伺服系统Hammerstein非线性模型及参数辨识方法研究  

Nonlinear Hammerstein Model and Parameter Identification for Servo Drive System

作　　者：刘栋[1] 陶涛[1] 梅雪松[1,2] 

机构地区：[1]西安交通大学机械工程学院,西安710049 [2]西安交通大学机械制造系统工程国家重点实验室,西安710049

出　　处：《西安交通大学学报》2010年第3期42-46,共5页Journal of Xi'an Jiaotong University

基　　金：国家科技重大专项资助项目(2009ZX04014-023);国家重点基础研究发展规划资助项目(2005CB724106);国家高技术研究发展计划资助项目(2008AA042405)

摘　　要：在伺服系统建模中,针对线性模型无法表达系统在低速、运动换向条件下摩擦与死区等非线性现象的问题,采用包含静态非线性部分和动态线性系统的Hammerstein模型来代替线性模型对伺服系统进行了描述.根据静态非线性模型逼近伺服系统的非线性特性,非线性模型采用分段非对称多项式基函数来解决摩擦在运动中存在的非对称特性.对于多频率正弦输入信号和伺服系统的速度输出信号,由迭代最小二乘方法来估计模型的参数.通过辨识实验中的线性模型和Hammer-stein模型的输出,说明采用Hammerstein模型方法能有效地对系统非线性部分建模,Hammer-stein模型的输出误差比线性模型的输出误差约减少90%,因此显著地提高了系统的模型精度,实现了对系统非线性动态行为的精确预测.Aiming at resolving the problem that linear models are not able to express the influence of the nonlinear phenomena in servo drive system,such as stick-slip friction,dead-zone etc,on condition of low-velocity or changing of directions,the Hammerstein model which contains static nonlinearity and dynamic linearity is adopted to describe servo system instead of linear model.The nonlinear characteristic of servo system is approximated by static nonlinearity,where two-segment polynomial is used to describe asymmetrical characteristics of friction.The recursive least square method is performed to estimate the parameters of model with multi-frequency sinusoidal input signal and velocity output signal of the servo system.The comparison of the model output between the linear model and the Hammerstein model in identification experiments indicates that the Hammerstein model can effectively represent the nonlinear characteristics of servo system,the error of the Hammerstein model output can be reduced by 90% of that of the linear model to greatly improving,the identification accuracy and precisely predicting the dynamic response of system in nonlinear states.

关 键 词：伺服系统 HAMMERSTEIN模型 非线性模型 

分 类 号：TP271.3[自动化与计算机技术—检测技术与自动化装置]