EP1573293A2

EP1573293A2 - Method and device for fault analysis of motor vehicle control units and corresponding control unit

Info

Publication number: EP1573293A2
Application number: EP03767391A
Authority: EP
Inventors: Alexander Ketterer; Andreas LÄUFER
Original assignee: Siemens AG
Current assignee: Continental Automotive GmbH
Priority date: 2002-12-20
Filing date: 2003-10-28
Publication date: 2005-09-14
Also published as: WO2004061405A3; WO2004061405A2

Abstract

The invention relates to a method for analysis of errors in a controller (10) of a component on a motor vehicle. The controller (10) is subjected to a signalling environment on a test bed and an error recording device (16), provided in the controller (10), is read off. The invention is characterised in that during a test bed recognition step (14), test bed recognition means determine if the signalling environment is generated by a test bed and where this is the case the current state of the error recording device (16) is stored and made independently accessible. The invention further relates to a corresponding system and a controller (10).

Description

description

Method and system for fault analysis of motor vehicle control units and corresponding control unit

The invention relates to a method for analyzing errors in a control unit of a component of a motor vehicle, the control unit being exposed to a signal environment in a test bench and an error storage device provided in the control unit being read out.

The invention further relates to a system for analyzing errors in a control unit of a component of a motor vehicle, comprising the control unit and a test bench which exposes the control unit installed in it to a signal environment, an error memory device provided in the control unit being readable.

Finally, the invention relates to a control device for controlling a component of a motor vehicle as a function of a signal environment acting on the control device with a fault memory device, via which malfunctions of motor vehicle elements can be read out.

Such methods, systems and control devices are known and are often used in modern motor vehicles or in their development, maintenance and / or repair.

Modern motor vehicles form a highly complex interplay of individual components that are increasingly controlled by electrical signals and also communicate with one another via electrical signals. For this purpose, the individual components ^~ separate security elements-as airbags, hochkom- - plex populations, such as motors, or other devices can be assigned to controllers. These control units receive a large number of signals from control units of other components connected to them and control their NEN assigned component depending on this signal environment. At the same time, each control unit sends its own state-identifying signals to the other control units connected to it. In many motor vehicles, this communication takes place via a so-called CAN (Control Area Network) bus, to which all control units are connected via appropriate interfaces.

The control units usually include a fault memory device which, in the event of a malfunction, which, for. B. is recognized based on function parameters outside a predetermined value range, make a corresponding error code accessible to the user or other vehicle components. This can be done, for example, by querying the other components or by actively sending an error message. Malfunctions can e.g. B. caused by damage to the control unit, the associated vehicle component or by a faulty signal environment.

To analyze the error, the corresponding control device is usually removed, possibly together with the assigned component, and installed in a special test bench which has signal generators which expose the control device to a signal environment. The signal environment is intended to simulate the real signal environment in the assembled state. By changing the signal environment, different operating states can be simulated and the function of the control device and its fault memory device can be examined.

A disadvantage of this known method or the system used for this or the known control devices is that the signal environment simulated by the test bench often does not ^“ realistically” simulate the reality of the operating case, which leads to additional errors due to the test bench. These are difficult or even impossible indistinguishable from the actual errors. DE 198 57 462 AI discloses a method for optimizing the signal environment. It is based on the fact that the output signals of all control devices connected to the control device to be examined are measured and stored in different operating states and the signal generators of the test bench are then controlled according to the stored parameters. This approach is very effective in the development and fine-tuning of vehicle components if the basic functionality of all elements can be assumed and if, instead of the component to be set, an identical component is used in an assembled overall system to obtain the required parameters. The method fails, however, if errors of an individual component have to be analyzed, or if there is even ambiguity as to whether the actual error is in the control device being examined or in its signal environment, that is to say from other components.

It is the object of the present invention to provide a method, a system and a control device by means of which the above-mentioned problems of the prior art are overcome, in particular a better separation of actual and test bench-related errors ,

This object is achieved with the features of the independent claims. Advantageous embodiments of the present invention are specified in the dependent claims.

