In-vehicle device, in-vehicle system, and hands-free driving assistance method

Abstract

The present invention provides an in-vehicle device, an in-vehicle system and a method for hands-free driving assistance, the in-vehicle device including: an acquisition module configured to acquire a hands-free assistance status signal from the hands-free driving assistance system of the vehicle and acquire a steering assistance status signal from the steering system of the vehicle, a confirmation module configured to confirm whether the hands-free driving assistance function of the vehicle is activated based on the hands-free assistance status signal and to confirm whether a fault occurs in the steering system based on the steering assistance status signal, a trigger module configured to trigger a brake jerk in a brake system of the vehicle when it is confirmed that the hands-free driving assistance function is activated and a fault occurs in the steering system, and a determination module configured to calculate a braking force for the brake jerk for use in increasing dynamic pressure in the brake system during the brake jerk in real time and based on the mass of the vehicle, the duration of the brake jerk, and the rate of change of the longitudinal deceleration of the vehicle.

Description

[Technical Field]

[0001] The present application generally relates to vehicle functional safety in hands-free driving assistance, and more particularly to an in-vehicle device for hands-free driving assistance and an in-vehicle system for hands-free driving assistance, and further to a corresponding method for hands-free driving assistance and a corresponding machine-readable storage medium. [Background technology]

[0002] In the research and development of hands-free driving assistance, vehicle safety is of the utmost importance. For example, when a host vehicle is undergoing a hands-free driving assistance process, if it is predicted that the host vehicle may deviate from its driving lane (current lane), the steering system must respond immediately to steer the host vehicle back to the current lane. However, if a fault occurs in the vehicle's steering system at this time and the steering system loses its steering assist capability, the host vehicle may immediately deviate from the current lane, potentially causing a serious collision.

[0003] In view of this, an existing solution is to use a redundant steering system in a vehicle, so that if a failure occurs in the primary steering system during a hands-free driving assistance process of the vehicle, the backup steering system can be immediately activated to perform the steering assistance function. However, the redundant steering system significantly increases the vehicle cost, and therefore has not been widely accepted.

[0004] Another existing solution is to sound an acoustic / optical alarm in the vehicle. Research has shown that drivers usually take over the vehicle in a timely manner after receiving the acoustic / optical alarm. However, some drivers take over the vehicle while holding the steering wheel with only one hand. This makes it difficult for the driver to operate the steering wheel to steer the vehicle because manually turning the steering wheel is excessively heavy when the steering assistance function of the vehicle's steering system is lost, and therefore, it is generally impossible to perform quick maneuvering of the vehicle with one hand on the steering wheel. In this case, the driver responds by taking over the vehicle, but the vehicle still deviates from its current lane.

[0005] Therefore, there is a need to consider effective security measures to solve the above problems in the prior art. Summary of the Invention [Problem to be solved by the invention]

[0006] In this context, the present invention aims to provide a solution for hands-free driving assistance in line with functional safety standards for road vehicles. [Means for solving the problem]

[0007] According to a first aspect of the present invention, there is provided an in-vehicle device for hands-free driving assistance, the in-vehicle device including: an acquisition module configured to acquire a hands-free assistance status signal from a hands-free driving assistance system of the vehicle and to acquire a steering assistance status signal from a steering system of the vehicle; a confirmation module configured to confirm whether the hands-free driving assistance function of the vehicle is activated based on the hands-free assistance status signal and to confirm whether a fault has occurred in the steering system based on the steering assistance status signal; a trigger module configured to trigger a brake jerk in a braking system of the vehicle when it is confirmed that the hands-free driving assistance function is activated and that a fault has occurred in the steering system; and a determination module configured to calculate, in real time, a braking force against the brake jerk to be used for increasing dynamic pressure in the braking system during the brake jerk based on the mass of the vehicle, the duration of the brake jerk, and the rate of change of longitudinal deceleration of the vehicle.

