DE102008040627A1 - Method for regulating or controlling steering assistance system for vehicle, involves calculating convergence at peripheral object, where convergence is adapted depending on engaging free area or steering engagement - Google Patents

Abstract

The method involves calculating a convergence at a peripheral object. The convergence is adapted depending on an engaging free area (16) or a steering engagement. The engagement free area is provided, such that a minimum distance is maintained from the peripheral object. An independent claim is included for a steering assistance system for a vehicle with a unit for providing an engaging free area.

Description

State of the art

The invention is based on a device or method for operating a steering assistance system with adaptation in environment object approximation according to the preamble of the independent claims. A steering assistance system, akin to a Lane Keeping Support System (LKS), is used in the DE 10137 292 A1 described. Here ambient data of a current traffic situation are detected and compared with the movement data of the vehicle to the effect that a meaningful trajectory of the vehicle (trajectory) is determined and beyond the steering handle (steering wheel) is acted upon by a corresponding actuator with a steering torque. Usually, the main focus is on the lane recognition, ie the lane-limiting elements are detected, for example video-based and calculated the optimal driving course in the middle between these limits.

adversely at steering assistance systems in general is that the driver uncomfortable driving feeling can be conveyed, if the Driver does not want to perform the light steering movement as the system wants. In addition to the aggravated steering movement, where a manual Force must be applied against the control torque, the feeling can come to the tutelage.

In Scripture DE 10 2005 049 071 A1 The Applicant addresses this problem by not only calculating a certain ideal line, such as the center of the lane mentioned above, but steering intervention is not already done with small deviations from the nominal line, but only when the deviation reaches a certain size. There is therefore a specific area around the middle of the lane (= desired trajectory) in which no steering intervention takes place (area without intervention). This ensures that the driver can independently select the driving position in his lane within this framework, without feeling a steering intervention. Depending on the size of the area, it may happen that the vehicle travels at the edge of the lane, which is not safety-critical in some situations, but in some situations too close approaches to objects on the edge or next to the lane, especially vehicles on adjacent lanes, eg. B. when overtaking, can come. Although a direct collision or a collision course is avoided by driver assistance systems, driving past surrounding objects, for example a right-hand drive truck, when overtaking may be perceived as unpleasant or in extreme cases lead to a frightening reaction of one of the drivers.

Disclosure of the invention

The Inventive device or method with the features of the independent claim has in contrast the advantage that the steering assistance system already then early engages when environment objects are detected, which are their own Approaching vehicle unnecessarily close. Becomes recognized at least one environment object and performs a rating of parameters, such as the trajectories of the vehicle and of the object to a critical representation, so for example a direct intervention of the LKS done, which is usual way but by well-known, integrated in LKS algorithms for environment detection is carried out. The LKS works with a described non-intrusive area, so may instead or additionally This area will be adapted so that a steering intervention already at lower (or possibly at longer) distance from the reference point of the non-engaging area (in the middle of the roadway center) takes place.

usual It is thereby achieved that the own vehicle has a lower, So-called cross-shelf can build up before the steering assistance system Correctly intervenes and the vehicle back to the center the lane would move. It avoids that Querablage becomes too large, if, for example, at the Neighbor track is a vehicle to which a too close approach was perceived as unpleasant.

Advantageous is to reduce the non-impact area so that a minimum distance is maintained by the environment object. This minimum distance can for example, by empirical experiments through subjective perception determined and configured in the system. Here you can fixed values are used, as well as environment parameter dependent Values where, for example, a greater distance at higher speeds and / or differential speeds is set.

Advantageously, alternatively, the engagement-free region can be reduced in such a way that the region around the full trajectory is reduced by or to a fixed amount or, alternatively, it is relatively reduced depending on environmental variables. On it, for example, parameters such as the lane width, the Geschwin and the distance to the environment object. The non-invasive area can also be adapted on one side, ie only on the side of the trajectory on which the environment object will be when driving past.

Advantageous is, if the adaptation takes place such that the torque characteristic of the LKS system. Thus, not a new rule algorithm activated or added additional conditions in the algorithm, but by adapting the parameter set, from the u. a. the torque characteristic As a result, the current regulatory procedure can simply be maintained become.

Favorable Way further characteristics of the environment object in particular, here are the size, the current position, the position calculated in advance Point of maximum approximation and potential hazard, that comes from the environment object, to name. This can be determined be limited to what extent the non-invasive area or should be extended so that the situation takes appropriate account will be carried.

Advantageous it is when the maximum approximation to the surrounding object, d. H. the minimum distance between the vehicle and the surrounding object and the time when this event occurs will be determined. There these parameters are predictions in the future and extrapolation, there is uncertainty if necessary, be taken into account by appropriate provisions / buffers got to. Furthermore, with knowledge of these sizes a meaningful point in time can be determined, on which the invention is soft Procedure must unfold its effect.

