Single-side braking auxiliary steering control method and system and vehicle

Abstract

The invention provides a single-side braking auxiliary steering control method and system and a vehicle, and the control method comprises the following steps: obtaining a steering wheel steering angle and a vehicle speed, and determining whether to execute single-side braking according to the steering wheel steering angle and the vehicle speed; if yes, the target wheel is braked at the preset target single-side braking pressure; when the ABS function is started, the real-time target unilateral brake pressure of the target wheel is adjusted in real time according to the ABS target brake pressure; calculating the average wheel end driving force of the vehicle when the ABS function is started; after the ABS function exits, the real-time wheel end driving force of the vehicle is obtained, whether the real-time wheel end driving force is larger than the average wheel end driving force or not is judged, and if yes, the real-time target single-side braking pressure of the target wheel is increased; according to the control method, cooperative control of the single-side braking auxiliary steering and the ABS function can be achieved, the single-side braking pressure is adjusted in real time after the ABS function exits, the safety of the single-side braking auxiliary steering is improved, and the abrasion degree of tires can be reduced easily.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle unilateral braking assisted steering, and in particular, to a unilateral braking assisted steering control method, system and vehicle. Background Art

[0002] Single-side brake-assisted steering is an advanced vehicle control technology, especially suitable for vehicles that need to flexibly turn in a narrow space, such as construction vehicles, forklifts, tractors, etc. This technology achieves a tighter turning radius through single-side braking (i.e., applying braking force to only one side of the vehicle's wheels or one wheel, such as a single rear wheel), allowing the vehicle to move and operate more efficiently in a limited space.

[0003] In known unilateral brake-assisted steering, for vehicle steering under different working conditions, the braking pressure applied to the wheels on one side of the vehicle is usually a fixed braking pressure. When the wheels are not locked, the greater the braking pressure, the more the turning radius of the vehicle is reduced. If the braking pressure used for assisted steering is increased too much, it may cause the wheels to lock and increase tire wear.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] According to different aspects, one of the purposes of the present application is to match ABS start-up and exit conditions to perform unilateral braking assisted steering control.

[0006] In addition, the present application is also intended to solve or alleviate other technical problems existing in the prior art.

[0007] The present application provides a unilateral braking assisted steering control method, system and vehicle. Specifically, according to one aspect of the present application, the present application provides:

[0008] A unilateral braking assisted steering control method, for a vehicle with a TCS system, comprises the following steps:

[0009] Obtaining a steering wheel steering angle and a vehicle speed, and determining whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed;

[0010] If yes, braking the target wheel with a preset target unilateral braking pressure;

[0011] When the ABS function is activated, the real-time target unilateral braking pressure of the target wheel is adjusted in real time according to the ABS target braking pressure;

[0012] Calculate the average wheel-end driving force of the vehicle when the ABS function is activated;

[0013] After the ABS function is exited, the real-time wheel-end driving force of the vehicle is obtained to determine whether the real-time wheel-end driving force is greater than the average wheel-end driving force. If so, the real-time target unilateral braking pressure of the target wheel is increased.

[0014] Optionally, according to an implementation of the present application, the following steps are included:

[0015] Obtaining the driver's target driving force of the front wheels and the front wheel end driving force;

[0016] In response to the front wheel end driving force being less than the driver target driving force of the front wheels, the real-time target single-sided braking pressure of a target wheel among the rear wheels of the vehicle is reduced.

[0017] Optionally, according to an embodiment of the present application, when the ABS function is started, the real-time target unilateral braking pressure is set to the product of the ABS target braking pressure and a preset first limiting coefficient.

[0018] Optionally, according to an embodiment of the present application, the following steps are also included:

[0019] The slip rate of the target wheel is obtained. When the slip rate of the target wheel is higher than a preset slip rate upper limit, the real-time target unilateral braking pressure is reduced. When the slip rate of the target wheel is lower than a preset slip rate lower limit, the real-time target unilateral braking pressure is increased until the slip rate of the target wheel is between the slip rate upper limit and the slip rate lower limit.

[0020] Optionally, according to one embodiment of the present application, when lowering the real-time target unilateral braking pressure, the reduction speed of the real-time target unilateral braking pressure is set to be proportional to the difference between the slip rate of the target wheel and the upper limit of the slip rate; when raising the real-time target unilateral braking pressure, the increase speed of the real-time target unilateral braking pressure is set to be proportional to the difference between the lower limit of the slip rate and the slip rate of the target wheel.

