Chainless E-Bike Pedal Torque Control to Prevent Slip-Through

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Solution Overview

Problem

Existing chainless electric bicycles suffer from pedal slip-through phenomena due to weak pedal reaction forces, leading to discomfort, and lack a stable pedal feeling similar to bicycles with chains.

Innovation Solution

A method and system that control the electric bicycle by separately using a pedal speed controller to generate pedal torque commands, independent of wheel speed, incorporating proportional-integral-differential controllers to adjust torque based on pedal and wheel inertia, and applying assist ratios to optimize pedal feeling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If motor torque is generated by rotating the pedal and pedal feeling is generated based on motor torque, then the pedal feeling can be controlled to become heavier or lighter based on wheel speed, but the pedal slip-through phenomenon occurs when the pedal is pressed strongly due to weak pedal reaction force

Engineering Contradiction:

Improvepedal feelingVSAvoidpedal reaction force

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent divides the control system into two independent controllers: a wheel speed controller for acceleration performance and a pedal speed controller for pedal feeling. This segmentation allows each controller to independently optimize its function without interference, preventing the pedal slip-through phenomenon by ensuring the pedal controller provides sufficient reaction force regardless of wheel speed conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a separate pedal speed parameter that is independent of wheel speed parameter. By changing the control parameter from wheel speed to pedal speed, the system can adjust pedal feeling based on actual pedal rotation characteristics rather than wheel speed, providing appropriate pedal reaction force even when the wheel speed is low or the bicycle is stationary.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the pedal feeling is generated based on the wheel speed, then the control can be simplified, but the pedal feeling becomes unstable and does not resemble a bicycle with a chain

Engineering Contradiction:

Improvecontrol systemVSAvoidpedal feeling stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The patent separates the control system into distinct wheel speed controller and pedal speed controller modules. This segmentation allows the pedal speed controller to focus specifically on generating stable pedal feeling by monitoring only pedal rotation speed, independent of wheel speed variations, thereby achieving chain-like pedal stability without excessive system complexity.

Inventive Principle:

Principle #1Segmentation

3Device complexity

If a single wheel speed controller is used to control both acceleration and pedal feeling, then the device complexity is reduced, but the control cannot be optimized for each system separately

Engineering Contradiction:

Improvecontroller structureVSAvoidsystem optimization

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements separate wheel speed controller and pedal speed controller, each optimized for its specific function. The wheel speed controller handles acceleration performance while the pedal speed controller handles pedal feeling, allowing each to be independently tuned and optimized without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dual-controller architecture provides multi-functionality where the wheel speed controller manages acceleration and the pedal speed controller manages pedal feeling, allowing the system to adapt to different operating conditions and user preferences for both performance aspects simultaneously.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Prevents pedal slip-through and provides a stable pedal feeling akin to bicycles with chains, independent of vehicle characteristics, allowing for customizable pedal feedback.

Implementation Method 1

the generator (alternator) connected to the pedal is controlled to generate a pedal load similar to that of a bicycle having a chain

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

driving a motor with electricity

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS12565283B2Method and system for controlling electric bicycle

Publication Date: 2026.03.03 HL MANDO CORP

AI summary

A method for controlling an electric bicycle comprises: detecting a pedal speed and a wheel speed; generating a wheel torque command by applying a wheel speed parameter to a difference between a wheel speed command generated by multiplying the pedal speed by a gear ratio and the wheel speed; generating a pedal torque command by applying a pedal speed parameter to the difference between the wheel speed command and the wheel speed; controlling a motor based on the wheel torque command; and controlling a generator based on the pedal torque command.