基于混沌理论的涡街微弱信号检测方法研究

针对涡街流量传感器在小口径、低流速下信号微弱,易被强噪声淹没而难于提取的特点,提出了利用Duffing振子检测微弱信号的方法.通过仿真对涡街信号中含有白噪声以及谐波干扰的情况进行分析,仿真和实验均表明:这种基于混沌理论的微弱信号检测方法对涡街信号中较强的白噪声以及频差较大的谐波干扰具有很好的免疫力,并且通过计算最大Lyapunov指数的波动频率能够准确估计出涡街有用信号频率,实现低流速下涡街微弱信号检测.

Study of weak vortex signal detection based on chaos

The vortex signal is weak and easy to be submerged by high level noises when the vortex flow sensor measures low flowrate in a small caliber. It is difficult to pick out the useful vortex frequency. In order to solve this problem, a new method based on Duffing oscillator is proposed to detect the weak vortex signal. The vortex signal with high level white noise and harmonic disturbance is analyzed by simulation. The simulation and experiment results indicate that the method based on chaos has a good immunity to white noise and harmonic disturbance with big frequency difference in vortex signal. And the useful vortex frequency is estimated correctly by calculating the frequency of maximum Lyapunov exponent. In this way, the weak vortex signal can be detected in low flow rate.