[0021] Optionally, according to an implementation of the present application, the following steps are included:

[0022] Get the current vehicle speed and road adhesion coefficient;

[0023] In response to the current vehicle speed being less than a preset vehicle speed lower limit and the current road adhesion coefficient being less than a preset road adhesion coefficient lower limit, the target wheel is braked while keeping the current brake pressure of the target wheel unchanged.

[0024] Optionally, according to an implementation of the present application, the following steps are included:

[0025] In response to the current vehicle speed being greater than a preset vehicle speed lower limit and the current road surface adhesion coefficient being less than a preset road surface adhesion coefficient lower limit, the unilateral brake assisted steering is not performed.

[0026] According to another aspect of the present application, the present application provides a unilateral braking assisted steering control system for a vehicle having a TCS system, comprising:

[0027] The acquisition module acquires the steering wheel steering angle and vehicle speed, acquires the ABS target braking pressure when the ABS function is activated, calculates the average wheel-end driving force of the vehicle when the ABS function is activated, and acquires the real-time wheel-end driving force of the vehicle after the ABS function is exited;

[0028] a judgment module, which determines whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed, and after the ABS function is exited, determines whether the real-time wheel-end driving force is greater than the average wheel-end driving force;

[0029] A control module, which brakes the target wheel with a preset target unilateral braking pressure when the judgment module determines to execute unilateral braking, adjusts the real-time target unilateral braking pressure of the target wheel in real time according to the ABS target braking pressure when the ABS function is started, and increases the real-time target unilateral braking pressure of the target wheel when the real-time wheel-end driving force is greater than the average wheel-end driving force after the ABS function is exited.

[0030] According to yet another aspect of the present application, the present application provides a vehicle, which includes the above-mentioned unilateral braking assisted steering control system, TCS system and ABS system.

[0031] Benefits of this application include:

[0032] 1. The unilateral braking assisted steering control method of the present application realizes the coordinated control of unilateral braking assisted steering with ABS and TCS systems. When the ABS function is activated, the unilateral braking pressure is adjusted according to the ABS target braking pressure to prevent the target wheel of the unilateral braking from locking. After the ABS function is exited, the adjustment characteristics of the vehicle driving force of the TCS system can be used to judge the change of the road adhesion coefficient through the change of the wheel-end driving force, and the unilateral braking pressure is adjusted accordingly to improve the performance of unilateral braking assisted steering.

[0033] 2. The unilateral braking assisted steering control method of the present application can utilize the TCS system to adjust the vehicle driving force in real time, make a quick judgment when the front wheel of the vehicle enters a low adhesion coefficient road surface from a high adhesion coefficient road surface, and control the unilateral braking pressure of the rear wheel of the vehicle in advance, thereby realizing a quick response of the unilateral braking pressure to the change of road conditions, improving the safety of unilateral braking assisted steering when the vehicle enters a low adhesion coefficient road surface from a high adhesion coefficient road surface, and reducing the degree of wheel wear;

[0034] 3. The unilateral braking assisted steering control method of the present application can also adjust the braking pressure of the vehicle's unilateral braking according to the slip rate of the target wheel, so that the wheel slip rate is always within the preset slip rate range, avoiding the extreme situation of excessive unilateral braking pressure, reducing the possibility of wheel locking and excessive wear, and ensuring that a suitable auxiliary steering torque can always be provided for vehicle steering. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The above and other features of the present application will become apparent with reference to the accompanying drawings, in which:

[0036] Figure 1 A schematic flow chart of a unilateral braking assisted steering control method proposed according to an embodiment of the present application is shown;

[0037] Figure 2 A comparison diagram of the target unilateral braking pressure and the slip ratio of the target wheel when the unilateral braking assisted steering control method proposed in one embodiment of the present application is adopted is shown;

[0038] Figure 3 A module schematic diagram of a unilateral braking assisted steering control system proposed according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0039] It is easy to understand that according to the technical solution of the present application, without changing the essential spirit of the present application, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the entirety of the present application or as a limitation or restriction on the technical solution of the present application.

[0040] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directional terms should not be interpreted as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for description and distinction purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components or the order or assembly order of the components.

