Driver assistance system

Abstract

A driver assistance system (1) comprises: at least one sensor device (2) for detecting an actual or imminent collision of an object with the windshield of a motor vehicle; a vehicle steering system (4) configured to translate a steering command applied by the driver to a steering handle (5) of the same into a steering angle at the wheel; and a control unit (3) for receiving and processing signals from the at least one sensor device (2) and for controlling the vehicle steering system (4) based on said signals. The control unit (3) is configured with respect to controlling the vehicle steering system (4) such that, upon detection of an actual or imminent collision, the position of the steering handle (5) of the vehicle steering system is temporarily stabilized. In particular, the steering can be temporarily made intentionally stiffer.

Description

[0001] The invention relates to a driver assistance system with the features of the preamble of claim 1.

[0002] Collisions between objects and the windshield of a motor vehicle, be they stones, animals, or other objects, are not only capable of causing damage. Rather, the driver can be startled at the moment of impact and thus be prompted to unintentionally operate the steering wheel. Smaller objects, in particular, are often only perceived audibly at the moment of impact, so the driver cannot prepare for such a collision, and the shock of the impact noise is therefore very sudden and unexpected. Unintentional steering wheel movements often pose a danger that can be more serious than a collision with an object that, while audibly noticeable, is still within the windshield's capacity to withstand. The present invention aims to reduce such a danger.

[0003] Driver assistance systems with the features of the preamble of claim 1 are equally known from DE 10 2020 005 472 A1, DE 10 2018 100 899 A1 and DE 10 2018 207 222 A1.

[0004] From DE 10 2020 005 472 A1, a method for environmental sensing with regard to rockfall, a control device for carrying out such a method, and a corresponding detection device are known in this context. Suitable sensors mentioned include a lidar system, a radar system, a monocular camera, and a stereogrammetric camera system. At least two measurements are taken with these sensors to detect potential collision objects. The trajectory of the detected object is calculated from these two measurements. Based on the trajectory of the detected object, it is classified so that at least one countermeasure can then be taken.According to DE 10 2020 005 472 A1, at least one countermeasure is selected from a group consisting of an evasive maneuver, a braking maneuver, an acceleration maneuver, and an active defensive maneuver, the latter involving the activation of a defensive device similar to a windshield wiper. The objective in DE 10 2020 005 472 A1 is to avoid the collision.

[0005] Another driver assistance system, which aims to avoid collisions with an object on the windshield of an autonomous vehicle, is known from DE 10 2018 100 899 A1. A pressure sensor integrated into the windshield is proposed as the sensor technology. The pressure sensor can, in particular, comprise a multitude of piezoelectric thin-film sensors laminated into a multi-layered windshield. A signal from the pressure sensor is used to identify an impact on the windshield as a stone chip. In response to an identified stone chip, a truck ahead is identified that is within a predefined radius of the vehicle, whereupon the vehicle is instructed to perform an evasive maneuver.Since DE 10 2018 100 899 A1 primarily concerns an evasive maneuver during autonomous driving, the startle for the driver is indeed disturbing, but generally unproblematic for driving safety, as no unintentional steering movement can result from it.

[0006] A discussion of the problem of startling the driver can be found in DE 10 2018 207 222 A1 concerning the reduction of the effect of a startle reaction of a driver of a motor vehicle.A driver assistance system is proposed that is designed to detect a sudden disturbance triggering a startle response, to detect at least one steering wheel size characteristic of a steering movement by the driver on the steering wheel of the motor vehicle within a predetermined time window after the disturbance, to determine or receive a first steering angle of one wheel of the motor vehicle corresponding to the steering wheel size, which is independent of the disturbance, to determine a second steering angle of the wheel corresponding to the steering wheel size, which is dependent on the disturbance and in which the influence of the steering wheel size on the steering angle of the wheel is less than in the first steering angle, and to steer at least one wheel according to the second steering angle. A tire blowout and a stone impact are mentioned as examples of disturbances.The proposed compensation measure in DE 10 2018 207 222 A1 consists of allowing the unintentional steering movement, but reducing its effect on the steering angle of the wheels. In the context of power steering, this is achieved by generating a torque from the steering assistance that opposes the steering movement.

[0007] The invention is based on the objective of showing further alternatives in this regard.

