WO2006056354A1

WO2006056354A1 - Traffic-adaptive assistance system

Info

Publication number: WO2006056354A1
Application number: PCT/EP2005/012289
Authority: WO
Inventors: Boris Kerner
Original assignee: Daimlerchrysler Ag
Priority date: 2004-11-26
Filing date: 2005-11-16
Publication date: 2006-06-01
Also published as: DE102004057147A1

Abstract

The invention relates to a method for controlling a traffic-adaptive assistance system in a vehicle by means of the speed-related or distance-related variables of said vehicle and a preceding vehicle. The assistance system causes an acceleration or deceleration of the vehicle with the aid of said variables. To control the vehicle no target variables are used in certain value ranges of actual variables. The invention is characterised in that no acceleration or deceleration of the vehicle is planned in the longitudinal direction, if the difference between the actual time interval and a target time interval is less than a predefinable, speed-dependent value and/or if the difference between the vehicle concerned and the speed of the preceding vehicle is less than a predefinable, speed-dependent value.

Description

TRAFFIC ADAPTIVE ASSISTANCE SYSTEM

The invention relates to a method for controlling a vehicle-mounted traffic-adaptive assistance system with speed-related and / or distance-related variables of the vehicle and of a preceding vehicle, wherein the assistance system causes acceleration or deceleration of the vehicle using these variables, and wherein certain ranges of values of actual variables no target variables are used to control the assistance system. Here, actual quantities are current quantities, e.g. the current speed of the vehicle, and targets of desired sizes, for example, a distance to be set to the vehicle in front.

Such a method is proposed by the applicant in DE 103 08 256 Al.

As is known, an assistance system which is particularly comfortable for the driver results if the response of the assistance system (ie the acceleration or deceleration of the vehicle) to the difference between the actual time interval and the target time interval or to the difference between the time interval own speed and the speed of the vehicle in front is particularly "slow" (ie small acceleration or deceleration values of the vehicle) aus¬ falls .This, however, means that for safety reasons usually a relatively large distance to the vehicle in front is provided which makes it easy for other vehicles to engage and thus disturb the driver, Furthermore, it has been shown that a sequence of vehicles with such "slow" assistance systems is unstable. This instability leads to the emergence of moving congestion in traffic when the proportion of vehicles with "slow" assistance systems is greater than a critical value, see BS Kerner, "The Physics of Traffic" (Springer, Berlin, New York 2004).

In contrast, a sequence of vehicles with "fast" assistance systems (ie the assistance system responds to the difference between the actual time interval and the target time interval or to the difference between the own speed and the speed of the vehicle ahead with a relative This means that such "fast" assistance systems counteract the development of moving congestion in traffic. As a result, no moving traffic jams occur in traffic when the proportion of vehicles with "fast" assistance systems is greater than a critical value.Also, a smaller distance to the vehicle ahead prevents the constant collapse of other vehicles "Assistance systems for the driver not very comfortable. For while a vehicle driver himself accepts selected relatively large acceleration or deceleration values, such values are rejected if they are set automatically, ie by the assistance system. The object of the invention is to specify a method for controlling a traffic-adaptive assistance system located in a vehicle, which increases driving comfort without jeopardizing traffic safety, and which counteracts the development of moving traffic jams in traffic.

The object is achieved in each case by the features of the two independent, independent claims 1 and 2. The subclaims relate to advantageous embodiments and further developments of the invention.

According to the invention, no acceleration or deceleration of the vehicle in the longitudinal direction is provided if the difference between the actual time interval and a target time interval is smaller than a predeterminable, speed-dependent value. It is also provided according to the invention that no acceleration or deceleration of the vehicle in the longitudinal direction is provided if the difference between the own speed and the speed of the vehicle in front is smaller than a predeterminable, speed-dependent value.

The main idea of the invention is that, in certain cases, there is no reaction to a change in the current time interval and / or the speed difference between the vehicle and a preceding vehicle, namely if the difference hisses the current time interval and a desired time interval or the difference between the own speed and the speed of the vehicle driving in front is smaller than a function dependent on the vehicle speed. To ensure road safety this will preferably provided at relatively low vehicle speeds. This results in a particularly comfortable and energy-saving control of the assistance system by not responding to the smallest changes between the vehicles and accordingly the assistance system is controlled. Furthermore, the stability of transport is increased by the use of such vermehr¬ th of driven assistance systems significantly ^"storage by the emergence of danger is reduced.

