Steering assistance control method and apparatus, and vehicle

Abstract

A steering assistance control method (1200) and apparatus, and a vehicle (100). The steering assistance control method (1200) comprises: acquiring a first planned path and speed information of a vehicle (100), the first planned path being used by the vehicle (100) to avoid a first obstacle (S1210); upon determining, on the basis of the first planned path, that the vehicle (100) is in an obstacle avoidance phase, separately determining a desired front wheel rotation angle and a desired rear wheel rotation angle on the basis of a curvature and a position indicated by the first planned path, and the speed information; or, upon determining, on the basis of the first planned path, that the vehicle (100) is in a return-to-center phase, determining a desired front wheel rotation angle and a desired rear wheel rotation angle on the basis of a front wheel rotation angle and the speed information of the vehicle (100) (S1220); and controlling the vehicle (100) to implement the desired front wheel rotation angle and the desired rear wheel rotation angle (S1230). The method (1200) can improve the steering capability of the vehicle (100) in an emergency situation and broaden the capability limits of active safety of the vehicle (100), thereby improving the reliability and safety of the vehicle (100).

Description

Steering assist control methods, devices and vehicles Technical Field

[0001] This application relates to the field of intelligent driving, and more specifically, to a steering assist control method, device, and vehicle. Background Technology

[0002] As vehicles become increasingly intelligent and automated, more and more vehicles are equipped with intelligent driving systems, such as Advanced Driving Assistant Systems (ADAS), to reduce driving stress and improve safety. ADAS systems include numerous active safety functions, such as Automatic Emergency Braking (AEB), Lane Departure Warning (LDW), Emergency Lane Keeping Assist (ELKA), Evasive Steering Assist (ESA), and Automatic Emergency Steering (AES), which enhance driving safety. In emergency situations, these active safety functions can proactively assess and preventatively implement safety measures before the driver's subjective reaction. ADAS systems also include many driver assistance functions, such as Lane Centering Control (LCC) and Adaptive Cruise Control (ACC), which can reduce driving stress and alleviate driver fatigue.

[0003] However, current ADAS systems all have limitations in handling emergency obstacle avoidance situations. For example, with AEB (Autonomous Emergency Braking), at high speeds, if the vehicle's braking distance is insufficient, AEB may be unable to bring the vehicle to a stop in time to avoid a collision. When the braking distance is insufficient, the driver may attempt to avoid the obstacle by steering. However, this steering may result in understeer, leading to obstacle avoidance failure; or it may result in oversteer, causing the vehicle to lose control.

[0004] Therefore, a safer and more reliable steering assist control scheme urgently needs to be developed. Summary of the Invention

[0005] This application provides a steering assist control method, device, and vehicle that can improve the vehicle's steering ability in emergency situations, broaden the boundaries of the vehicle's active safety capabilities, and thereby improve the vehicle's reliability and safety.

[0006] In a first aspect, a steering assist control method is provided, which can be executed by a vehicle; or, it can also be executed by a vehicle's computing platform; or, it can also be executed by a chip or circuit for the vehicle, without limitation thereof.

[0007] The method includes: acquiring a first planned path and vehicle speed information, the first planned path being used by the vehicle to avoid a first obstacle; when the vehicle is determined to be in the obstacle avoidance phase according to the first planned path, determining the desired front wheel steering angle and the desired rear wheel steering angle according to the curvature and position indicated by the first planned path and the speed information, respectively; or, when the vehicle is determined to be in the straightening phase according to the first planned path, determining the desired front wheel steering angle and the desired rear wheel steering angle according to the vehicle's front wheel steering angle and speed information; and controlling the vehicle to execute the desired front wheel steering angle and the desired rear wheel steering angle.

[0008] The obstacle avoidance phase refers to the stage where a vehicle changes lanes from its original lane to another lane to avoid an obstacle. During lane changing, the angle between the vehicle's longitudinal axis and the lane line will be relatively large. Therefore, the straightening phase refers to the stage where the vehicle body is straightened until the angle between the vehicle's longitudinal axis and the lane line is less than or equal to a certain angle threshold. For example, the aforementioned angle threshold can be a value between 3° and 5°, or it can be any other value.

[0009] In the aforementioned technical solution, when a vehicle needs to avoid an obstacle, the rear-wheel steering capability of the vehicle is considered. The front and rear wheels are simultaneously steered to avoid the obstacle, enabling obstacle avoidance even when the distance between the vehicle and the obstacle is relatively short, thus improving the vehicle's active safety capabilities. Furthermore, compared to controlling the vehicle to avoid obstacles solely through the front wheels, controlling both the front and rear wheels simultaneously reduces the steering wheel rotation angle required during obstacle avoidance. In human-driven or human-machine co-driving situations, this reduces the difficulty of the driver taking over the vehicle, thereby improving the driving experience. In addition, based on different stages of the vehicle's obstacle avoidance process, the desired front and rear wheel steering angles are determined according to various factors. During the obstacle avoidance phase, the vehicle follows a planned trajectory to avoid the obstacle ahead; during the straightening phase, vehicle stability is ensured, preventing the vehicle from veering off the lane, thus improving vehicle safety and reliability.

[0010] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: obtaining the lateral position and heading angle of the vehicle; determining the lateral error and heading angle error respectively based on the first planned path, the lateral position, and the heading angle, wherein the lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path; determining the desired steering angle of the front wheels and the desired steering angle of the rear wheels respectively, including: determining the desired steering angle feedforward based on the curvature and speed information of the first planned path, wherein the desired steering angle feedforward includes the front wheel steering angle feedforward and the rear wheel steering angle feedforward; determining the desired steering angle feedback based on the lateral error and the heading angle error, wherein the desired steering angle feedback includes the front wheel steering angle feedback and the rear wheel steering angle feedback; and determining the desired steering angle of the front wheels and the desired steering angle of the rear wheels respectively based on the desired steering angle feedforward and the desired steering angle feedback.

[0011] In the above technical solution, rear-wheel steering-assisted obstacle avoidance can quickly establish yaw and lateral displacement gains. Furthermore, based on the curvature of the planned path and the vehicle's speed, the desired steering angle feedforward is determined. Based on the vehicle's actual heading angle and lateral position, the desired steering angle feedforward is adjusted to obtain the final desired steering angle. This helps improve the fit between the vehicle's actual driving path and the planned path, enabling the vehicle to quickly avoid obstacles along the planned obstacle avoidance path, preventing understeer or oversteer, and enhancing the vehicle's overall obstacle avoidance capabilities.

[0012] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: determining the tire lateral force feedforward amount based on the curvature and speed information of the first planned path; determining the tire lateral force feedback amount based on the lateral error and the heading angle error, wherein the lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path; determining the tire desired lateral force based on the tire lateral force feedforward amount and the tire lateral force feedback amount, wherein the tire desired lateral force includes the front wheel desired lateral force and the rear wheel desired lateral force; and determining the front wheel desired steering angle and the rear wheel desired steering angle respectively, including: determining the front wheel desired steering angle and the rear wheel desired steering angle respectively based on the tire desired lateral force.

[0013] In the above technical solution, the feedforward and feedback quantities of the tire lateral force are determined respectively, and then the tire's expected steering angle is determined based on the expected lateral force of the tire. This helps to improve the fit between the actual driving path and the planned path of the vehicle, so that the vehicle can quickly avoid obstacles along the planned obstacle avoidance path.

[0014] In conjunction with the first aspect, in some implementations of the first aspect, when it is determined that the vehicle is in the straightening phase according to the first planned path, the desired front wheel angle and the desired rear wheel angle are determined based on the vehicle's front wheel angle and speed information, including: determining the desired yaw rate based on the vehicle's front wheel angle and speed; determining the desired front wheel angle based on the vehicle's actual yaw rate and desired yaw rate; and determining the desired rear wheel angle based on the desired front wheel angle.

