Kravchenko O. Adaptive spatial control of ultrasonic cleaning of products of complex configuration

The thesis is dedicated to the solution of the scientific problem of development and research on mathematical models and in the production process of the system of automated control of ultrasonic cleaning (UC) of products of complex configuration in order to increase its energy efficiency and the quality of the final result. In the first section, based on a review of literary sources, the process of ultrasonic cleaning is analyzed and unresolved issues in this area are identified. The influence of various factors allowing to optimize the cleaning process was analyzed and it was found that the automation of the process is one of the ways to increase its efficiency. The most critical thing is the lack of means that allow shaping control of ultrasonic cleaning according to the condition of the cleaned product. The solution to this problem was the use of three-dimensional fuzzy logic, which is inherently designed to control spatially distributed processes. In the second section, the construction of ultrasonic cleaning models for different physical cases (cleaning with a decrease in the density of pollution and a decrease in its thickness) and for products of different configurations is considered in order to determine the main patterns of changes in the ultrasonic response when the pollution of the product is reduced. It was found that when the product is cleaned, there is a change in the signal arrival time, as well as the maximum amplitude and the number of significant amplitude deviations. A method of forming an assessment of the state of the course of ultrasonic cleaning of a given area using a spectral decomposition by means of a fast Fourier transformation has been developed. The third section is devoted to the development of an efficient spatial control system based on fuzzy logic. To combine the advantages of such extensions of fuzzy logic as three-dimensional (allows to process spatial information) and interval (works well with information that does not have a clear expert evaluation), a controller based on three-dimensional fuzzy interval logic was developed. It is based on a fuzzy set that has an interval membership function and an additional spatial coordinate. The controller's work algorithm consists of traditional operations of fuzzification, output formation and defuzzification through expansion at the second stage due to spatial unification of information and dimensionality reduction. An algorithm was also developed to determine the control parameters for the technological capacity based on the ratio of the values of the intensities of the ultrasonic emitters obtained with the help of a three-dimensional fuzzy interval controller. In the fourth section, an algorithm for the formation of effective spatial control of the UC process was developed using ultrasonic sensors to determine the efficiency of the cleaning process in individual areas. On the basis of this algorithm, software was developed, with the help of which the cleaning process was simulated using various methods of processing input information and implementing the output control influence. Simulation of ultrasonic cleaning was carried out using the specified controller, first by completely fixing the change in the signal of ultrasonic responses after certain time intervals and using the method of evaluating the state of the cleaning progress described in the third section. In the first case, the energy savings due to the reduction of processing of only those areas that need cleaning amounted to 41 %, and in the second it was increased by another 6 %. This testifies both to the effectiveness of the proposed ultrasonic cleaning control system and to the expediency of using the method of evaluating the state of the cleaning process by analyzing ultrasonic responses. Simulations were also carried out using ultrasonic phased arrays as performing elements. The increase in the total acoustic pressure in the pollution zone was 40 % compared to the use of conventional ultrasonic emitters. The software was developed using the MATLAB and k-wave application packages.