Scanner Closed-Loop Control Using Frequency-Space Error Correction
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Solution Overview
Problem
Conventional closed-loop control systems for scanners, such as those used in laser scanning microscopes, face challenges in achieving high accuracy and reliability due to system deviations between the target and actual poses of the deflection unit, leading to image distortions and double contours.
Innovation Solution
A method for closed-loop control that involves receiving an input signal indicative of the system deviation, expanding it into error components at various frequencies, determining correction signal components based on frequency response components, and outputting a control signal to correct these deviations, allowing for precise control of the scanner's pose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PID controllers are used for closed-loop control, then the control system is simple to implement, but the accuracy and reliability are insufficient due to uncorrected system deviations
Solution Approach 1:
The patent segments the error signal into multiple frequency components using Fourier transformation. Each frequency component is processed independently through separate correction channels, allowing targeted correction of different types of deviations (periodic errors, harmonics, etc.) while maintaining overall system manageability
Solution Approach 2:
The patent transforms the control problem from the time domain to the frequency domain. By analyzing and correcting errors in the frequency dimension rather than directly in time, the system achieves higher precision correction of scanning angle deviations without proportionally increasing time-domain control complexity
2Manufacturing precision
If frequency-space analysis is implemented to correct all error components, then the scanning accuracy is significantly improved, but the computational complexity and processing time increase
Solution Approach 1:
The patent implements partial correction by focusing on the most significant frequency components (fundamental frequency and major harmonics) rather than attempting to correct all frequency components with equal detail. This selective approach achieves substantial accuracy improvement while limiting computational overhead
Solution Approach 2:
The patent performs preliminary Fourier transformation and frequency component identification before the main correction process. By pre-processing the error signal to identify dominant frequency components, the system prepares correction data in advance, reducing real-time processing demands during actual scanning operations
Data Source
AI summary
The invention is based on the object of providing a particularly reliable closed-loop control for a scanner. According to various examples, this object is achieved by an analysis of a system deviation in the frequency space. By way of example, an input signal, which is indicative of a time dependence of the system deviation between an ACTUAL pose and a TARGET pose of a deflection unit of the scanner, can be expanded into a multiplicity of error components and a plurality of frequencies. Then, a corresponding correction signal component can be determined for each of the multiplicity of error components. By way of example, such techniques can be used in a laser scanning microscope.