The Trispectrum Analysis Of The Magnetorheological Dampers

Magneto-Rheological(MR) damper is one kind of new integration of machinery installment. It can provi de continuously the invariable damping force under the outside magnetic field, make revolutionary change to some traditional damping technology, which has significant advantages as following: simpler structure, quicker response, better controllability and intellectual technology.The MR system is a nonlinear and time-variant system with multiple inputs and multiple outputs. Traditional signal processing method is not suit for analyzing the MR damper having nonlinear and non-Gaussian characteristics. In this paper, a new method based on the analysis of trispectrum was introduced into the research of MR fluid to extract the nonlinear and non-Gaussian information and analyze its nonlinear coupling and nonlinear system.Firstly, the MR vibration testing platform used to pick-up vibration signals applied to trispectral analysis, was designed based on virtual instruments. It was shown that the experimental platform is versatile, on which many experiments of electromechanical engineering can be carried out easily and expediently.Secondly, This paper was described some of the basic principles of HOS(higher-order spectra), demonstrating how they can yield information which is unavailable through examination of third-order statistics, such as the spectrum or correlation function, the programs of the bispectrum analysis . Relations between electric current, frequency and the damping effect were researched statistically by spectral slices. The MR damper shows nonlinear characteristic distinctly.Finally. the concept of the Correlation-dimension for further demonstrate the superiority in obtaining characteristic information of signal of a nonlinear MR system was introduced, which is used in all kinds of spectrum slices, as the trispectrum slices, bispectrum slices and the power spectra, then the values of Correlation-dimension of the given spectra are reduced gradually in order. Such a decrease in the correlation dimension strongly indicates that the trispectrum can obtain more characteristic information of signals of a nonlinear MR system.