Input Device Load Sensor Zero Point Correction Algorithm
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Solution Overview
Problem
Input devices with load sensors under a panel often experience position detection errors due to disturbances and noise from the device's weight and vibration, leading to undesired position data output even without an input operation.
Innovation Solution
A correction algorithm is implemented in the input device, which includes zero point correction, removal of high-frequency wave noise, low-load data filtering, and data trimming to accurately calculate input positions based on sensor outputs from load sensors disposed under the panel, preventing position detection errors and abnormal data output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If load sensors are disposed under the panel to detect input position, then position detection capability is provided, but position detection errors occur due to disturbances and noise from device weight and vibration
Solution Approach 1:
The patent applies preliminary action by performing zero point correction before position detection. The correction algorithm calculates correction values based on sensor outputs when no input is applied, and applies these corrections to subsequent measurements. This preparatory step eliminates the effects of device weight and panel vibration before actual input detection, preventing position detection errors rather than correcting them after occurrence.
Solution Approach 2:
The patent implements feedback by continuously monitoring sensor outputs and dynamically adjusting correction values. The correction algorithm calculates the difference between current sensor outputs and reference values, then applies corrective adjustments. This closed-loop feedback mechanism compensates for varying disturbance and noise conditions in real-time, maintaining position detection accuracy despite changing environmental factors.
2Measurement precision
If correction algorithm is implemented to improve position detection accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by adjusting correction values based on sensor output parameters. The algorithm modifies correction parameters dynamically according to the measured sensor signals, allowing the system to adapt to different operating conditions. This approach improves position detection accuracy by optimizing correction parameters for each measurement cycle while maintaining a relatively simple algorithm structure.
Solution Approach 2:
The patent implements self-service by having the correction algorithm automatically calculate and apply corrections without external intervention. The system independently determines correction values based on its own sensor outputs and reference data, then applies these corrections autonomously. This self-correcting mechanism improves position detection accuracy while avoiding the need for complex external calibration systems or manual adjustments.
Data Source
AI summary
There is provided an input device including: means for performing zero point correction on the sensor outputs of the load sensors when an absolute value of an amount of output change of each load sensor is not more than a predetermined threshold a during a certain period of measurement time; means for calculating position data and calculating a total load Z of the load sensors by using the sensor outputs; means for determining that the calculation data pieces are normal when the absolute value |dZ/dt| of the amount of change in the total load Z is not more than the threshold β; means for determining that an input is present in the calculation data pieces when the absolute value |Z| of the total load is not less than the threshold γ; and means for removing a predetermined number of first and last data pieces in the calculation data pieces.