Coordinate Measuring Probe Error Compensation Without Bandwidth Loss
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Solution Overview
Problem
Coordinate measuring machines face reduced measurement accuracy due to mechanical vibrations of the stylus, which are typically mitigated by low-pass filtering, resulting in reduced measurement bandwidth and scanning speed.
Innovation Solution
A method and measuring machine that utilize a state observer, preferably a Kalman filter, to estimate and compensate for measurement errors caused by stylus vibrations by acquiring signals related to acceleration and relative displacement, maintaining high measurement bandwidth and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If low-pass filter is used to limit mechanical vibrations of the stylus, then measurement accuracy is improved, but measurement bandwidth is reduced
Solution Approach 1:
The patent replaces the mechanical signal filtering approach (low-pass filter) with a mathematical modeling and estimation approach (state observer/Kalman filter). Instead of physically filtering the measurement signals to reduce vibrations, the system uses a dynamic model of the probe to estimate and compensate for vibrational effects computationally, thereby maintaining full measurement bandwidth while achieving vibration compensation.
Solution Approach 2:
The patent introduces a state observer as an intermediary computational layer between the raw measurement signals and the final compensated measurements. This observer acts as a mediator that processes the raw signals through a mathematical model to extract accurate measurement information while filtering out vibrational noise, avoiding the need for direct signal filtering that would lose bandwidth.
2Measurement precision
If low-pass filter is used to reduce stylus vibration effects, then measurement accuracy is improved, but scanning speed is reduced
Solution Approach 1:
The patent replaces the mechanical signal filtering approach (low-pass filter) with a mathematical modeling and estimation approach (state observer/Kalman filter). Instead of physically filtering the measurement signals to reduce vibrations, the system uses a dynamic model of the probe to estimate and compensate for vibrational effects computationally, thereby maintaining full measurement bandwidth while achieving vibration compensation.
Solution Approach 2:
The patent enables continuous high-speed scanning without interruption or signal loss by using real-time state estimation. The mathematical model continuously processes incoming measurement signals to provide compensated outputs, allowing the scanning operation to proceed at full speed without the bandwidth limitations imposed by traditional filtering methods.
3Measurement precision
If low-pass filter is used to compensate for stylus deformation, then measurement accuracy is improved, but measurement bandwidth is reduced
Solution Approach 1:
The patent replaces the mechanical signal filtering approach (low-pass filter) with a mathematical modeling and estimation approach (state observer/Kalman filter). Instead of physically filtering the measurement signals to reduce vibrations, the system uses a dynamic model of the probe to estimate and compensate for vibrational effects computationally, thereby maintaining full measurement bandwidth while achieving vibration compensation.
Solution Approach 2:
The patent changes the approach from filtering signals in the frequency domain (low-pass filter) to estimating system state in the time domain using a dynamic model. By changing from a passive filtering approach to an active estimation approach with a mathematical model of probe dynamics, the system achieves deformation compensation without sacrificing bandwidth.
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
Enables fast and accurate measurements by effectively compensating for stylus deformation, allowing high scanning speed and density of measurement points without reducing measurement bandwidth.
Implementation Method 1
estimating a deformation, by compensating for measurement errors due to the mechanical vibrations of the stylus, of the probe by means of a state observer, which uses said mathematical model and receives as input the first signal and the second signal
Data Source
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AI summary
A method for the compensation of measurement errors of a measuring machine (1) comprising a probe (13) provided with a first body (14) and a mobile part comprising a second body (16), which is attached to the first body (14) and is movable with respect to the first body (14), and a stylus (18) having at least one tip (19) at one end configured to cooperate with a workpiece (20); the method comprising the steps of: - providing a mathematical model of the probe (13); - acquiring a first signal (P̈1) related to the acceleration of the first body (14); - acquiring a second signal (P0-P1) related to the relative displacement between the first and second bodies (14, 16); and - estimating a deformation of the probe (13) by means of a state observer (25), which uses said mathematical model and receives as input the first signal (P̈1) and the second signal (P0-P1) .