Driving system, corresponding program and corresponding software for ensuring automatic lateral guidance in hands-off driving operation

Abstract

The driving system for a motor vehicle with a steering wheel according to the invention comprises a hands-off driving function for automated driving, wherein the hands-off driving function in an activated state allows a hands-off driving operation with at least automated lateral guidance without the driver having to touch the steering wheel, during which automated lateral guidance a controllable steering system can be controlled in accordance with a target signal on which the control is based, and the driving system is designed to generate the target signal. There are a hand detection device for detecting when the driver is touching the steering wheel and one or more hands-off safety mechanisms to ensure the automated lateral guidance in the hands-off driving operation. The driving system is designed to deactivate the hands-off driving function without deactivating at least one of the hands-off safety mechanisms, to check, by means of the hand detection device, that the driver is touching the steering wheel, and to also deactivate the one or more hands-off safety mechanisms in response to the check that the driver is touching the steering wheel.

Description

Technical Field

[0001] The present invention relates to a driving system for a motor vehicle with a steering wheel, having a hands-free driving function for automatic driving, wherein the hands-free driving function, when activated, allows hands-free driving operation with at least automatic lateral guidance without the driver touching the steering wheel. Background Technology

[0002] In the context of this article, the term "autonomous driving" is understood as driving with automatic longitudinal and / or lateral guidance. Automated driving can be, for example, driving for extended periods on a highway or driving for limited periods within a parking area. The term "autonomous driving" includes any level of automation. Exemplary levels of automation are assisted, partially automated, highly automated, fully automated, and autonomous driving (the degree of automation increases accordingly). The five levels of automation mentioned above correspond to SAE Levels 1 to 5 of the SAE J3016 standard (SAE - Society of Automotive Engineers). For assisted driving (SAE Level 1), the system performs longitudinal or lateral guidance in certain driving situations. For partially automated driving (SAE Level 2), the system takes over longitudinal and lateral guidance in certain driving situations, where the driver must therefore continuously monitor the system, as in assisted driving. For highly automated driving (SAE Level 3), the system takes over longitudinal and lateral guidance in certain driving situations without requiring continuous driver monitoring; however, the driver must be able to take over vehicle guidance at the system's request for a certain period. For fully automated driving (SAE Level 4), the system takes over vehicle guidance in certain driving situations, even if the driver does not respond to intervention requests, thus the driver is no longer a backup option. For autonomous driving (SAE Level 5), the system can perform all aspects of dynamic driving tasks under any road and environmental conditions, which are also controlled by a human driver.

[0003] For driving functions with at least automatic lateral guidance conforming to SAE Level 1 and 2, a distinction can be made between hands-free driving and hands-free driving. In hands-free driving, the driver must keep both hands (or one hand, depending on the system design) on the steering wheel at all times (brief interruptions are usually allowed). In hands-free driving, hands-free driving is permitted through automatic longitudinal and lateral guidance without the driver touching the steering wheel. Hands-free driving functions conforming to SAE Level 2 are also called Level 2+ driving functions. Compared to their corresponding hands-free driving functions, hands-free driving functions, especially Level 2+ functions, significantly improve driver comfort because the driver does not need to keep both hands on the steering wheel.

[0004] Driving capabilities according to SAE Level 3, 4, or 5 are typically implemented as hands-free driving capabilities; vehicles configured for permanently automated operation under SAE Level 4 and 5 (especially so-called robotaxis vehicles) may even operate without a steering wheel.

[0005] Driving systems for autonomous driving typically include multiple driving functions for autonomous driving, which have different levels of automation, such as Level 1, Level 2, Level 2+ or Level 1, Level 2, Level 2+, Level 3.

[0006] For autonomous driving systems with at least automatic lateral guidance, where, for example, it is necessary to check for touches on the steering wheel during active hand-held driving, a so-called hand-held recognition device is typically included to identify driver touches on the steering wheel. For this purpose, a sensing mechanism, such as a capacitive or resistive sensor, is usually integrated into the steering wheel rim, which reacts to contact with the steering wheel rim.

