摘要
汽车在高速行驶时,轮速传感器信号的信噪比降低以及由轮速信号计算数据的发散性是汽车安全有效控制的难题。将轮速传感器信号用快速傅里叶变换(Fast Fourier transform,FFT)到频域,在频域里研究真实信号和噪声的波形特点。在频域里,真实信号频域范围很窄但能量很强;而噪声频率范围很宽但能量很低。据此提出用FFT与傅里叶逆变换(Inverse fast Fourier transform,IFFT)处理轮速信号的新方法。将采集的轮速信号进行FFT变换,在频域里保持信号的能量不变,用曲线拟合的方法将噪声的能量进一步降低。经如此频域'滤波'后,再通过IFFT逆变换获得时域的真实信号。经过此FFT/IFFT处理后的轮速信号的信噪比(Signal-to-noise ratio,S/N)显著提高。在间接式轮胎气压监测系统(Tire pressure monitoring system,TPMS)的实车道路试验中,分别对轮速信号进行电路滤波、卡尔曼滤波与FFT/IFFT滤波效果进行比较,FFT/IFFT处理轮速信号能有效消除噪声,效果最好。
When a car is running at high speeds, the signal-to-noise ratio from the wheel speed sensors is reduced, and the data calculated by the wheel speed signal are emanative, which is the problem for the safety and effective control of a car. The wheel speed sensor signals are transformed into the frequency domain using fast Fourier transform（FFT）, and the characteristics of the waveforms of the true signal and noise are studied in the frequency domain. The frequency range of true signals is very narrow and its energy is very strong, but the noise spectral range is very width and its energy is very weak. According to this difference, a new method is given to process wheel speed signals using FFT and IFFT. Wheel speed sensor signals are transformed into frequency domain with inverse fast Fourier transform（FFT）. In frequency domain the energy of signals keeps unchanged, and that of noise is reduced with the method of polynomial fitting. After so“filtering”processing, the curve of spectrum wave is transformed back into time domain with IFFT to obtain real signals. The S/N of signals is significantly improved with this FFT/IFFT processing. In tire pressure monitoring system（TPMS）test in road, the effects of three filtering methods are compared which are electronic current filter, Karman filter and FFT/IFFT filter. The test indicates that the method of FFT/IFFT filter can get rid of noise efficiently, and its effect is best.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第16期155-161,共7页
Journal of Mechanical Engineering
基金
国家自然科学基金(51175450)
河北省自然科学基金(E2012203046)资助项目