[0008] According to a second aspect of the present invention, there is provided an in-vehicle system for hands-free driving assistance, the in-vehicle system including the above-mentioned in-vehicle device configured to check whether a brake jerk should be triggered and determine a dynamic braking force in response to the brake jerk when it is determined whether the brake jerk should be triggered, and a human-machine interaction interface constructed to provide information in the vehicle to remind a user to hold the steering wheel with both hands and take over control of the vehicle.

[0009] According to a third aspect of the present invention, there is provided a method for hands-free driving assistance, optionally executed by the above-described in-vehicle device and / or the above-described in-vehicle system, including: acquiring a hands-free assistance status signal from the vehicle's hands-free driving assistance system and acquiring a steering assistance status signal from the vehicle's steering system, determining whether the vehicle's hands-free driving assistance function is activated based on the hands-free assistance status signal and determining whether a fault has occurred in the steering system based on the steering assistance status signal, triggering a brake jerk of the vehicle in a brake system of the vehicle when it has been determined that the hands-free driving assistance function is activated and the steering system has a fault, and calculating, in real time, a braking force for the brake jerk to be used for increasing dynamic pressure in the brake system during the brake jerk based on the vehicle mass, the duration of the brake jerk, and a rate of change of longitudinal deceleration of the vehicle.

[0010] According to a fourth aspect of the present invention, there is provided a machine-readable storage medium storing executable instructions that, when executed, cause one or more processors to perform the above-described method.

[0011] A summary of major aspects of the present invention has been provided above in order to facilitate a basic understanding of these aspects. The summary is not intended to describe key or critical 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 summary is intended to provide some implementations of these aspects in a simplified manner as a prelude to the detailed description provided below. [Brief explanation of the drawings]

[0012] [Figure 1] 1 illustrates a schematic of an environment in which some implementations of the present invention may be practiced. [Figure 2] 1 is a schematic block diagram of an in-vehicle device according to an implementation of the present invention; [Figure 3] 1 is a flowchart of a hands-free driving assistance process according to one implementation of the present invention. [Figure 4] 1 illustrates a curve of brake jerk according to one implementation of the present invention. [Figure 5] 1 is a flowchart of a method for hands-free driving assistance according to one implementation of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Vehicle hands-free driving assistance functions should meet the functional safety requirements for road vehicles. For example, hands-free driving assistance functions must comply with the ISO 26262 standard for functional safety of automotive electronic systems.

[0014] For this reason, careful research has been conducted into the driver's controllability during hands-free driving assistance. Research results have shown that the use of brake jerk warning measures allows the driver to adequately recognize the urgency of the current situation, and instinctively grasp the steering wheel with both hands and take over the vehicle.

[0015] Additionally, brake jerk warning measures may cause some discomfort. However, the likelihood of a loss of lateral control during the vehicle's life cycle is very low. For example, a loss of lateral control may occur at most once during the vehicle's life cycle. Therefore, brake jerk, being the most effective warning measure, is acceptable.

[0016] Furthermore, after research and demonstration, it has been determined that the probability of both loss of lateral control and inability to perform braking jerk occurring in the same driving cycle during the vehicle's life cycle is extremely low (acceptable from a safety perspective). For example, the probability of both loss of lateral control and inability to perform braking jerk occurring during the vehicle's life cycle is approximately 10^(-6)(10 -6 ) Therefore, the brake jerk means of the present invention is robust and feasible.

[0017] The present invention mainly relates to a safety solution for hands-free driving assistance, which can detect loss of lateral control of a vehicle during hands-free driving assistance, trigger a brake jerk in time, and determine appropriate parameters of the brake jerk.

[0018] The technical solutions of the embodiments of the present invention are particularly applicable to safety solutions for hands-free driving assistance in scenarios consisting of highways, flyovers, national highways, etc.

