Driver assistance system

Abstract

Driver assistance system with at least one function module by which a counter-steering torque (ML) is applied to the steering wheel of a motor vehicle (F1) depending on defined parameters (d) and depending on defined situations (S1, S2) of different levels of danger, with at least one electronic control unit and with sensors by which the control unit queries the parameters (d) and the situations (S1, S2) of different levels of danger, wherein in the electronic control unit a specific characteristic curve (K1, K2) of the counter-steering torque is specified for each defined situation (S1, S2) or all situations (S1, S2) of the same level of danger depending on at least one parameter (d) to be taken into account for all situations (S1, S2), characterized in that For situations (S1, S2) of two levels of danger, a specific characteristic course (K1, K2) is specified for each level of danger, whereby the courses (K1, K2) behave in essentially opposite directions.

Description

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

[0002] Driver assistance systems for motor vehicles are known that include at least one primary function module for lane keeping (lane keeping assist) and a secondary function module for preventing collisions during lane changes (lane change assist). Depending on defined parameters, in particular the current distance of the vehicle from the lane markings that laterally define its lane and / or the speed at which the vehicle approaches a lane marking, and depending on defined situations of varying severity, a counter-steering torque is applied to the steering wheel or the wheels. Alternatively, the counter-steering torque can also be applied by individual wheel braking or by other interventions in the steering system.

[0003] The known driver assistance systems have at least one electronic control unit and sensors through which the control unit queries parameters and situations of varying degrees of danger. For technical background, reference is made, for example, to DE 10 2005 036 219 A1, DE 10 2007 001 117 A1 and DE 10 2004 028 613 A1.

[0004] Both the lane keeping assist and the lane change assist systems use haptic feedback to the driver in the form of a (counter-)steering torque or a combination of steering torque and vibration. This is applied by an actuator on the steering system and steers the vehicle towards the center of the currently driven lane within two lane markings, or at least away from the hazard. Additionally, a vibration in the steering wheel can also be used as haptic feedback. This vibration, which occurs simultaneously with the torque, clarifies for the driver that this is system feedback and not normal road feedback. However, the vibration will not be discussed further here.

[0005] According to the current state of the art, the curves of the counter-steering torque application, independent of the current situation, depend on the parameters mentioned above and are, firstly, essentially linearly increasing, and secondly, the same for both situations or both functional modules. Therefore, the driver cannot distinguish, based solely on the applied steering torque, which situation has been detected and which functional module is active.

[0006] German patent DE 103 02 776 A1 discloses a method for generating at least one warning signal in a vehicle, describable by signal frequency and signal amplitude, for the purpose of being heeded by a driver. The signal frequency and / or the signal amplitude of the warning signal is variable during the signal duration. Furthermore, it is provided that the amplitude of the warning signal is increased at least section by section at a finite rate of change, starting from a low initial value at the beginning of signal generation.

[0007] Furthermore, DE 10 2005 037 273 A1 describes a lane departure warning system for vehicles with a detection unit for identifying lane markings detected by an environmental sensor, an estimation unit for assessing the potential hazards posed by the lane markings, and a reaction module for initiating countermeasures. Depending on the estimated hazard potential, the system determines the timing and / or intensity of these countermeasures. The detection unit for classifying the lane markings and the estimation unit for assessing the hazard potential are designed to take this classification into account.

[0008] The object of the invention is to improve a driver assistance system in terms of its clearer perceptibility to the driver.

[0009] This problem is solved by the features of claim 1. The dependent claims are advantageous embodiments of the invention.

[0010] The driver assistance system according to the invention comprises at least one functional module, e.g., a first functional module for lane keeping (lane keeping assist) and / or a second functional module for preventing a collision during a lane change (lane change assist), by which a counter-steering torque is applied to the steering wheel of a motor vehicle depending on defined parameters and depending on defined situations of varying degrees of danger. Furthermore, at least one electronic control unit and sensors are provided by which the control unit queries the parameters and the situations of varying degrees of danger. It is essential to the invention that in the electronic control unit, a specific parameter, tailored to the respective situation, is applied to each defined situation or all situations of the same degree of danger.The steering torque curve is assigned to each level of danger, whereby the parameter(s) of the (counter-)steering torque curves is (or are) the same for all situations. For situations with two levels of danger, a specific characteristic curve is defined for each level, with the curves essentially being opposite in direction.

[0011] Preferably, within the defined characteristic profiles, at least one portion of each profile is provided with a gradient steeper than the rest of the profile. The steeper gradient is of crucial importance for subjective perception.

[0012] A parameter to be considered in all situations is preferably the distance of the vehicle to a lane marking, particularly one directly adjacent to the oncoming lane, or to the edge of the road. However, another parameter to be considered in all situations could also be (additionally) the speed at which the vehicle moves away from the center of its lane towards a lane marking, particularly one directly adjacent to the oncoming lane.

