Vehicle motion control system, steering assist unit, and steering assist method

Abstract

Aspects of the invention provide a vehicle motion control system, a steering assist unit, and a steering assist method. According to an embodiment of the invention, the steering assistance method of the vehicle comprises the following steps: transmitting a minimum turning radius which can be provided by a steering assistance function to a driving assistance control unit of the vehicle; receiving a steering assistance request including a target turning radius from a driving assistance control unit; vehicle braking pressure corresponding to the target turning radius is determined through a vehicle turning model; determining whether an actual turning radius after the vehicle executes the determined brake pressure matches a target turning radius; if it is judged that the actual turning radius is not matched with the target turning radius, according to the difference value of the actual turning radius relative to the target turning radius, closed-loop control is adopted to calculate the determined adjusting value of the brake pressure; and if it is judged that the actual turning radius is matched with the target turning radius, the determined brake pressure is kept unchanged.

Description

Technical Field

[0001] The present invention relates to a steering assist unit and a steering assist method for a vehicle, and also relates to a vehicle motion control system comprising the steering assist unit. Background Art

[0002] When a vehicle performs a driving assistance function, it often involves the vehicle steering process. The driving assistance function may fail to exit due to various problems in the vehicle steering process. For example, the vehicle cannot turn the desired angle in a confined space, the vehicle's turning radius is too large to avoid collision with environmental obstacles, etc. For such problems, there is no better solution in the prior art. Summary of the invention

[0003] In this context, the present invention aims to provide a solution capable of timely calling the vehicle steering assist function.

[0004] According to an embodiment of one aspect of the present invention, a steering assist method for a vehicle is provided, comprising: sending a minimum turning radius that can be provided by a steering assist function to a driving assist control unit of the vehicle; receiving a steering assist request including a target turning radius from the driving assist control unit; determining a vehicle braking pressure corresponding to the target turning radius using a vehicle turning model; determining whether an actual turning radius after the vehicle executes the determined braking pressure matches the target turning radius; if it is determined that the actual turning radius does not match the target turning radius, calculating an adjustment value of the braking pressure determined based on the difference between the actual turning radius and the target turning radius and using closed-loop control, the braking pressure adjusted by the adjustment value can make the actual turning radius of the vehicle match the target turning radius; and if it is determined that the actual turning radius matches the target turning radius, keeping the determined braking pressure unchanged.

[0005] According to an embodiment of another aspect of the present invention, a steering assist method for a vehicle is provided, comprising: sending a minimum turning radius that a steering assist function can provide to a driving assist control unit of the vehicle; receiving a steering assist request including a target turning radius from the driving assist control unit; determining a vehicle braking pressure corresponding to the target turning radius using a vehicle turning model; determining a driving force based on a current throttle opening and the determined braking pressure; judging whether an actual turning radius after the vehicle executes the determined braking pressure and driving force matches the target turning radius; if it is determined that the actual turning radius does not match the target turning radius, calculating a brake pressure adjustment value determined based on a difference between the actual turning radius and the target turning radius and using closed-loop control, the brake pressure adjusted by the adjustment value can make the actual turning radius of the vehicle match the target turning radius; and if it is determined that the actual turning radius matches the target turning radius, keeping the determined braking pressure unchanged.

[0006] According to an embodiment of yet another aspect of the present invention, a vehicle motion control system is provided, which includes: a driving assistance control unit, configured to generate a steering assistance request including a target turning radius according to environmental conditions and vehicle driving conditions; the steering assistance unit as described above, configured to determine a corresponding vehicle braking pressure according to the target turning radius; and an execution unit, configured to execute the determined vehicle braking pressure.

[0007] According to an embodiment of still another aspect of the present invention, a vehicle is provided, which includes the steering assist unit as described above or the vehicle motion control system as described above.

[0008] According to an embodiment of still another aspect of the present invention, a computer program product is provided, which includes computer executable instructions, and when the instructions are executed, one or more processors are caused to perform the steering assist method as described above.

