Real Machine Research Articles

Real machine Test inversion research of J Pumped Storage Power Station

Accurate prediction of transition process is an important issue in the design and operation of pumped storage power station. In this paper, combined with load rejection test of J Pumped-storage Power Station, the basic equation of water flow motion and the element matrix equation of the turbine were established first, and the calculation model was established through HYSIM software. Then for the 100% load rejection control condition, the inversion calculation and analysis of actual load rejection test under the same boundary condition were carried out. According to the comparison process line between numerical simulation and measured data of the surge-chamber water level, a comprehensive combination calculation was used to calibrate the impedance coefficient of surge-chamber. Finally, based on the calibrated impedance coefficient, a new calculation model was established, and the inversion calculation was carried out again. By comparing the numerical simulation and measured data of volute and tail pipe pressure, the pressure pulsation characteristics of the characteristic parameters of the unit were obtained, and the correction value of pressure pulsation was obtained. The calibration method and pressure pulsation correction method adopted in this paper can provide a reference for the inversion analysis of load rejection test in similar power stations.

FMEA Application in the Design and Manufacture of Modern and Advanced Electrical Machines

In this paper, an original design failure mode and effects analysis methodology that can be applied to all modern and advanced electrical machines has been proposed. The developed methodology application is possible in the real electrical machines manufacture, which is confirmed by “Tekhnodinamika” holding representatives. On the example of the high-torque permanent magnets synchronous motor, the stages of the electrical machine hierarchical decomposition, the definition of the electrical machine and its components functions, the theory of failures and failure modes have been considered. The prospects and the opportunities that failure mode and effects analysis open in the design and in the production of modern and advanced electrical machines have been described. Proposed failure mode and effects analysis methodology application in electrical machines engineering will allow avoiding serious failures in commercially available electrical machines, as well as collecting into one system the rules that should be followed by electrical machines designers and manufacturers. The regulated failure mode and effects analysis methodology usage in the electrical machines design and manufacture should significantly improve the quality of manufactured products, increase its competitiveness and consumer qualities, and also reduce production costs.

Ukryte naruszenia bezpieczeństwa w układach automatycznego sterowania procesami technologicznymi

The progressing automation and robotization in the industrial plants as well as the increasing complexity of the control systems of integrated machines make it necessary to constantly improve the functional safety of machines through the correct validation of safety systems. Despite the validation process carried out, the potential software errors may reveal during the usage of the machine as hidden security breaches. The article presents examples of security breaches of real machine tools and attempts to implement solutions of automated mechanisms for detecting security problems. Another aspect of the article is the new approach for detecting hidden security breaches. Using the „digital twin” model of the machine, a program that generates a sequence of events for testing control systems, and the use of a virtual reality (visual verification of the safety programs), it is possible to maximize the functional safety functions of the machine.

THE USE OF DISCRETE WAVELET ANALYSIS OF VIBRO-ACOUSTIC SIGNALS TO DETECT THE POWER SUPPLY ASYMMETRY OF ROTATING ACCOMPANYING ELECTRIC MACHINES

The work shows that among the existing sufficiently described and studied approaches that are suitable for analyzing the temporal realization of a vibosignal, which can be obtained during the operation of a real electric machine, one can single out Fourier transforms and discrete wavelet transformations. An analysis of the descriptions of vibro-acoustic signals given in the literature, caused by the asymmetry of the power supply, shows that this defect leads to the appearance of oscillations that contain a harmonic component localized at the frequency of the supply voltage of the electrical network. This fact justifies the expediency of analyzing the frequency range, which includes the frequency of the supply voltage, and the selection of the mother wavelet, based on the features inherent in a single harmonic oscillation. A method for detecting a defect in the asymmetry of power supply to rotating electric machines of alternating current using a discrete wavelet transformation of a vibro-acoustic signal is proposed. The frequency band has been established, which is advisable to analyze in order to identify the indicated defect. It was found that the detection of a power asymmetry defect with the use of the wavelet transform of the temporal realization of the vibroacoustic signal is advisable to carry out using the Haar maternal wavelet function, which provides a combination of a high degree of affinity of the maternal wavelet with the form of vibration change due to the introduced asymmetry and relative the simplicity of such a transformation. It is shown that when detecting power asymmetry, it is advisable to analyze the behavior of the wavelet coefficients of the frequency band, which includes the frequency of the supply voltage of the electric machine. Since the influence of the indicated defect on other frequency bands will be minimal, the analysis of the behavior of their wavelet transform coefficients in order to identify the indicated defect is ineffective. A numerical criterion for assessing the influence of power asymmetry on the wavelet transform coefficients is proposed in the form of the mean square value of the wavelet coefficients of the informative frequency band in the study of the time interval, which significantly exceeds the period of the supply voltage of the electric machine. It is shown that this criterion has a reduced sensitivity to the impact of non-informative single disturbances that may arise during the operation of an electric machine. Keywords: electric machine, rotor unbalance, defect, burst, wavelet transform.

