Twin-Sensor Rotary Inertial Assembly for Drift-Resistant Tilt Detection
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Solution Overview
Problem
Existing inertial sensors, such as acceleration and gyro sensors, suffer from stability issues due to drift caused by environmental changes and manufacturing offsets, making them unsuitable for precise tilt and rotation detection in dynamic instruments.
Innovation Solution
A rotational operation type inertia detecting device with an inner frame and twin inertial sensor unit, equipped with encoders and rotary power, calculates tilt and rotation angles by associating sensor outputs with encoder readings, reversing the inner frame to eliminate offset and drift, and using arithmetic processing to stabilize the detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If acceleration sensors are used for tilt detection, then responsiveness is improved, but stability deteriorates due to drift caused by environmental changes
Solution Approach 1:
The patent inverts the conventional approach by rotating the sensor unit itself rather than rotating the entire instrument. The sensor unit is mounted on a rotating platform that can be rotated 180 degrees or continuously, allowing the sensors to experience different gravitational vectors. This inversion of the rotation approach enables drift elimination through differential measurement while maintaining high responsiveness.
Solution Approach 2:
The patent implements periodic rotation of the sensor unit at specific intervals (180-degree rotation or continuous rotation). This periodic action allows the system to collect multiple measurements under different orientations, enabling the calculation of drift components that can then be subtracted from the measurements to improve stability while preserving responsiveness.
2Speed
If gyro sensors are used for rotation detection, then responsiveness is improved, but stability deteriorates due to manufacturing offsets and drift
Solution Approach 1:
The patent applies the inversion principle by rotating the gyro sensor unit itself rather than rotating the instrument. This allows the gyro to measure rotation relative to different reference frames, enabling the system to distinguish between true rotation and sensor drift through differential analysis of multiple measurement sets.
Solution Approach 2:
The patent incorporates feedback mechanisms where the rotation angle detected by encoders is fed back to the control system, which then adjusts the rotation position to achieve precise orientations (0 degrees and 180 degrees). This feedback ensures accurate alignment for drift elimination calculations while maintaining high measurement responsiveness.
3Measurement precision
If tilt sensors are used for horizontality detection, then precision is improved, but responsiveness deteriorates making them unsuitable for dynamic instruments
Solution Approach 1:
The patent merges multiple sensor types (acceleration sensors and gyro sensors) into a unified sensor unit that combines the high precision of tilt sensors with the high responsiveness of acceleration sensors. By fusing data from both sensor types and using rotational differential measurement, the system achieves both precision and responsiveness simultaneously.
Solution Approach 2:
The patent transitions from static tilt sensor measurements to dynamic measurements by rotating the sensor unit during operation. This dynamic approach allows the system to collect multiple measurements rapidly, improving responsiveness while maintaining precision through computational processing of the rotational data sequences.
4Reliability
If a rotation mechanism is added to eliminate drift, then stability is improved, but device complexity increases
Solution Approach 1:
The patent segments the instrument into distinct functional modules: a fixed main body and a separate rotatable sensor unit. This segmentation allows the complex rotation mechanism to be isolated to a specific subsystem, making it easier to manage and maintain while achieving drift elimination. The sensor unit can be independently rotated without affecting the entire instrument.
Solution Approach 2:
The patent implements a nested structure where the sensor unit is placed inside or on the rotating platform, which itself is part of the larger instrument. This nesting allows the rotation mechanism to be compact and integrated, reducing overall complexity while still providing the necessary rotational capability for drift elimination.
Data Source
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Figure 3~4D
AI summary
A rotational operation type inertia detecting device includes an inner frame (3) in which an inertial sensor unit (4) is provided and which is rotatably supported to an outer frame (2), a twin inertial sensor unit including two inertial sensors, a first encoder (12) for detecting a rotation angle between the outer frame and the inner frame, and a second encoder (17) for detecting a rotation angle between the inner frame and the twin inertial sensor unit, wherein the inertia detecting device is configured to associate a signal output by the twin inertial sensor unit with outputs of the first encoder and the second encoder, to continuously rotate the twin inertial sensor unit, to calculate a horizontal rotation angle of the inner frame and a rotation angle with respect to horizontality from a detection signal of the twin inertial sensor unit based on an angle of the second encoder, to reverse the inner frame at least once by 180° or one rotation, and to detect a vertical angle and a horizontal rotation angle with respect to verticality of the outer frame.