[0009] A summary of the main aspects of the present invention is provided above so that these aspects can be basically understood. This summary is not intended to describe the key or important elements of all aspects of the present invention, nor is it intended to limit the scope of any or all aspects of the present invention. The purpose of this summary is to provide some implementations of these aspects in a simplified form as a preface to the detailed description that will be provided later. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The technical solution of the present invention will become clearer from the following detailed description in conjunction with the accompanying drawings. It is understood that these drawings are only used for exemplary description and are not intended to limit the scope of protection of the present invention.

[0011] Figure 1 is a schematic block diagram of a vehicle motion control system according to an embodiment of the present invention.

[0012] Figure 2 is a flow chart of a steering assist method for a vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION

[0013] The inventors found that the steering assist function in the prior art is usually triggered only when the driver actively operates the function switch. This may lead to the problem that the steering assist function cannot be triggered in time. In view of this, the embodiments of the present invention propose a solution that can trigger the vehicle steering assist function in time without the driver's active operation. As a result, during the startup and execution of the steering assist function, the driver can maintain a "senseless" driving experience, thereby achieving a smoother and seamless integration of assisted driving technology.

[0014] The steering assistance solution according to the embodiment of the present invention can be combined with many driving assistance functions of the vehicle, thereby expanding the application scenarios of these driving assistance functions. For example, when the steering assistance solution according to the embodiment of the present invention is applied to the automatic parking function, obstacles in narrow parking spaces can be avoided in time, thereby improving parking efficiency and success rate.

[0015] The solution according to the embodiment of the present invention can be applied to the driver driving mode and the assisted driving mode, that is, it is applicable to human driving and intelligent driving. It is worth noting that in the embodiment of the present invention, "driving assistance" should be understood to include various levels of driving assistance, for example, semi-automatic driving and fully automatic driving.

[0016] The steering assist solution according to the embodiment of the present invention does not require any changes to the vehicle hardware and has the advantage of being cost-effective.

[0017] The specific implementation of the present invention is described below in conjunction with the accompanying drawings.

[0018] Figure 1 A vehicle motion control system 100 according to an embodiment of the present invention is shown, which includes a driving assistance control unit 10 , a steering assistance unit 20 , an execution unit 30 , and a human-machine interface 40 .

[0019] The driving assistance control unit 10 is implemented as: a control unit (ADASECU) of a driving assistance system (not shown) of a vehicle; or, included in the control unit of the driving assistance system as a submodule of the control unit of the driving assistance system. When the driving assistance control unit 10 determines that the vehicle needs to turn with a turning radius smaller than the current turning radius, it generates a steering assistance request including a target turning radius (i.e., a turning radius smaller than the current turning radius) to request the steering assistance unit 20 to perform a steering assistance function so that the vehicle can turn with the target turning radius.

[0020] The steering assist unit 20 is in communication with the driving assist control unit 10, and is used to determine the corresponding vehicle brake pressure according to the requested target turning radius, that is, the brake pressure that assists the vehicle to achieve the target turning radius. In addition, the steering assist unit can use a closed-loop control algorithm to calculate the adjustment value of the brake pressure to ensure that the executed brake pressure can enable the vehicle to turn at the requested target turning radius.

[0021] In one embodiment, the steering assist unit 20 can be implemented in hardware or software or a combination of software and hardware. For the part implemented in hardware, it can be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, electronic units designed to perform their functions, or combinations thereof. For the part implemented in software, it can be implemented with the aid of microcodes, program codes, or code segments, and they can also be stored in machine-readable storage media such as storage components.

[0022] In one embodiment, the steering assist unit 20 can be arranged in an electronic control unit (ECU) of the vehicle, or in a vehicle body control unit (VCU) of the vehicle, or in a domain controller of the vehicle. In addition, the steering assist unit 20 can be divided into a plurality of submodules according to functions, and these submodules can be arranged in a plurality of ECUs of the vehicle or a part of them can be arranged in an ECU and another part can be arranged in a VCU or a domain controller.

