Gantry Stage Thermal Deformity Compensation

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Solution Overview

Problem

Linear motion single-plane gantry stages face accuracy degradation due to dynamic and thermal deformity errors, which existing technologies fail to address effectively through real-time compensation.

Innovation Solution

A system comprising two-dimensional position measuring units on both sides of the gantry stage and a compensation control unit that measures and filters signals from encoder heads to provide real-time correction for linearity, yaw, and thermal deformity errors, using low pass filters to eliminate noise and update control loops for precise motion control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If real-time compensation for dynamic and thermal deformity errors is implemented, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent segments the error compensation by separating dynamic errors (linearity and yaw errors during motion) from thermal deformity errors. Two distinct measurement systems are employed: one for dynamic errors and another for thermal errors, allowing independent measurement and compensation strategies for each error type, thereby managing system complexity through modular segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediary measurement devices (laser interferometers and thermal sensors) that act as mediators between the gantry stage and the control system. These intermediaries directly measure the errors and provide data to the compensation algorithm, enabling accurate error detection without requiring complex direct measurement of the stage's positional deviations.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If two-dimensional position measuring units are installed on both sides of the gantry stage, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidmeasurement system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the measurement functions by using identical two-dimensional position measuring units on both sides of the gantry stage. These units use the same laser interferometer technology and measurement principles, allowing data from both sides to be combined and processed together to achieve higher measurement precision through redundancy and cross-validation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from one-dimensional linear measurement to two-dimensional position measurement by adding vertical height measurement capability to the position measuring units. This dimensional expansion allows simultaneous measurement of both horizontal position and vertical height, providing comprehensive spatial measurement data for accurate error compensation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system achieves accurate real-time compensation for dynamic and thermal deformity errors, enhancing the precision and quality of products by filtering high-frequency noise and providing low-frequency error signals for effective linearity and yaw error correction.

Implementation Method 1

measuring and filtering signals from encoder heads to provide real-time correction for linearity, yaw, and thermal deformity errors, using low pass filters to eliminate noise

Methodology Applied
Scientific EffectLow pass filtering: Filter (electronic)

Implementation Method 2

a thermal fixing point provided as a thermal reference for measuring a thermal expansion of the X-axially moving gantry beam

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2881699B1System for compensating dynamic and thermal deformity errors of a linear motion single-plane gantry stage in real time
Publication Date: 2018.04.18 SOONHAN ENG
  • EP2881699B1 patent drawingFigure 1
  • EP2881699B1 patent drawingFigure 2~3
  • EP2881699B1 patent drawingFigure 4~5

AI summary

Disclosed are a system for compensating dynamic and thermal deformity errors of a linear motion single-plane gantry stage in real time, a stage apparatus using the system, and manufacturing, measuring and inspecting apparatuses using the system. The system includes: a first two-dimensional position measuring unit arranged in each of two linear edge beams respectively positioned in both sides of the linear motion single-plane gantry stage for measuring the position of an X-axially moving gantry beam to provide a feedback of an X-axial motion thereof; a second two-dimensional position measuring unit for measuring the position of a Y-axially moving slider moving on the X-axially moving gantry beam to provide a feedback of a Y-axial motion thereof; a thermal fixing point provided as a thermal reference for measuring a thermal expansion of the X-axially moving gantry beam; and a compensation control unit for controlling an error motion of the linear motion single-plane gantry stage in real time by measuring dynamic and thermal deformity errors based on the data received from the first and the second two-dimensional position measuring unit (FIG. 1).