Machine Tool Error Measurement With Disturbance Index Screening
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Solution Overview
Problem
Existing machine tool error measurement methods fail to accurately measure errors in machine tools due to disturbances from foreign matter, especially when measuring complex shapes, leading to degraded processing accuracy.
Innovation Solution
An error measurement method for machine tools that includes error value acquisition, disturbance index calculation, and threshold determination, using a sensor to detect positions of multiple targets on a masterwork, calculating disturbance indices based on error values, and re-acquiring measurements if disturbance exceeds a threshold, allowing for automatic detection and mitigation of measurement disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a touch probe measures the position of a target on a masterwork, then the measurement result can be used for compensation control, but foreign matter attached to the masterwork may cause disturbance in the measurement result
Solution Approach 1:
The patent implements a feedback mechanism by calculating a disturbance index value from measurement results and comparing it with a threshold. When the disturbance index exceeds the threshold, the system identifies the measurement as disturbed and requests re-measurement, thereby eliminating the harmful effect of foreign matter on measurement reliability
Solution Approach 2:
The patent replaces direct reliance on mechanical measurement accuracy with an automated computational system that calculates disturbance index values and makes automated decisions about measurement validity, substituting mechanical precision requirements with intelligent data processing
2Productivity
If compensation control is performed with compensation parameter calculated from disturbed measurement result, then the control process continues, but processing accuracy is degraded
Solution Approach 1:
The patent performs preliminary detection of measurement disturbance by calculating the disturbance index value before using the measurement result for compensation control. This preliminary action prevents degraded processing accuracy by identifying disturbed measurements in advance, while maintaining productivity through automated decision-making
3Measurement precision
If the position of the target is measured with the touch probe, then error values can be acquired for compensation control, but the measurement may be disturbed by foreign matter on the masterwork
Solution Approach 1:
The system establishes a feedback loop where measurement results are evaluated by calculating disturbance index values, and based on this evaluation, the system determines whether to accept or reject measurements and request re-measurements, thereby maintaining measurement precision while ensuring reliability
Data Source
AI summary
An error measurement method for a machine tool measures an error in a machine tool that includes two or more translational axes, a table, and a spindle head. The error measurement method includes installing a masterwork having a plurality of targets on the table and detecting a position of each of the targets using a sensor mounted to the spindle head to acquire a measured value regarding the position of each of the targets and to acquire an error value regarding the position of each of the targets using each of the acquired measured values and a preliminarily acquired calibration value regarding the position of each of the targets. The error measurement method further includes calculating at least one disturbance index value indicative of a degree of disturbance in the measurement for each of the targets, and determining whether the disturbance index value exceeds a preliminarily set threshold.