[0023] In one embodiment, the steering assist unit 20 may be implemented as including a memory and a processor. The memory contains executable instructions, which, when executed by the processor, enable the processor to perform the steering assist method according to the embodiment of the present invention.

[0024] The execution unit 30 is in communication with the steering assist unit 20 and is used to execute the braking pressure determined by the steering assist unit 20 or adjust the executed braking pressure with the braking pressure adjustment value determined by the steering assist unit. In addition, in some embodiments, the execution unit 30 is also used to execute the driving force determined by the steering assist unit 20.

[0025] The human-machine interface 40 is used to implement interaction between the vehicle and the vehicle driver. The human-machine interface 40 may include multiple interfaces for implementing human-machine interaction in multiple ways, such as a voice control interface, a touch screen, and operable physical controls (e.g., knobs or buttons). According to an embodiment of the present invention, the vehicle driver can obtain the current steering state information of the vehicle through the human-machine interface 40.

[0026] Figure 2A steering assist method 200 according to an embodiment of the present invention is shown. The method 200 may be performed by the vehicle motion control system 100, and for clarity, the method 200 is depicted in the form of a swim lane diagram. It should be understood that the operations involved in the following method 200 do not need to be performed in the exact order described. Instead, they may be performed in a different order, or multiple operations may be processed simultaneously, and operations may be added or omitted.

[0027] See also Figure 2 In block 202, the steering assist unit 20 determines whether an activation condition of the steering assist function is satisfied. The activation condition of the steering assist function is preset in consideration of the safety and reliability of running the function.

[0028] In one embodiment, the activation condition of the steering assist function includes multiple conditions, for example, condition 1 and condition 2 to be described below. When all conditions are met, the steering assist unit 20 determines that the activation condition of the steering assist function is met. When at least one condition is not met, the steering assist unit 20 determines that the activation condition of the steering assist function is not met.

[0029] Condition 1: The requested value of the steering wheel steering angle is equal to or close to the angle value of the steering wheel being turned fully to the left or right. "Close to" refers to an angle value that is greater than a predetermined percentage of the angle value of the steering wheel being turned fully to the left or right. The predetermined percentage should be a large percentage close to 1, for example, 95% or 98%. According to an embodiment of the present invention, in the driver driving mode, the request for the steering wheel steering angle may be issued by the vehicle driver, for example, the requested value of the steering wheel steering angle is derived based on the driver force applied by the driver to the steering wheel. In the driving assistance mode, the requested value of the steering wheel steering angle may be issued by the driving assistance system.

[0030] Condition 2: There are no abnormalities in the software and hardware related to the steering assist function. For example, the relevant software includes programs related to controlling the operation of the steering assist system. These programs are used to receive sensor input, process data, make decisions, and control actuators (for example, execution unit 30) to achieve assisted steering. The relevant hardware includes sensors, controllers, actuators, and connecting lines between them for implementing the steering assist function. The present invention does not limit how to detect whether there are abnormalities in these software and hardware.

[0031] If the determination result of block 202 is that the activation condition of the steering assist function is not satisfied, the method 200 returns to block 202 to continue determining whether the activation condition of the steering assist function is satisfied.

[0032] If the judgment result of frame 202 is that the activation condition of the steering assist function is satisfied, the method 200 enters frame 204 .

[0033] In box 204, the steering assist unit 20 sends the minimum turning radius of the vehicle that the steering assist function can provide to the driving assist control unit 10. According to an embodiment of the present invention, the steering assist function can assist the vehicle to turn with a smaller (reduced) turning radius relative to the current turning radius. The minimum turning radius that the steering assist function can provide is pre-set. The present invention does not limit how to determine the minimum turning radius.

[0034] At block 206 , the driving assistance control unit 10 receives from the steering assistance unit 20 the minimum turning radius of the vehicle that the steering assist function can provide.

