Wearable Input Device Using Inertial Sensor Fusion
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Solution Overview
Problem
Existing input devices that detect body part movements for input operations often require users to learn specific operations, leading to discomfort and errors due to noise and inaccuracies in posture detection.
Innovation Solution
A wearable input device with a sensor unit for angular velocities and acceleration, a reference posture specification unit, a rotation matrix calculator, a characteristic value calculator, and a command specification unit that transforms angular velocities into usable commands for controlling devices, allowing natural body motions to be translated into device inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a user performs input operations by directly touching the touch panel, then the input operation is simple and direct, but the user cannot operate the terminal from a free position or free posture
Solution Approach 1:
The patent introduces a wearable input device as an intermediary between the user's body movements and the terminal operations. This device includes sensors (accelerometer, gyroscope) that detect body movements and convert them into input signals, allowing users to operate the terminal from free positions and postures without directly touching the screen.
Solution Approach 2:
The patent replaces the mechanical direct-touch system with a sensor-based detection system. Instead of requiring physical contact with the touch panel, the system uses accelerometers and gyroscopes to detect body movements, substitutes mechanical input with sensor data processing, and transforms body motion into digital commands.
2Adaptability or versatility
If the device detects posture angle from acceleration during motion, then the input operation can be performed from free position, but noise causes errors in posture detection
Solution Approach 1:
The patent merges the outputs of multiple sensors (accelerometer and gyroscope) to achieve more accurate posture detection. The accelerometer provides acceleration data while the gyroscope provides angular velocity data, and by combining these measurements through sensor fusion algorithms, the system compensates for the noise and errors that would occur if using either sensor alone.
Solution Approach 2:
The patent implements feedback mechanisms to correct posture detection errors. The system continuously monitors sensor data and uses feedback loops to adjust and refine posture angle calculations, compensating for noise and drift in real-time to maintain measurement precision despite the presence of environmental disturbances.
3Extent of automation
If the device requires users to learn specific operations for body part movement detection, then the input method can be implemented, but users feel uncomfortable and require significant effort to learn
Solution Approach 1:
The patent implements self-service functionality where the system automatically detects and interprets body movements without requiring users to learn or perform specific gestures. The sensor-based system autonomously identifies meaningful movements and converts them into appropriate input commands, eliminating the need for users to study or memorize operation procedures.
Solution Approach 2:
The patent changes the parameters of movement detection from requiring specific, learned gestures to detecting natural body movements through changes in acceleration and angular velocity. By adjusting the detection parameters to recognize a broader range of natural motions, the system makes operation intuitive and eliminates the learning curve associated with specific gesture protocols.
4Measurement precision
If the device transforms angular velocities from the device coordinate system to the reference posture coordinate system, then the input accuracy is improved, but the calculation complexity increases
Solution Approach 1:
The patent performs preliminary actions by pre-defining the reference posture coordinate system and pre-calculating transformation matrices. The system establishes the relationship between the device coordinate system and the reference posture coordinate system in advance, so that during actual operation, only simple matrix multiplication is required rather than complex real-time calculations.
Solution Approach 2:
The patent uses copying by creating a virtual reference coordinate system that mirrors the physical reference posture. Instead of performing complex real-time transformations, the system copies the reference posture geometry and uses this virtual model to simplify the transformation calculations, reducing computational complexity while maintaining 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
Enhances user convenience by allowing input operations in free body positions and reduces the learning burden, while minimizing noise and inertia-related errors, enabling accurate and intuitive control of devices.
Implementation Method 1
a sensor unit configured to obtain angular velocities and an acceleration in a first coordinate system fixed in the input device
Implementation Method 2
a rotation matrix calculator configured to calculate a rotation matrix that transforms the angular velocities in the first coordinate system into angular velocities in the second coordinate system using the acceleration in the first coordinate system
Data Source
AI summary
An input device, that is worn on a portion of a user's body, includes: a sensor unit configured to obtain angular velocities and an acceleration in a first coordinate system fixed in the input device; a reference posture specification unit configured to generate a second coordinate system for a reference posture of the user; a rotation matrix calculator configured to calculate a rotation matrix that transforms the angular velocities in the first coordinate system into angular velocities in the second coordinate system using the acceleration in the first coordinate system; a characteristic value calculator configured to calculate characteristic values in the second coordinate system using the angular velocities in the second coordinate system; a command specification unit configured to specify a command according to the characteristic values; and a transmitter configured to transmit the command to the controller.