Vehicle steering control method and control unit

Abstract

The invention provides a steering control method and a control unit for a vehicle. The method includes determining a target driving torque based on a driving torque requested by a driver of the vehicle and a target braking torque in response to a function activation signal or a function exit signal of a steering assist function of the vehicle, such that during activation or exit of the steering assist function, the target driving torque is activated by the driver of the vehicle; the vehicle speed change is smaller than the vehicle speed change threshold value or the acceleration change is smaller than the acceleration change threshold value, so that the smoothness of the vehicle reaches the level that a driver does not sense activation or quit of the steering auxiliary function; wherein the target braking torque is generated by the steering assistance function and is used for assisting the vehicle in achieving the target turning radius and / or the target steering angle.

Description

Technical Field

[0001] The present invention generally relates to the technical field of vehicle control. Specifically, the present invention relates to a method for vehicle steering control and a corresponding control unit. Background Art

[0002] The steering assist function of a vehicle aims to provide a more relaxed and precise steering operation for the driver. However, currently, there is a jerky phenomenon when this function is activated or deactivated, resulting in discontinuous vehicle behavior during the function switching process, which affects the driving experience of vehicle users. Summary of the Invention

[0003] In this context, according to an embodiment of one aspect of the present invention, there is provided a method for vehicle steering control, including: in response to a function activation signal or a function deactivation signal of the vehicle's steering assist function, determining a target drive torque based on the drive torque requested by the vehicle driver and the target braking torque, so that during the activation or deactivation of the steering assist function, the vehicle speed change is less than the vehicle speed change threshold or the acceleration change is less than the acceleration change threshold, thereby enabling the vehicle ride comfort to reach a level where the driver is unaware of the activation or deactivation of the steering assist function; wherein, the target braking torque is generated by the steering assist function and is used to assist the vehicle in achieving the target turning radius and / or the target steering angle.

[0004] According to an embodiment of another aspect of the present invention, there is provided a control unit for controlling vehicle steering, including a memory and one or more processors. Instructions are stored in the memory, and when executed by the one or more processors, the one or more processors implement the method as described above.

[0005] According to an embodiment of still another aspect of the present invention, there is provided a computer-readable storage medium storing executable instructions, and when the instructions are executed, one or more processors are caused to execute the method as described above.

[0006] According to an embodiment of yet another aspect of the present invention, there is provided a computer program product, which includes instructions that, when executed by one or more processors, cause the one or more processors to execute the method as described above. Brief Description of the Drawings

[0007] From the following detailed description in conjunction with the accompanying drawings, the technical solutions of the present invention will become clearer. It can be understood that these drawings are only for illustrative purposes and are not intended to limit the protection scope of the present invention.

[0008] Figure 1 is a schematic block diagram of a vehicle steering control system according to an embodiment of the present invention.

[0009] Figure 2 Schematically shows the state transition of the steering assist function of a vehicle.

[0010] Figure 3 Is a flowchart of a vehicle steering control method according to an embodiment of the present invention.

[0011] Figure 4 Is a flowchart of a vehicle steering control method according to another embodiment of the present invention. Detailed implementation manners

[0012] The inventors found through research that the reason for the jerks generated during the activation or deactivation of the vehicle steering assist function is that in order to achieve the target turning radius and / or target steering angle, this function generates a target braking torque. For example, this target braking torque is applied to the inner steering wheel of the vehicle. However, due to the failure of the control of the driving torque to fully cooperate with the braking torque, the switching of the steering assist function causes the unevenness of the vehicle driving behavior. This will cause the vehicle's dynamic response to be not smooth enough during the switching process of the driving assistance function, thus affecting the driving experience of the vehicle user.

[0013] In response to this, embodiments of the present invention propose a steering control method and a control unit for a vehicle. By precisely controlling the cooperation between the driving torque and the braking torque of the vehicle, the smoothness of the vehicle during the switching process of the driving assistance function reaches a level where the driver is unaware. Specifically, embodiments of the present invention involve performing imperceptible control in response to the state transition (such as activation or deactivation) of the steering assist function. This imperceptible control can achieve the implicit activation and implicit deactivation of the steering assist function, thereby ensuring that the driver does not feel any discomfort or jerks during the function switching process.

