Bicycle Derailleur Position Control via Feedback Correction
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Solution Overview
Problem
Unintentional movements of the derailleur in bicycle gearshifts due to elasticity in the linkage and road vibrations lead to imprecise gear shifting and increased wear, caused by micro-displacements after reaching the intended position.
Innovation Solution
A method involving sequential steps to ensure the derailleur reaches and maintains the intended position, including imparting movement, waiting, checking, and optionally repositioning, using a motor and feedback signals from sensors to correct any deviations within predetermined tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the derailleur is moved into position using a motor and linkage system, then the gear shifting function is achieved, but unintentional micro-displacements occur due to elasticity in the linkage and road vibrations
Solution Approach 1:
The patent implements a feedback control system where a sensor detects the actual position of the derailleur and compares it with the intended position. When a deviation is detected, the control unit activates the motor to correct the position. This closed-loop feedback mechanism compensates for micro-displacements caused by linkage elasticity and road vibrations, ensuring the derailleur maintains accurate engagement with the selected toothed wheel.
2Measurement precision
If frequent position checks and corrections are performed, then position precision is improved, but system complexity and response time increase
Solution Approach 1:
The control system performs position checks and corrections periodically at predetermined time intervals rather than continuously. The control unit is configured to detect position deviations and activate corrections at specific moments, which reduces the overall complexity of the control logic while still maintaining adequate position precision to compensate for vibrations and elastic deformations.
Data Source
AI summary
A method for electronically controlling a bicycle gearshift comprising at least one derailleur is disclosed, comprising the sequential steps of:a) imparting a movement on the derailleur of the gearshift until the derailleur is in an intended position;b) waiting for a predetermined time period,c) performing a check whether the derailleur is in the intended position, within a possible predetermined tolerance,d) in case said check has a negative outcome, imparting a movement on the derailleur of the gearshift until the derailleur is in the intended position.A derailleur and an electronically servo-assisted bicycle gearshift comprising control electronics comprising modules adapted to carry out the method outlined above are also disclosed.