Motor Notch Frequency Forecasting for Resonance Shift Detection
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Solution Overview
Problem
Conventional motor control devices fail to effectively detect and prevent abnormal operations caused by changes in mechanical resonant frequency, leading to unnecessary equipment downtime and maintenance.
Innovation Solution
A motor control device that includes a notch filter and a change forecaster to predict when the notch frequency will fall out of a specific range, allowing for early recognition of abnormal operation occurrences and preventing oscillations in the feedback control system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional motor control devices suppress mechanical resonant vibration without detecting frequency changes, then vibration suppression is maintained, but abnormal operations go undetected leading to unnecessary equipment downtime
Solution Approach 1:
The system performs preliminary detection of mechanical resonant frequency changes and forecasts future frequency trends before abnormal operations occur. By monitoring frequency shifts in advance and predicting when they will exceed thresholds, the system can prepare appropriate responses, avoiding unnecessary equipment shutdowns while maintaining vibration suppression effectiveness.
Solution Approach 2:
The system continuously monitors mechanical resonant frequency and provides feedback on frequency changes and predicted abnormal operations. This feedback mechanism allows the system to distinguish between normal frequency variations and abnormal conditions requiring intervention, reducing false alarms and unnecessary downtime while maintaining reliable vibration suppression.
2Manufacturing precision
If the notch filter frequency is continuously adjusted to track mechanical resonant frequency, then vibration suppression effectiveness is improved, but the system cannot distinguish normal changes from abnormal operations
Solution Approach 1:
The system segments the frequency change monitoring into two distinct functions: one for continuous notch filter frequency adjustment to maintain vibration suppression, and another for detecting abnormal operations by comparing frequency changes against predicted trends and thresholds. This segmentation allows the system to maintain precision while improving abnormal operation detection capability.
Solution Approach 2:
The system introduces an intermediary forecasting mechanism that predicts future mechanical resonant frequency values based on historical data. This intermediary layer acts as a reference against which actual frequency measurements are compared, enabling the system to distinguish between normal frequency drift and abnormal operations requiring intervention.
3Difficulty of detecting and measuring
If the system monitors mechanical resonant frequency changes to detect abnormal operations, then detection capability is improved, but false alarms increase causing unnecessary maintenance
Solution Approach 1:
The system performs preliminary forecasting of mechanical resonant frequency trends before making abnormal operation determinations. By predicting future frequency values and comparing actual measurements against these predictions, the system reduces false alarms and unnecessary maintenance while maintaining high detection capability for genuine abnormal operations.
Solution Approach 2:
The system uses feedback from historical frequency data to continuously refine its abnormal operation detection thresholds and forecasting models. This adaptive feedback mechanism reduces false alarms by learning from past operations while maintaining sensitivity to genuine abnormal conditions, thereby reducing unnecessary maintenance frequency.
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
Enables users to easily recognize signs of abnormal operation due to changes in mechanical resonant frequency, reducing equipment downtime and maintenance needs by predicting when the notch frequency will exceed safe limits.
Implementation Method 1
a notch filter configured to remove a frequency component in the torque command value
Implementation Method 2
a feedback controller configured to feedback-control to make the motor speed follow the speed command
Data Source
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AI summary
The invention provides a motor control device configured to feedback-control state quantity of a motor or a load, the device including a first notch filter disposed inside a feedback control system and configured to change a frequency component to be removed, a first notch controller configured to change a first notch frequency as a center frequency of the first notch filter, and a change forecaster configured to calculate to output, in accordance with the first notch frequency at each of a plurality of past times, at least one of a forecast value of the notch frequency at a specific future time, a forecast value of elapsed time from current time until the notch frequency is to become out of a specific frequency range, and a forecast value of time when the notch frequency is to become out of the specific frequency range.