[0015] In the above technical solution, during the return-to-center phase, the front wheel angle of the vehicle is determined based on the vehicle's yaw rate and speed, and then the rear wheel angle is determined based on the front wheel angle. On the one hand, this can ensure the stability of the vehicle during the return-to-center process, reduce the risk of vehicle instability under extreme obstacle avoidance conditions, stabilize the vehicle's attitude, and improve the safety of emergency obstacle avoidance functions; on the other hand, it helps to reduce the complexity and computational load in the process of determining the desired wheel angle.

[0016] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: acquiring obstacle information, motion state information, and steering capability information, wherein the obstacle information indicates at least one obstacle that hinders the vehicle's movement, the at least one obstacle that hinders the vehicle's movement includes a first obstacle, the motion state information indicates the vehicle's position, speed, and heading angle, and the steering capability information indicates the maximum steering angle of the vehicle's front wheels and the maximum steering angle of the vehicle's rear wheels; determining the vehicle's maximum obstacle avoidance capability based on the motion state information and the steering capability information; and acquiring a first planned path, including: acquiring the first planned path when the vehicle can avoid the first obstacle under the maximum obstacle avoidance capability.

[0017] In some implementations, the angular velocity of the front wheels and the angular velocity of the rear wheels of a vehicle can be predicted based on the maximum steering angle of the front wheels and the maximum steering angle of the rear wheels.

[0018] In some other implementations, steering capability information also indicates the angular velocity of the vehicle's front wheels and the angular velocity of the vehicle's rear wheels.

[0019] In the above technical solution, determining the vehicle's obstacle avoidance capability based on its rear-wheel steering ability helps to broaden the operational range of the vehicle's active safety. Furthermore, when the vehicle can avoid the first obstacle under its maximum obstacle avoidance capability, obtaining a first planned path and controlling the vehicle to avoid the obstacle along that first planned path helps reduce the risk of collision. When the vehicle cannot avoid the first obstacle under its maximum obstacle avoidance capability, suppressing the activation of the steering assist function helps reduce the probability of vehicle instability during steering and avoids more serious accidents.

[0020] In conjunction with the first aspect, in some implementations of the first aspect, the maximum obstacle avoidance capability indicator is the maximum lateral displacement that the vehicle can achieve within a first distance by controlling the steering angles of the front and rear wheels of the vehicle, where the first distance is the distance between the vehicle and the first obstacle at the current moment.

[0021] In conjunction with the first aspect, in some implementations of the first aspect, the method further includes: determining the front wheel avoidance capability of the vehicle based on motion state information and the maximum front wheel steering angle, wherein the front wheel avoidance capability indicates the maximum lateral displacement that the vehicle can achieve within a second distance by controlling the front wheel steering angle, the second distance being the distance between the vehicle and the first obstacle at the current moment; determining the maximum avoidance capability of the vehicle includes: determining the maximum avoidance capability of the vehicle when the vehicle cannot avoid the first obstacle under the front wheel avoidance capability, or when the front wheel steering angle required to avoid the first obstacle is greater than a steering angle threshold and / or the lateral acceleration required to avoid the first obstacle is greater than or equal to an acceleration threshold.

[0022] In the aforementioned technical solutions, when a vehicle is unable to avoid an obstacle based on its front wheel avoidance capability, controlling the front and rear wheels to steer simultaneously to avoid the obstacle helps to improve the vehicle's active safety operating range. Alternatively, when the wheel angle required for front wheel avoidance is too large or the lateral acceleration is too large, controlling the front and rear wheels to steer simultaneously to avoid the obstacle helps to reduce the steering wheel angle required during the avoidance phase.

[0023] In conjunction with the first aspect, in some implementations of the first aspect, determining the vehicle's maximum avoidance capability includes: determining the vehicle's maximum avoidance capability when the time to collision (TTC) is less than or equal to a duration threshold.

[0024] In the above technical solution, determining whether to steer the vehicle's front and rear wheels simultaneously to avoid obstacles by using the collision time helps simplify the judgment logic in the process of activating the steering assist function and reduces computational complexity.

[0025] In a second aspect, a steering assist control device is provided, comprising an acquisition unit and a processing unit, wherein the acquisition unit is configured to: acquire a first planned path and vehicle speed information, the first planned path being used by the vehicle to avoid a first obstacle; the processing unit is configured to: when the vehicle is determined to be in an obstacle avoidance phase according to the first planned path, determine the desired front wheel steering angle and the desired rear wheel steering angle respectively according to the curvature and position indicated by the first planned path and the speed information; or, when the vehicle is determined to be in a straightening phase according to the first planned path, determine the desired front wheel steering angle and the desired rear wheel steering angle according to the vehicle's front wheel steering angle and speed information; the processing unit is further configured to: control the vehicle to execute the desired front wheel steering angle and the desired rear wheel steering angle.

[0026] In conjunction with the second aspect, in some implementations of the second aspect, the acquisition unit is further configured to: acquire the lateral position and heading angle of the vehicle; the processing unit is configured to: determine the lateral error and heading angle error based on the first planned path, the lateral position, and the heading angle, respectively, wherein the lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path; determine the desired steering angle feedforward based on the curvature and speed information of the first planned path, wherein the desired steering angle feedforward includes the front wheel steering angle feedforward and the rear wheel steering angle feedforward; determine the desired steering angle feedback based on the lateral error and the heading angle error, wherein the desired steering angle feedback includes the front wheel steering angle feedback and the rear wheel steering angle feedback; and determine the desired steering angle of the front wheels and the desired steering angle of the rear wheels based on the desired steering angle feedforward and the desired steering angle feedback, respectively.

[0027] In conjunction with the second aspect, in some implementations of the second aspect, the processing unit is used to: determine the tire lateral force feedforward amount based on the curvature and speed information of the first planned path; determine the tire lateral force feedback amount based on the lateral error and the heading angle error, wherein the lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path; determine the tire desired lateral force based on the tire lateral force feedforward amount and the tire lateral force feedback amount, wherein the tire desired lateral force includes the front wheel desired lateral force and the rear wheel desired lateral force; and determine the front wheel desired steering angle and the rear wheel desired steering angle based on the tire desired lateral force.

[0028] In conjunction with the second aspect, in some implementations of the second aspect, the processing unit is used to: determine the desired yaw rate based on the front wheel steering angle and the vehicle speed; determine the desired front wheel steering angle based on the actual yaw rate and the desired yaw rate; and determine the desired rear wheel steering angle based on the desired front wheel steering angle.

[0029] In conjunction with the second aspect, in some implementations of the second aspect, the acquisition unit is further configured to: acquire obstacle information, motion state information, and steering capability information, wherein the obstacle information indicates at least one obstacle that obstructs the vehicle's movement, and the at least one obstacle that obstructs the vehicle's movement includes a first obstacle; the motion state information indicates the vehicle's position, speed, and heading angle; and the steering capability information indicates the maximum steering angle of the vehicle's front wheels and the maximum steering angle of the vehicle's rear wheels; the processing unit is configured to: determine the vehicle's maximum avoidance capability based on the motion state information and the steering capability information; and the acquisition unit is configured to: acquire a first planned path when the vehicle can avoid the first obstacle under the maximum avoidance capability.

[0030] In conjunction with the second aspect, in some implementations of the second aspect, the maximum obstacle avoidance capability indicator is the maximum lateral displacement that the vehicle can achieve within a first distance by controlling the steering angles of the front and rear wheels of the vehicle, where the first distance is the distance between the vehicle and the first obstacle at the current moment.

[0031] In conjunction with the second aspect, in some implementations of the second aspect, the processing unit is further configured to: determine the front wheel avoidance capability of the vehicle based on motion state information and the maximum front wheel steering angle, wherein the front wheel avoidance capability indicates the maximum lateral displacement that the vehicle can achieve within a second distance by controlling the front wheel steering angle, the second distance being the distance between the vehicle and the first obstacle at the current moment; and determine the maximum avoidance capability of the vehicle when the vehicle cannot avoid the first obstacle under the front wheel avoidance capability, or when the front wheel steering angle required to avoid the first obstacle is greater than a steering angle threshold and / or the lateral acceleration required to avoid the first obstacle is greater than or equal to an acceleration threshold.