[0035] In box 208, the driving assistance control unit 10 generates a steering assistance request. The steering assistance request includes a requested target turning radius. The target turning radius may include a target value of the turning radius and / or a target reduction relative to the current turning radius (i.e., the difference between the current turning radius and the target turning radius). The steering assistance request may also include road surface condition information of the road on which the vehicle is traveling. The road surface condition information may include one or more of the following: 1) road surface type (e.g., asphalt, ice and snow, sand, grass, etc.); 2) road surface adhesion coefficient.

[0036] Next, one implementation of block 208 is described.

[0037] In one embodiment, in box 2081, the driving assistance control unit 10 determines whether the vehicle needs to turn with a smaller (reduced) turning radius relative to the current turning radius. For example, the driving assistance control unit 10 can calculate the current turning radius of the vehicle and determine that the vehicle needs to turn with a smaller turning radius when at least one of the following situations occurs: 1) The current turning radius is too large to cause the vehicle to be unable to complete the driving assistance function being run, for example, due to narrow space or irregular drivable space, the vehicle cannot automatically park in the target parking space with the current turning radius; 2) A collision event will occur during the process of the vehicle turning with the current turning radius, for example, the vehicle will collide with a stationary obstacle or a moving object in the environment.

[0038] It is worth noting that the driving assistance control unit 10 can calculate the current turning radius of the vehicle in a variety of ways. The present invention does not limit the specific way of calculating the current turning radius of the vehicle, but focuses more on the requested target turning radius.

[0039] In block 2082, when it is determined that the vehicle needs to turn with a smaller turning radius, the driving assistance control unit 10 calculates a target turning radius, that is, a target value of the turning radius (for example, the current turning radius is 30 meters, and the target turning radius is 20 meters) or a target reduction amount (for example, the target reduction amount is 10 meters, that is, the current turning radius is reduced by 10 meters). In general, the target value or target reduction amount of the turning radius can enable the vehicle to avoid stationary obstacles or moving objects in the environment, or pass through a narrow space smoothly, or successfully reach the target position.

[0040] Next, some implementations of the computing block 2082 are introduced.

[0041] In one embodiment, the driving assistance control unit 10 predicts the vehicle's driving trajectory based on the vehicle's current turning radius, and calculates the maximum overlap distance between the driving trajectory and the stationary obstacles in the environment. The maximum overlap distance is the target reduction in the turning radius; or, the target reduction in the turning radius is a value slightly larger than the maximum overlap distance. The stationary obstacles are, for example, curbs, temporary roadblocks, etc.

[0042] In another embodiment, the driving assistance control unit 10 predicts the vehicle's driving trajectory based on the vehicle's current turning radius, predicts the moving trajectory of the moving object based on the current moving state and moving trend of the moving object in the environment, and calculates the intersection position between the vehicle's driving trajectory and the moving trajectory of the moving object. The driving assistance control unit 10 determines the target reduction amount of the turning radius based on the intersection position so that the vehicle's steering process can avoid collision with the moving object.

[0043] In another embodiment, the driving assistance control unit 10 calculates multiple target turning radii, that is, the requested target turning radius may include multiple target values ​​or multiple target reductions of the turning radius. The multiple target turning radii include at least a first target turning radius and a second target turning radius. The first target turning radius is a turning radius calculated in the above manner that enables the vehicle to avoid stationary obstacles or moving objects during the steering process. The second target turning radius is greater than the first target turning radius. After the vehicle turns with the first target turning radius and avoids stationary obstacles or moving objects in the environment, it turns with the second target turning radius. In this way, the vehicle's driving trajectory may include multiple arc paths, that is, an arc path turned with the first target turning radius and an arc path turned with the second target turning radius. The advantage of doing this is that it can reduce the loss of vehicle hardware, because turning a vehicle with a smaller (extremely small) turning radius will cause hardware loss, especially wheel wear.

[0044] In block 2083 , the driving assistance control unit 10 determines whether the calculated target turning radius is greater than or equal to the received minimum turning radius, that is, determines whether the steering assist function can achieve the target turning radius.

[0045] If the determination result is negative, that is, the calculated target turning radius is smaller than the received minimum turning radius, it means that the steering assist function is not capable of achieving such a small turning radius, and the method 200 ends.

