伺服电机驱动连铸结晶器按期望规律振动是一种新型的驱动方式。伺服电机驱动的连铸结晶器振动系统,可避免现有其它方式驱动连铸结晶器振动的不足,具有节能降耗、使用寿命长等优点。为了提高连铸结晶器振动速度或位移的控制精度,保证结晶器振动的平稳性和铸坯质量,建立系统较精确的数学模型是关键。因此,本文首先通过实验研究辨识得到伺服电机转速闭环模型,并推导了机械传动部分的机理模型,从而建立了伺服电机驱动的连铸结晶器振动台系统的数学模型,并给出了一种状态空间表达式;其次,对所建立的模型进行验证,通过相同输入作用下所建模型的仿真输出与实际系统的实测输出的比对,结果表明该模型能较好地反映系统的性能,从而验证了本文所建立模型的有效性;最后对建模误差进行了定量分析,结果表明:模型拟合精度可达94%以上,进一步确认了模型的准确性。所建系统的模型及其误差分析为下一步连铸结晶器位移系统跟踪控制器的设计奠定了良好基础。
Servo motor driver is a new kind of driving way which can realize continuous casting mold oscillating according to the expected rule. The oscillation system of continuous casting mold driven by servo motor not only can avoid some shortages that exist in other existing devices, but also has some advantages, such as energy conservation and low consumption, long performance life time and so on. In order to improve control precision of the continuous casting mold speed or position, and ensure the stability of oscillation and casting quality, it is important to establish accurate mathematical model of the system. Firstly the closed-loop model of servo motor rotation rate is identified in the experiment, and the mechanism model of mechanical transmission parts are derived, so the mathematical model of system for oscillation platform of continuous casting mold driven by servo motor is established, and one model of state equation is given. Then the established model is verified by comparing the output of the established model with the actual system, the results show that the model can accurately represent the characteristics of the system. Finally, through the quantitative analysis for the modeling error, model fitting precision can reach 94%, which confirms the accuracy of the model. The model and error analysis is a foundation for designing the tracking controller of continuous casting mold position system.