Carrier delay-based method for development of the tracks for the transitions between patterns on 3D braiding machines with continuous rotating horn gears

The pattern changes on the 3D rotary braiding machines (maypole principle with horn gears with full and empty slots) require complex planning of the carrier positions and timing and allow for production of bifurcated and other complex braids with variable cross sections for medical and technical applications. Another common application of pattern changes is to make a visually different pattern for marking of the remaining length of rope when used in a climbing context or for generally lengthened pieces for medical sutures. The development of such samples has previously been done using the trial-and-error method. This paper presents one rule for supporting a more systematic and purposeful trial, which significantly speeds up the development process. After a short review of the related literature, the main theoretical background is given and two practical cases for pattern change are demonstrated. The patterns were developed using numerical simulation before being tested on a real braiding machine. With this paper the authors hope to give some motivation for the remaining braiders in the world to continue working on the development of systematic rules for this complex process.

Efficiency and Sustainability Analysis of the Repair and Maintenance Operations of UNS M11917 Magnesium Alloy Parts of the Aeronautical Industry Made by Intermittent Facing

This paper analyzes the efficiency and sustainability of facing operations that are required within maintenance operations in the aeronautical industry. Due to the elevated cost and environmental impact of such processes, reducing the operating time while repairing parts is required. In this work, an experimental study of intermittent facing carried out on a magnesium alloy rod was developed. The experiment resembles real repair and maintenance machining operations, where an intermittent facing represents a more realistic scenario and where the results obtained in continuous turning studies are not always applicable. The work was performed with different cooling and lubrication systems and various cutting conditions, also considering the size of the interruption to analyze their impact in the surface roughness. To this end, surface finished in different measuring zones was studied. The aims of the study are to get a better understanding of the intermittent facing process in magnesium alloys typically employed in aeronautical applications and find the most efficient cutting parameters to obtain an improved surface under the safest and most environmentally respectful conditions.

Drive axis controller optimization of production machines based on dynamic models

The paper deals with the creation and implementation of a methodology for optimizing the parameters of cascade control of the machine tool axis drives. The first part presents the identification of a dynamic model of the axis based on experimental data from measuring the axis dynamics. The second part describes the controller model, selection of optimization objective functions, and optimization of constraint conditions. The optimization of controllers is tuned by simulation using identified state-space model. Subsequently, the optimization procedure is implemented on the identified model, and the found control parameters are used on a real machine tool linear axis with different loads. The implementation of the proposed complex procedure on a real horizontal machine tool proved the advantage of simultaneous tuning of all parameters using optimization methods. The strategy solves the problem of mutual interaction of all control law parameters disabling effective usability of gradual sequential tuning. The methodology was developed on a speed control loop, the tuning of which is usually the most difficult due to the close interaction with the dynamic properties of the machine mechanics. The whole procedure is also applicable to the position and current control loop.

VERICUT - CONFIGURING CNC SYSTEMS FOR TURNING CENTER WITH SUB-SPINDLE

This report discusses the configuration of some preparatory and auxiliary commands for the Fanuc 18i TB CNC system for a counter-spindle lathe using special macros called Vericut macros. In most cases, this is necessary because the Vericut library of machines and CNC systems does not have the specific machine and system or do not correspond to the actual ones, i. e. there is no match between them. The need to configure the CNC control system is related to the fact that it is possible to perform simulation, optimization and verification of control programs in a virtual environment before proceeding to the processing of workpieces on the real machine.

Chatter Stability Prediction and Process Parameters’ Optimization of Milling Considering Uncertain Tool Information

Stability is the prerequisite of a milling operation, and it seriously depends on machining parameters and machine tool dynamics. Considering that the tool information, including the tool clamping length, feeding direction, and spatial position, has significant effects on machine tool dynamics, this paper presents an efficient method to predict the tool information dependent-milling stability. A generalized regression neural network (GRNN) is established to predict the limiting axial cutting depth, where the machining parameters and tool information are taken as input variables. Moreover, an optimization model is proposed based on the machining parameters and tool information to maximize the material removal rate (MRR), where the GRNN model is taken as the stability constraint. A particle swarm optimization (PSO) algorithm is introduced to solve the optimization model and provide an optimal configuration of the machining parameters and tool information. A case study has been developed to train a GRNN model and establish an optimization model of a real machine tool. Then, effects of the tool information on milling stability were discussed, and an origin-symmetric phenomenon was observed as the feeding direction varied. The accuracy of the solved optimal process parameters corresponding to the maximum MRR was validated through a milling test.

