Research And Application On Parameters Sensitivity Of Stochastic Resonance For Weak Signal Detection

The working mechanism of stochastic resonance weak signal extraction is to enhance the transmitting capability of signal in specific nonlinear systems by using the stochastic resonance between the noise and the signal.The emphasis of the thesis is to extract the weak signal from strong noise background based on stochastic resonance technology.Based on previous explorations on stochastic resonance theory of weak signal detection, the synergistic effect among bistable stochastic resonance systems, noise and signal are studied systematically. With periodic signal and the non-periodic signal as inputs, the influences of structural parameters of the bistable system, signal frequency and noise intensity on the stochastic resonance effect are analyzed. Based on the research of bistable system, the monostable approximation model is put forward and the possibility of the enhancement on the weak signal transmission capacity is pointed out in monostable approximation system.The application basis of researches is the signal transmission in short drill string of the rotary steering drilling system. The advantages and disadvantages of underground communication methods based on electromagnetic wave and acoustic wave are compared. The acoustic wave communication is selected as the research object of this thesis. The working principle of acoustic communication in the short distance drill string between the stable platform and measure while drilling is studied, and the transmission model of the acoustic wave communication is obtained. Based on experiments, the transmission model of acoustic wave communication in short drill is established, in which the input signal can satisfy the requirements of stochastic resonance weak signal detection method. With Langvein equation, the stochastic resonance system model for underground acoustic communication is established. Combined with the results of the sensitivity study on parameters of stochastic resonance weak signal detecting system, appropriate parameters are selected. Finally, the frequency of the signal to be measured can be achieved. Achievements in this thesis have a good application prospect in the rotary steering drilling system.