[0032] In conjunction with the second aspect, in some implementations of the second aspect, the processing unit is used to: determine the vehicle's maximum avoidance capability when the TTC is less than or equal to the duration threshold.

[0033] Thirdly, a steering assist control device is provided, the device comprising: a processor for executing a computer program stored in the memory, such that the device performs the method in any possible implementation of the first aspect described above.

[0034] In conjunction with the third aspect, in some implementations of the third aspect, the device also includes a memory.

[0035] Fourthly, a computer program product is provided, comprising: computer program code, which, when executed on a computer or processor, causes the computer or processor to perform the method in any possible implementation of the first aspect.

[0036] It should be noted that the above computer program code can be stored in whole or in part on a storage medium, which can be packaged together with the processor or packaged separately from the processor.

[0037] Fifthly, a computer-readable storage medium is provided, the computer-readable medium storing instructions that, when executed by a processor, cause the processor to implement the method in any possible implementation of the first aspect.

[0038] In a sixth aspect, a chip is provided that includes circuitry for performing the method in any of the possible implementations of the first aspect described above.

[0039] In a seventh aspect, a vehicle is provided that includes means as in any possible implementation of the second or third aspect, or the vehicle includes a computer-readable storage medium as in any possible implementation of the fifth aspect, or the vehicle includes a chip as in any possible implementation of the sixth aspect, or the vehicle is loaded with a computer program product as in any possible implementation of the fourth aspect.

[0040] In conjunction with the seventh aspect, in some implementations of the seventh aspect, the vehicle is a vehicle in a broad sense, such as a means of transportation (e.g., commercial vehicles, passenger cars, motorcycles, flying cars, trains, etc.), industrial vehicles (e.g., forklifts, trailers, tractors, etc.), engineering vehicles (e.g., excavators, bulldozers, cranes, etc.), agricultural equipment (e.g., lawnmowers, harvesters, etc.), amusement equipment, toy vehicles, etc. In practical implementation, the vehicle can also be a road vehicle, a water vehicle, an air vehicle, industrial equipment, agricultural equipment, or other intelligent driving equipment such as entertainment equipment. Attached Figure Description

[0041] Figure 1 is a functional schematic block diagram of the vehicle provided in an embodiment of this application;

[0042] Figure 2 is a schematic block diagram of the steering assist control system architecture provided in an embodiment of this application;

[0043] Figure 3 is a schematic diagram of the control stage after partitioning provided in an embodiment of this application;

[0044] Figure 4 is another schematic diagram of the control stage after division provided in the embodiment of this application;

[0045] Figure 5 is a schematic flowchart of the steering assist control method provided in an embodiment of this application;

[0046] Figure 6 is a schematic diagram of the vehicle kinematics model provided in an embodiment of this application;

[0047] Figure 7 is a schematic diagram of the vehicle avoidance path provided in an embodiment of this application;

[0048] Figure 8 is a schematic diagram of the vehicle dynamics model provided in an embodiment of this application;

[0049] Figure 9 is a control logic diagram provided in an embodiment of this application;

[0050] Figure 10 is a schematic diagram of the relationship between the gain coefficient and vehicle speed provided in the embodiments of this application;

[0051] Figure 11 is another control logic diagram provided in an embodiment of this application;

[0052] Figure 12 is another schematic flowchart of the steering assist control method provided in the embodiments of this application;

[0053] Figure 13 is a schematic block diagram of the steering assist control device provided in an embodiment of this application;

[0054] Figure 14 is another schematic block diagram of the steering assist control device provided in the embodiments of this application. Detailed Implementation

[0055] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0056] Figure 1 is a functional block diagram of a vehicle provided in an embodiment of this application. As shown in Figure 1, the vehicle 100 may include a perception system 120 and a computing platform 150. The perception system 120 may include several sensors for sensing information about the environment surrounding the vehicle 100. For example, the perception system 120 may include a positioning system, which may be a Global Positioning System (GPS), a BeiDou system, or other positioning systems. As another example, the perception system 120 may also include one or more of the following: an inertial measurement unit (IMU), a lidar, a millimeter-wave radar, an ultrasonic radar, and a camera device.

[0057] Some or all of the functions of vehicle 100 can be controlled by computing platform 150. Computing platform 150 may include processors 151 to 15n. A processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction read and execute capabilities, such as a central processing unit (CPU), microprocessor, graphics processing unit (GPU) (which can be understood as a type of microprocessor), or digital signal processor (DSP). In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. These logical relationships are fixed or reconfigurable. For example, the processor may be a hardware circuit implemented using an application-specific integrated circuit (ASIC) or a programmable logic device (PLD), such as a field-programmable gate array (FPGA). In reconfigurable hardware circuits, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the process of the processor loading instructions to implement related functions. Furthermore, the processor can also be a hardware circuit designed for artificial intelligence, which can be understood as an ASIC, such as a neural network processing unit (NPU), tensor processing unit (TPU), deep learning processing unit (DPU), etc. In addition, the computing platform 150 may also include a memory for storing instructions. Some or all of the processors 151 to 15n can call the instructions in the memory to implement the corresponding functions.

[0058] The computing platform 150 can control the operation of the intelligent driving system, which may include an advanced driving assistance system (ADAS) and an autonomous driving system (ADS). The intelligent driving system utilizes various sensors on the vehicle (including but not limited to: LiDAR, millimeter-wave radar, cameras, ultrasonic sensors, GPS, and inertial measurement units) to acquire information from the vehicle's surroundings, and analyzes and processes this information to achieve functions such as obstacle perception, target recognition, vehicle localization, path planning, and driver monitoring / alerts, thereby improving the safety, automation, and comfort of driving the vehicle.

[0059] At different levels of autonomous driving (or intelligent driving levels, ranging from L0 to L5, totaling six levels), intelligent driving systems can achieve different levels of automated driving assistance based on artificial intelligence algorithms and information acquired by multiple sensors. These levels of autonomous driving are based on the classification standards of the Society of Automotive Engineers (SAE). Specifically, L0 is no automation; L1 is driver assistance; L2 is partial automation; L3 is conditional automation; L4 is high automation; and L5 is full automation. At levels L1 to L3, the task of monitoring road conditions and reacting is jointly completed by the driver and the system, requiring the driver to take over dynamic driving tasks. Levels L4 and L5 allow the driver to completely transform into a passenger. Currently, the functions that intelligent driving systems can achieve mainly include, but are not limited to: adaptive cruise control, automatic emergency braking, automatic parking, blind spot monitoring, forward cross-traffic alert / braking, rear cross-traffic alert / braking, forward collision warning, lane departure warning, lane keeping assist, rear collision warning, traffic sign recognition, traffic jam assist, and highway assist. It should be understood that the above-mentioned functions can have specific modes at different levels of autonomous driving (L0-L5). The higher the level of autonomous driving, the more intelligent the corresponding mode.

[0060] In this application, the perception system 120 can perceive the motion state of obstacles around the vehicle, and the computing platform 150 can determine whether to activate the rear-wheel-based emergency steering assist function based on the motion state of the obstacles and the motion state of the vehicle. If it is determined that the rear-wheel-based emergency steering assist function is activated, the rear wheel steering angle and front wheel steering angle of the vehicle can be determined according to the control stage of the vehicle, and the vehicle can be controlled to execute the aforementioned steering angles to avoid obstacles.

[0061] It is understood that ESA can provide additional torque to the steering wheel through the electronic power steering (EPS) system to control the vehicle and avoid obstacles when the driver inputs understeering. AES can actively control the vehicle's wheels to steer and avoid obstacles when the vehicle is in autonomous driving mode. The steering assist control scheme provided in this application embodiment can be regarded as an enhancement of the ESA and / or AES functions, or the steering assist control method provided in this application can be deployed as a new active safety function in the vehicle's computing platform.

