Bicycle Shift Timing Control Using Cadence and Torque Feedback
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Solution Overview
Problem
Riders of human-powered vehicles often experience shift shock due to improper timing of gear shifts, which can be uncomfortable and is a challenge for inexperienced riders to avoid.
Innovation Solution
A shifting system that includes a controller receiving cadence and driving torque data from sensors to determine a permitted shift timing range, restricting gear shifts within this range to prevent shift shock, and using a map to estimate travel distance and speed for precise timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gear shift is performed without cadence control, then shifting operation is simple, but shift shock occurs causing rider discomfort
Solution Approach 1:
The system uses cadence sensors to continuously monitor riding conditions and feeds this information back to the controller, which automatically adjusts shift timing to avoid shift shock. This feedback mechanism eliminates the need for rider skill while preventing harmful shift shock.
Solution Approach 2:
The shifting system performs self-adjustment by automatically determining optimal shift timing based on cadence data without requiring rider intervention or skill. The system serves itself by making intelligent decisions about when to shift gears.
2Object-affected harmful factors
If gear shift timing is controlled based on cadence, then shift shock is prevented, but system complexity increases
Solution Approach 1:
The patent replaces complex mechanical timing mechanisms with electronic cadence sensing and control. Sensors and microcontrollers substitute for mechanical timing devices, reducing mechanical complexity while achieving precise shift timing control.
Solution Approach 2:
The system monitors cadence parameter changes and uses these changes to determine optimal shift timing. By tracking cadence parameter variations, the system automatically identifies when shift shock will occur and prevents it, managing complexity through parameter-based control.
3Reliability
If gear shift is restricted to permitted cadence range, then shift performance is improved, but shifting flexibility is reduced
Solution Approach 1:
The system dynamically adjusts the permitted cadence range based on current riding conditions, gear position, and torque requirements. Rather than using fixed cadence limits, the control system adapts the acceptable shift window in real-time, maintaining reliability while preserving flexibility.
Solution Approach 2:
The system changes operational parameters (cadence range limits) based on riding context. By adjusting the permitted cadence range dynamically according to gear selection, torque demands, and riding style, the system maintains both reliability and adaptability.
Data Source
AI summary
A shifting system for a human-powered vehicle comprises a controller. The controller is configured to receive a driving torque and a cadence of the human-powered vehicle from at least one sensor. The controller is configured to determine a permitted shift timing based on the driving torque and the cadence. The controller is further configured to control a shift mechanism to perform a gear shift during the permitted shift timing in accordance with a permitted cadence range and a first threshold of the driving torque.