Inspection and analysis of the walls of fluid filled tubes by active electrolocation: a biomimetic approach

Abstract

During their nocturnal activity period, weakly electric fish employ a process called "active electrolocation" for navigation and object detection. They discharge an electric organ in their tail, which emits electrical current pulses, called electric organ discharges (EOD). Local EODs are sensed by arrays of electroreceptors in the fish's skin, which respond to modulations of the signal caused by nearby objects. Fish thus gain information about the size, shape, complex impedance and distance of objects.Inspired by these remarkable capabilities, we have designed technical sensor systems which employ active electrolocation to detect and analyse the walls of small, fluid filled pipes. Our sensor systems emit pulsed electrical signals into the conducting medium and simultaneously sense local current densities with an array of electrodes. Sensors can be designed which (i) analyse the tube wall, (ii) detect and localize material faults, (iii) identify wall inclusions or objects blocking the tube (iv) and find leakages. Here, we present first experiments and FEM simulations on the optimal sensor arrangement for different types of sensor systems and different types of tubes. In addition, different methods for sensor read-out and signal processing are compared.Our biomimetic sensor systems promise to be relatively insensitive to environmental disturbances such as heat, pressure, turbidity or muddiness. They could be used in a wide range of tubes and pipes including water pipes, hydraulic systems, and biological systems. Medical applications include catheter based sensors which inspect blood vessels, urethras and similar ducts in the human body.

Characterization of a bionic electrolocation sensor using finite element modeling

“…However, the precise diagnosis and explicit characterization of plaques is still a big challenge in the medical field. The concept of a multielectrode electrolocation sensor based on the principle of active electrolocation of weakly electric fish for coronary diagnostics has been proposed before [1,2]. Weakly electric fish such as Gnathonemus petersii use Mormyromast electroreceptor organs to sense self emitted electrical signals (electric organ discharges, EOD) during active electrolocation.…”

“…Our goal is to use active electrolocation to determine the conductivity and the dielectric properties of coronary plaques with a multi-electrode sensor and thus characterize different plaque types. Our previous studies have shown [1,2] that it is possible to differentiate the material properties and different size of the targets with commercially available four-electrode catheter sensors based on the electrolocation principle. In this paper, we introduce a novel design of a multi-electrode catheter sensor.…”

A multi-electrode biomimetic electrolocation sensor

“…In our earlier studies, we have already explained the physical phenomenon of an active electrolocation sensor catheter measuring within an insulating tube [3][4][5]. In these previous experiments, glass tubes were used instead of Plexiglas tubes.…”

“…After validating the modeled data, we analyzed the effect of the sender to receiver distance on localization parameters of the electrical image. Our earlier studies showed that the sender to receiver distance is a significant parameter for extracting data from the electric images [3][4][5]. When the sensor was moved inside the glass or Plexiglas tube in the aquatic bath, a first peak is observed when the sender approaches the target.…”

“…In our previous studies we have shown that by learning from natural models such as the weakly electric fish Gnathonemus, petersii, it is possible to employ an active electrolocation method to distinguish between the electrical properties of different medical materials, i.e. to differentiate between various types of coronary plaques [3][4][5].…”