US-12618697-B2 - Method for diagnosing a sensor system in a part-specific manner

US12618697B2US 12618697 B2US12618697 B2US 12618697B2US-12618697-B2

Abstract

A method for carrying out a diagnosis of a sensor system. The method including: (i) ascertaining a processing specification of a test signal and/or of a characteristic physical variable and/or its respective change as a function of at least one part-specific property of the sensor system; and (ii) carrying out a subsequent diagnosis of a sensor element of the sensor system, using the processing specification ascertained in (i).

Inventors

Frank Drautz
Michael Schiebold
Paolo Minotti

Assignees

ROBERT BOSCH GMBH

Dates

Publication Date: 20260505
Application Date: 20220210
Priority Date: 20210218

Claims (13)

1 . A method for carrying out a diagnosis of a sensor system, comprising the following steps: (i) ascertaining a plurality of processing specifications of test signals and/or of a characteristic physical variable and/or a respective change of a test signal and/or the characteristic physical variable, as a function of at least one part-specific property of the sensor system; and (ii) carrying out a subsequent diagnosis of a sensor element of the sensor system, using the plurality of processing specifications ascertained in (i), wherein a part-specific correlation factor is ascertained for each sensor element of the sensor system which is a function of a respective part-specific processing specification, wherein the sensor system comprises a micromechanical rotation rate sensor having a negative frequency split, the diagnosis being carried out using a part-specific correlation factor determined for the negative frequency split design.
2 . The method as recited in claim 1 , further comprising: carrying out a recalibration of the sensor element of the sensor system as a function of a result of the diagnosis.
3 . The method as recited in claim 2 , wherein the diagnosis and/or the recalibration of the sensor element is carried out at defined points in time.
4 . The method as recited in claim 1 , wherein feedback of the sensor system is provided to a user as a function of a result of the diagnosis.
5 . The method as recited in claim 1 , wherein a constant term of the processing specification takes on the following form: C 0 =CF( pp )·β where: β is a constant which is not part-specific, but is empirically ascertained based on a large number of identical sensor elements.
6 . The method as recited in claim 1 , wherein the processing specification is changed over a service life of the sensor system.
7 . A method for manufacturing a sensor system, comprising the following steps: a) ascertaining, in a part-specific manner, a mathematical relationship between a test signal and a response signal of a sensor element of the sensor system to the test signal; and b) implementing the mathematical relationship ascertained in step a) in the sensor system after a final trim of the sensor element, wherein the sensor system comprises a micromechanical rotation rate sensor having a negative frequency split, the diagnosis being carried out using a part-specific correlation factor determined for the negative frequency split design.
8 . The method as recited in claim 7 , wherein parameters of the ascertained mathematical relationship are calculated in the part-specific manner and stored in the sensor system.
9 . The method as recited in claim 7 , wherein the mathematical relationship is at least partially implemented in software and/or at least partially in hardware.
10 . The method as recited in claim 8 , wherein the mathematical relationship is stored by programming a programmable chip.
11 . The method as recited in claim 7 , wherein the mathematical relationship is changed over a service life of the sensor system.
12 . The method as recited in claim 7 , wherein the mathematical relationship for a defined sensor type encompasses an approximation according to defined physical relationships.
13 . A non-transitory computer-readable data medium on which is stored a computer program for carrying out a diagnosis of an electronic sensor system, the computer program, when executed by the electronic sensor system, causing the electronic sensor system to perform the following steps: (i) ascertaining a plurality of processing specifications of test signals and/or of a characteristic physical variable and/or a respective change of a test signal and/or the characteristic physical variable, as a function of at least one part-specific property of the sensor system; and (ii) carrying out a subsequent diagnosis of a sensor element of the sensor system, using the plurality of processing specifications ascertained in (i), wherein the sensor system comprises a micromechanical rotation rate sensor having a negative frequency split, the diagnosis being carried out using a part-specific correlation factor determined for the negative frequency split design.

Description

CROSS REFERENCE The present application claims the benefit under 35 U.S.C. § 119 of German Patent Application No. DE 10 2021 201 537.9 filed on Feb. 18, 2021, which is expressly incorporated herein by reference in its entirety. FIELD The present invention relates to a method for diagnosing a sensor system in a part-specific manner. The present invention furthermore relates to a method for manufacturing a diagnosable sensor system. The present invention furthermore relates to a computer program product. BACKGROUND INFORMATION A variety of different methods is increasingly used in conventional sensor systems for diagnosis, in particular for self-monitoring and self-calibration (self-sensing sensors). In addition to the obvious desirable requirement to also maintain the accuracy of the sensor which was achieved, e.g., with the aid of a suitable trim at the end of the manufacturing process as well during the entire operating duration, i.e., in particular, to compensate for, e.g., aging effects which occur, further applications include the exact and robust measurement under differing usage conditions (e.g., changed ambient condition such as temperature, moisture or mechanical stresses as they may arise, e.g., as a result of the installation or external vibrations) as well as self-monitoring of the sensor with respect to correct functional capability (the latter, in particular, in safety-relevant applications). A method for recalibrating a sensor with the aid of a suitable test signal is described in German Patent Application No. DE 10 2018 207 573 A1, in which, in particular, a trim correction value is calculated, a corresponding relationship either being empirically determined in advance, based on a plurality of measurements on identical sensors, or determined with the aid of further influencing variables, which may also be part-specific parameters. In some sensor systems, an identical evaluation of test signals and/or characteristic variables may lead to non-satisfactory results, in particular, when the relationship between the observed variables and the variables to be examined which is used for the diagnosis is highly dependent on further variables. One example of this is a micromechanical rotation rate sensor having separate drive and detection frequencies (so-called mode-split or also open-loop design, in contrast to mode-matching or also closed-loop design), in which the detection frequency has a smaller value than the drive frequency (so-called negative frequency split design). SUMMARY It is an object of the present invention to provide an improved method for diagnosing a sensor system. According to a first aspect of the present invention, the object may be achieved by a method for carrying out a diagnosis of a sensor system. In accordance with an example embodiment of the present invention, the method includes the following steps: (i) ascertaining a processing specification of a test signal and/or of a characteristic physical variable and/or its respective change as a function of at least one part-specific property of the sensor system; and(ii) carrying out a subsequent diagnosis of a sensor element of the sensor system, using the processing specification ascertained in (i). In this way, e.g., a change in the sensitivity of the sensor element may be established, which may be improved by a recalibration based on the diagnosis during operation. Advantageously, the described method is, in particular, usable for sensor systems having relatively large tolerances during manufacture, in which, e.g., the behavior of the test signals used is highly dependent on these tolerances. One example of this are micromechanical rotation rate sensors having a negative frequency split, the method, however, being explicitly not limited to this specific sensor type. According to a second aspect of the present invention, the object may be achieved by a method for manufacturing a sensor element of a sensor system. In accordance with an example embodiment of the present invention, the method includes the following steps: a) ascertaining, in a part-specific manner, a mathematical relationship between a test signal and a response signal of a sensor element of the sensor system to the test signal; andb) implementing the mathematical relationship ascertained in step a) in the sensor system after a final trim of the sensor element. Advantageous refinements of the method of the present invention are disclosed herein. One advantageous refinement of the method of the present invention provides that a recalibration of a sensor element of the sensor system is carried out as a function of a result of the diagnosis which was carried out. Another advantageous refinement of the method of the present invention provides that the diagnosis and/or the recalibration of the sensor element is/are carried out at defined points in time. For example, this may take place daily, weekly, monthly, etc. As an alternative, the diagnosis may be requested by t