[0014] Next, the detailed implementation manners of the present invention will be introduced in conjunction with the accompanying drawings.

[0015] Embodiments of one aspect of the present invention relate to a vehicle steering controller system and its control unit. Figure 1 Shows a vehicle steering control system 100 according to an embodiment of the present invention, which is provided on a vehicle and is an in-vehicle system. As Figure 1 Shown, the steering control system 100 includes a sensor unit 10, a state machine 20, a control unit 30, and an execution unit 40.

[0016] The sensor unit 10 is used to sense (collect) information related to the vehicle steering state and driver operation during the vehicle steering process. For example, vehicle speed, accelerator pedal stroke, the force applied by the driver to the accelerator pedal, the steering force applied by the driver through the steering wheel (the steering wheel angle requested by the driver can be derived based on this steering force), and the door status signal used to determine whether the driver has left the vehicle, etc. It can be understood that the above information can be directly obtained through the measurement values of the sensors, or can be obtained through further calculation and processing based on the measurement values of the sensors.

[0017] In one embodiment, the sensor unit 10 may include sensors for sensing information related to the vehicle steering state and driver operation, and may also include sensors for receiving information related to the vehicle steering state and driver operation. For example, receiving information related to the vehicle steering state and driver operation from roadside facilities, other vehicles, or cloud servers via V2X communication (vehicle-to-everything communication).

[0018] The state machine 20 is used to provide the current state of the vehicle's steering assistance function. The states of the vehicle assistance function include: standby state (Standby), activation state (Activation), and ramping-off state (Ramping off). The current state of the steering assistance function is one of these three states. For example, Figure 2 schematically shows the state transition of the steering assistance function. Refer to Figure 2 , the horizontal axis t represents time, and the vertical axis S represents the state signal of the steering assistance function. Among them, stage ① represents the standby state; stage ② represents the activation state; stage ③ represents the ramping-off state; stage ④ is the same as stage ① and represents the standby state.

[0019] In one embodiment, in response to the function activation signal S_a, the steering assistance function switches from the standby state to the activation state. In response to the function deactivation signal S_de (i.e., the function deactivation signal), the steering assistance function enters the ramping-off state from the activation state, and after a predetermined duration (i.e., the duration of the ramping-off state), it switches to the standby state. When the preset function trigger conditions are met, the function activation signal S_a will be triggered. The function trigger conditions include, for example, that the current steering wheel angle is greater than the steering wheel angle threshold preset for function triggering, and the current vehicle speed is within the vehicle speed range preset for function triggering. When the function trigger conditions are no longer met, the function deactivation signal S_de will be triggered. For example, the current steering wheel angle is less than or equal to the steering wheel angle threshold preset for function triggering, or the current vehicle speed exceeds the vehicle speed range preset for function triggering.

[0020] The control unit 30 is configured to execute the vehicle steering control method according to the embodiments of the present invention. Specifically, in response to receiving a function activation signal or a function deactivation signal, the control unit 30 executes a seamless control method to ensure a smooth transition of the vehicle driving behavior during the state switching of the steering assist function, thereby eliminating the possible unevenness during the function switching process and enhancing the driving experience of vehicle users.

[0021] In one embodiment, the control unit 30 may be implemented to include a plurality of functional modules, which may be implemented on the same chip or circuit, or on different chips or circuits.

[0022] In one embodiment, the control unit 30 may be implemented in a hardware manner, or a software manner, or a combination of software and hardware.

[0023] In one embodiment, the control unit 30 is implemented to include a memory and one or more processors. The memory stores instructions that, when executed by the one or more processors, cause the one or more processors to implement the vehicle steering control method according to the embodiments of the present invention.

[0024] In one embodiment, the control unit 30 may be deployed in the vehicle's electronic control unit (ECU), vehicle body controller (VCU), or domain controller (such as a power domain controller or a chassis domain controller). In an implementation where the control unit 30 is implemented to include a plurality of functional modules, these modules may be distributed and deployed in different ECUs of the vehicle.

[0025] The execution unit 40 is communicatively connected to the control unit 30 to enable data interaction, and is configured to execute the control strategy generated by the control unit 30. The execution unit 40 may include an actuator of the vehicle power system for executing the target drive torque determined by the control unit 30. The execution unit 40 may also include an actuator of the vehicle braking system for executing the target brake torque determined by the control unit 30.

