Nucor Corporation

George T C Chiu

Neera Jain Sundaram

Harold Bradley Rees

Florian Maurice Browne, Iii

Walter N Blejde

Robert Nooning, Jr

Ivan David Parkes

Jianqi Ruan

A twin roll casting system includes a pair of counter-rotating casting rolls, a casting roll controller is configured to receive a plant input comprising at least one process control setpoint for the casting rolls. A cast strip sensor measures at least one parameter of the cast strip. A feedback controller receives measurement signals from the cast strip sensor. The feedback controller is a data-driven model including a database of state-input pairs; and executes the following steps at each time step: measure a state-input similarity between a new state observation and samples, assign a weight to each consequent output of samples based on the measured state input similarity, and sum the weighted outputs and predict an output of a new state observation. The feedback controller is configured to provide the control setpoint to the casting roll controller based on the predicted output of the new state observation.

Training-free data-driven method for input-output modeling of complex process

A twin roll casting system includes a pair of counter-rotating casting rolls having an adjustable nip therebetween, a casting roll controller configured to adjust the nip between the casting rolls in response to control signals; a cast strip sensor measuring a parameter of the cast strip and generating strip measurement signals; and an iterative learning control (ILC) controller receiving the strip measurement signals and providing control signals to the casting roll controller. The ILC controller includes a fault detection algorithm receiving the control signals and the strip measurement signals and generating a fault detection signal indicating when a fault condition is detected and an iterative learning control algorithm to generate the control signals. The fault detection algorithm indicates a fault condition when it detects the control signal exceeding an upper control saturation threshold or the ILC controller operating a state that is not guaranteed as stable.

Fault detection for iterative learning control of time-varying systems

A twin roll casting system where the casting rolls have a nip between the casting rolls, each roller having a circumference and a rotational period. The casting roll controller adjusts the nip between the casting rolls in response to control signals. The sensor measures at least one parameter of the cast strip. The ILC controller receives strip measurement signals from the sensor and provides control signals to the casting roll controller. The ILC controller includes an ILC control algorithm to generate the control signals based on the strip measurement signals and a time delay estimate based on circumference, rotational period, and a length of cast strip between the nip and the sensor to compensate for an elapsed time from the cast strip exiting the nip to being measured by the cast strip sensor.

Iterative learning control for periodic disturbances in twin-roll strip casting with measurement delay

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West Lafayette, IN, United States of America

George T C Chiu