2017 Volume 57 Issue 11 Pages 2016-2021
A feedforward control algorithm for the mold oscillators of a continuous casting process is proposed for both sinusoidal and non-sinusoidal oscillations. As steel industries grow, processes allowing for faster continuous casting are required in order to keep up with production demands. To achieve a quicker, continuous casting process, while maintaining slab quality, requires mold oscillations that make use of improved powder consumption rate and reduced friction force. Recently, non-sinusoidal oscillations have been researched owing to their advantages in regards to lubrication and friction. There have been several mechanical approaches but no algorithmic approaches. In this paper, a feedforward control algorithm consisting of embedded input shape and feedforward velocity control algorithms is proposed. Although conventional feedback controls have been commercialized for technical applications, the input shape control algorithm can prevent the non-negligible phase delays or amplitude reduction problems caused by a slow response of systems. In addition, the proposed feedforward velocity control algorithm is derived from the relationship between the valve input and mold velocity, and it allows the mold to correctly follow the non-sinusoidal oscillation. To determine the feasibility of the proposed algorithm, a Matlab Simulink model is derived from the mathematical model. Additionally, 1/100 scale specimen of a typical industry mold oscillator is used. The tests on the specimen showed that the proposed feedforward control algorithm could achieve precise control for both sinusoidal and non-sinusoidal oscillations.
