WO2020049073A1

WO2020049073A1 - Method and system for exchanging coefficient of friction data for vehicles

Info

Publication number: WO2020049073A1
Application number: PCT/EP2019/073634
Authority: WO
Inventors: Gerrit SCHMITZ
Original assignee: Robert Bosch Gmbh
Priority date: 2018-09-06
Filing date: 2019-09-05
Publication date: 2020-03-12
Also published as: DE102018215170A1

Abstract

The invention relates to a method for exchanging coefficient of friction data. The method makes possible a more precise application of coefficients of friction and comprises the following steps: - providing a coefficient of friction (μ) for a road surface section (160, 170) by means of a database (120), to which database the at least one first vehicle (140) and one second vehicle (150) have access, wherein data for determining the coefficient of friction (μ) is determined at least partially on the vehicle side and made available to the database (120), - assigning a first coefficient of friction correction factor (k1) to the first vehicle (140) and a second coefficient of friction correction factor (k2) to the second vehicle (150), wherein each of the coefficient of friction correction factors (k1, k2) is determined at least partially on the vehicle side. The invention further relates to a system (100) suitable for performing the method.

Description

description

Title:

Method and system for exchanging friction data for vehicles

The present invention relates to a method and a system for exchanging friction data of a traffic area section. The invention can be used advantageously, in particular, for vehicles that travel on such a traffic area section.

State of the art

The coefficient of friction between a vehicle, in particular its tire, and a traffic area section, such as a roadway, influences the dynamic driving limits of a vehicle with regard to longitudinal and transverse guidance. In a conventional vehicle driven by a human driver, the driver may e.g. Using empirical values, brief braking, visual perception or the like, at least to some extent, determine whether the current coefficient of friction is rather high or rather low. For example, the current coefficient of friction on a well-developed and clean road surface and when it is dry can be rather high and thus promote good static friction between the vehicle and the road surface, whereas wetness, black ice,

Contamination of the road or the like can adversely affect the coefficient of friction.

In the case of partially or fully autonomous ferry operation of a vehicle

Estimating the current coefficient of friction of a traffic area section is more difficult since the information of the human vehicle driver is at least partially lost. In order to counter this problem, WO 2016/120092 A1, for example, proposes a database-supported coefficient of friction map in which information sent by sending vehicles is received and stored in the database, the information describing at least the specific coefficient of friction potential of a road segment Friction data include the location data describing the geometric position of this road segment and the time data describing the time of determination of the friction data and the data stored in the database can be called up by receiving vehicles. Although this gives the vehicle helpful information on the current coefficient of friction of a vehicle

Can be made available, there is a desire to be able to provide a vehicle with even more precise coefficient of friction data.

Disclosure of the invention

Embodiments of the invention provide an improved possibility for exchanging friction data of traffic areas.

A proposed method for exchanging friction data can e.g. be carried out with a database and / or server-based system that exchanges the coefficient of friction data via e.g. a data network enables. The process has the following steps:

- There is a coefficient of friction of a traffic area section by a

Database provided, at least a first vehicle and a second vehicle having access to the database. The data to determine the coefficient of friction are at least partially

determined by the vehicle and made available to the database. The data can be exchanged between the database and the vehicles, for example, via a data network.

- In addition, a first coefficient of friction correction factor is assigned to the first vehicle and a second coefficient of friction correction factor to the second vehicle, the respective coefficient of friction correction being determined at least in part by the vehicle.

In this context, the coefficient of friction correction can be understood as a measure which specifies which dynamic driving values the vehicle under consideration can achieve in comparison to a number of other vehicles. For example, in a lot of vehicles with mixed vehicle types, sports vehicles may have higher ones Coefficients of friction have as the average, for example by

Vehicle construction, such as the chassis design, or other tire compounds, etc. can come about. If, however, a fleet of vehicles of the same type is considered, which therefore only consists of such sports car types, the same vehicle could have a different coefficient of friction correction. The assignment of the coefficient of friction correction can be done for example via a data network, the coefficient of friction correction together with the coefficient of friction through the database, i.e. e.g. linked to the coefficient of friction as a data set, can be provided. The first and second vehicles can e.g. have access to the database via a mobile data connection. The vehicle can be a

Be a motor vehicle that can also be suitable for a semi-autonomous or fully autonomous ferry operation.

