柔性结构的多输入多输出运动系统辨识方法

Identification of Multiple Input Multiple Output Motion System with Flexible Structures

柔性结构的多输入多输出(Multiple input multiple output,MIMO)运动系统的辨识方法是一个具有理论研究和工程应用价值的问题。随着运动系统结构设计、控制性能等要求不断提高,过去视为刚体的MIMO运动系统的柔性动力学特征将越来越显著,成为限制系统性能的重要因素。在辨识试验获得频域非参数模型基础上,提出一种柔性结构的MIMO运动系统辨识方法,基于正交多项式的总体参数曲线拟合得到同分母的MIMO传递函数矩阵,利用模态叠加原理以及奇异值分解(Singular value decomposition,SVD)原理得到系统的状态空间模型。此方法被应用于光刻机工件台这一典型的带有柔性动力学特征的MIMO运动系统。获得的MIMO状态空间模型具有频域辨识模型同等的辨识精度,证明了提出的辨识方法的有效性。所获得的模型满足用于综合控制设计的要求。

It is important study identification method which is applied in multiple input multiple output（MIMO） motion system with flexible structures in theory and practical application.In the past MIMO motion system was usually assumed as rigid body in dynamical modeling.However,the flexible dynamics characteristics will become more and more significant,and become the important factor of limiting the system performance,with the requirements of structure design and control performance enhancing unceasingly.An identification method,which is used to identify the MIMO motion system with flexible structure,is proposed.In this method,nonparametric model is obtained through frequency domain identification experiment,and MIMO transfer function matrix with same the denominator is obtained through the general parameters orthogonal polynomial curve fitting,at last the state space model of MIMO system is obtained through the modal superposition principle of flexible structure and singular value decomposition（SVD） principle.This method has been applied at wafer stage of lithographic equipment which is a typical MIMO motion system with flexible dynamics characteristics.The final MIMO state space model has equal precision with frequency domain identification model,which validates the effectiveness of the proposed identification method.And the obtained model could satisfy the requirement of integrated control design.