Servo Control Filter Tuning for Resonance Frequency Shifts
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Solution Overview
Problem
Existing servo control apparatuses cannot effectively adjust filters to account for frequency fluctuations caused by control gain influences on both resonance peak amplitude and resonance frequencies.
Innovation Solution
A servo control apparatus that includes a velocity command creation unit, velocity detection unit, torque command creation unit, filter, sine-wave sweep input unit, frequency characteristics calculation unit, and filter adjustment unit, which together allow for the adjustment of filters based on the influence of velocity control gain on resonance frequencies and peak amplitudes by performing a sine-wave sweep and calculating frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band-stop filter is set up to attenuate servomotor torque strength in the oscillation band, then resonance peak amplitude is reduced, but resonance frequency fluctuations caused by control gain changes are not accounted for
Solution Approach 1:
The filter frequency characteristics are made dynamically adjustable based on the detected resonance frequency. The filter adjustment unit changes the filter's center frequency and bandwidth according to the actual resonance conditions, allowing the filter to adapt to frequency fluctuations caused by control gain changes while maintaining effective resonance suppression.
Solution Approach 2:
The system implements a feedback mechanism where the frequency characteristics calculation unit continuously monitors the servomotor's frequency characteristics, detects resonance frequency changes, and feeds this information back to the filter adjustment unit. This closed-loop feedback enables the filter to automatically track and suppress resonance peaks even when their frequencies shift due to control gain adjustments.
2Measurement precision
If the velocity control gain is adjusted to improve control performance, then control accuracy is enhanced, but resonance frequencies shift making filter tuning difficult
Solution Approach 1:
The filter adjustment unit automatically tunes the filter parameters based on real-time detection of resonance frequency, eliminating the need for manual filter tuning. The system self-adjusts the filter's center frequency and bandwidth by processing frequency characteristic data and automatically applying optimal filter settings, thereby simplifying the overall system operation despite control gain adjustments.
Solution Approach 2:
The system dynamically changes the filter parameters (center frequency and bandwidth) based on the detected resonance frequency and its relationship with control gain. By establishing a quantitative relationship between control gain values and resonance frequency shifts, the system automatically adjusts filter parameters to maintain optimal resonance suppression across different control gain settings.
3Ease of manufacture
If manual filter adjustment is performed without considering control gain influence, then filter setup is simple, but resonance suppression effectiveness deteriorates when control gain changes
Solution Approach 1:
The system performs preliminary detection of resonance frequency characteristics before finalizing filter settings. The frequency characteristics calculation unit analyzes the servomotor's frequency response to identify resonance peaks, and the filter adjustment unit pre-configures optimal filter parameters based on this analysis, ensuring effective resonance suppression from the outset without requiring complex manual tuning.
Data Source
AI summary
A servo control apparatus includes a velocity command creation unit; a velocity detection unit; a velocity control gain; a torque command creation unit; a filter configured to attenuate a particular frequency band component in a torque command value; a sine-wave sweep input unit configured to perform a sine-wave sweep in a predetermined frequency range; a frequency characteristics calculation unit configured to calculate a frequency characteristic of a sine-wave; and a filter adjustment unit configured to attenuate a particular frequency band component in a torque command value. A signal is input to the velocity control gain. The signal is obtained by adding a sine-wave to a difference between a velocity command value and a velocity detected. The filter adjustment unit measures an influence of the velocity control gain on a resonance frequency and resonance peak amplitude, while changing a value of the velocity control gain, thereby adjusting the filter.