Method, computer program, electronic storage medium and apparatus for monitoring a sensor system

Abstract

The invention relates to a method (100) for monitoring a sensor system, wherein the sensor system comprises at least three sensors, wherein the at least three sensors detect the same measured variable, the method comprising the following steps: detecting (101) sensor signals of the at least three sensors; determining (102) a minimum value and a maximum value of the detected sensor signals; identifying (103) a faulty sensor depending on a ratio among the determined ratios.

Description

Technical Field

[0001] This invention relates to a method, computer program, electronic storage medium, and apparatus for monitoring sensor systems. Background Technology

[0002] The concept of surveillance has long been known in industry, with various applications, such as in nuclear power plants or aircraft. In many applications, humans act as both observers and decision-makers. These systems have also been generally described in the literature.

[0003] For example, “Fault-Diagnostic Systems: An Introduction from Fault Detection” by Isermann, R. (2010), published in Springer London. Summary of the Invention

[0004] Against this backdrop, the present invention proposes a method for monitoring a sensor system, wherein the sensor system includes at least three sensors, wherein the at least three sensors detect the same measurement variable. The method includes the following steps:

[0005] Detect sensor signals from at least three sensors;

[0006] Determine the minimum and maximum values ​​of the detected sensor signal;

[0007] The faulty sensor is identified based on the ratio of the determined ratio.

[0008] This invention can be used to monitor sensor systems with at least three sensors. It can be easily extended to systems with more than three sensors.

[0009] According to the present invention, the monitored sensor system comprises at least three sensors that detect the same measured variable. These sensors can be constructed identically. However, this is not absolutely necessary for the present invention.

[0010] Importantly, these sensors detect the same measurement variables, and the differences in the detected measurement variables are primarily attributed to sensor-specific tolerances.

[0011] This invention is based on the understanding that in a sensor system with at least three sensors, the sensor signal for the detected measurement variable must be found within limits set by the specific tolerances of each sensor. A deviation occurs when one of the at least three sensors malfunctions. If all detected sensor signals are within the set limits, then all sensors are functioning correctly.

[0012] According to one embodiment of the method according to the invention, in the identification step, if the determined ratio exceeds a predetermined threshold, the detected sensor signals are compared in pairs, wherein the pairwise comparison is performed according to the predetermined threshold.

[0013] According to this embodiment, the monitoring method of the present invention is divided into two stages. In the first stage, the ratio between the minimum and maximum values ​​of the currently detected sensor signal is determined. This ratio is essentially defined by the tolerances of at least three sensors in the monitored sensor system.

[0014] If the ratio exceeds a predetermined threshold for the ratio between the detected minimum and the detected maximum, the method proceeds to the second stage.

[0015] In the second stage, pairwise comparisons of the detected sensor signals are performed.

[0016] With three sensors, three scenarios are possible, each involving one sensor signal falling outside a predetermined threshold of the sensor tolerance. With more than three sensors, even more scenarios may occur. Therefore, more pairwise comparisons are required.

[0017] Another aspect of the present invention is a computer program configured to perform all the steps of the method according to the invention.

[0018] Another aspect of the present invention is an electronic storage medium on which a computer program according to the present invention is stored.

[0019] Another aspect of the invention is an apparatus for monitoring a sensor system comprising at least three sensors. Here, the at least three sensors detect the same measurement variable. Here, the apparatus is configured to perform all the steps of the method according to the invention. Attached Figure Description

[0020] The embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings.

[0021] Figure 1 A flowchart illustrating one embodiment of the method of the present invention is shown. Detailed Implementation

[0022] Figure 1 A flowchart of one embodiment of the method 100 of the present invention is shown.

[0023] In step 101, sensor signals from at least three sensors of the sensor system are detected. Important for this invention is that at least three sensors detect the same measured variable. Here, the three sensors do not necessarily have to be identical. Here, at least three sensors provide at least three sensor signals for the detected measured variable. Assuming that the sensor signals of these sensors deviate from each other only within sensor-specific tolerances, the sensor signals can then be evaluated for monitoring the sensor system, and more specifically, for identifying faulty sensors.

[0024] In step 102, the minimum and maximum values ​​of the detected sensor signals are first determined, and then set as a ratio relative to each other. Effective methods for determining the minimum and maximum values ​​are known to those skilled in the art and are not central to this invention. The ratio relative to each other can be determined by division. Thus, the determined ratio represents a measure of the difference in the sensor signals.

[0025] In step 103, faulty sensors are identified based on the determined ratio. For this purpose, the determined ratio can be compared to a predetermined tolerance threshold for the ratio. The tolerance threshold can be predetermined by considering both sensor-specific tolerances and the accuracy requirements of the subsequently detected measurement variable or sensor signal.

[0026] If the determined ratio and the difference in the sensor signal are outside the tolerance limits, thus exceeding the tolerance threshold, it indicates that the sensor is faulty.

[0027] Then, within the scope of step 103 for identifying faulty sensors, a pairwise comparison of the detected sensor signals can be performed to identify sensor signals that are outside a predetermined tolerance limit, thereby identifying faulty sensors.

[0028] The method of this invention can be implemented using software or hardware. A possible implementation, presented in pseudocode, is given below, which reproduces both the determination of the ratio and the pairwise comparison of sensor signals.

[0029] THD: = 10%; / / (Sensor tolerance, 10% is exemplary here)

[0030] Sensor_variation:=1-min(|a|,|b|,|c|) / max(|a|,|b|,|c|);

[0031] If (Sensor_variation ≤ THD)

[0032] {return Sensoren-OK; / / All sensors are within the predetermined tolerance limits}

[0033] }

[0034] Else

[0035] / / Perform pairwise comparisons by querying the predetermined tolerance limits

[0036] Case_a:((1-min(|a|,|b|) / max(|a|,|b|)>THD)|(1-min(|a|,|c|) / max(|a|,|c|)>THD))&(1-min(|b|,|c|) / max(|b|,|c|)≤THD); / / Sensor a is outside the sensor limit

[0037] Case_b:((1-min(|a|,|b|) / max(|a|,|b|)>THD)|(1-min(|b|,|c|) / max(|b|,|c|)>THD))&(1-min(|a|,|c|) / max(|a|,|c|)≤THD); / / Sensor b is outside the sensor limit

[0038] Case_c:((1-min(|b|,|c|) / max(|b|,|c|)>THD)|(1-min(|a|,|c|) / max(|a|,|c|)>THD))&(1-min(|a|,|b|) / max(|a|,|b|)≤THD); / / Sensor c is outside the sensor limit

[0039] }

Claims

1. A method (100) for monitoring a sensor system, wherein the sensor system comprises at least three sensors, wherein the at least three sensors detect the same measured variable, the method comprising the steps of: detecting (101) sensor signals of the at least three sensors; determining (102) a ratio of a minimum value and a maximum value of the detected sensor signals; identifying (103) a fault in the at least three sensors in dependence on a deviation of the determined ratio from 1 exceeding a predetermined threshold value; comparing the detected sensor signals with each other pairwise only if a fault in the at least three sensors is identified, to identify a faulty sensor of the at least three sensors.

2. An electronic storage medium, on which a computer program is stored, the computer program being configured to perform all steps of the method (100) according to claim 1.

3. An apparatus for monitoring a sensor system, the sensor system comprising at least three sensors, wherein the at least three sensors detect the same measured variable, the apparatus being configured to perform all steps of the method (100) according to claim 1. ​ ​ ​ ​

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