E-Bike Motor Assist Control for Changing Pedal Input
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Solution Overview
Problem
Existing human-powered vehicle control devices struggle to optimally control motor assistance based on varying parameters such as rotational speed, human driving force, acceleration, jerk, and inclination angle, leading to inconsistent assist force perception for the user.
Innovation Solution
A human-powered vehicle control device featuring an electronic controller that dynamically adjusts the motor control state based on increasing or decreasing parameters, allowing for distinct control strategies in first and second control states to optimize assist force response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the motor control response speed is increased to improve responsiveness to user input changes, then the assist force can adjust quickly, but the assist force may become insufficient during rapid changes in user effort
Solution Approach 1:
The control device dynamically adjusts the response characteristics of the motor based on the direction of change in user input. When user input increases, the system uses a first response characteristic that prioritizes rapid assist force increase. When user input decreases, a second response characteristic is applied that prevents excessive reduction of assist force, thereby maintaining sufficiency during transitions.
Solution Approach 2:
The system changes the control parameters (response characteristics) based on the direction of change in user input parameters. By detecting whether user input is increasing or decreasing, the controller switches between different response characteristic settings, optimizing both responsiveness and assist force sufficiency for each scenario.
2Device complexity
If the motor control uses a single response characteristic for all changes in user input, then the control logic is simple, but the assist force perception becomes inconsistent during increases and decreases in user effort
Solution Approach 1:
The control logic is segmented into two distinct response characteristics: a first response characteristic for when user input increases, and a second response characteristic for when user input decreases. This segmentation allows the system to optimize performance for each scenario while maintaining overall simplicity through clear conditional logic.
3Speed
If the motor output decreases rapidly when user input decreases, then the control response is fast, but the user perceives insufficient assist force
Solution Approach 1:
The control system dynamically adjusts the response characteristics based on the direction of change in user input. When user input decreases, the second response characteristic is applied, which modulates the motor output to prevent excessive reduction of assist force, thereby maintaining user perception of sufficient assistance while still responding to the change in input.
Data Source
AI summary
A human-powered vehicle control device includes a controller that is configured to control a motor assisting in propulsion of a human-powered vehicle. The controller is configured to control the motor in a first control state in a case where a first parameter increases. The first parameter includes at least one of rotational speed of a crank of the human-powered vehicle, power of human driving force input to the human-powered vehicle, acceleration of the human-powered vehicle, jerk of the human-powered vehicle, and inclination angle of the human-powered vehicle. The controller is configured to control the motor in a second control state that differs from the first control state in a case where the first parameter decreases.