[0062] The roles of the perception system 120 and the computing platform 150 in this application are explained in detail below with reference to Figure 2. Figure 2 shows a schematic block diagram of the steering assist control system architecture provided in an embodiment of this application. The system includes a perception module 210, a collision simulation module 220, a planning module 230, a control module 240, and an actuator 250. The perception module 210 may include one or more sensors from the perception system 120 shown in Figure 1. The collision simulation module 220, the planning module 230, and the control module 240 may each include one or more processors from the computing platform 150 shown in Figure 1. The actuator 250 may include the steering and braking control system in the vehicle 100.

[0063] Specifically, the perception module 210 is used to collect information about obstacles around the vehicle and send the obstacle-related information to the collision simulation module 220.

[0064] In some implementations, the collision simulation module 220 simulates the vehicle's maximum obstacle avoidance path based on obstacle information and vehicle motion state information. This maximum obstacle avoidance path can be a path simulated based on the vehicle's rear-wheel steering capability, allowing the vehicle to avoid obstacles with maximum steering capacity. If the vehicle travels along this maximum obstacle avoidance path and avoids collision with the obstacle, the rear-wheel-based emergency steering assist function is activated. Furthermore, the collision simulation module 220 sends the collision simulation results to the planning module 230, or determines an instruction to activate the rear-wheel-based emergency steering assist function.

[0065] When the rear-wheel-based emergency steering assist function needs to be activated, the planning module 230 plans an obstacle avoidance path based on the vehicle's motion status information and obstacle information, and sends the planned path to the control module 240. In some implementations, the planning module 230 may also send the maximum capability obstacle avoidance path to the control module 240.

[0066] The control module 240 may include a control phase division module 241 and a wheel angle calculation module 242. The control phase division module 231, based on the obstacle avoidance path, divides the control phase into an obstacle avoidance phase, a centering phase, and a lane keeping phase. As shown in Figure 3, to control the vehicle along the obstacle avoidance path, a counter-clockwise steering torque is applied to the vehicle at position ②. When the vehicle reaches position ③, to prevent it from leaving the target lane, a clockwise steering torque is applied until the angle between the vehicle's centerline and the road boundary line is less than or equal to an angle threshold (e.g., to position ④). After the angle between the vehicle's centerline and the road boundary line is less than or equal to the angle threshold, the vehicle can remain in the target lane. Referring to Figure 3, the control phase corresponding to positions ② to ③ can be classified as the obstacle avoidance phase, the control phase corresponding to positions ③ to ④ can be classified as the centering phase, and the phase from position ④ until the vehicle stabilizes can be classified as the lane keeping phase.

[0067] In some implementations, the aforementioned stages can also be divided based on the curvature of the obstacle avoidance path. For example, as shown in Figure 4, when the path curvature is zero, it indicates that the vehicle is traveling in a straight line (e.g., the steering wheel angle is zero). When the curvature is not zero, it indicates that the vehicle's steering wheel angle is not zero, meaning the vehicle is turning. Taking the obstacle avoidance requirement of bypassing the obstacle from the left side of the vehicle as an example, the stage where the path curvature is negative in the vehicle coordinate system can be classified as the obstacle avoidance stage, and the stage where the path curvature is positive in the vehicle coordinate system can be classified as the straightening stage. In other implementations, the obstacle avoidance stage and the straightening stage can also be divided in other ways.

[0068] After the control phase division module 231 divides the control phases, it can determine the current control phase of the vehicle based on the vehicle position obtained by the perception module 210, and send this control phase information to the wheel angle calculation module 242. The wheel angle calculation module 242 calculates the wheel angles according to the control phase the vehicle is in. When the vehicle is in the obstacle avoidance phase, the wheel angle control module 242 determines the expected rear wheel angle and the expected front wheel angle based on the obstacle avoidance path curvature, vehicle speed, vehicle heading angle error, and lateral error, so that the vehicle can avoid obstacles along the planned obstacle avoidance path. When the vehicle is in the straightening phase, the expected yaw rate of the vehicle is determined based on the actual front wheel angle and vehicle speed. Then, the expected front wheel angle is determined based on the difference between the expected yaw rate and the actual yaw rate of the vehicle. Finally, the expected rear wheel angle is determined based on the expected front wheel angle and the gain coefficient to ensure the vehicle's stability during the straightening phase.

[0069] Furthermore, the aforementioned desired turning angles are input into the actuator 250. When the actuator 250 executes the desired turning angle, the vehicle can achieve obstacle avoidance and / or straightening.

[0070] It should be understood that the above system is only an example, and in actual applications, modules in the above system may be added or removed according to actual needs. For example, the collision simulation module 220 and the planning module 230 can be merged into one module. As another example, the planning module 230 and the control module 240 can be merged into one module.

[0071] The system provided by the embodiments of this application has been described above. The steering assist control method provided by the embodiments of this application will be described in detail below.

[0072] Figure 5 shows a schematic flowchart of a steering assist control method provided in an embodiment of this application. The method can be executed by the vehicle 100 shown in Figure 1 or by the control module 240 shown in Figure 2. The method 500 includes some or all of the steps in S501 to S505.

[0073] S501 acquires obstacle information in the vehicle's direction of travel, vehicle motion status information, and vehicle steering ability information.

[0074] In some implementations, obstacle information may be information collected by one or more sensors in the aforementioned perception system 120. Exemplarily, obstacle information indicates the direction and speed of motion of each obstacle in at least one obstacle. Vehicle motion state information may indicate one or more of the vehicle's speed, heading angle, and position relative to obstacles; alternatively, motion state information may also indicate information such as changes in vehicle speed. Vehicle steering capability information may indicate the maximum steering angle of the vehicle's front and rear wheels; alternatively, steering capability information may also indicate the vehicle's maximum lateral acceleration, the maximum steering rate of the vehicle's front wheels, the maximum steering rate of the vehicle's rear wheels, etc.

[0075] S502, based on motion state information and steering capability information, deduces the vehicle's maximum obstacle avoidance path.

[0076] For example, based on motion state information and steering capability information, the vehicle's maximum obstacle avoidance path is deduced. Then, based on obstacle information, it is determined whether the vehicle can avoid obstacles when traveling along the maximum obstacle avoidance path.

[0077] In some implementations, the maximum obstacle avoidance path of the vehicle can be deduced based on one or more of the following methods (i) to (iii):

[0078] Method (1): The maximum obstacle avoidance path of the vehicle is derived based on the kinematic model of rear wheel steering. Taking the example that the two front wheels of the vehicle are driven by the same drive motor and the two rear wheels are driven by another drive motor, the kinematic model mainly considers the influence of rear wheel steering on the instantaneous steering center of the vehicle, and does not consider the influence of tire side slip. Specifically, when the rear wheels and front wheels are in opposite directions, compared with relying only on the two front wheels for steering control, the instantaneous rotation center of the vehicle moves closer to the center of gravity of the vehicle, and the turning radius of the vehicle decreases accordingly, so that a kinematic path with greater curvature can be achieved. For example, the instantaneous rotation center of the vehicle changes from point O1 to point O2 as shown in Figure 6, and the turning radius of the vehicle changes from R1 to R2, so that the curvature of the maximum obstacle avoidance path of the vehicle is greater than the curvature of the limit obstacle avoidance path relying only on front wheel steering. More specifically, when the front wheels and rear wheels are in opposite directions, the turning radius R2 of the vehicle satisfies the following formulas (1) and (2):

[0079] Where, δ r and δ f Let be the rear wheel steering angle and the front wheel steering angle, respectively; 'a' be the distance between the front wheel and the vehicle's center of gravity; 'b' be the distance between the rear wheel and the vehicle's center of gravity; and 'β' be the vehicle's slip angle, which is the angle between the vehicle's direction of travel and its longitudinal axis. Combining formulas (1) and (2), we can obtain the following formula (3):

[0080] Furthermore, the angular velocity ω of the vehicle satisfies the following formula (4):

[0081] By substituting the vehicle's speed *v*, front wheel steering angle, and rear wheel steering angle into the above formula, the vehicle's maximum obstacle avoidance capability (e.g., minimum turning radius) at speed *v* can be derived. Furthermore, based on this maximum obstacle avoidance capability, the vehicle's maximum obstacle avoidance path can be deduced. The front and rear wheel steering angles at different moments in the deduction can be determined based on the wheel steering angles at the previous moment, as well as the maximum angular velocities of the front and rear wheels, respectively. After the front and rear wheel steering angles reach their maximum values, the obstacle avoidance path can be further deduced based on these maximum angles.