While usually for. Control of traffic-adaptive assistance systems (control) in the "effects" of the scheme is set, for example, by an acceleration determined by the traffic-adaptive assistance system in a first step is then limited in a second step, the invention begins earlier. The invention attacks the "causes" by directly looking at the quantities provided for controlling the traffic-adaptive assistance system in order to check whether a acceleration or deceleration in the longitudinal direction is to be provided. Thus, the invention combines the advantages of a human being (driver), namely not reacting to a slight change in the current time interval and / or the speed difference between the vehicle and a preceding vehicle in dense traffic, with the advantage of a machine (assistance system), namely without Response time to respond immediately. This results in a particularly comfortable assistance system, since the time "gained" by the missing reaction time can be converted into a correspondingly lower set acceleration or deceleration, given necessary changes, because there is more time for the acceleration or deceleration process to disposal.

Preferably, to select the speed-dependent value, a distinction is made as to whether the actual time interval is greater than that Target time interval or less than the target time interval is and / or if the own speed is greater or less than the speed of the preceding vehicle. This allows a particularly secure assistance system.

The inventive idea can be realized by various combinations. Thus, for example, either only the difference between the current time interval and a desired time interval or the difference between the own speed and the speed of a preceding vehicle can be taken into account. Alternatively, it is envisaged that any combination of these sizes is used. Each implementation form can use its own vehicle speed, the speed difference between the own vehicle and the vehicle ahead, and / or the current time interval for activating the assistance system.

In a particularly preferred embodiment, it is provided that a specific, specifiable vehicle speed is provided which, when exceeded by the assistance system, uses a constant target time interval to the vehicle in front. This time interval is predetermined, for example, by the driver in a conventional manner. If the vehicle has a speed that is less than this speed, then instead of this constant, a variable target interval is used. The variation of the target time interval may in particular depend on the speed of the vehicle, the current time interval and / or the speed difference of the vehicle to the vehicle in front.

Preferably, the variation of the desired time sweep occurs in the form of a reduction, wherein the reduction with becomes smaller and smaller actual distance and / or decreasing actual speed and / or increasing Differenzgeschwin¬ speed is increased.

Again, any combinations are provided between either a difference between the actual time interval and the target time interval and / or a difference between the actual speed and the speed of a preceding vehicle.

In the case of using the difference between the own speed and the speed of a preceding vehicle, it is preferably additionally provided that when the vehicle speed exceeds a certain speed threshold, the reaction of the vehicle to the difference between its own speed and the speed of the preceding vehicle is reduced ver¬.

In one embodiment of the invention, it is provided that a desired target time interval, which is predetermined, for example, by the vehicle driver, is only varied if the difference between the speed of the driver's vehicle and that of the vehicle ahead is less than or equal to zero. Alternatively or additionally, it can be provided that the differential speed is moved accordingly. This results in a comfortable and very safe control.

In one embodiment of the invention, it is provided that the respective variation is made on other lanes depending on the mean time intervals. This results in a particularly well adapted to the specific situation regulation. The middle Zedtabstände on other lanes can in this case, for example, measured by the vehicle or transmitted by other vehicles by vehicle-vehicle communication.

The invention will now be illustrated with reference to a drawing. The single FIGURE shows a particularly preferred embodiment of the invention.

In traffic adaptive assistance systems, for example ACC (automatic cruis.e control) or stop-and-go assistance system, the acceleration or deceleration ^a "(n is the time) of the vehicle is a function of the difference between the actual time interval (current time interval ) to the preceding vehicle

Vehicle, ^τ n ⁼ v " ^x n ^{~ d)} ' ^v n, the target time interval (desired

Time interval) to the vehicle ahead, ^TACC , and the difference in vehicle ^speeds :

(D with K ^τ and K ^v as dynamic coefficients of the

Assistance system, ^{f> n} as the speed of the vehicle ahead, d as the vehicle length. If

(2) and ^τ " ^{= τACC} , (3) so ^a n ^~ and a time interval ^ACC (indicated as a constant or as a function of the vehicle ^speed or vehicle speeds) is traveled with a distance to the preceding vehicle from _{( 4)}

Now, the dynamic coefficient ^{τ is set} depending on whether the actual vehicle speed is less than a v predetermined vehicle speed ^p and the difference τ _n -τ _ACC between the actual time interval ^τ n and target time interval

^{ACC is} outside a time range whose limits depend on the vehicle speed and / or whether τ _n -τ _{ACC is} greater or less than zero. Alternatively or additionally, the dynamic coefficient K _{v is set} depending on whether the actual vehicle speed is less than the y predeterminable vehicle speed P and the difference v _{f π} -v _n between the speed of the vehicle ahead

Vehicle v _{C n} and the vehicle speed V _n outside a speed range whose limits are _dependent on the vehicle speed and / or whether V _jn -V _{n is} greater or less than zero. For example, this can be realized as shown below:

where the dynamic coefficient K _τ (v _n , v _en -v _n , τ _n , τ "-τ _ACC ) a

Function of ^v °, ^e < ⁿ ", ^τ π and / or τ _n -τ _ACC can be and the dynamic coefficient K _v \ y _a , v _eπ ~ v _n , τ _n ) a function of

