Research And Application Of Electrical Capacitance Tomography Multilayer Sensor Design And Image Reconstruction

Electrical Capacitance Tomography(ECT)is an important industrial control method.Its principle is to scan the space containing conductive materials from multiple angles through alternating excitation electric fields.The conductive materials are excited in the electric field.Induced charges are generated below and interact with the original electric field.Through the evenly distributed detection electrodes around a closed pipe or container,the measured capacitance data can be collected from different directions,and then the capacitance value and sensitivity matrix can be used to reconstruct the material distribution image.The key technologies of the ECT system include the optimal design of sensors,the design of data acquisition circuits,stream pattern recognition and image reconstruction.ECT technology cost is low,not universal,directly obtain process parameters,widely used in industrial production.It is an ideal method for industrial real-time detection.An optimization algorithm for sensor design and image reconstruction in ECT system is studied.The main tasks are as follows:In terms of sensor design,the finite element analysis method is used to establish a 3-layer 12-electrode sensor.The physical field simulation experiment is carried out with Maxwell through the model perturbation method,and the sensor electrode plate angle,tube wall thickness and excitation mode are changed to analyze The capacitance value of the empty and full tubes and the sensitivity matrix changes,and the influence of the physical structure parameters of the sensor on the sensor measurement is obtained.At the same time,on the 3-layer 12-electrode sensor model,the adjacent double electrodes of the same layer are used as excitation electrodes,and the comparison is made in different excitation modes.The data acquisition accuracy of the multi-layer sensor and the variation range of capacitance value are reduced,thus obtaining the optimal solution.The experimental results show that the optimized sensor increases the amount of data acquisition,the collected signal is stronger,the sensitivity matrix changes more obviously in the object field,and the image reconstruction accuracy is significantly improved.In the aspect of image reconstruction,aiming at the problem of many iterations in iterative algorithm,a design pattern based on regularization iterative correction is proposed.slow convergence speed,smooth effect on the interface of the medium and difficulty in selecting the iteration step length.The algorithm adds a regularization term to the ECT image reconstruction algorithm,adopts the method of adaptive weight coefficients,and uses four typical ECT flow pattern tomographic interfaces as the standard flow pattern.Improve the convergence of algorithm reconstruction and ensure the timeliness of image reconstruction.speed to improve image reconstruction quality.Experiments show that the optimized image reconstruction algorithm is superior to the previous repeated algorithms in terms of reconstruction speed and accuracy.