The invention builds on the generic method by determining in a test bench detection step by test bench detection means ^" whether the ^" signal environment is generated by a test bench and, if this is the case, the current state of the fault memory device is stored and made accessible independently. This ensures that the fault memory device in the Operating errors determined can be read out and analyzed without the errors induced by the test stand environment being misinterpreted as actual errors, which could lead to incorrect conclusions. On the contrary, it is even possible to adapt the test bench environment so that the errors determined in the test bench correspond to the stored errors, which can be used to optimize the test bench environment or to identify errors in the signal environment of the control unit in the assembled state. The test bench can be designed in a correspondingly simple manner, which leads to cost savings. Different control units that are exposed to different signal environments in the vehicle can also be analyzed on the same test bench.

Basically, there are various ways in which the test stand detection means, which can be implemented in software, for example, differentiate the test stand operation from real operation. Thus, it can be provided that the test bench identification means determine, based on a predetermined value pattern of at least some of the components of the signal environment, whether the signal environment is generated by a test bench. Global values such as e.g. B. speed, load, engine temperature, etc., but also more detailed variables such as slope or amplitude of electrical signals. This method is particularly secure against manipulation, since it requires a very precise knowledge of the test bench characteristics. On the other hand, it can make a very complex design of the test stand detection means or a standardized test stand design necessary. This is particularly due to the internal connection system sizes that are essential for the control of an engine or of components to one-ordinary loading ^'drive to ensure the case.

As an alternative, it can therefore also be provided that the test bench detection means is based on a separate, predetermined one Test bench signal determine whether the signal environment is generated by a test bench. This method is particularly easy to implement since it only requires the transmission of a standardized signal from the test bench to the control unit. However, this simplicity is susceptible to manipulation and abuse. In particular embodiments of the invention, combinations of both alternatives can therefore be implemented.

In a particularly preferred embodiment of the invention, it can be provided that the test stand detection step is preceded by a monitoring step in which a decision by the test stand detection means is checked on the basis of further criteria. This provides additional security against an alleged but inaccurate detection of test bench conditions.

The current state of the error memory device is generally stored by writing the corresponding data into memory means provided for this purpose. For this purpose, separate storage means can be provided, into which the values are transferred and recorded in addition to the further operation of the error storage device. With regard to the costs of the additional storage means, however, in a special embodiment of the invention it may be more advantageous if the storage takes place while the fault storage device is deactivated. This corresponds to “freezing” the current state. There are namely memory units anyway in the error storage means, for. B. intermediate buffer provided, the z. B. can be used to make the error data available to other elements. At a deactivation of the error memory means thus the usual continuous overwriting is this ^"storage means with updated data inhibited. At the respective outputs of the control device remain thus abut status data the desired supply. It is particularly favorable if the control device has an interface to a CAN bus. On the one hand, this enables the control device to be easily integrated into the entirety of the motor vehicle. On the other hand, data between the control unit and the test bench or other units can easily be read out and read in via such a standardized interface.

The invention is based on a generic system in that test stand detection means are provided in the control device to determine whether the signal environment is generated by a test stand and, if this is the case, the current state of the fault memory device can be stored and is independently accessible after storage. The test stand identification means can be implemented in software, for example, and only require a suitable input option, eg. B. a CAN bus for the signals to be processed.

It is preferably provided that the test bench identification means are able to determine, based on a predetermined value pattern of at least some of the components of the signal environment, whether the signal environment is generated by a test bench.

Alternatively, it can be provided that the test stand communicates a separate, predetermined test stand signal to the test stand detection means, by means of which the test stand detection means are able to determine whether the signal environment is generated by a test stand.

Of course, it is also possible to implement a suitable combination of the two aforementioned variants in one embodiment of the invention.

To optimize the system security, it can preferably be provided that the test stand detection means have superordinate monitoring means which are able to detect Divorce of the test stand detection means to be checked against other criteria. The monitoring means can also be implemented in software, for example.

