多输入多输出非线性系统Volterra频域核的非参数辨识方法

为解决多输入多输出(MIMO)非线性系统Volterra频域核辨识困难的问题,提出了一种MIMO非线性系统Volterra频域核的非参数辨识方法.该方法先对待辨识的MIMO非线性系统的各输入端添加不同频率成分的单音激励信号,再对系统的输出端信号进行采样并使用Vandermonde法使各阶核输出分离,然后根据单音激励下MIMO非线性系统Volterra核的频域输出特性,推导出该类系统Volterra频域核的辨识公式.由于采用了多音信号激励MIMO非线性系统,实现了一次激励下多点辨识的目的,因此提高了辨识效率.该方法仅依赖于系统的输入输出数据,具有较强的实用性.采用该方法对一个双输入双输出的非线性系统Volterra频域核进行辨识,最大偏差小于10-5,验证了该方法的有效性.

A Non-Parametric Identification Method of Volterra Frequency Domain Kernels for MIMO Nonlinear System

A novel non-parametric identification method is proposed to solve the hard problem in identifying Volterra frequency domain kernels of multi-input multi-output(MIMO) nonlinear systems.Firstly,the single tone stimuluses with different frequency components are added to the input ports of the system under test.Secondly,the output signals of the system are sampled and every order kernel output is separated by using the Vandermonder method.Thirdly,a formula is derived in terms of output properties of Volterra kernels of MIMO nonlinear system stimulated by single tone.Since the multitone signal is applied to stimulate MIMO nonlinear system,multi-point of Volterra frequency domain kernels can be simultaneously identified in a single-round test,and hence,the efficiency of the proposed method is improved.The proposed method is more practical because it only relies on input-output data of systems.The proposed method is applied to identify the Volterra frequency domain kernels of a two-input two-output nonlinear system.The results show that the maximum deviation in identification is less than 10-5,and hence,the proposed method is effective.