Gimbal Inclination Sensing Using Frequency Analysis Against Drift
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Solution Overview
Problem
Existing inclination sensors for data acquisition devices face challenges in accurately detecting inclination angles with respect to a horizontal direction due to drift in output values from acceleration sensors, which are affected by environmental changes, and require a larger size when combining tilt and acceleration sensors for improved accuracy.
Innovation Solution
An inclination sensor that uses a gimbal mechanism with an acceleration sensor, where the control unit simultaneously rotates the sensor around two axes and applies frequency analysis to the output values to determine the inclination angle, eliminating the need for a tilt sensor and reducing size while maintaining accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If only an acceleration sensor is used to reduce device size, then the device size is reduced, but detection accuracy deteriorates due to drift in output values from the acceleration sensor
Solution Approach 1:
The acceleration sensor is rotated dynamically around two orthogonal axes (first shaft and second shaft) that are perpendicular to each other. By rotating the sensor in multiple directions and analyzing the temporal changes in output values, the system can distinguish between drift components and actual inclination signals, thereby maintaining detection accuracy without requiring a tilt sensor.
Solution Approach 2:
The control unit performs periodic rotation of the acceleration sensor around the first shaft and second shaft at controlled frequencies. By applying frequency analysis to the periodic output signals, the system can identify and separate drift components from valid inclination measurements, ensuring accurate detection while using only a single acceleration sensor.
2Measurement precision
If both a tilt sensor and an acceleration sensor are used to ensure detection accuracy, then detection accuracy is improved, but device size increases
Solution Approach 1:
The single acceleration sensor is made multi-functional by rotating it around two orthogonal axes. The same sensor serves both to detect inclination angles and to characterize drift through its rotational motion patterns. This eliminates the need for a separate tilt sensor while maintaining the ability to detect inclination accurately across a wide range of angles.
Solution Approach 2:
The system changes the operational parameters of the acceleration sensor by rotating it around two orthogonal axes at different frequencies. By analyzing the frequency-domain characteristics of the output signals, the system can extract inclination information while filtering out drift components, achieving accurate detection with a single sensor.
3Measurement precision
If the acceleration sensor is rotated around two orthogonal axes using frequency analysis, then detection accuracy is maintained despite drift, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical inclination sensing mechanisms (such as tilt sensors with moving parts) with a simpler rotational actuation system combined with frequency-domain signal processing. The control unit rotates the acceleration sensor using motors and uses software-based frequency analysis to extract inclination information, reducing mechanical complexity while maintaining or improving detection accuracy.
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
The solution ensures accurate detection of inclination angles in real-time, even with drift in acceleration sensor outputs, and reduces the overall size of the sensor by using frequency analysis instead of high-accuracy output values, allowing for real-time sensing without the need for a tilt sensor.
Implementation Method 1
an inclination angle with respect to a horizontal direction include a tilt sensor... detect an inclination angle of a data acquisition device, such as a surveying device or an image acquisition device, with respect to a horizontal direction
Data Source
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AI summary
The inclination sensor includes a gimbal mechanism rotatably supported around a first shaft and a second shaft, a first motor, a second motor, an acceleration sensor disposed in the gimbal mechanism with an origin point of coordinate axes being coincident with a point of intersection of a shaft center of the first shaft and a shaft center of the second shaft, and a control unit that simultaneously rotates the first shaft and the second shaft to continuously rotate the acceleration sensor around the first shaft and the second shaft and applies frequency analysis to the output values from the acceleration sensor to arithmetically determine the inclination angle with respect to the horizontal direction.