Servo Motor Z-Phase Interval Checking for Noise-Robust Positioning
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Solution Overview
Problem
Noise interference during the detection of Z-phase signals in servo motors using incremental encoders leads to errors in absolute position detection, making accurate position control difficult.
Innovation Solution
A servo motor controller that includes a position detection unit, a signal interval detection unit to measure Z-phase signal intervals, and an abnormality determination unit to identify abnormalities by checking if the signal intervals exceed a threshold, allowing for accurate position control by eliminating erroneous detections due to noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Z-phase signal detection is performed during servo motor operation, then absolute position detection can be achieved, but noise interference causes detection errors at certain speeds
Solution Approach 1:
The system performs preliminary detection of multiple Z-phase signals before final position establishment. By detecting a plurality of Z-phase signals and verifying their intervals in advance, the system ensures accurate position detection without noise interference, allowing reliable absolute position control to be achieved.
2Productivity
If Z-phase signal detection is performed at high speed, then productivity is improved, but noise interference increases causing detection errors
Solution Approach 1:
The system uses feedback by measuring the interval between detected Z-phase signals and comparing it with a predetermined threshold. When the interval falls within the expected range, the detection is confirmed as valid; otherwise, it is identified as noise and rejected. This feedback mechanism enables accurate position detection even at high speeds where noise interference is present.
3Measurement precision
If multiple Z-phase signals are detected and intervals are measured to eliminate noise, then position control accuracy is improved, but detection time increases
Solution Approach 1:
The system changes the parameter of interval threshold comparison to quickly identify valid Z-phase signals. By setting a predetermined threshold for the interval between Z-phase signals, the system can rapidly determine whether detected signals are valid or noise, achieving accurate position detection without excessive detection time.
Data Source
AI summary
A servo motor controller capable of eliminating inconvenience that the position of a shaft or the like of a servo motor is detected or set erroneously due to influence of noise or the like is provided. A servo motor controller that detects Z-phase signals of an incremental-type encoder that detects rotation of a servo motor to perform driving control of the servo motor includes: a position detection unit that detects a reference position of a rotating shaft of the servo motor on the basis of the Z-phase signal of the encoder; a signal interval detection unit that measures intervals of a plurality of detected Z-phase signals; and an abnormality determination unit that determines that the Z-phase signal is abnormal when the interval measured by the signal interval detection unit is equal to or larger than a prescribed threshold.