Study On Adaptive Control For Electro-magnetic Vibroseis Sweeping Signal

With the development and the progress of our country’s economy,people’s demand for resources is becoming bigger and bigger,but limited to many resources regeneration cycle is long and the resource’s exploration speed is much lower than the consumption speed,so promoting the reform of technology and the research of the newer geological exploration equipment become the attention hot spot. As one of the most effective way to prospecte for mineral resources,Seismic exploration technology has been widely concerned at home and abroad. Vibroseis as one of the main eccitation source in seismic exploration,the quality of the excitation signal affects the precision and accuracy of seismic data directly. As a kind of high frequency vibration excitation source,the electro-magnetic vibroseis has been widely applied in the field of shallow geological exploration,however,the research of the electro-magnetic at home and abroad is late and the development of it is slow.In addition,combined with the unique structure of the electro-magnetic vibroseis and the disadvantage of the open loop control makes the existing electro-magnetic vibroseis excitation sweeping signal out of control,and the output of vibroseis system signal attenuation is serious with the increase of vibration frequency,unable to meet the requirements of the precision of the current seismic exploration.In order to solve the control problem of the electro-magnetic vibroseis sweeping signal,this article takes PHVS-500 type electro-magnetic vibroseis as the research object,analyses the deficiencies of the open-loop control system based on the existing hardware structure,and proposes an adaptive control scheme of the electro-magnetic vbroseis sweeping signal. In this scheme,computer control unit is the key part of control system,the close loop control system is composed of sweeping signal generating module, signal processing system, the electro-magnetic vibrator and data acquisition module. In the process of implementing the adaptive control scheme,first of all,we analyze the system structure of the electro-magnetic vibroseis,using the system identification method which based on recursive extended least squares to calculate the structure and parameters and determine the mathematical model expression of the vibroseis system,and analyzes the identification result. Then we put forward the Narendra stable adaptive control scheme based on the theory of the Lyapunov by using adaptive control theory on the basis of electro-magnetic vibroseis system mathematical model,give the detail mathematical derivation of design method of the controller,and apply to the electro-magnetic vibroseis system,achieve electro-magnetic vibroseis sweeping signal adaptive control at last,provide a new method for the development of system control technology of the electro-magnetic vibroseis.Through the simulation analysis on the performance of the Narendra stable adaptive controller and contrastive analysis on the actual sweeping signal of the electro-magnetic vibroseis system before and after the adaptive control,verify the feasibility and effectiveness of the proposed scheme in this paper. Finally,this paper concludes the full text,and discussion and prospects are made on the application of adaptive control technology on the electro-magnetic vibroseis system.