[0008] For this purpose, a driver assistance system according to claim 1 is proposed, which is characterized in particular by the fact that the control unit is configured with regard to the control of the vehicle steering in such a way that, when an actual or imminent collision is detected, the position of the steering handle of the vehicle steering is temporarily stabilized.

[0009] This counteracts the driver's inadvertent steering input, making it less likely than usual that the steering handle would be adjusted if startled. This prevents abrupt maneuvers that would result from unintentional steering input. To avoid impairing vehicle control, this steering handle stabilization is only temporary, lasting only a short period.

[0010] Specific embodiments of the invention are the subject of further patent claims.

[0011] In particular, the temporary stabilization of the vehicle's steering can involve briefly imposing a degree of resistance, thereby reliably preventing the driver from jerking the steering wheel in a moment of shock. The degree of this desired resistance is preferably chosen so that the driver can overcome it. However, the force required for this is greater than that required to operate the steering without the artificially induced resistance.

[0012] In one particular design, the steering assistance can be reduced for temporary stabilization. This increases the resistance at the steering handle for the driver.

[0013] Furthermore, the steering ratio can also be increased for temporary stabilization. In this context, the steering ratio is understood as the relationship between the steering input travel at the steering handle and the steering angle at the vehicle wheels. This also increases the resistance at the steering handle for the driver.

[0014] According to another special design, an additional mechanical damping device can be provided on the steering system. This is activated for temporary stabilization, thus generating mechanical resistance against the movement of the steering handle.

[0015] The temporary stabilization preferably occurs for a predetermined time interval. This time interval is preferably limited to 0.5 to 2 seconds, so that the driver regains the normal steering feel afterward. It has been shown that unintentional startle reactions are generally no longer to be expected after such a time interval. Steering stiffness preferably remains limited to the specified time interval in order to avoid unintentional steering reactions.

[0016] Furthermore, the degree of temporary stabilization during the time interval can be reduced towards the end of the interval. This achieves a smooth return to the usual steering feel. The stabilization can be reduced continuously or gradually.

[0017] According to another specific embodiment, a time delay interval can be provided between the actual or predicted time of the collision and the start of temporary stabilization, before the steering handle is stabilized. This allows the period during which the temporary stabilization of the steering handle occurs to be kept as short as possible. This approach takes advantage of the fact that a driver's reaction to a sudden disturbance occurs only after a certain delay, so that at the moment of collision, the driver can still reproduce a steering command that corresponds to their perception at a time before the disturbance was perceived, usually fractions of a second. The time delay interval is preferably chosen to be in the range of 0.2 to 0.8 seconds.

[0018] To detect the disturbance event, the at least one sensor device preferably comprises one or more of the following: a pressure sensor, a vibration sensor, a camera, a radar system and / or a lidar system.

[0019] The invention will now be explained in more detail with reference to an embodiment illustrated in the drawing. The drawing shows: Fig. 1 a schematic view of an exemplary embodiment of a driver assistance system within a motor vehicle, Fig. Two different procedures for the temporary stabilization of the steering handle, and in Fig. 3. A block diagram to illustrate the logic of the driver assistance system.

[0020] The exemplary embodiment shows in Fig. 1 a motor vehicle, in particular a passenger car or light commercial vehicle, in which a driver assistance system 1 of the type described in more detail below is implemented.

[0021] The driver assistance system 1 is designed to prevent or at least mitigate unintentional steering commands by a driver which may be caused by the driver being startled by a collision of an object with the windshield of the motor vehicle.

[0022] The in Fig. The driver assistance system 1 shown accordingly comprises at least one sensor device 2 for detecting an actual or imminent collision of an object with a windshield of the motor vehicle.

[0023] The at least one sensor device 2 can, for example, include a vibration sensor which is arranged and configured in such a way as to detect the impact of a foreign object, for example a stone, and to generate a corresponding signal.

[0024] Alternatively, a pressure sensor as described in DE 10 2018 100 899 A1 can be used.

[0025] Furthermore, it is possible to use camera-based systems, a radar system, or a lidar system, as described in DE 10 2020 005 472 A1, to detect a collision. With such systems, it is not only possible to detect an actual collision, but also to predict an imminent collision and its time.