[0007] In a driving system with hands-free driving capability, one or more hands-free safety mechanisms can be incorporated to ensure automatic lateral guidance during hands-free driving. These mechanisms assume the driver is no longer holding the steering wheel and therefore cannot intervene immediately in the event of a malfunction in automatic lateral guidance. Consequently, for example, the target signals (e.g., target curvature signals, target steering angle signals) upon which the steering system control is based can be ensured in terms of steering amplitude and / or steering force, particularly limiting the magnitude and / or variation of these target signals over time.

[0008] When hands-free driving is used, the hands-free safety mechanism is usually activated. If the hands-free driving function is deactivated and no longer used because another driving function is engaged (e.g., activated by the driver through an operation, or by the driving system, such as when a safety driving function is activated in a dangerous situation), then these hands-free safety mechanisms should be deactivated. The hands-free safety mechanism thus acts as an obstacle to taking over driving functions. This also applies if the hands-free driving function is deactivated without activating other driving functions (e.g., due to steering system failure and / or due to proper driver operation), because the hands-free safety mechanism interferes with manual driving operation. Summary of the Invention

[0009] The purpose of this invention is to improve the safety of the driving system when the driving function is disabled.

[0010] This objective is achieved through the features of the independent patent claim. Advantageous embodiments are described in the dependent claims. It should be noted that additional features of a claim dependent on the independent claim, in the absence of features of the independent claim or in combination with only a subset of features of the independent claim, can form an independent invention independent of all combinations of features of the independent claim, which can be the subject of the independent claim, divisional application, or subsequent application. This also applies to the technical teachings described in the specification, which can form an invention independent of the features of the independent patent claim.

[0011] A first aspect of the invention relates to a driving system for a motor vehicle with a steering wheel, having a hands-free driving function for automated driving, wherein the hands-free driving function, when activated, allows hands-free driving operation with at least automatic lateral guidance without the driver touching the steering wheel. Therefore, during hands-free driving operation, the vehicle can operate continuously without contact with the steering wheel. The hands-free driving function is, for example, a Level 2+ driving function. However, it is also conceivable that the hands-free driving function is an SAE Level 3 driving function. The driving system preferably includes several driving functions with different degrees of automation for automated driving, such as SAE Level 1 and SAE Level 2 as hands-free driving functions and SAE Level 2+ as hands-free driving functions.

[0012] During automatic lateral guidance, the controllable electric steering system can be controlled based on a target signal upon which the control is based. The steering system is, for example, an electrically driven power steering system (e.g., EPS - Electric Power Steering, EPAS - Electric Power Assisted Steering, or EHPS - Electro-hydraulic Power Steering). Electrical control signals used to directly control the steering system (e.g., a steering angle target signal specifying the steering angle to be set) correspond directly to, or are determined based on, a target signal generated by the driving system (e.g., a curvature target signal specifying the target curvature of the trajectory driven by the driving function).

[0013] The driving system includes a hand-holding recognition device for recognizing the driver's touch of the steering wheel. This hand-holding recognition device may include, for example, a sensor system (e.g., capacitive or resistive) integrated into the steering wheel rim that reacts to touch of the steering wheel rim. However, the term "hand-holding recognition device" can also include implementations that confirm touch of the steering wheel by detecting specific steering inputs (e.g., steering torque) applied by the driver, without integrating a dedicated sensor system for hand-holding recognition into the steering wheel itself.

[0014] In addition, one or more hands-free safety mechanisms are provided to ensure automatic lateral guidance during hands-free driving operations. For example, a first hands-free safety mechanism ensures the target signal on which the steering system control is based. The first hands-free safety mechanism can, for example, ensure the target signal (e.g., curvature target signal, steering angle target signal) on which the steering system control is based in terms of steering amplitude and / or steering force, and in particular, can limit the magnitude of the target signal and / or the change of the target signal over time.

[0015] The system is configured to perform the various activities described below. This is typically accomplished using one or more software-controlled devices, particularly electronic controllers. Each of the one or more software-controlled devices may include one or more programmable processors that operate under program control via one or more software programs in a manner consistent with the present invention. The aforementioned one or more release safety mechanisms are also preferably implemented using software.

