Noncontact Sensor Calibration Using Rotating Multi-Sphere Artifact
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Solution Overview
Problem
Analytical gear testing machines with limited axes, such as those with only one rotational axis, are unable to adequately re-position non-contact sensors like lasers for accurate calibration, restricting the collection of sufficient data for precise probe calibration parameters.
Innovation Solution
A calibration artifact with multiple, rigidly fixed calibration spheres arranged at different radial and axial positions on a rotatable disk, allowing the spheres to pass through the sensor's field of view as the machine rotates, enabling accurate calibration without the need for three-dimensional positioning of the probe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single calibration sphere is used with limited axis movement, then the calibration process can be performed on machines with only one rotational axis, but the probe cannot be adequately re-positioned to collect sufficient data for accurate calibration parameters
Solution Approach 1:
The calibration artifact is segmented into multiple calibration spheres (at least three) positioned at different radial and axial locations. This segmentation allows the limited single-axis rotation to capture multiple distinct calibration points, providing sufficient data for accurate probe calibration parameters despite the machine's restricted positioning capability
Solution Approach 2:
The calibration spheres are arranged in three-dimensional space at different radial distances and axial positions from the rotation axis. This multi-dimensional arrangement ensures that rotation about a single axis produces varied sensor readings across multiple spatial dimensions, enabling accurate calibration without requiring three-dimensional probe positioning
2Measurement precision
If multiple calibration spheres are positioned at different radial and axial positions, then sufficient data can be collected for accurate calibration, but the calibration artifact becomes more complex
Solution Approach 1:
The calibration artifact serves multiple functions simultaneously: it provides multiple calibration spheres at different positions, defines radial and axial reference dimensions, and enables calibration on machines with limited axes. This multi-functionality reduces the need for separate calibration artifacts or complex positioning mechanisms
Solution Approach 2:
Multiple calibration spheres are rigidly combined into a single artifact body with defined geometric relationships. This merging creates a unified calibration reference that can be measured in various configurations during single-axis rotation, simplifying the overall calibration process while maintaining measurement precision
Data Source
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AI summary
A probe calibration method and calibration artifact (30, 70) whereby calibration can be performed without the use of machine axes capable of three dimensional positioning of a probe relative to a calibration sphere (40). The method includes a plurality of calibration spheres fixed in relation to one another via a rigid structure comprising a calibration artifact body (30, 70). The spheres are mounted such that each will be sensed by the probe at some position of a machine axis (W, N). In other words, the spheres lie in the region swept out by the sensor field of view (8, 78) over the movement of the machine axis. The calibration spheres are located at known positions (A, B, C) and the calibration artifact body is designed such that it may be mounted in a known location in place of a work piece.