Bicycle Trainer Variable-Ratio Transmission Inertia Simulation

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Solution Overview

Problem

Existing bicycle trainers fail to accurately simulate the dynamic experience of outdoor cycling, particularly the change in inertia and gear shifting, as they typically rely on flywheels or constant braking resistance, neglecting the real-world variations in inertia and gear ratio.

Innovation Solution

The bicycle trainer employs a variable-ratio transmission system and time-variable braking resistance to simulate the inertia and gear shifting experience of outdoor cycling, without a flywheel, by adjusting the rotational speed of the pedals in relation to virtual forward speed and incorporating a visual indicator for setting changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a flywheel is used to simulate inertia, then the device complexity is reduced, but the realism of gear shifting and inertia changes is insufficient

Engineering Contradiction:
Improvestructure simplicityVSAvoidrealism of gear shifting simulation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent creates a virtual copy of the transmission system through software simulation rather than physically replicating it with mechanical components. The control unit calculates and simulates the effects of gear ratios, chain derailleur mechanics, and inertial changes that would occur in an outdoor cycling scenario, providing realistic feedback without requiring complex mechanical duplication.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical flywheel inertia system with an electronic control system that calculates and applies equivalent resistive forces. Instead of using physical mass to simulate inertia, the system uses computational models to determine the appropriate resistance levels based on virtual gear selection and cycling conditions, substituting mechanical inertia with electronically controlled resistance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If constant braking resistance is applied, then the control system is simple, but the dynamic cycling experience is lost

Engineering Contradiction:
Improvecontrol system simplicityVSAvoiddynamic resistance adjustment
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic resistance adjustment where the braking resistance continuously changes based on multiple variables including virtual gear ratio, simulated cycling speed, terrain conditions, and rider power output. The control unit dynamically calculates the optimal resistance level to maintain realistic cycling dynamics, allowing the system to adapt to different riding scenarios and provide an authentic outdoor cycling experience.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms where the control unit continuously monitors cycling parameters and adjusts the braking resistance accordingly. By measuring the rider's pedaling speed, power output, and the selected virtual gear ratio, the system provides real-time feedback through resistance adjustment, creating a responsive and adaptive training environment that mirrors outdoor cycling conditions.

Inventive Principle:
Principle #23Feedback

3Device complexity

If gear ratio changes are simulated without inertia changes, then the device complexity is low, but the authenticity of outdoor cycling experience is reduced

Engineering Contradiction:
Improvetransmission system simplicityVSAvoidauthenticity of cycling experience
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the simulation parameters to include inertial effects associated with different gear ratios. When the rider selects different virtual gears, the system adjusts not only the resistance level but also the simulated inertial characteristics, such as the effective mass and acceleration properties that would be experienced with different gear configurations outdoors. This provides authentic feedback about how different gears affect cycling dynamics.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3648852B1Bicycle trainer and method of its operation
Publication Date: 2024.10.30 TACX BV
  • EP3648852B1 patent drawingFigure 1~2

AI summary

Bicycle trainer comprising a seat, handlebars and rotatable pedals, and an electronically variable brake acting directly or indirectly on the rotatable pedals with a braking resistance that depends on a predetermined setting of a computer-controller, which predetermined setting is variable and depends on selected parameters to reflect simulated cycling conditions comprising at least one of a road, wind conditions and a cyclist, wherein the bicycle trainer excludes a flywheel and includes a variable-ratio transmission system and that the predetermined setting of the braking resistance also depends on a setting or change of setting of the variable-ratio transmission system so as to simulate a level of inertia or change of inertia as experienced by an outdoor cyclist when changing the variable-ratio transmission system.