Vol 30, No 10 (2024)

This paper considers the problem of approximating a function from observations in the case when the object under study contains mutually ambiguous characteristics in its description. This formulation is essential in identifying and controlling systems of the Wiener and Hammerstein class, in which nonlinear processes can be represented as a sequential connection of linear dynamic and nonlinear inertia-free blocks. Often elements such as hysteresis loop, backlash and others are used as nonlinear blocks. These elements are mutually ambiguous mappings. In connection with the transition to automated digital production, which is controlled in real time by intelligent systems rather than humans, nonlinear dynamic processes are found everywhere. The complexity of solving the problem lies in the lack of sufficient a priori information about the parametric structure of the model of the process under study. The paper proposes some modifications of the nonparametric estimation of the regression function, allowing for the modeling of mutually ambiguous mappings. Some fragments of numerical studies are presented that show acceptable results in terms of reconstruction accuracy.

During the operation of a complex machine or device, it is necessary to perform complete or partial disassembly of the product and its individual components and assemblies. Disassembly operations are required for repair, maintenance and disposal of technical system components at the end of their service life. Modern technical systems can consist of several thousand (or more) parts and components. Therefore, it is necessary to use modern computing and design automation tools to plan disassembly processes and operations. The sequence of disassembly and the content of disassembly operations largely depend on the mechanical structure of the product. To model the mechanical structures of complex products in CAD-systems, various graph and network models are mainly used. The paper gives an overview of the most popular models of this type. The main carrier of information about the mechanical structure of a product is the so-called liaison graph. The review considers design procedures for synthesizing disassembly processes using the liaison graph. Procedures of expert ordering and procedures based on cuts in the liaison graph.

The article is devoted to define requirements and discover specific features for domestic standard cell and I/O libraries characterization EDA tool. A general structure of the library characterization system is presented. The basic requirements indicted for the system are considered and analyzed in the article. A comparative analysis of correspondence to these requirements for domestic and foreign characterization tools is done. The specific features the domestic library characterization system should satisfy are formulated. Among the main features the following are outlined in the article: compatibility and support of domestic OS, support of well-known foreign and domestic Spice-simulators, Russian language support for documentation, scalability, ensuring confidence of the output data. A brief review of typical tasks, intrinsic for characterization tool development and corresponding algorithms, required for its resolving is given. The following issues along with appropriate proposals for its solution are mentioned: automated definition of optimal input waveforms for sequential cells initialization, searching for maximum capacitance load for the cell, setup and hold parameters calculation for sequential cells, method of optimal output current PWL approximation for CCS parameters calculation. As a conclusion of the investigation the current status of domestic characterization systems development is analyzed. In the outcome a problem of domestic library characterization tool that aligned with all the requirements and support the specific features defined above has been raised.

The problem of tracking an underwater pipeline (UP) is considered in the context of an inspection mission. It is assumed that the diameter of the cylindrical pipe is known. To solve this problem, a tracking method is proposed, based on searching and calculating the center line of the UP, and determining the relative position of the autonomous underwater robot (AUV) and UP in the coordinate system of the AUV camera. Unlike well-known analogues, in which the solution is based on recognizing and constructing the boundaries of the UP in images, the proposed method searches for the true position of the center line of the UP on a set of possible options by checking their veracity. Possible options for the spatial position of the search centerline of the current UP section are generated by varying the direction of the beam in the horizontal and vertical plane. The starting point of the ray is the end point of the centerline of the previous section. The veracity criterion is to check that the 3D point features constructed in the scene belong to the cylindrical surface of the UP. The generation and matching of point features in images of a stereo pair is carried out using the SURF detector. The choice of the correct direction of the center line of the current UP section is ultimately made by voting. The end point of the center line of the current section is determined taking into account the calculated common visibility area with the previous section of the UP. To evaluate the effectiveness of the method, computational experiments were carried out on virtual scenes. The effectiveness was assessed by the accuracy of UP localization (in the AUV coordinate system) and by the speed of calculations in comparison with: a) the first version of this method, based on the use of a vectorized form of images; b) analogues using the Canny and Hough Transform detectors. The stability of the method to the accumulation of navigation accuracy errors during long-term tracking of UPs was also assessed.

The article examines spatial isolines construction based on data on an irregular grid. In particular, a possible solution to the problem of contour breaks is explored. Measurements of the magnetic field parameters taken from variation stations are used as data. The paper presents a description of the algorithm for constructing isolines and describes the software system that implements this algorithm. The results of system performance testing are given in the last chapter.