[0046] If the determination result is positive, that is, the calculated target turning radius is greater than or equal to the received minimum turning radius, which means that the steering assist function is capable of achieving the target turning radius, the driving assist control unit 10 generates (block 2084) a steering assist request.

[0047] At block 210 , the driving assistance control unit 10 sends a steering assistance request to the steering assistance unit 20 .

[0048] At block 212 , the steering assist unit 20 receives a steering assist request from the driving assist control unit 10 .

[0049] In block 214 , the steering assist unit 20 determines the vehicle brake pressure corresponding to the requested target turning radius, that is, the brake pressure that needs to be applied to the vehicle in order to achieve the vehicle turning with the target turning radius.

[0050] In one embodiment, the steering assist unit 20 may use a vehicle turning model to determine the brake pressure corresponding to the target turning radius. The vehicle turning model may be implemented in one or more of the following ways: 1) a turning radius-brake pressure curve (for example, the horizontal axis represents the turning radius, the vertical axis represents the brake pressure, and the turning radius-brake pressure curve in this coordinate system represents the corresponding relationship between the turning radius and the brake pressure); 2) a table containing the corresponding relationship between multiple turning radii and multiple brake pressures; 3) a brake pressure function with the turning radius as the independent variable (for example, the target turning radius is substituted into the function, and the calculated function value is the brake pressure); 4) a machine learning model with the turning radius as the input and the brake pressure as the output (for example, the machine learning model is trained with a large amount of turning radius-brake pressure sample data, so that when a new turning radius is input, the corresponding brake pressure is output).

[0051] The vehicle turning model is predetermined and stored in the steering assist unit 20. In the case where the received steering assist request contains road condition information, such as road surface type and / or road surface adhesion coefficient, the steering assist unit 20 can correct the determined brake pressure according to the road surface condition information. For example, when the current road surface type is ice or the road surface adhesion coefficient is low, the determined brake pressure is appropriately reduced to reduce the risk of wheel slippage. In general, in order to improve the safety and stability of vehicle driving when correcting the brake pressure based on the road surface type or the road surface adhesion coefficient, the present invention does not limit the specific implementation method of correcting the brake pressure.

[0052] In block 216 , the steering assist unit 20 sends the determined vehicle brake pressure to the actuator unit 30 so that the actuator unit 30 executes the brake pressure. In the case where the brake pressure is corrected, the steering assist unit 20 sends the corrected brake pressure to the actuator unit 30 .

[0053] In block 218 , the steering assist unit 20 determines whether the actual turning radius after the braking pressure is applied matches the requested target turning radius. The driving assist control unit 10 may monitor the actual turning radius of the vehicle in real time and send the monitored actual turning radius to the steering assist unit 20 .

[0054] In one embodiment, the steering assist unit 20 determines whether the actual turning radius matches the requested target turning radius with a predetermined error margin. Specifically, when the difference between the actual turning radius and the target turning radius is greater than the error margin, it is determined that the actual turning radius does not match the requested target turning radius. When the difference between the actual turning radius and the target turning radius is less than or equal to the error margin, it is determined that the actual turning radius matches the requested target turning radius.

[0055] The error margin is predetermined and stored in the steering assist unit 20. The steering assist unit 20 can adjust the error margin. Furthermore, the steering assist unit 20 can adjust the control accuracy of the steering assist function for the turning radius by adjusting the error margin. Specifically, when it is desired to improve the control accuracy, the error margin is reduced; when it is desired to improve the fault tolerance and redundancy of the system, the error margin is increased.

[0056] If the answer to the determination in block 218 is yes, ie, the actual turning radius matches the requested target turning radius, the method 200 proceeds to block 220 .

[0057] In block 220 , the steering assist unit 20 determines to keep the current brake pressure unchanged.

[0058] If the answer to the determination in block 218 is negative, ie, the actual turning radius does not match the requested target turning radius, the method 200 proceeds to block 222 .