[0019] According to the technical solutions of the embodiments of the present invention, it is possible to achieve the road vehicle safety goal for hands-free driving assistance functions, namely, to prevent the vehicle from deviating from the host lane through the hands-free driving assistance process, and meet the Automotive Safety Level (ASIL) of the vehicle.

[0020] Specific embodiments of the present invention are described below in conjunction with the accompanying drawings.

[0021] 1 is a schematic diagram illustrating an environment in which some implementations of the present invention may be implemented, which may be an in-vehicle application environment. The environment illustrated in FIG. 1 mainly includes a hands-free driving assistance system 1, a brake system 2, a steering system 3, a human-machine interaction interface 4, and an in-vehicle device 5, which are arranged in a vehicle.

[0022] The hands-free driving assistance system 1 accepts user inputs for activating a hands-free driving assistance function and provides control logic for the hands-free driving assistance. The control logic of the system can be set in a domain controller (not shown) of the vehicle.

[0023] When the brake system 2 receives a command to trigger a brake jerk, it performs the brake jerk based on the brake jerk parameters (e.g., the duration of the brake jerk and the dynamic braking force during the duration) determined in accordance with an embodiment of the present invention.

[0024] The steering system 3 provides lateral control of the vehicle. When there is no obstacle, the steering system 3 communicates with the brake system 2 and the hands-free driving assistance system 1 (domain controller) in real time, and can understand each other's status.

[0025] The human-machine interaction interface 4 provides interaction between a user and a vehicle head unit in a vehicle. The human-machine interaction interface 4 can receive user input and output information to the user. The human-machine interaction interface 4 can implement information exchange between a user in a vehicle and the vehicle head unit through various human-machine interaction methods. The human-machine interaction methods may include one or more of screen touch, automatic speech recognition (ASR), behavior recognition (e.g., gesture recognition), eye recognition, and brainwave recognition.

[0026] One aspect of the present invention provides an in-vehicle system for hands-free driving assistance, which may include a human-machine interaction interface (HMI) 4 and an in-vehicle device 5. The in-vehicle device 5 is configured to determine whether to trigger a brake jerk, and determine a braking force for the brake jerk when it is determined to trigger the brake jerk. The human-machine interaction interface 4 is configured to provide information to remind a user in the vehicle to hold the steering wheel with both hands and take over control of the vehicle.

[0027] The in-vehicle device 5 includes a hands-free driving assistance strategy according to an embodiment of the present invention. Fig. 2 shows the in-vehicle device 5 according to an implementation of the present invention, which mainly includes a detection module 51, an acquisition module 52, a confirmation module 53, a trigger module 54, and a determination module 55. The detection module 51, the acquisition module 52, the confirmation module 53, the trigger module 54, and the determination module 55 may be disposed in the brake system 2 of the vehicle. The operation principles and processes of the modules are described in detail below.

[0028] In one embodiment, the in-vehicle device 5 may further include a reminder module 56. The reminder module 56 may be located in a domain controller of the vehicle. The reminder module 56 communicates with the human-machine interaction interface 4 and can output a reminder signal to the human-machine interaction interface 4 while a brake jerk is triggered in the vehicle, so that the human-machine interaction interface 4 provides information to remind the user to hold the steering wheel with both hands and take over the vehicle.

[0029] It will be understood that the modules within the on-board device 5 may be implemented by software or hardware, or a combination of software and hardware, and that the modules are named logically (functionally) rather than defined with respect to their physical location or particular implementation. For example, the modules may be located on the same chip or circuit, or may be located on different chips or circuits.

[0030] 3 illustrates a hands-free driving assistance process 300 according to an implementation of the present invention. The operating principles and processes of the in-vehicle system and in-vehicle device according to an embodiment of the present invention will be described below with reference to FIG.

