基于边界辨识的水下航行器低频线谱主动调控

Voice print is one of the most important tools that sonar detects and identifies vessels. Nonlinear vibration isolation systems alter the output spectrum shape as operating in unstable vibration station, which can be applied to the modification of spectral lines of the vibrations of the ship body induced by the onboard mechanical equipment. This project tries to develop method of modifying characteristics of ship voice print through employing nonlinear vibration isolation system and pays special attention to system dynamics at critical state as system changes stabilities, from stable to unstable, or vice versa...In this project, physical mechanism of nonlinear vibration isolation systems to alter structure of voice print of vessels will be investigated through analyzing effects of parameters, including bifurcation parameters and perturbation parameters, as well as system parameters, on system dynamics of nonlinear vibration isolation system model, and then finding out methods of predicting the stable boundary of nonlinear system. On the basis of the above analysis results，active control strategies are built to keep/change operating conditions. Finally,the performance evaluation of the control method which presents ability of nonlinear vibration system to change line spectrumsis considered...It is expected that results gotten in this project can give guidance to techniques of altering vessels voice print. Meanwhile, a general method to identification of the critical condition and active control of nonlinear systems associated with nonlinear vibration isolation system are attempted to be developed.

声纹是声纳对水下航行器进行探测和识别的主要依据。利用非线性隔振系统进入不稳定振动状态时其响应频谱发生突变这一特点，可以改变机械设备传递到船体的线谱特征，从而改变水下航行器的声纹，提高其声隐身性能。本项目将研究利用非线性隔振系统改变水下航行器声纹特征的方法，重点关注非线性隔振系统在分岔临界状态的动力学特性，探索非线性隔振系统改变低频线谱的物理机理。利用非线性动力学工具分析隔振系统自身参数及扰动信号参数与其隔振性能之间的关系，通过考虑各参数对系统输入/输出动力学的影响，建立非线性隔振系统稳定/不稳定边界的辨识方法，研究非线性隔振系统稳定/不稳定工作状态的主动控制方法，为水下航行器的声纹改变技术提供理论指导。同时，针对与非线性隔振系统相关的一类非线性系统，探索其临界状态辨识及主动控制的一般性方法。

声指纹是声纳对水下航行器进行探测和识别的主要依据。利用非线性隔振系统改变系统输出频谱的特性可以改变水下航行器的低频线谱特性，进而达到改变声纹的特性。本项目通过开展非线性隔振系统的动力学分析，建立了基于非线性系统稳定边界特性的辨识方法，为非线性隔振器实现低频线谱的主动调控提供理论指导。根据非线性隔振系统的试验研究，探明非线性隔振系统改变系统输出频谱结构的物理机理，为非线性隔振系统的工程应用奠定了基础。针对低频离散线谱抑制及调控中的稳定特性，边界动力学特性等科学问题，进行非线性系统动力学及振动控制等多学科的交叉研究，为提高水下航行器的声隐身性能，促进了水声对抗技术的发展。.本项目研究结果表明非线性隔振器可以有效抑制水下航行器的低频线谱，并且可以改变低频线谱的分布特性；通过在非线性系统边界附近，监测系统输出信号的幅值相对参数变化率及谱线峰值分布特性，可以提前辨识非线性系统的失稳方法。利用非线性隔振器改变水下航行器的声指纹特性，具有显著的科学意义和工程意义，对提高水下航行器的生命力具有一定的指导意义。