Research of Strip Flatness Control Based on Legendre Polynomial Decom- position

Abstract: A traditional least squares has negatively a clear physical significance in the process of strip flatness pattern recognition and it is too complex in calculation to be suitable for industrial controller to realize. In this paper we deduced the basic model of strip flatness pattern recognition based on Legendre polynomial. Under this mode, there are three outstanding advantages: The integral value along the width direction of strip shape is 0, which satisfies the condition of equilibrium in the residual stress. Each component of polynomial corresponds to steer roller, bending roller and step cooling control respectively, which makes the physical meaning clear. Operational calculation is suitable for industrial controller. The simulation shows that calculation time-consuming dropped from average 0.012 s to average 0.002 s. Also practice in the real world had proved that this method is effective and applicable.