[0013] The invention allows – but does not necessarily require – a specific functional module to be assigned to each defined situation. It is less important for the driver to know which functional module is activated than to know the level of danger and how to react correctly. Furthermore, according to the invention, only a single functional module can be provided for all situations and levels of danger.

[0014] According to the invention, firstly, the steering torque curves must differ according to the different situations, and secondly, clearly noticeable changes within the different curves, in particular through partially significant gradient changes, must preferably be provided.

[0015] The drawing illustrates a preferred embodiment of the invention. Fig. 1. Different curves of the countersteering torque for two different situations and Fig. 2. A more detailed description of the two different situations.

[0016] In Fig. Figure 1 shows a characteristic map that can be stored, for example, in the form of a software table in an electronic control unit of a driver assistance system according to the invention. The characteristic map shows two curves K1 and K2, according to which (counter-)steering torques ML are specified depending on a parameter d or its danger value g.

[0017] The illustration shows only one explicit relationship between the hazard value g and the distance d as an example. However, the hazard value g can also be a measure calculated from several influencing factors, such as vehicle speed, approach speed to the barrier, and the current distance to the barrier.

[0018] A preliminary classification of the situation can be performed. This can take into account influencing factors such as "line is lane marking," "line is road edge," "vehicles in adjacent lanes," or even the driver's level of attention. Based on this classification, a decision is made as to whether characteristic curve K1 or K2 is used, with this characteristic curve then depending on the aforementioned geometric parameters.

[0019] As in Fig. As shown in more detail in Figure 2, let the parameter d be the distance of the vehicle F1, which is moving at a vehicle speed v1 in its own lane, to a lane marking FM that delimits its lane. The lane marking FM delimits according to Fig. 2 directly adjacent to the oncoming lane. Alternatively, the lateral distance from one's own vehicle to the overtaking or passing vehicle can also be used as an input parameter (in Fig. 2 not shown.)

[0020] The control unit uses sensors to query the distance d and situations S1 and S2, each with a different level of danger. The curve K1 is assigned to situation S1 with a low level of danger and could also be assigned to other situations with the same level of danger. The curve K2 is assigned to situation S2 with a high level of danger and could also be assigned to other situations with the same level of danger. Further curves, such as pronounced, impulsive curves, could also be provided for other levels of danger (not shown here).

[0021] The driver assistance system according to the invention can have only a single functional module or at least a first functional module (e.g., for lane keeping, "lane keeping assistant") and a second functional module (e.g., for preventing a collision during a lane change, "lane change assistant"). The first functional module can be assigned at least the first situation S1 and the second functional module at least the second situation S2.

[0022] The situation S1 is according to Fig. 2. In particular, the movement of the vehicle F1 away from the center of its lane towards the lane marking FM without the detection of any further potential hazard. A vehicle F2 approaching from behind at a higher speed v2 is not yet detected in situation S1.

[0023] The situation S2 is according to Fig. 2. The movement of the driver's own vehicle F1 away from the center of its lane towards the lane marking FM, with the recognition of a further potential hazard. In addition to the lane marking FM, which is directly adjacent to the oncoming lane, a further potential hazard is an overtaking maneuver by another vehicle F2 approaching from behind.

[0024] According to the embodiment according to the invention, in the case of situation S1 with a low degree of danger, the counter-steering moment ML increases with a generally increasing hazard value g of the parameter d, with a flat gradient at low hazard values ​​g.

[0025] In the case of situation S1 with a low degree of danger, the counter-steering torque ML increases with a steep gradient as the danger value g of the parameter d increases with increasing danger values ​​g.

[0026] In the case of situation S2 with a high degree of danger, the counter-steering torque ML increases with a steep gradient with increasing danger value g of the parameter d, as the danger value g increases.

[0027] In the case of situation S2 with a high degree of danger, the counter-steering moment ML increases with a flat gradient with increasing danger value g of the parameter d, as the imposition of a counter-steering moment ML generally increases with increasing danger value g.

[0028] With regard to the parameter d, the hazard value g of the parameter represents the current proximity of vehicle F1 to the lane marking FM. In other words, an increasing hazard value g here means a decreasing distance d, or increasing proximity to the lane marking FM. With regard to a parameter in the form of an approach speed, the increasing hazard value g would, for example, correspond to the increasing approach speed.

[0029] According to the embodiment example as described below Fig. 1 and Fig. 2. Thus, within the specific characteristic profiles K1 and K2, at least a portion of each profile is provided with a gradient steeper than the rest of the profile: for K1, a portion with higher hazard values ​​g, and for K2, a portion with lower hazard values ​​g. For situations with two hazard levels, i.e., S1 for a low hazard level and S2 for a high hazard level, a specific characteristic profile is defined for each hazard level, here K1 for the low hazard level and K2 for the high hazard level, whereby the profiles are essentially opposite in direction, here, for example, point-mirrored across axis A ( Fig.1) behavior; that is, for small hazard values ​​g, K1 exhibits a shallow gradient, and for large hazard values, K1 exhibits a steep gradient; in contrast, K2 exhibits a steep gradient for small hazard values ​​g and a shallow gradient for large hazard values ​​g. The steep gradients are determined – for example, empirically – in such a way that they are clearly noticeable in contrast to the shallow gradients.

