DE102009048061A1 - Vehicle distance controlling method, involves reducing speed difference between vehicle speed and object speeds with increasing proximity to objects before reaching minimum distance - Google Patents

Abstract

The method involves determining object speeds (Vo1, Vo2) of objects (O1, O2) located in front of a vehicle (1) and object distance (a) to one of the objects directly located in front of the vehicle. Vehicle speed (v1) is set to a value during exceedance of minimum distance (am) to the object, where the value lies above the object speeds and is less than or equal to predetermined maximum speed. Speed difference between the vehicle speed and the object speeds is reduced with increasing proximity to the objects before reaching the minimum distance.

Description

The invention relates to a method for controlling the distance of a vehicle according to the features of the preamble of claim 1.

From the EP 1 426 911 A1 a device for distance control in motor vehicles is known. The device comprises a sensor device for locating objects which are located in front of the vehicle on the lane traveled by the vehicle and for measuring the distances between these objects and the vehicle. The device further comprises a control device, which engages in dependence on the measured distances in the drive and / or braking system of the vehicle. In order to calculate a minimum distance for each of the objects whose size takes into account the objects present between the object in question and the vehicle, a distance module is provided. Also, the control device is designed to comply with these minimum distances.

Furthermore, from the DE 10 2007 038 059 A1 a method for operating a distance control system for vehicles and a vehicle with a distance control system for carrying out the method known. In the method, the distance between a vehicle and a target vehicle located in front of the vehicle is regulated as a function of the traffic situation by accelerating or retarding system interventions. In this case, a forward-looking vehicle deceleration is initiated by overrun fuel cutoff and / or activation of an energy recovery system provided in the vehicle if an additional vehicle whose speed is lower than that of the target vehicle and / or that delays its travel is detected without undelayed travel of the target vehicle in front of the target vehicle.

In the DE 196 00 059 A1 For example, a method of signal processing in a motor vehicle radar assembly and a radar assembly therefor will be described. By evaluating deflected echo signals on the roadway, the method provides further information about the traffic situation in the direction of observation.

The invention has for its object to provide an improved method for adjusting the distance of a vehicle.

The object is achieved by a method for adjusting the distance of a vehicle with the features of claim 1.

Preferred embodiments and further developments of the invention are specified in the dependent claims.

In a method for adjusting the distance of a vehicle, objects are tracked in front of the vehicle on a lane traveled by the vehicle and object distances of these objects to the vehicle are determined, wherein a drive system and / or a braking system of the vehicle is controlled in dependence on the determined object distances and / or or regulated.

According to the invention, an object speed of at least one object located in front of the vehicle and an object distance to a first object located directly in front of the vehicle are determined, and if a minimum distance to the first object is exceeded, a vehicle speed of the vehicle is set to a value which is above the object speed of the at least one object and is less than or equal to a predetermined maximum speed, wherein before reaching the minimum distance, a speed difference between the vehicle speed and the object speed is reduced with increasing approach to the object.

This allows a fuel-saving and uniform driving style, since the vehicle speed of the vehicle is not controlled exclusively based on a determined distance to a preceding object and thus a constant acceleration to a predetermined target speed and then a delay in reaching a predetermined minimum distance is avoided. Furthermore, by observing further objects in front, which are located in front of the immediately preceding object, a safety gain can be realized, as a reduction in the speed of these further objects is detected immediately and the speed of the vehicle is immediately adapted accordingly, even before the directly preceding object his speed is reduced. As a result, for example, rear-end collisions in dense traffic or at a jam end are avoidable.

Embodiments of the invention will be explained in more detail with reference to drawings.

Showing:

1 a schematic representation of a vehicle and an object located in front of this, and

2 a schematic representation of a vehicle and two objects located in front of this.

Corresponding parts are provided in all figures with the same reference numerals.

1 shows a schematic representation of a vehicle 1 and one in front of the vehicle 1 located first object O1, ie a preceding vehicle another. The vehicle 1 has a sensor device 2 for detecting objects O1 on one of the vehicle 1 traveled lane FS in front of the vehicle 1 on. By means of this sensor device 2 which includes, for example, radar sensors, lidar sensors, ultrasonic sensors and / or cameras are objects O1 in front of the vehicle 1 detectable and by means of a processing unit 3 Object distances a of the objects O1 to the vehicle 1 and, for example, using a vehicle speed v _{1 of} the vehicle 1 and changes in the detected distances a, actual velocities v _{O1a of} the objects O1 can be determined. Furthermore, these speeds v _O1a and / or distances a to objects O1 in front of the vehicle 1 For example, via a so-called vehicle-to-vehicle communication detectable.

