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Machines
Volume 8
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Machines, Volume 8, Issue 1 (March 2020) – 15 articles

Cover Story (view full-size image): The performance of measurement or manufacturing systems in high-precision applications is dependent upon the dynamics of the system, as vibration can be a significant contributor to measurement uncertainty and process variability. Despite the importance of mechanical performance, current measurement systems implement little or no active condition monitoring, and so it is difficult to verify the performance of the system and monitor structural deterioration over time. While technologies are available that use accelerometers and laser vibrometers to rapidly measure and process structural dynamic data, the software infrastructure is yet to be available in an open source or standardised format to allow inter-platform use. As such, it is vital that new vibration condition monitoring systems be developed which enable the live performance appraisal of a measurement or manufacturing system. View this paper
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22 pages, 2573 KiB  
Article
Electric Machine Design Tool for Permanent Magnet Synchronous Machines and Induction Machines
by Svenja Kalt, Jonathan Erhard and Markus Lienkamp
Machines 2020, 8(1), 15; https://doi.org/10.3390/machines8010015 - 24 Mar 2020
Cited by 19 | Viewed by 9057
Abstract
The rising mobility demand of today’s society leads to an increasing strain of noise and pollutant emissions on people and the environment. An increasing environmental awareness and the scarcity of fossil fuels are increasingly placing alternative-powered vehicles in the focus of politics, research [...] Read more.
The rising mobility demand of today’s society leads to an increasing strain of noise and pollutant emissions on people and the environment. An increasing environmental awareness and the scarcity of fossil fuels are increasingly placing alternative-powered vehicles in the focus of politics, research and development. Electric vehicles represent a promising solution to this problem. The electric machine represents a design control lever for the optimization of the electric powertrain with regard to efficiency, power, weight and size. Therefore, accurate and realistic machine design tools for the design of electric machines are becoming increasingly important. In this paper, the authors present an electric machine design tool for electric machines using MATLAB® in order to enable an automated machine design. The electric machine design tool is published under an LGPL open source license. Full article
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20 pages, 2198 KiB  
Article
Sensorless Control of Permanent Magnet Synchronous Machine with Magnetic Saliency Tracking Based on Voltage Signal Injection
by Vasilios C. Ilioudis
Machines 2020, 8(1), 14; https://doi.org/10.3390/machines8010014 - 19 Mar 2020
Cited by 9 | Viewed by 4086
Abstract
This paper presents a sensorless control method of a permanent magnet synchronous machine (PMSM) with magnetic saliency estimation. This is based on a high-frequency injection (HFI) technique applied on the modified PMSM model in the γδ reference frame. Except for sensorless control, an [...] Read more.
This paper presents a sensorless control method of a permanent magnet synchronous machine (PMSM) with magnetic saliency estimation. This is based on a high-frequency injection (HFI) technique applied on the modified PMSM model in the γδ reference frame. Except for sensorless control, an emphasis is placed on the magnetic saliency estimation to indicate a practical approach in tracking PMSM inductance variations. The magnetic saliency is determined using calculations embedded in the speed and position algorithm through current measurements. A notable characteristic of the modified PMSM model is that the corresponding rotor flux integrates both permanent magnet and saliency term fluxes. In applying a HFI technique for sensorless control, the structure of the PMSM flux model is formatted accordingly. A novel inductance matrix is derived that is completely compatible with the HFI methodology, since its elements include terms of angle error differential and average inductances. In addition, a sliding mode observer (SMO) is designed to estimate the speed and angle of rotor flux based on equivalent control applying a smooth function of the angle error instead of a sign one to reduce the chattering phenomenon. The control strategy is principally based on the adequacy of the proposed modified model and on the appropriateness of the SMO structure to successfully track the rotor flux position with the required stability and accuracy. Simulation results demonstrate the performance of the PMSM sensorless control verifying the effectiveness of the proposed algorithm to detect PMSM saliency, speed and position in steady state and transient modes successfully. Full article
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2 pages, 162 KiB  
Editorial
Advances in CAD/CAM/CAE Technologies
by Panagiotis Kyratsis, Konstantinos Kakoulis and Angelos P. Markopoulos
Machines 2020, 8(1), 13; https://doi.org/10.3390/machines8010013 - 13 Mar 2020
Cited by 16 | Viewed by 6271
Abstract
Computer-aided design, computer-aided manufacturing and computer-aided engineering (CAD/CAM/CAE) technologies find more and more applications in today’s industry, e [...] Full article
13 pages, 2653 KiB  
Article
Experimental Study on the Influence of Machining Conditions on the Quality of Electrical Discharge Machined Surfaces of aluminum alloy Al5052
by Angelos P. Markopoulos, Emmanouil-Lazaros Papazoglou and Panagiotis Karmiris-Obratański
Machines 2020, 8(1), 12; https://doi.org/10.3390/machines8010012 - 02 Mar 2020
Cited by 22 | Viewed by 3184
Abstract
Although electrical discharge machining (EDM) is one of the first established non-conventional machining processes, it still finds many applications in the modern industry, due to its capability of machining any electrical conductive material in complex geometries with high dimensional accuracy. The current study [...] Read more.
