Bicycle Control Device Preventing Unintended Walk Mode Activation
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Solution Overview
Problem
Existing motor assist bicycles often inadvertently drive in walk mode during normal riding due to the walk switch being used to adjust assist drive force, leading to unintended motor operation.
Innovation Solution
A bicycle control device with an input unit and controller that switches between ride mode and walk mode, driving the motor in accordance with the operation of the input unit, ensuring intended assistance during walking and preventing unintended motor operation during riding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the walk switch is used to adjust assist drive force during normal riding, then the rider can control motor assistance levels, but the motor may be driven in walk mode when the rider does not intend to do so
Solution Approach 1:
The system dynamically changes the function of the input unit based on the current operational mode. When in ride mode, the input unit adjusts assist drive force levels. When in walk mode, the input unit controls motor drive in correspondence with its operation. This dynamic reconfiguration resolves the contradiction by ensuring the switch serves the appropriate function based on context, preventing unintended walk mode activation during riding while maintaining ease of operation.
2Device complexity
If a single input unit is used for both ride mode assist adjustment and walk mode activation, then device complexity is reduced, but unintended mode switching occurs
Solution Approach 1:
The input unit is designed with multi-functionality to serve both ride mode assist adjustment and walk mode activation/control. The controller determines the current mode and routes the input unit's signal appropriately: in ride mode it adjusts assist levels, in walk mode it controls motor drive. This universal design reduces device complexity while maintaining reliability through context-aware signal interpretation.
3Reliability
If the motor is driven in walk mode during normal riding, then unintended speed increases occur, but adding separate control mechanisms increases device complexity
Solution Approach 1:
The controller continuously monitors the operational mode (ride or walk) and uses this feedback to determine how to interpret input unit signals. This feedback mechanism ensures that when in ride mode, walk mode activation is prevented, and when in walk mode, the motor is properly controlled. The feedback-based control resolves the contradiction by preventing unintended motor operation without requiring separate physical control mechanisms.
Data Source
AI summary
A bicycle control device controls a motor to assist driving of a wheel of a bicycle. The bicycle control device includes a controller configured to control the motor and an operation unit configured to be operated to switch operation modes of the motor. The controller includes at least a walk mode as the operation modes. In a case that a rotation speed of a wheel becomes lower than or equal to a predetermined value while the motor is driven in the walk mode, the controller is configured to control the motor so as to gradually decrease output of the motor and then stop driving the motor.