[0026] An embodiment of another aspect of the present invention relates to a vehicle steering control method applicable to providing seamless control during the activation or deactivation of a steering assist function. Although the seamless control method for the function activation process and the seamless control method for the function deactivation process have similar implementations, for a clearer description of the technical details, the control methods for the function activation and deactivation processes will be described in detail below. It should be understood that the steering control method of the embodiments of the present invention includes the control methods for the function activation and / or function deactivation processes, that is, the steering control method of the embodiments of the invention includes the control methods 300 and / or 400 to be introduced below.

[0027] Figure 3 Schematically shows a steering control method 300 for a vehicle according to an embodiment of the present invention. The method 300 is used to perform imperceptible control in response to a function activation signal. The method 300 can be executed by the above control unit 30.

[0028] See Figure 3 , at block 302, the control unit 30 receives a function activation signal. The above description of the function activation signal also applies here. In one embodiment, when the steering wheel angle requested by the driver or the driving assistance system exceeds a preset steering wheel angle and the current vehicle speed is within a preset vehicle speed range allowing activation of the steering assistance function, the system 100 will issue a function activation signal S_a to activate the steering assistance function. Here, both the preset steering wheel angle and the preset vehicle speed range are preset based on real vehicle test results and / or model simulation results.

[0029] At block 304, in response to receiving the function activation signal, the control unit 30 determines a target driving torque based on the target braking torque of the vehicle and the driving torque requested by the driver, so that through the coordination between the target driving torque and the target braking torque, during the activation process of the steering assistance function, the ride comfort of the vehicle reaches a level where the driver is unaware of the activation of the steering assistance function.

[0030] The target braking torque is generated by the steering assistance function and is used to assist in achieving the target steering behavior of the vehicle, which includes a target turning radius and a target steering angle. Both the target turning radius and the target steering angle can be set by the driver or the driving assistance system of the vehicle. The present invention does not limit the specific implementation manner of generating the target braking torque.

[0031] The activation process of the steering assistance function refers to the process of switching the function from the standby state to the activation state, which corresponds to the process of gradually increasing the target braking torque from an initial value (zero or the current value) to a preset value.

[0032] In one embodiment, the ride comfort of the vehicle reaches a level where the driver is unaware of the activation of the steering assistance function, which is reflected as the vehicle speed change being less than a vehicle speed change threshold. This threshold is a small value calibrated in advance to restrict the amplitude of the vehicle speed fluctuation and ensure that the vehicle speed remains stable, for example, without large fluctuations or jumps.

[0033] In another embodiment, the ride comfort of the vehicle reaches a level where the driver is unaware of the activation of the steering assistance function, which is reflected as the acceleration change of the vehicle being less than an acceleration change threshold. This threshold is a small value calibrated in advance to restrict the amplitude of the acceleration fluctuation and ensure the smoothness of the vehicle acceleration process, for example, uniform acceleration or acceleration with a small slope.

[0034] Next, the specific implementation of the box 304 will be introduced.

[0035] In one implementation, at box 3041, the control unit 30 obtains the current vehicle speed and the target braking torque. The current vehicle speed can be obtained from the sensor unit 10. For the target braking torque, please refer to the relevant description above.

[0036] At box 3042, the control unit 30 obtains the steering wheel angle requested by the driver. The steering wheel angle requested by the driver can be calculated by the sensor unit 10 detecting the steering force applied by the driver to the steering wheel and based on the mapping relationship between the steering force and the steering wheel angle. For example, the sensor unit 10 collects the steering force data applied by the driver in real time, combines the dynamic model of the vehicle steering system and the preset force-angle conversion algorithm to deduce the corresponding steering wheel angle value.

[0037] At box 3043, the control unit 30 determines the value of the first adjustment coefficient based on the current vehicle speed and the steering wheel angle requested by the driver. The value of the first adjustment coefficient is negatively correlated with the vehicle speed and positively correlated with the steering wheel angle requested by the driver.

