Machines

19 pages, 5689 KiB

Open AccessArticle

Torque Characteristics of the Revolving Vane Air Expander

by Kuan Thai Aw, Alison Subiantoro and Kim Tiow Ooi

Machines 2020, 8(3), 58; https://doi.org/10.3390/machines8030058 - 17 Sep 2020

Viewed by 2758

The use of compressed air as an alternative source of clean energy requires an air expander to extract work. A new design, known as the revolving vane mechanism, has been proposed in an effort to develop high efficiency rotary machines. This paper provides [...] Read more.

The use of compressed air as an alternative source of clean energy requires an air expander to extract work. A new design, known as the revolving vane mechanism, has been proposed in an effort to develop high efficiency rotary machines. This paper provides an in-depth analysis by including the vibration characteristics of the revolving vane air expander to evaluate the steady-state operating output torque. A generic model for describing the revolving vane rotational vibration is first derived and subsequently modified to describe the prototype tested. Measurements show that the output torque is bimodal; arising from a tolerance gap between the vane and its slot during fabrication. This effect was found to be less pronounced at high operating speeds. The model is found to be in good agreement with the measured output torques. Further analysis with the validated model showed that extracting shaft work from the cylinder would result in better performance. Full article

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12 pages, 1522 KiB

Open AccessArticle

Research of a Flexible Space-Vector-Based Hybrid PWM Transition Algorithm between SHEPWM and SHMPWM for Three-Level NPC Inverters

by Tao Jing, Andrey Radionov, Alexander Maklakov and Vadim Gasiyarov

Machines 2020, 8(3), 57; https://doi.org/10.3390/machines8030057 - 17 Sep 2020

Cited by 8 | Viewed by 2255

Abstract

In this paper, one model of flexible space-vector-based hybrid pulse width modulation (HPWM) transition algorithm consisting of selective harmonic elimination pulse width modulation (SHEPWM) and selective harmonic mitigation pulse width modulation (SHMPWM) is applied and examined in a 10kV grid with a three-level [...] Read more.

In this paper, one model of flexible space-vector-based hybrid pulse width modulation (HPWM) transition algorithm consisting of selective harmonic elimination pulse width modulation (SHEPWM) and selective harmonic mitigation pulse width modulation (SHMPWM) is applied and examined in a 10kV grid with a three-level neutral point clamped (3L-NPC) grid-connected inverter. These two modulation techniques are used to produce the appropriate firing pulses for 3L-NPC grid-connected inverters in different cases. SHMPWM is adopted to the grid-connected inverters to mitigate the required odd non-triplen harmonics according to the requirements of grid codes EN 50160 and CIGRE WG 36-05, while the firing pulses generated using SHEPWM is used to eliminate the primary low-order odd non-triplen harmonics completely. Meanwhile, one smooth and fast transition scheme is proposed by providing a suitable switching angles set at the transition point. Finally, it is demonstrated and validated by the MATLAB/SIMULINK model that smooth and quick transition is realized and there is no sudden change of current during the transition, as expected. Furthermore, this hybrid PWM technique is universal for different PWM methods based on the specific operating conditions. Full article

(This article belongs to the Special Issue Selected Papers from the ICIEAM 2020 Conference)

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15 pages, 8335 KiB

Open AccessEditor’s ChoiceArticle

Gallium Nitride Inverter Design with Compatible Snubber Circuits for Implementing Wireless Charging of Electric Vehicle Batteries

by Fatemeh Rahmani, Payam Niknejad, Tanushree Agarwal and Mohammadreza Barzegaran

Machines 2020, 8(3), 56; https://doi.org/10.3390/machines8030056 - 15 Sep 2020

Cited by 10 | Viewed by 3628

Abstract

High-frequency wireless power transfer (WPT) technology provides superior compatibility in the alignment with various WPT standards. However, high-efficiency and compact single-phase power switching systems with ideal snubber circuits are required for maximum power transfer capability. This research aims to develop an inverter using [...] Read more.

High-frequency wireless power transfer (WPT) technology provides superior compatibility in the alignment with various WPT standards. However, high-efficiency and compact single-phase power switching systems with ideal snubber circuits are required for maximum power transfer capability. This research aims to develop an inverter using Gallium Nitride (GaN) power transistors, optimized RCD (resistor/capacitor/diode) snubber circuits, and gate drivers, each benefitting WPT technology by reducing the switching and conduction loss in charging electric vehicle batteries. A full-bridge GaN inverter was simulated and instituted as part of the wireless charging circuit design. The RCD circuits were adjusted by transferring maximum power from the power supply to the transmitter inductor. For verification of the simulated output, lab-scale experiments were implemented for two half-bridges controlled by gate drivers with corresponding snubber circuits. After authenticating the output results, the GaN inverter was tested with an input range of 30 V to deduce the success of charging electric vehicle batteries within an efficient time frame. The developed inverter, at 80 kHz frequency, was applied in place of a ready-to-use evaluation board, fully reducing less harmonic distortion and greatly increasing WPT system efficiency (~93%). In turn, the designed GaN inverter boasts considerable energy savings, resulting in a more cost-effective solution for manufacturers. Full article