The processing unit 3 is in the example shown here with a drive system 4 and a braking system 5 of the vehicle 1 connected to control and / or to regulate and thereby adjust the vehicle speed v ₁ . As a result, for example, as components of the drive system 4 a drive motor and / or a transmission and as components of the brake system 5 a brake system and / or a device for energy recovery of the vehicle 1 controllable and / or controllable, in particular the components of the drive system 4 both to an acceleration and, in particular by a so-called overrun cutoff of the drive motor, to a deceleration of the vehicle 1 can be used.

In so-called adaptive cruise control systems according to the state of the art, in this way the vehicle speed v _{1 is determined} exclusively according to the object distance a to which directly in front of the vehicle 1 controlled first and / or regulated, wherein a minimum distance to be observed a _m , which is prescribed for example by law, and a target speed are given. This results in an uneven and uneconomical driving of the vehicle 1 in that when the object distance a is increased beyond the predetermined minimum distance a _m , it is accelerated immediately to the desired speed and when the minimum distance a _{m is reached,} the vehicle is accelerated 1 is delayed greatly.

To avoid this and the drive system 4 and / or the braking system 5 of the vehicle 1 to control and / or regulate, so that an economical, fuel-efficient and uniform driving of the vehicle 1 is made possible, the vehicle speed v ₁ is controlled in the process for distance control not only on the object distance a to the immediately preceding first object O1 and / or regulated, but also on the object speed v _O1 at least one in front of the vehicle 1 located object O1, preferably, as in 2 shown in more detail about the object speeds v _O1 , v _O2 all in front of the vehicle 1 detected objects O1, O2.

In this case, the object velocity v _O1 , v _{O2 used} is a current velocity v _O1a , V _{O28 of} the respective object O1, O2 or, as in the example shown here, a mean value of a velocity profile of the respective object O1, O2 determined over a predetermined period of time. In addition, the standard deviation of the speed profile over this predetermined period of time is preferably also determined for the respective object O1, O2. The mean and standard deviation are advantageously usable to control and / or regulate the drive system 4 and / or the braking system 5 of the vehicle 1 to smooth, ie the driving behavior of the vehicle 1 and to soften an approach to the preceding first object O1. In this way, to reduce the vehicle speed v _1, for example, only disengage the transmission and the vehicle 1 idling to run or to use a so-called overrun fuel cutoff, so that the brake system of the vehicle 1 can be spared and a fuel consumption is reduced. Is a device for energy recovery in the vehicle 1 This is also advantageous for reducing the vehicle speed v _{1 of} the vehicle 1 used.

Im in 1 the first embodiment of the method, the speed profile of the first object O1 is determined over a predetermined period of time, for example ten minutes, and from this an average value and a standard deviation of the speed are determined. Furthermore, an average value and a standard deviation of the object distance a can advantageously also be determined over this time span. The method is explained below with reference to an example.

The current speed V _{O1a of} the first object O1 is 80 km / h in the example shown here, the determined mean value of the speed profile of the first object O1 over the predetermined time period, which is advantageously used as the object speed v _O1 , is 75 km / h with a determined Standard deviation of 7 km / h. The object distance a to the first object O1 is 100 m. The predetermined maximum speed, which must not be exceeded, is 90 km / h. For example, this maximum speed is a legally prescribed maximum speed for a truck. Furthermore However, this maximum speed can also be, for example, a setpoint speed predetermined by a vehicle driver. The minimum distance a _m , which must not be fallen below, for example, a legally prescribed for this speed range minimum distance a _m and is for example 40 m.

In the prior art, the drive system would 4 and the brake system 5 of the vehicle 1 now so controlled and / or regulated that the vehicle 1 would be accelerated to the maximum permissible speed and would be greatly delayed on reaching the minimum distance a _m . Such uneven driving results in increased fuel consumption and brake wear.

By means of the method becomes the drive system 4 and / or the braking system 5 of the vehicle 1 controlled in the example shown here and / or regulated so that the vehicle speed v ₁ of 85 km / h initially, that is maintained for 36 seconds, so that the vehicle 1 approaches the first object O1, since the vehicle speed v _{1 is} both greater than the current speed v _{O1a of} the first object O1 and greater than the mean value of the speed profile of the first object O1 used as the object speed v _O1 .

