DE102019211021B4 - Method for detecting a time offset - Google Patents

Abstract

A method for detecting a time offset between a first control device (12) and a second control device (14), the control devices (12, 14) each being connected to an identical voltage source (16), with the following steps: - Supplying (S1) the first control device (12) and the second control device (14) with voltage, which is subject to a stochastic process, by means of the voltage source (16); - digitizing (S2) the voltage; - generating (S3.1) a first stamp based on the stochastic voltage curve the digitized voltage by means of the first control device (12) and generation (S3.2) of a second stamp based on the stochastic voltage curve of the digitized voltage by means of the second control device (14); - transmission (S4) of the first stamp and / or the second stamp to an evaluation device; - comparing (S5) the first stamp with the second stamp; - determining (S6) a time offset between the first control device (12 ) and the second control device (14) when the first stamp differs from the second stamp.

Description

The present invention relates to a method for detecting a time offset between two control devices and a control device module for a vehicle with at least two control devices.

In the context of autonomous driving, it is known to control vehicles by means of at least two control devices. Furthermore, methods for detecting a time offset between two control devices or synchronization methods for control devices between which there is a wired connection are known. the end DE 10 2017 113 564 A1 describes an operating method of a communication node for detecting connection errors in a network. DE10 2017 209 328 A1 discloses a device for synchronizing clocks in control units.

Against this background, the invention is based on the object of providing a method for detecting a time offset which is independent of a wired connection between the control devices.

According to the invention, this object is achieved by a method for detecting a time offset with the features of claim 1 and / or by a control unit module for a vehicle with the features of claim 10.

• - Ein Verfahren zum Detektieren eines Zeitversatzes zwischen einem ersten Steuergerät und einem zweiten Steuergerät, wobei die Steuergeräte jeweils mit einer identischen Spannungsquelle verbunden sind, mit den folgenden Schritten: Versorgen des ersten Steuergeräts und des zweiten Steuergeräts mit Spannung, die einem stochastischen Prozess unterliegt, mittels der Spannungsquelle; Digitalisieren der Spannung; Generieren eines ersten Stempels aufgrund des stochastischen Spannungsverlaufs der digitalisierten Spannung mittels des ersten Steuergeräts und Generieren eines zweiten Stempels aufgrund des stochastischen Spannungsverlaufs der digitalisierten Spannung mittels des zweiten Steuergeräts; Übermitteln des ersten Stempels und/oder des zweiten Stempels an eine Auswerteeinrichtung; Vergleichen des ersten Stempels mit dem zweiten Stempel; Feststellen eines Zeitversatzes zwischen dem ersten Steuergerät und dem zweiten Steuergerät, wenn sich der erste Stempel von dem zweiten Stempel unterscheidet; sowie
• - Ein Steuergerätemodul für ein Fahrzeug mit einem ersten Steuergerät und einem zweiten Steuergerät, einer Spannungsquelle zum Versorgen des ersten Steuergeräts und des zweiten Steuergeräts mit Spannung, wobei das erste Steuergerät und das zweite Steuergerät eingerichtet sind, aufgrund eines stochastischen Spannungsverlaufs einen Stempel zu generieren, den Stempel an eine Auswerteeinheit zu übermitteln, und aufgrund der übermittelten Stempel einen Zeitversatz zu detektieren, wenn sich der erste Stempel von dem zweiten Stempel unterscheidet.

Accordingly, it is provided:

• - A method for detecting a time offset between a first control device and a second control device, the control devices each being connected to an identical voltage source, with the following steps: Supplying the first control device and the second control device with voltage that is subject to a stochastic process by means of the voltage source; Digitizing the voltage; Generating a first stamp on the basis of the stochastic voltage profile of the digitized voltage by means of the first control device and generating a second stamp on the basis of the stochastic voltage profile of the digitized voltage by means of the second control device; Transmitting the first stamp and / or the second stamp to an evaluation device; Comparing the first stamp with the second stamp; Determining a time offset between the first control device and the second control device if the first stamp differs from the second stamp; as
• - A control unit module for a vehicle with a first control unit and a second control unit, a voltage source for supplying the first control unit and the second control unit with voltage, wherein the first control unit and the second control unit are set up to generate a stamp based on a stochastic voltage curve, the To transmit stamp to an evaluation unit, and to detect a time offset on the basis of the transmitted stamp when the first stamp differs from the second stamp.

