The Stressometer System offers many advanced functions for achieving optimal flatness performance. Automatic Flatness Control (AFC) is based on a mathematical operation which reduces the conflicts between what is required and what is possible, based on actual operational parameters derived from the mill itself.
The difference between the measured strip flatness and the target curve is the "flatness error". By using a range of control functions within the mill the roll gap can be adjusted to minimise the flatness error.
Highly accurate mill models for all types of mills
The mill model is achieved by assessment of how the mill responds to control commands. The actual response for each actuator can be derived on-line, or created from a theoretical model, then established by actual operation and expressed as a mathematical function. The combined reaction for all actuators in a mill creats an equation within the operational software which is used to decide how to control the mill in order to achieve optimal flatness performance.
Automatic adaption achieves optimal flatness
Multiple actuators with similar function can interfere with each other. Limiting this interference means applying a certain type of priority to each of them. The most efficient combination of control actions to reduce the flatness error is a least square fit of the action curves to the flatness error, adapting to the actuator priorities. Thus resolving the difference between actual and target flatness.