Analysis of the Factors Affecting the Instrumentation of the Technological Process of the Activated Carbon Material Production

The article discusses significance of the development of activated carbon materials with a high specific surface area and high porosity. The features of the course of chemical activation and the factors influencing the characteristics of the obtained material have been established. The main stages of the activation of the carbon material, including the preliminary raw carbon material carbonization, its alkaline activation, and the post-processing of the created material, have been determined. The mutual influence of temperature and flow rate of an inert gas on the characteristics of a carbon material obtained with a BET specific surface in the range of 2550–2700 m2/g is experimentally investigated. The analysis of the obtained results has been carried out. Recommendations are given for reducing ambiguity and uncertainty during the transition from laboratory research to pilot production. The resulting activated carbon material can be used as a sorbent in gas purification systems, gas accumulators and for solving various environmental problems.

Topological Optimization of the Strength Element of the Aircraft Compartment Made of Metal-Matrix Composite Material

At present, in order to increase the weight efficiency of parts and structures of promising aircraft and rocket-space vehicles, various types of additive technologies and topological optimization methods are being actively introduced. Their purpose is a significant reduction in time and financial costs in the manufacture and creation of fundamentally new geometric solutions. The article considers approaches to selecting the geometric parameters of the strength elements of the flight vehicle body made of a metal-matrix composite material based on VT6 titanium alloy, reinforced with a finely dispersed silicon carbide powder, which is produced by direct laser growth technology. On the basis of numerical simulation, the dependences of the metal-matrix composite material physicomechanical and thermophysical characteristics on the volume fraction of silicon carbide have been determined. It was found that the use of a metal-matrix composite material and the optimization of geometric parameters with adaptation to the direct laser growth technology allows reducing the weight of the strength element of the flight vehicle body by more than 30% (depending on the overall dimensions).

Simplest Flow Queuing Models for LEO Satellite System

The relevance of the work is associated with the active deployment of low-orbit communication systems and the expansion of research in the field of corresponding satellite systems. A promising low-orbit communication system based on relay satellites with the function (RSRFs) of routing message packets is considered. The low earth orbit communications systems use the BGP protocol and the AAA functionality at the ground station. For assessing the characteristics of RSRF inter-satellite paths, a scenario was created for the message packets arrival from a group of inter-satellite paths to one subscriber path. The corresponding analytical models have been developed using the mathematical apparatus of queuing systems with the simplest flows of requests and exponential distribution of the service time. The RSRF characteristics of a promising low-orbit communication system are predicted. It is proposed to make the mathematical apparatus of analytical models more complicated to take into account the dynamics of displacements and failures of the RSRF in a low-orbit communication system.

Dynamic Calculation of Electric Propulsion Motor Tandem Rotors

The article presents the results of modeling the dynamic response of the tandem rotors of ice-class vessel electric propulsion motors under extreme operating conditions. The loading of rotors by torques in combination with vibration transmitted through the supports to the electric motors is considered as an external non-stationary action. A method for constructing a three-dimensional finite element model of the structure under study by fragmentary assembly has been developed on the basis of the ANSYS Mechanical software package. A scheme of elastic-compliant 3D-links allowing simulating the reciprocating-rotational vibrations of a tandem of rotors is presented. A test example is used to verify the proposed mechanical-mathematical model of the torsion system. Based on the calculated data, the analysis of the dynamic parameters of the tandem rotors is performed for the most unfavorable operating scenarios.

Development and Analysis of a Parallel Structure Mechanism with Slotted Arcuate Guides and a Constant Entry Point

The development and study of new mechanisms of a parallel structure ensuring the constancy of the point of instrument entry into the working area is an urgent task of surgery and scientific medicine. A structural synthesis of a parallel structure mechanism designed for robotic laparoscopic surgery has been performed. The proposed mechanism is equipped with arcuate guides with slots installed on the base perpendicular to each other. At the intersection of the slots, there is a bushing through which a straight shaft connected to the output link moves linearly. This arrangement provides a constant entry point, which allows the developed mechanism to be used in laparoscopic surgery and studies of plasma properties. For this mechanism, the inverse problem of positions has been solved, the working area has been determined, and a 3D model has been developed.