[0041] In known unilateral brake-assisted steering, a fixed brake pressure is usually used to brake the wheel on one side to assist the vehicle in steering (especially when the steering power is insufficient to achieve a small steering radius). When the ABS (Anti-lock Braking System) system intervenes, the fixed brake pressure used to assist the steering may affect the anti-lock effect of the ABS system, so that the ABS function cannot be well implemented. In addition, when the road adhesion coefficient changes, for example, when the vehicle enters a high adhesion coefficient road from a low adhesion coefficient road and enters a low adhesion coefficient road from a high adhesion coefficient road, it is impossible to adjust the unilateral brake pressure immediately. Either the unilateral brake pressure is too large, reducing the safety of the vehicle when steering, or the unilateral brake pressure is too small, so that it is impossible to provide sufficient auxiliary steering torque during unilateral brake-assisted steering.

[0042] The unilateral braking auxiliary steering control method of the present application combines the ABS system and the TCS system to realize accurate and instant control of the unilateral braking pressure. When the ABS system is working, the unilateral braking pressure is adjusted according to the ABS target braking pressure so as not to interfere with the operation of the ABS system and not to affect the anti-lock effect of the ABS system. When the vehicle exits the ABS function and drives from a low-adhesion coefficient road surface to a high-adhesion coefficient road surface, the possible changes in road conditions can be judged in real time through the working characteristics of the TCS system to determine whether the unilateral braking pressure can be increased while ensuring the safety of braking and steering to provide a larger auxiliary steering torque.

[0043] refer to Figure 1 , which shows a flow chart of a control method for unilateral braking assisted steering according to an embodiment of the present application, Figure 1 S100-S500 in the control method correspond to each step in the control method. The control method is a pressure adaptive control method, which can use different control strategies to adjust the unilateral braking pressure applied to the target wheel when the ABS function is activated and exited, and includes the following steps:

[0044] S100: Acquire a steering wheel steering angle and a vehicle speed, and determine whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed;

[0045] S200: If yes, braking the target wheel with a preset target unilateral braking pressure;

[0046] S300: when the ABS function is activated, adjusting the real-time target unilateral braking pressure of the target wheel according to the ABS target braking pressure in real time;

[0047] S400: Calculate the average wheel-end driving force of the vehicle when the ABS function is activated;

[0048] S500: After the ABS function is exited, the real-time wheel-end driving force of the vehicle is obtained to determine whether the real-time wheel-end driving force is greater than the average wheel-end driving force. If so, the real-time target unilateral braking pressure of the target wheel is increased.

[0049] It should be understood that "unilateral braking" in this application refers to braking by applying unilateral braking pressure to a single wheel or a single wheel (for example, the inner rear wheel or the outer rear wheel when turning), and "target unilateral braking pressure" refers to the unilateral braking pressure theoretically applied to the target wheel when the vehicle performs unilateral braking to assist steering, and is not the braking pressure on the wheel when the vehicle is normally braked (without unilateral braking assistance).

[0050] The activation of the unilateral brake assisted steering function is usually determined based on the steering wheel angle and vehicle speed, because the unilateral brake assisted steering function is usually activated when the steering wheel is turned to the extreme position and it is still difficult to provide the target steering radius, so as to provide the vehicle with additional steering torque to achieve the target steering condition. When the vehicle speed is too high, the unilateral brake assisted steering function is usually not activated to ensure the steering stability of the vehicle.

[0051] When the ABS function of the vehicle is activated, the ABS system will provide an ABS target brake pressure as the critical value of the wheel brake pressure. When the wheel brake pressure is greater than the ABS target brake pressure, the wheel may lock. Therefore, when the ABS function is activated, the brake pressure of all wheels should be controlled to be less than the ABS target brake pressure. For unilateral brake assisted steering control, when the ABS function is activated, the real-time target unilateral brake pressure of the target wheel is adjusted in real time according to the ABS target brake pressure, that is, the unilateral brake pressure of the target wheel is not greater than the ABS target brake pressure, to prevent the target wheel from locking due to excessive brake pressure, causing tire wear or safety problems during steering.

