Sensor Self-Diagnosis via Signal Integration

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Solution Overview

Problem

Existing self-diagnostic methods for acceleration and angular-velocity sensors often produce incorrect results due to external impacts during the diagnosis process, as they rely on signal levels that differ when a pseudo signal is applied versus when it is not, leading to unreliable sensor status determination.

Innovation Solution

A self-diagnostic device comprising a diagnosis control unit, an integration unit, and a determination unit that applies a test signal to the sensor, integrates the sensor signal, and determines the sensor's status based on the integration value within a prescribed normal range, effectively suppressing the impact's effect during the diagnosis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pseudo signal is applied to the sensor element for self-diagnosis, then the sensor output signal level changes enabling diagnosis, but external impacts during diagnosis cause incorrect diagnostic results

Engineering Contradiction:

Improveself-diagnosis accuracyVSAvoidexternal impact effect

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts only the essential diagnostic information by integrating the sensor output signal over a predetermined time period. This integration process filters out transient external impact effects while retaining the meaningful diagnostic signal response, thereby separating the useful diagnostic data from harmful noise.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent performs preliminary integration of the sensor output signal before making the diagnostic determination. By accumulating the signal over time in advance of the final judgment, the system prepares a stabilized diagnostic value that is less susceptible to momentary external disturbances.

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If signal level comparison is performed for self-diagnosis, then diagnostic determination can be made, but the diagnosis is unreliable when external acceleration or angular velocity is inputted

Engineering Contradiction:

Improvediagnosis determinationVSAvoiddiagnosis accuracy under external input

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent maintains continuous integration of the sensor output signal over a predetermined time period rather than making instantaneous comparisons. This continuous accumulation of signal information ensures that the diagnostic determination is based on a sustained pattern rather than momentary fluctuations caused by external inputs.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent changes the diagnostic parameter from instantaneous signal level comparison to integrated signal value over time. By transforming the diagnostic criterion from a point-in-time measurement to a time-accumulated value, the system achieves more reliable diagnosis that is insensitive to transient external accelerations or angular velocities.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8423229B2Device and method for performing self-diagnosis as to whether or not acceleration or angular-velocity sensor is in normal status

Publication Date: 2013.04.16 MITSUBISHI ELECTRIC CORP

AI summary

A self-diagnostic device for an acceleration or angular-velocity sensor includes a diagnosis control unit, an integration unit, and a determination unit. The diagnosis control unit provides pseudo acceleration or angular velocity to a sensor main body for detecting acceleration or angular velocity, by applying a test signal having prescribed magnitude to the sensor main body. The integration unit integrates a sensor signal outputted from the sensor main body in response to the test signal. The determination unit determines whether or not an integration value obtained at an elapse of prescribed integration time from a time point when the integration unit starts integrating the sensor signal falls within a prescribed normal range.