This method makes it possible to provide a more precise, in particular more plausible, coefficient of friction for a traffic area section by not only weather data, e.g. from a rain sensor of the vehicle or one

Weather data service, but also other vehicle-related influencing factors can also be taken into account. So at the vehicle side

Determination, for example, of the condition of the tires, their mix, age tread depth etc. can also be taken into account. In principle, the coefficient of friction correction can thus establish a clearer relationship between the coefficient of friction and a particular vehicle.

A further development provides that the respective coefficient of friction correction can be made available to the database. For this a

Data connection are used, e.g. can also be configured bidirectionally, on the one hand, to determine the at least partially determined in the vehicle

To send the coefficient of friction correction to the database and on the other hand to receive the coefficient of friction and / or the possibly also adjusted coefficient of friction correction from the database in the vehicle, in particular during its operation.

According to another development, the coefficient of friction can be compared with the

Coefficient of friction correction are standardized. This enables a better comparison with other coefficients of friction. Here, for the standardized coefficient of friction (Norm) for example: \\ {Norm) = k (Fzg) _* \ x {Fzg), where k (Fzg) refers to the

Vehicle-related coefficient of friction correction and \ i (vehicle) the associated

Is coefficient of friction.

In another development, the coefficient of friction correction

be determined specific to the vehicle type. This means that it cannot only be used for a specific vehicle, e.g. can be identified by his registration number or his vehicle identification number (VIN), but instead eat or be additionally assigned to a specific vehicle type, vehicle model, a specific vehicle configuration, etc. The vehicle type can also be determined, for example, from the vehicle identification number (VIN) and / or other key numbers. This enables an even more objective assessment of the coefficient of friction, in particular the proportion thereof, which is dependent on the vehicle type.

According to a further development, a warning can be provided for the respective vehicle, e.g. as signal data or the like if the coefficient of friction related to the vehicle and corrected by the coefficient of friction correction factor deviates inadmissibly from a warning threshold. So certain can

Vehicles and / or drivers of a particular vehicle are warned even more precisely or are specifically informed about a warning or the like.

In particular, an individual warning of a vehicle is possible.

For example, for a traffic area section, there may be a danger to a vehicle due to wetness, e.g. Has tires with a shallow tread depth on one or both axles, while for another

Vehicle with a high tread depth is not an immediate danger. In this case, one vehicle can be warned in a timely manner before reaching the traffic area section, while the other vehicle can be warned accordingly. This can prevent unwanted or unnecessary warnings. For example, the following can be used to provide the warning: m (standard) <\ i (warning) _* k (vehicle), where m (standard) is the standardized coefficient of friction, \} {warning) is the warning threshold value and k (vehicle) is on the vehicle related

Are friction correction factor.

Another development provides that the coefficient of friction correction factors are compared between at least the first vehicle and the second vehicle, the deviation of the coefficient of friction correction factors from one to the other Problem of the respective vehicle is closed. In other words, the coefficient of friction correction factors can be compared with one another, ie among the vehicles, in order to identify vehicle-specific problems, such as tires with insufficient tread depth. This can be particularly true in

Fleets of a specific vehicle type are carried out, so that an outlier can be clearly identified among the coefficient of friction correction factors.

It is also possible for the database to identify abnormal states of the respective vehicle. For example, the

Friction correction factors are filtered according to a specific model and / or vehicle type and this is viewed as a distribution. The bottom x% of the vehicles can then be informed accordingly that there may be a malfunction on the vehicle side.

As mentioned above, the coefficient of friction correction can be provided or sent from the database. In further training, the

Coefficient of friction correction factor for vehicles of identical, same or at least similar type have at least one essentially identical initial value. This can e.g. the current average coefficient of friction correction factor for this vehicle type or this vehicle model or in the initial state 1. During the operation of the vehicle, with certain aging

This value can then be used on the vehicle side, e.g. be adjusted algorithmically.

Another development provides that the coefficient of friction correction factors of the vehicles can mutually influence one another. This can be particularly the case if the vehicles are in a similar or the same location at a similar or the same time. In other words, the first and second vehicles can meet at a meeting, that is to say when these are in close proximity

geographical and / or topographical and temporal limits deliver a value of the coefficient of friction correction, the respective coefficient of friction correction are re-divided. These limits can be freely defined. For example, these smaller fleets can be defined more generously, since the specific coefficient of friction correction becomes more meaningful from a certain frequency. Furthermore, positions and times can be identified at which

Traffic area sections often provide similar values - due to the same surface and weather conditions - to increase the number of meetings. At such a meeting you can

Friction correction factors of the vehicles according to the determined, e.g.

measured, friction values are redistributed. For redistribution based on mean values, for example:

The coefficient of friction correction of the vehicle can preferably increase with the higher measured coefficient of friction and decrease that of the other vehicle, since they have experienced a comparable situation. This decrease or

Increase can be linear, exponential, logarithmic, or a combination thereof.