Although electrical discharge machining (EDM) is one of the first established non-conventional machining processes, it still finds many applications in the modern industry, due to its capability of machining any electrical conductive material in complex geometries with high dimensional accuracy. The current study presents an experimental investigation of ED machining aluminum alloy Al5052. A full-scale experimental work was carried out, with the pulse current and pulse-on time being the varying machining parameters. The polishing and etching of the perpendicular plane of the machined surfaces was followed by observations and measurements in optical microscope. The material removal rate (MRR), the surface roughness (SR), the average white layer thickness (AWLT), and the heat affected zone (HAZ) micro-hardness were calculated. Through znalysis of variance (ANOVA), conclusions were drawn about the influence of machining conditions on the EDM performances. Finally, semi empirical correlations of MRR and AWLT with the machining parameters were calculated and proposed. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining)
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17 pages, 5176 KiB  
Article
Optimal In-Operation Redesign of Mechanical Systems Considering Vibrations—A New Methodology Based on Frequency-Band Constraint Formulation and Efficient Sensitivity Analysis
by Erich Wehrle, Veit Gufler and Renato Vidoni
Machines 2020, 8(1), 11; https://doi.org/10.3390/machines8010011 - 28 Feb 2020
Cited by 5 | Viewed by 2267
Abstract
The vibrational behavior of components in mechanical systems like drives and robots can become critical under changes in the system properties or loading in operation. Such undesired vibration can lead to detrimental conditions including excess wear, fatigue, discomfort, and acoustic emissions. Systems are [...] Read more.
The vibrational behavior of components in mechanical systems like drives and robots can become critical under changes in the system properties or loading in operation. Such undesired vibration can lead to detrimental conditions including excess wear, fatigue, discomfort, and acoustic emissions. Systems are designed to avoid certain frequencies to avoid such problems, but system parameters can change during operation due damage, wear, or change in loading. An example is the change in system properties or operation state that then activates resonance frequencies in our system. Therefore, this work has the goal of modifying the modal behavior of a system to avoid vibrational problems. Methods of design optimization are applied to find a new optimum design for this altered condition. Here, this is limited to the addition of mass in order to move the resonance frequency out of critical ranges. This though requires a new formulation of the optimization problem. We propose a new constraint formulation to avoid frequency ranges. To increase efficiency, a reduced analytical sensitivity analysis is introduced. This methodology is demonstrated on two test cases: a two-mass oscillator followed by a test case of higher complexity which is a gear housing considering over 15,000 design variables. The results show that the optimization solution gives the position and amount of mass added, which is a discrete solution that is practically implementable. Full article
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14 pages, 2489 KiB  
Article
Enhancing Energy Efficiency of a 4-DOF Parallel Robot Through Task-Related Analysis
by Lorenzo Scalera, Paolo Boscariol, Giovanni Carabin, Renato Vidoni and Alessandro Gasparetto
Machines 2020, 8(1), 10; https://doi.org/10.3390/machines8010010 - 25 Feb 2020
Cited by 28 | Viewed by 4146
Abstract
Enhancing energy efficiency is one of the main challenges of today’s industrial robotics and manufacturing technology. In this paper a task-related analysis of the energetic performance of a 4-DOF industrial parallel robot is presented, and the optimal location of a predefined task with [...] Read more.