[0030] In summary, the invention is based on the following insight: According to the prior art, the driver cannot be informed of the different levels of danger in a given situation due to the identical steering torque curves. Furthermore, a uniform increase in steering torque is less noticeable to the driver than a gradient-dependent increase. The driver perceives a significant change in the applied steering torque more readily. Both of these disadvantages can be overcome by varying the parameter dependency according to the invention, corresponding to situations with different levels of danger. In situations of low (or lower) risk level: At the beginning of the steering torque application, only a weak steering torque is built up, so that the vehicle is unconsciously guided away from the lane markings and back towards the center of the road. The vehicle is already beginning to react. If the driver still gets closer to the lane marking, the steering torque is increased with a steep gradient (relative to the respective parameter, for example the distance to the lane marking).

[0031] In situations of higher danger: The steering torque application here is exactly the opposite: first, a steep gradient is built up to draw the driver's attention to the more critical situation, then the increase is only made with a small gradient, as a stronger intervention by the driver can then be assumed.

[0032] The partially steeper gradient in each steering torque curve allows the driver to receive more noticeable feedback at certain times and as needed. The different steering torque curves, adapted to the levels of danger, allow the driver to perceive the danger of the situation more clearly. The required gradient steepness for noticeable feedback is preferably determined empirically.

Claims

[1] Driver assistance system with at least one function module by which a counter-steering torque (ML) is applied to the steering wheel of a motor vehicle (F1) depending on defined parameters (d) and depending on defined situations (S1, S2) of different levels of danger, with at least one electronic control unit and with sensors by which the control unit queries the parameters (d) and the situations (S1, S2) of different levels of danger, wherein in the electronic control unit a certain characteristic curve (K1, K2) of the counter-steering torque is specified for each defined situation (S1, S2) or all situations (S1, S2) of the same level of danger depending on at least one parameter (d) to be taken into account for all situations (S1, S2), characterized by , that For situations (S1, S2) of two levels of danger, a specific characteristic course (K1, K2) is specified for each level of danger, whereby the courses (K1, K2) behave in essentially opposite directions. [2] Driver assistance system according to claim 1, characterized by , that within the certain characteristic profiles (K1, K2) at least one part of each profile is provided with a gradient steepness that is more noticeable compared to the rest of the profile. [3] Driver assistance system according to one of the preceding patent claims, characterized by , that at least one first functional module and, if necessary, a second functional module are provided, wherein the first functional module is assigned at least one first situation (S1) of lower hazard level and the second functional module is assigned at least one second situation (S2) of higher hazard level. [4] Driver assistance system according to one of the preceding patent claims, characterized by , that a situation (S1) of lower hazard level is the movement of the motor vehicle (F1) away from the center of the roadway towards a roadway marking (FM) that limits the roadway without recognition of any further hazard potential. [5] Driver assistance system according to one of the preceding patent claims, characterized by , that a situation (S2) of a higher degree of danger is the movement of the motor vehicle (F1) away from the center of the roadway towards a roadway marking (FM) that limits the roadway with the recognition of a further hazard potential. [6] Driver assistance system according to the preceding patent claim, characterized by, that a further potential hazard is the movement of the motor vehicle (F1) away from the center of the roadway towards the road marking (FM) immediately adjacent to the opposite lane or the edge of the roadway and / or an overtaking maneuver by another vehicle approaching from behind (F2). [7] Driver assistance system according to one of the preceding patent claims, characterized by , that in situations of lower hazard level (S1) the countersteering moment (ML) increases with increasing hazard value (g) of the parameter (d) and with lower hazard values ​​(g) the countersteering moment increases with a flat gradient. [8] Driver assistance system according to one of the preceding patent claims, characterized by, that in situations of lower hazard level (S1) the countersteering moment (ML) increases with increasing hazard value (g) of the parameter (d) and with higher hazard values ​​(g) the countersteering moment increases with a steep gradient. [9] Driver assistance system according to one of the preceding patent claims, characterized by , that in situations of higher hazard level (S2) the countersteering moment (ML) increases with increasing hazard value (g) of the parameter (d) and with lower hazard values ​​(g) the countersteering moment increases with a steep gradient. [10] Driver assistance system according to any of the preceding claims, characterized by, that in situations of higher hazard level (S2) the countersteering moment (ML) increases with a generally increasing hazard value (g) of the parameter (d) with increasing hazard value (g) the countersteering moment increases with a flat gradient at higher hazard values ​​(g).

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