[0026] Furthermore, the aforementioned sensor devices can be combined with each other.

[0027] The relevant sensor signals are transmitted to a control unit 3, which, among other things, serves to control a vehicle steering system 4. The control unit 3 is designed and configured to receive and process the signals from the at least one sensor unit 2.

[0028] The vehicle steering system 4 is designed and equipped to translate a steering command applied on the driver's side to a steering handle 5, for example a steering wheel, into a steering wheel angle on the wheel side.

[0029] The steering command can be detected, for example, by means of sensors 6 located near the steering mechanism. In the case of a steering wheel, this can include, for example, the steering angle and / or the steering torque applied by the driver. Optionally, mathematical derivatives of the aforementioned quantities with respect to time can also be taken into account.

[0030] The conversion of the steering command into a steering angle at the vehicle wheels 7 can be carried out in a conventional manner by means of a steering gear 8 with steering assistance 9 or by means of a steer-by-wire steering system.

[0031] If the control unit 3 detects an actual collision of the windshield with an object based on the signals from the at least one sensor unit 2, or if the sensor signals indicate that such a collision is imminent, possibly also determining the time of the collision, the position of the steering handle 5 is temporarily stabilized by appropriately controlling the vehicle steering 4 in order to avoid any unintentional jerky steering movements by the driver and thereby reduce the risk of an accident.

[0032] The stabilization of the steering handle 5 can preferably be achieved by activating a temporary stiffness in the steering handle 5. In such a situation, the driver must exert increased force compared to normal operation of the vehicle steering 4 to move the steering handle 5 from its current position. This physical resistance reduces the application of unintended steering commands by the driver.

[0033] Furthermore, the steering assistance of the vehicle steering 4 can be reduced to temporarily stabilize the steering handle 5.

[0034] Alternatively or additionally, the steering ratio of the vehicle steering system 4 can be increased for temporary stabilization.

[0035] Furthermore, it is possible to provide an additional damping device 10 on the vehicle steering system 4, which, when activated, increases the resistance when operating the steering handle 5. For temporary stabilization, this additional damping device 10 is activated by the control unit 3, thus generating mechanical resistance to the movement of the steering handle 5.

[0036] The temporary stabilization preferably occurs briefly for a predetermined time interval, which can range from 0.5 to 2 seconds. Afterwards, the stabilization is withdrawn, so that the driver regains the usual normal steering feel of the vehicle's steering system.

[0037] In one modification, the degree of temporary stabilization during the time interval can be reduced towards the end of the interval to create a smoother transition back to the familiar feel of the vehicle's steering. The stabilization can be reduced continuously or in stages from a certain point in the interval, as described in Fig. 2 is shown as an example.

[0038] Furthermore, a time delay interval can be provided between the actual time t0 of the collision or the predicted time t0* of the collision and the start t1 of temporary stabilization, before the steering handle 5 is stabilized. The time delay interval is preferably 0.2 to 0.8 seconds.

[0039] Fig. Figure 2a shows an example of a possible process for temporary stabilization. Assume that at time t0 an object collides with the windshield and is detected by the sensor device 2. After the time delay interval has elapsed, at time t1, temporary stabilization of the steering handle 5 is carried out, for example by making it more difficult for the driver to operate it. The extent of this temporary stabilization can be set for an entire time interval, in Fig. 2a is maintained at a constant level until time t2. At the end of the time interval, the temporary stabilization is completely withdrawn. However, it is also possible to continuously reduce the degree of stabilization at a point between t1 and t2, namely at time t3, until the end of the time interval to achieve a smoother transition to normal operation. This is particularly advantageous if the driver actually intended to make an unintentional steering movement. Without a smooth phase-out of the stabilization, the driver would then feel a change in the resistance of the steering handle at the end of the time interval, which could lead to further confusion. Such confusion is avoided by reducing the degree of stabilization towards the end of the time interval.

[0040] In a variation of Fig. 2a. The reversal of stabilization from time t3 can also be carried out gradually, as in Fig. 2b shows that the gradation can be chosen so that it is not noticeable or barely noticeable to the driver. However, a certain degree of perceptibility, for example in the form of a vibration, can certainly be helpful at this point to draw the driver's attention to the specific situation.

