Driver assistance system for a motor vehicle

Abstract

The present invention relates to a driver assistance system for a motor vehicle, the driver assistance system having a positioning system (10) for positioning a vehicle traveling ahead and a longitudinal guidance module (12) for controlling the longitudinal movement of the vehicle according to positioning data of a target object, wherein the longitudinal guidance module (12) has a driving channel module (16) for defining a driving channel in front of the vehicle and a spacing adjustment function (20) for adjusting the time gap between the vehicle and the target object positioned in the driving channel to an appropriate value, characterized in that the longitudinal guidance module (12) has a dynamic function (22) that adjusts the longitudinal guidance function in the sense of rapidly starting acceleration according to a driver instruction under specific conditions indicating that the target object in the driving channel is about to leave.

Description

Technical Field

[0001] This invention relates to a driver assistance system for a motor vehicle, the driver assistance system having a positioning system for positioning a vehicle traveling ahead and a longitudinal guidance module for controlling the longitudinal movement of the vehicle based on positioning data of a target object, wherein the longitudinal guidance module has a driving channel module for defining a driving channel in front of the vehicle and a spacing adjustment function, the spacing adjustment function adjusting the time gap between the vehicle and the target object positioned in the driving channel to an appropriate value. Background Technology

[0002] The positioning system can consist of one or more angle-resolved radar sensors or a video system, and in addition to identifying distance and relative speed, it is also responsible for identifying the lateral movement of the object being located. Specifically, it can identify whether the object is inside or outside the driving lane. The distance adjustment function only reacts to objects within the driving lane and selects the object with the smallest distance as the target object, adjusting the distance relative to that target object. Generally, it does not directly adjust the spatial distance between these vehicles; more precisely, it adjusts time slots, i.e., time intervals, thereby automatically adapting the spatial distance to the corresponding driving speed.

[0003] The width of the driving lane is equal to the width of the vehicle plus a certain safety margin, so that objects located outside the driving lane can be safely passed under any circumstances.

[0004] In free-roaming conditions, meaning if no target is located, the vehicle's speed is adjusted to a desired speed selectable by the driver. If the vehicle approaches a vehicle traveling slowly ahead in the lane, the distance adjustment function is activated and the system enters a following mode, in which it tracks the vehicle ahead with an appropriate safe distance. Typically, the driver can select a time slot that limits the safe distance within certain limits.

[0005] If the driving lane is specified to be relatively narrow, there is a risk that the target object may be temporarily lost at a turn or when a vehicle ahead accidentally deviates from its path. This results in an uneven and uncomfortable driving experience with alternating accelerations and decelerations. Therefore, to ensure sufficient target object stability, the width of the driving lane is generally chosen to be relatively large.

[0006] However, if a slower vehicle ahead exits into another lane while following another vehicle, choosing a wider lane, the following vehicle initially decelerates before accelerating. This is because the spacing adjustment function only releases the target vehicle once it has left the relatively wider lane. In certain situations, such as when a vehicle ahead exits into a slower adjacent lane through the gap between heavy vehicles, this can cause obstruction. The overtaking process takes so long that the driver of the overtaken vehicle must slow down to avoid getting too close to the nearest heavy vehicle. Therefore, this can obstruct traffic flow in high-traffic conditions.

[0007] In principle, with driver assistance systems in place, the driver always has the potential to adjust the overdrive distance by actively manipulating the accelerator pedal. Therefore, while a higher acceleration can be achieved briefly, this higher acceleration only lasts for the same duration as the driver's accelerator pedal input. Consequently, the comfort improvements that should be achieved by driver assistance systems are limited. Summary of the Invention

[0008] The objective of this invention is to provide a driver assistance system that enables smoother traffic flow while maintaining high comfort and safety.

[0009] This task is solved according to the present invention by the following means: the longitudinal guidance module has a dynamic function that adjusts the longitudinal guidance function according to the driver's instruction to accelerate more rapidly under specific conditions indicating that the target object is about to leave the driving channel.

[0010] If the driver recognizes that a vehicle ahead is exiting but has not yet left the driving lane, the driver can activate the dynamic function by a brief instruction (e.g., by slightly manipulating and holding the accelerator pedal, or in the case of a single-wheeled vehicle, by slightly manipulating and holding the driving rotary handle) to enable the vehicle to begin accelerating to the desired speed before the target has left the driving lane.

