Tactile-Optical Probe Position Detection Using Interferometry
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Solution Overview
Problem
Existing coordinate measuring machines face challenges in accurately and quickly detecting the relative or absolute position of a shaped probe element or mark, particularly in imaging directions and rotational degrees of freedom, with insufficient optical detection speed and accuracy.
Innovation Solution
A tactile-optical measuring method using a distance sensor, such as an interferometer or autofocus sensor, in combination with an optical lateral measuring method, to determine the position of a shaped probe element or mark in multiple directions, allowing for simultaneous evaluation of lateral deflection and absolute position, enabling precise three-dimensional positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fiber optic probes with one- or two-dimensional optical measuring systems are used, then the device complexity is reduced, but the measurement precision and detection speed in three-dimensional space are insufficient
Solution Approach 1:
The patent combines a two-dimensional optical measuring system (CCD/CMOS camera) with a one-dimensional distance sensor (interferometer or autofocus sensor) into an integrated sensor head. This merging allows simultaneous acquisition of lateral position (x, y) and depth position (z) of the probing element, achieving three-dimensional position detection with improved precision without proportionally increasing device complexity
Solution Approach 2:
The sensor head is designed to perform multiple measurement functions using a single integrated structure. The optical measuring system determines lateral deflection while the distance sensor determines axial position, enabling the same sensor assembly to capture complete three-dimensional position information and rotational degrees of freedom through coordinated operation of its components
2Productivity
If traditional optical sensors are used for position detection, then the device structure is simpler, but the detection speed and accuracy in imaging directions are insufficient
Solution Approach 1:
The patent replaces traditional mechanical position sensing methods with optical measurement principles. The optical measuring system uses image processing to detect lateral position with high speed and precision, while the distance sensor uses interferometric or autofocus methods to measure axial position rapidly, eliminating mechanical limitations and achieving superior detection performance
Solution Approach 2:
The patent transitions from two-dimensional optical sensing to three-dimensional position detection by adding the distance measurement dimension. The optical camera provides (x, y) coordinates while the distance sensor adds the (z) coordinate, creating complete spatial awareness and enabling accurate detection of probing element position and orientation in three-dimensional space
3Measurement precision
If rigid stylus with piezoelectric evaluation systems are used, then the measurement precision is improved, but the adaptability to different measurement configurations is reduced
Solution Approach 1:
The patent employs flexible connecting elements instead of rigid stylus structures. These flexible elements can adapt to different measurement configurations and probe geometries while the optical and distance sensors continuously track the probing element's position. This dynamic approach maintains measurement precision across varying configurations without requiring rigid, fixed-geometry systems
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
This approach enables rapid and precise detection of the relative or absolute position of a shaped probe element or mark, improving the accuracy and speed of coordinate measurement, particularly in determining three-dimensional positions and rotational movements.
Implementation Method 1
the position of a probing element extending from a probe extension, or at least a first mark associated with it extending from the probe extension, is determined in the X and Y directions of the coordinate measuring machine by means of a first sensor with an optically laterally measuring method
Implementation Method 2
the position of the probing element, or at least the first mark associated with it, is determined in at least one Z direction of the coordinate measuring machine perpendicular to the X and Y directions by means of at least one distance sensor
Implementation Method 3
A tactile-optical measuring method using a distance sensor, such as an interferometer or autofocus sensor, in combination with an optical lateral measuring method
Data Source
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AI summary
The invention relates to a method and arrangement for determining structures and/or geometry of a workpiece in a coordinate measuring machine by means of a tactile-optical measuring method, wherein the position of a shaped probe element is determined in at least one direction by means of a first sensor using an optically lateral measuring method, and the position of the shaped probe element is determined in at least one second direction using at least one distance sensor. In order to allow the error-free detection of the shaped probe element using the sensors, the invention proposes that at least one flexible connector element is used in a mounting for fastening the shaped probe element, permeated by the beam path of the first sensor in the beam direction, wherein the connecting element is transparent and/or is disposed severely out of focus with respect to the first sensor.