DE102019113724A1 - Method for dynamically adjusting the longitudinal spacing of vehicles - Google Patents

Abstract

The invention relates to a method in which the longitudinal distance (d) between motor vehicles driving one behind the other, namely an ego motor vehicle (12) and a motor vehicle immediately ahead of it, is dynamically adapted depending on the performance of the service brake of the ego motor vehicle (12), with At least the preceding motor vehicle (10) is a member of an electronically coupled vehicle convoy (1) in which the motor vehicles (2, 4, 6, 8, 10) of the vehicle convoy (1) based on a predeterminable overall operating strategy assigned to the vehicle convoy (1) (Conveyor controller) are moved along a route, and in which in the ego motor vehicle (12) a characteristic curve or a map is first stored, which or which a course of the desired decelerations to be achieved by the ego motor vehicle (12) (asoll ) as a function of various braking requirements (p) for the service brake of the ego motor vehicle (12) forms, the method further comprising at least the following detection and checking steps and then the longitudinal distance (d) between the ego motor vehicle (12) and the motor vehicle (10) immediately ahead is detected, and it is checked whether a the service brake has been triggered in the ego motor vehicle (12), and if this is the case, a deceleration check is used to check whether the amount of the actual deceleration (aist) of the ego motor vehicle (12) during this braking is greater than or equal to or less than the amount of a target deceleration (asoll), which the ego motor vehicle (12) would have to achieve according to the stored characteristic curve or the stored characteristic field if it were to respond to the braking request (pbrems) present during braking is braked, and then the longitudinal distance (d) between the ego motor vehicle and the motor vehicle (10) immediately ahead of it is dependent on e Adjusted a result of the delay review.

Description

The invention relates to a method in which the longitudinal distance between motor vehicles driving one behind the other, namely an ego motor vehicle and a motor vehicle immediately ahead of it, is dynamically adapted depending on the performance of the service brake of the ego motor vehicle, according to claim 1.

Using the driver assistance systems available in modern motor vehicles, driving in an electronically coupled vehicle convoy can be automated at least for the vehicles following the leading vehicle to such an extent that autonomous driving is possible for the vehicles following the leading vehicle. The drivers of the following motor vehicles therefore no longer have to independently monitor the traffic conditions during the convoy.

Such a loosely or electronically coupled vehicle column comprises at least a first leading and a last motor vehicle and possibly medium-sized motor vehicles. It is known to have motor vehicles electronically coupled, longitudinally and transversely controlled, as close together as possible. The respective following motor vehicle is based, for example, optically on the motor vehicle driving ahead. The motor vehicles are also equipped, for example, with sensors for blind spot and rear area monitoring and for lane orientation and with means at least for vehicle-to-vehicle communication. Such loosely coupled vehicle groups or vehicle columns of motor vehicles are generally referred to as “platoons” in the literature.

When driving in close convoys during journeys from approx. 80 km / h, the air resistance of the convoy vehicles can be reduced by up to 30%. Distances in the range of 8 m to 20 m between the motor vehicle in front and the motor vehicle behind it are typically favorable in order to achieve a significant reduction in air resistance. The smaller the distances between the motor vehicles involved, the smaller the air resistance of the individual motor vehicles. In order to significantly reduce the air resistance, higher demands are placed on the driver assistance systems for automatic distance maintenance due to the small distances.

• - Einhalten eines kurzen Längsabstands der beteiligten Fahrzeuge untereinander (z.B. 8m - 20m) mit einer definierten Toleranz.
• - Automatische Querführung der Folgefahrzeuge möglichst exakt in der Spur des Führungsfahrzeugs.
• - Sicherstellen der Stabilität der Fahrzeugkolonne, d.h. insbesondere Vermeiden des „Ziehharmonika-Effekts“ (Kettenstabilität - string stability), der nicht nur zu einem erhöhten Verbrauch führt, sondern auch die Gefahr von Auffahrunfällen signifikant erhöht. Die Kettenstabilität ist dabei für Längs- und Querführung einzuhalten.
• - Kleine Änderungen in der Geschwindigkeit der vorausfahrenden Kraftfahrzeuge der Fahrzeugkolonne dürfen nicht von den nachfolgenden Kraftfahrzeugen verstärkt ausgeführt werden.
• - Für die Führung in Querrichtung darf es bei den nachfolgenden Kraftfahrzeugen nicht zu einem Schneiden von Kurven und damit zu einem Verlassen der Fahrspur kommen.
• - Ausreichend schnelle Bremsreaktion der Folgefahrzeuge bei starkem Bremsen des Führungsfahrzeugs zur Vermeidung von Auffahrunfällen.

Among other things, the following requirements are placed on the control and regulation of a convoy of vehicles:

• - Maintaining a short longitudinal distance between the vehicles involved (e.g. 8m - 20m) with a defined tolerance.
• - Automatic lateral guidance of the following vehicles as precisely as possible in the lane of the lead vehicle.
• - Ensuring the stability of the vehicle column, ie in particular avoiding the “accordion effect” (chain stability - string stability), which not only leads to increased consumption, but also significantly increases the risk of rear-end collisions. The chain stability must be maintained for longitudinal and transverse guidance.
• - Small changes in the speed of the vehicles in front of the vehicle convoy must not be increased by the vehicles behind.
• - For the guidance in the transverse direction, the following motor vehicles must not cut curves and thus leave the lane.
• - Sufficiently rapid braking reaction of the following vehicles when the lead vehicle brakes heavily to avoid rear-end collisions.

