Bicycle Gear Shift Control Using Sprocket Gate Timing
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Solution Overview
Problem
Existing bicycle component control systems struggle to perform smooth and efficient gear shifts, particularly in double downshifting and upshifting operations, due to limitations in sprocket assembly information processing and timing mechanisms.
Innovation Solution
A bicycle component controller that processes sprocket assembly information to determine shifting distances and timing, including waiting periods based on sprocket rotational angles and bicycle conditions, to optimize gear shift operations, even in scenarios with limited up or down shifting gates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional gear shift control system is used, then the basic shifting function is provided, but smooth and efficient double downshifting and upshifting operations cannot be achieved
Solution Approach 1:
The controller pre-stores sprocket assembly information including axial spacing between adjacent sprockets and shifting gate positions. Before executing a double shift command, the controller retrieves this pre-stored information to calculate the total shifting distance and determine intermediate stopping positions, enabling smooth sequential shifting without delay
Solution Approach 2:
The controller divides a double downshift or upshift command into two separate sequential shifting operations. For double downshifting, the chain is moved from the current sprocket to an intermediate sprocket first, then to the target sprocket. For double upshifting, the controller identifies intermediate stopping positions based on shifting gate information and executes shifts in stages, ensuring smooth transitions
2Reliability
If the controller waits for a predetermined period between shifts, then the shifting smoothness is improved, but the shifting time is increased
Solution Approach 1:
The controller dynamically determines the waiting period between sequential shifting operations based on real-time bicycle conditions including forward speed, cadence, and torque. When the bicycle is moving at higher speeds or under higher torque, the controller extends the waiting period to ensure smooth shifting. When conditions are favorable, the controller reduces or eliminates the waiting period, minimizing shifting time while maintaining smoothness
3Speed
If the controller performs double upshifting without intermediate stopping, then the shifting speed is improved, but the shifting smoothness deteriorates due to lack of shifting gates
Solution Approach 1:
The controller uses shifting gate information as an intermediary to identify intermediate stopping positions during double upshifting operations. Even when direct upshifting gates are not present between the current and target sprockets, the controller calculates intermediate positions based on the axial spacing and shifting gate data, moving the chain to these intermediate positions before completing the final shift, thereby ensuring smooth transitions while maintaining efficient shifting speed
Data Source
AI summary
A bicycle component controller is basically provided with a processor. The processor is configured to perform a gear shift control based on a sprocket assembly information of at least one sprocket assembly. The sprocket assembly information at least includes a single shifting distance and shifting gate information. The single shifting distance corresponds to an axial spacing between adjacent sprockets of the at least one sprocket assembly.