KR102562411B1 - Method for assisting a driver of an ego-vehicle when driving through a curve lying ahead - Google Patents

Abstract

The present invention (100) relates to a method (100) for assisting a driver of a vehicle for his vehicle when passing a curve ahead, the method comprising: calculating a curve profile of the curve ahead and a curve entry point; Calculation step 101, wherein determination of the curve entry point is performed according to the calculated curve profile and the current natural speed and/or current acceleration of the own vehicle; calculating (102) a maximum permissible speed limit profile along the curve profile; Comparing (103) the maximum permissible limit speed profile along the curve profile with the expected current specific speed, when the expected current specific speed exceeds a predetermined speed threshold, the vehicle is calculated from the determined curve entry point. and a comparison step (103) of performing (104) the control independently of the driver at the selected reference specific speed.

Description

A method for assisting the driver of the own vehicle when passing a curve located in front

The present invention relates to a method and apparatus for assisting a vehicle driver of a host vehicle when passing a curve located ahead.

Modern automobiles are equipped with various driving dynamics control systems such as ESC (Electronic Stability Control), and these systems can affect the driving behavior of the vehicle depending on the purpose. In order to maintain driving stability, ie to ensure that the vehicle follows the driver's instructions, wheel-specific braking forces can be generated and/or the driving moment reduced automatically. These control interventions are derived directly from the driver's inputs (steering, braking, acceleration) and are performed in a responsive manner, so that the interventions of the driving dynamics control are measures of the driver's needs whose driving behavior is calculated with reference to the vehicle model. It is only done when it differs from the possible value. An active driving dynamics control system is known, for example, from EP 0 792 229 B1.

Currently, approaches are being taken to provide early warning to drivers of potentially dangerous curb situations. With reference to the digital map, information about the curve located ahead is calculated, eg geometrical characteristics. At this time, with reference to satellite navigation (GPS: Global Positioning System), the unique position (self-position) of the vehicle is determined by an electronic control device (IPC: Inertial and Position Cluster) either alone or in conjunction with an inertial sensor device or inertial navigation . Such a CSW system warns the driver if the driver is approaching a curve too quickly.

In particular, when the vehicle speed significantly exceeds the speed limit, the driver's response may be carried out too slowly and/or too delayed. Against this background, driver assistance or stability functions such as, for example, PreviewESC (ESC = Body Stability Control) are known, which perform braking interventions independently of the driver and/or reduce the drive moment to reduce driving speed. Decrease. From DE 10 2012 212616 A1, for example, a method for improving the driving stability of a vehicle is known, in which a braking intervention independent of the driver is made when the vehicle's section information and temporary position data can predict a critical driving situation. this is triggered A braking intervention is carried out at two or more wheels of the vehicle and/or the driving moment is reduced in such a way that the temporary driving speed approaches the limit speed. According to one embodiment, the applied braking force is selected according to the difference between the instantaneous travel speed and the limit speed and/or according to the distance to the segment including the minimum radius of curvature. This enables rapid driving and avoids inappropriately strong braking interventions.

Systems that are speed-adjusted to the absolute radius of curvature have the disadvantage of providing static and inflexible control over the passage of a curve, which can lead to premature or too late intervention. In particular, when braking intervention is delayed, the presence of lateral dynamics may limit the reduceable longitudinal forces too strongly, thus causing instability of the vehicle. In addition, the inflexible control imparts a random vehicle driving feel to the driver. On the other hand, the driver requires safety-oriented and understandably smooth driving of the vehicle.

The task underlying the present invention is therefore to propose a method and a device for conveying an improved driving feel for the vehicle driver when assisting the passage of a curve located ahead.

This problem is solved according to the invention by a method according to claim 1 , a computer program product according to claim 8 , a device according to claim 9 and a vehicle comprising the features of claim 10 . Preferred or advantageous embodiments of the invention are presented in the dependent claims, the following detailed description and the drawings.

A method for assisting a vehicle driver of a subject vehicle when passing a curve located ahead is proposed. The method includes the following steps: Calculating the curve profile, in other words, the curvature profile, and the curve entry point of the curve located in front. The determination of the curve entry point is made according to at least the calculated curve profile as well as the current natural speed and/or current acceleration of the own vehicle. In this regard, the concept of acceleration includes the sound acceleration of the subject vehicle. The current natural speed or the current acceleration refers in particular to at least one detected value at a specific time range or a definite time point in which an entry of the own vehicle into a curve ahead is imminent, for example. In particular, the time range or time point may be determined by a time interval or path distance to a curve located in front, for example, a calculated curve apex of the curve.