The different technical equipment and properties of the vehicles involved in the convoy, such as Engine power, performance of the permanent or service brake, vehicle configuration, load condition and tire properties, compliance with the above requirements is often difficult.

If, for example, the performance of the service brake of a motor vehicle is lower than the performance of the service brake of the motor vehicle immediately ahead, then it can be useful to automatically increase the longitudinal distance between these motor vehicles in the convoy.

In contrast, the present invention is based on the object of further developing a method of the type described above in such a way that security is increased.

This object is achieved by the features of claim 1.

Disclosure of the invention

The invention presents a method in which the longitudinal distance between motor vehicles driving one behind the other, namely an ego motor vehicle and a motor vehicle immediately ahead of it, is dependent on the performance of the service brake of the ego Motor vehicle is dynamically adapted, with at least the preceding motor vehicle being a member of an electronically coupled vehicle convoy, in which the motor vehicles of the vehicle convoy are moved along a route based on a predeterminable overall operating strategy (convoy controller) assigned to the vehicle convoy.

As part of the overall operating strategy, the first leading motor vehicle can, for example, automatically initiate a braking process, for example by means of an actuation of a brake actuator by the driver and / or by an autopilot device of the first leading motor vehicle, depending on the captured environment data, for example if the driver or the autopilot device suddenly encounter an obstacle such as a motor vehicle cutting in in front of the first leading vehicle or a stationary obstacle is detected and therefore an emergency braking of the first leading vehicle and, as a result, a braking of the entire vehicle convoy is necessary.

In the method, a characteristic curve or a map is first stored in the ego motor vehicle, which curve of target decelerations or target braking to be achieved by the ego motor vehicle as a function of various braking requirements for the service brake of the ego motor vehicle maps. In this case, a target deceleration can be equated with a target braking. For example, the relationship between the brake pressure of the service brake and the deceleration or braking is shown functionally in the characteristic diagram or in the characteristic curve. This relationship or this characteristic diagram then exists in a curve in which a specific target deceleration or target braking is assigned to each brake request or each brake pressure.

Instead of a characteristic curve or curve, a band can also be specified which defines the target deceleration or target decelerations to be achieved as a function of braking requirements. The characteristic curve, the characteristic field or the band then define a target braking deceleration capacity of the ego motor vehicle as a function of braking requirements. The braking requirements can be represented, for example, by braking pressures or by deflections (travel, angle) of a service brake actuator.

• Es wird der Längsabstand zwischen dem Ego-Kraftfahrzeug und dem diesem unmittelbar vorausfahrenden Kraftfahrzeug erfasst. Die Erfassung des Längsabstands in Bezug zu Hindernissen wie einem unmittelbar vorausfahrenden Kraftfahrzeug findet beispielsweise bei dem Ego-Kraftfahrzeug vorzugsweise ohnehin ständig statt.

Then at least the following acquisition and verification steps are carried out as part of the procedure:

• The longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it is recorded. The detection of the longitudinal distance in relation to obstacles such as a motor vehicle immediately ahead, for example, preferably takes place continuously anyway in the ego motor vehicle.

At the same time, before or after the detection of the longitudinal distance, a check is carried out to determine whether braking carried out by means of the service brake has been triggered in the ego motor vehicle, and if this is the case, a delay check is used to check whether the amount is the actual -Delay or actual deceleration of the ego motor vehicle during this braking is greater than or equal to or less than the amount of a target deceleration or a target deceleration which the ego motor vehicle would have to achieve according to the stored characteristic curve or the stored map, if it is braked with the braking request that is present during braking.

Deceleration, which is understood here as longitudinal deceleration, is defined in the mathematical sense as a negative longitudinal acceleration, an increase or increase in the longitudinal deceleration means that the amount of deceleration increases, for example from -5m / s ² to -6m / s ² . The same then also applies, conversely, to a decrease or reduction in the longitudinal deceleration, the amount of the deceleration then decreasing, for example from -6m / s ² to -5m / s ² . Instead of the amounts of the decelerations or decelerations, the absolute and then negative values of the decelerations or decelerations (negative accelerations) can therefore also be compared directly with one another.

Then the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it is adapted as a function of a result of the deceleration check.

In other words, an expected or absolutely to be achieved braking capacity of the service brake of the ego motor vehicle is defined in the form of the characteristic curve or the characteristic field, this braking capacity of the ego motor vehicle then forming a predetermined standard for at least one braking of the ego motor vehicle, which takes place, for example, as the ego motor vehicle approaches the last motor vehicle in the row of the vehicle convoy. This last motor vehicle in the row of the vehicle column then forms the motor vehicle immediately ahead of the ego motor vehicle. As an alternative to this, the braking capacity of the ego motor vehicle can also form the yardstick for at least one braking of the ego motor vehicle which carries out this when it has already been electronically coupled into the vehicle convoy.

Consequently, the braking capacity or braking deceleration capacity achieved during the last braking of the ego motor vehicle with the service brake is used in order to compare it with the specified standard in the form of the characteristic curve or the characteristic field. This has the advantage that the current state of the ego motor vehicle and in particular of its service brakes is used and not older data about it, for example, which cannot reliably map the current state.

