DE102016217996A1 - Method and device for determining a damage state of a component of a vehicle - Google Patents

Abstract

Method for determining a mechanical damage state (RU) of a component (30) of a vehicle (1), in which the mechanical damage state is determined as a function of at least one wheel speed of the vehicle (1).

Description

The invention relates to a method for determining a mechanical damage state of a component of a vehicle, a method for determining a threshold value for use in these methods and a computer program and a control and / or regulating device for performing one of the methods and a machine-readable storage medium on which Computer program is stored.

State of the art

In the DE 10 2014 211 896 A1 a method for monitoring a vehicle control is described. Correction values are determined by means of a correction function. The course of the correction values is recorded and extrapolated. Based on the extrapolated correction values, an error is predicted.

From the DE 42 15 938 A1 is a misfire detection system in an internal combustion engine in a motor vehicle known in which system wheel speed fluctuations of at least one wheel of the motor vehicle are measured and from these a Radunruhewert is formed; it is examined whether the Radunruhewert exceeds a threshold; and misfire detection is disabled when the wheel disturbance value exceeds the threshold.

Advantages of the invention

The method with the features of independent claim 1 has the advantage that with simple sensory means, which are present anyway in any motor vehicle, an effective damage detection of components can be done.

Advantageous developments are the subject of the dependent claims.

Disclosure of the invention

In a first aspect, the invention relates to a method for determining a mechanical damage state of a component of a vehicle, in which the mechanical damage state is determined as a function of at least one wheel speed of the vehicle. In this case, the mechanical damage condition may in particular be damage due to mechanical wear as a result of shaking stress.

Advantageously, in the determination of the mechanical damage state, the determination of a Radunruhewerts, as he from the DE 42 15 938 A1 from another context is known to be used.

This means that the mechanical damage state is determined as a function of at least three tooth times T1, T2, T3 (hereinafter "first tooth time", "second tooth time" and "third tooth time") of a tachometer wheel. Tachometer wheels usually have teeth and a tooth gap. Advantageously, the tooth times T1, T2, T3 denote the lengths of the time periods between the detection of successive teeth. Preferably, tooth times in an angular range of the tachometer wheel in which no tooth space is located are used for the evaluation.

In an advantageous development, the mechanical damage state is determined as a function of the term ((T2-T1) - (T3-T2)). In particular, it is expedient to determine the mechanical damage state as a function of a wheel disturbance value RU, which is defined as RU = ((T2-T3) - (T3-T2)) / f (Ti, Tj, Tk)

Where Ti, Tj and Tk are each selected from the set {T1, T2, T3}. Examples of f are f = T1 or f = T1 * T2 * T3.

Advantageously, it is further possible that an increment Δ of the mechanical damage state is determined as a function of the wheel disturbance value RU, and the damage state is increased by this increment Δ.

In a further aspect of the invention it can be provided that when an actual failure of the component is detected, this failure of the component is transmitted to a server together with the determined mechanical damage condition. This opens up the possibility of evaluating the mechanical damage state on the basis of a comparison with actual failures within a vehicle fleet.

In a further aspect, it can be provided that, depending on a ratio of the mechanical damage state to a determined threshold, a decision is made as to whether the mechanical damage state is critical. This makes it possible in a particularly simple way to compare e.g. with real measurement data and makes the process so very accurate.

This can in particular be done by dividing a time profile of the ratio into a first range and a second range, wherein the time profile in the first range is approximately constant and increases approximately linearly in the second range, and depending on a linear extrapolation of the time course, a time is determined at which a failure of the component is expected.

As a result, the temporal course of the relationship assumes this characteristic course. This makes it possible in a particularly simple manner to reliably predict the failure of a component, and makes it possible, for example, to inform the driver of the vehicle at an early stage and / or to automatically make contact with a spare parts provider and to reorder the soon to be dropped component.

In yet another aspect, it may be provided that the vehicle is operated in a mild mode of operation in the event of critical damage, i. that actuators in the vehicle are controlled depending on whether it has been decided that the mechanical damage condition is critical and / or controlled depending on the determined time.