[0016] When necessary, the driving system is set to disable the hands-free driving function without disabling one or more hands-free safety mechanisms, and to keep one or more hands-free safety mechanisms active. The hands-free driving function may be automatically disabled (e.g., when another driving function disables hands-free driving) or disabled in response to driver input (e.g., when the driver touches an operating component to disable the hands-free driving function or activate a driving function that replaces the hands-free driving function).

[0017] It should be noted that special system states can be envisioned, in which (unlike the deactivation of the hands-free driving function according to the invention described above without disabling one or more hands-free safety mechanisms), one or more hands-free safety mechanisms are immediately deactivated upon deactivation of the hands-free driving function. Furthermore, it should be noted that there may be other hands-free safety mechanisms in the driving system, which typically behave differently from the hands-free safety mechanisms discussed within the scope of this invention.

[0018] The driving system is preferably configured to indicate, via appropriate signals (e.g., optically, acoustically, and / or tactilely) that the hands should be gripping the steering wheel again before or as the hands-free driving function is deactivated.

[0019] After the hands-free driving function is deactivated (especially after the hands-free driving function is deactivated), a handheld recognition device is used to confirm that the driver has touched the steering wheel in response to the corresponding instruction.

[0020] One or more hands-free safety mechanisms are also deactivated only after it is confirmed that the driver has touched the steering wheel (again). For example, it is stipulated that, in response to a logical AND link, deactivating the hands-free safety mechanism disables the hands-free driving function. and The driver touched the steering wheel again.

[0021] Therefore, the hands-free driving function can be immediately deactivated; however, one or more associated hands-free safety mechanisms are only deactivated after the driver has taken over steering (hands-free). This ensures the controllability and safety of function deactivation or switching.

[0022] For example, in the first application scenario of the invention, the driving system includes not only the hands-free driving function but also another driver assistance function, particularly a handheld driver assistance function with handheld driving operation. The other driver assistance function is preferably one that requires a larger maximum steering angle and / or higher maximum steering force compared to the hands-free driving function (not considering hands-free safety mechanisms that limit steering angle and / or steering force). Preferably, the driving system is configured to deactivate the hands-free driving function to activate the other driver assistance function, wherein the hands-free safety mechanism is only deactivated in response to confirmation that the driver has touched the steering wheel, and a potentially larger maximum steering angle and / or higher maximum steering force may be effective when the hands-free safety mechanism is deactivated. Therefore, if the hands-free driving function is deactivated, for example, due to the activation of another driver assistance function (e.g., initiated by the driver through an operational action or by the driving system itself, e.g., when the driver assistance function is automatically activated in a dangerous situation), the hands-free safety mechanism remains activated until the driver is detected touching the steering wheel again.

[0023] For example, a first hands-free safety mechanism is configured as a target signal protection block with protective functions to protect the target signal during hands-free driving operations, based on which the steering system control is performed. The target signal protection block is preferably implemented in software. The target signal protection block receives the target signal to be protected (e.g., a curvature target signal) on the input side and outputs the protected target signal (e.g., a curvature target signal) on the output side. The target signal protection block is configured, for example, to protect the target signal in terms of steering amplitude and / or steering force, particularly limiting the magnitude of the target signal and / or its variation over time (e.g., in the case of a curvature target signal).

[0024] In addition, the target signal protection block receives a hand-held status signal indicating that the driver's touch of the steering wheel has been detected by the hand-held recognition device. The target signal protection block is designed to deactivate the protection function in response to confirmation of the driver's touch of the steering wheel by means of a changing hand-held status signal, so that the target signal output on the output side is no longer protected by the protection function, thus deactivating the first hands-free safety mechanism.

[0025] In a second application scenario of the invention, for example, if the hands-free driving function is deactivated due to a steering system malfunction, the hands-free safety mechanism remains active until the driver is detected touching the steering wheel again. When the hands-free driving function is initially activated, it is therefore deactivated in response to an error in the steering system, but the hands-free safety mechanism remains activated.