Vehicles within the meaning of this patent application are land vehicles, aircraft and / or watercraft.

Identical means that something is the same.

A control device is, for example, an ECU. Control devices are electronic modules that are used for control or regulation.

A voltage source is, for example, a battery.

Stochastic processes are not deterministic and are subject to a random process. For example, a noise process is subject to a stochastic process. A voltage-related value is a quantity that relates to a voltage curve. This can be, for example, a voltage value or a slope, curvature or the like of the voltage curve. The invention provides stochastic voltage curves. Properties of the stochastic process on which the voltage curve is based, such as a variance, are therefore also voltage-related values.

An evaluation unit comprises a processor with computing power. A control device can also be an evaluation unit.

A stamp is a data word that contains the properties of a voltage curve. The voltage-related data can also be stored in the stamp in coded form.

A sensor, also known as a detector, (measured variable or measuring) pick-up or (measuring) sensor, is a technical component that has certain physical, chemical properties or states, e.g. B. temperature, humidity, pressure, speed, brightness, acceleration, pH value, ionic strength, electrochemical potential and / or the material nature of its environment qualitatively or quantitatively as a measured variable. These variables are recorded using physical or chemical effects and converted as sensor data into an electrical signal that can be processed further. Vehicle sensors are mounted on a vehicle in order to detect a vehicle environment. Sensor data, that are recorded by vehicle sensors are sensor data related to the vehicle environment.

A time delay between two control units can result from the fact that the control units do not receive input data, e.g. sensor data, at the same time. A duration of a time offset is the time difference between the control units.

In this patent application, the term derivative includes a local value of a slope or a derivative function. The local value of the slope can relate to a point or to a specified interval.

In this patent application, the term mean value comprises a local mean value of a curve or a sequence of data points over a time interval or an antiderivative.

The variance is a measure of the spread of a random variable around its expected value. In this patent application, the term variance also includes so-called empirical variance. The empirical variance is a statistical indication of the range of values of a sample and, in descriptive statistics, a key figure of a sample. It is one of the measures of dispersion and describes the mean square deviation of the individual measured values from the empirical mean.

In signal analysis, the cross-correlation is used to describe the correlation of two signals x (t) and y (t) with different time shifts, i.e. a time offset, between the two signals.

Synchronization refers to the timing and ordering of processes, clocks and / or measured values. Synchronization ensures that processes run simultaneously (synchronously) or in a certain temporal order.

Computer program products generally comprise a sequence of instructions which, when the program is loaded, cause the hardware to carry out a specific method that leads to a specific result.

The underlying idea of the invention is to connect at least two control devices to an identical voltage source that is subject to a stochastic voltage curve. A stochastic voltage curve can be provided by means of a conventional vehicle battery, since the on-board network voltage of a vehicle is subject to stochastic processes due to non-deterministic effects.

In order to detect a time offset between the control devices, the invention provides for a voltage-related value that is applied to the first control device at a point in time to be compared with a voltage-related value that is applied to the second control device at that time. If the voltage-related values are identical, there is no time delay between the control units. If the voltage-related values are not identical, the method detects a time offset between the control units.

It goes without saying that one of the control devices can also guarantee the functionality of the evaluation unit. In this case it can be provided that only one control device transmits a stamp to another control device (master).

Accordingly, in one embodiment of the invention it can be provided that the first control device transmits a current voltage value as a first stamp to the second control device and the second control device checks whether the first stamp is identical to the second stamp.