[0038] In one embodiment, a two-dimensional look-up table for determining the first adjustment coefficient is pre-stored in the control unit 30. This table records the values of the first adjustment coefficient corresponding to different combinations of multiple vehicle speed ranges and multiple steering wheel angle ranges. The following Table 1 shows an example of such a two-dimensional look-up table. In Table 1, the first row represents the steering wheel angle requested by the driver, increasing from left to right, and each value corresponds to a steering wheel angle range. The first column represents the current vehicle speed, increasing from top to bottom, and each value corresponds to a vehicle speed range. Through this structured data storage method, the control unit 30 can quickly find the value of the first adjustment coefficient that matches the current vehicle speed and the steering wheel angle. It should be understood that the values in Table 1 are all exemplary and are not used to limit the present invention in any way.

[0039] Table 1

[0040] 0 5 10 15 1 0.6 0.7 0.8 0.9 2 0.55 0.65 0.75 0.85 3 0.5 0.6 0.7 0.8 4 0.45 0.55 0.65 0.75

[0041] In another embodiment, two one-dimensional look-up tables are pre-stored in the control unit 30 for determining the value of the first adjustment coefficient. The first one-dimensional look-up table contains multiple first values of the first adjustment coefficient, each value corresponding to a different vehicle speed range, and the first values are negatively correlated with the vehicle speed (i.e., the higher the vehicle speed, the smaller the first value). The second one-dimensional look-up table contains multiple second values of the first adjustment coefficient, each value corresponding to a different steering wheel angle range, and the second values are positively correlated with the steering wheel angle (i.e., the larger the steering wheel angle, the larger the second value). According to the current vehicle speed and the steering wheel angle requested by the driver, the control unit 30 retrieves the corresponding first value and second value from these two one-dimensional look-up tables respectively, and multiplies the two to obtain the value of the first adjustment coefficient.

[0042] At block 3044, the control unit 30 calculates a first drive torque adjustment amount based on the target braking torque and the value of the first adjustment coefficient. For example, the control unit 30 multiplies the target braking torque by the value of the first adjustment coefficient to obtain the first drive torque adjustment amount. This approach is beneficial. For example, since the value of the first adjustment coefficient is negatively correlated with the vehicle speed (i.e., the higher the vehicle speed, the smaller the value of the first adjustment coefficient), the first drive torque adjustment amount will decrease as the vehicle speed increases. This helps to avoid the risk of vehicle instability caused by excessive drive torque during high-speed driving, thus enhancing driving safety. On the other hand, since the value of the first adjustment coefficient is positively correlated with the steering wheel angle (i.e., the larger the steering wheel angle, the larger the value of the first adjustment coefficient), the first drive torque adjustment amount will increase as the steering wheel angle increases. Because an increase in the steering wheel angle means an increase in steering resistance, and at this time the vehicle speed will decrease. By increasing the drive torque, the influence of the steering resistance can be compensated, ensuring the power output and handling stability of the vehicle during the steering process.

[0043] At block 3045, the control unit 30 determines the target drive torque based on the drive torque requested by the driver and the first drive torque adjustment amount. For example, the control unit 30 adds the drive torque requested by the driver to the first drive torque adjustment amount to obtain the target drive torque. The drive torque requested by the driver can be obtained from the force applied by the driver on the accelerator pedal detected by the sensor unit 10. For example, based on a preset pedal force-drive torque mapping relationship (such as through a look-up table or a mathematical model), the pedal force is converted into the corresponding drive torque requested by the driver.

[0044] The target driving torque obtained in the above manner can not only accurately reflect the driver's intention, but also dynamically adjust the first driving torque adjustment amount in combination with the target braking torque, the current vehicle speed, and the steering wheel angle requested by the driver. This design optimizes the power output of the vehicle during the steering process, thereby enhancing the smoothness during the activation of the steering assist function. Specifically, the dynamic adjustment of the increase in the first driving torque ensures a more reasonable power output of the vehicle under different vehicle speeds and steering conditions, avoiding the risk of instability during high-speed driving and enhancing the power response during low-speed steering. This coordinated control strategy makes the activation process of the steering assist function smoother, providing a more natural and comfortable driving experience for the driver.

[0045] In block 306, the control unit 30 transmits the determined target driving torque to the execution unit 40 so that the execution unit 40 controls the vehicle power system according to the target driving torque, thereby ensuring that the driving torque output by the power system (Engine torque) is consistent with the target driving torque.