[0082] Method (II): Calculate the vehicle's maximum lateral acceleration based on the maximum rear-wheel steering acceleration. For example, this is done by calculating the maximum rear-wheel steering angle and the maximum front-wheel steering angle, along with the vehicle's current speed (i.e., v). x0 and v y0 (Resultant velocity), determine the maximum lateral acceleration a that the vehicle can achieve. yFurthermore, the longitudinal and lateral displacements of the vehicle are decoupled. Based on the vehicle's speed, the time required for the vehicle to move from its current position to the obstacle's location is determined. The longitudinal displacement from the vehicle's current position to the obstacle's location can be represented by x as shown in Figure 7. f Then, the lateral displacement y of the vehicle is determined according to the following formula (5). f y f =∫∫a y dtdt. (5)

[0083] It is understandable that when the vehicle reaches the obstacle, the actual required lateral displacement is greater than the lateral displacement y. f If so, it is determined that the vehicle cannot avoid the obstacle along the maximum avoidance path.

[0084] Method (3): The maximum obstacle avoidance path of the vehicle is derived based on the dynamic model of rear-wheel steering. The vehicle dynamic model considers the influence of tire characteristics and tire forces on the dynamic response of the vehicle. Compared with vehicles that rely solely on front-wheel steering, vehicles based on rear-wheel steering can actively control the rear wheel angle to change the magnitude of the rear wheel lateral force, thereby adjusting the yaw and lateral response of the vehicle. For example, referring to Figure 8, the dynamic model involved in the embodiments of this application can satisfy the following formulas (6) to (10): ma y =F yr cosδ r +F yf cosδ f (6)

[0085] Among them, F yr and F yf The lateral force exerted by the ground on the rear wheel and the lateral force exerted by the ground on the front wheel, respectively, a y Let be the lateral acceleration at the vehicle's center of mass. Therefore, the force on the vehicle along the Y-axis of the vehicle coordinate system satisfies formula (6).

[0086] Furthermore, the vehicle's lateral acceleration a y Satisfying formula (7), a y It consists of the following two parts: the acceleration generated by the vehicle's lateral motion along the Y-axis of the vehicle coordinate system. and the centripetal acceleration generated by the vehicle's yaw motion. v x Let X be the component of the vehicle speed along the X-axis in the vehicle coordinate system. α represents the vehicle's yaw angle. f and α rThese are the slip angles of the front and rear wheels, respectively. The slip angle of each wheel is the wheel rotation angle minus the difference between the tire velocity direction and the angle between the vehicle's longitudinal axis (i.e., the X-axis of the vehicle coordinate system). The lateral force F yf and F yr The relationship between C and the sideslip angle satisfies formulas (8) and (9), respectively. Where, C αf and C αr These are the lateral stiffnesses of the front and rear wheels, respectively. Formula (10) is the torque balance equation of the vehicle about the Z-axis of the vehicle coordinate system, where I is the moment of inertia of the vehicle.

[0087] By rearranging formulas (6) to (10), we can obtain the following formula (11):

[0088] In some implementations, the front wheel angle and rear wheel angle at different times are input into formula (11), and the maximum yaw angle supported by the vehicle is used as a constraint to deduce the maximum lateral displacement of the vehicle within the TTC. The method for determining the front wheel angle and rear wheel angle at different times can be referred to the description in method (1), and will not be repeated here. When the actual required lateral displacement is greater than the aforementioned maximum lateral displacement, it is determined that the vehicle cannot avoid the obstacle along the maximum capability avoidance path. The maximum yaw angle can be the critical yaw angle. When the yaw angle of the vehicle is greater than this maximum yaw angle, instability will occur.

[0089] It should be noted that the aforementioned methods (i) to (iii) simplify the vehicle into a model where the two front wheels are driven by the same drive motor and the two rear wheels are driven by another drive motor. In actual implementation, if the vehicle is driven by three or four drive motors, a more complex model can be used to deduce the vehicle's maximum obstacle avoidance path based on the vehicle's rear wheel steering capability.

[0090] S503 determines whether the vehicle can avoid obstacles when traveling on the maximum obstacle avoidance path.

[0091] Furthermore, S504 is executed when the vehicle can avoid obstacles by driving on the maximum capability obstacle avoidance path; otherwise, the rear-wheel steering assist function is not activated.

[0092] S504 determines the desired steering angles of the front and rear wheels of the vehicle based on the control phase in which the vehicle is located.

[0093] In some implementations, when the vehicle is in the obstacle avoidance phase, the lateral position and heading angle of the vehicle can be used as tracking targets to calculate the expected steering angles of the front and rear wheels.

[0094] In one example, as shown in Figure 9, the feedforward amount of the wheel lateral force is determined based on the curvature and vehicle speed of the planned obstacle avoidance path, including the front wheel lateral force feedforward amount F. yf_fw Rear wheel lateral force feedforward F yr_fw Based on the lateral error and heading angle error, determine the feedback amount of the wheel lateral force, including the front wheel lateral force feedback amount F. yf_fb Rear wheel lateral force feedforward F yr_fb Furthermore, the desired lateral force of the front wheels is determined based on the front wheel lateral force feedforward and feedback; the desired lateral force of the rear wheels is determined based on the rear wheel lateral force feedforward and feedback. By inputting the desired lateral forces of the front and rear wheels into the tire inverse model, the desired steering angles of the front and rear wheels of the vehicle can be obtained. For example, the tire inverse model may include the model defined by the aforementioned formulas (8) and (9).

[0095] In another example, the feedforward amount of the wheel turning angle can be determined based on the curvature and vehicle speed of the planned obstacle avoidance path; the feedback amount of the wheel turning angle can be determined based on the lateral error and heading angle error; and then the desired turning angles of the front and rear wheels of the vehicle can be determined based on the feedforward amount of the wheel turning angle and the feedback amount of the vehicle turning angle.

[0096] It should be noted that the planned obstacle avoidance path can be the aforementioned maximum capability obstacle avoidance path, or the planned obstacle avoidance path can be a re-planned obstacle avoidance path based on the vehicle's motion state information and the obstacle information, and the curvature of the obstacle avoidance path can be gentler than the curvature of the maximum capability obstacle avoidance path.

[0097] In some implementations, the vehicle is more prone to instability during the return-to-center phase. Therefore, during this phase, the front and rear wheel steering angles can be determined based on the vehicle's yaw angle. Specifically, as shown in Figure 10, the desired yaw angle is determined based on the front wheel steering angle and the vehicle's real-time speed. Then, based on the desired and actual yaw angles, the desired front wheel steering angle that ensures vehicle stability and rapid return-to-center is determined. For example, when the desired yaw angle is greater than the actual yaw angle, and the difference between them exceeds a certain threshold, the front wheel steering angle can be increased to accelerate the vehicle's return-to-center speed; that is, in this case, the desired front wheel steering angle is greater than the actual front wheel steering angle. When the desired yaw angle is less than the actual yaw angle, or when the desired yaw angle is greater than the actual yaw angle, but the difference between them is less than the aforementioned threshold, the front wheel steering angle can be decreased; that is, in this case, the desired front wheel steering angle is less than the actual front wheel steering angle.

[0098] For example, the desired yaw angle φ of the vehicle can be determined according to the following formula (12):

[0099] Where v is the vehicle's longitudinal speed, θ is the front wheel steering angle, and L is the vehicle's wheelbase. c Let be the characteristic speed of the vehicle, where the characteristic speed refers to the speed at which the steady-state yaw rate gain of the vehicle reaches its maximum value.

