DE102012007197A1 - Method for adaptive speed control of vehicle, involves introducing acceleration of vehicle after target object loss after expiry of constant holding phase, during which driving speed of vehicle is constantly held - Google Patents

Abstract

The method involves introducing the acceleration of a vehicle after the target object loss after the expiry of a constant holding phase, during which the driving speed (V-ist) of the vehicle is constantly held on the value of the actual driving speed for time point of the target object loss. The constant holding phase takes long until the predetermined desired speed (V-soll) is confirmed by the driver or the driver requests a new desired speed.

Description

The invention relates to a method for adaptive cruise control according to the features of the preamble of claim 1.

Such a method is known from DE 100 04 525 A1 known. In this method for controlling the travel speed of a motor vehicle and the distance of the motor vehicle to at least one preceding vehicle, the driving speed of the motor vehicle and the distance to the vehicle in front are determined and upon detection of a deviation between the determined distance and a predetermined desired distance, the motor vehicle is decelerated or accelerated to regulate the distance to the target distance.

Furthermore, from the DE 10 2007 018 990 A1 a method for automatic longitudinal speed control is known, in which the driving speed of a vehicle is controlled by evaluating information about distances to other vehicles and about the particular characteristics of each track a lane. In particular, it is detected on the basis of lane markings, whether the vehicle is located on a motorway exit or highway entrance and when driving on a motorway exit or highway entrance modified or permitted modified compared to a ride on ordinary lanes modified parameters.

From the DE 103 55 220 A1 A method is known for limiting the speed of a vehicle, in which the driving speed of the vehicle is limited depending on the position of the vehicle. In this case, depending on the position of the vehicle, a limit speed is stored together with the current position of the vehicle and when this position is reached again, the driving speed of the vehicle is automatically limited to the stored limit speed.

The invention has for its object to provide a comparison with the prior art in terms of ride comfort improved method for an adaptive cruise control. The object is achieved by a method having the features of claim 1.

According to the invention, in an adaptive cruise control method in which the current vehicle speed of the vehicle is adjusted to the speed of a preceding vehicle selected as the target, the vehicle follows the target at a predeterminable target distance, and the vehicle after a target loss is provided that the acceleration of the vehicle after the Zielobjektverlust begins after expiration of a constant hold phase, wherein the vehicle speed in the constant hold phase on the value of the current at the time of target loss driving speed is constant, and wherein the constant hold phase continues so long, until the predetermined target speed is confirmed by the driver or until the driver requests a new target speed or until a situation evaluation shows that the predetermined target speed is lower or lower it is equal to a maximum speed limit. The acceleration of the vehicle is thus suppressed during the constant-maintenance phase.

The target object loss, d. H. the loss of the preceding vehicle selected as the target object occurs, for example, when the target object leaves the lane of the vehicle or when the vehicle leaves the lane of the target object.

The driver can confirm the desired speed via an input unit, for example by pressing an accelerator pedal or a cruise control unit.

With the method, an adaptive cruise control is possible, without resulting in a safety-critical situation after a target object loss, because the vehicle is accelerated only after a driver-side action that may include a confirmation of the predetermined target speed or a request for a new target speed.

In a further advantageous development of the method, the setpoint speed is predetermined by the driver.

It is also advantageous if the permissible maximum speed is determined by an environment detection system or by card attributes of a digital map. Thus, the permissible maximum speed of the adaptive cruise control can be provided quickly and reliably. The environment detection system may be, for example, a camera for traffic sign recognition in the vehicle.

The card attributes of a digital map can be processed, for example, by a navigation device. Among other things, the card attributes originate from a storage medium such as a CD or are provided by a network interface.

A critical driving situation can be avoided if the vehicle is accelerated to the target speed only if the target speed is confirmed by the driver or if the target speed is less than or equal to the permissible maximum speed.

It is advantageous if the desired distance to the target object corresponds to a time gap or a distance that can be varied within certain limits by the driver.

The time gap is the time interval required by the vehicle to reach the current position of the target object.

The automatic maintenance of a target distance relieves the driver, incidentally, the safety of the vehicle and the driver, since the system acts too close to a collision with another road user.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. On the one hand, reference should be made to the subordinate claims and, on the other hand, to the following explanation of an embodiment. It should also be included the advantageous embodiments resulting from any combination of subclaims. In the figures, embodiments of the method according to the invention are shown.

Show it:

1 a schematic representation of a first embodiment of the method according to the invention,

2 a schematic representation of a second embodiment of the method according to the invention,

3 a schematic representation of a third embodiment of the method according to the invention.

A first embodiment of the method according to the invention, 1 , can proceed as follows.

If the driver wishes his vehicle _to move at a specific setpoint speed V _soll , then in a first method step S1 by means of an input unit, for example actuation of the accelerator pedal or a cruise control operating unit, he can predetermine this setpoint speed V set as the adaptive cruise control device speed _to be adjusted ,

In a second method step S2, the adaptive cruise control device then regulates the current vehicle speed V _ist to the predefined desired speed V _soll .

Thus, there is no collision with a slower vehicle ahead, after a specific first time period T1 in a third step S3, the current distance A _is to the preceding vehicle by a distance sensor, such as a radar system queried.

The instantaneous distance _is A is then set to a first distance A _to (1) is compared in a fourth method step S4. The first desired distance A _soll (1) is stored, for example, in a memory or it is calculated as a function of the instantaneous situation, for example as a function of the vehicle speed V _ist or a relative speed between the vehicle and the vehicle in front.

If the comparison in the fourth method step S4 shows that the instantaneous distance A _{ist is} greater than the first setpoint distance A _soll (1), the method branches to the method step S2. Thus, as long as the instantaneous distance A _is greater than the first predetermined distance A _is (1) the vehicle speed V _{is intended} to desired by the driver set speed V adjusted.