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20 pages, 1717 KiB

Open AccessArticle

Fuzzy-Based Fault-Tolerant Control for Omnidirectional Mobile Robot

by Ahmad M. Alshorman, Omar Alshorman, Muhammad Irfan, Adam Glowacz, Fazal Muhammad and Wahyu Caesarendra

Machines 2020, 8(3), 55; https://doi.org/10.3390/machines8030055 - 09 Sep 2020

Cited by 39 | Viewed by 5119

Abstract

The motion-planning problem is well known in robotics; it aims to find a free-obstacle path from a starting point to a destination. To make use of actuation generosity and the fuzzy fast response behavior compared to other non-linear controllers, a fuzzy-based fault-tolerant control [...] Read more.

The motion-planning problem is well known in robotics; it aims to find a free-obstacle path from a starting point to a destination. To make use of actuation generosity and the fuzzy fast response behavior compared to other non-linear controllers, a fuzzy-based fault-tolerant control for an omnidirectional mobile robot with four Mecanum wheels is proposed. The objective is to provide the robot with an online scheme to control the robot motion while moving toward the final destination with avoiding obstacles in its environment and providing an adaptive solution for a combination of one or combination of the wheel’s faults. The faults happen when the wheel does not receive the control command signal from the controller; in this case, the robot can rotate freely due to the interaction with the ground. The principle of fuzzy-based control proposed by Sugeno is used to develop the motion controller. The motion controller consists of two main controllers: the Run-To-Goal, and the obstacle-avoidance controller. The outputs of these two controllers are superposed to get the net potential force on the robot. By its simplicity, the fuzzy controller can be suitable for online applications (online path planning in our case). To the best of our knowledge, this is the first fuzzy-based fault-tolerant controller for an omnidirectional robot. The proposed controller is tested by a set of simulation scenarios to check the proposed fuzzy tolerant control. Kuka OmniRob is used as an example of the omnidirectional robot in these simulation runs. Matlab is used to build the fuzzy-based fault-tolerant control, and the 3D simulation is developed on the CoppeliaSim software. We examine five distinct scenarios, each one with a different fault state. In all scenarios, the proposed algorithm could control the robot to reach its final destination with the absence and presence of an obstacle in the workspace, despite actuator faults, without crossing the workspace boundaries. Full article

(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)

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18 pages, 13110 KiB

Open AccessEditor’s ChoiceArticle

Studying the Effect of Working Conditions on WEDM Machining Performance of Super Alloy Inconel 617

by Stefan Dzionk and Mieczysław S. Siemiątkowski

Machines 2020, 8(3), 54; https://doi.org/10.3390/machines8030054 - 09 Sep 2020

Cited by 20 | Viewed by 3136

Abstract

Wire electrical discharge machining (WEDM) has been, for many years, a precise and efficient non-conventional manufacturing solution in various industrial applications, mostly involving the use of hard-to-machine materials like, among others, the Inconel super alloys. The focus of the present study is on [...] Read more.

Wire electrical discharge machining (WEDM) has been, for many years, a precise and efficient non-conventional manufacturing solution in various industrial applications, mostly involving the use of hard-to-machine materials like, among others, the Inconel super alloys. The focus of the present study is on exploring the effect of selected control parameters, including pulse duration, pulse-off time and the dielectric flow pressure on the WEDM process performance characteristics of Inconel 617 material, such as: volumetric material removal rate (MRR), the dimensional accuracy of cutting (reflected by the kerf width) and surface roughness (SR). The research experiment has been designed and carried out using the response surface methodology (RSM) accordingly with the Box–Behnken design scheme. The results of experiments derived in the form of a fitted regression model have been subjected to the analysis of variance (ANOVA) tests. Thus, the variable process parameters and the relevant interactions between them, characterized by a significant influence on the values of the derived output responses, could be explicitly determined. Full article

(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining)

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15 pages, 4787 KiB

Open AccessArticle

Automation of the Leonardo da Vinci Machines

by Maide Bucolo, Arturo Buscarino, Carlo Famoso, Luigi Fortuna and Salvina Gagliano

Machines 2020, 8(3), 53; https://doi.org/10.3390/machines8030053 - 04 Sep 2020

Cited by 13 | Viewed by 5693

Abstract

Leonardo da Vinci inventions and projects represent an intriguing starting point to remark the concept that innovation must be considered as a continuous route towards evolution in history. Some of the particular ideas and innovations presented by Leonardo da Vinci led us to [...] Read more.