[0100] Furthermore, after determining the desired front wheel steering angle, the desired rear wheel steering angle can be determined based on the gain coefficients of the rear wheel steering angle and the front wheel steering angle. For example, the product of the desired front wheel steering angle and the gain coefficient is the desired rear wheel steering angle.

[0101] In some implementations, during the simultaneous steering of the front and rear wheels, the sideslip angle β and yaw angle are... The following formula (13) needs to be satisfied:

[0102] To ensure vehicle stability, the sideslip angle β must satisfy β = 0. Furthermore, formula (13) can be transformed into the following formula (14):

[0103] Specifically, the change of gain coefficient K2 with vehicle speed is shown in Figure 11.

[0104] In some implementations, the desired steering angles of the front and rear wheels can be determined by combining the road surface adhesion coefficient of the road where the vehicle is located.

[0105] S505 controls the vehicle to execute the desired steering angles of the front and rear wheels.

[0106] In some implementations, before executing S502, it can be deduced whether obstacle avoidance can be successfully achieved when steering based solely on the steering capability of the front wheels. If obstacle avoidance is successful, the maximum capability obstacle avoidance path will not be deduced. If obstacle avoidance cannot be successfully achieved based solely on the steering capability of the front wheels, S503 will be executed.

[0107] In some implementations, when obstacle avoidance is successful based solely on the steering capability of the front wheels, the vehicle can be controlled to avoid obstacles while the front wheels are steering, without considering the steering capability of the rear wheels.

[0108] The steering assist control method provided in this application can improve the vehicle's steering ability in emergency situations, broaden the boundaries of the vehicle's active safety capabilities, and thus improve the vehicle's reliability and safety.

[0109] Figure 12 shows another schematic flowchart of the steering assist control method provided in this application embodiment. This method can be executed by the vehicle 100 shown in Figure 1, or it can be executed by the control module 240 shown in Figure 2. The method 1200 includes:

[0110] S1210, Obtain the first planned path and the vehicle's speed information. The first planned path is used for the vehicle to avoid the first obstacle.

[0111] For example, the first planned path can be the maximum capability obstacle avoidance path in method 500, or it can be an obstacle avoidance path planned based on the vehicle's position and speed, as well as the obstacle's position and speed.

[0112] In some implementations, the method further includes: acquiring obstacle information, motion state information, and steering capability information; the obstacle information indicates at least one obstacle that hinders the vehicle's movement, and the at least one obstacle hindering the vehicle's movement includes a first obstacle; the motion state information indicates the vehicle's position, speed, and heading angle; and the steering capability information indicates the maximum steering angle of the vehicle's front wheels and the maximum steering angle of the vehicle's rear wheels; and determining the vehicle's maximum obstacle avoidance capability based on the motion state information and steering capability information. S1210 can be refined to: acquiring a first planned path when the vehicle can avoid the first obstacle under the maximum obstacle avoidance capability.

[0113] The maximum obstacle avoidance capability indicator, by controlling the steering angles of the vehicle's front and rear wheels, allows the vehicle to achieve the maximum lateral displacement within a first distance, where the first distance is the distance between the vehicle and the first obstacle at the current moment. For example, the current moment can be the moment when the determination of the vehicle's maximum obstacle avoidance capability begins. For example, the vehicle's maximum obstacle avoidance capability can be characterized by the vehicle's maximum obstacle avoidance path. The specific implementation of the vehicle's maximum obstacle avoidance capability can be determined by referring to the description in S502, which will not be repeated here.

[0114] In some implementations, the method includes: determining the front wheel avoidance capability of the vehicle based on motion state information and the maximum front wheel steering angle, wherein the front wheel avoidance capability indicates the maximum lateral displacement that the vehicle can achieve within a second distance by controlling the front wheel steering angle, the second distance being the distance between the vehicle and the first obstacle at the current moment; determining the maximum avoidance capability of the vehicle includes: determining the maximum avoidance capability of the vehicle when it cannot avoid the first obstacle under the front wheel avoidance capability, or when the front wheel steering angle required to avoid the first obstacle is greater than a steering angle threshold and / or the lateral acceleration required to avoid the first obstacle is greater than or equal to an acceleration threshold.

[0115] For example, the turning angle threshold can be a value between 15° and 20°, or the turning angle threshold can be other values; the acceleration threshold can be a value between 0.5g and 0.7g, or the acceleration threshold can be other values, where 1g is 9.8 meters per square second.

[0116] In other implementations, the maximum avoidance capability of the vehicle is determined, including when the time limit (TTC) is less than or equal to a duration threshold. In practice, the duration threshold can be determined based on the vehicle's speed and the road surface adhesion coefficient of the road where the vehicle is located.

[0117] S1220, when the vehicle is determined to be in the obstacle avoidance phase according to the first planned path, the desired steering angle of the front wheels and the desired steering angle of the rear wheels are determined according to the curvature and position indicated by the first planned path, as well as the speed information; or, when the vehicle is determined to be in the straightening phase according to the first planned path, the desired steering angle of the front wheels and the desired steering angle of the rear wheels are determined according to the vehicle's front wheel steering angle and speed information.

[0118] In some implementations, the lateral position and heading angle of the vehicle are obtained; lateral error and heading angle error are determined based on the first planned path, the lateral position, and the heading angle, respectively. The lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path; the desired steering angles of the front and rear wheels are determined, including: determining front wheel feedforward and rear wheel feedforward based on the curvature and speed information of the first planned path, whereby the front wheel feedforward and rear wheel feedforward respectively indicate the feedforward of the front wheel steering angle and the feedforward of the rear wheel steering angle; determining front wheel feedback and rear wheel feedback based on the lateral error and heading angle error, whereby the front wheel feedback and rear wheel feedback respectively indicate the feedback of the front wheel steering angle and the feedback of the rear wheel steering angle; determining the desired steering angle of the front wheels based on the front wheel feedforward and the front wheel feedback; and determining the desired steering angle of the rear wheels based on the rear wheel feedforward and the rear wheel feedback.

[0119] For example, the aforementioned feedforward amount can be a tire steering angle feedforward amount, or a tire lateral force feedforward amount, or other parameters that can determine the tire steering angle feedforward amount; the feedback amount can be a tire steering angle feedback amount, or a tire lateral force feedback amount, or other parameters that can determine the tire steering angle feedback amount.

[0120] In some implementations, the method further includes: obtaining the vehicle's lateral position and heading angle; determining lateral error and heading angle error based on the first planned path, the lateral position, and the heading angle, respectively, where the lateral error is the difference between the vehicle's actual position and the position indicated by the first planned path, and the heading angle error is the difference between the vehicle's actual heading angle and the heading angle indicated by the first planned path; determining the desired steering angle of the front wheels and the desired steering angle of the rear wheels, respectively, including: determining a desired steering angle feedforward based on the curvature and speed information of the first planned path, where the desired steering angle feedforward includes both front wheel and rear wheel steering angle feedforwards; determining a desired steering angle feedback based on the lateral error and the heading angle error, where the desired steering angle feedback includes both front wheel and rear wheel steering angle feedbacks; and determining the desired steering angle of the front wheels and the desired steering angle of the rear wheels based on the desired steering angle feedforward and the desired steering angle feedback. For example, the method for determining the steering angle feedforward and steering angle feedback can be found in the description in S504, and will not be repeated here.

[0121] In some implementations, the method further includes: determining a tire lateral force feedforward based on the curvature and speed information of the first planned path; determining a tire lateral force feedback based on lateral error and heading angle error, where the lateral error is the difference between the vehicle's actual position and the position indicated by the first planned path, and the heading angle error is the difference between the vehicle's actual heading angle and the heading angle indicated by the first planned path; determining a desired tire lateral force based on the tire lateral force feedforward and tire lateral force feedback, where the desired tire lateral force includes the desired lateral force of the front wheels and the desired lateral force of the rear wheels; and determining the desired steering angle of the front wheels and the desired steering angle of the rear wheels based on the desired tire lateral force. For example, the method for determining the desired tire lateral force can be referred to the description in S504, and will not be repeated here.