In addition to the possibility of transferring this data to separate storage means for storing the status data of the error storage device, a particularly favorable embodiment of the invention provides for the current status of the error storage device to be stored while the error storage device is deactivated at the same time.

It is particularly favorable if the control unit is connected to further control units of further vehicle components in the assembled state via a CAN bus. In an advantageous development of the system according to the invention, the CAN bus interface required for this can also be carried out via this standardized interface for reading out the stored status data of the fault memory device.

The invention is based on a generic control device in that test bench detection means are provided for determining whether the signal environment is generated by a test bench and, if this is the case, the current state of the fault memory device can be stored and is independently accessible after storage.

The control device according to the invention is preferably characterized in that the test bench detection means are able to determine, on the basis of a predetermined value pattern of at least some of the components of the signal environment, whether the signal environment is generated by a test bench.

Alternatively, however, it can also be provided that the test stand detection means are able to determine, on the basis of a separate, predetermined test stand signal communicated by a test stand, whether the signal environment is test bench is generated. The test bench detection means can be implemented in software, for example.

Of course, a combination of the two aforementioned alternatives can also be implemented in a particular embodiment of the invention.

To increase the security of the control device according to the invention, it can be provided that the test stand detection means have superordinate monitoring means which are able to check a decision of the test stand detection means on the basis of further criteria. The monitoring means can also be implemented in software, for example.

In addition to the possibility of overwriting the status data of the error memory device for storage in separate memory means, in a special development of the control device according to the invention it can be provided that the current status of the error memory device is stored with simultaneous deactivation of the error memory device.

The invention will now be explained by way of example with reference to the accompanying drawing using a preferred embodiment.

It shows:

1: a block diagram of an embodiment of the method according to the invention.

1 shows, in a highly simplified and schematic form, an exemplary embodiment of ^" the ^" method according to the invention, which can run in a control device 10 according to the invention as part of the system according to the invention. The graphic is used only to illustrate the principle of the invention and does not distinguish sharply between process and device elements.

Block 12 represents the internal variables of the control unit 10, which u. a. derive from the signal environment to which the control device 10 is exposed via interfaces that are not shown in detail. These internal variables form patterns of certain parameter values. These samples are interpreted in the procedural step of test bench identification - represented by block 14 and carried out by test bench recognition means (not shown in more detail) - as characterizing the operational or test bench case. If the test stand identification shows that the test stand case and not the operating case is present, the error storage means 16 are deactivated in the following method step or, depending on the previous state, are not activated (block 18). 1 shows an exemplary embodiment in which the state parameters of the error storage means 16 are “frozen” when the test stand case is recognized. The error memory of the error memory means can then be read out via an interface (not shown in detail), preferably a standardized CAN bus interface, and interpreted by the test bench software.

In order to reliably avoid inadvertent and erroneous test stand detection during operation, in the exemplary embodiment of FIG. 1 a monitoring function 20 is superior to test stand detection 14 and deactivation 18. It preferably only allows deactivation if the decision of the test bench detection means has been judged to be correct on the basis of further criteria. In the embodiment shown, the monitoring function 20 is designed in such a comprehensive manner that it also controls the recording of the internal parameters “(Bloc 12)” and the error memory device (Block 16).

Of course, the exemplary embodiment shown merely represents an exemplary illustration of a preferred embodiment. tion form that can be modified in many ways within the scope of the present invention. In particular, instead of or in addition to deactivating the error storage means, a transfer of their current status parameters into separate storage means can be provided.

The features of the invention disclosed in the above description, in the drawings and in the claims can be essential both individually and in any combination for realizing the invention.

Claims

claims

1. A method for analyzing errors in a control unit (10) of a component of a motor vehicle, the control unit being exposed to a signal environment in a test bench and an error memory device (16) provided in the control unit being read, characterized in that in a test bench detection step ( 14) it is determined by test stand identification means whether the signal environment is generated by a test stand and, if this is the case, the current state of the fault memory device (16) is stored and made accessible independently.