[0059] In box 222, the steering assist unit 20 uses closed-loop control to calculate the determined brake pressure adjustment value so that the execution unit 30 adjusts the executed brake pressure with the adjustment value. Adjusting the brake pressure by the adjustment value can make the actual turning radius of the vehicle match the requested target turning radius.

[0060] Next, one implementation of block 222 is described.

[0061] In one embodiment, the steering assist unit 20 obtains the adjustment value of the brake pressure by adopting a feedback controller. For example, the steering assist unit 20 calculates the difference between the actual turning radius and the target turning radius, and inputs the difference into the feedback controller. The feedback controller can calculate the brake pressure adjustment value by a first adjustment value and a second adjustment value. The first adjustment value is obtained, for example, by multiplying the input difference by a proportional gain. The function of the first adjustment value is to quickly respond to the system deviation (i.e., the difference between the actual turning radius and the target turning radius) so that the system approaches the target value (i.e., the target turning radius) as soon as possible. The second adjustment value includes an initial value and a cumulative step length, the initial value is set according to the braking force at the wheel end, and the step length is obtained by multiplying the input difference by an integral gain. The main function of the second adjustment value is to eliminate the static error of the system, that is, to eliminate the residual deviation.

[0062] According to an embodiment of the present invention, the vehicle motion control system 100 can store brake pressure adjustment values ​​and use these brake pressure adjustment values ​​to periodically update (optimize) the vehicle turning model. Through such a mechanism, the vehicle turning model can more accurately calculate the required vehicle brake pressure according to the target turning radius, thereby improving the accuracy and reliability of turning control.

[0063] According to an embodiment of the present invention, after determining the vehicle braking pressure, the steering assist unit 20 can distribute the determined braking pressure as the front axle braking pressure and / or the rear axle braking pressure based on the following three factors: 1) the vehicle's drive configuration (e.g., front-wheel drive, rear-wheel drive, four-wheel drive); 2) the magnitude of the driving force on the front and rear axles; and 3) suspension characteristic parameters (e.g., the height and stiffness of the suspension, whether the suspension is an active suspension or a semi-active suspension).

[0064] In one embodiment, if it is a front-wheel drive vehicle, the braking pressure is preferentially distributed to the rear axle; if it is a rear-wheel drive vehicle, the braking pressure is preferentially distributed to the front axle; if it is a four-wheel drive vehicle, it can be determined first whether to use the main front drive or the main rear drive (for example, determined by the vehicle user or by the driving assistance control unit 10), and then distributed according to the above-mentioned front drive or rear drive logic.

[0065] In addition, according to some embodiments of the present invention, after determining the vehicle braking force corresponding to the requested target turning radius, the steering assist unit 20 can also determine the driving force based on the current accelerator pedal opening and the determined vehicle braking pressure, so that part of the driving force is used to respond to the current accelerator pedal opening requirement; the other part is used to compensate for the insufficient steering power that may occur after braking, thereby ensuring the stability and safety of the vehicle turning process.

[0066] After determining the driving force, the steering assist unit 20 sends the determined driving force to the execution unit 30 so that the execution unit 30 controls the driving system of the vehicle to execute the driving force.

[0067] The steering assist unit 20 can determine the driving force in the following manner. The steering assist unit 20 determines a first driving force corresponding to the current accelerator pedal opening. The present invention does not limit the specific manner of determining the first driving force corresponding to the current accelerator pedal opening. The steering assist unit 20 determines a second driving force related to the vehicle braking force, which is numerically close to or equal to the determined braking force, for example, the second driving force is numerically equal to the determined vehicle braking force plus or minus a predetermined adjustment amount. The predetermined adjustment amount should be a smaller value so that the compensation amount for the driving force is substantially equal to the determined braking pressure. The steering assist unit 20 calculates the sum of the first and second driving forces to obtain the driving force.

[0068] The embodiment of the present invention further provides a vehicle, which includes the above-mentioned steering assist unit 20 or the above-mentioned vehicle motion control system 100. The above-mentioned features and advantages of the steering assist unit 20 or the above-mentioned vehicle motion control system 100 are also applicable here.