In addition, the maximum permissible limit speed profile is calculated along the curve profile. In particular, the maximum permissible limit speed profile represents the maximum possible speed or speeds of the subject vehicle along a curve profile, and if this limit speed profile is exceeded, the subject vehicle may depart due to oversteer or understeer.

In particular, the maximum allowable limit speed profile along the curve profile at least at the curve apex is compared with the expected current specific velocity. The expected current specific speed is calculated using, for example, an extrapolation method of the specific speed of the own vehicle detected at the time of imminent entry.

In addition, if the expected current specific speed exceeds at least or exactly one predetermined speed threshold, driver-independent control, in particular braking intervention, is performed from the determined curve entry point to the calculated reference specific speed of the subject vehicle. The reference specific speed represents one or more speed values, in particular, which are established along the curve profile, with the help of which speed values it is possible to safely pass the curve, which lies below the maximum permissible limit speed profile and thus obtains maneuverability and lane stability. this is guaranteed At least or exactly one predetermined speed threshold value may, for example, represent the minimum value of the maximum permissible speed profile to be calculated. The reference specific speed is calculated using, for example, a curve profile and a vehicle model.

By determining the curve entry point according to the calculated curve profile and the current natural speed or acceleration, a static, i.e. fixedly determined curve entry point is not provided, but together with the vehicle dynamics of the dominant own vehicle before entering the curve. It is decided. In this way, when the vehicle is traveling slowly, the curve entry point moves towards the rear of the route section, whereas when the vehicle is traveling relatively quickly, the curve entry point moves towards the front on the same curve. Thus, the essential advantage is obtained that a uniform, yet comfortable, dynamic and acceptable vehicle control is performed for the vehicle occupants. At the same time, the curve entry point is determined by the relationship between the natural speed and the curve profile, which enables a braking intervention tailored to the current traffic situation, often resulting in improved driving stability compared to emergency braking at increased speeds. cause

According to a preferred embodiment, in order to determine the curve entry point, the reference specific speed of the own vehicle for the time range passing through the curve profile is calculated. In particular, the reference specific velocity is determined using an empirically calculated factor, which is multiplied by the expected current specific velocity along the curve profile. Preferably, the limit speed profile is calculated with reference to the calculated curve profile of the curve located ahead. It is also contemplated, in particular, to evaluate low points in the limiting speed profile as critical curve points. A critical curve point may represent, for example, the peak and/or highest curvature of the curve. In particular, the path point of the limit velocity profile that first falls short of the reference specific velocity between the curve beginning and the critical curve point is determined as the curve entry point. Thus, the curve entry point is established efficiently and reliably.

According to another preferred embodiment, the maximum possible delay to the detected critical curve point is calculated, and the curve entry point is determined as a route point substantially corresponding to the path segment of the calculated maximum possible delay to the detected critical curve point. In the context of the present invention, the expression "substantially" means deviations of +/-10%, preferably +/-5%, and/or functionally insignificant change states, respectively, from the exact value. Optionally and complementarily, the route section of the maximum possible delay for determining the curve entry point is supplemented with section parts that provide additional rigidity, for example to ensure a comfortable control behavior for the driver even when deviations or inaccuracies are not predicted. It can be. This embodiment is likewise a good way to determine the curve entry point to suit current traffic and vehicle dynamic conditions as much as possible.

Preferably, the limit speed profile for passing the curve is calculated based on the predetermined lateral acceleration of the curve located ahead and the calculated curve profile. For example, the predetermined lateral acceleration is calculated using a mathematical model.

