collected relevant signals, that is, whether the steering correction conditions preset in the present application are met.

[0059] Optionally, in some embodiments, after determining whether the vehicle meets the preset steering correction conditions based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, it also includes: if the current vehicle does not meet the preset steering correction conditions, braking the vehicle according to the braking force corresponding to the brake pedal opening.

[0060] Specifically, the present application presets a condition for determining whether a steering correction is required. When the current vehicle does not meet the preset steering correction condition, the vehicle can be braked according to the braking force corresponding to the brake pedal opening obtained in step S201. If the current vehicle meets the preset steering correction condition, the electronic mechanical brake system needs to actively intervene to ensure the safety and stability of the vehicle's steering. The following examples will be listed to specifically introduce the preset steering correction conditions of the present application examples.

[0061] Therefore, the present application determines whether the vehicle meets the preset steering correction conditions before braking each wheel, which can effectively avoid misadjustment of the electronic mechanical braking system and ensure the safety of vehicle steering.

[0062] Optionally, in some embodiments, whether the vehicle meets preset steering correction conditions is determined based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, including: calculating the front wheel target angle based on the current steering wheel angle; when the brake pedal opening is greater than the preset opening value, determining whether the vehicle meets the preset steering correction conditions based on the difference between the front wheel target angle and the current front wheel angle.

[0063] Those skilled in the art can understand that the driver controls the angle of the front wheels to the left and right by manipulating the steering wheel, so as to adjust the direction of the vehicle. Therefore, the present application calculates the target angle of the front wheels according to the current steering wheel angle, and can judge the handling performance and stability of the current vehicle. In addition, the present application needs to judge whether the driver performs a braking operation according to the brake pedal opening, that is, when the currently acquired brake pedal opening is greater than the preset opening value of the embodiment of the present application, the brake signal is transmitted to the MCU.

[0064] Specifically, the present application can obtain the current front wheel angle of the vehicle through the front wheel angle sensor, that is, the actual output front wheel angle, and the electronic mechanical brake system controller receives the steering wheel angle signal, and divides the steering wheel angle by the variable angle transmission ratio to obtain the front wheel target angle, that is, the theoretical front wheel angle. Furthermore, the embodiment of the present application makes a difference between the data of the front wheel target angle and the current front wheel angle, and determines whether the vehicle meets the preset steering correction condition based on the deviation between the two.

[0065] Therefore, the present application takes into account that the target turning angle of the front wheels can reflect the handling performance and stability of the vehicle. When judging whether the current vehicle needs steering correction, the current vehicle is controlled according to the deviation between the theoretical turning angle value and the actual turning angle value to ensure that the vehicle turns and drives according to the driver's expectations.

[0066] Optionally, in some embodiments, whether the vehicle meets the preset steering correction condition is determined based on the difference between the front wheel target angle and the current front wheel angle, including: calculating a first difference between the front wheel target angle and the current front wheel angle, and calculating a second difference between the current front wheel angle and the front wheel target angle; if the first difference is greater than a first threshold value, or the second difference is greater than a second threshold value, it is determined that the vehicle meets the preset steering correction condition.

[0067] It is understandable that during the turning process, the front of the vehicle may fail to enter the expected curve or slide to the outside of the curve, that is, the current steering state is an understeering state; in other cases, the vehicle may slide to the inside of the curve when turning, that is, the current steering state is an oversteering state. Therefore, in order to accurately determine the current steering state of the vehicle, in addition to calculating the difference between the front wheel target angle and the current front wheel angle, the application also calculates the difference between the current front wheel angle and the front wheel target angle to accurately determine different vehicle steering states.

[0068] Specifically, the embodiment of the present application foresees a first threshold value and a second threshold value for the above-mentioned difference, compares the difference between the front wheel target angle and the current front wheel angle with the first threshold value, and compares the difference between the current front wheel angle and the front wheel target angle with the second threshold value, thereby determining whether the vehicle meets the preset steering correction condition, that is, whether active intervention of the electronic mechanical braking system is required. In addition, the present application does not specifically limit the size of the first threshold value and the second threshold value, and those skilled in the art can set them according to actual conditions.

[0069] Optionally, in some embodiments, after calculating the first difference between the front wheel target angle and the current front wheel angle, and calculating the second difference between the current front wheel angle and the front wheel target angle, it also includes: if the first difference is greater than a first threshold value, determining that the vehicle is in an understeering state; if the second difference is greater than a second threshold value, determining that the vehicle is in an oversteering state.