[0046] Figure 4 Schematically shows a steering control method 400 for a vehicle according to an embodiment of the present invention. The method 400 is used to perform seamless control in response to a function exit signal. The method 400 can be executed by the above-mentioned control unit 30.

[0047] See Figure 4 , in block 402, the control unit 30 receives the function exit signal S_de. The above description of the function exit signal also applies here.

[0048] In block 404, after receiving the function deactivation signal, the control unit 30 determines the target driving torque based on the target braking torque of the vehicle and the driving torque requested by the driver, so that through the coordination between the target driving torque and the target braking torque, during the exit process of the steering assist function, the smoothness of the vehicle reaches a level where the driver is unaware of the activation of the steering assist function. The above description of the target braking torque also applies here.

[0049] The exit process of the steering assist function refers to the process in which the function switches from the activated state to the fading state and then switches to the standby state after a predetermined duration of the fading state. This process corresponds to the process in which the target braking torque gradually decreases from the current value (e.g., the above preset value) to zero. The predetermined duration of the fading state can be determined according to whether the steering assist function exits in the normal mode or the emergency mode.

[0050] When at least one of the following is detected, it is determined that the steering assist function exits in the emergency mode; when none of the following is detected, it is determined that the steering assist function exits in the normal mode: 1) The emergency braking function (AEB) of the vehicle is triggered; 2) The pedal force of the driver stepping on the brake pedal exceeds the brake pedal force threshold (this situation means that the driver expects the vehicle to stop or idle, thus no longer meeting the preset vehicle speed range for the steering assist function); 3) The yaw rate of the vehicle exceeds the yaw rate threshold (this situation means that the driving state of the vehicle is unstable and no longer meets the activation conditions of the steering assist function).

[0051] According to an embodiment of the present invention, the preset duration of the fade-out state includes a first preset duration when the steering assist function exits in the normal mode and a second preset duration when the steering assist function exits in the emergency mode.

[0052] When the steering assist function exits in the normal mode, the first preset duration of the fade-out state (i.e., the duration of the fade-out state) is determined according to the decreasing slope of the target braking torque (i.e., the unloading rate). Specifically, the greater the unloading rate of the target braking torque, the shorter the first preset duration of the fade-out state; conversely, the smaller the unloading rate, the longer the first preset duration of the fade-out state. The unloading slope of the target braking torque is generated by the steering assist function according to the target steering behavior (for example, the target turning radius and the target steering angle during the function exit process). The present invention does not limit the specific generation method of the unloading slope of the braking torque.

[0053] When the steering assist function exits in the emergency mode, the second preset duration of the fade-out state is determined according to the maximum pressure relief rate of the vehicle braking system. The maximum pressure relief rate is determined according to the maximum pressure relief capacity of the pressure relief valve of the braking system and needs to meet the maximum noise level allowed during the pressure relief process.

[0054] The above embodiments regarding the ride comfort of the vehicle reaching the level where the driver is unaware of the activation of the steering assist function are equally applicable here.

[0055] Next, the specific implementation of block 404 will be introduced.

[0056] In one embodiment, the control unit 30 acquires the current vehicle speed and the target braking torque of the vehicle. The current vehicle speed can be obtained from the sensor unit 10. For the target braking torque, please refer to the above relevant description.

[0057] In block 4042, the control unit 30 acquires the steering wheel angle requested by the driver. For the steering wheel angle requested by the driver, please refer to the above relevant description.

[0058] In block 4043, the control unit 30 determines a second adjustment coefficient based on the current vehicle speed and the steering wheel angle requested by the driver. Similar to the value of the first adjustment coefficient, the value of the second adjustment coefficient is also negatively correlated with the vehicle speed and is also positively correlated with the steering wheel angle requested by the driver.

