Servo Filter Tuning by Resonance Priority on the Nyquist Locus
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Solution Overview
Problem
When there are multiple resonance points in a servo control system, adjusting filters without knowing the priority of each resonance point can lead to ineffective application, as filters may not be applied to the most critical resonance points first.
Innovation Solution
A control assistance device that detects resonance points in the frequency characteristics of a servo control device and calculates priority levels based on the distance between specific points on a complex plane, allowing filters to be allocated in order of priority.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filters are adjusted without knowing the priority of resonance points, then the adjustment process is simple, but the filters may be applied in an ineffectual manner
Solution Approach 1:
The patent applies preliminary action by calculating priority levels of resonance points before applying filters. The resonance evaluation unit computes priority levels based on distances from reference points on the complex plane, establishing a predetermined order for filter application. This ensures that the most critical resonance points are addressed first, making the filter adjustment process effective rather than ineffectual.
2Productivity
If priority levels are calculated for all resonance points, then filters can be allocated in order of priority, but the calculation complexity increases
Solution Approach 1:
The patent applies parameter changes by transforming the resonance evaluation into a mathematical calculation of distances on a complex plane. Instead of complex qualitative assessment, the system calculates numerical priority levels based on distances from reference points (-1, 0) or (k, 0) where k < -1. This parameter transformation makes the evaluation systematic and computable, improving filter allocation efficiency while keeping the difficulty manageable through mathematical formulation.
Data Source
AI summary
A control assistance device implements assistance in order to adjust a coefficient for a plurality of filters provided to a servo control device. The control assistance device comprises: a resonance detection unit that detects a plurality of resonance points in frequency characteristics between an input/output gain and an input/output phase shift, of the servo control device, measured on the basis of an input signal and an output signal having varying frequencies; and a resonance evaluation unit that calculates the priority levels of the plurality of resonance points. The resonance evaluation unit calculates the priority level on the basis of a distance between a point (-1,0) or a point (k, 0) (where k is a value less than -1) on a real axis on a complex plane, and a resonance point on a Nyquist locus calculated from the frequency characteristics between the input/output gain and the input/output phase shift.