[0069] An embodiment of the present invention further provides a computer program product, which includes computer executable instructions. When the instructions are executed, one or more processors are caused to perform the steering assist method as described above.

[0070] An embodiment of the present invention further provides a machine-readable storage medium storing executable instructions, which, when executed, enable one or more processors to perform the steering assist method as described above.

[0071] A computer program product includes computer executable instructions, which when executed cause one or more processors to perform the method 300 described above.

[0072] It should be noted that the processor may use any combination of one or more of the following: an appropriate central processing unit, CPU, multiprocessor, single-chip microcomputer, digital signal processor, DSP, application-specific integrated circuit, etc., capable of executing software instructions of a computer program stored in the memory. Therefore, the memory may be considered as part of or forming part of a computer program product. The processor may be configured to execute a computer program stored therein to cause the controller to perform the required steps.

[0073] It should be noted that software should be broadly considered to represent instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software modules, applications, software applications, software packages, routines, subroutines, objects, running threads, processes, functions, etc. The software may reside in a computer-readable medium. The computer-readable medium may include, for example, a memory, which may be, for example, a magnetic storage device (e.g., 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 the various aspects provided in the present disclosure, the memory may also be located inside the processor (e.g., a cache or a register).

[0074] 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 are apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein. All structural and functional equivalents of elements of various aspects described in this disclosure that are known or to be known to those skilled in the art will be expressly included herein by reference and are intended to be covered by the claims.

Claims

1. A steering assist method for a vehicle, comprising: Sending the vehicle's driver assistance control unit the minimum turning radius that the steering assist function can provide; receiving a steering assistance request including a target turning radius from a driving assistance control unit; The vehicle turning model is used to determine the vehicle braking pressure corresponding to the target turning radius; determining whether an actual turning radius of the vehicle after the determined braking pressure is applied matches a target turning radius; If it is determined that the actual turning radius does not match the target turning radius, a brake pressure adjustment value determined by closed-loop control calculation is used based on a difference between the actual turning radius and the target turning radius, and the brake pressure adjusted by the adjustment value can make the actual turning radius of the vehicle match the target turning radius; as well as If it is determined that the actual turning radius matches the target turning radius, the determined brake pressure is maintained unchanged.

2. A steering assist method for a vehicle, comprising: Sending the vehicle's driver assistance control unit the minimum turning radius that the steering assist function can provide; receiving a steering assistance request including a target turning radius from a driving assistance control unit; The vehicle turning model is used to determine the vehicle braking pressure corresponding to the target turning radius; Determine the driving force according to the current throttle opening and the determined brake pressure; determining whether an actual turning radius after the vehicle has executed the determined braking pressure and driving force matches a target turning radius; If it is determined that the actual turning radius does not match the target turning radius, a brake pressure adjustment value determined by closed-loop control calculation is used based on a difference between the actual turning radius and the target turning radius, and the brake pressure adjusted by the adjustment value can make the actual turning radius of the vehicle match the target turning radius; as well as If it is determined that the actual turning radius matches the target turning radius, the determined brake pressure is maintained unchanged.

3. The steering assist method according to claim 2, wherein: Determining the driving force based on the current throttle opening and the determined brake pressure includes: determining a first driving force corresponding to a current accelerator pedal opening; determining a second actuation force that is equal to or close in value to the determined brake pressure; and The sum of the first and second driving forces is determined as the driving force.

4. The steering assist method according to any one of claims 1 to 3, wherein: The target turning radius includes a target value of the turning radius and / or a reduction amount relative to the current turning radius.

5. The steering assist method according to any one of claims 1 to 3, wherein: The target turning radius is related to at least one of the following: -The maximum overlap distance between the driving trajectory and the stationary obstacles in the environment predicted based on the vehicle's current turning radius; - The intersection position between the driving trajectory predicted based on the current turning radius of the vehicle and the predicted motion trajectory of the moving object in the environment.

