Human-Powered Vehicle Control Device Dynamic Shifting Thresholds
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Solution Overview
Problem
Human-powered vehicle control devices struggle to appropriately control shifting mechanisms when the output of the motor decreases, leading to increased load on the rider and inefficient propulsion.
Innovation Solution
An electronic controller adjusts the transmission ratio by comparing a first parameter related to the vehicle's state with predetermined threshold values, changing these values based on vehicle speed, motor output, and traveling resistance to optimize shifting and reduce rider load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor output decreases as vehicle speed increases, then the shifting device cannot maintain optimal transmission ratio, but changing the threshold value dynamically resolves this issue
Solution Approach 1:
The patent applies dynamics by making the threshold value changeable based on operating conditions. Specifically, the threshold value for transmission ratio switching is dynamically adjusted according to motor output characteristics and vehicle speed, allowing the shifting device to adapt to varying propulsion demands and maintain optimal efficiency across different operating ranges.
Solution Approach 2:
The patent implements parameter changes by modifying the threshold value parameter in response to changing motor output and vehicle speed conditions. When motor output decreases with increasing speed, the threshold value is adjusted to prevent inappropriate transmission ratio switches, thereby maintaining reliable shifting control under varying propulsion conditions.
2Productivity
If the transmission ratio is changed frequently to maintain efficiency, then propulsion efficiency improves, but rider load increases
Solution Approach 1:
The patent applies feedback by continuously monitoring motor output and vehicle speed, then using this information to determine whether to adjust the threshold value and trigger a transmission ratio change. This feedback mechanism ensures that shifting occurs only when genuinely necessary for maintaining propulsion efficiency, avoiding unnecessary shifts that would increase rider load while still achieving efficiency improvements when needed.
3Device complexity
If the threshold value is fixed, then the control system is simple, but it cannot adapt to changing motor output conditions
Solution Approach 1:
The patent resolves this contradiction by implementing a dynamic threshold value that automatically adjusts based on motor output and vehicle speed conditions. This dynamic approach provides adaptability to changing propulsion conditions without requiring complex manual intervention or reconfiguration, achieving versatility through automated parameter adjustment based on real-time operating data.
Data Source
AI summary
A human-powered vehicle control device is for a human-powered vehicle. The human-powered vehicle includes a motor that applies a propulsion force to the human-powered vehicle and a shifting device that changes a transmission ratio, which is a ratio of a rotational speed of a wheel of the human-powered vehicle to a rotational speed of a crank of the human-powered vehicle. The human-powered vehicle control device includes an electronic controller that is configured to control the shifting device to change the transmission ratio in accordance with a comparison of a first parameter related to the human-powered vehicle and a predetermined threshold value. In a case where an output of the motor decreases as a vehicle speed of the human-powered vehicle increases, the electronic controller is configured to change the predetermined threshold value.