Bicycle Gear Shifting Control for Stable Cadence and Fewer Shifts
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Solution Overview
Problem
Existing bicycle shifting systems face a conflict between providing optimal pedaling comfort and minimizing unnecessary gear changes, often resulting in inefficient and uncomfortable operation.
Innovation Solution
A method for controlling gear shifts by ascertaining a reference shifting point where the change in pedaling frequency is symmetrical to a reference pedaling frequency, using shifting hysteresis to define target points, and adapting to current driving conditions for optimal gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic gear changing is implemented using fixed shifting thresholds, then gear changes are triggered automatically, but unnecessary frequent gear changes occur reducing pedaling comfort
Solution Approach 1:
The patent applies dynamics by making the shifting threshold variable rather than fixed. The control device dynamically adjusts the shifting threshold based on the current gear ratio, using a dynamically determined reference pedaling frequency that changes with each gear step. This allows the automatic shifting system to adapt to different mechanical conditions, preventing unnecessary frequent gear changes while maintaining optimal pedaling comfort across the entire gear range.
Solution Approach 2:
The patent changes the parameter of pedaling frequency from a fixed reference value to a dynamically varying reference value that depends on the current gear ratio. By determining a specific reference pedaling frequency for each gear step and using it to calculate the shifting threshold, the system optimizes the shifting points for each gear combination, thereby reducing unnecessary gear changes and improving overall pedaling comfort.
2Ease of operation
If shifting thresholds are optimized for optimal pedaling frequency, then pedaling comfort is improved, but the system complexity increases
Solution Approach 1:
The patent applies self-service by enabling the control device to automatically determine the reference pedaling frequency and calculate the appropriate shifting threshold without requiring complex external input or manual adjustment. The system uses its own internal data (current gear ratio) to dynamically adjust the shifting parameters, simplifying the overall control architecture while maintaining optimal pedaling comfort.
Solution Approach 2:
The patent applies preliminary action by pre-determining reference pedaling frequencies for different gear steps and storing them in the control device. This allows the system to quickly retrieve and use the appropriate reference frequency when a gear change occurs, avoiding the need for complex real-time calculations and reducing control system complexity while maintaining optimal shifting performance.
Data Source
AI summary
A method for controlling a gear shifting mechanism of a bicycle is disclosed. The method includes determining at least one reference shifting point using a control unit mounted on the bicycle, wherein the control unit determines the at least one reference shifting point such that, when a gear change occurs at the at least one reference shifting point, a change in pedalling frequency caused by the gear change is symmetrical to a reference pedalling frequency associated with the at least one reference shifting point. The method further includes controlling the gear shifting mechanism using the control unit based upon the determined at least one reference shifting point.