The method for identifying of inaccuracy causes in turning machining center by processing a sample part

The article discusses the issues of the processing method of a turning machining center for processing the accuracy of processing a sample part. The model of sample part with the smallest possible control surfaces processed by various shaping methods has been developed to detect the amount of machine errors, such as the accumulated error of the screw pitch, or the axial non-perpendicularity, or the misalignment of the X and Y drives. This allows you to get more complete information of the equipment accuracy. A test procedure is presented according to the results of measuring each surface of the sample part

Measurement of total normal length of helical cylindrical gears by three-axis indicator on five-axis CNC machine

The article discusses a method for automated measurement of the length of the general normal of a helical cylindrical wheel, which allows to obtain its exact value without removing the part after gear processing with disk or end mills. The measurements are carried out by means of an automated supply of a three-coordinate linear measurement indicator to the calculated measurement points. The formulas for calculating the length of the general normal are given, which allow calculating the value of the length of the general normal and the correction value of the CNC gear ring processing program for two and one-point measurement schemes with the indicator. The use of the two-point method of measuring the length of the general normal with a three-coordinate indicator made it possible to measure the length of the general normal without removing the processed gear wheel from the mandrel, the single-point method completely eliminates the possibility of adjustment defects and reduces the complexity of carrying out machine changeovers in the mode of single and small-scale processing of gears. Comparison of gear measurement data with the three-coordinate indicator Mahr and a specialized CNC gear measuring machine give similar values and confirm the possibility of using the developed scheme to measure the length of the common normal

Adaptive calibration of the angle sensor for gyroscope

The article proposes methods of control and testing of information-measuring systems. The methods for calibrating the angle sensor included in the flight control system are considered. The principle of creating a test bench for evaluating the accuracy of angle sensor calibration is defined. The process of neural network training is described, which allows to compensate the disadvantages inherent to the traditional calibration method. A comparative analysis of the traditional method of joint calibration of angle sensors with the method based on the use of neural networks is performed

Power supply reliability models of oil production facilities

This paper presents power supply systems reliability models of oil production facilities. There are two types of electrical complexes: an electrical network with a consumer sensitive to voltage dips and an electrical network with a consumer with technological redundancy. A comprehensive analysis of the power supply system and the power consumer allowed us to clarify the reliability indicators and determine the direction of improving the power supply reliability to oil and associated petroleum gas production facilities

Improving the quality of design calculations of viscous flow in low-flow centrifugal compressor stages by methods of computational fluid dynamics through reasonable application of different turbulence models

The paper considers the issue of improving the quality of the numerical experiment in the calculation of viscous gas in the flowing part of a low-flow centrifugal compressor stage. The choice of turbulence model in creating a calculation model for calculations by methods of computational fluid dynamics is substantiated. As object of research is chosen low-flow stage with conditional flow coefficient Ф=0,008 and relative width at impeller outlet b2 /D2 =0,0133. The issue of qualitative modeling of friction losses in low-flow stages is of fundamental importance and is directly related to the choice of turbulence model. It is shown that the choice of low-Reynolds turbulence models in the case of unloaded and discontinuous low-flow stages can be made from the main common models (SpalartAllmaras, SST, k-ω) based on the economy of calculations, speed of convergence, solution stability and adequacy of the obtained results. For models with wall functions, the quality of the mesh model and the observance of the dimensionless distance to the wall y+ throughout the calculation domain are particularly important. For highReynolds turbulence models, at values of y+=25...50 on all friction surfaces of the computational domain in the optimal mode of operation, the grid independence of the solution for the entire gas-dynamic characteristic is ensured. It is unacceptable for y+ to fall into the transition region of 4...15 between the viscous sublayer and the region of the logarithmic velocity profile

Methods of synchronization of electric drives not mechanically connected

The article provides a comparative analysis of the structures of synchronization of the motion of electric drives of medium and high power. A comparison of synchronization structures is made in terms of the impact on the final operation of the system and hardware synchronization methods in terms of applicability and maximum performance. The mathematical apparatus is based on the principle of separation of the movements of each of the electric drives and the representation of its transfer function in matrix form. The control ranges and speed of different types of systems are compared experimentally by evaluating the speed of data transmission and evaluating the speed ripple at low revs.

Using correlation matrices in predicting airline performance

The article considers the issue of making forecasts of the main indicators of the activities of airlines for their effective functioning in the air transportation market. It describes the life cycle of airlines and provides a classification of the forecasts that are currently being made. The interrelation of correlations of the key parameters of the airline’s functioning is considered, the use of correlations in forecasting is shown, actual calculations are presented, and a significant increase in forecast accuracy when using this forecasting method is demonstrated.

Methodology for selecting installation sites for automatic power redundancy systems of DC traction substations

The paper presents a method for selecting the installation locations of power reservation systems of traction substations to reduce electricity losses in the system of traction power supply of DC railways. The analysis of the main criteria affecting the efficiency and reliability of the DC traction power supply system is carried out. The algorithm for selecting the installation locations of power reservation systems has been developed, which allows selecting traction substations that provide the greatest energy effect during the installation of systems

Changes in structural-phase state and physicochemical properties of tungsten-free TIC-TiNi hard alloys after various types of ion-beam treatment

Using experimental methods of analysis, the morphology, elemental composition and chemical state of hard alloys of the «TiC-TiNi» system in the initial state and after various types of ion-beam treatment have been investigated. It is found that the effect of a continuous ion beam leads to an increase in the microhardness of the investigated alloys by 10–12 %. When samples are irradiated with a pulsed ion beam, as a result of destruction of surface layers, the microhardness value decreases by 20 %, as a result of which this type of modification is not preferable for alloys of the TiC-TiNi system

Investigation of performance properties of rubber with metal fillers

The work conducts laboratory tests on the rubber of the first group of GOST 8752-70 with the introduction of the metal components. The filler is introduced into the rubber mixture on laboratory rollers. Fine powders of copper (Cu), tin (Sn) and lead (Pb) are used as fillers. The dependences of the temperature in the contact zone of the sample and the body of revolution on the concentration of the filler and the dependence of wear on the concentration of the filler for the same loads and sliding speeds are obtained, the fillers that give the rubber the greatest wear resistance are revealed, and the rational amount of the filler is determined. The positive results of laboratory tests give grounds to recommend various equipment including aerospace equipment for use in sealing devices of hydraulic systems, rubber products with metal fillers in the indicated concentrations, which will extend their service life and increase their reliability