In a further embodiment of the invention it can also be provided that the stamp furthermore contains data or a characteristic key for data which are processed at the point in time of the voltage value on which a respective stamp is based. This makes it possible, for example, to determine whether the right data is being processed by a control unit at the right time.

Advantageous refinements and developments emerge from the further subclaims and from the description with reference to the figures of the drawing.

According to a preferred development of the invention, the stamp has further local characteristic values of the voltage profile, in particular a derivation over at least one time interval, an average value over at least one time interval, a variance over at least one time interval and / or the like. In this way, the ambiguity of stamps with regard to points in time in the voltage curve can be reduced.

In this way, false negative process results can be reduced. False negative means that the method for detecting a time offset does not detect a time offset, although there is a time offset between two control units. This can result, for example, from the fact that a stamp at one point in time happens to be identical to another stamp at another point in time. Since the derivative, the mean and / or the variance of a stochastic process is independent of the stochastic process itself, the Reduce the likelihood that two punches will be identical at different times.

According to a preferred development of the invention, several stamps from different points in time are compared. Accordingly, it can be provided, for example, that the stamp contains a curve section of the voltage profile. In this way, the probability of false negative process results can be further reduced.

It is also expedient to determine a cross-correlation based on the multiple stamps and to measure a time offset based on the cross-correlation. In this way, the duration or length of a time offset can also be determined. This is helpful, for example, when the control units are synchronized at a later date.

According to a preferred development of the invention, the stamp also has a time information relating to the point in time at which the stamp was generated. The time is an absolute indication of the time and in particular the date.

Alternatively and / or additionally, it is advantageous if the stamp also has sensor data that was transmitted to the control device at the time at which the stamp was generated. This avoids determining a time. This can be advantageous if it is to be expected that the determination of a time is subject to inaccuracies which are relevant for the method. Accordingly, it could be provided, for example, that the stamp also has a camera image that was recorded by a vehicle camera. If the sensor data, for example the camera images, two stamps and the voltage-related values of the stamps, are identical, it can be assumed that the control units are processing identical sensor data at the same time.

According to a preferred development of the invention, the control devices are synchronized when a time offset is detected.

According to a preferred development of the invention, the duration of the time offset is quantified on the basis of a characteristic value, in particular a derivation of the voltage value in the first stamp and / or in the second stamp. It is thus possible, for example, for the difference between two stamps to allow conclusions to be drawn about the duration or length of the time delay. Since the derivative, i.e. the slope, of the voltage curve fluctuates and is independent of an absolute voltage value, the mere difference between two voltage values does not allow any conclusions to be drawn about the length or duration of a time delay.

According to a preferred development of the invention, the voltage is decoupled from a DC voltage.

It goes without saying that a control device module according to an embodiment of the invention is also advantageous for control devices that are spatially separated from one another or at a distance, since a spatial distance between control devices can be the cause of a time offset.

The computer program product according to one embodiment of the invention carries out the steps of a method according to the preceding description when the computer program product runs on a computer, in particular a computer internal to the vehicle. When the program in question is used on a computer, the computer program product produces an effect, namely to detect a time offset between two control units.

Figure list

• 1 ein schematisches Blockschaltbild einer Ausführungsform der Erfindung;
• 2 ein schematisches Blockschaltbild einer Ausführungsform der Erfindung;

The present invention is explained in more detail below with reference to the exemplary embodiments specified in the schematic figures of the drawings. It shows:

• 1 a schematic block diagram of an embodiment of the invention;
• 2 a schematic block diagram of an embodiment of the invention;

The accompanying drawings are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the advantages mentioned emerge with a view to the drawings. The elements of the drawings are not necessarily shown to scale with one another.