Advantageous is the formation of a decision to use of the method according to the invention based thereon, that the achievement of a critical cross-storage is determined in advance, d. H. when and where the vehicle so off the target trajectory (but still within the normal non-intrusive range) so it would be uncomfortable if at this point an environment object in the neighborhood, e.g. B. on the secondary track itself would be located (longitudinal distance). Considering The driving dynamics and trajectories become a so-called catch area determines in which an environment object in the coordinate of the direction of travel must be, so that the inventive method is activated. The corresponding calculations become permanent performed so that dynamic changes do not have too much impact on the prediction. usual In this way, only environment objects must be considered who are approaching the vehicle, or who the Vehicle approaches, otherwise the problem does not occur on. For example, the method can be used in the passing of slower traffic on the neighboring lane or even if a faster vehicle overtakes its own vehicle on a neighboring lane. In this case, appropriate sensor devices be present to the backward traffic to observe.

Possibly. already contains the vehicle trajectory calculated by the LCS system already environment data (possibly from other driver assistance systems) in such a way, that the application of the method according to the invention superfluous if the trajectory around the environment objects is sufficient big distance pulls. In this case, if necessary, a total system vote necessary.

Definitions

synonym Here are the terms steering assistance system, guidance systems, Lane Keeping Support System (LKS) or similar terms used. A guidance system according to the The state of the art leads on the basis of environmental information a corrective steering intervention by the vehicle in the lane holds. Environment information is common the lane course in front of the vehicle (curvature, curvature change) and the relative position of the vehicle in the lane (lateral distance / cross-offset, differential angle) To give the driver some freedom in choosing his position in the lane, the system sees an area around the target trajectory in that the system does not generate corrective steering wheel torques. This is the so-called non-invasive area. He leads For a vehicle movement only a certain lateral Querablage is built up before the tracking system Correctly intervenes and the vehicle back to the center moved to the roadway.

The Querablage or lateral storage, or lateral distance is the lateral Distance by the vehicle is from the target trajectory.

An LCS system has environmental sensors (eg video camera, digital map, GPS, ad-hoc networks, car-to-car communication, radar, infrared, etc.) that determine the position of the vehicle within the vehicle track can be determined, and the position, width, speed and direction of movement of environment objects in the traffic area can be determined. Possibly. This information can also be preprocessed and made available to the LKS system via an interface, or made available to the LKS system from other systems in the vehicle via an interface.

One Surrounding object can describe any object that is in the traffic area occurs. Ideally, it limits itself to the Objects for the journey and a pleasant driving experience are of interest. In this invention are in particular other Vehicles meant on neighboring lanes.

figure description

embodiments The invention is illustrated in the drawings and in the following Description explained in more detail. Show it:

1 the presentation of the initial situation and the effect of the method according to the invention,

2 an inventive steering assistance system,

3 a flow chart of the method according to the invention,

4 a torque curve adaptation,

5 the calculation of the critical longitudinal distance,

6 the calculation and evaluation of a critical condition.

In 1 Part a shows a left, fast vehicle 13 in the left lane 11 and a slow vehicle in front 14 in the right lane 12 , The vehicle 13 moves here without steering intervention of the LKS on the target trajectory 15 within the non-invasive area 16 ideal forward. The times of the positions of the vehicles are with 1 respectively. 2 circled marked.

In subfigure b has its own vehicle 13 a difference angle, that of the desired trajectory 15 leads away. The vehicle 13 describes a train 17 to the edge of the non-invasive area 16 , so until then without steering intervention, a strong approach to the neighboring vehicle at the time 2 takes place. As shown, the LKS system would start reaching the limit of the non-intrusive area 16 intervene and become a trajectory 18 to lead.

With application of the method according to the invention, the situation is as shown in part c: has the non-intrusive area at the time 1 another size as in 16 represented, it is narrowed down in recognizing the problematic situation, as in 19 shown. Due to the now narrowed non-invasive area a steering intervention of the LKS system takes place earlier than by the trajectory 18 represented and causes at the time 2 , So the overtaking time, a greater distance between the two vehicles is present than without application of the method according to the invention as shown in part figure b.

In 2 the device of a steering assistance system is shown, which contains information from environment sensor modules 21 via an input interface 22 receives and in an evaluation circuit 23 evaluates by means of the method according to the invention, if necessary, a steering intervention via the output interface 27 on a steering, or a controller 28 perform. The evaluation circuit 23 consists according to the invention of an environment detection unit 24 , an assessment module 25 which mainly performs the calculations and evaluations according to the invention, as well as an adaptation module 26 which, for example, carries out the displacement of the torque characteristic.