If the ego motor vehicle then reaches or even exceeds the specified standard with regard to the braking capacity or braking deceleration capacity during the at least one braking operation, it can be provided, for example, that the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it is reduced to a nominal longitudinal distance which represents, for example, a minimum nominal longitudinal distance within the vehicle convoy. In this case, the ego motor vehicle can benefit from the advantages mentioned above, e.g. low fuel consumption when the longitudinal distance is as small as possible.

Otherwise, i.e. If the ego motor vehicle does not reach or falls below the specified standard in terms of braking performance, for example, the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead can be maintained or increased to a longitudinal distance which is greater than the minimum nominal longitudinal distance. This is because in this case it is assumed that the braking capacity of the service brake is not great enough for the ego motor vehicle to be able to drive below the minimum target distance behind the motor vehicle immediately ahead without any major risk of collision.

Also, on the basis of information about the current, i.e. braking performance of the ego motor vehicle that crystallized out during the last braking, which is sent, for example, by means of a query to the vehicle convoy, a decision is made as to whether the vehicle convoy, in response to an affiliation request signal sent by the ego motor vehicle to the vehicle convoy, the vehicle convoy with an acceptance signal or a rejection signal responds.

The method can, however, also be used in an analogous manner for a state in which the ego motor vehicle has already been electronically coupled into the vehicle column and is then already a member of the vehicle column, with the longitudinal distance between the ego motor vehicle and the latter then also being used immediately preceding motor vehicle is dynamically adapted according to the standards described above.

Dynamic adaptation of the longitudinal distance should be understood to mean that the adaptation of the longitudinal distance (initially) takes place on the basis of the most recently performed braking, which then forms the assessment basis for the deceleration check.

After at least one further braking, however, the assessment basis can change, for example in that the at least one further braking removes a layer of corrosion on the brake discs of a friction brake of the ego motor vehicle and the coefficient of friction between the brake discs and brake pads of the friction brake then increases. As a result, the braking performance or braking deceleration of the ego motor vehicle then also turns out to be higher. Then the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it could be reduced. On the other hand, repeated braking can also lead to greater wear of the service brakes of the ego motor vehicle, which in turn weakens the braking performance or braking deceleration capacity of the ego motor vehicle.

The service brake can comprise a friction brake and optionally also a permanent brake (retarder).

The features specified in the subclaims allow improvements and further developments of the method claimed in claim 1.

According to a measure to be particularly preferred, the acquisition and checking steps described above are cyclically run through several times in succession. As already described above, this may have improved or worsened the braking performance of the service brake of the ego motor vehicle. The longitudinal distance is then adapted as a function of the braking performance of the ego motor vehicle that was determined during the most recent braking. Otherwise it can also be determined in this way whether the braking deceleration capacity of the ego motor vehicle has deteriorated or improved in the course of several braking operations.

According to a further development, a constant time interval or a time-varying interval can be provided between several cycles.

According to a development of the method, the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it can be controlled or regulated by influencing the service brake and / or the engine of the ego motor vehicle and / or the motor vehicle immediately ahead.

The longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead can also be controlled or regulated by control or regulating routines which are on board the ego motor vehicle and / or on board a participant in the vehicle convoy.

In particular, the braking triggered in the ego motor vehicle can be braking triggered automatically by a driver assistance system, for example by an ACC system (Adaptive Cruise Control System) or by an emergency braking assistant of the ego motor vehicle, or by the driver of the Ego motor vehicle triggered braking, or a test braking which is triggered in the ego motor vehicle by the driver or automatically if, for example, no more braking has taken place in the ego motor vehicle within a predetermined period of time. The braking can also have been triggered by a vehicle dynamics control such as ESP (Electronic Stability System) or ROSP (Roll Over Protection System), in such a way that the vehicle dynamics control automatically intervenes in the driving dynamics of the ego motor vehicle.

In particular, the braking triggered in the ego motor vehicle can be partial braking, in which the deceleration of the service brake is less than a maximum deceleration of the service brake in the event of full braking.

The braking of the ego motor vehicle is particularly preferably carried out exclusively with a friction brake of the service brake of the ego motor vehicle, the performance of which is time-dependent due to the above-mentioned factors (removal of corrosion layers, brake wear, etc.). In this case, the characteristic curve or map which maps a course of target decelerations to be achieved by the ego motor vehicle as a function of various braking requirements for the service brake of the ego motor vehicle can relate exclusively to the friction brake, so that the benchmark is identical.

Preferably, the ego motor vehicle and the motor vehicles of the vehicle convoy exchange signals and data with each other by means of C2C communication, for example with regard to a coupling of the ego motor vehicle to the vehicle convoy and / or with regard to the dynamic adjustment of the longitudinal distance between the ego Motor vehicle and the motor vehicle immediately ahead of it.

In particular, the recording and checking steps of the method are carried out if the ego motor vehicle has not yet been electronically coupled to the vehicle convoy, but has generated an affiliation request signal, which signals that the ego motor vehicle would like to electronically couple to the vehicle convoy, or if the ego motor vehicle has already been electronically coupled with the vehicle convoy.

