Inductive Stylus Position Sensing for Precise CMM Deflection Detection
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Solution Overview
Problem
Inductive sensing configurations in coordinate measuring machines (CMMs) face issues such as signal non-linearities, position offsets, signal drift due to environmental factors, and signal noise, which hinder precise measurement of small deflections.
Innovation Solution
A measuring probe with a stylus suspension portion, stylus position detection portion, and signal processing circuitry, utilizing a field generating coil and sensing coils to generate and detect magnetic flux, and process signals for accurate axial and rotary position measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inductive sensing configurations are used for position detection, then measurement capability is provided, but signal non-linearities and position offsets occur
Solution Approach 1:
The patent applies parameter changes by utilizing the non-linear relationship between disruptor position and induced voltage as a distinctive feature. Instead of attempting to linearize the response, the system measures the actual non-linear voltage output and uses it to determine position through comparison with predetermined voltage patterns, thereby converting the non-linearity from a defect into a useful characteristic for precise position detection.
2Measurement precision
If inductive sensing configurations are used for position detection, then measurement capability is provided, but signal drift due to environmental effects occurs
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual voltage induced in the sensing coil and comparing it with predetermined voltage patterns stored in memory. This comparison allows the system to compensate for environmental drift and other variations by referencing the established patterns, thereby maintaining reliable position detection despite changing conditions.
Solution Approach 2:
The patent applies preliminary action by pre-determining and storing the voltage induction patterns for various disruptor positions in memory before actual measurement takes place. These predetermined patterns serve as reference data that enable the system to compensate for environmental effects and maintain signal stability during operation.
3Measurement precision
If inductive sensing configurations are used for position detection, then measurement capability is provided, but signal noise increases
Solution Approach 1:
The patent implements feedback by continuously monitoring the actual voltage induced in the sensing coil and comparing it with predetermined voltage patterns stored in memory. This comparison allows the system to compensate for environmental drift and other variations by referencing the established patterns, thereby maintaining reliable position detection despite changing conditions.
4Measurement precision
If multiple coil configurations are used to improve measurement accuracy, then detection precision is enhanced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the sensing function into multiple independent coil configurations, each responsible for detecting specific motion parameters (axial motion, rotary motion, etc.). This segmentation allows the system to process complex three-dimensional motion by breaking it down into separate detectable components, thereby enhancing measurement precision while maintaining manageable system complexity.
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 solution provides improved signal processing and control circuitry to enhance the accuracy and precision of CMM measurements by minimizing signal variations and environmental effects, enabling precise detection of small deflections.
Implementation Method 1
The field generating coil configuration is configured to generate a changing magnetic flux generally along the axial direction in the disruptor motion volume in response to a coil drive signal
Implementation Method 2
The sensing coil configuration comprises a plurality of sensing coils... configured to provide signals comprising respective signal components
Data Source
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AI summary
A measuring probe for a coordinate measuring machine is provided. The measuring probe includes a stylus position detection portion with a sensing coil configuration comprising a plurality of sensing coils. Different couplable coil portions (e.g., which each at least partially surround a central axis) are provided that may be connected (e.g., individually and/or in series as part of an axial, rotary or normalization sensing coil of the plurality of sensing coils) as part of different stylus position detection configurations. For example, a first couplable coil portion may be connected to provide signals as received by signal processing and control circuitry in a first stylus position detection configuration, and may not be connected to provide signals in a second stylus position detection configuration. A second couplable coil portion may be connected to provide signals received by the signal processing and control circuitry in at least a second stylus position detection configuration.