[0011] Within the scope of this application and the described invention, reference is made specifically to driver command input for requesting acceleration or input devices for inputting driver commands. In the case of two-wheeled vehicles, such a device may be an accelerator pedal operated by the driver's foot. Alternatively, modifications of the input device that perform the same function as the accelerator pedal are also feasible. This includes, for example, devices for manual throttle operation, such as those offered as optional accessories by most vehicle manufacturers, or throttle levers or speed control handles, such as those used in single-wheeled vehicles like mopeds and motorcycles, or in motorized trikes or four-wheeled vehicles.

[0012] Such alternatives are obvious and those skilled in the art can readily conceive of these alternative devices available on the market without inventive effort.

[0013] Furthermore, within the scope of this application, only the concept of an accelerator pedal is used for reasons of greater understanding and readability; however, this concept also includes all other alternatives that are readily conceived by those skilled in the art, such as a throttle hand lever, a manual rotary lever, or a speed rotary lever.

[0014] This method can shorten the overtaking process, and the driver does not have to keep the accelerator pedal pressed or the rotary handle turned for the entire time.

[0015] Advantageous configurations and extensions of the present invention are derived from preferred embodiments.

[0016] A faster initiation of acceleration can be achieved in different ways: for example, by temporarily narrowing the lane, especially on the side where the preceding vehicle has exited, or by temporarily reducing the required time gap. In the first case, acceleration begins earlier. In the latter case, the vehicle accelerates to shorten the distance accordingly with the reduced time gap. However, the preceding vehicle typically leaves the lane before the shorter required distance is reached, causing the acceleration to stop only after the desired speed is reached.

[0017] The positive effect of reducing the time gap can also be that, in response to a larger acceleration, the vehicle's transmission management automatically switches to a lower gear. In this way, the vehicle's drive system prepares for a more dynamic acceleration process earlier, allowing it to accelerate to the desired speed more quickly while driving freely.

[0018] Driver commands to trigger dynamic functions can be input via the vehicle's accelerator pedal or rotary handle, or alternatively via other means, such as by manipulating the accelerator button. However, inputting via the accelerator pedal or, in the case of a single-track vehicle, via the rotary handle, has the advantage that the degree of pedal manipulation also determines the threshold or intensity for initiating the dynamic function. For example, more forceful manipulation of the accelerator pedal or rotary handle can further narrow the driving lane or more drastically reduce the time slot. Attached Figure Description

[0019] The embodiments are described in detail below with reference to the accompanying drawings. The drawings show:

[0020] Figure 1 Block diagram of the driver assistance system of the present invention;

[0021] Figure 2 The traffic situation has four stages, in which initially the vehicle being followed moves out of the adjacent lane while following another vehicle.

[0022] Figure 3 This illustrates the use of a driver assistance system according to the invention, and in... Figure 2 Passing through areas with similar traffic conditions;

[0023] Figure 4 The distance / time curve is used to illustrate the relationship between distance and time. Figure 3 A diagram illustrating the movement process;

[0024] Figure 5 A graph illustrating the time-varying curves of different parameters and parameters in the driver assistance system of the present invention; and

[0025] Figure 6 A flowchart illustrating the possible operating modes of the driver assistance system of the present invention. Detailed Implementation

[0026] exist Figure 1 The driver assistance system shown includes a positioning system 10, such as an angle-resolving radar sensor, and a longitudinal guidance module 12 that controls the longitudinal guidance of the vehicle based on positioning data obtained from the positioning system 10 by outputting commands to a drive system (not shown) of the vehicle via an output terminal 14.

[0027] The longitudinal guidance module 12 includes a driving lane module 16, which defines a driving lane 18 in front of the vehicle based on data obtained from the positioning system 10 and / or dynamic data characterizing the vehicle's motion state. Figure 2 This refers to a strip-shaped area extending substantially along the direction of travel on the road, the area being at least the width of the vehicle and the area within which the vehicle is expected to move during further travel. Specifically, the travel lane module 16 defines the left and right boundaries of the travel lane 18.

[0028] Furthermore, the longitudinal guidance module 12 has a spacing adjustment function 20, which is also symbolically shown in a box here, and is always activated whenever at least one preceding vehicle is positioned within the travel lane 18. For this purpose, the spacing adjustment function compares positioning data, particularly the lateral position of the positioned non-fixed object, with the travel lane boundary provided by the travel lane module 16. Objects within the travel lane to which the minimum spacing is measured constitute the target objects for spacing adjustment. Based on the spacing and relative speed with the target object, a positive or negative required acceleration is calculated and then output via output 14 such that the vehicle tracks the target object in a time slot selectable by the driver.

