非线性电磁振动能量采集的辨识研究

提出一种单自由度电磁振动能量采集器的系统辨识方法——电压映射方法,该方法基于恢复力曲面法的辨识思想,在系统恢复力函数、电磁机电耦合函数和等效电感函数的具体形式未知的情况下,能准确辨识出具有强非线性的恢复力函数、电磁机电耦合函数和等效电感函数。利用两个典型的非线性模型算例进行验证:一是含有非线性弹性恢复力的电磁振动能量采集器系统(电学方程部分为线性);二是既含有非线性弹性恢复力,又含有非线性电学方程的复杂电磁振动能量采集系统。利用龙格库塔法计算得到以上两个算例在简谐振动激励下的时间历程响应,运用上述提出的辨识方法成功辨识得到系统含有的非线性弹性恢复力、阻尼恢复力、电磁力和电感电压,进而得到对应的非线性刚度函数、阻尼函数、电磁机电耦合函数和等效电感函数,结果显示辨识结果与准确结果有良好的一致性,验证了本文所提出方法的有效性和准确性。

System identification of single-DOF electromagnetic vibration energy collector

A system identification method—voltage mapping method for a single degree of freedom electromagnetic vibration energy collector is proposed.The method can accurately identify the recovery force function with strong nonlinearity,electromagnetic electromechanical coupling function and equivalent inductance function even if the specific forms of these functions are unknown.Two typical nonlinear model examples are proposed to verify,one is an electromagnetic vibration energy collector system with nonlinear elastic recovery force(the electrical equation part is linear),and the other is a complex electromagnetic vibration energy acquisition system with nonlinear elastic recovery force and nonlinear electrical equations.Runge-Kutta method is used to obtain the time history response of the above two examples under the excitation of simple harmonic vibration,and the identification method proposed above is used to obtain the nonlinear elastic resilience,damping resilience,electromagnetic force and inductance voltage of the system.Therefore the corresponding nonlinear stiffness function,damping function and electromagnetic electromechanical coupling function and equivalent inductance function can be identified successfully.The results show that the identification results are in good consistency with the accurate results,and the method proposed in this paper is verified to be effective and accurate.