The Development And Experimental Verification Of Wireless Impedance Tomography System For Centrifuge Particle Distribution Detection

The centrifuge is a separation machine that separates particles of different properties.In order to improve the separation efficiency,a technique capable of imaging the particle distribution in the centrifuge is necessary.By contrast,this paper selects electrical impedance tomography(EIT)technology,which is characterized by low equipment cost,real-time,non-invasive,visual,and high resolution.EIT technology was originally applied in the detection of biological tissues,but in industrial applications,imaging hardware systems are required to be miniaturized,portable,and wirelessly transmitted.Due to the consideration above,an EIT system based on Red Pitaya STEMlab was developed to identify the location of the substance and two different substances.The design of the EIT system consists of two parts,the hardware part and the software part.The purpose of the hardware part is to measure the voltage of the electrodes in the physical field.The modular design of harrdware system mainly includes the Red Pitaya STEMlab board,voltag e-controlled current source module,analog multiplexer module,8-electrode sensor sink an,d PC.The software part mainly solves the positive and inverse problems of the EIT system.The positive problem is the problem of solving the sensitive matrix.The inverse problem is to inversely calculate the distribution of the conductivity in the physical field according to the voltage data measured by the sensitive matrix and the hardware part,so as to reconstruct the image according to the calculated conductivity distribution.In this paper,image correlation and voltage error are selected as the image reconstruction quality evaluation standard.The image reconstruction algorithm uses GVSPM and Tikhonov regularization two image reconstruction algorithms.Through simulation and experimental verificati,on,the image reconstruction quality of Tikhonov algorithm is better.In this paper,firstly,the experiment of single-component distributed imaging is carried out to verify that the system can perform the position of the material in the clear imaging area in the frequency range of 200 KHz,and meet the measurement requirements of the EIT system for the industry.Secondly,the electrochemical impedance spectroscopy(EIS)analysis method was combined with EIT simulation.The simulation results show that the maximum difference frequency between each substance is the image reconstruction frequency of its corresponding substance,and then multi-frequency image superposition is performed to obtain the final two components distribution image.Finally,the experimental results show that the method is feasible and can be used in multi-component distribution imaging detection.