Motor Drive Vibration Detection via Load Observer Torque Analysis
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Solution Overview
Problem
Existing systems for detecting vibrations in motor-driven mechanical systems are inefficient, requiring external vibration sensors and high data sampling rates, leading to increased costs and bandwidth usage, especially in complex control systems with multiple axes of motion.
Innovation Solution
A motor drive system that includes a load observer to estimate torque and determine frequency responses, allowing for the detection of vibrations by comparing measured magnitudes to set points, with status flags indicating excessive vibrations and alerting operators through a system controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external vibration sensors are used to detect vibrations, then vibration detection capability is improved, but device complexity and installation requirements increase
Solution Approach 1:
The motor drive system performs vibration detection using its own existing components (current sensors and control processor) without requiring external vibration sensors. The system serves itself by analyzing current feedback signals that already contain vibration information, eliminating the need for additional measurement devices and reducing system complexity.
Solution Approach 2:
The existing current feedback system, originally designed for motor control, is made multi-functional by also using it for vibration detection. The same current sensors and processor that control motor operation are simultaneously used to analyze vibration frequencies, reducing the need for dedicated vibration sensing components.
2Measurement precision
If high data sampling rates are used to detect vibrations, then measurement precision is improved, but bandwidth usage and data transmission requirements increase
Solution Approach 1:
The system extracts only the specific vibration frequency information from the current feedback signal using spectral analysis, rather than transmitting and processing the entire high-rate data stream. This allows accurate vibration detection at lower sampling rates by focusing computational resources on identifying specific frequency components associated with mechanical vibrations.
Solution Approach 2:
Instead of analyzing the complete frequency spectrum at high sampling rates, the system performs partial analysis by focusing on specific frequency ranges where mechanical vibrations typically occur. This selective approach reduces the computational and bandwidth requirements while maintaining effective vibration detection capability.
3Adaptability or versatility
If multiple controlled axes with multiple motor drives are used, then system functionality is improved, but data transmission bandwidth and complexity increase
Solution Approach 1:
The system merges the control and vibration detection functions into a single integrated processor within each motor drive. By combining these functions and using the existing control infrastructure for dual purposes, the system reduces the need for separate vibration detection hardware and minimizes data transmission requirements across multiple axes.
Data Source
AI summary
An improved system and method for analyzing motor performance to detect vibration of an electric machine controlled by a motor drive is disclosed. A load observer determines an estimated torque present as a load on the motor as a function of input signals corresponding to a desired torque to be generated by the motor and to a measured angular position of the motor during operation. The motor drive determines a frequency response of the estimated torque to identify at what magnitude and frequency any vibration components are present within the estimated torque signal. The motor drive compares the frequency response of the estimated torque signal to set points. If the measured magnitude of vibration at a particular frequency, as seen in the frequency response, exceeds a threshold set in one of the set points for that frequency, the motor drive generates an output signal indicting an excessive vibration is present.