Surface Texture Measuring Instrument Deformation Correction
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Solution Overview
Problem
Traditional surface texture measuring instruments face challenges in achieving high-speed and high-accuracy scanning measurements due to deformation errors caused by acceleration, particularly when measuring large objects, as existing correction methods suffer from low resolution and the impracticality of providing acceleration sensors for each axis.
Innovation Solution
A surface texture measuring instrument that includes a scanning probe with a detection sensor, a scanning vector commander, a drive mechanism, and a correction-calculating unit using a nominal model to estimate the movement condition and calculate correction amounts for deformation errors, allowing for accurate measurement data synthesis without relying on actual measured data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-speed scanning measurement is conducted, then productivity is improved, but measurement precision deteriorates due to deformation errors caused by acceleration
Solution Approach 1:
The patent pre-calculates and stores correction values for drive mechanism deformation at various acceleration levels before actual measurement. During high-speed scanning, the system retrieves and applies the appropriate correction value based on the current acceleration, eliminating the need for real-time complex calculations and enabling both high speed and high precision measurement through advance preparation
Solution Approach 2:
The system continuously monitors the actual acceleration of the drive mechanism during scanning and dynamically applies correction values from the pre-calculated table. This feedback mechanism ensures that measurement errors caused by acceleration-induced deformation are compensated in real-time, maintaining measurement precision even at high scanning speeds
2Measurement precision
If correction values are calculated in real-time during measurement, then measurement precision is improved, but loss of time increases due to complex calculations
Solution Approach 1:
The patent pre-calculates correction values for various acceleration levels and stores them in a table before actual measurement begins. During measurement, the system simply retrieves the appropriate correction value from the pre-computed table based on the current acceleration, avoiding time-consuming real-time calculations while maintaining high correction accuracy
Solution Approach 2:
Instead of performing complex real-time calculations, the system creates a lookup table containing pre-calculated correction values that represent the ideal correction data. During measurement, the system copies the appropriate correction value from this table based on the current operating conditions, significantly reducing computation time while preserving accuracy
3Measurement precision
If acceleration sensors are provided for each axis to detect actual acceleration, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical approach of using physical acceleration sensors with each axis with a computational approach. The system calculates acceleration by differentiating position data obtained from the drive mechanism's position detection, then uses this calculated acceleration to retrieve appropriate correction values from pre-computed tables, eliminating the need for additional sensors and reducing system complexity
Solution Approach 2:
The patent introduces position detection data from the drive mechanism as an intermediary to obtain acceleration information. Instead of directly measuring acceleration with sensors, the system uses position data as a mediator, differentiating it to derive acceleration, which then serves as the key to retrieve correction values from the pre-calculated table
Data Source
AI summary
A surface texture measuring instrument includes: a movement-estimating unit for estimating a movement condition of a drive mechanism based on a scanning vector command issued by a scanning vector commander to calculate an estimated operation state quantity; and a correction-calculating unit for correcting a detection value of a drive sensor in accordance with the estimated operation state quantity calculated by the movement-estimating unit. The movement-estimating unit includes: a nominal-model setting unit in which a nominal model representing signal transfer function of the scanning vector command from the issuance of the scanning vector command to a reflection on a movement position of the scanning probe is stored. The correction-calculating unit includes a correction-amount calculating unit that calculates a correction amount for correcting a measurement error generated on account of deformation during the drive of the drive mechanism based on the estimated operation state quantity; and a measurement data synthesizing unit that synthesizes the detection value of the drive sensor and a detection sensor and the correction amount calculated by the correction-amount calculating unit to acquire a measurement data.