According to another further development, at least data from a driving dynamics control system of the respective vehicle can be evaluated in order to determine the coefficient of friction correction on the vehicle. From this, e.g.

Information about the slip behavior is determined, whereby for a specific, in particular temporally and locally determined,

Traffic area section data may already be available, so that conclusions can be drawn from a slippage that is not expected per se, a worn tire or the like and, if appropriate, a comparatively lower one

Coefficient of friction correction can be derived.

The invention also relates to a system for exchanging friction data. The system can be computerized and e.g. be server-like with a data connection. The system has a database, which is set up to determine an at least partially vehicle-specific coefficient of friction for a

Traffic area section to provide at least a first vehicle and a second vehicle. The database is also set up to assign a vehicle-specific first coefficient of friction correction to the first vehicle and a vehicle-specific second coefficient of friction correction to the second vehicle. The system can be operated in one or more of the described embodiment variants using the methods explained above and thus offers the advantages explained above.

Further measures improving the invention are described in more detail below together with the description of the preferred exemplary embodiments of the invention with reference to figures.

Brief description of the figures

In the following, advantageous exemplary embodiments of the invention are described in detail with reference to the accompanying figures. Show it:

Figure 1 is a schematic overview of a system for the exchange of

Friction coefficient data between a database and a plurality of vehicles and

Figure 2 is a flow diagram of a method for exchanging

Friction coefficient data.

The figures are only schematic and are not to scale. In the figures, the same, equivalent or similar elements are provided with the same reference numerals throughout.

Embodiments of the invention

Figure 1 shows a system 100 which is suitable for the electronic exchange of friction data, e.g. using cloud computing. The system 100 has a server 110 which has a memory for program instructions, a processor for executing the program instructions, etc., a database 120 which is functionally connected to the server 100, and a communication interface 130 to a data network which in particular enables a radio connection.

Furthermore, the system 100 has two vehicles 140, 150 as examples, each of which has access to the server 110 or the database via a first data connection 141, 151, which are only indicated here by two symbols to have. In addition, the vehicles 140, 150 are in contact with one another via a second data connection 142, 152, this being indicated here only as an example as a separate data connection and, for example, centrally via the

Communication interface 130 can take place. The data connections 141,

151 or 142, 152, for example, produces a radio module that is installed in the respective vehicle 140 or 150. The data connection 141, 151 and 142, 152 is bidirectional and leaves both server side and

receiving and sending of data on the vehicle side. It should be noted that the system 100 e.g. can also be accessible by vehicle fleet, so that dozens, hundreds, thousands or even millions of vehicles can be integrated.

The first vehicle 140 travels a first traffic area section 160 and the second vehicle 150 travels a second traffic area section 170, which can be geographically far apart and which are, for example, roads with a e.g. paved road surface. The determination of the coefficient of friction data of the traffic area sections 160, 170 to be exchanged takes place at least partially on the vehicle side, for which purpose a (not specified) control unit of the vehicles 140, 150 is based on data from one

Driving dynamics control, such as an anti-lock system and an anti-slip control access.

The system 100 can operate as described below, with the server-side functions stored in the

Program instructions are included and are executed by the processor in order to also trigger activation of the communication interface 130 and the database 120.

In principle, the vehicles 140, 150 each collect data on the coefficient of friction m of the traffic area section 160, 170 they are traveling on and send this to the database 120 at a definable frequency, for example with additional information about location, time, weather conditions, etc. This processes the sent data and, if necessary, supplements them with further information, such as other weather data. In addition, the data collected by vehicles 140, 150 can be checked for plausibility among themselves. The data collected in the database 120 are available to all vehicles 140, 150 and are either in the form of map data from a navigation system as a data block or selectively made available as individual data for certain traffic area sections to be traveled.

In this exemplary embodiment, it is possible, for example, for the vehicle 140 to receive data on the coefficient of friction m of the road section 160 from the database 120 at time t1, which data was collected by the vehicle 150 at a time tO while driving on the road section 160.

Conversely, at time t2, vehicle 150 may receive data on the coefficient of friction m of road section 170, which vehicle 140 collected at time t1.

