Steering state judgment and torque control method and device and vehicle controller

Abstract

The application discloses a steering state judgment and torque control method and device, and a whole vehicle controller, and the steering state judgment and torque control method comprises the following steps: acquiring an ideal yaw angular velocity and an actual yaw angular velocity of the vehicle; determining that the vehicle is in an over-reverse state according to an angular velocity condition of the vehicle, wherein the angular velocity condition comprises that an absolute value of a yaw angular velocity difference value is greater than a set threshold value, and a product of the ideal yaw angular velocity and the actual yaw angular velocity is less than zero; the yaw angular velocity difference value is equal to the ideal yaw angular velocity minus the actual yaw angular velocity. By comparing the size and direction (positive / negative) of the actual yaw angular velocity and the ideal yaw angular velocity, the state of reverse steering of the vehicle in the driving process is identified, so that whether the over-reverse state of the vehicle occurs can be accurately identified.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, and more particularly to a steering state judgment and torque control method and device and a vehicle controller. BACKGROUND

[0002] At present, for independent four-wheel drive vehicles, the difference between the actual yaw rate and the ideal yaw rate is mainly used to judge the steering characteristics of the vehicle. However, in the current steering control state recognition process, whether the vehicle appears understeering or oversteering in normal left turning and normal right turning is mainly recognized, but the state recognition method cannot accurately judge some working conditions of the vehicle. SUMMARY

[0003] The present application is proposed to solve at least one of the above problems.

[0004] According to a first aspect of the present application, a steering state judgment and torque control method is provided, which comprises: obtaining an ideal yaw rate and an actual yaw rate of a vehicle; determining that the vehicle is in an over-reverse state when the vehicle meets an angular velocity condition, wherein the angular velocity condition comprises: an absolute value of a yaw rate difference is greater than a set threshold, and a product of the ideal yaw rate and the actual yaw rate is less than or equal to zero; the yaw rate difference is equal to the ideal yaw rate minus the actual yaw rate.

[0005] In an embodiment of the present application, when the vehicle is in the over-reverse state, if the ideal yaw rate and the actual yaw rate meet a first judgment condition, it is determined that the vehicle is in a reverse recovery state; wherein the first judgment condition comprises: the ideal yaw rate, the actual yaw rate, and the yaw rate difference are all greater than or equal to zero; or, the ideal yaw rate, the actual yaw rate, and the yaw rate difference are all less than zero (A6).

[0006] In an embodiment of the present application, when the vehicle is in the reverse recovery state, if the ideal yaw rate and the actual yaw rate meet a second judgment condition, it is determined that the vehicle is in an oversteering state; wherein the second judgment condition comprises: the ideal yaw rate and the actual yaw rate are both greater than or equal to zero, and the yaw rate difference is less than zero; or, the ideal yaw rate and the actual yaw rate are both less than zero, and the yaw rate difference is greater than or equal to zero (A7).

[0007] In an embodiment of the present application, when the vehicle is in the anti-slap recovery state, if the ideal yaw rate and the actual yaw rate satisfy a third judgment condition, it is determined that the vehicle is in a first transition state; wherein the third judgment condition comprises: the absolute value of the yaw rate difference is less than or equal to the set threshold value (A17).

[0008] In an embodiment of the present application, when the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy a fourth judgment condition, it is determined that the vehicle is in a neutral steering state; wherein the fourth judgment condition comprises: the ideal yaw rate and the actual yaw rate satisfy the third judgment condition for a duration exceeding a first time threshold value (A9).

[0009] In an embodiment of the present application, when the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy a fifth judgment condition, it is determined that the vehicle is in the over-steering state; wherein the fifth judgment condition comprises: the ideal yaw rate and the actual yaw rate satisfy the third judgment condition for a duration not exceeding a first time threshold value (A11).

[0010] In an embodiment of the present application, when the vehicle is in the anti-slap recovery state, if the anti-slap recovery state is continuously maintained for a time greater than a third time threshold value, it is determined that the vehicle is in a neutral steering state (A16).

[0011] In an embodiment of the present application, when the vehicle is in the over-anti-slap state, if the ideal yaw rate and the actual yaw rate satisfy a sixth judgment condition, it is determined that the vehicle is in an over-steering state; wherein the sixth judgment condition comprises: the ideal yaw rate and the actual yaw rate are both greater than or equal to zero, and the yaw rate difference is less than zero; or, the ideal yaw rate and the actual yaw rate are both less than zero, and the yaw rate difference is greater than or equal to zero (A18).

[0012] In an embodiment of the present application, the steering state judgment and torque control method further comprises: determining whether the vehicle satisfies the angle rate condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate.

[0013] In an embodiment of the present application, the determining whether the vehicle satisfies the angular velocity condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate comprises: when the vehicle is currently in the over-steering state or the under-steering state, if the ideal yaw rate and the actual yaw rate satisfy a first sub-angular velocity condition in the angular velocity condition, it is determined that the vehicle satisfies the angular velocity condition; wherein the first sub-angular velocity condition comprises: the actual yaw rate is less than zero, and both the ideal yaw rate and the yaw rate difference are greater than or equal to zero; or, the actual yaw rate is greater than zero, and both the ideal yaw rate and the yaw rate difference are less than or equal to zero (A15).

[0014] In an embodiment of the present application, the determining whether the vehicle satisfies the angular velocity condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate comprises: when the vehicle is currently in the neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy a second sub-angular velocity condition in the angular velocity condition, it is determined that the vehicle satisfies the angular velocity condition; wherein the second sub-angular velocity condition comprises: the actual yaw rate is less than zero, both the ideal yaw rate and the yaw rate difference are greater than or equal to zero, and the absolute value of the yaw rate difference is greater than the set threshold; or, the actual yaw rate is greater than zero, and both the ideal yaw rate and the yaw rate difference are less than or equal to zero, and the absolute value of the yaw rate difference is greater than the set threshold (A12).

[0015] In an embodiment of the present application, the steering state judgment and torque control method further comprises: when the vehicle is in the over-rebound state, the rebound recovery state, the over-steering state or the first transition state, distributing torque to each drive wheel of the vehicle according to an over-steering strategy.

[0016] In an embodiment of the present application, the distributing torque to each drive wheel of the vehicle according to the over-steering strategy comprises: in the case that the total torque of the vehicle is unchanged, shifting torque to the front drive wheel of the vehicle while shifting torque to the drive wheel on the side opposite to the direction of the ideal yaw rate.

[0017] In one embodiment of the present application, the torque is transferred to the driving wheel on the side opposite to the direction of the ideal yaw rate while the torque is transferred to the front driving wheel of the vehicle without changing the total torque of the vehicle, which includes: increasing the torque of the front driving wheel of the vehicle and reducing the torque of the rear driving wheel of the vehicle without changing the total torque of the vehicle; and increasing the torque of the driving wheel on the side opposite to the direction of the ideal yaw rate and reducing the torque of the driving wheel on the same side of the ideal yaw rate based on the distribution result of increasing the torque of the front driving wheel of the vehicle and reducing the torque of the rear driving wheel of the vehicle without changing the total torque of the vehicle.

[0018] According to the second aspect of the present application, a steering state judgment and torque control device is also provided, which includes a storage medium and a processor, the storage medium stores a computer program which is run by the processor, and the computer program, when being run by the processor, causes the processor to execute any one of the above-mentioned steering state judgment and torque control methods.

[0019] According to the third aspect of the present application, a vehicle control unit is also provided, which includes any one of the above-mentioned steering state judgment and torque control devices.

[0020] According to the fourth aspect of the present application, a vehicle is also provided, which includes a vehicle body and any one of the above-mentioned vehicle control units arranged on the vehicle body.

[0021] In one embodiment of the present application, the vehicle is an independent four-wheel drive vehicle.

