E-Bike Drive Control for Lateral Rocking Pedaling

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Solution Overview

Problem

Existing electric power-assisted bicycles struggle to provide optimal assistance when riders pedal while rocking the bicycle body laterally, as the current systems do not accurately differentiate between normal pedaling and lateral rocking, leading to inefficient torque application.

Innovation Solution

A drive system equipped with sensors to detect pedaling force, lateral rocking, and rotation position, along with a controller that switches between two modes to adjust assist torque based on these inputs, ensuring more comfortable and efficient power assistance during lateral pedaling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the electric motor outputs assist torque based on normal pedaling detection, then the assist torque is appropriate for normal pedaling, but the assist torque is insufficient when the rider pedals while rocking the bicycle body laterally

Engineering Contradiction:
Improveassist torqueVSAvoidadaptation to different pedaling modes
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The control system dynamically switches between normal-pedaling control and lateral-rocking control modes based on real-time detection of bicycle body inclination and pedaling state. This dynamic adaptation allows the assist torque to be optimized for different pedaling conditions, resolving the contradiction between maintaining appropriate torque for normal pedaling and providing sufficient torque for lateral rocking pedaling.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes control parameters (assist torque magnitude and characteristics) based on the detected pedaling mode. When lateral rocking is detected through inclination sensors, the control parameters are adjusted to provide larger assist torque, thereby adapting the power output to match the rider's needs in different pedaling scenarios.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the controller uses only pedaling force detection, then the control system is simple, but it cannot accurately differentiate between normal pedaling and lateral rocking pedaling

Engineering Contradiction:
Improvecontrol system complexityVSAvoidpedaling mode detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The control system integrates multiple sensor functions into a unified control framework. The inclination sensor serves dual purposes: detecting bicycle body tilt for lateral rocking detection and providing data for determining pedaling mode. This multi-functional approach enhances measurement precision without proportionally increasing system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements feedback control by continuously monitoring inclination sensor output and using it to determine whether the rider is performing lateral rocking pedaling. This feedback mechanism enables accurate differentiation between pedaling modes, allowing the controller to adjust assist torque appropriately while maintaining a relatively simple overall system architecture.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3263436B1Electric power-assisted bicycle, drive system and control method therefor
Publication Date: 2019.08.07 YAMAHA MOTOR CO LTD
  • EP3263436B1 patent drawingFigure 1
  • EP3263436B1 patent drawingFigure 2
  • EP3263436B1 patent drawingFigure 3

AI summary

An electric power-assisted bicycle, comprising: a torque sensor (41) for detecting pedaling force applied to the pedal (2a); an inclination angle sensor (51) for detecting rocking of the bicycle body in a lateral direction; an electric motor (21) that assists drive of a drive wheel driven by pedaling of the rider; and a controller (30) that controls the electric motor on the basis of the pedaling force. The controller has a first mode and a second mode as control modes of the electric motor. The second mode is executed when the controller determines that the rider pedals the bicycle while rocking the bicycle body in the lateral direction. The controller executes different control in the second mode from that in the first mode to assist the drive of the drive wheel.