[0029] Furthermore, the longitudinal guidance module 12 includes a dynamic module 22, which obtains the target object's positioning data and the driving lane data through the spacing adjustment function and / or the driving lane module 18. The dynamic module 22 is connected to an input device 24, which in the illustrated example is the vehicle's accelerator pedal or rotary handle, through which the driver can actively input commands. If the target object's positioning data indicates that the target object is about to leave the driving lane, and if the dynamic module simultaneously receives a driver command, then the dynamic module 22 influences the spacing adjustment function 20 such that the vehicle's acceleration, which typically occurs only when the target object has actually left the driving lane, begins earlier and / or becomes more pronounced.

[0030] according to Figure 2 and 3 Explain the purpose of dynamic module 24.

[0031] exist Figure 2 The diagram illustrates four stages of traffic conditions A, B, C, and D, in which vehicle 26 changes from the middle lane 28 to the adjacent lane 30 on the right. The future route of vehicle 26 is indicated by a dashed arrow. The following vehicle 32 is equipped with a driver assistance system and will be referred to below as "this vehicle". Figure 2 It is assumed that this driver assistance system is a conventional system without a dynamic module 22. The speed v of the vehicle 32 is indicated by the vector arrow.

[0032] In phase A, the speed v of vehicle 32 is greater than the speed of the preceding vehicle 26, causing a decrease in the distance between these vehicles. Positioning system 10 has sensed the preceding vehicle 26 and identified it as being within the travel lane 18. The distance adjustment function 20 commands a negative acceleration of vehicle 32, causing the vehicle's speed to decrease and preventing it from approaching the preceding vehicle 26 too closely.

[0033] In phase B, the speed v of this vehicle decreases to the speed of the vehicle ahead, so that the spacing and time gap between the two vehicles remain constant. The vehicle ahead has moved slightly to the right and has just crossed the boundary between lanes 28 and 30. However, the vehicle ahead remains within the driving lane 18, so that spacing adjustment continues.

[0034] In phase C, the preceding vehicle 26 has completely left the middle lane 28, allowing the vehicle 32 to accelerate again. However, the preceding vehicle 26 has not yet completely left the driving lane 18, so the preceding vehicle has not been removed as a target, and the spacing adjustment continues, allowing the vehicle to continue traveling at the slower speed of the preceding vehicle 26 and tracking it with a constant time slot.

[0035] The preceding vehicle 26 leaves the driving lane 18 in stage four D, and the vehicle 32 accelerates again, thus initiating the overtaking process.

[0036] Figure 3 Shown with Figure 2 The same traffic incident occurred, but this time it is assumed that the vehicle is equipped with the driver assistance system of the present invention, which has a dynamic module 22. The situation in phase A is similar to... Figure 2 The same situation applies in phase B. In phase B, the positioning system has detected that the lateral position of the preceding vehicle 26 has changed. The driver of vehicle 32 also detects that the preceding vehicle 26 is moving out into the adjacent lane 30, and therefore manipulates input device 24 to trigger the dynamic function. The dynamic function thus causes the driving lane 18 to narrow by moving the right boundary of the driving lane to the left. However, the preceding vehicle 26 has not yet left the narrowed driving lane, so the spacing adjustment continues in phase B.

[0037] In phase C, the preceding vehicle 26 has not only completely left the middle lane 28 but also the driving lane 18, causing the spacing adjustment function to deselect vehicle 26 as the target and allowing vehicle 32 to accelerate in this phase. Therefore, the overtaking process begins earlier and ends correspondingly earlier, allowing vehicle 26 to re-enter the middle merging lane 28 earlier if there are slower vehicles further ahead.

[0038] exist Figure 4 The distance / time curve is shown in the form of a graph. Figure 3 The movement is shown in the diagram. Time t is plotted on the vertical axis and position x along the longitudinal direction of the road is plotted on the horizontal axis. The dashed curve 26a indicates the position of the preceding vehicle 26 as a function of time t. The solid curve 32a indicates the position of vehicle 32 according to... Figure 3The position of the vehicle 32 during its movement. For comparison, curve 32b shows the position of the vehicle 32 according to... Figure 2 The position through which the movement passes. And Figure 2 and 3 The corresponding time points from stage A to stage D are marked with horizontal lines.

[0039] Caused by dynamic module 22, vehicle 32 has accelerated again in phase C, as indicated by curve 32a. At time point E, vehicle 26 is overtaken (curve 32a intersects curve 26a). Without the dynamic module, at this time point, the acceleration of vehicle 32 has just begun (phase D) and vehicle 26 would not be overtaken until a significantly later time point E'.

