Die Head MPC Control for Constant Gap Surface Following
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Solution Overview
Problem
Existing coating methods struggle to accurately follow the shape of substrates with undulations due to differences in control response delays between mechanisms 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 multiple drive devices, utilizing model predictive control to generate operation amounts for moving the die head along a plane and orthogonal to it, ensuring accurate positioning based on shape data to maintain a constant distance from the substrate, thereby improving tracking of the substrate's surface.
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 control system is segmented into independent first and second control parts, each responsible for one drive mechanism. This segmentation allows independent optimization of control parameters for each mechanism, addressing their different response characteristics without requiring complex coupled control algorithms.
Solution Approach 2:
The system performs preliminary action by pre-calculating and outputting operation amounts to both drive devices in advance within each control cycle. This anticipatory control compensates for response delays before they manifest as positioning errors, improving accuracy without increasing real-time computational complexity.
2Productivity
If the die head moves at high speed to improve productivity, then coating efficiency increases, but the control object becomes unable to accurately follow the substrate shape
Solution Approach 1:
The control device outputs operation amounts to both drive devices in advance within each control cycle, performing preliminary control actions that anticipate the high-speed movement requirements. This allows the system to maintain shape-following accuracy even at high coating speeds by pre-compensating for inertial and response delays.
Solution Approach 2:
The control system maintains continuous operation amount output to both drive devices throughout the coating process, ensuring uninterrupted and synchronized control actions. This continuous control enables the die head to smoothly follow substrate undulations at high speeds without losing positioning accuracy.
3Adaptability or versatility
If the substrate has large surface gradients, then more complex surface shapes can be coated, but the die head becomes unable to accurately follow the surface shape
Solution Approach 1:
The control system segments the complex positioning task into two independent control channels (first and second drive devices), each optimized for specific movement directions. This segmentation allows each control part to independently handle large gradients in its respective direction, maintaining overall positioning accuracy on complex surfaces.
Solution Approach 2:
The control system dynamically adjusts operation amounts for both drive devices based on real-time substrate shape requirements. This dynamic control enables the die head to adapt to large surface gradients by continuously optimizing the coordination between parallel and perpendicular movements, maintaining accuracy on varied surface geometries.
Data Source
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AI summary
A control device is provided with: a first generation unit for generating a first instruction position on a plane of a control subject in each control period on the basis of a target trajectory; a first control unit for generating a first operation amount by model prediction control using a first dynamic characteristic model and the first instruction position; a second generation unit for generating a second instruction position on an orthogonal axis of the control subject in each control period; and a second control unit for generating a second operation amount by model prediction control using a second dynamic characteristic model and the second instruction position. On the basis of shape data indicating a surface shape of an object and the first instruction position, the second generation unit generates the second instruction position in such a manner that a distance between the control subject and a surface of the object is constant. As a result, the control subject follows the shape of the surface of the object with high accuracy.