Gimbal-Based Inclination Sensor Drift Suppression
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Solution Overview
Problem
Existing inclination sensors 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 form factor when combining tilt and acceleration sensors.
Innovation Solution
An inclination sensor utilizing a gimbal mechanism with motors and encoders to continuously rotate an acceleration sensor, determining inclination angles based on detected rotation angles when output values indicate maximum, minimum, or median values, thereby suppressing drift and eliminating the need for a tilt sensor.
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 the detection accuracy deteriorates due to drift in output values caused by environmental changes
Solution Approach 1:
The acceleration sensor is continuously rotated around the optical axis by a rotation drive mechanism, transforming it from a static sensor into a dynamic one. This continuous rotation allows the system to collect multiple measurement samples over different orientations, enabling statistical processing to identify and eliminate drift effects while maintaining a compact device structure with only one acceleration sensor.
Solution Approach 2:
The acceleration sensor undergoes periodic rotation at a controlled speed, creating a cyclic measurement pattern. By performing measurements over multiple rotation cycles and processing the periodic data sequences, the system can distinguish between genuine inclination signals and drift components, thereby improving detection accuracy without requiring additional sensors or increasing device size.
2Measurement precision
If both a tilt sensor and an acceleration sensor are used to ensure detection accuracy across all attitudes, then the detection accuracy is improved, but the device size increases
Solution Approach 1:
The single acceleration sensor is made multi-functional through continuous rotation. By rotating the sensor around the optical axis, it can detect inclination angles in all directions and attitudes sequentially, replacing the need for multiple dedicated sensors. This universal approach allows one sensor to perform the function that previously required both a tilt sensor and an acceleration sensor, thereby reducing device size while maintaining comprehensive detection accuracy.
3Measurement precision
If the acceleration sensor is continuously rotated to suppress drift, then the detection accuracy is improved, but the device complexity increases due to additional motors and encoders
Solution Approach 1:
The rotation drive mechanism that rotates the acceleration sensor is integrated with the existing gimbal mechanism structure. The rotation drive unit shares structural elements and control resources with the gimbal system, merging two functions (gimbal movement and sensor rotation) into a coordinated system. This integration reduces the overall device complexity compared to adding a completely separate rotation mechanism, while still achieving drift suppression through continuous sensor rotation.
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 with reduced sensor size by focusing on the timing of output value extremes rather than high-accuracy output values from the acceleration sensor, effectively mitigating environmental influences and eliminating the need for a tilt sensor.
Implementation Method 1
one of coordinate axes of the acceleration sensor coincides with at least any one of a direction of gravity, a direction opposite to gravity
Implementation Method 2
gimbal mechanism that has a first shaft and a second shaft perpendicular to the first axis and that is rotatably supported around the first shaft and the second shaft
Data Source
AI summary
An inclination sensor that can accurately detect an inclination angle with respect to a horizontal direction while suppressing drift in output values from an acceleration sensor and a data acquisition device including the inclination sensor are described. The inclination sensor includes a gimbal mechanism that is rotatably supported around a first shaft and a second shaft, a first motor that rotates the first shaft, a second motor that rotates the second shaft, a first encoder that detects a rotation angle of the first shaft, a second encoder that detects a rotation angle of the second shaft, an acceleration sensor that is disposed in the gimbal mechanism, and a control unit that arithmetically determines the inclination angle with respect to the horizontal direction.