[0040] Figure 5 An example is shown where dynamic module 22 not only causes a reduction in the travel path but also a reduction in the required time slot for tracking the target object. Figure 5 Curve 34 in the upper graph indicates the change of the logical variable FS as a function of time t. If the variable has a value of 0, the driving lane 18 has a normal width. If the variable has a value of 1, the width of the driving lane is reduced by a certain amount. This amount can be fixed or variable and is chosen in any case such that the width of the driving lane is greater than the width of the vehicle.

[0041] exist Figure 5 Curve 36 in the second graph indicates the value of the logical variable TS as a function of time t. This variable indicates the appropriate time slot reduction to track vehicle 26. TS = 1 means that the spacing adjustment is performed at a regular time slot selected by the driver. TS = 0 means that the time slot is reduced by a specific amount, causing vehicle 32 to temporarily accelerate. In the example shown, the lane reduction begins in phase B, and the time slot should also decrease later.

[0042] exist Figure 5 Curve 38 in the third graph indicates the state of the logical variable ZO as a function of time t. The variable ZO indicates whether the target object is sensed (ZO = 1) or released (ZO = 0). In the example shown, the target object is released at time point D.

[0043] exist Figure 5 Curve 40 in the fourth graph indicates the value of the logic variable G as a function of time t. Variable G marks a gear shift: during which the vehicle's transmission shifts down one gear to allow for smoother acceleration. This gear shift is automatically triggered by the vehicle's transmission management unit based on the acceleration request output via output terminal 14.

[0044] exist Figure 5 Curve 42 in the figure indicates the rotational speed N of the drive motor as a function of time t, and curve 44 indicates the acceleration a of the vehicle as a function of time t.

[0045] In the example shown, the timing of the slot reduction, represented by the variable TS, is chosen such that the temporary acceleration phase triggered by the slot reduction has not yet ended at time point D—the time at which the target object is released. This prevents the vehicle from decelerating again, ensuring the proper reduction in spacing is maintained before acceleration resumes at time point D. As indicated by curve 40, in this example, the gear shift and slot reduction (curve 36) occur simultaneously. Here, the engine speed N jumps up in response to the smaller gear, and then further increases in response to vehicle acceleration (Drehzahlaufbau). Due to the gear shift and corresponding increase in engine speed at time point S, the driver receives feedback that the dynamic function has been triggered according to his command. Figure 6 The flowchart illustrates an example of a particular configuration of the dynamic function. As long as the spacing adjustment function 20 is active, the algorithm represented by this flowchart is repeated periodically in the longitudinal guidance module 12.

[0046] In step St1, it is checked whether the spacing adjustment function is active. If not (N), the entire algorithm for the dynamic function is skipped. Otherwise (Y), in step St2, data from the positioning system 10 is queried. Then, in step St3, the accelerator pedal threshold or rotary handle threshold is calculated based on this data. In this embodiment, the vehicle's accelerator pedal or rotary handle constitutes input device 24. If the driver manipulates the accelerator pedal or rotary handle and the accelerator pedal or rotary handle exceeds the threshold calculated in step St3, this is interpreted as an instruction to trigger the dynamic function. For example, the more strongly the lateral position (perpendicular to the direction of travel) of the preceding vehicle 26 deviates from the middle of lane 28 or the middle of the driving lane 18, and the faster the lateral movement of the preceding vehicle, the more strongly the accelerator pedal threshold or rotary handle threshold drops.

[0047] Then, in step St4, a series of criteria are checked, all of which must be met to trigger the dynamic function. The first criterion is that the vehicle's speed v must be higher than a defined threshold S1. At low speeds, such as in urban traffic, this dynamic function is meaningless. More specifically, this function is primarily considered for highway traffic.

[0048] Another criterion is that the absolute value of the lateral offset of vehicle 26, |d|, must be higher than a defined threshold S2. This criterion is an indication that vehicle 26 is leaving the driving lane. Here, the lateral offset d is defined as the lateral deviation of vehicle 26 relative to the center of the driving lane 18.

[0049] Another criterion is that the curvature k of the driving lane is below a predetermined threshold S3. The curvature of the driving lane is determined by the vehicle's projected route and is generally calculated based on the vehicle's dynamic data, and, where necessary, also based on location data indicating road direction, such as guardrails, guardrail posts, or (if a video system is present) road markings. Limiting the curvature of the driving lane prevents the dynamic function from being erroneously triggered due to lateral deviations being misinterpreted as lane change signals in cases where the road is very winding.

[0050] Another standard stipulates that the brake pedal is not operated by the driver of the vehicle and the driver is not about to initiate a lane change from his / her direction. Therefore, it is required that the hazard lights are not turned on and any overtaking assist functions are not activated.

