Feed Axis Abnormality Diagnosis Using Servo Frequency Analysis
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Solution Overview
Problem
Current diagnostic methods for feed axes in machine tools, such as those using ball screws, require additional sensors to detect abnormalities like abrasion and damage, increasing costs and breakdown risks, and fail to detect mild damage before significant degradation occurs.
Innovation Solution
A method and device that perform abnormality diagnosis of feed axes, including ball screws, bearings, and linear guides, by calculating a feed velocity to detect damage frequencies through frequency analysis of servo information without additional sensors, using existing servo motor control data to determine the presence of damage peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are added to detect abnormalities in the feed axis, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The servo motor's existing control system performs self-diagnosis by analyzing its own servo information (current, position, speed data) to detect abnormalities in the feed axis components. The system uses its inherent operational data to identify vibrations and anomalies without requiring external diagnostic sensors, enabling the system to monitor its own health through standard control operations.
Solution Approach 2:
The servo motor's control system serves multiple functions: it controls the motor operation and simultaneously performs abnormality diagnosis of the feed axis. The existing servo information processing infrastructure is utilized for both motion control and diagnostic purposes, eliminating the need for separate dedicated diagnostic hardware.
2Measurement precision
If additional sensors are added to detect abnormalities in the feed axis, then measurement precision is improved, but reliability deteriorates due to increased breakdown risk
Solution Approach 1:
The servo motor's existing control system performs self-diagnosis by analyzing its own servo information (current, position, speed data) to detect abnormalities in the feed axis components. The system uses its inherent operational data to identify vibrations and anomalies without requiring external diagnostic sensors, enabling the system to monitor its own health through standard control operations.
3Device complexity
If frequency analysis is performed on servo information without additional sensors, then device complexity is reduced, but measurement precision deteriorates due to inability to detect mild damage
Solution Approach 1:
The method detects abnormalities by analyzing vibrations in the servo information that occur when damaged components (ball screw, bearing, linear guide) rotate or move. The frequency analysis identifies characteristic vibration frequencies corresponding to different components, enabling detection of mild damage through subtle vibration patterns in the existing servo control data.
Solution Approach 2:
The system performs frequency analysis on servo information at specific operating conditions (particularly at speeds where damage frequencies are amplified) to enhance detection sensitivity. By focusing analysis on critical operational parameters and frequency ranges, the system achieves high detection precision for mild damage using only existing sensors.
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
This approach allows for low-cost abnormality diagnosis of feed axes without additional sensors, enabling early detection of mild damage and preventing costly failures in machine tools.
Implementation Method 1
a frequency analysis unit configured to perform a frequency analysis on the servo information
Implementation Method 2
a vibration detection unit configured to detect a vibration of the feed axis
Data Source
AI summary
It is an object to perform an abnormality diagnosis for a feed axis without additionally adding a sensor or the like. A frequency characteristic of a feed axis and a damage frequency that occurs when the feed axis that has been damaged performs an axis operation are obtained, a frequency where a gain is maximized in the obtained frequency characteristic is calculated, and a feed velocity where the frequency matches the damage frequency is calculated. An axis operation is performed on the feed axis with the calculated feed velocity, and a frequency analysis is performed on servo information regarding a control of a servo motor during the axis operation. Then, the presence and absence of a peak of the damage frequency is confirmed from a result of the frequency analysis, and when the peak is present, it is determined that it is abnormal.