[0022] The steering state judgment and torque control method and device, and the vehicle control unit provided by the embodiments of the present application determine that the vehicle is in the over-steering state when the absolute value of the yaw rate difference is greater than the set threshold value and the product of the ideal yaw rate and the actual yaw rate is less than zero. Compared with the existing state recognition method of identifying whether the vehicle is in the over-steering or under-steering state, the present application compares the size and direction (positive / negative) of the actual yaw rate and the ideal yaw rate, and identifies the state of the vehicle in the process of steering the steering wheel in the opposite direction, so as to accurately identify whether the vehicle is in the over-steering state, identify the risk of instability of the vehicle in time, facilitate the instability control of the vehicle in time, and improve the stability of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments description. Obviously, the drawings in the following description only some of the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor.

[0024] Figure 1 Flow chart of the steering state judgment and torque control method according to an embodiment of the present application;

[0025] Figure 2 Flow chart of the steering state judgment and torque control method according to another embodiment of the present application;

[0026] Figure 3 Schematic block diagram of the switching between different states in the steering state judgment and torque control process according to an embodiment of the present application;

[0027] Figure 4 Schematic block diagram of the steering state judgment and torque control device according to an embodiment of the present application;

[0028] Figure 5 Schematic block diagram of the vehicle controller according to an embodiment of the present application;

[0029] Figure 6 Schematic block diagram of the vehicle according to an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the objects, technical solutions and advantages of the present application more obvious, the following will describe the example embodiments according to the present application in detail with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein. Based on the embodiments of the present application described in the present application, all other embodiments obtained by those skilled in the art without creative labor should fall within the protection scope of the present application.

[0031] In the following description, a large number of specific details are given in order to provide a more thorough understanding of the present application. However, it is obvious for those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid obscuring the present application, some technical features known in the art are not described.

[0032] It should be understood that the present application can be implemented in different forms, and should not be interpreted as limited to the embodiments presented herein. On the contrary, the embodiments are provided to make the disclosure complete and full, and to fully convey the scope of the present application to those skilled in the art.

[0033] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0034] For a thorough understanding of the present application, reference will be made to the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0035] Some embodiments of the present application will now be described in detail in connection with the annexed drawings. Where possible, like features are denoted with like reference numerals. Where appropriate, features of one embodiment can be applied to another embodiment.

[0036] First, the application scenario of the steering state judgment and torque control method exemplified by the present application is introduced, which can be applied to the steering control process of the vehicle.

[0037] With reference to Figure 1 and Figure 2 , the present application provides a steering state judgment and torque control method, which includes:

[0038] Obtaining an ideal yaw rate and an actual yaw rate of the vehicle;

[0039] When the vehicle meets an angular velocity condition, determining that the vehicle is in an over-steer state, wherein the angular velocity condition includes: an absolute value of a yaw rate difference is greater than a set threshold, and a product of the ideal yaw rate and the actual yaw rate is less than zero; the yaw rate difference is equal to the ideal yaw rate minus the actual yaw rate.

[0040] In the above scheme, the vehicle is determined to be in the over-steering state when the absolute value of the yaw rate difference is greater than a set threshold, and the product of the ideal yaw rate and the actual yaw rate is less than zero. Compared with the existing state recognition method for identifying whether the vehicle is in the over-steering or under-steering state, the present application compares the size and direction (positive / negative) of the actual yaw rate and the ideal yaw rate to identify the state of the vehicle in the process of steering back, so as to accurately identify whether the vehicle is in the over-steering state, identify the risk of instability of the vehicle in time, control the instability of the vehicle in time, and improve the stability of the vehicle. The above steps will be described in detail below with reference to the accompanying drawings.

[0041] First of all, it needs to be explained that the neutral steering state refers to: when the absolute value of the yaw rate difference is less than or equal to the set threshold, the neutral steering state is maintained. When the conditions are not met, the vehicle can return to the neutral steering state after a certain time delay after entering other states. The ideal yaw rate has a correlation with the steering wheel angle (SWA), and the ideal yaw rate is consistent with the direction of the steering wheel angle. For example, the left turn can be defined as the positive direction of the angular velocity, and the right turn can be defined as the negative direction of the angular velocity, so that the ideal yaw rate and the steering wheel angle have the same sign. Of course, the definition of the positive direction and the negative direction can also be in the opposite way.

[0042] It needs to be explained that: as Figure 3 Delay1 in the above formula refers to the first transition state, which represents that the vehicle is restored from over-steering to neutral steering, not directly switched, but first switched from over-steering to the first transition state, and then decided to switch to the neutral steering state or return to the over-steering state according to whether the related conditions are met in the first transition state. Figure 3 Delay2 in the above formula refers to the second transition state, which represents that the vehicle is restored from under-steering to neutral steering, not directly switched, but first switched from under-steering to the second transition state, and then decided to switch to the neutral steering state or return to the under-steering state according to whether the related conditions are met in the second transition state.

[0043] In the above formula, the under-steering state refers to: the actual yaw rate and the ideal yaw rate are in the same direction, the absolute value of the ideal yaw rate is greater than the absolute value of the actual yaw rate, and the absolute value of the yaw rate difference is greater than the set threshold. The over-steering state refers to: the actual yaw rate and the ideal yaw rate are in the same direction, the absolute value of the ideal yaw rate is less than the absolute value of the actual yaw rate, and the absolute value of the yaw rate difference is greater than the set threshold. The above formula and Figure 2 and Figure 3 will be described in detail below.

[0044] Reference Figure 1 After the ideal yaw rate and the actual yaw rate of the vehicle are obtained, it is determined whether the vehicle is in the oversteer state according to a yaw rate condition of the vehicle. Specifically, when the vehicle satisfies the yaw rate condition, it is determined that the vehicle is in the oversteer state. The yaw rate condition includes: an absolute value of the yaw rate difference is greater than a set threshold, and a product of the ideal yaw rate and the actual yaw rate is less than zero; the yaw rate difference is equal to the ideal yaw rate minus the actual yaw rate. If the ideal yaw rate and the actual yaw rate of the vehicle satisfy the yaw rate condition, it is determined that the vehicle is in the oversteer state.

[0045] When the absolute value of the yaw rate difference of the vehicle is greater than the set threshold, it indicates that the difference between the current yaw rate and the actual yaw rate of the vehicle is large, and has reached the preset set threshold range. When the product of the ideal yaw rate and the actual yaw rate is less than zero, it indicates that the ideal yaw rate or / and the actual yaw rate has a large mutation, and the mutation changes the positive and negative signs of the ideal yaw rate or the actual yaw rate and changes the direction, i.e., the direction has changed from left turn to right turn, or from right turn to left turn, resulting in that the signs (turning directions) of the ideal yaw rate and the actual yaw rate are completely different.

[0046] The mutation mode can include at least the following cases: 1. Due to the rapid rotation of the steering wheel by the driver, the direction of the ideal yaw rate has changed from left turn to right turn, or from right turn to left turn, while the actual yaw rate basically remains unchanged or changes little, so that the actual yaw rate cannot keep up with the change of the ideal yaw rate; 2. Due to the slip of the front wheels or / and the rear wheels of the vehicle, the actual yaw rate of the vehicle has a large mutation, and the direction has changed from left turn to right turn, or from right turn to left turn, while the ideal yaw rate basically remains unchanged or changes little under the condition that the driver basically does not move the steering wheel, so that the ideal yaw rate cannot keep up with the change of the actual yaw rate; 3. Both the ideal yaw rate and the actual yaw rate have mutations, but the directions of the mutations are opposite, for example, the direction of the ideal yaw rate mutates to the right while the direction of the actual yaw rate mutates to the left; or, the direction of the ideal yaw rate mutates to the left while the direction of the actual yaw rate mutates to the right.

