Servo System State-Change Detection via Integrated Gain
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Solution Overview
Problem
Conventional techniques fail to detect state changes in servo systems that involve no change in resonance frequency or a reduction in resonance peak value, such as when a coupling screw connecting a machine and a motor is loosened, as they rely on changes in resonance frequency or peak value for detection.
Innovation Solution
A state-change detecting device and method that measure gain-frequency characteristics and calculate a feature value as an integrated value of gains at individual frequencies within a specified range, allowing for the detection of state changes by comparing this value to past values, even if there is no change in resonance frequency or a reduction in resonance peak value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional detection methods relying on resonance frequency or peak value changes are used, then detection simplicity is maintained, but detection capability is insufficient for state changes involving no change in resonance frequency or reduction in resonance peak value
Solution Approach 1:
The patent changes the detection parameter from resonance frequency or peak value alone to an integrated value of gains across a frequency range. This parameter transformation enables detection of state changes that do not affect resonance frequency or peak value, such as coupling screw loosening, while maintaining a relatively simple detection framework.
2Reliability
If detection methods are expanded to cover all types of state changes, then detection comprehensiveness is improved, but false detection risk increases
Solution Approach 1:
The patent integrates gain values across a frequency range rather than relying on a single frequency point. This partial integration approach provides a more comprehensive view of system state changes while the comparison with predetermined thresholds prevents false detections by establishing clear decision boundaries.
Solution Approach 2:
The system compares the calculated integrated gain value with predetermined threshold values and provides feedback to determine whether a state change has occurred. This feedback mechanism enables accurate distinction between normal variations and actual state changes, reducing false detections while improving detection reliability.
Data Source
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AI summary
Provided is a state-change detecting device that is capable of detecting a state change involving no change in the resonance frequency or a state change involving a reduction in the resonance peak value in a servo system. A state-change detecting device according to the present invention is provided with: a calculation means that measures gain-frequency characteristics of a servo system being evaluated and that calculates, as a feature of the servo system being evaluated, a value correlated with an integrated value of gains at individual frequencies within a frequency range being evaluated in the measured gain-frequency characteristics; and a determination means that determines whether or not the state of the servo system being evaluated has changed by comparing the feature calculated by the calculation means with the same feature in the past for the servo system being evaluated.