[0031] In block 302, the detection module 51 detects whether the vehicle's brake system 2 is capable of generating brake jerk. If the detection result indicates that the brake system 2 is unable to generate brake jerk, a control signal is sent to the hands-free driving assistance system 1 to disable the hands-free driving assistance function. In this case, the hands-free driving assistance function cannot be activated, and the driver must drive the vehicle with both hands on the steering wheel, and the hands-free driving assistance process 300 is terminated (block 304). If the detection result indicates that the brake system 2 is capable of generating brake jerk, activation of the hands-free driving assistance function is permitted, and the hands-free driving assistance process 300 continues.

[0032] In one embodiment, at the start of each driving cycle of the vehicle, the detection module 51 performs a self-check on the brake system 2. For example, the detection module 51 sends a trial operation control signal to the motor of the brake system 2 to check whether the motor can operate properly. If the motor of the brake system can operate properly, the brake system is considered to be able to generate brake jerk. Conversely, if the motor of the brake system cannot operate, the brake system is considered to be unable to generate brake jerk.

[0033] In block 306, the acquisition module 52 acquires a hands-free assistance status signal from the hands-free driving assistance system 1 and a steering assistance status signal from the steering system 3. The hands-free assistance status signal may indicate whether a hands-free driving assistance function is activated. The steering assistance status signal may indicate the state of the steering system.

[0034] In block 308, the verification module 53 verifies whether the conditions that cause brake jerk are met, i.e., whether the hands-free driving assistance function is activated and whether the steering system is faulty.

[0035] In block 3081, the confirmation module 53 confirms whether the hands-free driving assistance function is activated based on the hands-free assistance status signal. The hands-free assistance status signal may include a flag indicating whether the hands-free driving assistance function is activated. The confirmation module 53 identifies the information of the flag to determine whether the hands-free driving assistance function is activated.

[0036] In block 3082, the confirmation module 53 confirms whether a fault has occurred in the steering system based on the steering assistance status signal. The steering system 3 transmits the steering assistance status signal to the brake system 2 at predetermined time intervals. The steering assistance status signal may include multiple fields, each representing one functional state of the steering system. For example, the multiple fields correspond to the microcontroller state, power state, and communication state of the steering system, respectively. If a fault has occurred in any functional state of the steering system, it is considered that a fault has occurred in the steering system.

[0037] In addition, the brake system may not be able to receive the steering assistance status signal due to a failure in communication between the steering system and the brake system. In this case, detection can be performed through a timeout check. For example, if the brake system does not receive the steering assistance status signal for a predetermined duration, it is confirmed that the steering system has a failure. The steering assistance status signal should be transmitted between the steering system and the brake system at predetermined intervals (i.e., a predetermined duration), and the predetermined duration is preset in both the brake system and the steering system as a detection criterion. In other words, the brake system has a check criterion for checking whether the steering assistance status signal has timed out.

[0038] From this, it can be seen that if there is a failure in at least one of the steering assist function of the steering system and the communication between the steering system and the brake system, it is confirmed that there is a failure in the steering system.

[0039] It will be appreciated that the present invention is intended to maximize fault detection and safety measures, not to differentiate between types or causes of faults. In other words, the steering system verification logic is designed to detect faults, but not to identify their causes or types.

[0040] In block 310, if the confirmation module 53 confirms that the hands-free driving assistance function is activated and that a fault has occurred in the steering system, the trigger module 54 triggers a brake jerk.

[0041] If the verification module 53 determines that the hands-free driving assistance function is not activated and that the steering system is not faulty, the process returns to block 306 .

[0042] In block 312, the determination module 55 determines a braking force for the brake jerk, so that the brake system performs the brake jerk using the determined braking force. The braking force for the brake jerk changes dynamically throughout the brake jerk process and is related to the mass of the vehicle, the duration of the brake jerk, and the rate of change of the longitudinal deceleration of the vehicle, which can represent the degree of vehicle sway (vibration) during the braking process.