[0047] The embodiment of the present application identifies the state when the absolute value of the yaw rate difference is greater than the set threshold value and the product of the ideal yaw rate and the actual yaw rate is less than zero as neither over-steering nor under-steering, but as an over-reversing state. Compared with the prior art which does not identify the state, the embodiment of the present application identifies the state of reversing the steering wheel of the vehicle during driving by comparing the size and direction (positive / negative) of the actual yaw rate and the ideal yaw rate, so as to accurately identify whether the vehicle appears in the over-reversing state, thereby facilitating subsequent adjustment of the torque control strategy for the over-reversing state to inhibit the vehicle from continuing to develop in the direction of instability, so that compared with the prior art, the vehicle can be identified to possibly be in the state of instability earlier, thereby facilitating timely and effective torque control to prevent the vehicle from further instability. In a more preferred embodiment, when certain conditions are met, the vehicle can be gradually adjusted from the over-reversing state to the neutral steering stable state.

[0048] According to the rotation operation of the driver on the steering wheel, the change of the road adhesion coefficient between the road and the wheel, or the effect of the torque adjustment, the vehicle can gradually exit from the over-reversing state and enter other states. The exiting mode is related to the mode and timing of the effect of the rotation operation of the driver on the steering wheel, the change of the road adhesion coefficient between the road and the wheel, or the torque adjustment. Several modes of exiting the over-reversing state are exemplarily introduced below.

[0049] Exemplarily, referring to Figure 2 and Figure 3 When the vehicle is in the over-reversing state, if the ideal yaw rate and the actual yaw rate satisfy the first judgment condition, it is determined that the vehicle is in the reverse recovery state, and the vehicle is switched from the over-reversing state to the reverse recovery state. Exemplarily, the torque can be distributed to each driving wheel of the vehicle according to the torque control strategy such as but not limited to the over-steering strategy. The first judgment condition includes: the ideal yaw rate, the actual yaw rate, and the yaw rate difference are all greater than or equal to zero; or, the ideal yaw rate, the actual yaw rate, and the yaw rate difference are all less than zero (A6). The first judgment condition can be described as follows: the actual yaw rate is greater than or equal to zero, the ideal yaw rate is greater than or equal to zero, and the yaw rate difference is greater than or equal to zero; or the actual yaw rate is less than zero, the ideal yaw rate is less than zero, and the yaw rate difference is less than zero.

[0050] In the oversteer state, if the first determination condition is satisfied, it means that the response of the vehicle and the intention of the driver are in the same direction, i.e., the signs of the ideal yaw rate and the actual yaw rate have been the same, and the vehicle enters the understeer recovery state from the oversteer state. After the vehicle exits the oversteer state and enters the understeer recovery state, the vehicle enters other states after waiting for the change of subsequent parameters such as but not limited to the actual yaw rate, the ideal yaw rate, etc. When the vehicle exits the oversteer state, the vehicle enters the understeer recovery state, and the vehicle can be controlled according to a torque control strategy such as but not limited to the oversteer strategy, so as to avoid that the torque control strategy of the vehicle is immediately switched to the understeer strategy to cause further instability of the vehicle.

[0051] For example, referring to Figure 2 and Figure 3 When the vehicle is in the understeer recovery state, if the ideal yaw rate and the actual yaw rate satisfy the second determination condition, it is determined that the vehicle is in the oversteer state, and the vehicle is switched from the understeer recovery state to the oversteer state. For example, the vehicle can be assigned a torque according to a torque control strategy such as but not limited to the oversteer strategy. The second determination condition includes: the ideal yaw rate and the actual yaw rate are both greater than or equal to zero, and the yaw rate difference is less than zero; or the ideal yaw rate and the actual yaw rate are both less than zero, and the yaw rate difference is greater than or equal to zero (A7). For example, the second determination condition can be described as follows: the actual yaw rate is greater than or equal to zero, the ideal yaw rate is greater than or equal to zero, and the yaw rate difference is less than zero; or the actual yaw rate is less than zero, the ideal yaw rate is less than zero, and the yaw rate difference is greater than or equal to zero.

[0052] In the understeer recovery state, if the second determination condition is satisfied, it means that the response of the vehicle and the intention of the driver are in the same direction, i.e., the signs of the ideal yaw rate and the actual yaw rate have been the same, i.e., the directions of the ideal yaw rate and the actual yaw rate are the same, and the absolute value of the actual yaw rate is greater than that of the ideal yaw rate, which satisfies the state of the vehicle entering the oversteer state, so that the vehicle enters the oversteer state from the understeer recovery state. Subsequently, for the oversteer state, a proper torque distribution strategy can be used to control the vehicle to ensure that the vehicle does not become unstable and is adjusted to the neutral steering state as much as possible.

[0053] For example, referring to Figure 2 and Figure 3When the vehicle is in the counter hitting recovery state, if the ideal yaw rate and the actual yaw rate satisfy a third judgment condition, it is determined that the vehicle is in the first transition state, and the vehicle is switched from the counter hitting recovery state to the first transition state. Exemplarily, torque can be distributed to each drive wheel of the vehicle according to a torque control strategy such as but not limited to an oversteering strategy. The third judgment condition includes that the absolute value of the yaw rate difference is less than or equal to a set threshold value (A17). The third judgment condition can be described as follows: |yaw rate difference|≤set threshold value. When the vehicle is in the counter hitting recovery state, if the third judgment condition is satisfied, it indicates that the driver maintains the counter hitting, that is, the driver basically does not adjust the steering wheel in the counter hitting recovery state, so that the ideal yaw rate of the vehicle remains basically the same as the ideal yaw rate when the oversteering state is entered, and mainly through the action of the actual yaw rate and other factors such as the torque control strategy, the vehicle runs in the other steering direction (the direction opposite to the direction of the original actual yaw rate) and gradually recovers to a stable state, so as to accurately identify the driving intention of the driver and ensure the stability of the vehicle and prevent the vehicle from being unstable. This situation is often applied to the situation that the instability of the vehicle before is not large, so that the vehicle directly switches to the first transition state without switching to the oversteering state,

[0054] Exemplarily, reference is made to Figure 2 and Figure 3 When the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy a fourth judgment condition, it is determined that the vehicle is in the neutral steering state, and the vehicle is switched from the first transition state to the neutral steering state. Exemplarily, torque can be distributed to each drive wheel of the vehicle according to a torque control strategy such as but not limited to a neutral steering strategy. The fourth judgment condition includes that the ideal yaw rate and the actual yaw rate satisfy the third judgment condition for a duration exceeding a first time threshold value (A9). That is, the first transition state is maintained for a time exceeding the first time threshold value, and the vehicle is recovered to the neutral steering. The way in which the vehicle is adjusted to the stable state of the neutral steering when the vehicle is in the first transition state can be that the vehicle is maintained in the first transition state for a time exceeding the first time threshold value, and within the first time threshold value, the vehicle does not satisfy the condition of entering the oversteering again, so as to switch the state of the vehicle to the neutral steering state, which indicates that the vehicle has completed the adjustment to the neutral steering state.

[0055] Exemplarily, reference is made to Figure 2 and Figure 3When the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy a fifth judgment condition, the vehicle is switched from the first transition state to the over-steering state, and each drive wheel of the vehicle is assigned a torque according to the over-steering strategy. The fifth judgment condition includes that the duration for which the ideal yaw rate and the actual yaw rate satisfy the third judgment condition is not more than a first time threshold (A11). That is, within the first time threshold, the condition of |yaw rate difference|>set threshold occurs again, so that the duration for which the ideal yaw rate and the actual yaw rate satisfy the third judgment condition is not more than the first time threshold, thereby switching the vehicle from the first transition state to the over-steering state, and assigning each drive wheel of the vehicle a torque according to the over-steering strategy. When the vehicle is in the first transition state, within the first time threshold, the vehicle again satisfies the condition of entering the over-steering state, thereby indicating that the vehicle is at risk of instability again. Therefore, the vehicle is switched from the first transition state to the over-steering state again, and the vehicle is adjusted according to the torque corresponding to the over-steering state, thereby preventing the vehicle from being unstable and preventing the vehicle from frequently switching between the neutral steering state and the over-steering state.