Analytical modelling of edge chipping in scratch of soda-lime glass considering strain-rate hardening effect

Soda-Lime Glass (SLG) has been widely used in the creation of highly-functionalised optical devices. However, machining of SLG easily resulted in various defects. Among these defects, edge chipping (EC) can be treated as the most damageable in terms of both mechanical properties and optical performances. Although efforts have been paid to this topic, previous investigations (i) focused on edge chipping in low strain rate, which was 101-102 times lower than the ones in real machining, (ii) assumed edge chipping shape as circular, while the experiments in this work proved this assumption might be inaccurate in high strain rate circumstances, and (iii) were experimental efforts, resulting in limited knowledge of process principles. To fill this gap, this paper aims to propose an analytical model to calculate the size and the shape of edge chipping in scratch of soda-lime glass with the special consideration of strain-rate hardening effect. A series of experimental trials were performed to validate the model accuracy under different parameters. The details in scratching process were discussed by force analysis. A typical model application was given as well, which was designing the machining strategy based on the proposed model so that a required region with limited edge chipping can be obtained. Considering the research gaps mentioned above, the key findings in this paper are expected to be meaningful and helpful to provide references in the real fabrication of high-valued optical devices made of SLG.

Study of temperature and stresses using finite element analysis in turning of C45 material

Parts machined by high cutting speeds can often exhibit high fatigue strength, increased micro-hardness in the surface layers and plastic deformations, due to the tool cutting edge radius associated with the induced stresses. The changing of rake and clearance angles has an important influence on the chip formation, cutting forces, residual stresses, temperatures in both the workpiece and the tool. International research on the influence of geometric parameters of the tool on the entire cutting process, are of particular importance to understand this process development. The approach of this study, considers the parametric realization of the cutting tool profile - a coated TiC turning chisel, which will be used in the finite element simulation of the orthogonal turning process. Deform 2D application, which is a powerful simulation engine was chosen and allows the correct simulation of the cutting process in real machining conditions. Deform 2D enables the automatically meshing and remeshing generation and also the optimization whenever needed and wherever is required a high accuracy, thereby reducing the overall difficulty of the problem and the computational requirements. Using Lagrangian discretization, the machining process was simulated and made possible to observe and present a series of conclusions and own points of view regarding the temperature distribution at the tool tip and in the workpiece, the effective stresses distribution and the cutting force variation under the rake and clearance angles influences.

Multi-Objective Optimization of Process Parameters to Enhance Efficiency in the Shoe-Type Centerless Grinding Operation for Internal Raceway of Ball Bearings

In this article, new research on the multi-objective optimization of the process parameters applied to enhance the efficiency in the shoe-type centerless grinding operation for the inner ring raceway of the ball bearing made from SUJ2 alloy steel is presented. The four important input parameters for this process, which included the normal feed rate of fine grinding (Snf), the speed of the workpiece (Vw), the cutting depth of fine grinding (af), and the number of ground parts (Np), were investigated. The aim of the study was to find the most appropriate value set of process parameters in order to, simultaneously minimize the grindstone wear (Gw), maximize the material removal rate (MRR) and the total number of ground parts in a grinding cycle (N’p), while guaranteeing other technology requirements such as surface roughness Ra ≤ 0.5 (µm), oval level Op ≤ 3 (µm), etc. In order to solve the problem, based on the experimental data, in which the grindstone wear was measured online by a measuring system consisting of two pneumatic probes, the optimization of the target functions of Gw, N’p, and MRR and mathematical models that express the dependencies of outcome parameters Gw, Ra, Op, MRR, etc. on the process parameters were determined. Therefore, a global optimal solution of such a discrete and nonlinear multi-objective optimization problem was solved by using a genetic algorithm, presenting the most appropriate process parameters as follows: Snf = 15.38 (µm/s), Vw = 6.00 (m/min), af = 11.76 (µm), and Np = 20 (parts/cycle). In addition, the impact of the four process parameters (Snf, Vw, af, Np) on the wear of the grinding wheel (Gw), the oval level of parts (Op), and the surface roughness of parts (Ra) was evaluated. The discovered technology mode has been applied to the real machining process for the inner ring raceway of the 6208_ball bearing made from SUJ2 alloy steel, and the outcome showed a much better result in comparison with default setting modes, while still ensuring the technology requirements. The difference between the predicted values and the real values of the parameters Gw, Ra, Op, and MRR were controlled within 5% of the ranges.