[0043] Three parameters, namely, the mass of the vehicle, the duration of the brake jerk, and the rate of change of the vehicle's longitudinal deceleration, together affect the user's perception of the brake jerk, i.e., whether it is sufficient to warn the user that a brake jerk has been triggered. Generally, the user's perception should not be too weak so that the brake jerk does not provide sufficient warning to the user.

[0044] In one embodiment, the rate of change of the vehicle's longitudinal deceleration and the total duration of the brake jerk are both variables in the entire brake jerk process. In this embodiment, lower limits can be set separately for the rate of change of the vehicle's longitudinal deceleration and the total duration of the brake jerk to ensure that the two parameter values ​​are not too small to achieve the above-mentioned warning effect. Of course, upper limits can also be set separately for the two parameters to prevent the two parameter values ​​from becoming too large and thus causing damage to the vehicle or the driver. In this embodiment, within the respective upper and lower limits of the two parameters, the rate of change of the vehicle's longitudinal deceleration and / or the total duration of the brake jerk can be adjusted based on a specific application scenario to a level sufficient to attract the user's attention and prompt them to take over the vehicle with both hands on the steering wheel.

[0045] In another embodiment, the brake jerk has a predetermined duration. The predetermined duration can be obtained through experimentation and / or model calculation. The determination module 55 calculates the braking force for the brake jerk based on the following formula: F(t)=J(k) * m * t where F(t) is the braking force required for the brake jerk at the instant t, t is the duration of the brake jerk, and the maximum value of t is the predetermined duration of the brake jerk. J(k) is the rate of change of the vehicle's longitudinal deceleration related to the vehicle's suspension stiffness k; m is the mass of the vehicle.

[0046] In this embodiment, the total duration of the brake jerk is preset, and the dynamic braking force within the total duration is calculated in real time. The rate of change of the vehicle's longitudinal deceleration J(k) can be determined by table lookup. For example, a correlation table containing the correlation between the J(k) value and the vehicle's suspension stiffness k is stored in the determination module 55. The determination module 55 inputs the vehicle's current suspension stiffness into the correlation table, and then finds the corresponding J(k) value.

[0047] From this, it can be seen that a larger vehicle mass and / or a smaller vehicle suspension stiffness indicates a larger braking force in response to brake jerk. Conversely, a smaller vehicle mass and / or a larger vehicle suspension stiffness indicates a smaller braking force in response to brake jerk. In this way, a matching braking force in response to brake jerk is provided for different vehicle parameters, thereby more effectively realizing vehicle safety.

[0048] FIG. 4 shows a curve of brake jerk according to an embodiment of the present invention. Referring to FIG. 4, the horizontal axis represents time t, the vertical axis represents longitudinal deceleration a of the vehicle, and the curve represents the rate of change of longitudinal deceleration a of the vehicle with respect to time t. The position marked "TRIGGER" represents the trigger point of the brake jerk (i.e., the moment when the brake jerk trigger signal is generated). t1 represents the preparation period of the brake system after receiving the trigger signal. For example, the brake system calculates the brake fluid volume and performs pre-filling within the preparation period. t2 represents the total duration of the brake jerk. J(k) represents the rate of change of longitudinal deceleration of the vehicle during braking jerk.

[0049] In one embodiment, the preparation period t1 is 300 ms. The total duration of the brake jerk t2 is 350 ms. The rate of change of the longitudinal deceleration of the vehicle J(k) is 17 m / s 3 is.

[0050] In addition, while a brake jerk is triggered in the vehicle, information can be presented on the human-machine interaction interface to remind the driver to hold the steering wheel with both hands and take over the vehicle. For example, the steering system 3 sends a fault signal to the domain controller when a fault occurs in the steering system, the reminder module 56 arranged in the domain controller generates a reminder signal in response to the fault signal, and then sends the reminder signal to the human-machine interaction interface 4, so that the human-machine interaction interface 4 provides information in the vehicle to remind the driver to hold the steering wheel with both hands and take over the vehicle.