[0122] In some implementations, when the vehicle is determined to be in the straightening phase according to the first planned path, the desired front wheel angle and the desired rear wheel angle are determined based on the vehicle's front wheel angle and speed information. This includes: determining the desired yaw rate based on the vehicle's front wheel angle and speed; determining the desired front wheel angle based on the vehicle's actual yaw rate and desired yaw rate; and determining the desired rear wheel angle based on the desired front wheel angle.

[0123] More specifically, determining the expected steering angle of the rear wheels based on the expected steering angle of the front wheels can be achieved by multiplying the expected steering angle of the front wheels by the gain coefficient. For example, the gain coefficient can be the gain coefficient K2 in method 500.

[0124] S1230 controls the vehicle to execute the desired steering angles of the front and rear wheels.

[0125] The steering assist control method provided in this application controls the front and rear wheels of the vehicle to steer simultaneously when the vehicle needs to avoid an obstacle. This allows obstacle avoidance to be completed even when the distance between the vehicle and the obstacle is relatively short, thus improving the vehicle's active safety capabilities. Furthermore, compared to controlling the vehicle to avoid obstacles using only the front wheels, controlling both the front and rear wheels simultaneously reduces the angle of steering wheel rotation required during obstacle avoidance. In human-driven or human-machine co-driving situations, this reduces the difficulty for the driver to take over the vehicle, thereby improving the driver's experience.

[0126] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between the various embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0127] The methods provided by the embodiments of this application have been described in detail above with reference to Figures 1 to 12. The apparatus provided by the embodiments of this application will now be described in detail with reference to Figures 13 and 14. It should be understood that the descriptions of the apparatus embodiments correspond to the descriptions of the method embodiments; therefore, any content not described in detail can be referred to the method embodiments above, and for the sake of brevity, will not be repeated here.

[0128] Figure 13 shows a schematic block diagram of a steering assist control device 2000 provided in an embodiment of this application. The device 2000 may include units for executing the methods described in the foregoing embodiments. Furthermore, each unit in the device 2000 implements a corresponding process of the above method embodiments. The device 2000 includes an acquisition unit 2010, which can be used to implement corresponding data acquisition or transmission / reception functions. The device 2000 also includes a processing unit 2020, which can be used to implement corresponding processing functions.

[0129] Optionally, the device 2000 further includes a storage unit, which can be used to store instructions and / or data. The processing unit 2020 can read the instructions and / or data in the storage unit so that the device can perform the relevant actions in the aforementioned method embodiments.

[0130] It should be understood that the specific process of each unit performing the above-mentioned corresponding steps has been described in detail in the above method embodiments, and will not be repeated here for the sake of brevity.

[0131] It should also be understood that the device 2000 described herein is embodied in the form of a functional unit. The terms “module” or “unit” may refer to application-specific ASICs, electronic circuits, processors (e.g., shared processors, proprietary processors, or group processors) and memory for executing one or more software or firmware programs, integrated logic circuits, and / or other suitable components that support the described functions.

[0132] The apparatuses described above have the function of implementing the corresponding steps in the methods described above. These functions can be implemented in hardware or by hardware executing corresponding software. The hardware or software includes one or more modules corresponding to the functions described above; for example, the acquisition unit 2010 can be replaced by a transceiver, and other units, such as the processing unit, can be replaced by a processor, used to execute the relevant processing operations in each method embodiment.

[0133] Exemplarily, the acquisition unit 2010 and processing unit 2020 can be disposed in the vehicle 100 shown in FIG. 1, or they can also be disposed in the system shown in FIG. 2. More specifically, the acquisition unit 2010 and processing unit 2020 can be disposed in the control module 240. Exemplarily, the operations performed by the acquisition unit 2010 and processing unit 2020 can be performed by a single processor, or they can be performed by different processors. In specific implementation, the one or more processors can be processors disposed in the vehicle 100 shown in FIG. 1; or, the device 2000 can be a chip disposed in the vehicle 100.

[0134] In the specific implementation process, the units in the above device can be fully or partially integrated together, or they can be implemented independently. In one implementation, these units are integrated together and implemented in the form of a system-on-a-chip (SoC).

[0135] Figure 14 is another schematic block diagram of the steering assist control device provided in an embodiment of this application. The device 2100 shown in Figure 14 may include a processor 2110, a transceiver 2120, and a memory 2130. The processor 2110, transceiver 2120, and memory 2130 are connected via internal interconnection paths. The memory 2130 is used to store instructions, and the processor 2110 is used to execute the instructions stored in the memory 2130 to implement the methods in the above embodiments. Optionally, the memory 2130 may be coupled to the processor 2110 via an interface or integrated with the processor 2110.

[0136] It should be noted that the transceiver 2120 mentioned above may include, but is not limited to, transceiver devices such as input / output interfaces, to realize communication between device 2100 and other devices or communication networks.

[0137] Memory 2130 can be volatile memory and / or non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM). For example, RAM can be used as an external cache. By way of example and not limitation, RAM includes various forms such as: static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous linked dynamic random access memory (SLDRAM), and direct rambus RAM (DR RAM).

[0138] Transceiver 2120 uses transceiver devices, such as but not limited to transceivers, to enable communication between device 2100 and other devices or communication networks to receive / send data / information for implementing the methods in the above embodiments.

[0139] This application also provides an intelligent driving device, which includes the device 2000 or device 2100 in the above embodiments.

[0140] This application also provides a computer program product, which includes computer program code. When the computer program code is run on a computer, it causes the computer to implement the methods described in the above embodiments of this application.

[0141] This application also provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to implement the methods described in the above embodiments of this application.

[0142] This application also provides a chip, including circuitry, for performing the methods described in the above embodiments of this application.

[0143] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0144] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. In this application, "at least one" means one or more, and "more" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0145] The use of prefixes such as "first" and "second" in this application embodiment is solely for distinguishing different descriptive objects and does not limit the position, order, priority, quantity, or content of the described objects. The use of ordinal numbers and other prefixes to distinguish descriptive objects in this application embodiment does not constitute a limitation on the described objects. The description of the described objects is found in the claims or the context of the embodiments, and the use of such prefixes should not constitute unnecessary restrictions.

[0146] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0147] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between the various embodiments are consistent and can be referenced by each other. Technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0148] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0149] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0150] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A steering assist control method characterized by, include: Obtain a first planned path and vehicle speed information, wherein the first planned path is used for the vehicle to avoid a first obstacle; When it is determined that the vehicle is in the obstacle avoidance phase according to the first planned path, the desired steering angle of the front wheels and the desired steering angle of the rear wheels are determined according to the curvature and position indicated by the first planned path and the speed information, respectively. or, When it is determined that the vehicle is in the straightening phase according to the first planned path, the desired front wheel angle and the desired rear wheel angle are determined according to the front wheel angle and the speed information of the vehicle. Control the vehicle to execute the desired steering angle of the front wheels and the desired steering angle of the rear wheels.

2. The method of claim 1, wherein, The method further includes: Obtain the lateral position and heading angle of the vehicle; The lateral error and heading angle error are determined based on the first planned path, the lateral position, and the heading angle, respectively. The lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path. Determining the desired steering angle of the front wheel and the desired steering angle of the rear wheel respectively includes: Based on the curvature of the first planned path and the speed information, the desired steering angle feedforward is determined, which includes the front wheel steering angle feedforward and the rear wheel steering angle feedforward. Based on the lateral error and the heading angle error, the desired steering angle feedback is determined, and the desired steering angle feedback includes the front wheel steering angle feedback and the rear wheel steering angle feedback. The desired steering angle of the front wheel and the desired steering angle of the rear wheel are determined based on the desired steering angle feedforward and desired steering angle feedback, respectively.