[0026] It can be stipulated that a hands-free safety mechanism on the steering system side is set up, which is activated or deactivated by the driving system according to the mode signal. If the mode signal indicates hands-free driving operation, the hands-free safety mechanism on the steering system side is activated. If the mode signal does not indicate hands-free driving operation, the hands-free safety mechanism on the steering system side is not activated. In this case, the driving system preferably includes a safety block as an additional hands-free safety mechanism, which works in conjunction with the hands-free safety mechanism on the steering system side, and receives the mode signal on the input side on the input side and outputs the mode signal on the output side on the output side. The steering system receives the mode signal on the output side, wherein the third hands-free safety mechanism on the steering system side is deactivated when the output side mode signal indicates hands-free mode and when the output side mode signal does not indicate hands-free mode. The safety block also receives a hands-free status signal indicating that the driver has touched the steering wheel. When the input side mode signal does not indicate hands-free mode, the target signal safety block only responds to the confirmation that the driver has touched the steering wheel by switching the output side mode signal to an output side mode signal that does not indicate hands-free mode by means of a changed hands-free status signal. This corresponds to the deactivation of the second hands-free safety mechanism, as it now forwards the modified mode signal to the steering system. This causes the hands-free safety mechanism on the steering system side to deactivate. Through the above interaction, it is ensured that the hands-free safety mechanism on the steering system side is only deactivated after the steering wheel is touched. This, for example, prevents the hands-free driving function from being deactivated due to a steering system malfunction, from failing to immediately deactivate the steering system-side hands-free safety mechanism.

[0027] A second aspect of the invention relates to an autonomous driving method for a motor vehicle with a steering wheel, wherein a hands-free driving function, when activated, allows at least automatically lateral guidance for hands-free driving operation without the driver touching the steering wheel, and during automatic lateral guidance, a controllable steering system can be controlled by a target signal. The method includes the following steps:

[0028] - Operate the hands-free driving function when one or more hands-free safety mechanisms are activated to ensure automatic lateral guidance during hands-free driving operation;

[0029] - Disable hands-free driving function without disabling one or more hands-free safety mechanisms;

[0030] - Confirm that the driver is touching the steering wheel; and

[0031] - In response to confirmation that the driver has touched the steering wheel, deactivate one or more hands-free safety mechanisms.

[0032] The foregoing statements regarding the driving system according to the first aspect of the invention are also applicable in a corresponding manner to the method according to the second aspect of the invention. Advantageous embodiments of the method according to the invention, not explicitly described herein or in the claims, correspond to the advantageous embodiments of the driving system according to the invention described above or in the claims.

[0033] A third aspect of the invention relates to software having program code for executing the method according to a second aspect of the invention when the software is run on one or more software-controlled devices. The software-controlled device preferably includes one or more programmable processors that process the program code of the software loaded into working memory. Attached Figure Description

[0034] The present invention will now be explained with reference to the embodiments and the accompanying drawings.

[0035] Figure 1 An exemplary electronic control unit for autonomous driving is shown, which receives environmental and operational information and controls other functional units;

[0036] Figure 2 An embodiment of an electronic control unit for autonomous driving is shown; and

[0037] Figure 3 It shows Figure 2 The exemplary working method of the embodiments shown is as follows. Detailed Implementation

[0038] Figure 1 A driving system for autonomous driving is shown, which has an electronic control unit (AF-ECU) for autonomous driving, which receives environmental and operational information and controls functional units.

[0039] Environmental information from ambient sensors F-US, L-US, R-US, and H-US is received by the electronic control unit (AF-ECU) for autonomous driving. The AF-ECU is connected to the control unit HU and is used to output information to the driver (e.g., via a screen) and to receive operational input. The AF-ECU controls the transmission control unit (EGS), the electric steering system control unit (EPS), and the vehicle drive control unit (DME). Furthermore, a hand gesture recognition device (HO) is provided to detect driver touch on the steering wheel, generating a hand gesture status signal (S-HO) indicating steering wheel touch. This signal is forwarded to the AF-ECU via the control unit HU.

