Orientation-Independent Sensor Drop Detection
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Solution Overview
Problem
Existing drop detection devices fail to accurately determine if a sensor has been dropped, as they rely on acceleration becoming 0 G, making it impossible to detect drops if the sensor is not in a specific orientation.
Innovation Solution
A sensor system that includes a sensor with multiple detection axes, a storage unit for installation information, and a drop determination unit that calculates the absolute difference between detected accelerations and gravitational acceleration values to determine if the sensor is dropped, regardless of orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the drop detection device uses the fact that acceleration becomes 0 G during drop, then it can detect drop state, but it cannot determine that drop is made after the drop
Solution Approach 1:
The invention transitions from detecting only the magnitude of acceleration (1D) to detecting both magnitude and direction of acceleration (3D). By using a 3-axis acceleration sensor and comparing the direction of gravitational acceleration before and after drop, the system can determine post-drop state. The direction information provides an additional dimension that enables determination after the drop event, resolving the time loss issue.
2Reliability
If the sensor system continuously monitors acceleration to determine drop, then it can detect drop events, but it consumes more power
Solution Approach 1:
The system performs preliminary action by recording the direction of gravitational acceleration before drop occurs (normal state). This pre-recorded reference value is stored and later used for comparison after drop. By having the reference ready in advance, the system can quickly determine post-drop state without continuous monitoring, reducing power consumption while maintaining reliability.
3Adaptability or versatility
If the system uses multiple detection axes to determine drop regardless of orientation, then it improves adaptability, but it increases calculation complexity
Solution Approach 1:
The system achieves universality by making the drop detection function independent of sensor orientation. The 3-axis acceleration sensor and direction comparison method work regardless of how the sensor is mounted. The same algorithm handles all orientation cases (vertical, horizontal, angled), making the system universally applicable without requiring separate detection logic for each orientation, thus managing complexity while improving adaptability.
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 accurate detection of sensor drops even after the event, reducing the risk of incorrect arithmetic calculations and conserving power by not outputting data from dropped sensors.
Implementation Method 1
a sensor that is provided in a structure and detects an acceleration... gravitational acceleration value in the direction of the detection axis specified based on the installation information
Data Source
AI summary
A sensor system includes a sensor that is provided in a structure and detects an acceleration, a storage unit that stores installation information indicating a relationship between a direction of a gravitational acceleration and a direction of a detection axis of the sensor, and a drop determination unit that determines whether or not the sensor is dropped based on a representative value of accelerations in the direction of the detection axis detected by the sensor and a gravitational acceleration value in the direction of the detection axis specified based on the installation information.