Enhancing energy efficiency is one of the main challenges of today’s industrial robotics and manufacturing technology. In this paper a task-related analysis of the energetic performance of a 4-DOF industrial parallel robot is presented, and the optimal location of a predefined task with respect to the robot workspace is investigated. An optimal position of the task relative to the robot can indeed reduce the actuators’ effort and the energy consumption required to complete the considered operation. The dynamic and electro-mechanical models of the manipulators are developed and implemented to estimate the energy consumption of a parametrized motion with trapezoidal speed profile, i.e., a pick-and-place operation. Numerical results provide energy consumption maps that can be adopted to place the starting and ending points of the task in the more energy-efficient location within the robot workspace. Full article
(This article belongs to the Special Issue Selected Papers from Advances of Japanese Machine Design)
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17 pages, 6740 KiB  
Article
Dependency of Machine Efficiency on the Thermal Behavior of Induction Machines
by Svenja Kalt, Karl Ludwig Stolle, Philipp Neuhaus, Thomas Herrmann, Alexander Koch and Markus Lienkamp
Machines 2020, 8(1), 9; https://doi.org/10.3390/machines8010009 - 24 Feb 2020
Cited by 6 | Viewed by 3190
Abstract
The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is [...] Read more.
The consideration of the thermal behavior of electric machines is becoming increasingly important in the machine design for electric vehicles due to the adaptation to more dynamic operating points compared to stationary applications. Whereas, the dependency of machine efficiency on thermal behavior is caused due to the impact of temperature on the resulting loss types. This leads to a shift of efficiency areas in the efficiency diagram of electric machines and has a significant impact on the maximum load capability and an impact on the cycle efficiency during operation, resulting in a reduction in the overall range of the electric vehicle. Therefore, this article aims at analyzing the thermal load limits of induction machines in regard to actual operation using measured driving data of battery electric vehicles. For this, a thermal model is implemented using MATLAB® and investigations to the sensitivity of model parameters as well as analysis of the continuous load capacity, thermal load and efficiency in driving cycles under changing boundary conditions are conducted. Full article
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27 pages, 2331 KiB  
Article
A Multi-Criteria Decision Framework Considering Different Levels of Decision-Maker Involvement to Reconfigure Manufacturing Systems
by Mohammed M. Mabkhot, Saber Darmoul, Ali M. Al-Samhan and Ahmed Badwelan
Machines 2020, 8(1), 8; https://doi.org/10.3390/machines8010008 - 21 Feb 2020
Cited by 6 | Viewed by 2209
Abstract
Reconfigurable Manufacturing Systems (RMSs) rely on a set of technologies to quickly adapt the manufacturing system capacity and/or functionality to meet unexpected disturbances, such as fluctuation/uncertainty of demand and/or unavailability/unreliability of resources. At the operational stage, such disturbances raise new production requirements and [...] Read more.
Reconfigurable Manufacturing Systems (RMSs) rely on a set of technologies to quickly adapt the manufacturing system capacity and/or functionality to meet unexpected disturbances, such as fluctuation/uncertainty of demand and/or unavailability/unreliability of resources. At the operational stage, such disturbances raise new production requirements and risks, which call upon Decision-Makers (DMs) to analyze the opportunity to move from a running configuration to another more competitive one. Such a decision is generally based on an evaluation of a multitude of criteria, and several multi-criteria decision-making (MCDM) approaches have been suggested to help DMs with the reconfiguration process. Most existing MCDM approaches require some assignment of weights to the criteria, which is not a trivial task. Unfortunately, existing studies on MCDM for an RMS have not provided guidelines to weigh the evaluation criteria. This article fills in this gap by offering a framework to set up such weights. We provide a comprehensive set of quantitative indicators to evaluate the reconfiguration decisions during the operation of the RMS. We suggest three weighting methods that are convenient to different levels of DM expertise and desired degree of involvement in the reconfiguration process. These weighting methods are based on (1) intuitive weighting, (2) revised Simos procedural weighting combined with the Technique for Order of Preferences by Similarity to Ideal Solution (TOPSIS), and (3) DM independent weighting using ELECTRE IV. The implementation of the suggested framework and a comparison of the suggested methods carried out on an industrial case study are described herein. Full article
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15 pages, 5487 KiB  
Article
Design of a Large Deployable Reflector Opening System
by Alessandro Cammarata, Rosario Sinatra, Alessio Rigano, Mattia Lombardo and Pietro Davide Maddio
Machines 2020, 8(1), 7; https://doi.org/10.3390/machines8010007 - 14 Feb 2020
Cited by 8 | Viewed by 3094
Abstract
Large Deployable Reflectors (LDR) are receiving considerable attention from aerospace government companies and researchers. In this paper, the design of the opening system of a LDR is presented. Starting from an elementary cell, a first ideal kinematic model is discussed. Then, a more [...] Read more.