[0041] In the Fig. 2a and Fig. 2b The reversal of the temporary stabilization after a plateau phase begins at a time after t1. Fig. 2c shows, using a further example, the possibility of starting the reversal of the temporary stabilization as early as time t1.

[0042] The logic sequence of the driver assistance system 1 described above can be understood from the block diagram according to Fig. 3.

[0043] With the initialization of the system in step S1, the control unit 3 preferably continuously monitors the sensor signals of the sensor device 2 with regard to the occurrence or imminent occurrence of a collision of an object with the windshield of the motor vehicle (step S2).

[0044] In the case of a positive outcome in step S2, the control unit 3, in a further step S3, causes the vehicle steering 4 to temporarily stabilize the steering handle 5 in the manner described above. After a corresponding time interval, the routine returns to monitoring the sensor signals. The same applies in the case of a negative outcome in step S2.

[0045] The driver assistance system described above can, in the simplest case, be implemented practically without additional components using software technology and therefore cost-effectively, provided that existing sensors on the vehicle can be used for other purposes, in order to achieve an additional safety benefit.

[0046] In principle, the startling noise caused by the impact of a stone or similar object can be reduced by applying films to the windshield of vehicles. However, applying such films is more complex than, for example, installing or embedding pressure and / or vibration sensors on a windshield.

[0047] The invention has been explained in more detail above with reference to exemplary embodiments and further modifications. In particular, individual technical features, which were explained above in the context of further individual features, can be implemented independently of these features and in combination with further individual features, even if this is not expressly described, as long as this is technically possible. The invention is therefore expressly not limited to the described exemplary embodiments and modifications, but includes in particular all embodiments defined by the claims. Reference symbol list 1 Driver assistance system 2 Sensor device 3 Control unit 4 Vehicle steering 5 Steering handle 6 Sensor 7 vehicle wheel 8 Steering gear 9 Steering assistance 10 Damping device t0 Collision time t0* Collision time, predicted t1 Start of temporary stabilization t2 End of temporary stabilization t3 Beginning of the reduction of temporary stabilization S1 Step 1 S2 Step 2 S3 Step 3

Claims

[1] Driver assistance system (1), comprising at least one sensor device (2) for detecting an actual or impending collision of an object with a windscreen of a motor vehicle, a vehicle steering system (4) which is designed to convert a steering command applied by the driver to a steering handle (5) of the same into a steering angle on the wheel side, and a control device (3) for receiving and processing signals from the at least one sensor device (2) and for controlling the vehicle steering system (4) in dependence on said signals, characterized by , that the control device (3) is configured with respect to the control of the vehicle steering (4) such that upon detection of an actual or impending collision, the position of the steering handle (5) of the vehicle steering is temporarily stabilized. [2] Driver assistance system (1) according to claim 1, characterized bythat the temporary stabilization of the vehicle steering (4) involves imposing a stiffness. [3] Driver assistance system (1) according to claim 1 or 2, characterized by that for temporary stabilization, steering assistance of the vehicle steering (4) is reduced. [4] Driver assistance system (1) according to one of claims 1 to 3, characterized by that a steering ratio of the vehicle steering (4) is increased for temporary stabilization. [5] Driver assistance system (1) according to one of claims 1 to 4, characterized by that for temporary stabilization a damping device (10) is activated, which mechanically generates a resistance against the movement of the steering handle (5). [6] Driver assistance system (1) according to one of claims 1 to 5, characterized by that the temporary stabilization occurs for a given time interval. [7] Driver assistance system (1) according to claim 6, characterized bythat the specified time interval is 0.5 to 2 seconds. [8] Driver assistance system (1) according to claim 6 or 7, characterized by that the extent of temporary stabilization during the time interval is reduced towards the end of the time interval. [9] Driver assistance system (1) according to one of claims 1 to 8, characterized by that between the actual time (t0) of the collision or the predicted time (t0*) of the collision and a start of the temporary stabilization (t1) a time delay interval is provided before the steering handle (5) is stabilized, wherein the time delay interval is preferably 0.2 to 0.8 seconds. [10] Driver assistance system (1) according to one of claims 1 to 9, characterized by that the at least one sensor device (2) comprises one or more of the following: a pressure sensor, a vibration sensor, a camera, a radar system and / or a lidar system.

Images