Moscow Aviation Institute

All modern aircraft are designed in accordance with the requirements of the certification basis (CB). FAR.25 contains numerous clauses that impose requirements on the strength of the main landing gear (MLG) hinge structure. In this paper, two typical landing gear hinge configurations were identified, an analytical analysis was conducted, and the main analytical formulas for determining reactions at the landing gear hinge nodes were derived, with the goal of creating a simple mathematical model. Trivial algebraic methods, such as solving statically indeterminate frames, were used to determine the main reactions. This model allows for the creation of a model for optimizing the landing gear hinge design, the main goal of which is to identify hazardous areas that do not meet the requirements for safe MLG failure when the airframe load is exceeded. At the same time, this mathematical model is planned to be used to determine reactions for the design of durable structures in the early stages of aircraft design.

The work is devoted to numerical simulation of the problems of flowing around moving bodies. The main equations of heat and mass transfer of a viscous compressible gas are provided. To describe the flow over the object with moving boundaries, a motion velocity vector is introduced into the numerical scheme of the finite-volume method. The computation method on meshes with overlapping (or overset grids) was considered as a simulation approach. Key stages of the proposed computation technology are given. To reduce the computational complexity of generating an interpolation stencil, the use of hierarchical data structures is proposed. Reconstruction methods described in the work are based both on well-known algorithms for interpolating computed values, and original methods based on the use of gradients of computation fields and on the use of a four-point stencil. To demonstrate the operability of the algorithms, the problem of subsonic flow around the two-link airfoil section and the task of separating the store from the wing with the pylon in the transonic flow of a compressed gas are considered. The primary objective of this work is to develop an efficient numerical model based on unstructured overset grids for solving applied problems of fluid-moving body interaction in the interests of the aviation industry. The analysis of the obtained results for the separation problem has shown the advantage of the proposed reconstruction approaches with respect to standard interpolation methods, which made it possible to increase the accuracy of prediction of aviation angle dynamics by more than 15

The paper proposes an approach for fast tuning the nonlinear attitude control system applied for a quadcopter. First, a mathematical model of quadcopter’s motion is estimated by a simple identification process using a low-cost test bench. After that, the controllers’ parameters are computed via optimization-based synthesis using simulation-in-loop framework. The proposed approach therefore does not require the development of a complex mathematical model built on the theories of aerodynamics, flight dynamics and DC motors, as well as geometry and mass/inertial properties of a quadcopter. There is also no need to apply any algorithm for nonlinear control system analysis. Due to its simplicity, the proposed approach can be used for quick synthesis of new control systems or adjusting the existing ones. The adequacy of the proposed approach is confirmed by bench studies of identification accuracy and control performance. Besides this, the paper also firstly describes the mathematical principle of the square-root controller implemented in well-known flight controller software like Ardupilot.

An Erratum to this paper has been published: https://doi.org/10.1134/S1063785026010013

Today, as digitization continues to develop, the success of industrial enterprises depends on their ability to change. To ensure their global competitiveness, they must undertake comprehensive analysis of key trends in the development of industrial enterprises in such conditions. That may be based on economic and statistical analysis, as well as elements of qualitative and systems analysis for thorough assessment of the results. In this article, a definition is proposed for the key trends in the development of industrial enterprises in an era of digitization, and appropriate tools are noted. Directions for industrial transformation to ensure flexibility, productivity, and competitiveness in a digital economy are identified.