Frequency-Dependent Pilot Control for Drive Contouring Error Reduction
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Solution Overview
Problem
Existing methods for controlling drives in machining processes, particularly for optical lenses, face challenges in reducing contouring errors which can lead to instabilities and inefficiencies due to high rates of change and accelerations, especially in high-speed cutting applications.
Innovation Solution
The method involves determining a pilot factor based on the frequency of movement corresponding to a reference variable, which is used to adaptively adjust the pilot control, allowing for selective compensation of contouring errors by considering the frequency dependency of the error, thereby minimizing its impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high gain or speed gain control is used to reduce contouring error, then manufacturing precision is improved, but the risk of instabilities increases
Solution Approach 1:
The patent applies dynamics by making the pilot control factor frequency-dependent rather than constant. The control system dynamically adjusts the pilot control strength based on the frequency content of the reference variable, allowing optimal performance across different operating conditions without causing instabilities.
Solution Approach 2:
The patent changes the parameter of the pilot control factor from a fixed value to a frequency-dependent variable. By determining the frequency of the reference variable and selecting different pilot control factors based on frequency ranges, the system optimizes manufacturing precision while maintaining control stability.
2Productivity
If high rates of change of reference variable are used for fast machining, then productivity is improved, but contouring error increases
Solution Approach 1:
The system dynamically adapts the pilot control factor based on the frequency content of the reference variable. When high rates of change occur (high frequency), the system adjusts the pilot control factor to compensate for the increased contouring error, enabling fast machining while maintaining precision.
Solution Approach 2:
The patent implements feedback by determining the frequency of the reference variable and using this information to adjust the pilot control factor. This closed-loop approach allows the system to respond to changing conditions and maintain manufacturing precision even at high productivity levels.
3Manufacturing precision
If frequency-dependent pilot control is implemented, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the frequency spectrum into different ranges and assigning specific pilot control factors to each range. This segmented approach simplifies the implementation of frequency-dependent control compared to designing a completely continuous and complex frequency response.
4Manufacturing precision
If pilot control with high pilot factor is used to reduce contouring error, then manufacturing precision is improved, but the system becomes more sensitive to instabilities
Solution Approach 1:
The patent changes the pilot control factor from a uniformly high value to a frequency-dependent parameter. By selecting appropriate pilot control factors for different frequency ranges, the system achieves high manufacturing precision where needed while maintaining control stability by using lower factors where high values would cause instabilities.
Data Source
AI summary
A method for control of a drive for a tool or workpiece uses pilot control and a device with a control apparatus, the pilot control taking place depending on a frequency of movement. At least one of a frequency component of the reference value, a spectrum of the reference value, and a part thereof is used as the frequency of movement. At least one pilot factor is determined depending on the frequency of movement, and the at least one determined pilot factor, multiplied with a pilot value that corresponds to or is a derivative of the reference variable is used for pilot control. In this way, a contouring error can be advantageously reduced.