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.

中文翻译：

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伺服电机驱动连铸结晶器振动位移前馈反馈复合控制

针对伺服电机驱动的连铸结晶器振动位移系统要求电机按一定的固定方向旋转的特点，本文提出了前馈和反馈控制相结合的复合控制方案。在控制器设计中，主要需要考虑两个问题： i) 伺服电机沿固定方向旋转而模具以周期形式振动的约束条件。ii) 时变载荷和机械因素引起的不确定性，如机械零初始偏差和加工精度。针对系统的不确定性和模具的周期性振动位移，采用比例积分（PI）控制器结合重复控制方法实现位移跟踪，提高跟踪性能。采用由参考模具位移及其一阶导数组成的前馈控制算法求解约束条件。最后，一些仿真结果表明了该算法在约束条件和系统不确定性方面的可行性。此外，由伺服电机驱动的典型工业模具振动系统进行了展示所提出的控制方案的有效性。