Large Deployable Reflectors (LDR) are receiving considerable attention from aerospace government companies and researchers. In this paper, the design of the opening system of a LDR is presented. Starting from an elementary cell, a first ideal kinematic model is discussed. Then, a more complex “design model” including feasible design solutions for joints and links is developed. The final design avoids collisions between links while maintaining the original kinematic features. Full article
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11 pages, 3995 KiB  
Article
New Spectral Markers for Broken Bars Diagnostics in Induction Motors
by Georgii D. Baranov, Erivelton G. Nepomuceno, Michail A. Vaganov, Valerii Y. Ostrovskii and Denis N. Butusov
Machines 2020, 8(1), 6; https://doi.org/10.3390/machines8010006 - 28 Jan 2020
Cited by 9 | Viewed by 2402
Abstract
The paper discusses the spectral markers of fault rotor bars in induction motor current signature analysis (MCSA). The results of the simulation of the deterioration process for a single rotor bar, as well as the results of research for various mutual bracing of [...] Read more.
The paper discusses the spectral markers of fault rotor bars in induction motor current signature analysis (MCSA). The results of the simulation of the deterioration process for a single rotor bar, as well as the results of research for various mutual bracing of two broken bars, are reported. We proposed a simple empiric technique allowing one to obtain frequencies for spectrum markers of damaged rotor bars based on simulation analysis. The set of frequencies obtained in the experimental part of the study was compared with simulation results and the results of real-life measurements. The theoretical results were verified through the experiment with the real induction motor under load. Analysis of experimental results proved that the given algorithm for spectrum analysis is suitable for early detection of fault rotor bars in induction motors. Full article
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11 pages, 2846 KiB  
Article
Linkage and Cam Design with MechDev Based on Non-Uniform Rational B-Splines
by Mario Müller, Mathias Hüsing, Agnes Beckermann and Burkhard Corves
Machines 2020, 8(1), 5; https://doi.org/10.3390/machines8010005 - 21 Jan 2020
Cited by 6 | Viewed by 6018
Abstract
Several software products exist in order to support engineers during the mechanism design process. The software “Mechanism Developer” (abbr. MechDev) is one of these products. MechDev provides many functionalities concerning the kinematic and kinetostatic analysis of mechanisms based on revolute, prismatic as well [...] Read more.
Several software products exist in order to support engineers during the mechanism design process. The software “Mechanism Developer” (abbr. MechDev) is one of these products. MechDev provides many functionalities concerning the kinematic and kinetostatic analysis of mechanisms based on revolute, prismatic as well as cam joints. This paper will introduce the software MechDev and will outline these functionalities. Furthermore, it will name the advantages of MechDev compared to other software products. In order to give an impression of the functionality of the software, this paper also includes a special use case. This use case describes a cam mechanism with a prismatic roller-follower. In order to optimize the transmission angle of the cam mechanism, the cam is actuated by a servo drive. To mathematically model the angular input of the servo drive, Non-Uniform Rational B-Splines (NURBS) are described and applied. Thus, a nearly arbitrary input function can be described by few parameters. Full article
(This article belongs to the Special Issue Selected Papers from Advances of Japanese Machine Design)
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3 pages, 287 KiB  
Editorial
Acknowledgement to Reviewers of Machines in 2019
by Machines Editorial Office
Machines 2020, 8(1), 4; https://doi.org/10.3390/machines8010004 - 19 Jan 2020
Viewed by 1444
Abstract
The editorial team greatly appreciates the reviewers who have dedicated their considerable time and expertise to the journal’s rigorous editorial process over the past 12 months, regardless of whether the papers are finally published or not [...] Full article
17 pages, 7372 KiB  
Article
Performance Verification of a Flexible Vibration Monitoring System
by Patrick Bointon, Luke Todhunter, Adam Clare and Richard Leach
Machines 2020, 8(1), 3; https://doi.org/10.3390/machines8010003 - 03 Jan 2020
Cited by 3 | Viewed by 4103
Abstract
The performance of measurement or manufacturing systems in high-precision applications is dependent upon the dynamics of the system, as vibration can be a significant contributor to the measurement uncertainty and process variability. Technologies making use of accelerometers and laser vibrometers are available to [...] Read more.