[0056] For example, referring to Figure 2 and Figure 3 When the vehicle is in the counter-hitting recovery state, if the duration for which the counter-hitting recovery state is continuously maintained is greater than a first time threshold, it is determined that the vehicle is in the neutral steering state, and the vehicle is switched from the counter-hitting recovery state to the neutral steering state. For example, each drive wheel of the vehicle can be assigned a torque according to the neutral steering strategy (A16). That is, after the duration for which the counter-hitting recovery state is maintained is greater than the third time threshold, the vehicle is switched from the counter-hitting recovery state to the neutral steering state. For example, subsequently, each drive wheel of the vehicle can be assigned a torque according to the neutral steering strategy, and of course, other torque assignment strategies can also be used. When the vehicle is in the counter-hitting recovery state, if the duration for which the counter-hitting recovery state is continuously maintained is greater than the third time threshold, it indicates that the driver maintains counter-hitting, that is, the driver basically does not adjust the steering wheel in the counter-hitting recovery state, so that the ideal yaw rate of the vehicle remains substantially the same as the ideal yaw rate when the vehicle enters the over-steering state. The direction is mainly through the action of the actual yaw rate and the torque control strategy and other factors, causing the vehicle to quickly run in the opposite direction (the direction opposite to the original actual yaw rate direction) and gradually recover to the stable state of the neutral steering state. This situation often applies to the case where the instability of the vehicle is not large before, so that the vehicle is directly switched to the neutral steering state without switching to the over-steering state, thereby accurately identifying the driving intention of the driver, ensuring the stability of the vehicle, and preventing the vehicle from being unstable.

[0057] For example, referring to Figure 2 andFigure 3 When the vehicle is in the oversteer state, if the ideal yaw rate and the actual yaw rate satisfy a sixth determination condition, it is determined that the vehicle is in the over-recovery state, and the vehicle is switched from the over-recovery state to the oversteer state. In some embodiments, the vehicle can be assigned a torque to each drive wheel in accordance with an oversteer strategy, and of course, in other embodiments, other torque assignment strategies can be employed to assign a torque to each drive wheel of the vehicle. The sixth determination condition includes: the ideal yaw rate and the actual yaw rate are both greater than or equal to zero, and the yaw rate difference is less than zero; or, the ideal yaw rate and the actual yaw rate are both less than zero, and the yaw rate difference is greater than or equal to zero (A18). For example, the sixth determination condition can be described as follows: the actual yaw rate > 0, the ideal yaw rate > 0, and the yaw rate difference < 0; or the actual yaw rate < 0, the ideal yaw rate < 0, and the yaw rate difference > 0.

[0058] When the vehicle is in the over-recovery state, if the sixth determination condition is satisfied, it means that the driver maintains the over-recovery, i.e., the driver basically does not adjust the steering wheel in the over-recovery state, so that the ideal yaw rate of the vehicle remains substantially the same as the ideal yaw rate when the vehicle enters the over-recovery state, and mainly through the actual yaw rate and the torque control strategy and other factors, the vehicle quickly runs in the other steering direction (the direction opposite to the direction of the original actual yaw rate), but directly jumps over the over-recovery state and enters the oversteer state in the other steering direction. This situation is often applied to a situation where the previous instability of the vehicle is not large, and the rate of change of the actual yaw rate is very fast, so that when the vehicle directly changes to the other steering direction, the change rate exceeds the change rate of the ideal yaw rate, and the oversteer situation occurs again, so that the vehicle does not have time to switch to the over-recovery state and directly switches to the oversteer state. At this time, the vehicle needs to be controlled by the torque assignment strategy to suppress the oversteer to prevent the vehicle from being unstable.

[0059] It should be understood that the above only exemplarily shows several ways of exiting the over-recovery state, and in addition thereto, other ways can be employed.

[0060] The vehicle enters the over-steering state from other states, which is related to the previous state of the vehicle, the sudden change of the ideal yaw rate or the actual yaw rate of the vehicle, the sudden change of the torque, and the like. In some embodiments, the steering state judgment and torque control method can further include: determining whether the vehicle satisfies the angular velocity condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate. According to the angular velocity condition and the current state of the vehicle, it is determined whether the vehicle is in the over-steering state. That is, when determining whether the vehicle is in the over-steering state, the angular velocity condition and the current state of the vehicle are determined together. The following exemplary describes several ways of entering the over-steering state from other states.

[0061] For example, when determining whether the vehicle satisfies the angular velocity condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate, the following is referred to: Figure 2 and Figure 3 When the vehicle is currently in the over-steering state, if the ideal yaw rate and the actual yaw rate satisfy the first sub-angular velocity condition in the angular velocity condition, it is determined that the vehicle satisfies the angular velocity condition, that the vehicle is in the over-steering state, and that the vehicle is switched from the over-steering state to the over-steering state. In some embodiments, the vehicle can be assigned a torque according to the over-steering strategy, and of course, in other embodiments, other torque allocation strategies can be used to control the vehicle. The first sub-angular velocity condition includes: the actual yaw rate is less than zero, and the ideal yaw rate and the yaw rate difference are greater than or equal to zero; or, the actual yaw rate is greater than zero, and the ideal yaw rate and the yaw rate difference are less than or equal to zero (A15). For example, the first sub-angular velocity condition can be described as follows: the actual yaw rate < 0, the ideal yaw rate ≥ 0, and the yaw rate difference ≥ 0; or, the actual yaw rate > 0, the ideal yaw rate ≤ 0, and the yaw rate difference ≤ 0. When the vehicle is in the over-steering state, if the first sub-angular velocity condition is satisfied, it means that the ideal yaw rate and the actual yaw rate satisfy the angular velocity condition at this time, and the vehicle is directly determined to be in the over-steering state.

[0062] The situation can be caused by various reasons, for example, the driver may have over-steered the steering wheel to correct the previous over-steering during the previous over-steering process, but the over-steering of the steering wheel directly changes the sign (and direction) of the ideal yaw rate, and if the vehicle is not controlled by the torque strategy, the vehicle may be unstable, so the vehicle is switched from the over-steering state to the over-steering state in the embodiment of the application, and the vehicle is controlled by the torque to suppress the instability of the vehicle in time and ensure the stability of the vehicle.

[0063] For example, when determining whether the vehicle satisfies the angular velocity condition according to the current state of the vehicle, the ideal yaw rate and the actual yaw rate, reference is made to Figure 2 and Figure 3 When the vehicle is in the under-steering state, if the ideal yaw rate and the actual yaw rate satisfy the first sub-angular velocity condition in the angular velocity condition, it is determined that the vehicle satisfies the angular velocity condition, that the vehicle is in the over-steering state, and that the vehicle is switched from the under-steering state to the over-steering state. For example, the vehicle can be assigned a torque for each drive wheel in accordance with the over-steering strategy. The first sub-angular velocity condition can include, for example, that the actual yaw rate is less than zero, and the ideal yaw rate and the yaw rate difference are both greater than or equal to zero; or, that the actual yaw rate is greater than zero, and the ideal yaw rate and the yaw rate difference are both less than or equal to zero (A5). For example, the first sub-angular velocity condition can be expressed as follows: actual yaw rate < 0, ideal yaw rate ≥ 0, and yaw rate difference ≥ 0; or, actual yaw rate > 0, ideal yaw rate ≤ 0, and yaw rate difference ≤ 0. It should be understood that the above is only an example of a way of expressing the first sub-angular velocity condition, and that other ways of expressing the first sub-angular velocity condition can also be used, for example, by adding some constraints on the actual yaw rate and the ideal yaw rate when the actual yaw rate is equal to zero and the angular velocity condition is satisfied.

[0064] When the vehicle is in the under-steering state, if the first sub-angular velocity condition is satisfied, it indicates that the vehicle can be in one of the following working conditions: 1. During the under-steering process, the driver corrects the under-steering by turning the steering wheel in the opposite direction (opposite to the current steering direction), which causes the ideal yaw rate of the vehicle to change direction; 2. Similar to the eight-character working condition, the driver over-steers during the steering process, and after switching the steering direction, the steering wheel is turned at a high rate, which can cause the vehicle to enter the over-steering state, but due to the fast change rate, the vehicle does not have enough time to switch to the over-steering state, and then the driver quickly turns the steering wheel in the opposite direction of the actual yaw rate. During this process, the vehicle is prone to instability, and the embodiments of the present application determine the state of the vehicle as the over-steering state after identifying signs of instability, which facilitates subsequent targeted adjustments.