[0070] Specifically, the present application judges that when the difference between the front wheel target angle and the current front wheel angle is too large, the current front wheel angle value, that is, the actual front wheel angle is small when the current vehicle is turning, and the vehicle may slide to the outside of the curve, and thus, its steering state is judged to be an understeering state; the present application judges that when the difference between the current front wheel angle and the front wheel target angle is too large, the current front wheel angle of the vehicle is large when the current vehicle is turning, and the vehicle cannot follow the desired trajectory, and thus, the steering state of the current vehicle is judged to be an oversteering state.

[0071] Based on the above embodiments, the present application can collect the required sensor signals through the electronic mechanical braking system controller, and determine the current state of the vehicle, and determine whether the vehicle has abnormal steering according to the difference between the front wheel target angle and the current front wheel angle, and then correct the steering of the current vehicle through the electronic mechanical braking system.

[0072] In step S203, if the vehicle meets the preset steering correction conditions, the target braking force corresponding to each wheel of the vehicle is calculated according to the current steering wheel angle and the current front wheel angle, and the electronic mechanical braking system is driven to apply the corresponding target braking force to each wheel.

[0073] Specifically, after determining that the current vehicle meets the preset steering correction conditions, the present application needs to use the electronic mechanical brake system controller to process the acquired vehicle driving state parameters, thereby calculating the target braking force of each wheel, and finally driving the electronic mechanical brake system to control the four-wheel brakes to output the target braking force to control the wheel speeds of the inner and outer wheels to achieve vehicle steering correction. The following examples will specifically introduce the vehicle steering correction strategy of the present application.

[0074] It should be noted that when the embodiment of the present application drives the electronic mechanical brake system to apply the corresponding target braking force to each wheel, the target braking force is applied to the corresponding wheel by controlling the caliper motor corresponding to each wheel respectively.

[0075] Optionally, in some embodiments, the target braking force corresponding to each wheel of the vehicle is calculated based on the current steering wheel angle and the current front wheel angle, including: obtaining the current speed of the vehicle, and calculating the target yaw angle of the vehicle based on the current speed and the current steering wheel angle; based on the target yaw angle, the current brake pedal opening and the current front wheel angle, searching a preset braking force calibration table to obtain the target braking force corresponding to each wheel of the vehicle.

[0076] It can be understood that the target yaw angle of the vehicle is an important parameter for the driver to control the driving direction and path of the vehicle during driving, which is related to the driver's adjustment of the steering and brake pedals of the wheels. Therefore, this application calculates the target yaw angle of the vehicle based on the current vehicle speed and the current steering wheel angle.

[0077] Specifically, various sensors are installed in the vehicle of the embodiment of the present application, such as a brake pedal sensor, a steering wheel angle sensor, etc. The electronic mechanical brake system controller can collect signals obtained by each sensor, such as Figure 3 As shown, Figure 3This is a schematic diagram of signal acquisition for a specific embodiment of the present application. The electronic mechanical brake system controller will collect and process longitudinal acceleration signals, lateral acceleration signals, yaw rate signals, brake pedal signals, wheel speed signals, gear signals and front wheel angle signals, and calculate the target yaw rate based on the steering wheel angle and vehicle speed.

[0078] It should be noted that Figure 4 FIG. 1 is a schematic diagram of target yaw calculation of a specific embodiment of the present application. The target yaw angle of the embodiment of the present application can be calculated based on a single track model, such as Figure 4 As shown, the embodiment of the present application obtains the desired yaw based on the Ackermann equation according to the steering wheel angle, combines the vehicle speed, increases the yaw rate limit according to the current motion state of the vehicle, and needs to correct the target yaw angle according to the driver's operating state. After filtering, in order to increase the robustness of the system, the calculated value is compensated accordingly, and finally the driver's desired target yaw angle is output. Furthermore, the electronic mechanical brake system controller of the embodiment of the present application calculates the target braking force of each wheel according to the target yaw angle and the collected signal and outputs a request signal.

[0079] Furthermore, the present application takes into account that the yaw angle can determine the braking force of the left and right wheels. Therefore, the target braking force corresponding to each wheel is pre-calibrated according to the target yaw angle, and the actual braking force is corrected in combination with the vehicle speed and the front wheel turning angle to obtain a more accurate target braking force.

