Research On The Simulation Method Of Underwater Active Electrolocation System Base On IP Effect

The active electrolocation method is invented by simulating that a kind of weakly electric fish detect target. It can generate a low frequency electric field by its electric organ discharges(EOD), and can sense the change of electric field in surrounding area by its electroreceptors. This function of weakly electric fish is called active electrolocation. In previous experiments, the amplitude information-frequency characteristics(AIFC) for active electrolocation system has been studied, and the Detect frequency dead zone(DFDZ) and Frequency inflection point(FIP) phenomena of AIFC for active electrolocation system has been found. These phenomena cannot be explained by the Maxwell electric theory. To understand the physical mechanism of underwater active electrolocation. Inspired by geophysical exploration, the finite element model and equivalent circuit of active electrolocation system based on IP effect were built in this paper. All of our works can be concluded as following four parts:1.Firstly, based on the Maxwell electric theory, we set up a mathematical model and a finite element model of the 2D active electrolocation system.2.Based on the finite element model, large numbers of calculations are carried out to detect the ?20mm×40mm copper cylinder, aluminum cylinder, iron cylinder and plexiglass cylinder. The calculations indicate that: 1) the finite element model of active electrolocation system based on the Maxwell electric theory can locate the target; 2) comparing the locating carves at several frequencies, we found that the locating carve of active electroclocation is unrelated with the frequency. So, the electric field distribution of the active electrolocation system cannot be described by the Maxwell electric theory.3.The equivalent circuit model of the active electrolocation system based on the IP effect and the Maxwell electric theory was built. The IP effect is fitted by the Cole-Cole model in the equivalent circuit model. By analyzing this model, we can found that: 1) the amplitude of the signal at electroreceptors is unrelated to the frequency of the exciting signal in free water area; 2) But the amplitude of the signal at electroreceptors varies with the frequencies in the object area. These can be used to explain the DFDZ and FIP phenomenon of AIFC for active electrolocation system.4. A new finite element model of the underwater active electrolocation system based on the IP effect and the Maxwell electric theory was developed. The simulation results of this new model display that: 1) the underwater active electrolocation system can be simulated by the new finite element model of coupling the Cole-Cole model and ideal electromagnetic theory; 2) the DFDZ and FIP phenomena of AIFC for underwater active electrolocation system varies with different targets.To sum up, the finite element model of underwater active electolocation system based on the IP effect and the Maxwell electric theory can locating the target and finding the material properties of the conductor targets.