Bicycle Control Apparatus Manual Drive Force Calibration
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Solution Overview
Problem
Bicycle control apparatuses struggle to accurately detect manual drive force due to variations in signal outputs from manual drive force detectors, even when the actual force is zero, leading to inaccurate assist force determination in electrically assisted bicycles.
Innovation Solution
Incorporating a state detector and a controller that executes calibration of the manual drive force detector when specific conditions are met, such as the bicycle being operated, the crank stopping, or rotating backward, ensuring accurate detection of manual drive force by setting the signal value to zero during calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a manual drive force detector is used to detect manual drive force, then the bicycle control apparatus can determine assist force, but the signal output varies from the prescribed value even when manual drive force is actually zero, leading to inaccurate detection
Solution Approach 1:
The system performs preliminary calibration of the manual drive force detector when specific conditions are met (crank stops or rotates backward). This preliminary action adjusts the zero point of the detector before normal operation, ensuring that subsequent measurements are accurate even if the detector drifts from its prescribed value.
Solution Approach 2:
The controller continuously monitors the signal from the manual drive force detector and compares it against expected values. When the crank stops or rotates backward (indicating zero or negative manual drive force), the system provides feedback by recalibrating the detector's zero point, creating a closed-loop system that maintains measurement accuracy.
2Measurement precision
If calibration is executed continuously to maintain detection accuracy, then measurement precision improves, but device complexity and processing load increase
Solution Approach 1:
Instead of continuous calibration, the system performs calibration periodically based on specific events (when the crank stops or rotates backward). This periodic approach maintains measurement precision while significantly reducing the processing load and control complexity compared to continuous calibration.
Solution Approach 2:
The system applies calibration only when necessary (when the crank stops or rotates backward), rather than continuously. This partial action approach is sufficient to maintain accuracy because these events provide natural opportunities to reset the zero point, avoiding the excessive processing required for continuous calibration.
Data Source
AI summary
A bicycle control apparatus is basically provided for controlling a bicycle having a drive assistance electric motor. The bicycle control apparatus includes a manual drive force detector, a state detector and a controller. The manual drive force detector is configured to detect a manual drive force. The state detector is configured to detect a state of the bicycle. The controller is programmed to execute calibration of the manual drive force detector upon the controller determining that a prescribed bicycle state condition exists after power of the bicycle control apparatus is turned on.