Within these 36 seconds the vehicle approaches 1 in this way relatively quickly to the first object O1 up to an object distance a of 50 m. However, this object distance a is still greater than the predetermined minimum distance a _m , so that a strong reduction of the speed v ₁ is not yet required. Nevertheless, even now, ie at an object distance a of 50 m, the speed v _{1 of} the vehicle 1 by a control and / or regulation of the drive system 4 and / or the braking system 5 reduced to a speed v ₁ of, for example 81 km / h. This can for example be done solely by a fuel-saving use of fuel cut, by disengaging the transmission and / or by using the device for energy recovery, since there is still a sufficiently large object distance a.

With this reduced speed v _{1 of} the vehicle 1 from 81 km / h is then a slow and gentle further approach of the vehicle 1 to the preceding first object O1. As a result of this slow and gentle approach, once the minimum distance a _{m has been reached} again, only a relatively small control and / or regulation of the drive system is achieved 4 and / or the braking system 5 required, so that a gentle, gentle and even driving of the vehicle 1 is possible, with a consequent reduction in fuel consumption and brake wear and, if possible, advantageously with recuperation of energy.

If the standard deviation of the speed profile of the first object O1 is greater than in this example, ie the first object O1 is moving at a strongly fluctuating current speed v _O1a , then the vehicle speed v _{1 of} the vehicle becomes 1 Reduced correspondingly earlier to a sufficient object distance a to the vehicle 1 and also in this case a slower approach of the vehicle 1 with a reduced vehicle speed v ₁ to allow the first object O1. As a result, in particular, a sudden undershooting of the minimum distance a _m due to a suddenly sharply decreasing current speed v _{O1a of} the first object O1 is to be prevented, since this is a sudden strong deceleration of the vehicle 1 would require.

Increases the current speed v _{O1a of} the first object O1 after the approach of the vehicle 1 to the minimum distance a _m again, so the object distance a initially increases again over the minimum distance a _m , which analogously to the described procedure again a new vehicle speed v _{1 is} determined which, for example, at a relatively small object distance a, for example only slightly larger than the minimum distance a _m , would be only slightly above the object speed v _O1 to again slow the vehicle 1 to allow the first object O1.

If the actual speed v _{O1a of} the first object O1 fluctuates greatly, ie if there is a large standard deviation of the speed profile, the vehicle speed v _{1 is} preferably initially maintained. This method thus allows a very smooth driving with only small changes in speed, preferably without a use of the brake system and with a minimum of energy use, preferably to maintain only a constant vehicle speed v ₁ . This is particularly advantageous in a so-called column traffic.

2 shows a further embodiment of the method. In this example you are in front of the vehicle 1 two of the sensor device 2 of the vehicle 1 detectable objects O1, O2, the first object O1 directly in front of the vehicle 1 and another object O2 in front of the first object O1. The further object O2 is in this case for example by means of a high on the vehicle 1 arranged camera system as a sensor unit 2 or by sensors of the sensor unit 2 on the outside of the vehicle 1 are arranged, detectable. Captured in this way the sensor unit 2 the further object O2 past the first object O1 or laterally past it.

In a further advantageous embodiment, the sensor unit comprises 2 Radar sensors pointing to a roadway in front of the vehicle 1 are directed, via a reflection of radar signals on the road, the radar signals below the first object O1 through the other object O2 can reach and reflected by this, reach the radar sensors again via the reflection on the road. This is in the older application DE 196 00 059 A1 the applicant discloses. Furthermore, as already mentioned, for example, it is also possible to determine the speed of the objects O1, O2 via vehicle-to-vehicle communication.

In the means 2 explained advantageous embodiment of the method, the drive system 4 and / or the braking system 5 of the vehicle 1 in such a constellation with a plurality of the sensor unit 2 detected objects O1, O2 according to the object speed v _O1 , v _{O2 of} the slowest detected object O1, O2 controlled and / or regulated. In the exemplary embodiment illustrated here, an average value of the velocity profile of the further object O2, which is used as the object velocity v _{O2 of} the further object O2, is less than an average value of the velocity profile of the first object O1, which is used as the object velocity v _{O1 of} the first object O1. The minimum distance a _{m of} the vehicle 1 to the first object O1 is exceeded.

