CNC Grinding Spindle Error Compensation With In-Situ Vision Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for compensating spindle rotation errors in CNC grinding machines are inadequate, particularly in real-time in-situ measurement and compensation of axial and radial errors, leading to machining accuracy issues due to measurement lag and complexity in existing methods.
Innovation Solution
An evolutionary compensation method based on timing in-situ measurement, where a spindle rotation error measuring device is used to determine feature points on the spindle, acquire and process trajectory images, establish a compensation model, and continuously update it to improve accuracy, allowing for real-time compensation of axial and radial errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If displacement sensors are arranged in the axial and radial directions of the spindle to measure rotation error indirectly, then measurement capability is improved, but device complexity and difficulty of installation increase
Solution Approach 1:
The patent replaces the mechanical displacement sensor measurement system with an optical machine vision system. The machine vision measuring device captures trajectory images of feature points on the spindle, and image processing algorithms calculate rotation errors, eliminating the need for complex mechanical sensor arrangements while achieving high measurement precision.
Solution Approach 2:
The patent uses machine vision to create a digital copy of the spindle's rotational trajectory by capturing images of feature points. This optical copy allows for precise measurement of rotation errors through image processing without requiring physical contact sensors, thereby simplifying the measurement system.
2Measurement precision
If machine vision is used to acquire and process trajectory images of feature points, then measurement capability is improved, but processing complexity and measurement lag increase
Solution Approach 1:
The patent applies preliminary action by pre-establishing the compensation model before actual machining operations. The model is trained offline using collected trajectory image data and rotation error measurements, so that during real-time operation, only simple inference is needed rather than full processing, significantly reducing measurement and compensation lag.
Solution Approach 2:
The patent implements feedback by continuously monitoring spindle rotation errors through machine vision measurement and using this information to dynamically adjust and optimize the compensation model. The measured rotation errors feed back into the system to improve compensation accuracy over time, creating a closed-loop control system that reduces lag through adaptive optimization.
3Ease of operation
If static rotation accuracy is used as the measurement index, then measurement simplicity is maintained, but machining accuracy for precision and ultra-precision parts deteriorates
Solution Approach 1:
The patent transitions from static rotation accuracy measurement to dynamic measurement during actual spindle operation. The machine vision system captures trajectory images while the spindle is rotating, and the compensation model processes this dynamic data to provide real-time compensation, ensuring high machining accuracy for precision and ultra-precision parts while maintaining operational simplicity.
Data Source
AI summary
An evolutionary compensation method for a spindle rotation error of a CNC grinding machine is provided. Feature points are determined at an edge of a central hole of a spindle of a CNC grinding machine, and a spindle rotation error in-situ measuring device is fixed on the grinding machine and aligned with the edge of the central hole; a trajectory image of the feature points is acquired by using the measuring device; a measured value of the spindle rotation error is obtained according to the trajectory image; features of the spindle rotation error are fused with the measured value of the spindle rotation error, a spindle rotation error compensation model is established, to output a spindle rotation error compensation value, thereby compensating the spindle rotation error. By continuously calibrating the error model using the measured value, accuracy of the error model has been continuously optimized.