The performance of measurement or manufacturing systems in high-precision applications is dependent upon the dynamics of the system, as vibration can be a significant contributor to the measurement uncertainty and process variability. Technologies making use of accelerometers and laser vibrometers are available to rapidly measure and process structural dynamic data but the software infrastructure is yet to be available in an open source or standardised format to allow rapid inter-platform use. In this paper, we present a novel condition monitoring system, which uses commercially available accelerometers in combination with a control-monitoring infrastructure to allow for the appraisal of the performance of a measurement or manufacturing system. A field-programmable gate array (FPGA)-based control system is implemented for high-speed data acquisition and signal processing of six triaxial accelerometers, with a frequency range of 1 Hz to 6000 Hz, a sensitivity of 102.5 mV/ms−2 and a maximum sample rate of 12,800 samples per second per channel. The system includes two methods of operation: real-time performance monitoring and detailed measurement/manufacturing verification. A lathe condition monitoring investigation is undertaken to demonstrate the utility of this system and acquire typical machining performance parameters in order to monitor the “health” of the system. Full article
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8 pages, 2700 KiB  
Article
Development of a Device Compatible with Universal Testing Machine to Perform Hole Expansion and Erichsen Cupping Tests
by Rafael O. Santos, António B. Pereira, Marilena C. Butuc, Gabriela Vincze, António J. Festas and Luciano P. Moreira
Machines 2020, 8(1), 2; https://doi.org/10.3390/machines8010002 - 30 Dec 2019
Cited by 5 | Viewed by 4942
Abstract
The material characterization regarding sheet metal formability is usually assessed by the forming limit curve (FLC). The FLC requires specialized and expensive equipment, several samples with different geometries, and can be a very time-consuming procedure for data treatment. Alternatively, the hole expansion test [...] Read more.
The material characterization regarding sheet metal formability is usually assessed by the forming limit curve (FLC). The FLC requires specialized and expensive equipment, several samples with different geometries, and can be a very time-consuming procedure for data treatment. Alternatively, the hole expansion test (HET) and the Erichsen Cupping Test (ECT) can be used for routine evaluations of sheet metal mechanical behavior. These formability tests require fewer quantities of material and easy specimen preparation with a fast analysis of results. The HET and ECT procedures provide a proper evaluation of sheet material stretch-flangeability, formability, strength, and ductility. In this work, we developed a low-cost mechanical device capable of performing the HET and ECT tests using a universal testing machine. The equipment is designed to meet the test parameters set by ISO 16630 (HET) and ISO 20482 (ECT) standards. In order to verify its functionality, tests were carried out with the dual-phase steels DP600 and DP780. The corresponding values determined for the hole expansion ratio and the Erichsen index provided reliable results in terms of the accuracy and repeatability of the proposed testing device. Full article
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16 pages, 6324 KiB  
Article
Optimization of the Manufacturing Strategy, Machining Conditions, and Finishing of a Radial Impeller
by Fotios I. Stratogiannis, Nikolaos I. Galanis, Nikolaos E. Karkalos and Angelos P. Markopoulos
Machines 2020, 8(1), 1; https://doi.org/10.3390/machines8010001 - 27 Dec 2019
Cited by 13 | Viewed by 4518
Abstract
Impellers are the most crucial components of pumps, as they directly determine the velocity profile of the fluid flowing through the pump and its efficiency. Given that the impellers have a complex geometry, they pose an important challenge to the manufacturer in order [...] Read more.
Impellers are the most crucial components of pumps, as they directly determine the velocity profile of the fluid flowing through the pump and its efficiency. Given that the impellers have a complex geometry, they pose an important challenge to the manufacturer in order to construct them with the best possible dimensional accuracy and surface quality, and also achieve short machining times. In the present paper, the machining operations for the manufacture of a radial impeller were designed and implemented for the case of a single-entry semi-closed radial flow impeller. At first, the best milling strategies, optimum cutting conditions, and appropriate cutting tools were selected for each of the three machining phases, namely, roughing, semi-finishing, and finishing. Then, an experimental investigation was conducted, especially for the optimum process conditions during finishing of impeller blades, using Taguchi L16 orthogonal array. After the analysis of surface roughness was conducted for the 16 experiments, it was found that the most important parameters were spindle speed and feed. Furthermore, the optimum settings were determined as the maximum spindle speed and the lowest feed per tooth value and a regression model correlating process parameters with surface roughness was established with a high degree of accuracy. Full article
(This article belongs to the Special Issue Advances in CAD/CAM/CAE Technologies)
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