In order to calculate the desired lateral acceleration, in particular, a friction value is determined between the tires of the subject vehicle on the way to travel. For example, the determination of the friction value is carried out using a friction value estimating device in the vehicle, i.e., an on-board estimating device, or alternatively or alternatively or supplementarily via a Car-to-X communication device, in particular, for example, a friction value card. It is performed through the cloud that provides

As an alternative, the friction value is set with a one-time definitive value that ensures safe passage of the curve even in adverse weather conditions. Preferred embodiments allow for the friction value to be determined by input from the vehicle driver of the subject vehicle, for example through a human-machine interface known as an HMI. More preferably, the friction value is determined by a driving mode selection performed by a vehicle driver. Depending on the driving mode, different lateral accelerations are caused and, accordingly, different friction values are caused. Therefore, for example, when the comfort mode is selected, a lower lateral acceleration is required than when the sport mode is selected. It is also conceivable that the evaluation device of the own vehicle evaluates specific road-surface or weather conditions and assigns corresponding friction values to these conditions. Evaluating conditions of the current driving route, e.g., using camera images from an in-vehicle camera facility, using wiper operation, or other direct or indirect inputs by the driver of the vehicle, and determining a friction value in relation thereto device is formed. In this way, the lateral acceleration determined can be adjusted to the current travel path conditions.

According to a preferred embodiment, the curve profile of the curve located ahead is calculated using digital map data and/or camera data of the vehicle's in-vehicle camera facility.

Another subject of the present invention relates to a computer program product for driving a vehicle, and the computer program product includes instructions for performing the method according to the above description when executed in a controller or a computer of the vehicle.

Another subject of the invention relates to a device for assisting a driver of a vehicle for its own vehicle when passing a curve ahead, in particular a driver assistance or stability device, which device comprises the curve profile of the curve ahead and the curve A processing facility for calculating an entry point, the processing facility being configured to calculate a curve entry point according to the calculated curve profile and the current natural speed and/or current acceleration of the vehicle, the processing facility according to the curve profile. It is configured to calculate the maximum allowable limit speed profile, and the processing facility is configured to compare the expected current specific speed with the maximum allowable limit speed along the curve profile. The device includes a control facility, wherein the control facility is configured to perform driver-independent control from the calculated curve entry point to the reference specific speed of the subject vehicle when the expected current specific speed exceeds a predetermined speed threshold. is formed The device is thus designed to assist the driver of the vehicle, preferably by means of a braking intervention, before the subject vehicle can approach a critical driving stability situation, in particular due to an increase in speed.

Another subject of the invention relates to a vehicle comprising the device as described above.

Hereinafter, the present invention is explained in more detail with reference to preferred embodiments. The drawing is as follows:
1 a simplified schematic diagram of the procedure scheme of the method according to the invention;
The upper graph of FIG. 2 is an exemplary curve profile, and the lower graph correspondingly shows a first embodiment of calculating a curve entry point;
3 - 5 The second embodiment in which the upper graph is an exemplary curve profile and the lower graph calculates the curve entry point correspondingly.

1 shows a simplified procedural diagram of a method 100 according to the invention for assisting a vehicle driver for his vehicle in passing a curve ahead, the method comprising: the curving path of the curve ahead and A step of calculating a curve entry point, wherein the curve entry point is determined according to the calculated curve path and the current natural speed and/or current acceleration of the subject vehicle (101). A maximum allowable speed limit profile along the curve profile is calculated (102). In the next step, the expected current specific velocity and the maximum allowable limit velocity profile along the curve profile are compared (103), and when the expected current specific velocity exceeds a predetermined velocity threshold, the calculated from the determined curve entrance point Control independent of the driver is performed at the reference specific speed of the subject vehicle (104).

A first embodiment for calculating the curve entry point is described using the simplified graph of FIG. 2 . A first graph in FIG. 2 shows an exemplary curve profile of a curve through which the own vehicle will pass. The critical point represents the highest curvature of the curve. In the second graph located below, the limit velocity profile along the curve profile and the expected current specific velocity are shown purely by way of example. The limit speed profile is calculated, for example, with reference to the calculated curve profile of the curve located ahead, and at this time, a low point in the limit speed profile is evaluated as a critical curve point. In order to determine the curve entry point, the reference specific speed of the own vehicle during the time range passing through the curve profile is calculated. The reference specific velocity is determined using an empirically calculated factor k, which is multiplied by the expected current specific velocity along the curve profile. By multiplying the expected current specific speed by the empirically calculated factor k, it is ensured that the subject vehicle is stable, in particular, at the intersection of the curve profiles. Between the beginning of the curve and the critical curve point, the path point of the limit speed profile that first falls short of the reference specific speed, that is, the path point indicated herein as the intersection of the linear profiles of the limit speed and the reference speed is determined as the curve entry point. The method according to the invention requires a uniform and controlled braking intervention strength in passing the curve.

