Bicycle Sensor Data Correction for Aerodynamic Drag

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Solution Overview

Problem

Current methods for determining the aerodynamic drag coefficient of a bicycle, such as using air pressure sensors or satellite systems, suffer from low accuracy due to distortion caused by movement and the Bernoulli effect, which is inadequate for precise measurements needed for air resistance coefficient calculation.

Innovation Solution

A method utilizing at least two sensors, including an air pressure sensor and a dynamic pressure sensor system, to detect and correct ambient pressure values by accounting for dynamic pressure and relative air speed, along with a yaw sensor to consider wind direction, thereby improving measurement accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If air pressure sensors are used to detect ambient pressure on a moving bicycle, then measurement resolution is improved, but measurement accuracy deteriorates due to distortion from movement and the Bernoulli effect

Engineering Contradiction:
Improvemeasurement resolutionVSAvoidmeasurement accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

A correction device is introduced as an intermediary element that receives both the ambient pressure measurement and dynamic pressure measurement, then processes them together to produce a corrected ambient pressure value. This mediator eliminates the distortion caused by bicycle movement while preserving the high resolution of the air pressure sensor.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses dynamic pressure measurements as feedback to correct the ambient pressure measurements. The dynamic pressure information about the bicycle's motion through the air is fed back into the measurement system to compensate for the distortions, allowing accurate ambient pressure determination despite movement.

Inventive Principle:
Principle #23Feedback

2Reliability

If the air pressure sensor is placed inside a housing to reduce distortion, then measurement accuracy is improved, but significant distortions still occur due to the Bernoulli effect

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidBernoulli effect distortion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system converts the harmful Bernoulli effect into a useful measurement by actively measuring the dynamic pressure caused by the effect. Instead of trying to eliminate the distortion, the invention uses the distortion itself as information to correct the ambient pressure measurement, turning a harmful factor into a beneficial correction mechanism.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If satellite systems are used to determine altitude, then high accuracy is achieved, but resolution of height position is low

Engineering Contradiction:
Improvealtitude accuracyVSAvoidheight position resolution
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system merges two different measurement approaches: using air pressure sensors for high-resolution height position changes and satellite systems for high-accuracy altitude determination. By combining these methods, the invention achieves both high resolution and high accuracy in altitude measurement.

Inventive Principle:
Principle #5Merging (Combining)

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

This approach significantly enhances the precision of slope determination and air resistance coefficient calculation, essential for optimizing bicycle performance and energy efficiency.

Implementation Method 1

Detecting an air pressure signal for an ambient pressure with at least one air pressure sensor on the bicycle while riding

Methodology Applied
Scientific EffectAir pressure detection:

Implementation Method 2

Determining or detecting a dynamic pressure value with at least one dynamic pressure sensor system on the bicycle while driving

Methodology Applied
Scientific EffectDynamic pressure:

Implementation Method 3

If the air pressure sensor to record the ambient pressure is arranged on one side of the two-wheeler component, the measurement result can be distorted by the Bernoulli effect

Methodology Applied
Scientific EffectBernoulli effect: Bernoulli Effect

Data Source

PatentEP3693257B1Method for detecting and evaluating sensor data and bicycle component
Publication Date: 2023.10.11 DT SWISS AG
  • EP3693257B1 patent drawingFigure 1~2
  • EP3693257B1 patent drawingFigure 3~5
  • EP3693257B1 patent drawingFigure 6~9

AI summary

Method for acquiring and evaluating sensor data while riding a bicycle (100) on a path (200) and two-wheeled component (1) comprising at least one air pressure sensor (20) for acquiring an air pressure signal (21) for an ambient pressure on the bicycle during riding, at least one dynamic pressure sensor (25) for determining at least one dynamic pressure value (26) on the bicycle during riding and a computing device (50) which is designed and configured to derive a corrected ambient pressure value (22) for the ambient pressure from the air pressure signal (21) on the bicycle during riding, taking into account the determined dynamic pressure value (26).