On the other hand, if the comparison in the fourth method step S4 shows that the instantaneous distance A _is smaller than the first setpoint distance A _soll (1), a branch is made to a fifth method step S5.

In the fifth method step S5, the adaptive cruise control device adjusts the vehicle speed V _ist as a function of a second setpoint distance A _soll (2) such that the vehicle follows the preceding vehicle, referred to below as the target object, at a distance A which _is the second setpoint distance A _soll (2) corresponds. That is, there is carried out a distance control, in which the distance A _{is intended} to the target object to the desired distance A (2) is regulated. The second nominal distance A _is (2) as the first nominal distance A _{is to} be deposited, for example, in a memory (1) or it is depending on the situation, for example in dependence of the vehicle speed V or the relative speed between the vehicle and the target object _is calculated. In the transition from the fourth method step S4 to the fifth method step S5, the operating mode of the adaptive cruise control device is thus de facto changed from a constant-speed control to a distance control.

Subsequent to the fifth method step S5, after a predetermined second period of time T2 has elapsed, a sixth method step S6 checks whether the instantaneous distance A _{ist is} smaller than the first setpoint distance A _soll (1). If this is the case, a branch is made back to method step S5. Accordingly, the adaptive cruise control device performs distance control as long as the instantaneous distance A _is smaller than the first target distance A _soll (1).

In order to increase the comfort for the driver, the first nominal distance A is _to (1) selected so that it is greater than the fluctuations in the instantaneous distance A _is to be expected in a conventional today distance control.

If the test in the sixth method step S6 shows that distance A _is not smaller than the first setpoint distance A _soll (1), then there is a target object loss and a branch is made to a seventh method step S7.

In the seventh method step S7, the vehicle speed V _{ist of} the vehicle is kept constant. The vehicle therefore continues to travel at the current driving speed at the time the target object is lost. In the seventh method step S7, it is also cyclically checked whether there is a driver confirmation by which the driver confirms that the vehicle _should accelerate to the setpoint speed V _soll specified in the first method step S1 or to a newly entered setpoint speed. The driver confirmation can be done by pressing the accelerator pedal or the cruise control unit. If there is no driver confirmation within a predefinable third time period T3, the system branches to an eighth method step S8, otherwise a branch is made back to method step S2.

In the eighth method step S8, the current vehicle speed V _ist at the time of the target object loss _{is used} as the target speed of the adaptive cruise control and the method is continued with the second method step S2.

The driver can deactivate the method at any time by actuating the cruise control unit or by a brake operation or restart by entering a new desired speed with the first method step S1.

A second embodiment, as in 2 is different from the first embodiment in the seventh method step S7 '. In the seventh step S7 'in the second embodiment, the change made to this point in the first embodiment test is whether a driver is confirmed, replaced by a test whether the target speed V _to less than or equal to a local speed limit V _permitted. The permissible maximum speed V _permissible can be determined, for example, by an environment detection system by traffic sign recognition and / or from map attributes of a digital map.

A_ist

momentaner Abstand

A_soll(1)

erster Sollabstand

A_soll(2)

zweiter Sollabstand

V_ist

momentane Fahrgeschwindigkeit

V_soll

Sollgeschwindigkeit

V_zulässig

zulässige Höchstgeschwindigkeit

S1

erster Verfahrensschritt

S2

zweiter Verfahrensschritt

S3

dritter Verfahrensschritt

S4

vierter Verfahrensschritt

S5

fünfter Verfahrensschritt

S6

sechster Verfahrensschritt

S7, S7', S7''

siebter Verfahrensschritt

S8

achter Verfahrensschritt

A third embodiment, as in 3 is different from the first embodiment and the second embodiment in the seventh method step S7 ". In the seventh method step S7 "of the third embodiment, the check made at this point in the first embodiment as to whether there is a driver's confirmation is replaced by a check as to whether the driver's confirmation exists or if the target speed V _{soll is} less than or equal to the local maximum permissible speed V _{is permissible} . Accordingly, the test criteria made at this point in the first and second embodiments are combined by an OR operation.

A _is

current distance

A _should (1)

first nominal distance

A _should (2)

second desired distance

V _is

current driving speed

V _should

target speed

V _allowed

speed limit

S1

first process step

S2

second process step

S3

third process step

S4

fourth process step

S5

fifth process step

S6

sixth process step

S7, S7 ', S7''

seventh process step

S8

eighth process step

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10004525 A1 [0002]
• DE 102007018990 A1 [0003]
• DE 10355220 A1 [0004]

Claims (4)

Method for adaptive cruise control of a vehicle, in which an actual driving speed (V _ist ) of the vehicle is adapted to the speed of a preceding vehicle selected as the target, such that the vehicle follows the target at a predefinable desired distance (A _soll (2)), - and in which the vehicle to a target object loss to a predetermined target speed (V _soll) is accelerated, characterized in that the acceleration of the vehicle after the target object loss starts only after the lapse of a constant holding phase during which the travel speed _(V) of the vehicle on the Value of the current driving speed is maintained constant at the time of the Zielobjektverlusts, and that the constant-maintenance phase lasts until - the predetermined target speed (V _soll ) is confirmed by the driver or - until the driver requests a new target speed (V _soll ) or - until a Situationsbew ertung shows that the preset desired speed (V _soll) is less than or equal to a permitted maximum speed (V _permitted) is. Method according to the preceding claim, characterized in that the target speed (V _soll) is predefined by the driver. Method according to claim 1 or 2, characterized in that the permissible maximum speed (V _permissible ) is determined by an environment detection system by traffic sign recognition and / or from map attributes of a digital map. Method according to one of the preceding claims, characterized in that the desired distance (A _soll (2)) is specified as a certain time gap or as a certain distance.

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