[0080] During the actual execution process, after the electronic mechanical braking system controller recognizes the braking force corresponding to the brake pedal opening, the electronic mechanical braking system actively intervenes, automatically compensates for the braking force, calculates the target yaw angle, obtains the target braking force by looking up the table, and corrects the braking force through real-time feedback of the vehicle speed signal, ultimately achieving precise control of each wheel.

[0081] Furthermore, in some embodiments, after calculating the target braking force corresponding to each wheel of the vehicle based on the current steering wheel angle and the current front wheel angle, it also includes: obtaining the steering intention of the vehicle, and determining the outer wheels and the inner wheels of the vehicle based on the steering intention; based on the steering state, the outer wheels of the vehicle and the inner wheels of the vehicle, judging whether the target braking force corresponding to each wheel meets the preset braking conditions; if the target braking force corresponding to each wheel meets the preset braking conditions, allowing the driving electronic mechanical braking system to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

[0082] Among them, the vehicle's turning intention refers to the driver's need to turn or change the direction of travel while driving, which can be judged based on the driver's operations such as turning the steering wheel, stepping on the accelerator, braking, changing lanes, etc.

[0083] It can be understood that when the vehicle is turning, the tire on the same side as the steering wheel turning direction is the vehicle's inner wheel, and the tire on the opposite side from the steering wheel turning direction is the vehicle's outer wheel. Therefore, the present application can distinguish between the vehicle's outer wheels and the vehicle's inner wheels based on the vehicle's steering intention, that is, the direction in which the driver controls the steering wheel to turn.

[0084] Specifically, the present application obtains the steering wheel angle signal through the electronic mechanical braking system controller to obtain the vehicle's steering intention, and determines whether the vehicle needs intervention of the steering control strategy in combination with the steering state and the vehicle's outer wheels and inner wheels. When the vehicle meets the preset braking conditions, the electronic mechanical braking system controls the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel, so that the current steering action meets the driver's wishes and driving mode requirements. In this way, the vehicle's misadjustment can be effectively avoided and precise control of the vehicle's steering can be achieved.

[0085] Optionally, in some embodiments, based on the steering state, the outer wheels of the vehicle and the inner wheels of the vehicle, it is determined whether the target braking force corresponding to each wheel meets the preset braking conditions, including: if the steering state is an understeering state, then when the target braking force of the outer wheels of the vehicle is greater than the target braking force of the inner wheels of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking conditions; if the steering state is an oversteering state, then when the target braking force of the outer wheels of the vehicle is less than the target braking force of the inner wheels of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking conditions.

[0086] In some cases, the steering state of the vehicle is an understeering state. If the target braking force of the outer wheels of the vehicle is greater than the target braking force of the inner wheels of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking conditions. At this time, it is necessary to increase the braking force of the inner wheels of the vehicle to ensure that the vehicle passes the turn smoothly; in other cases, the steering state of the vehicle is an oversteering state. If the target braking force of the outer wheels of the vehicle is less than the target braking force of the inner wheels of the vehicle, it is determined that the target braking force corresponding to each wheel meets the preset braking conditions. At this time, it is necessary to increase the target braking force of the outer wheels of the vehicle to prevent the vehicle from skidding due to excessive speed during the turning process.

[0087] Therefore, in this application, when the vehicle turns and the driver steps on the brake pedal due to excessive speed, the electronic mechanical braking system intervenes and collects corresponding signals, judges the vehicle's usage status through the collected sensor signals, obtains the driver's control expectations based on the driver's steering wheel angle input, and judges whether the vehicle meets the preset braking conditions based on the difference between the target front wheel angle and the current front wheel angle. If the preset braking conditions are not met, the braking force is output normally according to the driver's needs. If the preset braking conditions are met, the electronic mechanical braking system controls the wheel speeds on both sides through the braking force to complete the driver's desired steering.

[0088] Based on the above embodiments, the present application can control the vehicle according to the vehicle steering correction strategy, effectively avoiding the vehicle steering and the problem of understeering or oversteering of the vehicle after the driver actively brakes due to excessive speed. In order to enable those skilled in the art to further understand the implementation of the steering method of the present application, the following embodiments are listed to schematically illustrate the control logic of the method.

[0089] Specifically, Figure 5 This is a schematic diagram of the control logic of a specific embodiment of the present application.

