Sheet Transport Control Device for Tension Accuracy
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Solution Overview
Problem
Conventional sheet transport systems using multiple rollers face challenges in accurately controlling sheet tension and state quantities, particularly with short sheets, leading to slippage and control inaccuracies when relying on a single roller for tension adjustment.
Innovation Solution
A control device calculates and inputs specific control signals to multiple rollers to manage sheet state quantities and tension simultaneously, using a computer program to adjust the driving inputs of the first and second driving devices, and includes mechanisms to estimate and correct for non-tensional components in reaction forces to enhance control accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only one roller (send-out roller) is used for tension control, then the control system remains simple, but tension control accuracy deteriorates leading to slippage
Solution Approach 1:
The patent divides the single roller tension control into multiple segments by introducing separate first and second driving devices for the first and second rollers respectively. Each driving device independently controls its roller, enabling distributed tension control across multiple contact points, which improves tension control accuracy while maintaining reasonable system complexity through modular control architecture
Solution Approach 2:
The patent introduces a control device as an intermediary that calculates and distributes control signals to multiple driving devices. This intermediary coordinates the complex multi-roller tension control by computing appropriate control inputs based on sheet state quantities, effectively managing the complexity while achieving high-accuracy tension control through centralized calculation and distributed execution
2Stability of the object's composition
If multiple rollers are used for sheet transport, then transport stability improves, but control accuracy of state quantity and tension deteriorates
Solution Approach 1:
The patent applies local quality by assigning different control functions to different rollers based on their positions. The first driving device controls the first roller with control input U1, while the second driving device controls the second roller with control input U2. Each roller provides localized support and control, maintaining transport stability while enabling precise local adjustment of sheet state quantities and tension
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the control inputs U1 and U2 to the first and second driving devices based on real-time sheet state quantities. By changing the driving parameters of multiple rollers in a coordinated manner, the system maintains transport stability while achieving accurate control of sheet position, speed, and tension through continuous parameter optimization
Data Source
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AI summary
There is provided a transport system including: a transport mechanism including first (110, 115) and second (120, 125) rollers; first (73) and second (83) driving devices; first and second measuring devices configured to measure a state quantities Z1 and Z2; and a controller configured to control the first and second driving devices. The controller is configured to perform: estimating reaction forces R1 and R2; calculating control inputs U1 and U2; inputting, to the first driving device, a control signal in accordance with a sum of the control input U1 and the control input U2; inputting, to the second driving device, a control signal in accordance with a difference between the control input U1 and the control input U2; estimating non-tensional components RE1 or RE2; and correcting the control input U2 to prevent a control error caused by the non-tensional components RE1 and RE2 included in an estimated tension of the sheet (R1 - R2)/2.