[0059] According to an embodiment of the present invention, the value of the second adjustment coefficient can also be determined using the above two-dimensional look-up table or two one-dimensional look-up tables. However, the corresponding relationship in which the value of the second adjustment coefficient is negatively correlated with the vehicle speed and positively correlated with the steering wheel angle may be different from the corresponding relationship in which the value of the first adjustment coefficient is negatively correlated with the vehicle speed and positively correlated with the steering wheel angle. In other words, although both the second adjustment coefficient and the first adjustment coefficient adopt a similar look-up table structure, their corresponding relationships may be different. For example, when the vehicle speed is lower than a predetermined low speed, the second adjustment coefficient decreases faster relative to the first adjustment coefficient; when the steering wheel angle is greater than a predetermined steering wheel angle, the second adjustment coefficient increases faster relative to the first adjustment coefficient.

[0060] In this way, the second adjustment coefficient can be dynamically adjusted according to the vehicle speed and the steering wheel angle requested by the driver and remain independent of the first adjustment coefficient, so as to meet different control requirements.

[0061] In block 4044, the control unit 30 calculates a second driving torque adjustment amount based on the target braking torque and the value of the second adjustment coefficient. For example, the control unit 30 multiplies the target braking torque by the value of the second adjustment coefficient to obtain the second driving torque adjustment amount. The above related descriptions regarding the advantages of this approach also apply here.

[0062] In block 4045, the control unit 30 determines the target driving torque based on the driving torque requested by the driver and the second driving torque adjustment amount. For example, the control unit 30 adds the driving torque requested by the driver to the second driving torque adjustment amount to obtain the target driving torque. The above related descriptions regarding the advantages of this approach also apply here.

[0063] In addition, according to an embodiment of the present invention, the target braking torque becomes zero when the target braking torque function exits. At this time, the control unit 30 determines the target driving torque as the value corresponding to the driving torque requested by the driver and ensures that the deviation between the two is less than the tolerance threshold. This tolerance threshold changes dynamically with the driving torque requested by the driver at this time. For example, this tolerance threshold is equal to a predetermined percentage of the driving torque requested by the driver. In this way, while ensuring the response accuracy of the driving torque, a necessary system adjustment margin is provided.

[0064] In addition, according to an embodiment of the present invention, when the vehicle is four-wheel drive and adopts a main rear-wheel drive configuration, after receiving a function activation signal, the control unit 30 will adjust the drive torque distribution between the front and rear axles to transfer at least part of the drive torque on the vehicle's rear axle to the vehicle's front axle. After receiving a function exit signal, the control unit 30 will adjust the drive torque distribution between the front and rear axles again to transfer at least part of the drive torque on the vehicle's front axle back to the vehicle's rear axle.

[0065] In block 306, the control unit 30 transmits the determined target drive torque to the execution unit 40 so that the execution unit 40 controls the vehicle power system according to the target drive torque, thereby ensuring that the drive torque (Engine torque) output by the power system is consistent with the target drive torque.

[0066] According to an embodiment of the present invention, there is also provided a machine-readable storage medium storing executable instructions, which when executed by one or more processors cause the one or more processors to execute the steering control methods 300 and / or 400 as described above.

[0067] According to an embodiment of the present invention, there is also provided a computer program product including instructions which, when executed by one or more processors, cause the one or more processors to execute the steering control methods 300 and / or 400 as described above. It should be noted that all operations in the methods described above are merely exemplary. The present invention is not limited to any operation in the methods or the order of these operations, but should cover all other equivalent transformations under the same or similar concepts.

[0068] It should be noted that the processor can use any combination of one or more of the following: a suitable central processing unit, CPU, multi-processor, single-chip microcomputer, digital signal processor, DSP, application-specific integrated circuit, etc., which can execute the software instructions of the computer program stored in the memory. Therefore, the memory can be considered as part of the computer program product or form part of the computer program product. The processor can be configured to execute the computer program stored therein to enable the controller to perform the required steps.

[0069] It should be noted that software should be widely regarded as representing instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, running threads, processes, functions, etc. Software can reside in a computer-readable medium. The computer-readable medium can include, for example, a memory, and the memory can be, for example, a magnetic storage device (such as a hard disk, a floppy disk, a magnetic stripe), an optical disk, a smart card, a flash memory device, a random access memory (RAM), a read-only memory (ROM), a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), a register, or a removable disk. Although the memory is shown as being separate from the processor in many aspects given in this disclosure, the memory can also be located inside the processor (such as a cache or a register).