^v n, ^{e> nn} and / or ^Tn . In addition, in (5), the target time interval ^{ACC may be} a function of ^v ", '•" ⁿ and / or ^τ n. In particular, ^{ACC is} one, eg by the

- (0)

Driver specified, constant ^ACC only if the vehicle speed is greater than a predetermined

Vehicle ^{speed Vm} is, ie,

In certain applications, the function in (6) may correspond to the following relationship

(7a)

If ^{ACC is} smaller than a predetermined value, in (6), unlike (7a), ( ^7b >

for example, if the value of τ ^{A (0C) C} in free traffic has been chosen to be very small and is now too small for dense traffic.

In addition, it can be provided in (5) that the function

^K τ = ^K τ ( ^V n> ^v f, n ^-v n> ^τ n> ^τ n ^-τ ACC), the larger the small ^v "and / or ^τ n are, e.g.

^{( 8th)}

Alternatively or additionally, in (5) can be provided

_{9}

where ^v and K _j ^{0) are} given constants and ^v <"and v _{t are} given vehicle speeds For certain applications, the functions K _τ and K _v in (8), (9) may correspond to the following relationships (10)

According to (5), at lower vehicle speeds, the vehicle will neither accelerate nor decelerate as long as the difference T _n -τ _ACC and / or the difference w _(n -V _n within the ranges determined by (5) are determined Moreover, at lower vehicle speeds, this allows relatively large values of the dynamic coefficients K _v and K _t to be used in order to prevent the development of moving congestion without endangering ride comfort.

By (6), (7) it is possible to operate the traffic-adaptive assistance system at all vehicle speeds and so relieve the driver: At

(0) Vehicle ^speeds greater than ^Vm become ^ACC ~ ^ACC , at smaller vehicle ^{speeds ACC} can be reduced. In addition, by (8) - (10), the vehicle's response to the difference τ _n -τ _ACC and / or the difference V _j1n -V _{n is} significantly increased if the vehicle speed is small. In (5) it can also be provided that for smaller

Vehicle speeds τ ^ACC and / or K _τ and / or K ^v of

the corresponding constants ^{ACC ~ Acc} or K _x = Kf,

K ^v = K ^ ^{v is} deviated, depending on whether v ^€ "^{> n} -v ^{π is} negative or positive:

Alternatively or additionally, it may also be provided in (5) that at lower vehicle ^{speeds TACC} and / or K _x

and / or K ^v of the corresponding constants τ ^ACC = τ ^{(A0C) C} or

K _t = K _τ ⁰⁾ , ^{κv = κv} , depending on whether τ _n -τ _{ACC is} negative or positive:

can depend on the mean time intervals on the other lanes (j = 1, 2,...), which are measured by the vehicle, for example, where "i" is the vehicle's own vehicle lane. - (28) in (5) - (22) may also depend on the characteristics of the traffic (ie the temporal-spatial distribution of the vehicle density, the time intervals and the vehicle speed) downstream of the vehicle, if dynamic information on these characteristics are present in the vehicle.

Claims

claims

A method for controlling a vehicle-mounted traffic-adaptive assistance system with speed and / or distance-related variables of the vehicle and a vehicle in front, wherein the assistance system using these variables causes an acceleration or deceleration of the vehicle, and wherein in certain ranges of values of - Parameters used to control the assistance system no target variables are characterized in that no acceleration or deceleration of the vehicle is provided in the longitudinal direction, when the difference between the actual time interval and a target time interval is smaller than a predeterminable, speed-dependent value.

2. A method for controlling a vehicle located in a traffic-adaptive assistance system with speed and / or distance-related sizes of the vehicle and a preceding vehicle, wherein the assistance system using these variables causes acceleration or deceleration of the vehicle, and wherein in certain ranges of values of - QEußerii sfUir driving system of the assistance system none Target variables used are characterized in that no acceleration or deceleration of the vehicle is provided in the longitudinal direction, when the difference between the own speed and the

Speed of the vehicle in front is less than a predeterminable, speed-dependent value.

3. The method of claim 1 or 2, wherein as an additional condition that no acceleration or deceleration of the vehicle is provided in the longitudinal direction, a relatively low vehicle speed is provided.

4. The method according to any one of the preceding claims, wherein the speed-dependent value is selected depending on whether the actual time interval is greater than the target time interval or less than the target time interval and / or whether the own speed is greater or less than the speed of the preceding vehicle.

5. The method according to any one of the preceding claims, wherein a certain, predetermined vehicle speed is provided, when exceeding the assistance system, a target time interval is used to the vehicle in front.

6. The method of claim 5, wherein when falling below the determined, specifiable vehicle speed, a reduction of the target time interval is provided.