3. The method of claim 1, wherein, The method further includes: Based on the curvature of the first planned path and the speed information, the tire lateral force feedforward is determined; The tire lateral force feedback is determined based on the lateral error and the heading angle error. The lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path. The desired lateral force of the tire is determined based on the tire lateral force feedforward and the tire lateral force feedback, wherein the desired lateral force of the tire includes the desired lateral force of the front wheel and the desired lateral force of the rear wheel. Determining the desired steering angle of the front wheel and the desired steering angle of the rear wheel respectively includes: Based on the expected lateral force of the tires, the expected steering angles of the front wheels and the rear wheels are determined respectively.

4. The method according to any one of claims 1 to 3, characterized in that, When it is determined that the vehicle is in the straightening phase according to the first planned path, determining the desired front wheel steering angle and the desired rear wheel steering angle based on the vehicle's front wheel steering angle and speed information includes: The desired yaw rate is determined based on the front wheel steering angle and the vehicle's speed. The desired steering angle of the front wheels is determined based on the actual yaw rate of the vehicle and the desired yaw rate. The desired steering angle of the rear wheels is determined based on the desired steering angle of the front wheels.

5. The method according to any one of claims 1 to 4, characterized in that, The method further includes: Obtain obstacle information, motion state information, and steering capability information. The obstacle information indicates at least one obstacle that hinders the vehicle's movement, including the first obstacle. The motion state information indicates the vehicle's position, speed, and heading angle. The steering capability information indicates the maximum steering angle of the vehicle's front wheels and the maximum steering angle of the vehicle's rear wheels. Based on the motion state information and the steering capability information, the maximum obstacle avoidance capability of the vehicle is determined; The process of obtaining the first planned path includes: When the vehicle is able to avoid the first obstacle under the maximum avoidance capability, the first planned path is obtained.

6. The method of claim 5, wherein, The maximum obstacle avoidance capability indicator is the maximum lateral displacement that the vehicle can achieve within a first distance by controlling the steering angles of the front and rear wheels of the vehicle, where the first distance is the distance between the vehicle and the first obstacle at the current moment.

7. The method according to claim 5 or 6, characterized in that, The method further includes: Based on the motion state information and the maximum front wheel steering angle, the front wheel avoidance capability of the vehicle is determined. The front wheel avoidance capability indicates the maximum lateral displacement that the vehicle can achieve within a second distance by controlling the front wheel steering angle. The second distance is the distance between the vehicle and the first obstacle at the current moment. Determining the vehicle's maximum avoidance capability includes: The maximum avoidance capability of the vehicle is determined when the vehicle is unable to avoid the first obstacle under the front wheel avoidance capability, or when the front wheel turning angle required to avoid the first obstacle is greater than a turning angle threshold and / or the lateral acceleration required to avoid the first obstacle is greater than or equal to an acceleration threshold.

8. The method according to claim 5 or 6, characterized in that, Determining the vehicle's maximum avoidance capability includes: The maximum avoidance capability of the vehicle is determined when the collision time TTC is less than or equal to the duration threshold.

9. A steering assist control device characterized by comprising: include: The acquisition unit is used to acquire a first planned path and vehicle speed information, wherein the first planned path is used for the vehicle to avoid a first obstacle; The processing unit is configured to determine the desired front wheel steering angle and the desired rear wheel steering angle based on the curvature and position indicated by the first planned path and the speed information when it is determined that the vehicle is in the obstacle avoidance phase according to the first planned path. or, When it is determined that the vehicle is in the straightening phase according to the first planned path, the desired front wheel angle and the desired rear wheel angle are determined according to the front wheel angle and the speed information of the vehicle. The processing unit is also configured to: control the vehicle to execute the desired front wheel steering angle and the desired rear wheel steering angle.

10. The apparatus of claim 9, wherein, The acquisition unit is also used for: Obtain the lateral position and heading angle of the vehicle; The processing unit is configured to: determine the lateral error and the heading angle error based on the first planned path, the lateral position, and the heading angle, respectively. The lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path. Based on the curvature of the first planned path and the speed information, the desired steering angle feedforward is determined, which includes the front wheel steering angle feedforward and the rear wheel steering angle feedforward. Based on the lateral error and the heading angle error, the desired steering angle feedback is determined, and the desired steering angle feedback includes the front wheel steering angle feedback and the rear wheel steering angle feedback. The desired steering angle of the front wheel and the desired steering angle of the rear wheel are determined based on the desired steering angle feedforward and desired steering angle feedback, respectively.

11. The apparatus of claim 9, wherein, The processing unit is used for: Based on the curvature of the first planned path and the speed information, the tire lateral force feedforward is determined; The tire lateral force feedback is determined based on the lateral error and the heading angle error. The lateral error is the difference between the actual position of the vehicle and the position indicated by the first planned path, and the heading angle error is the difference between the actual heading angle of the vehicle and the heading angle indicated by the first planned path. The desired lateral force of the tire is determined based on the tire lateral force feedforward and the tire lateral force feedback, wherein the desired lateral force of the tire includes the desired lateral force of the front wheel and the desired lateral force of the rear wheel. Based on the expected lateral force of the tires, the expected steering angles of the front wheels and the rear wheels are determined respectively.

12. The apparatus according to any one of claims 9 to 11, characterized in that, The processing unit is used for: The desired yaw rate is determined based on the front wheel steering angle and the vehicle's speed. The desired steering angle of the front wheels is determined based on the actual yaw rate of the vehicle and the desired yaw rate. The desired steering angle of the rear wheels is determined based on the desired steering angle of the front wheels.

13. The apparatus of any one of claims 9-12, wherein, The acquisition unit is also used for: Obtain obstacle information, motion state information, and steering capability information. The obstacle information indicates at least one obstacle that hinders the vehicle's movement, including the first obstacle. The motion state information indicates the vehicle's position, speed, and heading angle. The steering capability information indicates the maximum steering angle of the vehicle's front wheels and the maximum steering angle of the vehicle's rear wheels. The processing unit is used to: determine the maximum obstacle avoidance capability of the vehicle based on the motion state information and the steering capability information; The acquisition unit is used for: When the vehicle is able to avoid the first obstacle under the maximum avoidance capability, the first planned path is obtained.

14. The apparatus of claim 13, wherein, The maximum obstacle avoidance capability indicator is the maximum lateral displacement that the vehicle can achieve within a first distance by controlling the steering angles of the front and rear wheels of the vehicle, where the first distance is the distance between the vehicle and the first obstacle at the current moment.

15. The apparatus of claim 13 or 14, wherein, The processing unit is also used for: Based on the motion state information and the maximum front wheel steering angle, the front wheel avoidance capability of the vehicle is determined. The front wheel avoidance capability indicates the maximum lateral displacement that the vehicle can achieve within a second distance by controlling the front wheel steering angle. The second distance is the distance between the vehicle and the first obstacle at the current moment. The maximum obstacle avoidance capability of the vehicle is determined when the vehicle is unable to avoid the first obstacle under the front wheel avoidance capability, or when the front wheel turning angle required to avoid the first obstacle is greater than a turning angle threshold and / or the lateral acceleration required to avoid the first obstacle is greater than or equal to an acceleration threshold.

16. The apparatus of claim 13 or 14, wherein, The processing unit is used for: The maximum avoidance capability of the vehicle is determined when the collision time TTC is less than or equal to the duration threshold.

17. A steering assist control device characterized by comprising: include: A processor for executing a computer program stored in memory to cause the apparatus to perform the method as described in any one of claims 1 to 8.

18. A computer-readable storage medium, characterized in that, It stores instructions that, when executed by a processor, implement the method as described in any one of claims 1 to 8.

19. A chip, characterized by The chip includes circuitry for performing the method as described in any one of claims 1 to 8.

20. A computer program product, characterised in that, The computer program product includes: computer program code, which, when executed by a processor, implements the method as described in any one of claims 1 to 8.

21. A vehicle characterized by Includes the apparatus as claimed in any one of claims 9 to 17, or the computer-readable storage medium as claimed in claim 18, or the chip as claimed in claim 19, or the vehicle is equipped with the computer program product as claimed in claim 20.

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