[0051] Furthermore, the decisive criterion is that the degree of manipulation of the accelerator pedal or rotary handle FP is higher than the threshold S4 calculated in step St3.

[0052] Finally, the following condition must be met: there must actually be a situation where the vehicle is following another vehicle, that is, the appropriate time slot T selected by the driver must be met. soll Not less than the current time slot Td (the current distance between vehicles 26 divided by the speed v).

[0053] If all these conditions (Y) are met, then the driving lane is reduced in step St7. Otherwise (N), the algorithm ends.

[0054] If the result in step St4 is positive, step St5 checks whether all the criteria for reducing the time slot are met. One of these criteria is that the magnitude of the lateral offset of vehicle 26, |d|, is not only higher than threshold S2, but also higher than the higher threshold S5. This criterion is a stronger indication that vehicle 26 is about to leave its lane.

[0055] Another criterion is that the degree of manipulation of the accelerator pedal or rotary handle FP is higher than the higher threshold S6. That is, the time slot is reduced only when the driver strongly requests the dynamic function and presses the accelerator pedal more forcefully or twists the rotary handle more.

[0056] Finally, the following criterion is also tested: the current time slot Td does not exceed a defined threshold S7. This prevents premature time slot reduction and related vehicle acceleration.

[0057] If all these criteria (Y) are met, the width of the time slot is reduced in step St6. Otherwise (N), step St6 is skipped, and the travel lane is reduced directly in step St7. However, in step St7, only it is decided that the width of the travel lane should be reduced, but it is not yet determined whether this is achieved by moving the left or right boundary of the travel lane. To make this decision, in step St8, it is checked whether the lateral offset d is positive or negative. If the lateral offset is negative (d<0), this means that vehicle 26 moves to the right and in step St9, the right boundary of travel lane 18 is moved (to the left). If the lateral offset is positive, the left boundary of the travel lane is moved (to the right) in step St10.

[0058] The algorithm ends at step St9 or step St10, and then jumps back to step St1.

[0059] The thresholds S1 to S7 used for testing in steps St4 and St5 may be constant or may vary depending on the implementation method.

Claims

1. A driver assistance system for a motor vehicle, having a positioning system (10) for positioning a preceding vehicle (26) and a longitudinal guidance module (12) for controlling the longitudinal movement of the own vehicle (32) in dependence on the positioning data of the positioned object, wherein The longitudinal guidance module (12) has a travel channel module (16) for defining a travel channel (18) in front of the own vehicle and a distance regulation function (20) which regulates a time slot between the own vehicle (32) and a target object positioned in the travel channel (18) to a desired value, characterized in that the longitudinal guidance module (12) has a dynamic function which, under specific conditions indicating that a target object in the travel channel (18) is about to leave, adjusts the longitudinal guidance function in the sense of a more rapid start of acceleration in accordance with a driver's instruction, wherein the dynamic function adjusts the longitudinal guidance function by reducing the width of the travel channel (18), wherein the dynamic function is triggered only if all of the following criteria are met: the speed of the own vehicle (32) is higher than a first threshold value; the absolute amount of lateral offset of the preceding travel vehicle (26) is higher than a second threshold value, wherein the lateral offset is defined as the lateral deviation of the preceding travel vehicle (26) relative to the center of the travel channel (18); the curvature of the travel channel (18) is lower than a third threshold value; the degree of a steering acceleration pedal or a rotary handle of the own vehicle (32) is higher than a fourth threshold value; the brake pedal of the own vehicle (32) is not actuated by the driver of the own vehicle (32) and the driver of the own vehicle (32) is also not about to initiate a lane change from his side; the desired value of the time slot is not smaller than the current time slot between the own vehicle (32) and a target object positioned in the travel channel (18).

2. Driver assistance system according to claim 1, in which the dynamic function adjusts the longitudinal guidance function by reducing the desired value of the time slot.

3. Driver assistance system according to any of the preceding claims, in which the input means (24) for inputting a driver's instruction are means for sensing the position of an acceleration pedal of the vehicle or are means for sensing the position of a handle of the vehicle and for comparing the position with a threshold value.

4. Driver assistance system according to claim 3, in which the dynamic function changes the threshold value for the position of the acceleration pedal or the threshold value for the position of the handle depending on the situation.

5. Driver assistance system according to claim 3, in which different threshold values are applied for the position of the acceleration pedal or the position of the handle in order to reduce the width of the travel channel and in order to reduce the time slot.

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