6. The steering assist method according to claim 5, wherein: The target turning radius includes multiple target turning radii, and the multiple target turning radii include at least: - a first target turning radius for enabling the vehicle to avoid the stationary obstacle or the moving object; and - A second turning radius for reaching a target position in a rotational manner after the vehicle has avoided the stationary obstacle or the moving object.

7. The steering assist method according to any one of claims 1 to 3, wherein: The vehicle turning model includes one or more of the following: - Turning radius-brake pressure curve; - a table containing correspondences between a plurality of turning radii and a plurality of brake pressures; - Braking pressure function with turning radius as independent variable; -A machine learning model that takes turning radius as input and brake pressure as output.

8. The steering assist method according to any one of claims 1 to 3, wherein: Determining whether the actual turning radius matches the target turning radius includes: Whether the actual turning radius matches the target turning radius is determined with a predetermined error margin, wherein the predetermined error margin is adjustable.

9. The steering assist method according to any one of claims 1 to 3, wherein: The steering assist request also includes road condition information of the road on which the vehicle is traveling, and the road condition information optionally includes a road adhesion coefficient, and Determining the vehicle braking pressure includes: correcting the vehicle braking pressure determined by using a vehicle turning model according to road condition information.

10. The steering assist method according to any one of claims 1 to 3, comprising: Distributing the determined vehicle brake pressure into front axle brake pressure and / or rear axle brake pressure according to the vehicle's drive configuration, current drive forces of the front and rear axles, and suspension characteristic parameters; and The distributed front axle brake pressure and / or rear axle brake pressure is sent to an actuator unit of the vehicle in order to execute the distributed front axle brake pressure and / or rear axle brake pressure.

11. The steering assist method according to any one of claims 1 to 3, comprising: Determining whether an activation condition of the steering assist function is met; as well as When it is determined that the activation condition is satisfied, sending the minimum turning radius of the vehicle to a driving assistance control unit of the vehicle; When all of the following conditions are met, it is determined that the activation condition of the steering assist function is met, and when at least one of the conditions is not met, it is determined that the activation condition of the steering assist function is not met: -The requested value of the steering wheel steering angle is equal to or close to the angle value of the steering wheel being turned fully left or fully right; -There are no anomalies in the software and hardware related to the steering assist function.

12. A steering assist unit for a vehicle, comprising one or more processors configured to execute the steering assist method according to any one of claims 1-11.

13. A vehicle motion control system, comprising: a driving assistance control unit configured to generate a steering assistance request including a target turning radius according to environmental conditions and vehicle driving conditions; The steering assist unit according to claim 12, configured to determine a corresponding vehicle brake pressure according to a target turning radius; as well as The execution unit is configured to execute the determined vehicle brake pressure.

14. The vehicle motion control system of claim 13, wherein: The driving assistance control unit monitors the actual turning radius of the vehicle in real time and sends the monitored actual turning radius to the steering assistance unit; The steering assist unit determines whether the actual turning radius matches the target turning radius. If it is determined that the actual turning radius does not match the target turning radius, the closed-loop control is used to calculate the determined adjustment value of the brake pressure according to the difference between the actual turning radius and the target turning radius, so that the execution unit adjusts the brake pressure of the vehicle with the adjustment value. If it is determined that the actual turning radius matches the target turning radius, the determined brake pressure is kept unchanged. as well as After the actuator has adjusted the brake pressure using the adjustment value, the actual turning radius of the vehicle can be adapted to the target turning radius.

15. The vehicle motion control system of claim 13, wherein: When the environmental conditions and / or the vehicle driving conditions change, the driving assistance control unit generates a new steering assistance request including a new target turning radius; The steering assist unit determines a corresponding new vehicle brake pressure according to the new target turning radius; and The actuating unit is configured to actuate a new vehicle brake pressure.

16. A vehicle comprising the steering assist unit according to claim 9 or the vehicle motion control system according to any one of claims 13-15.

17. A computer program product comprising computer executable instructions, which when executed cause one or more processors to perform the steering assistance method according to any one of claims 1-11.

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