[0040] Figure 2 An exemplary implementation of the driving system according to the invention is shown. The blocks shown within the control unit AF-ECU are preferably functional blocks implemented in software running on one or more processors within the control unit AF-ECU. The main controller FM is specifically used to activate and deactivate driving functions supported by the driving system for autonomous driving, particularly to activate and deactivate hands-free driving functions (e.g., Level 2+) for autonomous driving, and to control the path planning BP. The path planning BP generates a trajectory signal T, which describes the trajectory to be traveled. Furthermore, the path planner BP outputs a control mode signal RM based on the driving function selected by the main controller. The control mode signal RM indicates whether the main controller FM has selected hands-free driving operation (i.e., active hands-free driving function, e.g., Level 2+). In addition, a controller R is configured to generate a target curvature signal K, which describes the target curvature of the trajectory to be traveled, taking into account the trajectory signal T.

[0041] Furthermore, as the first hands-free safety mechanism, a target signal protection block SM1 is provided with a protection function to ensure the target curvature signal K. This block receives the target curvature signal K to be protected on the input side and outputs the protected target curvature signal K' on the output side. During hands-free driving operation (indicated by the control mode signal RM), the protection function ensures the target curvature signal. Through the protection function of the target signal protection block SM1, when the hands-free driving function is activated, the target curvature signal K is ensured in terms of steering amplitude and / or steering force by limiting the magnitude of the target signal and / or its variation over time. Additionally, the target signal protection block SM1 also receives a hand position status signal S-HO, indicating that the driver's touch on the steering wheel has been recognized by the hand position recognition device HO. When hands-free driving operation is discontinued, the protection function can be deactivated in response to the confirmation (via the hand position status signal S-HO) that the driver has touched the steering wheel, so that the target signal output on the output side, i.e., the target curvature signal K', is no longer protected by the protection function and corresponds to the target curvature signal K. There is also a lateral guidance vehicle controller FR, which receives the (protected) target curvature signal K', reacts to interference signals (such as crosswinds), and outputs the resulting target steering angle signal LW. The target steering angle signal LW is received as a target signal by the steering control unit EPS of the electric power steering system.

[0042] Furthermore, a second hands-free safety mechanism SM2 is installed in the controller AF-ECU, which controls the hands-free safety mechanism SM3 on the steering system side. The second hands-free safety mechanism SM2 receives the control mode signal RM and outputs an output-side control mode signal RM', which depends on the state of the received hands-free status signal S-HO. The second safety mechanism SM2 prevents the steering system-side hands-free safety mechanism SM3 from being immediately deactivated when the control mode signal RM switches from hands-free operation to hands-free operation. The steering control unit EPS receives the output-side control mode signal RM' and controls the state of the steering system-side hands-free safety mechanism SM3 according to the control mode signal RM': when the control mode signal RM'—which indicates the activated hands-free driving mode—is active, the steering system-side hands-free safety mechanism SM3 is activated; otherwise, it is deactivated.

[0043] Combined below Figure 3 When explaining the operation of the driving system according to the invention, it is assumed that the vehicle is initially in a hands-free driving operation with active hands-free driving function (e.g., level 2+) (see...). Figure 1 (Step 100). When hands-free driving is activated, safety mechanism SM1 is activated (controlled by control mode signal RM) and limits steering range and / or steering force. Additionally, when hands-free driving is activated, steering system-side safety mechanism SM3 is activated (controlled by control mode signal RM'). When steering system-side safety mechanism SM3 is activated, it reduces steering force, for example, in cases where the steering system malfunctions.

[0044] If the previously activated hands-free driving function for autonomous driving is deactivated via the function master controller FM (see...) Figure 3 In step 110, for example, if another driving function is activated (e.g., by the driver through an operational action, or by the driving system, such as in a dangerous situation when a safety driving function is activated), then these safety mechanisms SM1 and SM3 must be deactivated. These safety mechanisms thus act as barriers to taking over driving functions. The same applies if the hands-free driving function is deactivated without the activation of other driving functions (e.g., due to a malfunction in the steering system and / or through appropriate driver operation), because these safety mechanisms SM1 and SM3 affect manual driving operation.

