基于双调制随机共振的涡街信号检测方法

Vortex Signal Detection Method Based on the Dual Modulated Stochastic Resonance

研究一种用于涡街流量计涡街频率测量的随机共振信号处理方法。探讨了信号与双稳系统的阈值和克莱默斯逃逸率之间的关系,通过外加幅值和频率可调的信号进行双重调制,实现信号与双稳系统的匹配,数值仿真表明该匹配方式是可行和有效的。针对涡街信号,提出基于标准差的调制参数选取方法,该方法利用涡街信号特征,通过信号标准差估计管道内流速,缩小了调制参数的选取范围,提高了信号与双稳系统匹配的效率。实验结果表明,利用标准差选取调制参数对涡街信号进行调制,可以有效地使涡街信号,特别是弱涡街信号产生随机共振,进而检测到涡街频率,实现流量测量。

A signal processing method based on stochastic resonance applied to the vortex shedding frequency mea-surement of vortex flowmeter is studied. The relationship between signal and bistable system parameters such asthreshold value and Kramers rate is discussed. The input signal is dual modulated by the signal with adjustable am-plitude and frequency to realize the matching between signal and bistable system. The simulation results manifestthat the matching method is feasible and effective. The method specific to vortex signal is proposed to selecting mod-ulation parameters based on the standard deviation. The vortex signal feature is used to estimate the flow velocityand reduce the modulating parameters scope by standard deviation. Therefore,the matching efficiency between sig-nal and bistable system is improved. The experimental results indicate that the modulated method can make the vor-tex signal,especially the weak vortex signal generate stochastic resonance and effectively obtain the frequency ofvortex shedding for flowrate measurement.