Flatness systems

Accurate measurement for accurate control. By taking into consideration the dynamic behavior of the actuators at the point of flatness error evaluation, correction is applied rapidly and smoothly.

Flatness system: overview

Total control is the difference. The Stressometer flatness control system will minimize rejects, pass times and strip breaks. This is achieved through the use of all mill actuators, both mechanical and thermal, in an optimal way for creating the best possible flatness.

Benefits

The flatness system will simultaneously control all available mechanical actuators in the mill. All actuators have accurate models, defining the flatness action, stored in the system. These models are used for optimally extracting actuator components from the flatness error. Some features of the mechanical flatness control:

Predictive control

Achieves major yield improvements and reduces rejects by over 50%. Uses dead time compensation for faster control during speed changes.

Accurate actuator models and tuning capabilities

Models easily tuned during commissioning and adapted on-line. Process parameters automatically identified with one click.

Change of control strategies on-line

Customized control strategies for each mill. System automatically selects and activates the optimal strategy for each situation.

Flatness control with extended singular value decomposition (ESVD)

Finds optimal actuator combinations while considering all constraints. Ensures robust, fully automatic control with minimal actuator wear.

Identification of process model

Reliable model identification during rolling within seconds with negligible disturbance. Maximizes flatness quality through accurate process models.