[0052] In one embodiment of the present application, when the ABS function is activated, the real-time target unilateral braking pressure is set to the product of the ABS target braking pressure and a preset first limiting coefficient, wherein the preset first limiting coefficient is less than 1. In this way, when the ABS function is activated, the real-time target unilateral braking pressure is always limited to below the ABS target braking pressure, thereby preventing the target wheel braking pressure from being too high and causing the wheel to lock.

[0053] For the vehicle ABS system, after the ABS function is activated, there may be a variety of situations that make the vehicle no longer need the ABS function, so that the ABS function automatically exits, such as the vehicle no longer braking, the vehicle speed is lower than a certain limit, or the vehicle enters a high adhesion coefficient road from a low adhesion coefficient road. In the case where the vehicle enters a high adhesion coefficient road from a low adhesion coefficient road, the real-time target unilateral braking pressure of the target wheel can be appropriately increased to provide a larger auxiliary steering torque, and the wheel will not be locked. In one embodiment of the present application, it is determined whether the current ABS function exit is due to this situation based on the change in the driving force of the vehicle with the TCS system.

[0054] The full name of the TCS system is the vehicle traction control system (TCS, Traction Control System), which improves the driving condition of the vehicle by controlling the traction, that is, the driving force, to prevent the vehicle from slipping or losing directional control while driving. The working principle of the TCS system is based on the real-time monitoring of the wheel speed by the wheel speed sensor. When the vehicle is driving on a slippery road or under rapid acceleration, the drive wheel may slip. At this time, the TCS system will quickly detect the speed difference between the drive wheel and the non-drive wheel, and initiate a series of countermeasures to regulate the vehicle's power output. When the vehicle enters a low-adhesion road from a high-adhesion road, the TCS system will reduce the vehicle's wheel-end driving force, that is, the vehicle's wheel-end driving force is less than the driver's target driving force, to prevent the wheels from locking or slipping; when the vehicle enters a high-adhesion road from a low-adhesion road, the TCS system will appropriately increase the vehicle's wheel-end driving force (within the driver's target driving force range) to improve the vehicle's acceleration performance. Therefore, after the ABS function is exited, if the real-time wheel-end driving force of the vehicle is greater than the average wheel-end driving force of the vehicle when the ABS function is activated, it proves that the TCS system has increased the wheel-end driving force of the vehicle. It can be judged from this that the vehicle has entered a high-adhesion coefficient road surface from a low-adhesion coefficient road surface at this time. It is precisely because of this that the ABS function is exited, so the real-time target unilateral braking pressure of the target wheel can be increased at this time to provide a larger auxiliary steering torque. In this way, the unilateral braking assisted steering control method of the present application realizes the coordinated control of unilateral braking assisted steering with the ABS system and the TCS system, not only when the ABS system is running, the unilateral braking pressure of the unilateral braking assisted steering can be adjusted so that it does not affect the function of the ABS system, but also when the ABS system is exited, the real-time target unilateral braking pressure can be instantly adjusted according to the control information of the TCS system to provide a larger auxiliary steering torque.

[0055] In one embodiment of the present application, the unilateral braking assisted steering control method further includes the following steps:

[0056] Obtaining the driver's target driving force of the front wheels and the front wheel end driving force;

[0057] In response to the front wheel end driving force being less than the driver target driving force for the front wheels, the real-time target single-sided braking pressure of a target wheel among the rear wheels of the vehicle is reduced.

[0058] For unilateral braking assisted steering, a single rear wheel is usually selected as the target wheel for unilateral braking to apply braking pressure to assist steering, which does not change the longitudinal force of the front wheel and is conducive to improving steering stability. As for the control of the TCS system, especially for front-wheel drive vehicles, the adjustment of the wheel-end driving force is the driving force adjustment for the front wheels, that is, when the front wheels of the vehicle drive from a low-adhesion coefficient road surface to a high-adhesion coefficient road surface or from a high-adhesion coefficient road surface to a low-adhesion coefficient road surface, the TCS system will immediately adjust the driving force of the front wheels of the vehicle. Therefore, as long as the driving force adjustment of the TCS system knows that the front wheels of the vehicle have driven from a high-adhesion coefficient road surface to a low-adhesion coefficient road surface, the target unilateral braking pressure of the target wheel in the rear wheels of the vehicle can be immediately reduced to improve the response speed of the control, so that the rear wheels are prepared to enter the low-adhesion coefficient road surface in advance without locking and slipping. In this embodiment, it is first determined whether the front wheel end driving force is less than the driver's target driving force of the front wheel. If it is less than, it proves that the TCS system has limited the front wheel driving force, and the front wheel of the vehicle has entered a low adhesion coefficient road surface from a high adhesion coefficient road surface. At this time, the real-time target unilateral braking pressure of the target wheel in the rear wheel is directly reduced in advance to prevent the target wheel in the rear wheel from locking or slipping due to control delay when entering the low adhesion coefficient road surface, thereby reducing the service life of the tire. By adjusting the real-time target unilateral braking pressure of the target wheel in the rear wheel in advance, the anti-lock function of the ABS system can also be achieved to a certain extent, so that when the vehicle continuously passes through a road surface with alternating adhesion coefficients, the ABS system does not need to be turned on and off multiple times.