Ie. the lowest object velocity v _O1 , v _O2 , after which the drive system 4 and / or the braking system 5 of the vehicle 1 to be controlled and / or regulated, is the object velocity v _{O2 of} the other object O2. The object distance a, after which the drive system 4 and / or the braking system 5 of the vehicle 1 to control and / or is to regulate, but is always the object distance a to the directly in front of the vehicle 1 moving first object O1, since the predetermined minimum distance a _m to this first object O1 must not be exceeded for safety reasons.

This embodiment of the method is particularly advantageous in a convoy traffic or in a congested traffic, since thereby an additional security gain can be realized. Because the drive system 4 and / or the braking system 5 of the vehicle 1 always after the lowest object speed v _O1 , v _O2 all of the sensor device 2 detected objects O1, O2 is controlled and / or regulated, a reduction of the current speed v _O2a in particular of the other object O2, for example, at a tail end very early detected, even before the current speed v _O1a of immediately before the vehicle 1 moving first object O1 is reduced. In this way, for example, a collision at a jam end can be prevented. Furthermore, in a convoy traffic not only fast on the ramp in front of the vehicle 1 driving first object O1, but also a quick startup with this first object O1 together prevents the further object O2.

Since the vehicle speed v _{1 is} controlled and / or regulated according to the lowest object speed v _O1 , v _O2 , ie in the example illustrated here according to the object speed v _{O2 of} the further object O2, this can lead to the object distance a of the faster first object O1 to the vehicle 1 temporarily increased until the first object O1 accumulates on the further object O2 and then slowly decreases. This enlargement of the object distance a would in the case of prior art methods lead to an immediate, strong acceleration of the vehicle 1 lead, with an increased fuel consumption, and at a collision with the first object O1 on the further object O2 to a strong delay, associated with increased brake wear.

This is avoided by means of the procedure, so that the vehicle 1 moves very uniformly in such a column traffic, advantageously with a constant or nearly constant vehicle speed v ₁ and slowly approaching the first object O1 and the further object O2 while maintaining the minimum distance a _m . As a result, in particular interventions of the brake system of the vehicle 1 avoided or significantly reduced and avoided strong accelerations. This results in reduced fuel consumption and reduced brake wear.

LIST OF REFERENCE NUMBERS

1

vehicle

2

sensor device

3

processing unit

4

drive system

5

braking system

O1

first object

O2

another object

FS

lane

a

object distance

a _m

minimum distance

v ₁

vehicle speed

V _O1

object speed

V _O2

object speed

V _O1a

current speed

V _O2a

current speed

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

• EP 1426911 A1 [0002]
• DE 102007038059 A1 [0003]
• DE 19600059 A1 [0004]
• DE 19600059A [0031]

Claims (3)

Method for adjusting the distance of a vehicle ( 1 ), wherein with a sensor device ( 2 ) Objects (O1, O2) on one of the vehicle ( 1 ) traffic lane (FS) in front of the vehicle ( 1 ) and object distances (a) of these objects (O1, O2) to the vehicle ( 1 ) and wherein, depending on the determined object distances (a), a drive system ( 4 ) and / or a braking system ( 5 ) of the vehicle ( 1 ) is controlled and / or regulated, characterized in that an object speed (v _O1 , v _O2 ) at least one in front of the vehicle ( 1 ) (O1, O2) and an object distance (a) to a directly in front of the vehicle ( 1 ) is determined and when a minimum distance (a _m ) to the first object (O1) exceeds a vehicle speed (v ₁ ) of the vehicle ( 1 ) is set to a value which is above the object speed (v _O1 , v _O2 ) of the at least one object (O1, O2) and less than or equal to a predetermined maximum speed, wherein before reaching the minimum distance (a _m ) a speed difference between the vehicle speed (v ₁ ) and the object speed (v _O1 , v _O2 ) with increasing approach to the object (O1, O2) is reduced. A method according to claim 1, characterized in that in other objects (O2) in front of the vehicle ( 1 ) the object speeds (v _O1 , v _O2 ) all by means of the sensor device ( 2 ) detected objects (O1, O2) are determined and the vehicle speed (v1) to the lowest object speed (v _O1 , v _O2 ) controlled and / or regulated. A method according to claim 1 or 2, characterized in that a speed profile of the objects (O1, O2) is detected over a predetermined period and for each detected object (O1, O2), an average value and a standard deviation of the velocity profile is determined, wherein as object speed ( v _O1 , v _O2 ) for the respective object (O1, O2) the respective mean value of the velocity profile of the object (O1, O2) is used.

Images