Bicycle Trainer Stator Torque Sensing for Accurate Power Measurement
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Solution Overview
Problem
Existing bicycle trainers lack accurate torque measurement, particularly in smart trainers, leading to inaccuracies in power calculation and a less realistic indoor riding experience.
Innovation Solution
A bicycle trainer system with a torque cell and strain gauges that directly measure torque through a stator of a generator resistance unit, using shear strain gauges to quantify mechanical deformations and provide accurate torque readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electric current based measurement is used to estimate torque in eddy current brake systems, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent replaces the electrical measurement method (current estimation) with a direct mechanical measurement method (strain gauges on the torque cell). The strain gauges physically measure the torque applied to the rotor, eliminating the need to infer torque from electrical current, thereby improving measurement precision while maintaining reasonable device complexity through the use of a dedicated torque measurement device.
2Device complexity
If electric current based measurement is used to estimate torque in generator resistance devices, then the device complexity is reduced, but the measurement precision deteriorates
Solution Approach 1:
The patent applies the same principle as above, replacing electrical current estimation with direct mechanical strain measurement using strain gauges mounted on the torque cell. This provides accurate torque measurement for generator resistance devices without significantly increasing device complexity.
3Measurement precision
If strain measurement devices are added to measure torque directly, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The torque cell with strain measurement devices serves multiple functions: it provides structural support for the stator, enables direct torque measurement through strain gauges, and facilitates accurate power calculation. By making the torque cell multi-functional, the patent improves measurement precision without proportionally increasing device complexity, as the same component performs multiple roles in the system.
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
The system provides accurate torque measurement, enhancing power calculation precision and offering a more realistic indoor riding experience by combining direct strain measurement with generator resistance systems.
Implementation Method 1
The strain measurement device includes a shear stain gauge
Implementation Method 2
Eddy current brakes create resistance when a conductive material in relative motion passes by a magnet
Data Source
AI summary
A bicycle trainer having a device for direct measurement of torque through a stator of a generator style resistance unit of a bicycle trainer is provided. The direct measurement may be accomplished through the disposition of strain gauges on a device positioned at the intersection of a stator and rigid frame attachment of the generator style resistance unit. The strain gauges may be disposed on radially extending spokes of the stator, or a carrier therefore.