The Theory And Method For The Mechanical Fault Signal Detection Based On Stochastic Resonance

Based on the theory of stochastic resonance, this paper has designed a parameter adjustablestochastic resonance system. Through the modeling, the calculating, the simulation experiments andthe circuit design, it is confirmed that the system can detect the large-frequency weak signal in thebackground of strong noise valid. Based on the DSP technology, we have designed the hardwarecircuit of the self-adaptive stochastic resonance system which can automatically adjust theparameter of the system. The paper was supported by the national science fund" The research ofmechanical fault diagnosis based on the nonlinear theory in the weak signal detection and treatmenttechnology (50875070)".The main contents of the full paper are done as follows:On the basis of extensive reading the literature in the domestic and foreign, Chapter oneintroduces the development dynamics and research status about stochastic resonance theory andproposed the problem of the paper need to solve. In the chapter, we also have sure the main contentof the research, the method and its innovation points of the paper.Based on the Foke-Planck equation, Chapter two generally introduces the basic theory ofstochastic resonance, meanwhile it analysis the dynamic characteristics of the typical stochasticresonance system, the reasons and the conditions of producing stochastic resonance and themeasurements of using the principle of stochastic resonance, the relationship between the noise andthe weak signal.Chapter three has proposed a new way to research the stochastic resonance. Based on thequalitative analysis of the linear system naturally, transition to the first order non-linear system, wecan get the general characteristic of the nonlinear system, lead out the essential factor of thestochastic resonance, in order to research the way to detect the weak signal under the strong noisebackground in stochastic resonance.Based on the bistable system stochastic resonance and the modulated stochastic resonancetheory, Chapter four has proposed a closed-loop design of modulated stochastic resonance, doingthe simulation about the single frequency signal and multi-frequency harmonic signal, and design acircuit module, which also achieved experimental verification at last.Chapter five has introduced the related concepts of the adaptive stochastic resonance theory andcombining with adaptive parameter adjustment principle designed an adaptive modulate stochasticresonance system based on DSP technology. Though the analysis of the characteristics of DSP, wehave studied the hardware circuit and software system of the adaptive modulate stochasticresonance system based on TMS320F2812.Chapter six tells about the superiority and insufficiency of the theory in this paper, and then makes some prospects for further research.In this paper, as the basic application research on stochastic resonance theory, through thequalitative analysis of the linear system, we bring in the qualitative of the non-linear system, welearn the essential properties of the stochastic resonance. As the low-to-medium frequency periodicsignal and multi-frequency harmonic are more common but difficult to be detected in engineeringpractice, with the theory of modulated stochastic resonance, transform various frequencycomponents into a small parameter signal which can meet the adiabatic approximation condition,and doing the simulation about the single frequency signal and multi-frequency harmonic signal.with the digital signal processing as the guiding ideology, studied a closed-loop stochasticresonance hardware circuit and software system, will surely provide a reference for futureapplications.