Servo Motor Controller Abnormality Detection
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Solution Overview
Problem
Existing servo motor controllers cannot detect abnormalities in incremental encoders prior to establishing the absolute position, leading to potential improper driving of servo motors due to undetected issues in the position and magnetic pole detection systems.
Innovation Solution
A servo motor controller that includes a position detection part, a magnetic pole detection part, and a pole position calculation part, capable of determining abnormality by comparing the magnetic pole positions obtained from both parts with a predetermined threshold before establishing the absolute position, and generating an alarm to stop the servo motor if abnormalities are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If incremental encoder is used for position detection, then the system can operate without absolute position establishment, but abnormality in the encoder cannot be detected prior to establishing absolute position
Solution Approach 1:
The system performs preliminary abnormality detection by calculating and comparing magnetic pole positions using two different methods (incremental encoder-based and absolute position-based) before absolute position establishment is complete. This preliminary check enables abnormality detection in advance, allowing the system to identify detector issues before they cause improper motor driving.
2Reliability
If magnetic pole position comparison method is used for abnormality detection, then abnormality can be detected after absolute position establishment, but detection is not possible before absolute position establishment
Solution Approach 1:
The system performs the magnetic pole position comparison and abnormality detection before absolute position establishment is completed. By calculating the magnetic pole position through both the incremental encoder and the absolute position detector during the origin return process, the system identifies abnormalities in advance, eliminating the delay between abnormality occurrence and detection.
3Reliability
If dual detection system is implemented, then abnormality detection capability is improved, but device complexity increases
Solution Approach 1:
The system makes the absolute position detector serve dual functions: it establishes absolute position during origin return and simultaneously enables abnormality detection by comparing magnetic pole positions. This multi-functionality approach allows abnormality detection without adding a separate dedicated detection system, thereby limiting the increase in device complexity.
Solution Approach 2:
The system implements feedback by continuously comparing the magnetic pole position calculated from incremental encoder data with the magnetic pole position obtained from the absolute position detector. This feedback mechanism enables real-time abnormality detection during the origin return process, improving reliability without requiring complex additional hardware.
Data Source
AI summary
To provide a servo motor controller allowing to eliminate the risk of abnormal driving in a servo motor caused due to the inability to detect abnormality prior to establishment of absolute position. A device is configured to control a servo motor of an industrial machine. The device includes a position detection part configured to detect a position of the servo motor, a magnetic pole detection part configured to detect a magnetic pole position of the servo motor, and a pole position calculation part configured to, at least in initial calculation, obtain the magnetic pole position detected by the magnetic pole detection part as an initial magnetic pole position, prior to establishment of absolute position, and in the following calculation, incrementally obtain the magnetic pole position on the basis of data of the position detected by the position detection part and a magnetic pole interval of the motor.