In order to support the coefficient of friction m made available for the vehicles 140, 150, a first coefficient of friction correction factor kl is additionally determined by the first vehicle 140 and a second coefficient of friction correction factor k2 is determined by the second vehicle 150, transmitted to the database 120 and there or in the Server processed. The coefficient of friction correction factor k1, k2 is vehicle-specific and / or vehicle-type-specific and, viewed at least over a period of time, can vary from vehicle 140 to vehicle 150

differentiate. The coefficient of friction correction factor k1, k2 contains, for example, a statement about the quality of the road holding of the vehicle 140, 150 in question, etc. The database 120 thus provides a combination of the coefficient of friction m and the coefficient of friction correction k1, k2.

The database 120 or the system 100 use the

Coefficient of friction correction k1, k2 for normalizing the coefficient of friction m, so that in this exemplary embodiment the following applies: m (norm) = k (vehicle) _* m {vehicle). This enables a more precise determination of the friction values m and a more precise comparison of the friction values m, since vehicle-related influencing variables are taken into account more precisely. For example, a lower coefficient of friction m can also be negatively influenced by a comparatively poor vehicle condition, which is caused by the

additional coefficient of friction correction kl, k2 can be detected.

Furthermore, the system 100 is set up to send out a vehicle-specific warning if a warning threshold value for the respective vehicle 140, 150 is violated, taking into account the specific coefficient of friction correction kl, k2, where: m (norm) <m (1 / Karn) _* k {vehicle). In the event that the vehicles 140, 150 travel on the same traffic area section, for example the

Traffic area section 160, the system 100 is set up to initiate a mutual influencing of the coefficient of friction correction factors k1 and k2, where the following applies:

For the sake of clarity, the method described above is shown again in FIG. 2 in a flow chart. In a step S1, the coefficient of friction in the traffic area section 160, 170 is provided by the database 120 to the vehicles 140, 150. In a step S2, the first coefficient of friction correction factor k1 is assigned to the first vehicle 140 and the second coefficient of friction correction factor k2 to the second vehicle 150.

Claims

Expectations

1. Procedure for exchanging friction data, with the steps:

- Providing a coefficient of friction (m) of a traffic area section (160, 170) through a database (120) to which at least a first vehicle (140) and a second vehicle (150) have access, at least data for determining the coefficient of friction (m) partly determined on the vehicle side and made available to the database (120),

marked by

- Assigning a first coefficient of friction correction factor (kl) to the first vehicle (140) and a second coefficient of friction correction factor (k2) to the second vehicle (150), the respective

Friction coefficient factor (kl, k2) is determined at least partially on the vehicle side.

2. The method according to claim 1, characterized in that the respective coefficient of friction correction (kl, k2) is made available to the database.

3. The method according to claim 1 or 2, characterized in that the

Coefficient of friction (m) is standardized with the coefficient of friction correction (kl, k2).

4. The method according to any one of the preceding claims, characterized

characterized that the coefficient of friction correction (kl, k2)

is determined specific to the vehicle type.

5. The method according to any one of the preceding claims, characterized

characterized in that a warning is provided for the respective vehicle (140, 150) if the coefficient of friction (m) related to the vehicle (140, 150) and corrected by the coefficient of friction correction factor (kl, k2) is from a warning threshold value (p (warning) ) deviates impermissibly.

6. The method according to any one of the preceding claims, characterized

characterized that the coefficient of friction correction factors (kl, k2) between at least the first vehicle and the second vehicle are compared, a deviation of the friction correction factors (kl, k2) being used to infer a problem of the respective vehicle.

7. The method according to any one of the preceding claims, characterized

characterized in that the coefficient of friction correction factor (k) for vehicles of identical type has at least one essentially identical initial value.

8. The method according to any one of the preceding claims, characterized

characterized in that the coefficient of friction correction factors (kl, k2) of the vehicles (140, 150) mutually influence one another if the vehicles are at a similar or the same time at a similar or the same location.

9. The method according to any one of the preceding claims, characterized

characterized in that the vehicle-side determination of the

Friction correction factor (k) at least data from one

Driving dynamics control system of the respective vehicle can be evaluated.

10. System (100) for exchanging friction data, with a database (120), which is set up to have an at least partially on the vehicle side

to provide a determined coefficient of friction (m) for a traffic area section (160, 170) of at least a first vehicle (140) and a second vehicle (150),

characterized,

that the database (120) is also set up to give the first vehicle (140) a vehicle-specific first coefficient of friction correction factor (kl) and the second vehicle (150) a vehicle-specific second

Assign the coefficient of friction correction (k2).