[0059] In one embodiment of the present application, the unilateral braking assisted steering control method further includes the following steps:

[0060] The slip rate of the target wheel is obtained. When the slip rate of the target wheel is higher than a preset slip rate upper limit, the real-time target unilateral braking pressure is reduced. When the slip rate of the target wheel is lower than a preset slip rate lower limit, the real-time target unilateral braking pressure is increased until the slip rate of the target wheel is between the slip rate upper limit and the slip rate lower limit.

[0061] refer to Figure 2 , which shows a comparison diagram of the target unilateral braking pressure and slip rate of the target wheel when the unilateral braking assisted steering control method proposed in one embodiment of the present application is adopted. Figure 2 P0 in is the preset target single-side braking pressure. Figure 2 It can be seen that, overall, when the slip rate of the target wheel is within the preset slip rate range, that is, between the preset slip rate upper limit s1 and the slip rate lower limit s2 (such as Figure 2The target unilateral braking pressure remains unchanged. At this time, the wheel has an ideal slip ratio and will not lock. A large braking pressure can also be applied to the wheel to assist steering. When the slip ratio of the target wheel increases to a value higher than the upper slip ratio limit s1 (for example, the vehicle suddenly drives from a high-adhesion coefficient road surface to a low-adhesion coefficient road surface), for example Figure 2 At moments t1 and t5 in the figure, if the wheel slip rate is too large and the wheel is close to locking, it is necessary to appropriately reduce the target unilateral braking pressure to prevent wheel locking and reduce wheel wear. In the process of reducing the target unilateral braking pressure, monitor the change in slip rate in real time. When the slip rate of the target wheel is reduced to below the upper slip rate limit s1, the target unilateral braking pressure at this time can be kept unchanged. When the slip rate of the target wheel is reduced to below the lower slip rate limit s2 (for example, the vehicle suddenly drives from a low adhesion coefficient road surface to a high adhesion coefficient road surface), for example Figure 2 At the t3 moment in the above, the wheel slip ratio is relatively low at this moment, and the wheel can bear a part of the braking pressure again without locking, thus providing a higher steering torque to assist steering, and the target unilateral braking pressure can be appropriately increased. In the process of increasing the target unilateral braking pressure, the change of the slip ratio is monitored in real time. When the slip ratio of the target wheel is increased to above the slip ratio lower limit s2, the target unilateral braking pressure at this moment can be kept unchanged. In this way, in the process of adjusting the real-time target unilateral braking pressure of the target wheel when the ABS function is turned on and off, the target unilateral braking pressure is further adjusted and limited by the slip ratio of the target wheel, so that the slip ratio of the target wheel is within the preset slip ratio range as much as possible, preventing the real-time target unilateral braking pressure from being increased too much to cause wheel locking, and also being able to provide a larger steering torque as much as possible within the safe slip ratio range for assisting steering.

[0062] In one embodiment of the present application, when lowering the target unilateral braking pressure, the reduction speed of the real-time target unilateral braking pressure is set to be proportional to the difference between the slip rate of the target wheel and the upper limit of the slip rate; when raising the target unilateral braking pressure, the increase speed of the real-time target unilateral braking pressure is set to be proportional to the difference between the lower limit of the slip rate and the slip rate of the target wheel.