A second embodiment for calculating the curve entry point is described using the simplified graphs of FIGS. 3 to 5 as well. As in FIG. 2 , an example curve profile is shown in the first graph. 3 to 5, the lower graphs show the limit velocity profile along the curve profile, the expected current specific velocity, and the specific velocity profile at the maximum possible automatic delay. Thus, the maximum possible delay to the detected critical curve point can be calculated using, for example, a mathematical model. In particular, the curve entry point is determined as a route point substantially corresponding to the route section of the maximum possible delay calculated up to the detected critical curve point. Optionally, supplementally, additional safety routes may be considered for these route segments when more appropriate control is required.

As transverse dynamics prevail, only certain delays can be reduced, as is shown in the different plotted high-velocity profiles, eg in FIGS.

The maximum reduceable automatic delay can be limited by two different factors. On the one hand, it is limited by the functional design, ie by a certain delay of less than 2.5 m/s ² eg as shown in FIGS. 3 and 4 . On the other hand, as shown in FIG. 5 , it is limited by physical limitations in driving dynamics. In the latter case, the smaller the difference between the expected current natural speed and the limit speed, the larger the traction circle representing the ideal relationship between the longitudinal force and the cornering force at the wheel of the vehicle is utilized, thus reducing the delay. may appear less.

Claims (10)

As a method of assisting the driver of a vehicle of its own vehicle when passing a curve located ahead:
- Calculating a curve profile and a curve entry point of the curve located ahead, wherein the determination of the curve entry point is performed according to the calculated curve profile and the current specific speed and/or current acceleration of the own vehicle. , calculation step 101;
- calculating (102) a maximum permissible limit speed profile along said curve profile;
- step 103 of comparing the maximum permissible limit speed profile along the curve profile with the expected current specific speed, when the expected current specific speed exceeds a predetermined speed threshold, the determined curve entry point a comparison step (103) in which driver-independent control is performed (104) at the calculated reference specific speed of the subject vehicle from (104);
The reference specific speed of the own vehicle is calculated for a time range passing through the curve profile, the limit speed profile is calculated with reference to the calculated curve profile of the curve located in front, and in the limit speed profile a low point is evaluated as a critical curve point, and a path point of the limit velocity profile that first falls short of the reference specific velocity between a curve start and going to the critical curve point is determined as a curve entry point. delete The method of claim 1 , wherein a maximum possible delay to a detected critical curve point is calculated, and the curve entry point is determined as a path point substantially corresponding to a path segment of the calculated maximum possible delay to the detected critical curve point. which way. The method according to claim 1, wherein the limit speed profile for passing the curve is calculated based on a predetermined lateral acceleration and the calculated curve profile of the curve located in front. The method of claim 4, wherein a friction value is determined to calculate the predetermined lateral acceleration, and the determination of the friction value is performed using a friction value estimation device or by a vehicle driver's input through a human-machine interface. which way. 6. The method of claim 5, wherein the friction value is determined by a driving mode selection performed by the vehicle driver. The method according to claim 1, wherein the curve profile of the forward-positioned curve is calculated using digital map data and/or camera data. A computer-readable storage medium storing a computer program for driving a vehicle, wherein the computer program, when executed in a controller or a computer of the vehicle, is the method according to any one of claims 1 and 3 to 7. A computer readable storage medium comprising instructions to perform As a device for supporting the vehicle driver for the subject vehicle when passing a curve located in front
A processing facility for calculating a curve profile and a curve entry point of the curve located ahead, configured to calculate the curve entry point according to the calculated curve profile and the current specific speed and/or current acceleration of the own vehicle. ;
formed to calculate a maximum permissible speed limit profile along the curve profile;
a processing facility configured to compare the maximum permissible limit speed along the curve profile with an expected current specific speed; and
When the expected current specific speed exceeds a predetermined speed threshold, a control facility formed to control the calculated curve entry point to the reference specific speed of the subject vehicle independently of the driver,
The reference specific speed of the own vehicle is calculated for a time range passing through the curve profile, the limit speed profile is calculated with reference to the calculated curve profile of the curve located in front, and in the limit speed profile The low point is evaluated as a critical curve point, and a path point of the limit velocity profile that first falls short of the reference specific velocity between a curve beginning and going to the critical curve point is determined as a curve entry point. A vehicle comprising a device according to claim 9.