The vehicle convoy can comprise a first leading motor vehicle and at least one second motor vehicle following the first leading motor vehicle electronically coupled, as well as a last motor vehicle in the row, which then forms, for example, the motor vehicle immediately ahead of the ego motor vehicle when the ego motor vehicle approaches from behind the vehicle column approaches, in particular for the purpose of electronic coupling into the vehicle column.

In the stored characteristic curve or in the stored characteristic field, which maps the course of target decelerations or target brakes to be achieved by the ego motor vehicle as a function of various braking requirements for the service brake of the ego motor vehicle, the target values to be achieved Delays or target decelerations represent, in particular, delays such as are achieved under at least one predetermined operating condition. The at least one predetermined operating condition in particular represents an optimal or ideal operating condition under which a maximum target deceleration or a maximum target braking of the ego motor vehicle can be achieved.

For example, the at least one predetermined operating condition can be formed by one of the following operating conditions: a coefficient of friction between the wheels of the ego motor vehicle and a road surface, a coefficient of friction between brake disks of a friction brake of the ego motor vehicle and brake linings of the friction brake, a load condition of the ego motor vehicle, a Ambient temperature of the ego motor vehicle, a driving speed of the ego motor vehicle, etc. An operating condition is therefore to be understood as any condition which has an influence on the deceleration or braking of the ego motor vehicle.

In particular, the characteristic curve or map, which maps a course of target decelerations to be achieved by the ego motor vehicle depending on various braking requirements for the service brake of the ego motor vehicle, is used before the ego motor vehicle is first used in public road traffic Ego motor vehicle stored, so for example in the end-of-line state of the ego motor vehicle.

In particular, the service brake of the ego motor vehicle contains a pneumatic or an electro-pneumatic service brake or is formed by such. Then the braking requirements for the service brake of the ego motor vehicle are represented by pneumatic brake pressures of the service brake.

According to a further measure, the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead of it can be controlled or regulated by control or regulating routines which are on board the ego motor vehicle and / or are on board a member of the vehicle convoy.

As part of the overall operating strategy, a nominal longitudinal distance can be specified, which should or should be maintained between motor vehicles of the electronically coupled vehicle convoy driving directly one behind the other, if the motor vehicles of the electronically coupled vehicle convoy on the basis of the predefinable overall operating strategy assigned to the electronically coupled vehicle convoy along the route be moved.

If it is then assumed that the (last) braking will be triggered at a trigger time, and if the delay check then determines that the amount of the actual deceleration of the ego motor vehicle is greater than or equal to the amount of the target deceleration or the target deceleration which the ego motor vehicle should achieve according to the stored characteristic curve or the stored characteristic map when it is braked with the braking request present during braking, then the longitudinal distance between the ego motor vehicle and the vehicle at the time of triggering becomes Motor vehicle immediately ahead controlled or regulated to the nominal longitudinal distance. If, however, it is determined during the delay check that the amount of the actual deceleration of the ego motor vehicle is smaller in relation to the amount of the target deceleration or the target braking that the ego motor vehicle can achieve according to the stored characteristic curve or the stored map Should, when it is braked with the braking request present during braking, then the longitudinal distance between the ego motor vehicle and the motor vehicle immediately ahead driving it is maintained or increased, for example, at the time of triggering.

Consequently, the setpoint deceleration or setpoint braking to be achieved or achieved by the ego motor vehicle is determined with the aid of the map or the characteristic curve, which precisely corresponds to the braking request present during braking, for example the brake pressure prevailing during braking. This is easily possible due to the functional relationship between the target deceleration or the target braking and the braking request in the characteristic curve or in the characteristic map.

Figure list

• 1 eine schematische Seitenansicht einer Fahrzeugkolonne aus miteinander elektronisch gekoppelten Kraftfahrzeugen, welcher sich ein Ego-Kraftfahrzeug anschließen möchte;
• 2 eine schematische Draufsicht der Fahrzeugkolonne und das Ego-Kraftfahrzeug von 1;
• 3 ein Diagramm, in welchem der funktionale Zusammenhang zwischen Bremsanforderungen und der Verzögerung bzw. Abbremsung des Ego-Kraftfahrzeugs dargestellt ist;
• 4 ein Ablaufdiagramm einer bevorzugten Ausführungsform des erfindungsgemäßen Verfahrens.

Exemplary embodiments of the invention are shown in the drawing and explained in more detail in the description below. In the drawing shows

• 1 a schematic side view of a vehicle convoy of motor vehicles electronically coupled to one another, which would like to join an ego motor vehicle;
• 2 a schematic plan view of the column of vehicles and the ego motor vehicle of FIG 1 ;
• 3 a diagram in which the functional relationship between braking requirements and the deceleration or braking of the ego motor vehicle is shown;
• 4th a flow chart of a preferred embodiment of the method according to the invention.

Description of the exemplary embodiments

In 1 shows a schematic side view of a motorcade 1 (Platoon) of vehicles loosely or electronically coupled to one another. The vehicle column 1 includes a lead vehicle 2 as the first or foremost leading vehicle and other motor vehicles, here for example a second motor vehicle 4th , a third motor vehicle 6th , a fourth motor vehicle 8th and a fifth motor vehicle 10 . Instead of the five vehicles shown, the vehicle convoy 1 also include more or fewer motor vehicles. 2 represents the top view of the vehicle convoy 1 represents how it drives along a left curve of a route traveled by the vehicle column. The five motor vehicles 2 to 10 then each put one participant in the vehicle convoy 1 It is assumed here that the formation of the Motorcade 1 , ie the communication of the motor vehicles 2 to 10 among each other about the fact that they all form a loosely coupled vehicle column 1 is to be formed is completed.