[0063] In this embodiment, the adjustment of the target unilateral brake pressure is related to the difference between the slip rate and the upper limit of the slip rate and the lower limit of the slip rate. That is to say, the speed of increasing and decreasing the brake pressure is not fixed for all slip rates. For example, if the current slip rate is much higher than the upper limit of the slip rate, for example, 0.2 or more higher than the upper limit of the slip rate, the brake pressure will be reduced at a faster speed than if the current slip rate is only slightly higher than the upper limit of the slip rate, for example, 0.05 or less higher than the upper limit of the slip rate. In this embodiment, the reduction speed is proportional to the difference between the slip rate of the target wheel and the upper limit of the slip rate, that is, when the current slip rate is 0.2 higher than the upper limit of the slip rate, the speed of reducing the brake pressure should be 4 times that when the current slip rate is 0.05 higher than the upper limit of the slip rate. The same is true when the target unilateral brake pressure needs to be increased. In this way, the brake pressure can be controlled more quickly and accurately, so that the slip rate can be adjusted to the preset slip rate range more quickly.

[0064] In one embodiment of the present application, the control method further includes the following steps:

[0065] Get the current vehicle speed and road adhesion coefficient;

[0066] In response to the current vehicle speed being less than a preset vehicle speed lower limit and the current road adhesion coefficient being less than a preset road adhesion coefficient lower limit, the target wheel is braked while keeping the current target unilateral braking pressure of the target wheel unchanged.

[0067] In one embodiment of the present application, the control method further includes the following steps:

[0068] In response to the current vehicle speed being greater than a preset vehicle speed lower limit and the current road surface adhesion coefficient being less than a preset road surface adhesion coefficient lower limit, the unilateral brake assisted steering is not performed.

[0069] The above two embodiments involve unilateral braking assisted steering control under extreme working conditions. The current road adhesion coefficient can be estimated by the TCS system. If the current road adhesion coefficient is less than the preset lower limit of the road adhesion coefficient, for example, less than 0.3, the rolling friction that the road surface can provide is very small, and the wheels are easy to slip. Slight changes in the longitudinal force of the wheels may cause the wheels to become unstable, resulting in side slip or tail swing, which is not conducive to steering safety. If the vehicle speed is relatively low at this time, for example, less than the preset lower limit of the vehicle speed, such as 15km / h, due to the relatively low speed, under the condition of stable longitudinal force, the possibility of side slip or tail swing of the vehicle itself is not high, then the current target unilateral braking pressure is kept unchanged for braking to prevent its longitudinal force from changing frequently, and a certain steering torque can also be provided to assist steering. However, if the vehicle speed is high at this time, for example, the vehicle speed is greater than the preset lower speed limit - for example, 15km / h, if additional braking force is applied to the wheels to assist steering during turning, it may cause the vehicle to skid or drift. At this time, unilateral braking assisted steering will not be performed directly, that is, unilateral braking pressure will not be applied to the target wheel during turning, so as to prevent unstable operating conditions of the vehicle during turning.

[0070] Another aspect of the present application also provides a unilateral braking assisted steering control system, referring to Figure 3 , which shows a module schematic diagram of a unilateral braking assisted steering control system 10 proposed according to an embodiment of the present application. The unilateral braking assisted steering control system 10 includes:

[0071] Acquisition module 1, which acquires the steering wheel steering angle and vehicle speed, acquires the ABS target braking pressure when the ABS function is activated and calculates the average wheel-end driving force of the vehicle when the ABS function is activated, and acquires the real-time wheel-end driving force of the vehicle after the ABS function is exited;

[0072] A judgment module 2, which determines whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed, and after the ABS function is exited, determines whether the real-time wheel-end driving force is greater than the average wheel-end driving force;

[0073] The control module 3 brakes the target wheel with a preset target unilateral braking pressure when the judgment module 2 judges to execute unilateral braking, and adjusts the real-time target unilateral braking pressure of the target wheel in real time according to the ABS target braking pressure when the ABS function is started, and increases the real-time target unilateral braking pressure of the target wheel when the real-time wheel-end driving force is greater than the average wheel-end driving force after the ABS function is exited.

[0074] The unilateral braking assisted steering control system 10 has all the beneficial technical effects of the aforementioned control method, which will not be repeated here.

[0075] Another aspect of the present application provides a vehicle, which includes the unilateral brake assist steering control system, the TCS system and the ABS system as described above.

[0076] The vehicle has all the beneficial technical effects of the aforementioned control method, which will not be repeated here.