Investigation of the Possibilities of Using Soybean Oil as an Ecological Additive to Petroleum Diesel Fuel

One of the most important areas of internal combustion engine improvement is its adaptation to work on alternative fuels. Motor fuels obtained from renewable plant raw materials are considered to be promising alternative fuels. The article considers the possibility of using soybean oil as an ecological additive in petroleum diesel fuel. The features of soybean oil production and the physico-chemical properties of soybean oil and a mixture containing 80 % (by volume) of petroleum diesel fuel and 20 % of soybean oil are researched. Computational studies of the processes of fuel atomization and mixture formation in the D-245 diesel engine operating on mixtures of petroleum diesel fuel and seed oil have been performed. Experimental studies of the D-245 diesel engine operating on petroleum diesel fuel and the specified blended fuel have been carried out. Conversion of a diesel engine from petroleum fuel to mixed one leads to a decrease in integral emissions per test cycle: nitrogen oxides by 19.1 %, carbon monoxide — by 10.5 %, unburned hydrocarbons - by 8.9 %.

Multi-Criteria Design Optimization of Delta Robot with Four Degrees of Freedom

A delta robot with three degrees of freedom, having been well studied over the past 40 years, is one of the most popular parallel mechanisms. Nowadays, an urgent task is to study the properties of various modifications of this mechanism. The article considers a delta robot with four degrees of freedom, in which one of the kinematic chains with a parallelogram is divided into two, allowing the output link to have an additional rotational degree of freedom. To maximize the working area and minimize the cost of modification the optimization of the robot design was performed. The problem of maximizing a cubic workspace has been solved.

Advantages of Implementing Virtual Reality Tools in Design and Technological Preparation of Production

Along with digital modeling, the key modern technologies include virtual (VR) and augmented (AR) reality, the use of which is a prerequisite for the implementation of the fourth industrial revolution, also known as Industry 4.0. However, at Russian enterprises, these tools have not become widespread yet. The paper analyzes the possibility of using the tools of virtual and augmented reality and introduces the available Russian instruments. Practical examples consider the application in this area of — one of them — the VRConcept system — in detail. The availability of support in the VRConcept system for the data presentation format of the domestic computer-aided design system Compass-3D simplifies its implementation and use at the enterprise.

Coordination of Movements of Two-Handed 12-DOF Robot Manipulators at Their Joint Manipulation

The study focuses on a two-handed robot with twelve degrees of freedom, six for each arm, and gives an example of calculating generalized coordinates for the two-armed robot limbs at their joint manipulation. The initial data for obtaining generalized coordinates are represented by the location of the work object, which is a cube. When solving the problem, the last arm links reach the faces of the work object with a given orientation. To obtain generalized coordinates, we used a hierarchical approach, which is based on an algorithm for solving the inverse problem of kinematics, and developed a control flow chart. The values ??of generalized robot coordinates were obtained for each location of the object of work, taking into account the kinematic constraints in the joints of the robot actuator. Findings of research show that it is possible to obtain generalized coordinates for the coordinated movement of the robot actuators with tree-like kinematic scheme.

Selection of the Optimal Structural Design of a Spar Composite Wing

This paper describes a method for optimizing the design of a spar-type composite aircraft wing structure based on multi-criterion approach. Two types of composite wing structures such as two-spar and three-spar ones were considered. The optimal design of a wing frame was determined by the Pareto method basing on three criteria: minimal weight, minimal wing deflection, maximal safety factor and minimal weight. Positions of wing frame parts, i.e. spars and ribs, were considered as optimization parameters. As a result, an optimal design of a composite spar-type wing was proposed. All the calculations necessary to select the optimal structural and design of the spar composite wing were performed using nonlinear static finite element analysis in the FEMAP with NX Nastran software package.