In the exemplary embodiment, it is the motor vehicles 2 to 10 heavy commercial vehicles each with an electrically controllable drive machine, for example designed as an internal combustion engine, an electrically controllable electro-pneumatic service brake device, an electrically controllable electro-pneumatic parking brake device and an electrically controllable steering direction.

The motor vehicles or participants 2 to 10 the motorcade 1 can exchange data via on-board vehicle-to-vehicle communication equipment (C2C communication). In the present case, these are wireless vehicle-to-vehicle communication devices in which each of the motor vehicles 2 to 12 is each equipped with a transmitter and a receiver. Alternatively, the vehicle-to-vehicle communication devices can also be designed as laser or infrared transmitting and receiving devices. In 2 Vehicle-to-vehicle communication C2C taking place on the basis of the vehicle-to-vehicle communication devices is indicated by an arrow 14th symbolizes.

In addition, a wireless infrastructure-to-vehicle communication device can also be provided, for example in each of the motor vehicles or subscribers 2 to 12 is installed and also includes a transmitting device and a receiving device. So that each of the motor vehicles 2 to 12 and especially the lead vehicle 2 with an external, mobile or stationary infrastructure X communicate using an infrastructure-to-vehicle communication X2V.

As part of an overall operating strategy (column controller) of the vehicle column that is comprised by the electronic coupling 1 becomes a longitudinal distance d of the motor vehicles 2 to 10 d to a certain reference value _{is to} regulates, which here for example, 8 meters. This setpoint value d _soll represents here in particular a minimum distance which is related to the speed of the vehicle column 1 and other factors such as the performance of the brakes of your participants, the environmental data, etc. can be safely adhered to. It is assumed here that the participants in the vehicle convoy all have brakes whose performance is _{intended to} justify the distance d. Then the motor vehicles can 4th to 10 the lead vehicle 2 each by the distance d _should follow spaced from each other. Corresponding sensor devices are in the motor vehicles for this purpose 2 to 10 installed, which, for example, generate distance and speed data that are exchanged via vehicle-to-vehicle communication (C2C) 14. In addition, each of the motor vehicles is 2 to 10 equipped with an electronic control unit in which the control and regulation routines of the overall operating strategy (column controller) are implemented.

Per motor vehicle 2 to 10 Therefore, at least one transmitting device and one receiving device of the vehicle-to-vehicle communication device, a sensor device, an electronic control unit and at least one electrically controllable drive machine, an electrically controllable service brake device and an electrically controllable steering direction are available as actuators.

On the basis of the distance and speed data, which are each received by an electronic control device, an automatic electrical actuation of the electrical steering devices, the electro-pneumatic braking devices and the electrically controllable drive machines then each find their way into the vehicle convoy 1 integrated motor vehicle 2 to 12 by electrical control signals instead of one by the lead vehicle 2 predetermined target trajectory, here for example along a right lane 16 a street 18th to be followed equally spaced (see 2 ).

Furthermore, at least the lead vehicle is 2 here, for example, equipped with an autopilot device which allows the lead vehicle 2 can be operated autonomously without the driver having to do anything. The lead vehicle brakes on the basis of this autopilot device 2 for example, automatically when an obstacle, for example in the form of an external motor vehicle, is located in its driving trajectory in a manner that is critical for safety or gets into it.

At the motorcade 1 therefore become the motor vehicles 2 to 10 based on one of the vehicle convoy 1 assigned, specifiable or specified overall operating strategy is moved at least temporarily at a specifiable, constant longitudinal distance d from one another along the route.

In particular, longitudinal regulation of the motor vehicles is intended here under the overall operating strategy 2 to 10 the motorcade 1 calculated from the acceleration, speed and / or distance measurement data of the individual motor vehicles 2 to 12 the motorcade 1 to be understood from which then set values for a drive machine and / or for a braking device of the individual motor vehicles 2 to 12 the motorcade 1 to be determined. By intervening in the braking systems and / or the engines of the motor vehicles 2 to 10 longitudinal guide interventions can then take place. The overall strategy here also includes, for example, lateral guidance or lateral control of the motor vehicles 2 to 10 the motorcade 1 if, for example, the motorcade 1 to change the lane to follow the target trajectory. Automatic interventions in the electrical steering devices of the motor vehicles then also take place 2 to 12 the motorcade 1 .

The overall operating strategy therefore includes longitudinal regulation and here, for example, lateral regulation of the motor vehicles 2 , 4th , 6th , 8th , 10 the motorcade 1 calculated from the acceleration, speed and / or distance measurement data of the individual motor vehicles 2 , 4th , 6th , 8th , 10 the motorcade 1 , from which control values for a drive machine and / or for a braking device and / or for a steering device of the individual motor vehicles 2 , 4th , 6th , 8th , 10 the motorcade 1 to be determined.

As part of the overall operating strategy, the first leading motor vehicle 2 for example a braking process, for example by means of an actuation of a brake actuator by the driver and / or by an autopilot device of the first leading motor vehicle 2 automatically initiate depending on the captured environment data, for example if the driver or the autopilot device suddenly encounter an obstacle such as a vehicle in front of the first leading vehicle 2 A cutting-in motor vehicle or a stationary obstacle is detected and therefore an emergency braking of the first leading motor vehicle 2 and as a result, braking of the entire column of vehicles 1 necessary is.

