Physical Quantity Detection Circuit Abnormality Diagnosis
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Solution Overview
Problem
Existing capacitance-based physical quantity detection apparatuses face challenges in diagnosing abnormalities, particularly when the apparatus is in motion, as existing self-diagnosis mechanisms may not function correctly during manufacturing defects or in-use failures, leading to inaccurate data processing.
Innovation Solution
A physical quantity detection circuit that includes a signal generation circuit, an abnormality determination circuit, and a diagnostic circuit, which analyzes the value and change in the physical quantity signal to determine potential abnormalities, allowing for real-time diagnosis even when the apparatus is in motion by setting threshold values for signal values and changes, and using test signals to confirm abnormalities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-diagnosis mechanism is provided in the physical quantity detection element itself, then abnormality detection capability is improved, but element area increases and manufacturing complexity increases
Solution Approach 1:
The self-diagnosis function is extracted from the physical quantity detection element itself and implemented as a separate abnormality determination circuit that processes output signals. This separation allows the detection element to remain simple while the diagnosis capability is provided by an independent circuit module that analyzes signal characteristics without requiring additional space within the element structure.
Solution Approach 2:
An abnormality determination circuit serves as an intermediary between the physical quantity detection element and the external apparatus. This intermediary circuit receives the detection signals and performs abnormality determination by analyzing signal values and their changes, thereby providing diagnosis capability without modifying the detection element structure.
2Reliability
If self-diagnosis mechanism is provided in the physical quantity detection element, then abnormality detection is improved, but manufacturing reliability decreases due to potential failure in manufacturing process
Solution Approach 1:
The diagnosis function is extracted from the detection element and implemented as a separate circuit that processes output signals. This extraction ensures that even if the detection element has manufacturing defects, the separate abnormality determination circuit can still function independently to detect abnormalities by analyzing signal characteristics.
Solution Approach 2:
The abnormality determination circuit continuously monitors the detection signals and provides feedback about the operational status of the detection element. By analyzing the relationship between detection signal values and their changes over time, the system can identify abnormal conditions without requiring the detection element itself to have built-in diagnostic components.
3Reliability
If self-diagnosis mechanism is provided in the physical quantity detection element, then abnormality detection is improved, but cause analysis in non-destructive manner becomes difficult
Solution Approach 1:
The abnormality determination circuit provides continuous feedback by analyzing both the detection signal values and their changes over time. This dual-parameter analysis enables non-destructive cause analysis by identifying patterns in signal behavior that indicate specific types of abnormalities, such as electrode sticking or wire breaks, without requiring physical inspection or destruction of the detection element.
Solution Approach 2:
The abnormality determination circuit acts as an intermediary that translates raw detection signals into diagnostic information. By analyzing the relationship between signal values and their temporal changes, this intermediary circuit provides detailed abnormality information that aids in cause analysis while maintaining the integrity of the detection element.
4Reliability
If existing abnormality diagnosis method is applied, then abnormality detection is possible, but diagnosis cannot be performed when the physical quantity detection apparatus is in motion
Solution Approach 1:
The abnormality determination circuit continuously monitors detection signals during all operational states, including motion. By analyzing the relationship between detection signal values and their changes over time, the system can distinguish between normal operational variations during motion and actual abnormal conditions, thereby enabling diagnosis regardless of whether the apparatus is at rest or in motion.
Solution Approach 2:
The diagnosis method transitions from relying on static conditions (apparatus at rest) to analyzing dynamic parameters (relationship between signal values and their changes). This parameter-based approach allows the system to adapt to varying operational conditions, including motion, by evaluating how detection signals change over time rather than relying on fixed reference values.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable abnormality diagnosis of physical quantity detection elements in motion, improving the accuracy and reliability of inertial data and vehicle positioning, and ensuring consistent processing in portable and electronic devices.
Implementation Method 1
capacitance physical quantity detection apparatuses (physical quantity sensors) that detect physical quantities (accelerations, angular velocities, etc.) using changes of capacitance values of capacitance generated between opposed electrodes provided in physical quantity detection elements
Data Source
AI summary
A physical quantity detection circuit includes a physical quantity signal generation circuit that generates a physical quantity signal according to magnitude of a physical quantity based on a detection signal output from a physical quantity detection element, an abnormality determination circuit that determines whether or not the physical quantity detection element is potentially abnormal based on a value of the physical quantity signal and an amount of change of the value of the physical quantity signal, and an abnormality diagnostic circuit that diagnoses whether or not the physical quantity detection element is abnormal if the abnormality determination circuit determines that the physical quantity detection element is potentially abnormal.