Precision Torque Device Using Retroreflective Ball and Laser Interferometry
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Solution Overview
Problem
Existing methods for generating and measuring torques suffer from low accuracy due to uncertainties in the radius of force application and require additional components or equipment modifications, limiting the precision of torque generation and measurement.
Innovation Solution
A device utilizing a rotatably mounted beam with a precisely known spherical running weight, where the ball acts as a retroreflector or mirror for non-contact position measurement, combined with backlash-free bearings and an electrodynamic actuator, allowing for high-resolution torque generation and measurement by detecting changes in the ball's position relative to the fulcrum, without direct contact during measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If masses are suspended from a rotatable beam at uniform distances, then torque can be generated discretely by adjusting imbalance, but the radius at which forces act cannot be precisely known, limiting measurement accuracy
Solution Approach 1:
The patent replaces mechanical contact-based positioning with optical measurement. A laser beam and retroreflector system is used to non-contactly measure the position of the spherical mass on the beam with high precision, eliminating the need for complex mechanical positioning mechanisms while achieving superior measurement accuracy.
Solution Approach 2:
The patent introduces a retroreflector as an intermediary element attached to the spherical mass. This retroreflector works with the laser beam to enable precise position measurement without direct contact between the measurement system and the mass, allowing accurate determination of the force application radius.
2Measurement precision
If sliding weights are used to generate torque, then device structure is simple, but measurement accuracy is low because not only the mass of the sliding weight but also other components contribute to torque generation
Solution Approach 1:
The patent extracts the measurement function from the mechanical structure by using optical measurement. The laser interferometer measures the position of the spherical mass independently of the mechanical components, allowing accurate determination of torque without being affected by uncertainties in component masses and dimensions.
Solution Approach 2:
The patent replaces mechanical contact-based position sensing with optical interferometry. This substitution eliminates the need for complex mechanical positioning mechanisms and allows for high-precision measurement of the mass position, thereby achieving accurate torque generation and measurement.
3Measurement precision
If non-contact length measurement is used to measure ball position, then measurement accuracy is high, but the ball must have specific properties (retroreflector or reflective surface)
Solution Approach 1:
The spherical mass serves multiple functions: it is the weighting element that generates torque, the object whose position is measured, and the carrier of the retroreflector or reflective surface. This multi-functionality eliminates the need for separate measurement markers or retroreflectors, simplifying the overall device structure while maintaining high measurement accuracy.
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 the generation and determination of high-precision torques with selectable values and sequences, achieving resolutions not previously attainable, suitable for metrological applications and calibration laboratories.
Implementation Method 1
The ball (1) acts as a retroreflector if the material has a suitable refractive index, or as a mirror if it has a reflective surface.
Implementation Method 2
The ball (1) acts as a retroreflector if the material has a suitable refractive index, or as a mirror if it has a reflective surface.
Implementation Method 3
The position of the ball (1) is continuously measured with high accuracy by a suitable, non-contact length measuring unit (4)
Implementation Method 4
a ball (1) of a very precisely known weight is arranged on the beam (2)
Data Source
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AI summary
The aim of the invention is to provide a device for producing highly precise torques and a method for determining said torques, by means of which device both continuous torque curves and torques in discrete steps can be produced with high resolution and high accuracy. The device according to the invention comprises a rotatably mounted guiding beam (2), on which a very dimensionally stable sphere (1) having a very exactly known weight is arranged. The displacement of the center of mass of the sphere (1) is continuously or discontinuously measured with high accuracy by means of a suitable length-measuring unit (4) that operates without contact. Because of the high resolution and accuracy of the length measurement in combination with the knowledge of the mass of the sphere, torques can be produced and determined with previously unachieved precision.