There is also an external infrastructure here, for example X available which information and data, for example via an X2C communication 20 in the motor vehicles 2 , 4th , 6th , 8th , 10 and 12 the motorcade 1 and especially in the first leading motor vehicle 2 controls, which then sends this information, signals and data to the other vehicles via C2C communication 4th , 6th , 8th , 10 forwards or the information and data are then transmitted from vehicle to vehicle via the C2C communication. Alternatively, from the external infrastructure X originating information and data via the X2C communication 20 also only in the first leading motor vehicle 2 controlled, evaluated there and then, depending on the evaluation, generated signals from the first leading motor vehicle 2 can be further transmitted from vehicle to vehicle by means of C2C communication.

In terms of infrastructure X It is, for example, a road traffic authority, which data and information about the current and future weather and environmental conditions such as rain, moisture, fog, black ice in the area of the road 18th collects and then to the motorcade 1 sends. The sending of the data and information can be done at a request by the vehicle convoy 1 , especially at the request of the first leading motor vehicle 2 or automatically and especially continuously. The one from the infrastructure X The transmitted information and data then also provide environmental data in relation to the vehicle convoy 1 as a function of which, for example, the overall operating strategy of the vehicle convoy 1 is determined.

To those of the infrastructure X The transmitted information and data also include, for example, information and data about the road topology of the road on or to be driven on by the vehicle convoy 18th . This road topology includes, for example, the presence of road sections with (large) gradients, road sections with (large) gradients, and road sections with very small curve radii of the road on or to be traveled by the vehicle convoy 18th and / or whether there are constrictions, construction sites and / or entrances and exits on the road 18th are located, that is, road parameters that require driving on the road 18th through the convoy of vehicles 1 impair or hinder or even make impossible.

The convoy is in the in 1 and 2 shown situation in motion. This convoy of vehicles in motion 1 or the fifth and last vehicle 10 the motorcade 1 an ego motor vehicle is now approaching from behind 12 on, ie on the fifth or last motor vehicle 10 the motorcade 1 .

The ego motor vehicle 12 is equipped to deal with the motorcade 1 can electronically couple and then within the vehicle convoy 1 can be controlled and regulated according to the overall operating strategy. In particular, the ego motor vehicle has a sensor system with which it is a distance d in relation to obstacles, here in relation to the motor vehicle immediately ahead, fifth or last motor vehicle 10 the motorcade 1 can capture. In addition, the ego has a motor vehicle 12 also via a sensor system, which the longitudinal deceleration of the ego motor vehicle 12 can capture.

Last but not least, it also has a transmitting device and a receiving device of a vehicle-to-vehicle communication device (C2C), through which it communicates with other vehicles and in particular with the motor vehicles 2 , 4th , 6th , 8th and 10 the vehicle convoy can communicate. This communication includes, among other things, information about the currently existing longitudinal distance d to the fifth or last motor vehicle 10 the motorcade 1 , on the relative speed in relation to this and on its longitudinal deceleration a _is . Furthermore, the ego motor vehicle 12 an electro-pneumatic service brake with pneumatic service brake cylinders, which are loaded with a pneumatic brake pressure for applying and relieved for releasing.

The ego motor vehicle 12 is not yet with the motorcade 1 electronically coupled and therefore generates, for example, an affiliation request signal, which signals that the ego motor vehicle 12 to the convoy of vehicles 1 would like to electronically couple at the rear. This affiliation request signal can now from the vehicle convoy 1 be accepted or rejected.

Against this background, a preferred embodiment of a method is presented below, with which the longitudinal distance d of the ego motor vehicle 12 from the fifth and last vehicle 10 the motorcade 1 is adjusted automatically and dynamically. A flow chart for this embodiment of the method is shown in FIG 4th shown.

In the ego motor vehicle 12 or in a memory of an electronic control unit of the ego motor vehicle 12 is in one step 100 a characteristic in particular according to 3 stored which has a course of by the ego motor vehicle 12 ideally to be achieved target decelerations Z _soll or target decelerations a _soll as a function of different brake pressures (braking requirements) for the service brake of the ego motor vehicle 12 maps. This characteristic curve, which runs linearly here, assigns a specific deceleration a _soll or target braking Z _soll to each brake pressure p as a braking request, which the ego motor vehicle should achieve when a respective brake pressure p is generated by the service brake. For different load states of the ego motor vehicle, different courses of the characteristic curve are also preferably stored, the signal representing the load being generated, for example, by a pneumatic air suspension device of the ego motor vehicle and then the corresponding load-dependent setpoint for deceleration or braking is determined using the characteristic curve in question.

The following steps of the method are acquisition and checking steps, which are preferably carried out when the affiliation request signal of the ego motor vehicle 12 from the motorcade 1 has been accepted, ie has been confirmed by a positive confirmation signal, but the ego motor vehicle 12 not yet (completely) with the vehicle convoy 1 has been paired.

In one step 200 becomes the longitudinal distance d between the ego motor vehicle 12 and the fifth and final vehicle 10 the motorcade 1 detected.

