Die Head MPC Control for Constant Gap on Undulating Substrates
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Solution Overview
Problem
Existing coating methods face challenges in accurately following the shape of substrates with undulations due to differences in control response delays between mechanisms for moving the die head parallel and perpendicular to the substrate, especially at high speeds or with large surface gradients.
Innovation Solution
A control device connected to drive devices for adjusting the positional relationship between the die head and the substrate, using model predictive control to generate operation amounts for precise movement along multiple axes, ensuring the die head maintains a constant distance from the substrate's surface by interpolating shape data to accurately follow the substrate's shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two mechanisms are linked to move the die head parallel and perpendicular to the substrate, then the die head can follow the substrate shape, but control response delay differences cause positioning inaccuracies
Solution Approach 1:
The patent combines the control of two separate drive mechanisms into a unified control system that processes commands sequentially. The first drive mechanism (parallel movement) is fully processed before the second drive mechanism (perpendicular movement) begins, eliminating timing synchronization issues and response delay differences between the two mechanisms.
Solution Approach 2:
The control system generates and processes commands for the first drive mechanism in advance before executing commands for the second drive mechanism. This preliminary processing ensures that positioning commands are prepared and queued before actual movement occurs, reducing control response delays and improving positioning accuracy.
2Productivity
If the die head moves at high speed, then productivity increases, but the control object becomes unable to accurately follow the surface shape
Solution Approach 1:
The control system generates positioning commands in advance based on pre-measured substrate shape data before the die head reaches the corresponding position. This preliminary command generation allows the control system to prepare positioning instructions ahead of time, enabling high-speed movement while maintaining accurate surface following capability.
Solution Approach 2:
The control system dynamically adjusts the timing and sequencing of commands for different drive mechanisms based on real-time position feedback and predicted substrate geometry. This dynamic control allows the system to maintain precision at high speeds by optimizing the response timing of each drive mechanism according to the specific coating conditions.
3Adaptability or versatility
If the substrate has large surface gradients, then the coating can adapt to complex shapes, but the die head becomes unable to accurately follow the surface
Solution Approach 1:
The control system uses pre-measured substrate shape data to generate positioning commands in advance, allowing it to anticipate and prepare for large surface gradients before the die head encounters them. This preliminary command generation enables accurate positioning even on substrates with complex geometries and steep surface variations.
Solution Approach 2:
The control system processes positioning commands for different spatial regions of the substrate separately, with the first drive mechanism handling one region before the second mechanism handles the next. This segmentation allows each mechanism to be optimized for specific portions of the substrate, improving overall positioning accuracy on complex surfaces.
Data Source
AI summary
A control device includes: a first generator generating a first command position of a control object on a plane in each control cycle based on a target trajectory; a first control part generating a first operation amount by model predictive control using a first dynamic characteristic model and the first command position; a second generator generating a second command position of the control object on an orthogonal axis in each control cycle; and a second control part generating a second operation amount by model predictive control using a second dynamic characteristic model and the second command position. Based on shape data indicating a surface shape of an object and the first command position, the second generator generates the second command position so that a distance between the control object and a surface of the object is constant.