Inertial Sensor Self-Diagnostic Contact Detection
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Solution Overview
Problem
Existing inertial sensors lack a mechanism to detect and prevent damage from excessive acceleration, which can cause the movable body to contact and potentially damage the protrusion, leading to malfunction.
Innovation Solution
Incorporating a self-diagnostic circuit and contact detection mechanism within the inertial sensor, which includes a movable body, stationary electrodes, and protrusions with detection electrodes, allowing for the detection of contact and determination of signal thresholds to assess potential damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protrusion is added to limit the displacement of the movable body, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The protrusion is pre-configured on the support substrate to limit the displacement of the movable body before excessive acceleration occurs. This preliminary structural arrangement prevents the movable body from contacting the substrate during normal operation, thereby improving reliability without requiring additional active control mechanisms.
Solution Approach 2:
The detection electrode integrated on the protrusion enables the protrusion itself to perform the function of detecting contact conditions. This self-service approach allows the limiting structure to also serve as the detection structure, avoiding the need for separate detection components and reducing overall device complexity.
2Measurement precision
If a detection electrode is integrated on the protrusion, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The detection electrode is integrated directly on the protrusion structure, merging the limiting function and detection function into a single component. This integration allows the protrusion to simultaneously limit displacement and detect contact conditions, improving measurement precision while avoiding the complexity of separate detection systems.
Solution Approach 2:
The protrusion serves multiple functions: it limits the displacement of the movable body, provides a detection electrode for contact detection, and enables self-diagnosis of the sensor. This multi-functionality approach improves measurement precision without requiring additional dedicated components for each function.
3Reliability
If a self-diagnostic circuit is added to detect contact, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The self-diagnostic circuit receives feedback from the detection electrode on the protrusion to determine whether contact has occurred. This feedback mechanism enables real-time monitoring of the movable body's displacement limits, allowing the system to detect and respond to abnormal conditions, thereby improving reliability through automated monitoring.
Solution Approach 2:
The sensor system performs self-diagnosis through the integrated detection electrode and self-diagnostic circuit, enabling the device to automatically monitor its own operational status. This self-service capability improves reliability by detecting contact conditions without requiring external monitoring systems.
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 the inertial sensor to effectively detect and prevent damage from excessive acceleration, ensuring accurate acceleration measurements and extending the sensor's operational lifespan.
Implementation Method 1
a physical quantity sensor which is configured in accordance with a locker lever principle, and which detects the acceleration based on a capacitance varying in accordance with the acceleration applied in a vertical direction
Implementation Method 2
a contact detection circuit configured to output a detection signal due to a contact between the electrode in the first portion of the movable body and the detection electrode of the protrusion
Data Source
AI summary
The inertial sensor includes a substrate, stationary electrodes provided to the substrate, an element section including a movable body which is displaceable with respect to the stationary electrodes, and which has electrodes in a first portion and a second portion opposed to the stationary electrodes, a protrusion which limits a displacement of the movable body, and which has a detection electrode in a portion opposed to the first portion of the movable body, a drive circuit for outputting a drive signal to the element section, a contact detection circuit for outputting a detection signal due to a contact between the electrode in the first portion of the movable body and the detection electrode of the protrusion, a self-diagnostic circuit for outputting a test signal to the element section when receiving the detection signal from the contact detection circuit, and a determination circuit for determining whether or not a level of a signal output by the element section in response to the test signal is out of a threshold value.