[0077] It should be understood that the unilateral brake assist steering control system of the present application can be installed on various vehicles, including cars, trucks, buses, hybrid vehicles, pure electric vehicles, etc. Therefore, the subject matter of the present application is also intended to protect various vehicles equipped with the unilateral brake assist steering control system of the present application.

[0078] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present application should be within the legal protection scope of the present application.

Claims

1. A unilateral braking assisted steering control method for a vehicle with a TCS system, characterized in that: The steps include: Acquiring a steering wheel steering angle and a vehicle speed, and determining whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed; If yes, braking the target wheel with a preset target unilateral braking pressure; When the ABS function is activated, the real-time target unilateral braking pressure of the target wheel is adjusted in real time according to the ABS target braking pressure; Calculate the average wheel-end driving force of the vehicle when the ABS function is activated; After the ABS function is exited, the real-time wheel-end driving force of the vehicle is obtained to determine whether the real-time wheel-end driving force is greater than the average wheel-end driving force. If so, the real-time target unilateral braking pressure of the target wheel is increased.

2. The unilateral braking assisted steering control method according to claim 1, characterized in that: The steps include: Obtaining the driver's target driving force of the front wheels and the front wheel end driving force; In response to the front wheel end driving force being less than the driver target driving force of the front wheels, the real-time target single-sided braking pressure of a target wheel among the rear wheels of the vehicle is reduced.

3. The unilateral braking assisted steering control method according to claim 1, characterized in that: When the ABS function is activated, the real-time target unilateral braking pressure is set to the product of the ABS target braking pressure and a preset first limiting coefficient.

4. The unilateral braking assisted steering control method according to claim 1, characterized in that: The following steps are also included: The slip rate of the target wheel is obtained. When the slip rate of the target wheel is higher than a preset slip rate upper limit, the real-time target unilateral braking pressure is reduced. When the slip rate of the target wheel is lower than a preset slip rate lower limit, the real-time target unilateral braking pressure is increased until the slip rate of the target wheel is between the slip rate upper limit and the slip rate lower limit.

5. The unilateral braking assisted steering control method according to claim 4, characterized in that: When lowering the real-time target unilateral braking pressure, the speed at which the real-time target unilateral braking pressure is lowered is set proportional to the difference between the slip rate of the target wheel and the upper limit of the slip rate; when raising the real-time target unilateral braking pressure, the speed at which the real-time target unilateral braking pressure is raised is set proportional to the difference between the lower limit of the slip rate and the slip rate of the target wheel.

6. The unilateral braking assisted steering control method according to any one of claims 1 to 5, characterized in that: The steps include: Get the current vehicle speed and road adhesion coefficient; In response to the current vehicle speed being less than a preset vehicle speed lower limit and the current road adhesion coefficient being less than a preset road adhesion coefficient lower limit, the target wheel is braked while keeping the current brake pressure of the target wheel unchanged.

7. The unilateral braking assisted steering control method according to claim 6, characterized in that: The steps include: In response to the current vehicle speed being greater than a preset vehicle speed lower limit and the current road surface adhesion coefficient being less than a preset road surface adhesion coefficient lower limit, the unilateral brake assisted steering is not performed.

8. A unilateral braking assisted steering control system for a vehicle with a TCS system, characterized in that: include: An acquisition module, which acquires the steering wheel steering angle and vehicle speed, acquires the ABS target braking pressure when the ABS function is activated and calculates the average wheel-end driving force of the vehicle when the ABS function is activated, and acquires the real-time wheel-end driving force of the vehicle after the ABS function is exited; a judgment module, which determines whether to perform unilateral braking according to the steering wheel steering angle and the vehicle speed, and after the ABS function is exited, determines whether the real-time wheel-end driving force is greater than the average wheel-end driving force; A control module, which brakes the target wheel with a preset target unilateral braking pressure when the judgment module determines to execute unilateral braking, adjusts the real-time target unilateral braking pressure of the target wheel in real time according to the ABS target braking pressure when the ABS function is started, and increases the real-time target unilateral braking pressure of the target wheel when the real-time wheel-end driving force is greater than the average wheel-end driving force after the ABS function is exited.

9. A vehicle, characterized in that: The vehicle comprises the single-sided brake assist steering control system according to claim 8, a TCS system and an ABS system.

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