Construction method of shop-floor digital twin based on MBSE

Digital twin (DT) technology is essential for achieving the fusion of virtual-real cyber-physical systems. Academics and companies have made great strides in the theoretical research and case studies of constructing the shop-floor digital twin (SDT), which is the premise of applying DT technology on the shop floor. A shop floor is a large complex system that involves many elements including people, machines, materials, methods, and the environment and processes, such as the technical flow, business process, logistics, and control flow. However, most of the developed cases lack a hierarchical, structured and modularized implementation framework for the development of an SDT system, which leads to problems such as a low reuse rate of the system blocks, lack of scalability, and high upgrade and maintenance costs. In response to these issues, we propose a construction method of the DT for the shop floor based on model-based systems engineering from the perspective of the system. In this method, a comprehensive DT model for the shop floor is gradually constructed by using system modeling language, the modeling method “MagicGrid,” and the “V model” of systems engineering. The model includes four dimensions of the shop-floor requirements, structure, behavior, and parameters, as well as three stages (the problem domain, solution domain, and implementation domain), and connects nine steps of the “V model,” including the system requirements, system architecture, subsystem implementation, subsystem integration, and system verification. Then, based on an example of a real NC machining shop floor, subsystems including a visualization system, synchronization system, and simulation system, are discussed. Finally, the functions of the integrated systems are verified based on the requirements, including the real-time synchronization of “man, machine, material, and method” and the transient simulation in real time. The numerical indicators of the integrated system are verified, including the model completeness and synchronization timeliness.

Inversion calculation and prediction of extreme conditions by in-situ test of real machine in a hydropower station

The in-situ test of the real engine in hydropower station is a necessary test before the unit is put into operation. During the test, the problems in the test process can be found through the auxiliary inversion calculation, and the calculation and analysis of extreme conditions can provide important support for the unit’s permanent operation. First of all, this paper analyzes the problem that the maximum pressure of the spiral shell and the increase rate of the unit speed in the load rejection test of the hydropower station exceed the control standard. Through inversion calculation, it is found that the closing law of the guide vane of the unit is different from the set closing law, and the robustness of the closing law is poor; then, combined with the test situation, the closing law of the guide vane of the unit was optimized. While the adjusted load rejection test was simulated under the same boundary conditions, and the measured data and numerical calculation results were compared and analyzed to obtain the modified values of the characteristic parameters. Finally, the extreme conditions in the transition process of large fluctuations are predicted and calculated by numerical simulation. This research idea provides reference and guidance experience for similar projects.

Navigation system for heading machines in potash mines

Mining operations at potash mines are carried out by heading machines. Setting of a direction and control of the movement of the machines is carried out by the mine surveyor and by the machine operator in the manual mode. The lack of automation of this process during production leads to large labor costs of the mine surveying service, while the experience of the machine operator affects accuracy of maintenance of a specified course. Currently, there are no ready-made technical products for automating the process of setting the course and controlling the movement of heading machines. This paper deals with the implementation of the navigation system for heading machines in the underground mines of Uralkali company. At the mines of Uralkali, the requirements for the accuracy of such a system are dictated by the requirements for the accuracy of mine surveying support for underground mining operations in driving new roadways. Possible ways of constructing navigation systems and the problems of their application are considered. The analysis of the existing methods shows that the most promising option for navigation of heading machines in underground mine openings are the systems based on the principles of inertial navigation. To use such systems in underground mines and to ensure the required accuracy, the technical requirements for the systems are formulated. It is shown that modern strapdown inertial navigation systems satisfy the required accuracy. On their basis, a prototype of the heading machine navigation system was developed, and its ground tests were carried out. The achieved accuracy of the system makes it possible to proceed to testing of a real heading machine in a mine. The study was supported by the Russian Science Foundation, Project No. 19-77-30008.

