一种具有间隙特性的非线性系统的辨识方法

Identification of Nonlinear Systems With Backlash Characteristics

提出了一种具有间隙特性的非线性动态系统的辨识方法。将系统的模型等效为一个间隙特性元件和一个线性动态对象的级联。在测试输入的采样保持周期里对输出做过采样。利用过采样输出,可首先估计出系统线性动态特性的结构参数;进而可还原出间隙特性元件与线性部分的未知中间输入;根据间隙特性的运动规律可分别得到上行线路与下行线路的特征点集;最后利用曲线拟合的方法可获得间隙的宽度和斜率。该方法具有很高的辨识精度和较快的辨识速度。仿真结果表明,利用该方法,间隙宽度的辨识精度可达98%,间隙斜率的辨识精度可达90%。

A novel identification approach is proposed for a class of nonlinear system which consists of a backlash element followed by a linear dynamical system. By only using an observed system output where the test input signal is held during a multiple of output sampling interval, the parameters of the transfer function of＇ the linear part can be identified first. Then the intermediate input between the backlash element and the linear part is reconstructedby using the estimated parameters of the linear part. Basing on the property of the backlash, the two candidate points set of the up route and the down route are distinguished reslpectively. Finally, the backlash slope and the backlash width can be obtained by curve fitting technic. Compared with conventional approaches this method has excellent estimate accuracy and estimate speed. Simulation result Shows that the estimate precision of the backlash slope and the backlash width is 98% and 90% separately.