Servo Parameter Tuning From Measured Machine Frequency Response
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Solution Overview
Problem
Existing servo control systems face challenges in achieving stable high-speed and high-precision positioning due to variations in the frequency characteristics of actual machines caused by machine stand variations, leading to issues like unusual sound and vibration, and require complex physical modeling that is time-consuming and limited by DSP calculation capabilities.
Innovation Solution
A servo control apparatus that includes a command generator, detector, actual machine frequency characteristic measurer, and parameter adjuster to dynamically adjust controller parameters based on measured frequency characteristics, ensuring stable control across varying load device positions without causing sound or vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If control parameters are adjusted based on frequency characteristics measured at one load device position, then control performance is improved at that position, but control performance deteriorates at other positions due to frequency characteristic variations
Solution Approach 1:
The patent implements dynamic parameter adjustment by continuously adapting controller parameters based on real-time frequency characteristic measurements. The parameter adjuster dynamically modifies controller parameters in response to detected frequency variations caused by load device position changes, transforming the static control system into a dynamic one that automatically adapts to varying operating conditions.
Solution Approach 2:
The patent employs feedback mechanisms where the frequency characteristic measurer continuously monitors the actual frequency characteristics, and this information feeds back to the parameter adjuster which modifies controller parameters accordingly. This closed-loop feedback system ensures that control parameters remain optimized despite variations in load device position or machine stand characteristics.
2Manufacturing precision
If complex physical modeling is used to account for frequency characteristic variations, then control accuracy is improved, but device complexity and calculation burden increase
Solution Approach 1:
Instead of using complex physical models, the patent creates a virtual copy of the actual frequency characteristics by directly measuring them. The frequency characteristic measurer captures the real-world frequency response, and this measured data is used to adjust controller parameters, replacing the need for complicated theoretical physical modeling with straightforward empirical measurement.
Solution Approach 2:
The patent substitutes complex mechanical/mathematical modeling with direct measurement and signal processing. Rather than calculating frequency characteristics through complex physical models of the machine structure, the system directly measures the frequency response using excitation signals and spectral analysis, replacing theoretical modeling with empirical measurement.
3Measurement precision
If DSP calculation capabilities are increased to handle complex physical models, then modeling accuracy is improved, but cost and system complexity increase
Solution Approach 1:
The patent applies partial action by focusing measurement and adjustment efforts only on the critical frequency characteristics that most affect control performance. Rather than attempting to model or measure all possible system parameters, the system targets the specific frequency range and characteristics that have the greatest impact on positioning accuracy, reducing unnecessary computational burden.
Data Source
AI summary
A servo control apparatus includes an actual machine frequency characteristic measurer that calculates a frequency characteristic of an actual machine from a motor input signal and an output of a detector, and a parameter adjuster that finds a solution for a parameter of a controller, which sets a difference, between an open loop characteristic, calculated from a calculation result of the actual machine frequency characteristic measurer and a frequency characteristic of the controller, and an ideal open loop characteristic, to be less than or equal to a predefined reference, and that applies the obtained parameter to the controller.