E-bike Drive Control Using Stored Torque Data

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Solution Overview

Problem

Conventional e-bikes and pedelecs interrupt the electric drive when the crank device is not operated, leading to immediate loss of propulsion, which can cause discomfort and increase the risk of accidents, especially on uneven terrain or inclines.

Innovation Solution

A control method that acquires and stores torque data to determine a driving force request and condition, allowing the electric drive machine to continue providing power based on muscle power input, ensuring seamless transition and preventing immediate interruption, even when the crank device is not operated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electric drive is interrupted when the crank device is not operated, then regulatory requirements are met, but propulsion is immediately lost causing discomfort and safety risks

Engineering Contradiction:
Improvesafety and comfortVSAvoidseamless propulsion
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control device stores torque data acquired during crank operation in advance. When the crank stops, the controller uses this pre-stored torque information to determine whether to maintain electric drive, enabling proactive decision-making rather than immediate interruption, thus ensuring continuous propulsion while meeting regulatory requirements.

Inventive Principle:
Principle #10Preliminary action

2Ease of operation

If the electric drive continues without interruption, then propulsion continuity is maintained, but regulatory requirements for crank operation monitoring are not met

Engineering Contradiction:
Improvecontinuous propulsionVSAvoidregulatory compliance
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control device continuously monitors crank operation status and uses stored torque data as feedback to determine whether to maintain or interrupt electric drive. This feedback mechanism ensures that the system responds appropriately to crank operation changes while maintaining propulsion continuity when conditions warrant, thus satisfying both regulatory requirements and propulsion smoothness.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If torque data is stored for a long period, then accurate drive force determination is possible, but memory resources are consumed

Engineering Contradiction:
Improvedrive force accuracyVSAvoidmemory storage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The control device stores torque data for a predetermined period that is sufficient to accurately determine drive force requirements but not excessively long. This partial storage approach balances measurement precision needs with memory resource constraints, storing only the necessary historical torque data needed for accurate drive force determination without unnecessary resource consumption.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4309987A1Method for controlling an electric drive of a two-wheeled vehicle and control device for carrying out the method
Publication Date: 2024.01.24 KLIEBER JOCHEN
  • EP4309987A1 patent drawingFigure 1
  • EP4309987A1 patent drawingFigure 2
  • EP4309987A1 patent drawing

AI summary

A method for controlling an electric drive of a two-wheeler is provided, which can be driven via a drive wheel on the basis of a rider's muscle force introduced into a crank mechanism of the two-wheeler and a drive force of an electric drive motor provided on the two-wheeler.The method comprises the following steps: acquiring torque data (S1) relating to the driving force at the drive wheel of the two-wheeler; determining whether the rider has requested (S3) a driving force from the electric motor; determining whether a driving condition (S4) exists for the electric motor to provide the driving force; and controlling the electric drive motor (S5) to provide the driving force after determining whether the rider has requested and whether the driving condition exists. Furthermore, a control device is provided for carrying out the method.