[0051] It will be appreciated that if a communication failure occurs in the steering system and therefore a fault signal cannot be sent, the domain controller can determine through a timeout confirmation logic similar to that described above that a fault has occurred in the steering system, generate a reminder signal, and send the reminder signal to the human-machine interaction interface.

[0052] 5 illustrates a method 500 for hands-free driving assistance according to one implementation of the present invention. The method may be performed by an in-vehicle device or an in-vehicle system as described above, and the previous descriptions of in-vehicle devices and systems are also applicable.

[0053] Referring to FIG. 5, in step 502, a hands-free assistance status signal from a hands-free driving assistance system of the vehicle and a steering assistance status signal from a steering system of the vehicle are obtained.

[0054] In step 504, it is determined whether the vehicle's hands-free driving assistance function is activated based on the hands-free assistance status signal, and whether a fault has occurred in the steering system based on the steering assistance status signal.

[0055] In step 506, if it is determined that the hands-free driving assistance function is activated and that a fault has occurred in the steering system, a vehicle brake jerk is triggered in the vehicle's braking system.

[0056] In step 508, a braking force for the brake jerk is calculated in real time based on the vehicle mass, the duration of the brake jerk, and the rate of change of the vehicle's longitudinal deceleration for use in increasing the dynamic pressure in the brake system during the brake jerk.

[0057] The present invention further provides a machine-readable storage medium storing executable instructions that, when executed, cause one or more processors to perform the above-described method 500 for hands-free driving assistance.

[0058] It will be understood that all of the above-mentioned modules can be implemented in a variety of ways. These modules may be implemented as hardware, software, or a combination thereof. Additionally, any of these modules may be further divided into sub-modules in terms of functionality or combined together.

[0059] It will be understood that processors may be implemented using electronic hardware, computer software, or any combination thereof. Whether these processors are implemented as hardware or software may depend on the particular application and the overall design constraints imposed on the system. As an example, a processor, any portion of a processor, or any combination of processors provided in the present invention may be implemented as a microprocessor, a microcontroller, a digital signal processor (DSP), a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, gate logic, discrete hardware circuits, and other suitable processing components configured to perform the various functions described in this disclosure. The functionality of a processor, any portion of a processor, or any combination of processors provided in the present invention may be implemented as software executed by a microprocessor, a microcontroller, a DSP, or other suitable platform.

[0060] It can be understood that software should be broadly considered to represent instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, threads of execution, processes, functions, etc. Software can reside on a computer-readable medium. The computer-readable medium may include, for example, memory, which may be, for example, a magnetic storage device (such as a hard disk, floppy disk, or magnetic stripe), a compact disk, a smart card, a flash memory device, random access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, or a removable disk. While memory is shown as being separate from the processor in various aspects presented herein, memory (such as cache or registers) may also be located within the processor.

[0061] Although several implementations have been described above, these implementations are presented as examples only and are not intended to limit the scope of the present invention. The appended claims and their equivalents are intended to cover all modifications, substitutions and alterations made within the scope and subject matter of the present invention.

Claims

1. An in-vehicle device for hands-free driving assistance, an acquisition module configured to acquire a hands-free assistance status signal from a hands-free driving assistance system of a vehicle and to acquire a steering assistance status signal from a steering system of the vehicle; a confirmation module configured to confirm whether a hands-free driving assistance function of the vehicle is activated based on the hands-free assistance status signal, and to confirm whether a fault has occurred in the steering system based on the steering assistance status signal; a trigger module configured to trigger a brake jerk in a braking system of the vehicle when it is determined that the hands-free driving assistance function is activated and that a fault has occurred in the steering system; and a determination module configured to calculate in real time a braking force for the brake jerk for use in increasing dynamic pressure in the braking system during the brake jerk based on the mass of the vehicle, a preset total duration of the brake jerk, and a rate of change of longitudinal deceleration of the vehicle determined by table lookup; and An in-vehicle device comprising:

2. The in-vehicle device further comprises a detection module configured to detect whether the braking system of the vehicle is capable of generating the brake jerk before the hands-free driving assistance function is activated; If the detection result indicates that the brake system is unable to generate the brake jerk, sending a control signal to the hands-free driving assistance system of the vehicle to disable the hands-free driving assistance function and terminate the hands-free driving assistance process; if the detection result indicates that the brake system is able to generate the brake jerk, activating the hands-free driving assistance function and continuing the hands-free driving assistance process. The in-vehicle device according to claim 1 .