In 3 a flow chart is shown, which illustrates the inventive method. In a first step 31 a critical longitudinal distance X _{s is} calculated, which states at which distance the own vehicle has such a cross-stock that the comfortable transverse deposit would have just been exceeded in the event of driving past a vehicle. In parallel, in one step 32 the recognition of the environment objects carried out and by means of in step 31 calculated parameter X _s determines where the at least one object is when its own vehicle X has reached _s . In step 34 is determined by means of the parameter X _s a capture range, which states that a critical situation according to the invention is present when there would be a vehicle in this. The evaluation if that is so, finds in step 35 along with the information from step 33 instead of. If this evaluation reveals the fact that a critical situation exists, it will be in step 36 checked whether the own vehicle is left or right of the desired trajectory, which is technically equivalent to the question of whether the current operating point in 4 located in the first or third quadrant. If the own vehicle is located on the side of the desired trajectory facing away from the overtaking vehicle, then a characteristic shift into the origin can take place 37 take place as they are in 4 is explained in more detail. Otherwise, the characteristic curve can only reach the current operating point 38 be moved.

In 4 a torque curve adaptation is shown, which makes it possible to reduce the non-invasive area for the purpose of problem solving according to the invention. Here, the value Y _{0 is} shown on the X-axis, which represents the transverse deviation or lateral deviation from the desired trajectory. The desired trajectory itself must be imagined in the diagram in the origin. The steering intervention torque M caused by the LKS system is plotted on the Y axis. If Y _{0 means} a deviation to the right in the positive direction and a deviation to the left in the negative direction, a positive steering torque means a steering intervention to the left and a negative steering torque a steering intervention to the right, in order to achieve that the vehicle is returned in the direction of the desired trajectory becomes. However, it usually finds itself in a non-invasive area 41 No steering intervention instead, the torque curves are therefore zero in this area. If now the method according to the invention in the evaluation comes to the realization that the non-intervention area must be narrowed, then there is a characteristic shift 44 instead of. Depending on the position of the current operating point 42 which is in the direction 43 Now, a shift can be made to the origin as shown in sub-figure a, so that the right limit of the non-engagement area comes to rest at 45 and thus in time (before the operating point 42 reaches the value 45) no intervention-free area is no longer available. If, as shown in sub-figure b, the current operating point is already in the first quadrant, a characteristic shift in the origin would cause the steering-engagement torque to jump discontinuously, which would mean an unpleasant feeling for the driver. Therefore, it is provided that a characteristic shift only up to the current operating point 42 perform so that as shown in part figure b, the right border of the non-intrusive area at 45 would come to rest. The illustration in this figure is for the case that an environment object on the right side past the vehicle, the procedure is equally applicable to the left side, while the treatment is simply in the other quadrant instead. In addition, instead of or in addition to the characteristic shift and the shape of the characteristic curve itself be adapted, for example, the slope could be increased to cause a stronger steering intervention in a further increase in the cross-shelf.

In 5 it is shown how the critical longitudinal distance X _{s is} calculated. The transverse storage of the vehicle, that is to say the deviation of the instantaneous position of the vehicle from the desired trajectory, is marked Y ₀ . With Y ₁ is the person cross-stock marked whose size represents the transition to an unpleasant cross-shelf, if at this point an adjacent vehicle would be, if the own vehicle has reached this point. In the case of a constant or fixed, critical transverse deposition Y ₁ , a practicable value of 0.7 meters was determined empirically. However, this is to be seen as an example and can be improved by improved methods, such as the consideration of the track width. In order to determine at what distance the vehicle would have reached the transverse tray Y ₁ , assuming uniform movement without driver steering intervention, the differential angle ψ _D is still necessary, which represents the vehicle orientation with respect to the center line or desired trajectory. Taking into account a possible curve curvature (κ), which is not shown here in all figures, the critical longitudinal distance X _s can now be calculated by means of the following formula,

The choice of the sign in the formula is fixed as to whether X _{s should be determined} for the left or right neighboring lane.

In 6 the calculation and determination of a critical situation is shown geometrically, whereby in subfigure a the own vehicle on the left lane overtakes and in subfigure b on the right lane travels and is overtaken. The vehicles are analogous to 1 at two different times, the vehicle being read on the left lane at twice the speed as that traveling on the right, as well as the length of the speed vectors. The middle vehicle on the right lane in subfigure a should the right vehicle at the time 2 when it would only travel at one quarter of the speed of the left vehicle. The relative speed (V _rel ) is defined by the speed of the object (V _obj ) minus the speed of the own vehicle (V _ego ). When approaching between vehicle and object, the relative speed is thus negative. Depending on the mathematical implementation, the signs may change as well. Possibly. The relative speed can be determined directly from the environmental sensor data (eg via video image). In a following step, see 33 , It is determined where the ambient object is located when the host vehicle has reached X _s. this is done with the following formula:

The quotient component determines the time until the own vehicle has reached X _s , the multiplication with the relative speed then corresponds to the distance traveled by the environmental object in this time. Since this distance is also negative due to the negative relative speed, a subtraction of the actual distance (S _obj ) takes place and thus one obtains the longitudinal distance of the object when the own vehicle has reached X _s (X _obj ). This corresponds to the longitudinal distance from the point where the own vehicle partially points 1 is located to the point where the foreign object at the time 2 located.

