无记忆非线性系统参数估计及空间位置辨识仿真分析

Simulation Analysis of Parameter Estimation and Spatial Location Identification of Memoryless Nonlinear System

以无记忆非线性系统为研究对象,将非线性响应力作为外部载荷,将其与外力和响应位移一起构成多输入单输出系统;然后给出适用于空间任意位置的非线性单元参数估计方法;最后基于"反向路径法"和重相干函数给出利用随机激励和响应信号辨识非线性单元空间位置的方法,并通过两个仿真案例进行验证。结果表明,非线性单元参数估计方法可准确计算非线性系统的强迫响应,并实现非线性单元空间位置的准确辨识和参数的准确估计。

A zero-memory nonlinear system is considered in this paper. Firstly, the nonlinear restoring force is treated as external loads and used together with input force and output displacement to form a general multiple input single output system. Then an improved parameter estimation method, which is suitable for nonlinear elements presented at any spatial location, is presented. Finally, based on‘Reverse Path’method and multiple coherence function, random excitation and response data are used to identify the spatial location of nonlinearity. Two numerical simulations are used to verify the presented approach. The results indicate that the presented approach works well for calculating the forced response, as well as for identifying the nonlinear location and estimating the nonlinear parameter.