[0065] For example, reference is made to Figure 2 and Figure 3In the case that the vehicle is in the neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy the second sub-yaw rate condition in the yaw rate condition, it is determined that the vehicle satisfies the yaw rate condition, it is determined that the vehicle satisfies the over-reverse state, and the vehicle is switched from the neutral steering state to the over-reverse state. In some embodiments, the vehicle can be assigned a torque for each driving wheel according to an over-steering strategy. The second sub-yaw rate condition can include: the actual yaw rate is less than zero, the ideal yaw rate and the yaw rate difference are both greater than or equal to zero, and the absolute value of the yaw rate difference is greater than a set threshold; or, the actual yaw rate is greater than zero, and the ideal yaw rate and the yaw rate difference are both less than or equal to zero, and the absolute value of the yaw rate difference is greater than a set threshold (A12). For example, the second sub-yaw rate condition can be described as: the actual yaw rate < 0, the ideal yaw rate ≥ 0, the yaw rate difference ≥ 0, and | the yaw rate difference | > the set threshold; or, the actual yaw rate > 0, the ideal yaw rate ≤ 0, the yaw rate difference ≤ 0, and | the yaw rate difference | > the set threshold. It should be understood that the above is only an example of one way to show the second sub-yaw rate condition, and other ways can also be used, for example, the actual yaw rate can be equal to zero and satisfy some constraints of the yaw rate condition.

[0066] The situation can occur due to various reasons, for example, when the vehicle is in the neutral steering state, if the second sub-yaw rate condition is satisfied, it means that during the neutral steering process, the driver suddenly hits the steering wheel in the opposite direction of the steering direction, the steering wheel is suddenly hit in the opposite direction during the neutral steering process, causing the ideal yaw rate of the vehicle to change direction, and the response (actual yaw rate) of the vehicle often cannot keep up with the steering speed of the ideal yaw rate, and the vehicle can be unstable, at this time, the vehicle can be switched from the neutral steering state to the over-reverse state, and a torque control strategy such as but not limited to the over-steering strategy can be used to assign a torque to each driving wheel of the vehicle, so as to timely suppress the instability of the vehicle and ensure the stability of the vehicle.

[0067] The above is only an example of how other working conditions enter the over-reverse state, and it should be understood that other states can also enter the over-reverse state in addition to the above conditions. For example, the first transition state, the second transition state, or the under-steering state can also be provided with corresponding judgment conditions to enter the over-reverse state.

[0068] In addition, in addition to the above-mentioned ways, other states can also be switched to the over-steering state.

[0069] For example, when determining that the vehicle is in an over-counter-steering state based on the angular velocity condition and the vehicle's current state, refer to Figure 2 and Figure 3 When the vehicle is currently in an understeer state, if the ideal yaw rate and the actual yaw rate satisfy the seventh judgment condition, then the vehicle is determined to be in an oversteer state, and the vehicle is switched from the understeer state to the oversteer state. In some embodiments, torque can be distributed to each drive wheel of the vehicle according to the oversteer strategy; in other embodiments, the vehicle can be controlled according to other strategies. The seventh judgment condition includes: both the actual yaw rate and the ideal yaw rate are greater than or equal to zero, and the difference in yaw rates is less than zero; or, both the actual yaw rate and the ideal yaw rate are less than zero, and the difference in yaw rates is greater than zero (A13). For example, the seventh judgment condition can be expressed as follows: actual yaw rate ≥ 0, ideal yaw rate ≥ 0, yaw rate difference < 0; or, actual yaw rate < 0; ideal yaw rate < 0, yaw rate difference > 0. When the vehicle is currently in an understeer state, if the ideal yaw rate and the actual yaw rate satisfy the seventh judgment condition, it means that the ideal yaw rate and the actual yaw rate must satisfy the angular velocity condition, and the vehicle is directly determined to be in an oversteer state. This transition mainly refers to the vehicle switching from understeer to oversteer. The cause may be that the driver makes sudden back and forth turns of the steering wheel, or the vehicle's wheels experience sudden slippage, etc., causing the vehicle to switch from understeer to oversteer, which facilitates subsequent targeted torque control and prevents the vehicle from becoming unstable.

[0070] For example, when determining that the vehicle is in an over-counter-steering state based on the angular velocity condition and the vehicle's current state, refer to Figure 2 and Figure 3When the vehicle is in the neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy an eighth judging condition, the vehicle is switched from the neutral steering state to the over-steering state. In some embodiments, the vehicle can be controlled according to an over-steering strategy, and in other embodiments, the vehicle can be controlled according to other strategies. The eighth judging condition includes: the actual yaw rate and the ideal yaw rate are both greater than or equal to zero, the yaw rate difference is less than zero, and the absolute value of the yaw rate difference is greater than a set threshold value; or, the actual yaw rate and the ideal yaw rate are both less than zero, the yaw rate difference is greater than zero, and the absolute value of the yaw rate difference is greater than a set threshold value (A10). For example, the eighth judging condition can be expressed as: the actual yaw rate ≥ 0, the ideal yaw rate ≥ 0, the yaw rate difference < 0, and | the yaw rate difference | > the set threshold value; or, the actual yaw rate < 0, the ideal yaw rate < 0, the yaw rate difference > 0, and | the yaw rate difference | > the set threshold value. When the vehicle is in the neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy the eighth judging condition, it means that the ideal yaw rate and the actual yaw rate satisfy the yaw rate condition, and the vehicle is directly determined to be in the over-steering state. When the vehicle is in the neutral steering state, the error accumulation caused by the inconsistent change rate of the ideal yaw rate and the actual yaw rate can cause the vehicle to switch from the neutral steering state to the over-steering state, thereby stabilizing the vehicle and preventing the vehicle from further deteriorating in the unstable direction.

[0071] The vehicle can exit the over-steering state in other ways in addition to the above-mentioned ways. For example, referring to Figure 2 and Figure 3 When the vehicle is in the over-steering state, if the ideal yaw rate and the actual yaw rate satisfy a ninth judging condition, the vehicle is switched from the over-steering state to the first transition state, and the vehicle is controlled according to the over-steering strategy. The ninth judging condition includes: the absolute value of the yaw rate difference is less than or equal to a set threshold value (A8). For example, the ninth judging condition can be expressed as: | the yaw rate difference | ≤ the set threshold value. After satisfying the ninth judging condition, the vehicle is switched from the over-steering state to the first transition state, and the vehicle is observed to determine whether the vehicle can enter the neutral steering state after the first transition state. If the vehicle can enter the neutral steering state after the first transition state, the vehicle is determined to be able to enter the neutral steering state after the first transition state.

[0072] For example, referring to Figure 2 and Figure 3When the vehicle is in the over-steering state, if the ideal yaw rate and the actual yaw rate satisfy a tenth judgment condition, the vehicle is switched from the over-steering state to the under-steering state, and each drive wheel of the vehicle is assigned a torque according to the under-steering strategy; wherein the tenth judgment condition includes: the actual yaw rate, the ideal yaw rate and the yaw rate difference are all greater than or equal to zero; or, the actual yaw rate, the ideal yaw rate and the yaw rate difference are all less than zero (A14). Exemplarily, the tenth judgment condition can be expressed as follows: the actual yaw rate ≥ 0, the ideal yaw rate ≥ 0, and the yaw rate difference ≥ 0; or, the actual yaw rate < 0, the ideal yaw rate < 0, and the yaw rate difference < 0. The situation of this working condition may be that, in order to correct the over-steering, the correction amplitude is too large or the correction time is too long, so that the vehicle cannot be switched to the first transition state and the neutral steering state in time, and is directly switched to the under-steering state. In this process, the vehicle needs to be switched to the under-steering state in time, and the corresponding torque strategy is assigned to control the vehicle, so as to inhibit the vehicle from further deteriorating to the under-steering state, and prevent the vehicle from being unstable.