[0045] However, during the process of disabling the hands-free driving function via the function master controller FM, the hands-free safety mechanisms SM1 and SM3 are not immediately deactivated after the hands-free driving function is deactivated. Instead, in query 120, it is checked whether the driver has touched the steering wheel before the hands-free driving function is deactivated or after the driver has been instructed to re-grasp the steering wheel following the deactivation of the hands-free driving function (see step 110). When the driver re-grabs the steering wheel, safety mechanisms SM1 and SM3 are deactivated in step 130.

[0046] Therefore in Figure 1 Within the target signal protection block SM1, the safety function for limiting steering range and / or steering force is cut off only when the hand-held status signal S-HO switches and indicates that the steering wheel is being held (even though the control mode signal RM is present, which indicates hand-held driving operation).

[0047] However, after the hands-free driving function is switched to hands-free mode by disabling the control mode signal RM, safety mechanism SM2 initially remains active, causing the output-side control mode signal RM' to remain in hands-free mode (despite the switch in control mode signal RM). Only when the hands-free status signal S-HO is also switched to indicate that the steering wheel is being gripped, safety mechanism SM2 is also deactivated, and the output-side control mode signal RM' is switched to hands-free mode at the output of safety mechanism SM2. In response to the switch in control mode signal RM', safety mechanism SM3 on the steering system side is deactivated.

[0048] In the first exemplary scenario, during active hands-free driving operation, one hands-free driving function is disengaged due to another driving function requiring greater steering force. In this case, the hands-free safety mechanism remains active until the driver grips the steering wheel and, in response, disengages the hands-free safety mechanism.

[0049] In the second exemplary scenario, during the activation of hands-free driving operation, an error occurs in the steering system, such as an incorrect steering intervention. The steering control unit EPS of the steering system, by monitoring the steering torque, mistakenly identifies this incorrect steering intervention as driver intervention. The steering system EPS transmits the alleged driver-side steering intervention to the function master controller FM, which causes the previously activated hands-free driving function to be disconnected (because the function master controller FM originates from the driver's intervention). As a result, the control mode switches from hands-free mode to hands-free mode, and the control mode signal RM switches accordingly at the input of safety function SM2. Without safety function SM2, the steering system would immediately receive information about the change in control mode upon disconnection and would deactivate safety function SM3 in the steering control unit EPS of the steering system. With safety function SM2, when the control mode signal RM switches from hands-free mode to hands-free mode, the control mode signal RM' at the output of the safety function does not switch immediately, so safety function SM3 remains active in the steering system. Safety function SM1 also remains active. Safety mechanism SM2 is only deactivated when the steering wheel is gripped and the hand-held state signal S-HO is switched, causing the control mode signal RM' at the safety mechanism output to switch to hand-held state. In response, safety function SM3 in the steering control unit EPS of the steering system is also deactivated. Furthermore, safety mechanism SM1 is subsequently deactivated as well.

Claims

1. A driving system (AF-ECU) for a motor vehicle with a steering wheel, having a hands-free driving function for automated driving, wherein, The hands-free driving function, when activated, allows for at least automatic lateral guidance during hands-free driving without the driver touching the steering wheel. During this automatic lateral guidance, a controllable steering system (EPS) can be controlled based on target signals (K, K'), and the driving system is used to generate these target signals, wherein: - A handheld recognition device (HO) for recognizing the driver's touch of the steering wheel; and - One or more hands-free safety mechanisms (SM1-3) to ensure the automatic lateral guidance during hands-free driving operations. And the driving system is configured as follows: - Disable the hands-free driving function, but not at least one of the hands-free safety mechanisms (SM1-3). - Confirm that the driver is touching the steering wheel; and - In response to confirmation that the driver has touched the steering wheel, one or more of the hands-free safety mechanisms (SM1-3) are also deactivated. The target signals (K, K') mentioned therein relate to target curvature signals or target steering angle signals.

