Speed-Based Power Calculation for Bicycles
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Solution Overview
Problem
Existing bicycle power-sensing systems require expensive sensors like strain gauges or torque sensors and often rely on inaccurate speed-power lookup tables, necessitating a coast-down test to account for rolling resistance.
Innovation Solution
A system that calculates power based on speed measurements, using sensors to detect speed-related performance characteristics, such as inertia and resistive forces, without the need for expensive sensors, allowing for accurate power determination through evaluation of energy lost during deceleration periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive sensors like strain gauges or torque sensors are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical power sensing systems (strain gauges, torque sensors) with a computational approach that uses a processor to calculate power based on speed measurements and system characteristics. This substitution eliminates the need for complex mechanical sensors while maintaining power measurement capability through mathematical modeling and processing speed data.
Solution Approach 2:
The patent introduces speed measurements as an intermediary parameter to indirectly determine power. Instead of directly measuring power with complex sensors, the system measures speed and uses this intermediate measurement along with system inertia and resistance values to calculate power, simplifying the overall measurement system.
2Device complexity
If speed-power lookup tables are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent transitions from static lookup tables to a dynamic calculation system that continuously processes speed measurements, system inertia values, and resistance characteristics to compute power in real-time. This dynamic approach adapts to varying riding conditions and provides more accurate power calculations across different scenarios rather than relying on pre-computed static tables.
3Measurement precision
If coast-down tests are performed to account for rolling resistance, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent enables the system to automatically account for rolling resistance and other resistive forces through continuous processing of speed data and pre-determined system characteristics. The system self-calibrates by using the bicycle's own operational parameters (inertia, resistance values) without requiring external coast-down tests or manual calibration procedures, thereby eliminating time loss while maintaining accuracy.
4Device complexity
If simple speed sensors are used, then device complexity is reduced, but measurement precision deteriorates due to dynamic resistive forces
Solution Approach 1:
The patent compensates for the simplicity of speed sensors by dynamically adjusting calculation parameters including system inertia values, resistance characteristics, and speed measurements. The system processes multiple parameters (speed, acceleration, resistance values) through computational algorithms that adapt to changing riding conditions, thereby achieving high measurement precision despite using simple sensors.
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
Enables accurate power measurement without expensive sensors, eliminates the need for coast-down tests, and provides a compact, lightweight solution for both on-road and stationary bicycle training, accounting for dynamic resistive forces and temperature fluctuations.
Implementation Method 1
Evaluating changes in speed, such as deceleration, during the dead spot measurement periods allows for calculating energy lost as a function of energy dissipation during the dead spot measurement periods
Data Source
AI summary
A system for determining power expended by a bicyclist while riding a bicycle based on speed measurements or sensed-speed values. The system includes a sensing device arranged for detecting a speed-related value of the bicycle and a processor that communicates with the sensing device. The processor is configured to determine a change in the speed-related value and to determine a power value based on the change in the speed-related value.