[0090] It should be noted that, as described in the above embodiments, in order to implement the steering method of the present application, Figure 5 As shown, in the electronic mechanical braking system of the embodiment of the present application, the structure of the control main chip needs to include but is not limited to the following modules: a variable angle transmission ratio module, a signal acquisition module, a data processing module, a control unit main chip and a pre-drive module.

[0091] Among them, the input of the variable angle transmission ratio module is the steering wheel angle signal. The embodiment of the present application uses the steering wheel angle divided by the variable angle transmission ratio to obtain the target front wheel angle; the signal acquisition module is used to collect sensor signals, including longitudinal acceleration signals, lateral acceleration signals, yaw angular velocity signals, brake pedal signals, wheel speed signals, gear signals and current front wheel angle signals, and calculates the target yaw angle based on the steering wheel angle and vehicle speed.

[0092] Optionally, the data processing module is used to collect the signal from the signal acquisition module and the target front wheel angle obtained by the variable angle transmission ratio module, and compare the target front wheel angle and the current front wheel angle deviation with a threshold value (the threshold is a set value). If the deviation exceeds the threshold, the electronic mechanical braking system needs to actively intervene. The data processing module calculates the target braking torque of the wheel based on the target yaw angle and the collected signal and outputs a request signal.

[0093] Optionally, the control unit main chip is used to receive request signals and related signals from the data processing module and send instructions; the pre-drive module is used to output target braking force signals to the wheel brakes, and the wheel brakes apply braking force to the wheels to control the speed of the inner and outer wheels.

[0094] Therefore, the present application can realize a vehicle control method for independently controlling the four-wheel braking force. During the vehicle steering process, the vehicle steering is corrected through the electronic mechanical braking system so that the vehicle steers according to the driver's operating expectations.

[0095] Furthermore, the following examples are given to illustrate the process of the steering method of the present application. Figure 6 This is a flow chart of a steering method according to a specific embodiment of the present application. Figure 6 As shown, the method comprises the following steps:

[0096] Step S601: the driver steps on the brake pedal to perform a vehicle steering operation, and the electronic mechanical brake system begins to intervene;

[0097] Step S602, the electronic mechanical brake system controller collects required sensor signals to determine the vehicle status;

[0098] Step S603, confirming that the vehicle's steering is abnormal and that the electronic mechanical braking system is required to perform steering correction;

[0099] Step S604, the electronic mechanical brake system controller processes the signal data to obtain the target braking force of the four wheels;

[0100] Step S605, controlling the four-wheel brakes to output target braking forces to control the wheel speeds of the inner and outer wheels to correct the vehicle steering.

[0101] Therefore, the present application judges the steering state of the vehicle, corrects the steering of the vehicle when the current vehicle has steering abnormalities, calculates the target braking force of each wheel, achieves precise control of the four wheels, and improves the safety of vehicle steering and driving stability.

[0102] In summary, the steering method of the present application obtains the vehicle's current steering wheel angle, current front wheel angle and brake pedal opening, and when the vehicle is in a steering state, determines whether the vehicle meets the preset steering correction conditions based on the current steering wheel angle, current front wheel angle and brake pedal opening; when the vehicle meets the preset steering correction conditions, calculates the target braking force corresponding to each wheel of the vehicle based on the current steering wheel angle and the current front wheel angle, and drives the electronic mechanical braking system to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

[0103] Therefore, the present application can effectively avoid the problem that the vehicle understeers or oversteers, or even causes safety hazards, when the vehicle speed is too fast and the driver actively steps on the brakes during the turning process. It realizes the independent control method of the four-wheel braking force, so that the vehicle can steer according to the driver's operating expectations, greatly improving the safety of vehicle steering and driving stability.

[0104] Figure 7 It is a structural schematic diagram of a steering device of a vehicle provided in an embodiment of the present application.

[0105] For example, Figure 7 As shown, the steering device 10 of the vehicle may include: an acquisition module 100 , a judgment module 200 and a control module 300 .

[0106] Among them, the acquisition module 100 is used to obtain the current steering wheel angle, the current front wheel angle and the brake pedal opening of the vehicle; the judgment module 200 is used to judge whether the vehicle meets the preset steering correction conditions according to the current steering wheel angle, the current front wheel angle and the brake pedal opening when the vehicle is in a steering state; the control module 300 is used to calculate the target braking force corresponding to each wheel of the vehicle according to the current steering wheel angle and the current front wheel angle when the vehicle meets the preset steering correction conditions, and drive the electronic mechanical braking system to apply the corresponding target braking force to each wheel.

