Motor Controller Preprocessing Reduces Vibration
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Solution Overview
Problem
In motor controllers, compensation filters with characteristics that raise gain in specific frequency regions can amplify small variations in command values, leading to vibrations or unusual sounds in driven units, particularly in industrial machines.
Innovation Solution
A motor controller design that includes a preprocessing unit before the compensation filter, which uses a past command value as the current command value when the variation is equal to or less than a predetermined value, preventing amplification of small variations and thus reducing vibrations or unusual sounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compensation filter with gain-raising characteristic is used in a specific frequency region, then the compensation effect is improved, but small variations in command value are amplified causing vibrations or unusual sounds
Solution Approach 1:
The preprocessing unit performs dead zone processing on the command value before it enters the compensation filter. This preliminary action prevents small variations from being amplified by the filter's gain-raising characteristic, thereby avoiding vibrations and unusual sounds while preserving the compensation effect for significant command changes
Solution Approach 2:
The preprocessing unit acts as an intermediary between the command value input and the compensation filter. It mediates by filtering out small variations through dead zone processing before the signal reaches the compensation filter, thus preventing the harmful amplification of noise while allowing the filter to perform its compensation function on valid command variations
Data Source
AI summary
A motor controller includes: a command unit which outputs a command value for controlling a motor that drives a driven unit; a motor control unit which controls the motor based on the command value; a compensation filter which compensates for the command value; and a preprocessing unit which is provided in a stage preceding the compensation filter, the compensation filter has a frequency region in which a gain is greater than 1 and the preprocessing unit executes, when a variation in the command value before being compensated for with the compensation filter is equal to or less than a predetermined value, preprocessing in which a past command value is used as a current command value.