一种基于新阈值函数的小波降噪方法在高速风洞中的应用

Application of Wavelet De-nosing Method Based on New Threshold Function in High Speed Wind Tunnel

为了解决传统阈值函数中抑制干扰与保留信号有效突变区域和信号高频细节之间的矛盾,提出一种基于新阈值函数的小波降噪方法。介绍了传统小波阈值函数降噪方法,根据小波阈值降噪方法的特点构建一种新阈值函数,并进行风洞试验验证,用硬、软阈值以及新阈值方法对X元信号进行处理,将经过不同降噪方法处理后得出的CL-a曲线进行对比。试验结果表明:该方法与传统函数方法相比具有明显的优越性,一方面其处理后的试验数据结果与阶梯试验数据吻合度更高;另一方面该方法在抑制干扰影响的同时,能够有效捕获到飞行器模型在突变区域的有效高频信号。

This paper puts forward a de-noising method based on new threshold function for continuous acquisition signal of wind tunnel to solve the traditional method＇s conflict between noise pollution control and high frequency signal details retaining. Traditional wavelet threshold function noise de-noising method is introduced, according to the characteristics of the wavelet threshold de-noising method, a new threshold function has been constructed. Different methods have been used to de-noising the signal X, the CL-a curves were compared. Test results shows that the new threshold function has many advantages over traditional function, it has the higher similarity with the original signal. At the same time, by using different methods to deal with the calibration model, it is showed that the new threshold function method fits the step test better, it has a good de-noising performance and also can get the none-linear aerodynamics of the aircraft model or the non-stable character of the mutation signal.