[0107] Optionally, in some embodiments, after determining whether the vehicle meets the preset steering correction conditions based on the current steering wheel angle, the current front wheel angle and the brake pedal opening, the judgment module 200 is also used to: when the current vehicle does not meet the preset steering correction conditions, brake the vehicle with corresponding braking force according to the brake pedal opening.

[0108] Optionally, in some embodiments, the control module 300 is specifically used to: obtain the current speed of the vehicle, and calculate the target yaw angle of the vehicle based on the current speed and the current steering wheel angle; based on the target yaw angle, the current brake pedal opening and the current front wheel angle, search a preset braking force calibration table to obtain the target braking force corresponding to each wheel of the vehicle.

[0109] Optionally, in some embodiments, the judgment module 200 is specifically used to: calculate the front wheel target angle based on the current steering wheel angle; when the brake pedal opening is greater than a preset opening value, judge whether the vehicle meets the preset steering correction condition based on the difference between the front wheel target angle and the current front wheel angle.

[0110] Optionally, in some embodiments, the judgment module 200 is also used to: calculate a first difference between the front wheel target angle and the current front wheel angle, and calculate a second difference between the current front wheel angle and the front wheel target angle; when the first difference is greater than a first threshold value, or the second difference is greater than a second threshold value, determine that the vehicle meets a preset steering correction condition.

[0111] Optionally, in some embodiments, after calculating a first difference between the front wheel target angle and the current front wheel angle, and calculating a second difference between the current front wheel angle and the front wheel target angle, the judgment module 200 is further used to: determine that the vehicle is in an understeering state when the first difference is greater than a first threshold value; and determine that the vehicle is in an oversteering state when the second difference is greater than a second threshold value.

[0112] Optionally, in some embodiments, after calculating the target braking force corresponding to each wheel of the vehicle based on the current steering wheel angle and the current front wheel angle, the control module 300 is further used to: obtain the steering intention of the vehicle, and determine the outer wheels and the inner wheels of the vehicle based on the steering intention; based on the steering state, the outer wheels of the vehicle and the inner wheels of the vehicle, determine whether the target braking force corresponding to each wheel meets the preset braking conditions; when the target braking force corresponding to each wheel meets the preset braking conditions, allow the driving electronic mechanical braking system to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

[0113] Optionally, in some embodiments, based on the steering state, the outer wheels of the vehicle and the inner wheels of the vehicle, it is determined whether the target braking force corresponding to each wheel meets the preset braking conditions. The control module 300 is specifically used to: when the steering state is an understeering state, when the target braking force of the outer wheels of the vehicle is greater than the target braking force of the inner wheels of the vehicle, determine that the target braking force corresponding to each wheel meets the preset braking conditions; when the steering state is an oversteering state, when the target braking force of the outer wheels of the vehicle is less than the target braking force of the inner wheels of the vehicle, determine that the target braking force corresponding to each wheel meets the preset braking conditions.

[0114] It should be noted that the above explanation of the steering method embodiment is also applicable to the steering device of this embodiment, and will not be repeated here.

[0115] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0116] It should be understood that the steering device provided in this embodiment is used to execute the above-mentioned steering method, and thus can achieve the same effect as the above-mentioned implementation method, which will not be described in detail here.

[0117] The embodiment of the present application also provides a vehicle, Figure 8 is a schematic diagram of the structure of a vehicle provided in an embodiment of the present application, such as Figure 8 As shown, the vehicle may include: a memory 801 , a processor 802 , and a computer program stored in the memory 801 and executable on the processor 802 .

[0118] When the processor 802 executes the program, the steering method provided in the above embodiment is implemented.

[0119] Furthermore, the vehicle also includes:

[0120] The communication interface 803 is used for communication between the memory 801 and the processor 802 .

[0121] The memory 801 is used to store computer programs that can be executed on the processor 802 .

[0122] The memory 801 may include a high-speed RAM (Random Access Memory) memory, and may also include a non-volatile memory, such as at least one disk memory.

[0123] If the memory 801, the processor 802 and the communication interface 803 are implemented independently, the communication interface 803, the memory 801 and the processor 802 can be connected to each other through a bus and communicate with each other. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 8 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0124] Optionally, in a specific implementation, if the memory 801, the processor 802 and the communication interface 803 are integrated on a chip, the memory 801, the processor 802 and the communication interface 803 can communicate with each other through an internal interface.

