Bicycle Controller Motor Output During Shifting
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Solution Overview
Problem
Existing bicycle control systems fail to appropriately decrease motor output when a shifting device changes the transmission ratio, often resulting in inefficient energy use and potential inaccuracies in determining the completion of shifting actions.
Innovation Solution
A bicycle control device with an electronic controller that adjusts motor output based on shifting actions, terminating the output reduction once the shifting action is completed or a predetermined period elapses, and sets individual periods for each transmission ratio change, using rotational speed sensors to determine the effectiveness of the shifting action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the motor output is always decreased at the end of a predetermined period regardless of shifting completion, then the control is simplified, but the motor output reduction becomes inappropriate when shifting is already completed, leading to energy inefficiency
Solution Approach 1:
The system uses feedback from the shifting device completion signal and transmission ratio detection to dynamically adjust motor output control. When the shifting device detects completion of a shifting action, it signals the electronic controller to terminate the output reduction control early, rather than waiting for a fixed predetermined period to expire. This feedback mechanism ensures motor output is appropriately maintained after shifting completion, improving energy efficiency without requiring overly complex control logic.
2Device complexity
If the predetermined period for motor output reduction is fixed for all transmission ratio changes, then the control is simplified, but the energy efficiency deteriorates because different transmission ratio changes require different optimal periods
Solution Approach 1:
The system implements dynamic control parameters where the predetermined period for motor output reduction is not fixed but is set individually according to the specific transmission ratio change being performed. The electronic controller receives signals from the shifting device about which transmission ratio change is occurring and adjusts the output reduction period accordingly. This dynamic parameter adjustment optimizes energy efficiency for each specific shifting scenario while maintaining reasonable control complexity through systematic parameter management.
3Device complexity
If the transmission ratio change determination is based solely on time elapsed, then the control is simplified, but the measurement precision deteriorates because it cannot accurately determine if shifting is actually completed
Solution Approach 1:
The system employs feedback from multiple sources to accurately determine shifting completion: the shifting device provides completion signals, and the transmission ratio detection device provides actual transmission ratio measurements. The electronic controller integrates these feedback signals to precisely determine when shifting is actually completed, rather than relying solely on time-based estimates. This multi-source feedback approach achieves high measurement precision while keeping the detection system complexity manageable through coordinated signal processing.
4Speed
If the motor output is not decreased during shifting, then the propulsion performance is maintained, but harmful factors increase due to potential transmission damage and energy waste during the shifting action
Solution Approach 1:
The system applies preliminary action by decreasing motor output at the beginning of a shifting action, before the transmission completes the ratio change. The electronic controller receives a signal from the shifting device indicating a shifting action has started and proactively reduces motor output to prevent transmission damage and energy waste. This preliminary output reduction is maintained only for the duration of the shifting action, after which it is terminated when completion is detected, thus protecting the transmission without compromising overall propulsion performance.
Data Source
AI summary
A bicycle control device includes an electronic controller that controls a motor to assist propulsion of a bicycle. The electronic controller is configured to decrease an output of the motor upon determining that a shifting device is performing a shifting action to change a transmission ratio of the bicycle. The electronic controller is further configured to end the control that decreases the output of the motor before a predetermined period elapses upon determining that the shifting action is completed or the transmission ratio is changed before the predetermined period has elapsed. The electronic controller is further configured to end the control that decreases the output of the motor upon determining that the predetermined period has elapsed in a case where the shifting action or the change in the transmission ratio is uncompleted even though the predetermined period has elapsed.