In one step 300 it is checked whether in the ego motor vehicle 12 braking, in particular partial braking with the service brake, was triggered or not. During the approach of the ego vehicle 12 to the fifth and last vehicle 10 the motorcade 1 for example, the driver of the ego vehicle solves it 12 at a trigger time to, a partial braking is initiated in order to collapse the ego motor vehicle 12 on the fifth and last vehicle 10 the motorcade 1 to avoid.

If there is no braking in the ego motor vehicle 12 while approaching the convoy 1 triggered and this has also been determined, then the step 200 looped back and the longitudinal distance d again recorded. The driver of the ego motor vehicle 12 can then, for example, the distance d last taken from the fifth and last vehicle 10 the motorcade 1 of, for example, 25 meters initially maintained until there is an acceptance signal or rejection signal from the vehicle convoy 1 receives. Because in this case there is no information about the current braking deceleration capacity of the ego motor vehicle 12 in front.

But if, as in the present case, braking in the ego motor vehicle 12 triggered and this also in the crotch 300 was determined then in one step 400 checked on the basis of a delay check whether the amount of the actual delay a _{is of} the ego motor vehicle 12 with this braking is smaller than the amount of a target deceleration a _soll or a target braking Z _soll , which is the ego motor vehicle 12 according to the characteristic of 3 would achieve if it is braked p _braking with the present in this braking braking request.

If it is found at this delay, checking that the amount is the actual deceleration a _is the first-motor vehicle is greater than or equal to in relation to the amount of the target deceleration _to a, then in a step 500 the longitudinal distance d between the ego motor vehicle and the fifth and last vehicle at the time of triggering to (initially still) 10 the motorcade 1 to the nominal longitudinal distance d _{is to be} controlled or regulated, which the participants in the vehicle convoy are to maintain among themselves within the framework of the overall operating strategy.

But if at the delay check in step 400 it is established that the amount of the actual deceleration a _{is of} the ego motor vehicle 12 is smaller than the amount of the target deceleration a _soll , then in one step 600 the longitudinal distance d between the ego motor vehicle (initially still) present at the trigger time to 12 and the fifth and final vehicle 10 the motorcade 1 , which here, for example, was already greater than the nominal longitudinal distance d _soll , is increased.

The adaptation of the longitudinal distance d between the ego motor vehicle 12 and the fifth and final vehicle 10 the motorcade 1 takes place here, for example, by influencing a drive machine and / or the service brake of the ego motor vehicle 12 .

After the steps 500 and 600 becomes a step 200 looped back so that the sequence of steps 200 to 500 or. 600 for example, cyclically several times in succession, a constant time interval or a time-varying interval being able to be provided between each cycle.

With the method described above, the longitudinal distance d between the ego motor vehicle is consequently determined 12 and the fifth and final vehicle 10 the motorcade 1 depending on the braking deceleration capacity of the ego motor vehicle that emerged as part of the last braking performed 12 dynamically adjusted or controlled or regulated.

If there is no braking in the ego motor vehicle within a predefined period of time 12 has been triggered, it can be provided that braking is then automatically triggered, based on the current braking deceleration capacity of the ego motor vehicle 12 can be assessed. Such an automatically triggered braking or the braking to be evaluated is preferably a partial braking with an amount of deceleration which is smaller than an amount of deceleration as it is generated in the context of emergency braking.

In particular following the step 500 , at which the relatively small distance d _{soll is} set or regulated, a test braking can be automatically triggered after a predetermined time interval, for example, in relation to the previous braking. For example, the previous braking can also be a test braking.

List of reference symbols

1

Motorcade

2

Lead vehicle, first vehicle

4th

second motor vehicle

6

third motor vehicle

8th

fourth motor vehicle

10

fifth motor vehicle

12

Ego motor vehicle

14th

Vehicle-to-vehicle communication

16

lane

18th

road

20th

Infrastructure-to-vehicle communication

X

external infrastructure

Claims (18)

