Distance Sensor Strain Feedback for Narrow Probe Arm Accuracy
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Solution Overview
Problem
Tactile and optical distance sensors in coordinate measuring machines face challenges with long, narrow constructions that are prone to static and dynamic deformations, leading to sensitivity issues with force fluctuations and vibrations, resulting in measurement errors, especially in complex and hard-to-access workpiece surfaces.
Innovation Solution
Incorporating a strain sensor, such as a fiber Bragg grating, to capture and correct for deformations in the measurement arm, allowing for a smaller diameter and improved access while maintaining measurement accuracy, and integrating this sensor within the housing for effective bending moment detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the measurement arm is made long and narrow to access hard-to-reach measurement sites, then accessibility to measurement sites is improved, but static and dynamic deformations increase leading to measurement errors
Solution Approach 1:
A strain sensor (fiber Bragg grating) is integrated into the measurement arm to detect deformations in real-time. The measured deformation values are fed back to the evaluation device, which compensates for these deformations in the measurement results, thereby maintaining measurement accuracy despite the long and narrow construction of the measurement arm
Solution Approach 2:
The patent replaces purely mechanical rigidity requirements with an optical sensing system (fiber Bragg grating) that can detect and compensate for mechanical deformations. This allows the measurement arm to be made lighter and more flexible while maintaining measurement accuracy through electronic compensation rather than relying solely on mechanical stiffness
2Ease of operation
If the measurement arm is made long and narrow, then accessibility to measurement sites is improved, but sensitivity to force fluctuations and vibrations increases
Solution Approach 1:
The strain sensor provides continuous feedback on the actual deformation state of the measurement arm caused by vibrations and force fluctuations. The evaluation device uses this feedback to distinguish between intentional probe deflections (measurement signals) and unwanted arm deformations (vibration noise), thereby filtering out vibration-induced measurement errors
Solution Approach 2:
The patent converts the harmful effect of vibrations and force fluctuations into useful information by using the strain sensor to detect these deformations. The detected deformation patterns are then used by the evaluation device to compensate for their negative effects, transforming what was previously a source of measurement error into a correctable parameter
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 strain sensor enhances the tolerance to natural vibrations and bending, improving measurement accuracy by correlating strain sensor values with probe element deflection values, reducing measurement errors and preventing damage to the system or workpiece.
Implementation Method 1
a strain sensor is located in the region of the measurement arm extending through the elongate portion or at an adjacent region directly adjoining said region, the strain sensor having a fiber Bragg grating
Data Source
AI summary
A tactile and/or optical distance sensor includes a housing, which has at least one elongate portion, a measurement arm, which is arranged in the housing, at least partially extends through the elongate portion and has a tactile and/or an optical probe element at one end, a transducer, which is configured to capture a position of the tactile probe element or a signal of the optical probe element and to generate associated probe element measurement signals, and an advance unit, with which the housing is linearly dis-placeable along an advance direction. A strain sensor is located in the region of the measurement arm extending through the elongate portion or at an adjacent region directly adjoining said region. In addition, a system for measuring the roughness of a surface of a workpiece and a method for calibrating a distance sensor or a system are provided.