Analogue Contact Probe Calibration Across Multiple Orientations
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Solution Overview
Problem
Current coordinate positioning systems require extensive calibration for each orientation of contact probes, especially when mounted on continuous heads, making the process time-consuming and impractical due to the near infinite number of possible orientations.
Innovation Solution
A method for calibrating analogue contact probes by determining a gain variation model that accounts for the variation in probe signal gain based on orientation, allowing for the conversion of probe signals into spatial measurements across multiple orientations using a consolidated probe signal conversion model and gain variation correction factors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed for each orientation of the contact probe, then measurement accuracy is improved, but calibration time increases significantly
Solution Approach 1:
The patent combines calibration data from multiple probe orientations into a single consolidated calibration model. Instead of performing separate calibrations for each orientation, the system collects measurement data at various orientations and merges them into one comprehensive calibration dataset, thereby reducing total calibration time while maintaining measurement accuracy across all orientations.
Solution Approach 2:
The patent creates a universal calibration model that functions across multiple probe orientations simultaneously. The single calibration model is designed to be orientation-independent, allowing it to accurately convert probe signals to spatial measurements regardless of the probe's orientation, eliminating the need for orientation-specific calibration procedures.
2Loss of time
If a single probe signal conversion model is used for all orientations, then calibration time is reduced, but measurement accuracy deteriorates due to orientation-dependent signal variations
Solution Approach 1:
The patent introduces orientation compensation parameters that adjust the probe signal conversion based on the actual probe orientation during measurement. By dynamically modifying conversion parameters according to orientation, the system maintains high measurement accuracy across all orientations while using a single consolidated calibration model, thus avoiding the time penalty of multiple calibrations.
3Measurement precision
If calibration data is collected at multiple orientations, then orientation-dependent errors are captured, but the complexity of the calibration process increases
Solution Approach 1:
The patent uses a standardized data collection template that can be replicated across different probe orientations. By copying the same measurement procedure and data structure for each orientation, the system simplifies the overall calibration process while still capturing orientation-dependent characteristics. This standardized approach reduces the perceived complexity despite collecting data at multiple orientations.
Data Source
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AI summary
A method of calibrating a contact probe having a deflectable stylus and configured to provide at least one signal which is indicative of the extent of deflection of the stylus, the contact probe being mounted on a coordinate positioning machine which facilitates reorientation of the contact probe about at least one axis. The method comprises: taking measurement data obtained with the contact probe positioned at a plurality of different orientations about the at least one axis; and determining from the measurement data at least one gain variation model which models any apparent variation in the gain of the at least one probe signal dependent on the orientation of the contact probe about the at least one axis.