Air-Cored Resonant Induction Machines: Comparison of Capacitor Tuning Criteria and Experimental Validation

The operation of air-cored resonant induction machines is very sensitive to the tuning of the capacitors. By using the equivalent circuit equations, this article explores in detail the machine performances under four different tuning criteria: (a) both stator and rotor capacitors resonating with the stator and rotor self-inductances; (b) both capacitors resonating with the leakage inductances; (c) stator capacitors tuned to compensate for the overall stator terminal reactance and no rotor capacitors; (d) stator capacitors only to cancel out the machine ideal input reactance neglecting resistances, which is the new option introduced in this article. Extensive comparisons of all tuning options in torque, efficiency, power factor, capacitor size, and feasibility are presented and their performances are compared with a pure air-cored induction machine without capacitors. Analytic expressions for the maximum efficiency and maximum torque and related slip values are also derived as functions of the machine parameters, which provides a valuable tool for design optimization. A numerical case study based on parameters of a real air-cored induction machine is discussed and the article includes the first experimental validation to be carried out on a spinning air-cored resonant induction machine prototype. Results show that using only stator capacitors to compensate for the machine equivalent terminal reactance can be a practical choice to achieve both high torque and high efficiency and avoid rotor capacitors.

KIcker: An Industrial Drive and Control Foosball System automated with Deep Reinforcement Learning

The majority of efforts in the field of sim-to-real Deep Reinforcement Learning focus on robot manipulators, which is justified by their importance for modern production plants. However, there are only a few studies for a more extensive use in manufacturing processes. In this paper, we contribute to this by automating a complex manufacturing-like process using simulation-based Deep Reinforcement Learning. The setup and workflow presented here are designed to mimic the characteristics of real manufacturing processes and proves that Deep Reinforcement Learning can be applied to physical systems built from industrial drive and control components by transferring policies learned in simulation to the real machine. Aided by domain randomization, training in a virtual environment is crucial due to the benefit of accelerated training speed and the desire for safe Reinforcement Learning. Our key contribution is to demonstrate the applicability of simulation-based Deep Reinforcement Learning in industrial automation technology. We introduce an industrial drive and control system, based on the classic pub game Foosball, from both an engineering and a simulation perspective, describing the strategies applied to increase transfer robustness. Our approach allowed us to train a self-learning agent to independently learn successful control policies for demanding Foosball tasks based on sparse reward signals. The promising results prove that state-of-the-art Deep Reinforcement Learning algorithms are able to produce models trained in simulation, which can successfully control industrial use cases without using the actual system for training beforehand.

Learning based compilation of embedded applications targeting minimal energy consumption

Abstract The choice of correct optimization passes during compilation is one of the major factors that determines the performance and energy consumption of an application when executed on a target hardware. However, making such a choice is challenging since it requires knowledge of target architecture, code features and compiler pass interdependence. Software developers mostly rely on heuristic approaches while choosing the optimization passes. However, such heuristic solutions and random choices often yield sub-optimal results. In this work, we propose an automated technique of determining the optimal compiler optimization setting for minimum energy consumption utilizing power profile results and performance characteristics from real hardware and machine learning models. The proposed approach on one hand brings about reduction in energy consumption and on the other releases embedded software developers from making the complicated compiler optimization choices for each application. Our proposed five phase strategy when implemented on multi-core ARM based ODROID-XU4 experimental platform using the Clang Compiler shows a maximum of 8.43% improvement in power dissipation and a maximum of 27.27% in energy consumption for MiBench and Polybench representative benchmarks in comparison to state-of-art energy aware compilation strategies.

Aerodynamic and Structural Strategies for the Rotor Design of a Wind Turbine Scaled Model

Experimental tests performed in a wind tunnel or in a natural laboratory represent a fundamental research tool to develop floating wind technologies. In order to obtain reliable results, the wind turbine scale model rotor must be designed so to obtain a fluid-structure interaction comparable to the one experienced by a real machine. This implies an aerodynamic design of the 3D blade geometry but, also, a structural project to match the main aeroelastic issues. For natural laboratory models, due to not controlled test conditions, the wind turbine rotor model must be checked also for extreme winds. The present paper will focus on all the strategies adopted to scale a wind turbine blade presenting two studied cases: the first is a 1:75 scale model for wind tunnel applications and the second a 1:15 model for natural laboratory tests.

The design of the C mobile earth station simulator based on C language

The communication equipment software of the Global Maritime Distress and Safety System is based on DOS platform, and the equipment operation simulator used for training and assessment is generally developed by VC, VB and FLASH technology. There are a lot of difference between the simulator and the real machine on the interface and the operating response. The operation of the simulator is done with mouse, while the operation of the real machine must be done with the keyboard only on board ships. The Inmarsat-C mobile earth station simulator has being developed by C language. The simulator terminal operating interface and response is identical with the real machine operation because the developing language of the simulator is the same as the real machine. Because the adoption of the doubly-linked list data structure, program structure is clear and code is simplified.