[0073] It should be understood that, in addition to the above control mode, the vehicle can also be controlled between the neutral steering and the under-steering.

[0074] Exemplarily, reference is made to Figure 2 and Figure 3 When the vehicle is in the neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy an eleventh judgment condition, the vehicle is switched from the neutral steering state to the under-steering state, and each drive wheel of the vehicle is assigned a torque according to the under-steering strategy; wherein the eleventh judgment condition includes: the actual yaw rate, the ideal yaw rate and the yaw rate difference are all greater than or equal to zero, and the absolute value of the yaw rate difference is greater than a set threshold; or, the actual yaw rate, the ideal yaw rate and the yaw rate difference are all less than zero, and the absolute value of the yaw rate difference is greater than the set threshold (A1). Exemplarily, the eleventh judgment condition can be expressed as follows: the actual yaw rate ≥ 0, the ideal yaw rate ≥ 0, the yaw rate difference ≥ 0, and |the yaw rate difference| > the set threshold; or, the actual yaw rate < 0, the ideal yaw rate < 0, the yaw rate difference < 0, and |the yaw rate difference| > the set threshold. When the vehicle is in the neutral steering state, the error accumulation caused by the inconsistent change rate of the ideal yaw rate and the actual yaw rate may cause the vehicle to be switched from the neutral steering state to the under-steering state, so as to inhibit the vehicle from being unstable, and prevent the vehicle from further deteriorating to the unstable state.

[0075] Exemplarily, reference is made to Figure 2 and Figure 3When the vehicle is in the understeering state, if the ideal yaw rate and the actual yaw rate satisfy a twelfth judgment condition, the vehicle is switched from the understeering state to a second transition state, and each drive wheel of the vehicle is assigned a torque according to the understeering strategy. The twelfth judgment condition includes that the absolute value of the yaw rate difference is less than or equal to a set threshold value (A2). Exemplarily, the twelfth judgment condition can be expressed as follows: |yaw rate difference|≤set threshold value. When the vehicle is in the understeering state, if the twelfth judgment condition is satisfied, the second transition state is entered. After the vehicle is switched to the first transition state, the vehicle is observed to determine whether the time for the vehicle to meet the neutral steering state can reach the second time threshold value, so as to determine whether the vehicle can enter the neutral steering state after the second transition state.

[0076] Exemplarily, reference is made to Figure 2 and Figure 2 When the vehicle is in the second transition state, if the ideal yaw rate and the actual yaw rate satisfy a thirteenth judgment condition, the vehicle is switched from the second transition state to the neutral steering state, and each drive wheel of the vehicle is assigned a torque according to the neutral steering strategy. The thirteenth judgment condition includes that the ideal yaw rate and the actual yaw rate satisfy the twelfth judgment condition for a duration exceeding the second time threshold value (A3), that is, if the maintenance time of the second transition state exceeds the second time threshold value. After the vehicle is switched to the first transition state, the vehicle is observed to determine whether the time for the vehicle to meet the neutral steering state can reach the second time threshold value, so as to determine whether the vehicle can enter the neutral steering state after the second transition state.

[0077] Exemplarily, reference is made to Figure 2 and Figure 2 When the vehicle is in the second transition state, if the ideal yaw rate and the actual yaw rate satisfy a fourteenth judgment condition, the vehicle is switched from the second transition state to the understeering state, and each drive wheel of the vehicle is assigned a torque according to the understeering strategy. The fourteenth judgment condition includes that the ideal yaw rate and the actual yaw rate satisfy the twelfth judgment condition for a duration not exceeding the second time threshold value (A4). That is, within the second time threshold value, the condition of |yaw rate difference|>set threshold value appears again, so that the duration for the ideal yaw rate and the actual yaw rate to satisfy the twelfth judgment condition does not exceed the second time threshold value. After the vehicle is switched to the first transition state, the vehicle is observed to determine whether the time for the vehicle to meet the neutral steering state cannot reach the second time threshold value, so as to determine that the vehicle retreats from the second transition state to the understeering state again, and the vehicle is controlled according to the understeering strategy to prevent the vehicle from being unable to reliably and stably enter the neutral steering state.

[0078] In the process of torque control of the vehicle, the vehicle can be controlled in various ways to suppress the risk of instability of the vehicle and keep the vehicle in a stable driving state. The following examples introduce several torque control methods.

[0079] For example, the steering state judgment and torque control method can further include: when the vehicle is in the over-steering state, the over-steer recovery state, the over-steering state or the first transition state, the vehicle is assigned torque according to the over-steering strategy. The embodiments of the present application summarize the commonality of torque adjustment in the over-steering state, the over-steer recovery state, the over-steering state and the first transition state, and find that the over-steering strategy can suppress the deterioration of the vehicle to the instability direction and reduce the excessive frequency of switching between different steering strategies of the vehicle, thereby increasing the risk of instability of the vehicle. Of course, in other embodiments, different torque control strategies can be used for different states, that is, as long as the torque control strategy can suppress the deterioration of the vehicle to the instability direction when the vehicle is in the respective state, it is within the protection scope of the embodiments of the present application.

[0080] For example, referring to Figure 2 and Figure 3 , the torque of each drive wheel of the vehicle can be assigned according to the over-steering strategy, which can include: in the case that the total torque of the vehicle is unchanged, the torque is transferred to the front drive wheel of the vehicle while being transferred to the drive wheel on the side opposite to the ideal yaw rate direction. The total torque of the vehicle is as unchanged as possible to ensure that the vehicle does not deteriorate to the instability direction, thereby ensuring that the driving speed of the vehicle is basically unchanged or changes less. In other embodiments, if the tendency of the vehicle to further deteriorate to the instability direction cannot be corrected, the vehicle can be prevented from further deteriorating to the instability direction by means such as but not limited to torque reduction or braking.

[0081] For example, referring to Figure 2 , the steering wheel angle is left, that is, the ideal yaw rate is left, and when the left turn over-steering occurs, the torque control strategy of transferring the torque to the front drive wheel while transferring the torque to the drive wheel on the right side of the vehicle can be used.

[0082] For example, referring to Figure 2 , the steering wheel angle is left, that is, the ideal yaw rate is left, and when the left turn over-steering occurs, the torque control strategy of transferring the torque to the front drive wheel while transferring the torque to the drive wheel on the right side of the vehicle can be used.

[0083] For example, referring to Figure 2 , the steering wheel is turned to the right, that is, the ideal yaw rate is right, and when the right turn over-steering occurs, the torque control strategy of transferring the torque to the front drive wheel while transferring the torque to the drive wheel on the left side of the vehicle can be used.

[0084] For example, referring to Figure 3 , the steering wheel is steered to the right, i.e. the ideal yaw rate is to the right, and when right turn over-steer kickback excessive steering occurs, a torque control strategy of shifting torque to the front drive wheels of the vehicle while shifting torque to the drive wheels on the left side of the vehicle can be used.

[0085] When torque is shifted to the front drive wheels of the vehicle while shifting torque to the drive wheels on the opposite side of the ideal yaw rate direction under the condition that the total torque of the vehicle is unchanged, an exemplary torque distribution strategy can be used as follows: first, the torque of the front drive wheels of the vehicle is increased and the torque of the rear drive wheels of the vehicle is decreased under the condition that the total torque of the vehicle is unchanged. Then, based on the distribution result of increasing the torque of the front drive wheels of the vehicle and decreasing the torque of the rear drive wheels of the vehicle, the torque of the drive wheels on the opposite side of the ideal yaw rate direction is increased and the torque of the drive wheels on the same side of the ideal yaw rate direction is decreased under the condition that the total torque of the vehicle is unchanged.

