摘要 |
The present invention provides a method of controlling the height of a looper in an inter-stand section of a hot strip mill that overcomes the problem of looper instability due to looper inertia without the need for the controller of upstream rollers to have a reduced gain. The inter-stand section of the hot strip mill comprises a pair of upstream rollers driven by a main motor and a looper driven by a looper motor. The method comprises the steps of: calculating a desired speed trim to be applied by the main motor; estimating the inertia of the looper; calculating a torque necessary to overcome the inertia of the looper from the speed trim, the estimated inertia of the looper and a sensitivity calculated from the geometry of the looper; and controlling the main motor to apply the speed trim to the upstream rollers and controlling the looper motor to apply the calculated torque to the looper. |