2. The method according to claim 1, so that the test bench detection means (14) determine, based on a predetermined value pattern of at least some of the components of the signal environment, whether the signal environment is generated by a test bench.

3. The method as claimed in claim 1, so that the test bench detection means (14) determine on the basis of a separate, predetermined test bench signal whether the signal environment is generated by a test bench.

4. The method as claimed in one of the preceding claims, namely that a monitoring step (20) is superordinate to the test bench detection step (14), in which a decision by the test bench detection means (14) is checked on the basis of further criteria.

5. The method according to any one of the preceding claims, characterized in that the current state of the error memory device (16) is stored while the error memory device (16) is deactivated (18) at the same time.

6. The method according to any one of the preceding claims, d a d u r c h g e k e n n e e c h n e t that the control unit (10) has an interface to a CAN bus.

7. The method according to any one of the preceding claims, that the stored state of the fault memory device (16) is read out via a standardized interface.

8. The method according to claims 6 and 7, d a d u r c h g e k e n n z e i c h n e t that the standardized interface the CAN bus

Interface is.

9. System for analyzing errors in a control unit (10) of a component of a motor vehicle, comprising the control unit (10) and a test bench that exposes the control unit installed in it to a signal environment, wherein an error storage device (16) provided in the control unit (10) ) can be read out, characterized in that test stand detection means (14) are provided in the control unit (10) for determining whether the signal environment is generated by a test stand and, if this is the case, the current state of the fault memory device (16) can be stored and after Storage is accessible independently.

10. System according to claim 9, characterized in that the test bench detection means (14) are able, based on a predetermined value pattern of at least some of the Components of the signal environment determine whether the signal environment is generated by a test bench.

11. The system of claim 9, so that the test bench communicates a separate, predetermined test bench signal to the test bench detection means (14), by means of which the test bench detection means are able to determine whether the signal environment is generated by a test bench.

12. System according to one of claims 9 to 11, so that the test stand detection means (14) have superordinate monitoring means (20) that are able to check a decision of the test stand detection means (14) on the basis of further criteria.

13. System according to one of claims 9 to 12, so that the current state of the error memory device (16) is stored with simultaneous deactivation (18) of the error memory device (16).

14. System according to one of claims 9 to 13, so that the control device (10) is connected to further control devices of further vehicle components via a CAN bus in the installed state.

15. System according to one of claims 9 to 14, characterized in that the ^" stored ^" state of the error memory device (14) can be read out via a standardized interface.

16. System according to claim 15, characterized in that the standardized interface is a CAN bus interface.

17. Control device for controlling a component of a motor vehicle as a function of a signal environment acting on the control device (10) with a fault memory device (14), by means of which malfunctions of motor vehicle elements can be read out, so that test stand detection means (14) are provided

Determining whether the signal environment is generated by a test bench and, if this is the case, the current state of the fault memory device (16) can be stored and can be accessed independently after storage.

18. Control device according to claim 17, so that the test bench recognition means (14) are able to determine, based on a predetermined value pattern of at least some of the components of the signal environment, whether the signal environment is generated by a test bench.

19. Control device according to claim 17, so that the test bench detection means (14) are able to determine on the basis of a separate, predetermined test bench signal communicated by a test bench whether the signal environment is generated by a test bench.

20. Control device according to one of claims 17 to 19, characterized in that the test stand detection means (14) monitoring means (20) - are superordinate, - which are able -, - a decision of the test stand detection means (14) based on further criteria to check.

21. Control device according to one of claims 17 to 20, characterized in that the storage of the current state of the error memory device (16) takes place with simultaneous deactivation (18) of the error memory device (16).

22. Control device according to one of claims 17 to 21, that the control device (16) is connected to further control devices of further vehicle components via a CAN bus in the installed state.

23. System according to one of claims 17 to 22, so that the stored state of the fault memory device (16) can be read out via a standardized interface.

24. The system as claimed in claim 23, so that the standardized interface is a CAN bus interface.