[0086] In addition, the steering state judgment and torque control method can also include: distributing torque to each drive wheel of the vehicle according to the under-steer strategy when the vehicle is in the under-steer state or the second transition state. The embodiments of the present application summarize the commonality of torque adjustment in the under-steer state or the second transition state, and find that the under-steer strategy can inhibit the vehicle from deteriorating in the unstable direction and can reduce the excessive frequency of switching between different steering strategies of the vehicle, thereby increasing the risk of instability of the vehicle. Of course, in other embodiments, different torque control strategies can be used for different states, i.e. as long as the torque control strategy can inhibit the vehicle from deteriorating in the unstable direction when the vehicle is in the respective state, it is within the protection scope of the embodiments of the present application.

[0087] For example, referring to Figure 4 and Figure 4 , distributing torque to each drive wheel of the vehicle according to the under-steer strategy can include: shifting torque to the rear drive wheels of the vehicle while shifting torque to the drive wheels on the opposite side of the ideal yaw rate direction under the condition that the total torque of the vehicle is unchanged. The total torque of the vehicle is kept unchanged as much as possible to ensure that the vehicle does not deteriorate in the unstable direction, thereby ensuring that the driving speed of the vehicle is basically unchanged or changes less. In other embodiments, if the tendency of the vehicle to further deteriorate in the unstable direction cannot be corrected, the vehicle can be prevented from further deteriorating in the unstable direction by means such as but not limited to torque reduction or braking.

[0088] For example, referring to Figure 5 , the steering wheel is steered to the left, i.e. the ideal yaw rate is to the left, and when left turn under-steer occurs, a torque control strategy of shifting torque to the rear drive wheels of the vehicle while shifting torque to the drive wheels on the right side of the vehicle can be used.

[0089] For example, with reference to Figure 6 When the steering wheel angle is right, i.e. the ideal yaw rate is right, and right turn under-steer occurs, a torque control strategy can be adopted to shift torque to the rear drive wheels and to the left drive wheels of the vehicle.

[0090] For example, when the total torque of the vehicle is unchanged, torque is shifted to the rear drive wheels of the vehicle and to the drive wheels on the opposite side of the ideal yaw rate direction, a torque distribution strategy can be adopted as shown below. First, when the total torque of the vehicle is unchanged, the torque of the rear drive wheels of the vehicle is increased and the torque of the front drive wheels of the vehicle is decreased. Then, based on the distribution result of increasing the torque of the rear drive wheels of the vehicle and decreasing the torque of the front drive wheels of the vehicle, when the total torque of the vehicle is unchanged, the torque of the drive wheels on the opposite side of the ideal yaw rate direction is increased and the torque of the drive wheels on the same side of the ideal yaw rate direction is decreased.

[0091] For the torque strategy control of the neutral steering state, the neutral steering strategy can be adopted to distribute torque to each drive wheel of the vehicle, and the neutral steering strategy control mode can adopt any type of torque strategy control mode.

[0092] For example, the vehicle can be a four-wheel drive vehicle, i.e. all four wheels of the vehicle are drive wheels. In some embodiments, the four-wheel drive vehicle can be an independent four-wheel drive vehicle, i.e. the four-wheel drive vehicle includes four drive wheels that independently provide driving torque. Of course, in other embodiments, the vehicle can also be a two-wheel drive, three-wheel drive, etc. vehicle, and can be a vehicle that uses independent drive or non-independent drive between drive wheels.

[0093] When the independent four-wheel drive vehicle is an independent four-wheel drive electric vehicle, with reference to ​ The torque of each drive wheel can be adjusted by the motor corresponding to the drive wheel. For example, the left front motor corresponds to the left front drive wheel of the vehicle, the right front motor corresponds to the right front drive wheel of the vehicle, the left rear motor corresponds to the left rear drive wheel of the vehicle, and the right rear motor corresponds to the right rear drive wheel of the vehicle. The torque shift distribution can be determined based on the steering state, and the torque output by the motor corresponding to the drive wheel to the drive wheel can be adjusted to achieve the torque shift distribution.

[0094] For example, in some embodiments, the state of the state machine can be used to represent the current state of the vehicle, and can include, for example, ​and the understeering state, the second transition state, the oversteering state, the first transition state, the oversteer kickback state and the kickback recovery state in Table 1 below. Among them, when the state machine displays the neutral steering state, the neutral steering strategy state bit is 1, indicating that the current vehicle distributes torque to the drive wheels according to the neutral steering strategy. When the state machine displays the understeering state or the second transition state, the understeering strategy state bit is 1, indicating that the current vehicle distributes torque to the drive wheels according to the understeering strategy. When the state machine displays the oversteering state, the first transition state, the oversteer kickback state or the kickback recovery state, the oversteering strategy state bit is 1, indicating that the current vehicle distributes torque to the drive wheels according to the oversteering strategy.

[0095] Table 1 - Steering strategy corresponding to steering state

[0096]

[0097]

[0098] In the various embodiments shown above, when the absolute value of the yaw rate difference is greater than a set threshold value, and the product of the ideal yaw rate and the actual yaw rate is less than zero, it is determined that the vehicle is in the oversteer kickback state, and the torque is distributed to each drive wheel of the vehicle according to the oversteering strategy. Compared with the existing state recognition method which only contains oversteering or understeering, the present application also compares the size and direction (positive / negative) of the actual yaw rate and the ideal yaw rate. In addition to identifying normal understeering and oversteering of the vehicle, the present application also identifies the state of the vehicle when the steering wheel is kicked back in the oversteering state, identifies the risk of instability of the vehicle in time, and controls the instability of the vehicle in time to improve the stability of the vehicle. In some embodiments, it is classified as an oversteering strategy, and the torque control is controlled according to the oversteering strategy to improve the accuracy of the vehicle state recognition, so as to better cover the possible extreme working conditions of the vehicle. In some embodiments, when the vehicle exits the oversteer kickback state, it enters the kickback recovery state and continues to control the vehicle according to the oversteering strategy, avoiding the further instability of the vehicle caused by the immediate switching of the torque control strategy of the vehicle to the understeering strategy.

[0099] This application embodiment compares the magnitude and direction of the ideal yaw rate with the actual yaw rate to determine the vehicle's current steering state in real time. Based on the identified steering state, it distributes torque to all four wheels. Through vector control of the driving torque, it assists the vehicle in following the driver's steering expectations as closely as possible during driving and steering operations. The entire steering process can be identified based on the magnitude and direction of the ideal and actual yaw rates, recognizing not only traditional understeer and oversteer but also counter-steering. The accurately identified steering state can be used to achieve the control objectives of four-wheel independent drive, increasing control accuracy.

[0100] In addition, this application embodiment also provides a steering state judgment and torque control device, which includes: a storage medium and a processor. The storage medium stores a computer program that is run by the processor. When the computer program is run by the processor, the processor executes any of the above-mentioned steering state judgment and torque control methods.

[0101] ​ A schematic block diagram of a steering state determination and torque control device 100 according to an embodiment of this application is shown. ​ As shown, the steering state determination and torque control device 100 according to an embodiment of this application may include a storage medium 110 and a processor 120. The storage medium 110 stores a computer program executed by the processor 120. When the computer program is executed by the processor 120, the processor 120 performs the steering state determination and torque control method described above according to an embodiment of this application. Those skilled in the art can understand the specific operation of the steering state determination and torque control device 100 deployment device according to the embodiments of this application in conjunction with the foregoing content. For the sake of brevity, it will not be described in detail here.

[0102] The storage medium 110 may include, for example, a memory card of a smartphone, a storage component of a tablet computer, a hard disk of a personal computer, a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a portable compact disc read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. A computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0103] Furthermore, embodiments of this application also provide a vehicle controller, see reference. ​ The vehicle controller 200 includes: any of the above-mentioned steering state judgment and torque control devices 100.

[0104] In addition, this application also provides a vehicle, as shown in the embodiments. ​The vehicle 300 comprises a vehicle body 310 and the vehicle controller 210 described above arranged on the vehicle body. The vehicle body 310 can be provided with components such as, but not limited to, a chassis, wheels, a vehicle cabin, doors, a gearbox, a drive motor, an engine, etc. The four-wheel drive vehicle can be an electric vehicle, a hybrid vehicle, a fuel vehicle, etc.

