Rolling Mill Tension Control With Speed-Adaptive Drive Gain
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Solution Overview
Problem
Existing tension control methods in rolling mills are too slow to effectively correct tension disturbances caused by irregularities such as mass flow changes, new material, or roll wear, leading to unstable rolling processes and potential band cracks.
Innovation Solution
A method that varies the conversion of the controller output signal into an actuating signal based on the speed of the metal band, using a gain factor to adapt the tension control dynamically, allowing for faster and more precise correction of tension disturbances, particularly through the use of learning points and speed-dependent adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotary drive of the rolls is used as the actuating element for tension control, then the tension can be regulated, but the response speed is too slow to correct tension disturbances effectively
Solution Approach 1:
The patent applies dynamics by making the system gain V(t) variable over time based on the band speed g(t). The gain factor is adapted dynamically using learning points recorded at different speeds, allowing the tension control to respond faster to disturbances while maintaining stability. This resolves the contradiction by enabling the rotary drive to act as an actuating element with improved response characteristics.
2Speed
If the position control of working rolls is used for tension control, then the action on tension is faster, but the adaptability to speed changes is reduced
Solution Approach 1:
The patent changes the parameter of system gain V(t) as a function of band speed g(t). By recording learning points at different speeds and adapting the gain factor accordingly, the system maintains fast action on tension while becoming adaptable to speed changes. The gain is varied temporarily in dependence on speed, resolving the contradiction between fast action and adaptability.
3Ease of manufacture
If a fixed gain controller is used, then the setup is simple, but the correction speed varies with speed changes
Solution Approach 1:
The patent applies preliminary action by recording learning points at different speeds before actual operation. These pre-recorded gain factors are stored and automatically selected based on the current band speed, eliminating the need for complex real-time calculations during operation. This maintains setup simplicity while enabling speed-adaptive correction speed through pre-computed gain factors.
Data Source
AI summary
A method for tension control in a band-shaped material between two tension points, in particular between two adjacent roll stands, wherein at least one of the tension points has a rotary drive as an actuator. In order to make known tension controls of this type more effective and faster the controller output signal is varied in connection with the conversion thereof into the actuating signal for the rotary drive, at least temporarily, in dependence on a variable representing the band-shaped material.