In the figures of the drawings, elements, features and components that are the same, functionally identical and have the same effect - unless stated otherwise - are each provided with the same reference symbols.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

1 Figure 3 shows a schematic block diagram according to an embodiment of the invention. In the step S1 becomes a first and a second control unit 12th , 14th by means of a voltage source 16 provided. In the step S2 is the voltage by means of the first and second control device 12th , 14th digitized. In the step S3 is a stamp due to the stochastic voltage curve by means of the first and second control device 12th , 14th generated. In the step S4 becomes the first punch from the first control unit 12th to the second control unit 14th , which takes over the functionality of an evaluation device, is transmitted. In the step S5 becomes the first stamp with that of the second control unit 14th generated second stamp compared. In the step S6 becomes a time offset between the first control unit 12th and the second control unit 14th detected when the first stamp differs from that of the second stamp.

2 shows a schematic block diagram according to an embodiment of a control device module 10 . The control unit module 10 comprises a first control device 12th , a second control unit 14th , which ensures the functionality of an evaluation unit, as well as a voltage source 16 who have favourited the control units 12th , 14th , supplied with voltage. Between the control units 12th , 14th there is a data connection for exchanging stamps. About a possible time delay between the control units 12th , 14th to detect, the transmitted stamps are compared.

List of reference symbols

10

Control unit module

12th

Control unit

14th

Control unit

16

Voltage source

S1-S6

Procedural steps

Claims (11)

Method for detecting a time offset between a first control device (12) and a second control device (14), the control devices (12, 14) each being connected to an identical voltage source (16), with the following steps: - Supplying (S1) the first control device (12) and the second control device (14) with voltage, which is subject to a stochastic process, by means of the voltage source (16); - digitizing (S2) the voltage; - Generating (S3.1) a first stamp based on the stochastic voltage profile of the digitized voltage by means of the first control device (12) and generating (S3.2) a second stamp based on the stochastic voltage profile of the digitized voltage by means of the second control device (14); - Transmission (S4) of the first stamp and / or the second stamp to an evaluation device; - comparing (S5) the first stamp with the second stamp; - Establishing (S6) a time offset between the first control device (12) and the second control device (14) when the first stamp differs from the second stamp. Method for detecting a time offset according to Claim 1 , the stamp having further local characteristic values of the voltage profile, in particular a derivation over at least one time interval, a mean value over at least one time interval, a variance over at least one time interval and / or the like. Method for detecting a time offset according to one of the preceding claims, wherein a plurality of stamps from different points in time are compared. Method for detecting a time offset according to Claim 3 , wherein a cross-correlation of the voltage-related data of the stamps is determined and a time offset is determined based on the cross-correlation. Method for detecting a time offset according to one of the preceding claims, wherein the stamp furthermore has a time information relating to the point in time at which the stamp was generated. Method for detecting a time offset according to one of the preceding claims, wherein the stamp furthermore has sensor data which were transmitted to the control device (12; 14) at the point in time at which the stamp was generated. Method for detecting a time offset according to one of the preceding claims, wherein the control devices (12, 14) are synchronized when a time offset is detected. Method for detecting a time offset according to one of the preceding claims, wherein the duration of the time offset is quantified on the basis of a further characteristic value, in particular a derivation of the voltage value in the first stamp and / or in the second stamp. Method for detecting a time offset according to one of the preceding claims, wherein the voltage is decoupled from a direct voltage by means of the first and / or the second control device (12; 14). Control device module (10) for a vehicle with a first control device (12) and a second control device (14), a voltage source (16) for supplying the first control device (12) and the second control device (14) with voltage, wherein the first control device (12) and the second control device (14) are set up to generate a stamp based on a stochastic voltage curve, to transmit the stamp to an evaluation unit, and to apply a time offset based on the transmitted stamp detect when the first stamp differs from the second stamp. Computer program product which is designed to be loaded into a memory of a computer and which comprises software code sections with which the steps of the method according to one of the preceding Claims 1 - 9 be executed when the computer program product is running on the computer.

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