[0105] In an example, the vehicle can be a four-wheel drive vehicle, i.e. all four wheels of the vehicle are drive wheels. In some embodiments, the four-wheel drive vehicle can be an independent four-wheel drive vehicle, i.e. the four-wheel drive vehicle comprises four drive wheels that are independently provided with driving torque. Of course, in other embodiments, the vehicle can also be a two-wheel drive vehicle, a three-wheel drive vehicle, etc., and can be a vehicle that employs independent drive or non-independent drive between the drive wheels.

[0106] The present application has been described by way of the above embodiments, but it should be understood that the above embodiments are only for the purpose of illustration and description, and are not intended to limit the present application to the scope of the described embodiments. Furthermore, those skilled in the art can understand that the present application is not limited to the above embodiments, and that more variations and modifications can be made according to the teachings of the present application, and that these variations and modifications all fall within the scope of the present application. The scope of protection of the present application is defined by the appended claims and their equivalent scope.

Claims

1. A method for judging steering state and controlling torque, characterized in that, include: Obtain the vehicle's ideal yaw rate and actual yaw rate; When the vehicle meets the angular velocity condition, it is determined that the vehicle is in an over-counterattack state; The angular velocity conditions include: the absolute value of the difference in yaw angular velocity is greater than a set threshold, and the product of the ideal yaw angular velocity and the actual yaw angular velocity is less than or equal to zero; the difference in yaw angular velocity is equal to the ideal yaw angular velocity minus the actual yaw angular velocity. When the vehicle is in the excessive counter-attack state, if the ideal yaw rate and the actual yaw rate satisfy the first judgment condition, then it is determined that the vehicle is in the counter-attack recovery state. The first judgment condition includes: the ideal yaw rate, the actual yaw rate, and the difference between the yaw rates are all greater than or equal to zero; or, the ideal yaw rate, the actual yaw rate, and the difference between the yaw rates are all less than zero.

2. The steering state judgment and torque control method as described in claim 1, characterized in that, When the vehicle is in the counter-steering recovery state, if the ideal yaw rate and the actual yaw rate satisfy the second judgment condition, then the vehicle is determined to be in an oversteering state. The second judgment condition includes: both the ideal yaw rate and the actual yaw rate are greater than or equal to zero, and the difference between the yaw rates is less than zero; or, both the ideal yaw rate and the actual yaw rate are less than zero, and the difference between the yaw rates is greater than or equal to zero.

3. The steering state judgment and torque control method as described in claim 2, characterized in that, When the vehicle is in the counter-attack recovery state, if the ideal yaw rate and the actual yaw rate satisfy the third judgment condition, then the vehicle is determined to be in the first transition state. The third judgment condition includes: the absolute value of the yaw rate difference is less than or equal to the set threshold.

4. The steering state judgment and torque control method as described in claim 3, characterized in that, When the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy the fourth judgment condition, then the vehicle is determined to be in a neutral steering state. The fourth judgment condition includes: the duration for which the ideal yaw rate and the actual yaw rate satisfy the third judgment condition exceeds a first time threshold.

5. The steering state judgment and torque control method as described in claim 4, characterized in that, When the vehicle is in the first transition state, if the ideal yaw rate and the actual yaw rate satisfy the fifth judgment condition, then the vehicle is determined to be in the oversteer state. The fifth judgment condition includes: the duration for which the ideal yaw rate and the actual yaw rate satisfy the third judgment condition does not exceed a first time threshold.

6. The steering state judgment and torque control method as described in claim 1, characterized in that, When the vehicle is in the counter-steering recovery state, if the counter-steering recovery state is maintained for a continuous time longer than a third time threshold, then the vehicle is determined to be in a neutral steering state.

7. The steering state judgment and torque control method as described in claim 1, characterized in that, When the vehicle is in the oversteer state, if the ideal yaw rate and the actual yaw rate satisfy the sixth judgment condition, then the vehicle is determined to be in an oversteer state. The sixth judgment condition includes: both the ideal yaw rate and the actual yaw rate are greater than or equal to zero, and the difference between the yaw rates is less than zero; or, both the ideal yaw rate and the actual yaw rate are less than zero, and the difference between the yaw rates is greater than or equal to zero.

8. The steering state judgment and torque control method as described in claim 1, characterized in that, The method further includes: Based on the current state of the vehicle, the ideal yaw rate, and the actual yaw rate, determine whether the vehicle meets the angular velocity condition.

9. The steering state judgment and torque control method as described in claim 8, characterized in that, The step of determining whether the vehicle meets the angular velocity condition based on the vehicle's current state, the ideal yaw rate, and the actual yaw rate includes: When the vehicle is currently in an oversteer or understeer state, if the ideal yaw rate and the actual yaw rate satisfy the first sub-angular rate condition in the angular rate condition, then it is determined that the vehicle satisfies the angular rate condition. The first sub-angular velocity condition includes: the actual yaw rate is less than zero, and the difference between the ideal yaw rate and the yaw rate is greater than or equal to zero; or, the actual yaw rate is greater than zero, and the difference between the ideal yaw rate and the yaw rate is less than or equal to zero.

10. The steering state judgment and torque control method as described in claim 8, characterized in that, The step of determining whether the vehicle meets the angular velocity condition based on the vehicle's current state, the ideal yaw rate, and the actual yaw rate includes: When the vehicle is currently in a neutral steering state, if the ideal yaw rate and the actual yaw rate satisfy the second sub-angular rate condition in the angular rate condition, then it is determined that the vehicle satisfies the angular rate condition. The second sub-angular velocity condition includes: the actual yaw rate is less than zero, the ideal yaw rate and the difference between the yaw rates are both greater than or equal to zero, and the absolute value of the difference between the yaw rates is greater than the set threshold; or, the actual yaw rate is greater than zero, the ideal yaw rate and the difference between the yaw rates are both less than or equal to zero, and the absolute value of the difference between the yaw rates is greater than the set threshold.

11. The steering state judgment and torque control method as described in claim 3, characterized in that, Also includes: When the vehicle is in the over-counter-steering state, counter-steering recovery state, over-steering state, or first transition state, torque is distributed to each drive wheel of the vehicle according to the over-steering strategy.

12. The steering state judgment and torque control method as described in claim 11, characterized in that, The process of distributing torque to each drive wheel of the vehicle according to the oversteer strategy includes: With the total torque of the vehicle remaining constant, the torque is transferred to the front drive wheel of the vehicle while simultaneously being transferred to the drive wheel on the side opposite to the direction of the ideal yaw rate.

13. The steering state judgment and torque control method as described in claim 12, characterized in that, The step of transferring torque to the front drive wheels of the vehicle while simultaneously transferring it to the drive wheels on the opposite side of the ideal yaw rate direction, while keeping the total torque of the vehicle constant, includes: With the total torque of the vehicle remaining constant, the torque of the front drive wheels of the vehicle is increased, and the torque of the rear drive wheels of the vehicle is decreased. Based on the distribution result of increasing the torque of the front drive wheels and decreasing the torque of the rear drive wheels of the vehicle, while keeping the total torque of the vehicle constant, the torque of the drive wheels on the side opposite to the ideal yaw rate direction is increased, and the torque of the drive wheels on the side with the same ideal yaw rate direction is decreased.

14. A steering state judgment and torque control device, characterized in that, include: A storage medium and a processor, wherein the storage medium stores a computer program executed by the processor, the computer program, when executed by the processor, causes the processor to perform the steering state determination and torque control method as described in any one of claims 1 to 13.

15. A vehicle controller, characterized in that, include: The steering state determination and torque control device as described in claim 14.

16. A vehicle, characterized in that, include: Vehicle body; The vehicle controller as described in claim 15 is mounted on the vehicle body.

17. The vehicle as claimed in claim 16, characterized in that, The vehicle in question is an independent four-wheel drive vehicle.

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