Lid Angle Calculation Using Magnetometer Fusion Under Motion Noise
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Solution Overview
Problem
Existing methods for measuring the lid angle of portable devices, such as notebooks and smartphones, are unreliable due to reliance on accelerometers which are sensitive to linear accelerations and environmental vibrations, especially when the device is in a vertical position or being carried, leading to imprecise measurements.
Innovation Solution
The use of magnetometers to detect the orientation of the lid and base portions relative to the Earth's magnetic field, combined with accelerometers and gyroscopes, to calculate the lid angle, ensuring reliable measurements even in challenging orientations and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If accelerometers are used to measure lid angle, then the measurement can be performed with simple components, but the measurement precision deteriorates when the device is in vertical position or subjected to vibrations
Solution Approach 1:
The patent combines multiple sensing technologies (accelerometers, gyroscopes, and magnetometers) into a unified measurement system. The accelerometers provide gravity reference, gyroscopes capture angular velocity for dynamic orientation changes, and magnetometers supply Earth's magnetic field reference. This merging of sensors resolves the contradiction by maintaining measurement precision across all device orientations and vibration conditions while keeping the system architecture integrated and manageable.
Solution Approach 2:
The patent introduces a processing unit as an intermediary that fuses data from multiple sensors using algorithms. This intermediary component synthesizes information from accelerometers, gyroscopes, and magnetometers, compensating for the weaknesses of individual sensors. The processing unit acts as a mediator that reconciles the limited capabilities of each sensor type to achieve precise lid angle measurement in all conditions.
2Device complexity
If accelerometers are used for lid angle detection, then the device structure remains simple, but the reliability deteriorates under environmental vibrations and linear accelerations
Solution Approach 1:
The patent merges multiple sensor types with different operational characteristics to create a reliable measurement system. Accelerometers provide stable gravity reference when stationary, gyroscopes excel during dynamic movements, and magnetometers offer consistent magnetic field reference. This combination ensures high reliability across varying environmental conditions including vibrations and linear accelerations, while maintaining a unified sensor system structure.
Solution Approach 2:
The patent implements feedback mechanisms where the processing unit continuously monitors and fuses data from multiple sensors. The system uses feedback loops to weight and combine sensor readings dynamically, compensating for individual sensor limitations under different conditions. This feedback approach enhances measurement reliability by continuously adjusting the contribution of each sensor based on current operational conditions.
3Measurement precision
If filters are applied to reduce linear acceleration effects, then the measurement precision improves, but the response time increases
Solution Approach 1:
The processing unit acts as an intermediary that applies intelligent filtering and data fusion algorithms. Instead of using traditional slow filters, the system uses algorithmic approaches to weigh and combine sensor data in real-time. This intermediary processing maintains measurement precision by filtering out noise while preserving fast response characteristics through adaptive weighting of sensor inputs based on current device state.
Solution Approach 2:
The patent applies dynamic filtering where the weighting and combination of sensor data changes adaptively based on device conditions. During rapid movements, the system dynamically adjusts to prioritize gyroscopic data for fast response. During stable conditions, it emphasizes accelerometer and magnetometer data for enhanced precision. This dynamic approach resolves the contradiction by making the filtering behavior adaptive rather than static.
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
This solution provides accurate and reliable lid angle measurements, reducing noise and interference from linear accelerations and environmental factors, and is adaptive to various operational conditions, ensuring stable and real-time calibration.
Implementation Method 1
The use of magnetometers to detect the orientation of the lid and base portions relative to the Earth's magnetic field
Implementation Method 2
combined with accelerometers and gyroscopes, to calculate the lid angle
Implementation Method 3
each functional block further includes a respective gyroscope. Gyroscopes are used in order to improve the reactivity of the measurement of the angle
Data Source
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AI summary
A method for controlling an electronic apparatus (10) on the basis of a value of a lid angle (αLID) between a first hardware element (12) accommodating a first magnetometer (20) and a second hardware element (14) accommodating a second magnetometer (22), comprising: acquiring, through the magnetometers, first signals (B1, B2) representing an orientation of the hardware elements; generating, on the basis of the first signals, a calibration parameter (J1) indicative of a condition of calibration of the magnetometers; generating, on the basis of the first signals, a reliability value (K1) indicative of a condition of reliability of the first signals; calculating (50) a first intermediate value (αLID_MAG) of the lid angle (αLID) on the basis of the first signals; calculating (53) a current value of the lid angle (αLID) on the basis of the calibration parameter (J1), of the reliability value (K1) , and of the first intermediate value (αLID_MAG) ; and controlling the electronic apparatus on the basis of the current value.