Feedforward and Feedback Compound Control of Vibration Displacement for a Continuous Casting Mold Driven by a Servo Motor

Abstract

In view of the fact that the vibration displacement system of continuous casting mold driven by a servo motor requires the motor rotate in a certain fixed direction, a compound control scheme combining feedforward and feedback control is proposed in this paper. In controller designing, there are mainly two issues to be considered: i) constraint condition that the servo motor rotates in a fixed direction while the mold vibrates in a periodic form. ii) uncertainties caused by time-varying load and mechanical factors, such as mechanical zero initial deviation and machining precision. As to the system uncertainties and the periodic vibration displacement of mold, proportional-integral (PI) controller combined with the repetitive control method are used to realize displacement tracking and improve the tracking performance. A feedforward control algorithm consisting of the reference mold displacement and its first derivative is adopted to solve the constraint condition. Finally, some simulation results show the feasibility of the proposed algorithm for the constraint condition and system uncertainties. Additionally, a typical industry mold vibration system driven by a servo motor is conducted to show the effectiveness of the proposed control scheme.