Method in which a) the longitudinal distance (d) between motor vehicles driving one behind the other, namely an ego motor vehicle (12) and a motor vehicle immediately ahead of it, is dynamically adapted depending on the performance of the service brake of the ego motor vehicle (12), at least that The preceding motor vehicle (10) is a member of an electronically coupled vehicle convoy (1), in which the motor vehicles (2, 4, 6, 8, 10) of the vehicle convoy (1) based on a predeterminable overall operating strategy (convoy controller) assigned to the vehicle convoy (1) ) are moved along a route, and b) in the ego motor vehicle (12) first a characteristic curve or a map is stored, which or which a course of target decelerations to be achieved by the ego motor vehicle (12) (a _should ) as a function of various braking requirements (p) for the service brake of the ego motor vehicle (12), the V experience further comprises at least the following detection and checking steps: c) The longitudinal distance (d) between the ego motor vehicle (12) and the motor vehicle (10) immediately ahead of it is detected, and d) it is checked whether a the service brake has been triggered in the ego motor vehicle (12), and if this is the case, then e) a delay check is used to check whether the amount of the actual deceleration (a _ist ) of the ego motor vehicle (12) greater at this braking or is equal to or smaller in relation to the amount of a target deceleration (a _soll ) which the ego motor vehicle (12) would have to achieve according to the stored characteristic curve or the stored characteristic field if it was with the braking request (pbrems) present during braking is braked, and then f) the longitudinal distance (d) between the ego motor vehicle and the motor vehicle (10) immediately ahead of it is adapted as a function of a result of the deceleration check. Procedure according to Claim 1 , characterized in that the acquisition and verification steps are cycled through several times in succession. Procedure according to Claim 2 , characterized in that a constant time interval or a time-varying interval is provided between several cycles. Method according to one of the preceding claims, characterized in that the longitudinal distance (d) between the ego motor vehicle (12) and the motor vehicle (10) immediately ahead of it by influencing the service brake and / or the engine of the ego motor vehicle (12) and / or the motor vehicle (10) immediately ahead of it is controlled or regulated. Method according to one of the preceding claims, characterized in that the braking triggered in the ego motor vehicle (12) is a) braking that is triggered automatically by a driver assistance system (ACC) of the ego motor vehicle (12), or b) braking is triggered by the driver of the ego motor vehicle (12), or c) is a test braking which is triggered automatically or by the driver in the ego motor vehicle (12). Method according to one of the preceding claims, characterized in that the braking triggered in the ego motor vehicle (12) is partial braking in which the braking effect of the service brake is less than a maximum possible braking effect of the service brake in the event of an emergency stop. Method according to one of the preceding claims, characterized in that the braking of the ego motor vehicle is carried out exclusively with a friction brake of the service brake of the ego motor vehicle (12). Method according to one of the preceding claims, characterized in that the ego motor vehicle (12) and the motor vehicles (2, 4, 6, 8, 10) of the vehicle convoy (1) exchange signals and data with one another by means of C2C communication. Procedure according to Claim 8 , characterized in that the detection and checking steps are carried out if a) the ego motor vehicle (12) has not yet been electronically coupled to the vehicle convoy (1), but has already generated an affiliation request signal which signals that the ego - wants to electronically couple the motor vehicle (12) with the convoy (1), or if b) the ego motor vehicle (12) has already been electronically coupled to the convoy (1). Method according to one of the preceding claims, characterized in that the vehicle column (1) comprises a first leading motor vehicle (2) and at least one second motor vehicle (4, 6, 8, 10, 12) following the first leading motor vehicle (2) electronically coupled . Method according to one of the preceding claims, characterized in that in the stored characteristic curve or in the stored map, which or which the course of target decelerations (a _soll ) to be achieved by the ego motor vehicle (12) as a function of different braking requirements for the service brake of the ego vehicle (12) maps, the target to be reached delays (a _soll) representing delays, as obtained under at least one predetermined operating condition. Procedure according to Claim 11 , characterized in that the at least one predetermined operating condition is formed by one of the following operating conditions: a coefficient of friction between the wheels of the ego motor vehicle (12) and a road surface, a coefficient of friction between brake disks of a friction brake of the ego motor vehicle (12) and brake linings of the friction brake , a load condition of the ego motor vehicle (12), an ambient temperature of the ego motor vehicle (12), a driving speed of the ego motor vehicle (12). Method according to one of the preceding claims, characterized in that the characteristic curve or the characteristic field, which or which a course of target decelerations (a _soll ) to be achieved by the ego motor vehicle (12) as a function of different braking requirements for the service brake of the ego -Motor vehicle (12) is stored in the ego motor vehicle (12) before the ego motor vehicle (12) is used for the first time in public road traffic. Method according to one of the preceding claims, characterized in that the service brake of the ego motor vehicle (12) contains a pneumatic or an electro-pneumatic service brake. Procedure according to Claim 14 , characterized in that the braking requirements for the service brake of the ego motor vehicle (12) are represented by pneumatic braking pressures of the service brake. Method according to one of the preceding claims, characterized in that the longitudinal distance (d) between the ego motor vehicle (12) and the motor vehicle (10) immediately ahead of it is controlled or regulated by control or regulating routines which are a) on board the Ego motor vehicle (12) are located, and / or b) are on board a participant in the vehicle convoy (1). Method according to one of the preceding claims, characterized in that a nominal longitudinal distance (d _soll ) is specified as part of the overall operating strategy, which is determined between motor vehicles (2, 4, 6, 8, 10) of the electronically coupled vehicle convoy (1 ) should be complied with when the motor vehicles (2, 4, 6, 8, 10) of the electronically coupled vehicle convoy (1) are moved along the route based on the predeterminable overall operating strategy assigned to the electronically coupled vehicle convoy (1). Procedure according to Claim 17 , characterized in that a trigger time (to) of the braking is determined, and a) if it is determined in the delay check that the amount of the actual deceleration (a _ist ) of the ego motor vehicle is greater than or equal to the amount of the target -Delay (a _soll ), which the ego motor vehicle should achieve according to the stored characteristic curve or the stored characteristic map, if it is braked with the braking request present during braking, then the longitudinal distance (d) between the ego motor vehicle and the motor vehicle (10) immediately ahead of it to the nominal longitudinal distance (d _soll ) controlled or regulated, and b) if, however, the delay check determines that the amount of the actual delay (a _ist ) of the ego -Motor vehicle (12) is smaller in relation to the amount of target deceleration (a _soll ), which the ego motor vehicle according to the stored characteristic curve or the down If it is braked with the braking request present during braking, then the longitudinal distance (d) between the ego motor vehicle (12) and the motor vehicle (10) immediately ahead at the time of triggering (to) is increased.

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