In a further aspect it can be provided that for determining the threshold value for use in one of these methods, the threshold value is determined as a function of received damage states which were received together with failure messages of these components in vehicles. This allows a special accurate calibration of the process.

In a further development, it can be provided that the threshold value is determined equal to the lowest received damage state for which a failure message of this component was received in vehicles.

Hereinafter, embodiments of the invention will be explained in more detail with reference to the accompanying drawings. In the drawing show:

1 schematically a vehicle in which the method can be used;

2 a diagram showing the flowchart of the method according to an embodiment.

3 schematically a profile of the increment as a function of Radunruhewerts;

4 schematically a diagram illustrating the course of Radunruhewerts;

5 a course of the quotient as a function of mileage of a vehicle.

1 schematically shows a vehicle 1 in which the method can be used. The vehicle includes a component 30 whose mechanical damage condition is to be determined. At the component 30 For example, it may be a component of a suspension (not shown) of the vehicle 1 act, such as a ball joint, a jack, a damper or a spring.

The vehicle 1 includes a control and / or regulating device 70 on, for example, an engine control unit that may be configured to perform the method. For example, the method may be implemented by means of a computer program which is stored on a machine-readable storage medium 71 is stored, the part of the control and / or regulating device 70 is.

In the usual way, a speed sensor determines 20 with the help of a sensor element 21 , For example, a Hall encoder, tooth times of a sensor wheel 22 , for example, on an axis (not shown) of the motor vehicle 1 is mounted.

2 shows schematically the procedure of the method. Shown is the procedure for running in the vehicle 1 , Indicated are other vehicles 2 . 3 in which the method can also be used.

First, in step 1000 a speed of the speed sensor 20 receive. This is done for example by the transmission of tooth times, which, for example, rising edges on the encoder wheel 21 be identified. The durations of the time intervals between two consecutive edges are referred to as tooth times T1, T2, T3.

It follows step 1010 , in which the Radunruhewert RU from the tooth times T1, T2, T3 is determined. A typical course of Radunruhewerts RU over the time t is in 4 shown (solid line), as well as a simultaneous course of a speed v (dashed line) of the vehicle 1 , At times t1 and t2 the vehicle passes over 1 Unevenness, which is reflected in peaks of Radunruhewerts RU. At time t3, a bad distance starts at which the wheel noise value RU increases abruptly, and the speed of the vehicle 1 drops, because the driver brakes. At time t4, the bad distance ends, and the Radunruhewert RU drops from its consistently high level again on fluctuations around a low level.

After step 1010 follow step 1020 in which the corresponding increment Δ is determined as a function of the wheel disturbance value RU. This can for example be a in 3 take an illustrated course and be stored in a map that in the machine-readable storage medium 71 is deposited. It is possible that the determination of the Increments Δ not only dependent on the Radunruhewert RU is determined, but also by other factors such as a temperature or a tire pressure, the in step 1019 eg be determined with dedicated sensors.

After step 1030 follow step 1030 in which the mechanical damage condition is determined. Preferably during assembly or at a first start of the vehicle 1 the damage state is initialized to the value "0". In addition, the current mechanical damage state is increased by the respectively currently determined increment Δ (for example, at predetermined time intervals). Of course, it is also possible for only an increment Δ to be added to the state of damage if it exceeds a predefinable minimum value.

In the following step 1040 optionally a communication with a server takes place 10 , For example, in step 1040 to determine if the component 30 has failed. If this is the case, the server will 10 that transmits the component 30 has failed. Likewise, the value of the determined mechanical damage state at the time of failure of the component 30 transmitted.

In the following step 1050 receives the controller 70 from the server 10 a determined threshold. Furthermore, a quotient Q of the current determined mechanical damage state divided by the threshold value is determined. Subsequently, depending on the quotient Q, a residual life span Δs of the component 30 determined.