2. The driving system according to claim 1, wherein, - As the first hands-free safety mechanism in the driving system, a target signal protection block (SM1) with a protection function is provided during hands-free driving operation to protect the target signals (K, K') on which the steering system control is based. The target signal protection block receives the target signal (K) to be protected on the input side and outputs the target signal (K') protected by the protection function on the output side. - The target signal protection block (SM1) also receives a handheld status signal (S-HO), which indicates that the handheld recognition device (HO) has identified that the driver is touching the steering wheel, and - The target signal protection block (SM1) deactivates the protection function in response to confirmation that the driver touches the steering wheel by means of a changing hand position signal (S-HO), so that the target signal output on the output side is no longer protected by the protection function.

3. The driving system according to claim 1, wherein, The first hands-free safety mechanism is designed to ensure that the control of the steering system is based on the target signal (K, K') in terms of steering amplitude and / or steering force.

4. The driving system according to claim 3, wherein, The first hands-free safety mechanism is designed to limit the magnitude of the target signal (K, K') and / or the change of the target signal (K, K') over time in terms of steering amplitude and / or steering force.

5. The driving system according to any one of claims 1 to 3, wherein, In addition to the hands-free driving function, the driving system also includes other driver assistance functions, and the driving system is configured to deactivate the hands-free driving function to activate the other driver assistance functions, wherein one or more of the hands-free safety mechanisms (SM1-3) are deactivated only in response to confirmation that the driver touches the steering wheel.

6. The driving system according to claim 5, wherein, The additional driver assistance function is a handheld driver assistance function with handheld driving operation.

7. The driving system according to claim 5, wherein, Compared to hands-free driving, the additional driver assistance features require a greater maximum steering angle and / or greater maximum steering force.

8. The driving system according to any one of claims 1 to 3, wherein, The driving system is configured to deactivate the hands-free driving function in response to an error in the steering system when the hands-free driving function is initially activated, rather than immediately deactivating one or more of the hands-free safety mechanisms (SM1-3).

9. The driving system according to any one of claims 1 to 3, wherein, - Configure a protection block (SM2) that receives the input mode signal (RM) on the input side and outputs the output mode signal (RM') on the output side. - The steering system receives the mode signal (RM') from the output side, and the hands-free safety mechanism (SM3) on the steering system side is activated when the mode signal (RM') on the output side indicates hands-free mode, and deactivated when the mode signal (RM') on the output side does not indicate hands-free mode. - The protective block (SM2) also receives a hand-held status signal (S-HO), which indicates that the driver is touching the steering wheel, and - The protection block (SM2) is configured to, when the input-side mode signal (RM) does not indicate the hands-free mode, only in response to confirmation that the driver touches the steering wheel by means of the modified hand-holding status signal (S-HO), switch the output-side mode signal (RM') to the output-side mode signal (RM') that does not indicate the hands-free mode, thereby disabling the hands-free safety mechanism (SM3) on the steering system side.

10. The driving system according to any one of claims 1 to 3, wherein, The driving system is configured to instruct the driver to take the steering wheel back in place before or after the hands-free driving function is deactivated.

11. A method for automating a motor vehicle with a steering wheel, wherein, The hands-free driving function, when activated, allows at least automatic lateral guidance for hands-free driving without the driver touching the steering wheel, and during the automatic lateral guidance, the controllable steering system (EPS) can be controlled according to the target signals (K, K') upon which the control is based, and the method includes the following steps: - The hands-free driving function is operated when one or more hands-free safety mechanisms (SM1-3) are activated to ensure the automatic lateral guidance during the hands-free driving operation; - Disable the hands-free driving function, but not disable one or more of the hands-free safety mechanisms (SM1-3). - Confirm that the driver is touching the steering wheel; and - In response to confirmation that the driver is touching the steering wheel, deactivate one or more of the hands-free safety mechanisms (SM1-3). The target signals (K, K') mentioned therein relate to target curvature signals or target steering angle signals.

12. A computer-readable storage medium having program code stored thereon, the program code executing the method according to claim 11 when run on one or more computer-controlled devices.

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