[0125] The processor 802 may be a CPU (Central Processing Unit), or an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of the present application.

[0126] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is executed on a computer, the computer executes the above-mentioned related method steps to implement the steering method provided in the above-mentioned embodiment.

[0127] The computer-readable storage medium provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, which will not be repeated here.

[0128] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A steering method, characterized in that: The vehicle independently controls each wheel based on an electromechanical braking system, which includes the following steps: Obtaining the current steering wheel angle, current front wheel angle and brake pedal opening of the vehicle; When the vehicle is in a steering state, judging whether the vehicle satisfies a preset steering correction condition according to the current steering wheel angle, the current front wheel angle and the brake pedal opening; and If the vehicle meets the preset steering correction condition, the target braking force corresponding to each wheel of the vehicle is calculated according to the current steering wheel angle and the current front wheel angle, and the electronic mechanical braking system is driven to apply the corresponding target braking force to each wheel.

2. The method according to claim 1, characterized in that After judging whether the vehicle satisfies the preset steering correction condition according to the current steering wheel angle, the current front wheel angle and the brake pedal opening, the method further includes: If the current vehicle does not meet the preset steering correction condition, the vehicle is braked according to the braking force corresponding to the brake pedal opening.

3. The method according to claim 1, characterized in that The calculating the target braking force corresponding to each wheel of the vehicle according to the current steering wheel angle and the current front wheel angle includes: Acquiring a current vehicle speed of the vehicle, and calculating a target yaw angle of the vehicle according to the current vehicle speed and the current steering wheel angle; Based on the target yaw angle, the current brake pedal opening and the current front wheel turning angle, a preset braking force calibration table is searched to obtain a target braking force corresponding to each wheel of the vehicle.

4. The method according to any one of claims 1 to 3, characterized in that The determining whether the vehicle satisfies a preset steering correction condition according to the current steering wheel angle, the current front wheel angle and the brake pedal opening includes: Calculating a front wheel target angle according to the current steering wheel angle; When the brake pedal opening is greater than the preset opening value, it is determined whether the vehicle satisfies a preset steering correction condition according to a difference between the front wheel target turning angle and the current front wheel turning angle.

5. The method according to claim 4, characterized in that The determining whether the vehicle satisfies a preset steering correction condition according to the difference between the front wheel target turning angle and the current front wheel turning angle comprises: Calculating a first difference between the front wheel target turning angle and the current front wheel turning angle, and calculating a second difference between the current front wheel turning angle and the front wheel target turning angle; If the first difference is greater than a first threshold value, or the second difference is greater than a second threshold value, it is determined that the vehicle meets the preset steering correction condition.

6. The method according to claim 5, characterized in that After calculating a first difference between the front wheel target turning angle and the current front wheel turning angle, and calculating a second difference between the current front wheel turning angle and the front wheel target turning angle, the method further includes: If the first difference is greater than the first threshold value, it is determined that the vehicle is in an understeering state; If the second difference is greater than the second threshold value, it is determined that the vehicle is in an oversteering state.

7. The method according to claim 6, characterized in that After calculating the target braking force corresponding to each wheel of the vehicle according to the current steering wheel angle and the current front wheel angle, the method further includes: Acquiring a steering intention of the vehicle, and determining an outer wheel of the vehicle and an inner wheel of the vehicle according to the steering intention; Based on the steering state, the outer wheel of the vehicle and the inner wheel of the vehicle, determining whether the target braking force corresponding to each wheel meets a preset braking condition; If the target braking force corresponding to each wheel meets the preset braking condition, the electronic mechanical braking system is allowed to be driven to control the caliper motor corresponding to each wheel to apply the corresponding target braking force to each wheel.

8. The method according to claim 6, characterized in that The determining, based on the steering state, the outer wheel of the vehicle and the inner wheel of the vehicle, whether the target braking force corresponding to each wheel meets a preset braking condition includes: If the steering state is an understeering state, determining that the target braking force corresponding to each wheel meets the preset braking condition when the target braking force of the outer wheel of the vehicle is greater than the target braking force of the inner wheel of the vehicle; If the steering state is an oversteering state, it is determined that the target braking force corresponding to each wheel meets the preset braking condition when the target braking force of the outer wheel of the vehicle is less than the target braking force of the inner wheel of the vehicle.

9. A vehicle, characterized in that: The vehicle comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steering method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the steering method according to any one of claims 1 to 8 is implemented.

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