5 illustrates the course of the quotient Q (dotted lines) over a distance traveled s of the vehicle 1 , The distance s is here over the entire life of the vehicle 1 accumulated distance, so a total mileage of the vehicle 1 ,

5 illustrates the characteristic course of the quotient Q, which occupies approximately a constant course in a first range A at a distance traveled s smaller than a boundary point s0, and from this limit point in a second area B an approximately linearly rising course (shown in full). By means of a mathematical fitting method, for example a least square fit, s0 can be determined, and thus also the extrapolated profile in the second region B. The remaining life span Δs can then be determined as the distance which lies between the current path distance and the distance in which the linear extrapolation (drawn in dotted lines) intersects a quotient threshold Q0.

After step 1050 follow step 1060 in which it is determined whether the residual life span Δs is smaller than a predefinable residual life threshold threshold value. If this is the case, the vehicle can 1 henceforth be operated in a particularly gentle operating mode and / or a warning to the driver and / or a spare part for the component 30 be ordered.

This ends the procedure in the vehicle 1 or it starts again.

In the server 10 will be in step 1100 determines the threshold. The server receives this 10 from the vehicles 1 . 2 . 3 Feedback on what is the damage value of the component 30 in each of the vehicles 1 . 2 . 3 is installed, has failed. Depending on these failure damage values, the threshold value is determined. For example, the threshold is determined to be the smallest value at which in one of the vehicles 1 . 2 . 3 the component 30 failed due to mechanical stress.

In the optional step 1110 are optional arithmetic steps that in the embodiment in one of the steps 1020 to 1050 were listed on the server 10 carried out. Finally, the determined threshold is applied to the vehicle 1 transmitted.

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 102014211896 A1 [0002]
• DE 4215938 A1 [0003, 0007]

Claims (13)

Method for determining a mechanical damage state (RU) of a component ( 30 ) of a vehicle ( 1 ), in which the mechanical damage condition depends on at least one wheel speed of the vehicle ( 1 ) is determined. Method according to Claim 1, in which the mechanical damage state is dependent on at least three tooth times (T1, T2, T3) of a tachometer wheel ( 22 ) is determined. Method according to claim 2, wherein the mechanical damage state is determined as a function of a first tooth time (T1), a second tooth time (T2) and a third tooth time (T3), the mechanical damage state being dependent on the term ((T2-T1) - ( T3 - T2)) is determined. Method according to one of the preceding claims, wherein dependent on the at least one wheel speed Radunruhewert (RU) is determined, and depending on the Radunruhewert (RU) an increment (.DELTA.) Of the mechanical damage state is determined, and the mechanical damage state by this increment ( ) is increased. Method according to one of the preceding claims, wherein if a failure of the component ( 30 ), this failure of the component ( 30 ) together with the determined mechanical damage state to a server ( 10 ) is transmitted. Method according to one of the preceding claims, wherein, depending on a ratio (Q of the mechanical damage state to a determined threshold, it is decided whether the mechanical damage state is critical. Method according to claim 6, wherein a profile of the ratio (Q) is subdivided into a first region (A) and a second region (B), the profile being approximately constant in the first region (A) and approximately in the second region (B) increases linearly, and depending on a linear extrapolation of the course, a residual life span (Δs) is determined, after which a failure of the component ( 30 ) is expected. Method according to claim 6 or 7, wherein actuators in the vehicle ( 1 ) depending on whether it has been decided that the mechanical damage state is critical and / or controlled as a function of the determined residual life span (Δs). Method for determining a threshold value for use in the method according to one of claims 6 to 8, wherein the threshold value is determined as a function of received mechanical damage states which together with failure messages of these components ( 30 ) of vehicles ( 1 . 2 . 3 ) were received. Method according to claim 9, wherein the threshold value is determined equal to the lowest received mechanical damage condition, to which a failure message of this component ( 30 ) of a vehicle ( 1 . 2 . 3 ) was received. Computer program adapted to carry out the method according to one of Claims 1 to 10. Machine-readable storage medium ( 71 ) on which the computer program according to claim 11 is stored. Control and / or regulating device ( 70 ) arranged to carry out the method according to one of claims 1 to 10.

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