Parallel will be as in step 34 characterized, the so-called capture range determined, starting from the leading distance X _s an offset X _fmax before and an offset X _fmax rearward to the distance X _s span a range, the so-called capture range. The two offsets can be constant or variable. The latter is shown in the two figures, wherein due to the speed of the catch area in sub-figure a is twice as large due to the twice as high speed of the own vehicle as in sub-figure b. Possibly. it makes sense to choose the offsets X _fmax ^and X _{fmin to be} different in size, for example if the buffer to the front should be larger. This can be found out by empirical investigations.

As for step 35 is explained here, it is now checked whether X _{obj is} in the catch range or not. Depending on this, a reaction such as in 4 described carried out according to the invention.

In subfigure a, the calculated distance is represented by X _obj2 if the environment object moves forward only at a quarter of the speed (in this case example), so that in this case no penetration into the capture area takes place and in this case no measures have to be taken. In the example shown, one's own vehicle would not drift so far to the right until the environment object has already passed. The offset X _fmin is ideally now set so that the vehicle _lengths or possibly speed changes can be taken into account, with speed changes to be uncritical, since the method according to the invention is customarily permanently applied and therefore current calculation results are available at all times. The front offset X _fmax does not have to reach forwards as from the time X _{s is reached} the LKS system would perform a steering intervention and the vehicle would move back into the center of the lane and thus the critical situation would no longer exist.

Not considered in this invention are steering interventions, which usually have a higher priority than that inventive system. Combination with procedure however, to handle driver steering interventions are readily available possible.

In subfigure b pay attention to the signs in order to apply the same formula as for subfigure a. S _obj should be negative in this case.

The application of the method as in 6 described only makes sense for relative speeds less than zero, otherwise the environment object would move away from the vehicle and there would be no need for an intervention.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10137292 A1 [0001]
• DE 102005049071 A1 [0003]

Claims (9)

Method for controlling / steering a steering assistance system (LKS) for a vehicle, - wherein an intervention-free area ( 16 . 41 ) exists, in which the LKS performs no intervention - and at least one environmental object ( 14 ), which the vehicle ( 13 ), characterized in that - the approach to the surrounding objects is evaluated ( 35 ) - and depending on it - the non-invasive area is adapted ( 44 ) - or a steering intervention takes place Method according to claim 1, characterized in that - the non-invasive area ( 16 . 41 ) is reduced such that a minimum distance to the object ( 14 ) is complied with. Method according to claim 1, characterized in that - the non-invasive area ( 16 . 41 ) is reduced ( 19 ), so that this only a fixed or relative amount to a desired trajectory ( 15 ) is wide. Method according to one of the preceding claims, characterized in that - the adaptation ( 37 . 38 ) by displacement ( 44 ) of a torque characteristic is performed Method according to one of the preceding claims, characterized in that - a size, a position and / or a risk potential of the environment objects ( 14 ) is evaluated. Method according to one of the preceding claims, characterized in that - the maximum approach to the environment object and its time / place is determined. Method according to one of the preceding claims, characterized in that - the evaluation ( 35 ) is carried out in such a way that - precalculation of the achievement of a critical cross-storage ( 31 ), and - a spatial area in front of the vehicle is determined ( 34 ), in which the at least one environment object predicts ( 32 . 35 ) must be. Steering assistance system for a vehicle, - with means for defining an intervention-free area - an interface for providing or recording an environment signal ( 22 . 27 ) - an evaluation circuit for detecting at least one environment object, which the vehicle approaches ( 24 ), characterized in that - the evaluation circuit ( 23 ) an evaluation module ( 25 ) for evaluating the approximation of the at least one object, and in that adaptation means ( 26 ) for adaptation of the non-interventional area depending on the evaluation - or that intervention means for a steering intervention ( 28 ) are provided depending on the rating. Steering assistance system according to claim 8, characterized in that that A calculation unit reaching a critical cross-stock precalculated, - and a further calculation unit determines an area in front of the vehicle, in which the at least one environment object are precalculated got to, - and the calculation results from the assessment module be taken into account.