3. the rate of change of longitudinal deceleration of the vehicle and the total duration of the braking jerk are both variables, each having a predetermined lower and upper limit; the determination module is configured to adjust both the rate of change of the longitudinal deceleration of the vehicle and the total duration of the braking jerk to a level sufficient to attract a user's attention to take over the vehicle by keeping both hands on the steering wheel. The in-vehicle device according to claim 1 .

4. The brake jerk has the total duration set in advance, and the determination module is configured to calculate the braking force for the brake jerk based on the following formula: F(t)=J(k) ＊ m ＊ t where F(t) is the braking force required for said brake jerk at instant t, t is the total duration of the brake jerk that is preset, and the maximum value of t is the predetermined duration of the brake jerk; J(k) is the rate of change of the longitudinal deceleration of the vehicle as determined by the table lookup, related to suspension stiffness k of the vehicle; m is the mass of the vehicle; The in-vehicle device according to claim 1 .

5. The determination module has a correlation table containing correlations between the J(k) values ​​and suspension stiffness of the vehicle, and the determination module searches the correlation table for a J(k) value corresponding to the current suspension stiffness of the vehicle from the correlation table. The in-vehicle device according to claim 4.

6. When determining based on the steering assist status signal that at least one of a steering assist function of the steering system and communication between the steering system and the brake system has been lost, the confirmation module determines that a fault has occurred in the steering system. The in-vehicle device according to claim 1 .

7. The on-board device further comprises a reminder module configured to send a reminder signal to a human-machine interaction interface of the vehicle while the brake jerk is triggered to provide information to remind a user in the vehicle to take over the vehicle with both hands on a steering wheel. The in-vehicle device according to claim 2 .

8. the detection module, the acquisition module, the confirmation module, the trigger module, and the determination module are disposed in the brake system of the vehicle, and the reminder module is disposed in a domain controller of the vehicle; The in-vehicle device according to claim 7.

9. An in-vehicle system for hands-free driving assistance, 2. The vehicle-mounted device according to claim 1, wherein the vehicle-mounted device is configured to check whether or not a brake jerk is to be triggered, and when it is confirmed that the brake jerk is to be triggered, determine a braking force for the brake jerk; a human-machine interaction interface configured to provide information within a vehicle to remind a user to take over control of the vehicle with both hands on a steering wheel; An in-vehicle system comprising:

10. A method for hands-free driving assistance optionally performed by the in-vehicle device according to claim 1 or the in-vehicle system according to claim 9, comprising: obtaining a hands-free assistance status signal from a hands-free driving assistance system of a vehicle and a steering assistance status signal from a steering system of the vehicle; determining whether a hands-free driving assistance function of the vehicle is operating based on the hands-free assistance status signal, and determining whether a fault has occurred in the steering system based on the steering assistance status signal; When the hands-free driving assistance function is activated and a fault in the steering system is detected, triggering a brake jerk of the vehicle in a braking system of the vehicle; calculating in real time a braking force for the brake jerk for use in increasing dynamic pressure in the brake system during the brake jerk based on the mass of the vehicle, a predetermined total duration of the brake jerk, and a rate of change of longitudinal deceleration of the vehicle determined by table lookup; A method comprising:

11. 11. A machine-readable storage medium storing executable instructions that, when executed, cause one or more processors to perform the method of claim 10.

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