[0070] The above description is provided to enable any person skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein. All structural and functional equivalent transformations of the elements of the various aspects described in this disclosure that are known or will be known to those skilled in the art will be expressly incorporated herein by reference and are intended to be covered by the claims.

Claims

1. A steering control method for a vehicle, comprising: In response to a function activation signal or a function exit signal of a steering assist function of the vehicle, a target driving torque is determined based on a driving torque requested by a driver of the vehicle and a target braking torque, so that during the activation or exit process of the steering assist function, a vehicle speed change is less than a vehicle speed change threshold or an acceleration change is less than an acceleration change threshold, so that the ride comfort of the vehicle reaches a level at which the driver does not perceive the activation or exit of the steering assist function; The target braking torque is generated by a steering assist function to assist the vehicle in achieving a target turning radius and / or a target steering angle.

2. The steering control method according to claim 1, wherein: The activation process of the steering assist function includes the process of the function from the standby state to the active state, wherein when the function activation signal is detected, the steering assist function switches from the standby state to the active state; The exit process of the steering assist function includes the process of the function changing from an activated state to a fade-out state and then to a standby state, wherein when a function exit signal is detected, the steering assist function switches from an activated state to a fade-out state, and after a predetermined period of time in the fade-out state, switches to the standby state.

3. The steering control method according to claim 2, wherein: The predetermined duration of the gradually retreating state includes a first predetermined duration when the steering assist function is exited in a normal mode and a second predetermined duration when the steering assist function is exited in an emergency mode; The steering assist function exits in emergency mode when at least one of the following is detected: - The vehicle's automatic emergency braking (AEB) function is triggered; - The driver's brake pedal force exceeds the brake pedal force threshold; -The vehicle's yaw rate exceeds a yaw rate threshold.

4. The steering control method according to claim 1, wherein: Determining the target driving torque includes: After receiving the function activation signal, determining a first adjustment coefficient based on the current vehicle speed and the steering wheel angle requested by the driver; determining a first driving torque adjustment amount based on the target braking torque and a first adjustment coefficient; and The target driving torque is determined as a sum of the driving torque requested by the driver and the first driving torque adjustment amount.

5. The steering control method according to claim 4, wherein: The value of the first adjustment coefficient is negatively correlated with the current vehicle speed and positively correlated with the steering wheel angle requested by the driver; and The first driving torque adjustment amount is equal to the product of the target braking torque and the first adjustment coefficient.

6. The steering control method according to claim 1, wherein: Determining the target driving torque includes: After receiving the function exit signal, determining a second adjustment coefficient based on the current vehicle speed and the steering wheel angle requested by the driver; determining a second driving torque adjustment amount based on the target braking torque and the second adjustment coefficient; and The target driving torque is determined as a sum of the driving torque requested by the driver and the second driving torque adjustment amount.

7. The steering control method according to claim 6, wherein: The value of the second adjustment coefficient is negatively correlated with the current vehicle speed and positively correlated with the steering wheel angle requested by the driver; and The second driving torque adjustment amount is equal to the product of the target braking torque and the second adjustment coefficient.

8. The steering control method according to claim 1, wherein: The target braking torque gradually increases to a preset value during function activation, and gradually decreases from the preset value to zero during function exit; and When the steering assist function is exited, the target driving torque corresponds to the driving torque requested by the driver, and a difference between the target driving torque and the driving torque requested by the driver is less than a predetermined percentage of the driving torque requested by the driver.

9. The steering control method according to claim 1, wherein: When the vehicle is a four-wheel drive and is mainly rear-wheel drive: After receiving the function activation signal, adjusting the driving torque distribution between the front and rear axles so that at least part of the driving torque on the rear axle is transferred to the front axle; as well as After receiving the function exit signal, the driving torque distribution between the front and rear axles is adjusted so that at least part of the driving torque on the front axle is transferred to the rear axle.

10. A control unit for controlling vehicle steering, comprising a memory and one or more processors, wherein the memory stores instructions, which when executed by the one or more processors enable the one or more processors to implement the method according to any one of claims 1 to 9.

11. A computer-readable storage medium storing executable instructions, wherein when the instructions are executed, one or more processors execute the method according to any one of claims 1 to 9.

12. A computer program product comprising instructions which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 1 to 9.

Images