Test And Analysis Of Electric Slides' Comfortability Based On Cyclic Spectrum Density

With the development of the automobile industry and the increasing demands on the electrically operated chairs in our country, it is becoming more and more important to make some researches on their vibration characteristics as well as comfortability. In this paper, a few statistical methods for evaluating the electric slides'vibration performance are introduced, and some researches are carried out to extract the characteristic signals that affect human comfort.First, the electric slides'mechanisms about the impact and vibration are analyzed according to their mechanical structures, and then some common evaluation statistics are introduced, including the vibration characteristics and comfortablility. Because the signals at different frequencies have different effect on the human body, a weighting filter is used for the acquired signals. As a result, a sensitive area can be obtained from the amplitude-frequency response, and the time-averaged weighted acceleration values and levels are also calculated to evaluate the impact of vibration on the human body. Since some noise exists in the collected vibration signals, it is necessary to eliminate the noise effectively before further signal processes. In this paper, Redundant Second Generation Wavelet Denoising is used to eliminate the noise that exists in the collected vibration signals and retain the tremendous impact signals that have a great impact on human comfortability.The estimation of Cyclic Spectrum Density are carried out after preprocessing the collected vibration signals, and then the slices are analyzed to extract the characteristic signals having great effect on comfortablility. However, because of low frequency resolution among the estimation of Cyclic Spectrum Density and the frequency spectrum divulging phenomenon and the stockade effect of FFT, it is so hard to get the accurate carrier frequencies as to affect the accuracy of feature extraction and even have a large deviation. Owing to the impact response signals existing in the collected vibration signals, Laplace wavelet correlation filtering method is employed to obtain the accurate carrier frequency in this paper. Considering the complexities of the actual signals, the EMD method is first used to decompose the signals after preprocessing; and then the correlation filtering is employed to find the carrier frequencies via Laplace wavelet; Finally, the slices of Cyclic Spectrum Density are analyzed, the characteristic signals obtained effectively.At last, the hybrid programming is presented with the combination of Visual C++ 6.0 and Matlab 6.5 to build a virtual platform to test and analyze characteristics and comfortability of the electric slides, and an embedded industry computer is used to carry out data acquisition, signal processing and analysis as well as real-time data graphics and testing results demonstrated, which are similar to instrument's testing functions. Meanwhile, considering the networking of factory production and the unification of criteria, a database system is constructed based on SQL Server 2005.