Leonardo da Vinci inventions and projects represent an intriguing starting point to remark the concept that innovation must be considered as a continuous route towards evolution in history. Some of the particular ideas and innovations presented by Leonardo da Vinci led us to formulate a link with automatic control. Selected models of the Leonardo da Vinci machines are presented in this paper, taking strictly into account the original mechanical schemes and working principles, but introducing modern low-cost control equipment, emphasizing the role of automatic control and that of electronic control devices, such as microcontrollers, sensors, and communication devices, to completely automate the Leonardo da Vinci machines. The approach outlined in the paper can be applied not only to other Leonardo machines but also to other mechanical equipment not necessarily designed by Leonardo da Vinci. Moreover, it is useful to remark that the approach followed in this paper can be very important also to introduce students, leading by example, to concepts typical of automation and for assisting in learning, keeping in mind the practical applications of advanced automation principles. The main research task of this paper is proving the efficacy of modern digital control techniques and teleoperation in strongly classical mechanical Leonardo machines, remarking that the projects of Leonardo are prompt to be efficiently controlled. This task could not be explored by Leonardo himself due to the lack of control technology. Moreover, the paper is addressed also to stimulate the young generations of engineers in joining classical mechanics with advanced technology. Therefore, the paper is also devoted to give focus on the fact that the Leonardo machines encompass all the key aspects of modern system engineering. Full article

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13 pages, 1868 KiB

Open AccessArticle

Investigation of the Mechanical Properties of a Carbon Fibre-Reinforced Nylon Filament for 3D Printing

by Flaviana Calignano, Massimo Lorusso, Ignanio Roppolo and Paolo Minetola

Machines 2020, 8(3), 52; https://doi.org/10.3390/machines8030052 - 04 Sep 2020

Cited by 53 | Viewed by 6582

Abstract

Additive manufacturing (i.e., 3D printing) has rapidly developed in recent years. In the recent past, many researchers have highlighted the development of in-house filaments for fused filament fabrication (FFF), which can extend the corresponding field of application. Due to the limited mechanical properties [...] Read more.

Additive manufacturing (i.e., 3D printing) has rapidly developed in recent years. In the recent past, many researchers have highlighted the development of in-house filaments for fused filament fabrication (FFF), which can extend the corresponding field of application. Due to the limited mechanical properties and deficient functionality of printed polymer parts, there is a need to develop printable polymer composites that exhibit high performance. This study analyses the actual mechanical characteristics of parts fabricated with a low-cost printer from a carbon fibre-reinforced nylon filament. The results show that the obtained values differ considerably from the values presented in the datasheets of various filament suppliers. Moreover, the hardness and tensile strength are influenced by the building direction, the infill percentage, and the thermal stresses, whereas the resilience is affected only by the building direction. Furthermore, the relationship between the mechanical properties and the filling factor is not linear. Full article

(This article belongs to the Section Advanced Manufacturing)

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25 pages, 4113 KiB

Open AccessArticle

Automotive Lightweight Design: Simulation Modeling of Mass-Related Consumption for Electric Vehicles

by Francesco Del Pero, Lorenzo Berzi, Andrea Antonacci and Massimo Delogu

Machines 2020, 8(3), 51; https://doi.org/10.3390/machines8030051 - 03 Sep 2020

Cited by 20 | Viewed by 5946

Abstract

A thorough assessment of Life-Cycle effects involved by vehicle lightweighting needs a rigorous evaluation of mass-induced consumption, on which energy and sustainability benefits during use stage directly depend. The paper proposes an analytical calculation procedure to estimate the weight-related energy consumption of pure [...] Read more.

A thorough assessment of Life-Cycle effects involved by vehicle lightweighting needs a rigorous evaluation of mass-induced consumption, on which energy and sustainability benefits during use stage directly depend. The paper proposes an analytical calculation procedure to estimate the weight-related energy consumption of pure Electric Vehicles (EVs), since existing literature leaves considerable room for improvement regarding this research area. The correlation between consumption and mass is expressed through the Energy Reduction Value (ERV) coefficient, which quantifies the specific consumption saving achievable through 100 kg mass reduction. The ERV is estimated for a number of heterogeneous case studies derived from real 2019 European market EV models and according to three drive cycles, to consider different driving behaviors. For the case studies under consideration, ERV ranges from 0.47 to 1.17 kWh/(100 km × 100 kg), with the variability mainly depending on vehicle size and driving cycle. Given the high uncertainty of mass-related consumption on car size, an analytical method is refined to estimate accurately the ERV for any real-world EV model, starting from vehicle technical features. Along with energy assessment, the research also evaluates the environmental implications of lightweight design by means of the Impact Reduction Value (IRV), which is estimated for three distinct electricity grid mixes. Finally, the ERV/IRV modeling approach is applied to a series of comparative lightweight case studies taken from the literature. Such an application demonstrates the effective utility of the work to reduce the uncertainty for all cases where no physical tests or computer-aided simulations are available. Full article

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13 pages, 2477 KiB

Open AccessArticle

Weight-Vibration Pareto Optimization of a Triple Mass Flywheel for Heavy-Duty Truck Powertrains

by Viktor Berbyuk

Machines 2020, 8(3), 50; https://doi.org/10.3390/machines8030050 - 31 Aug 2020

Cited by 6 | Viewed by 2436

Abstract

Enhanced efficiency of heavy-duty truck powertrains with constraints imposed on noise, vibration, and harshness requires novel solutions for torsion vibrations attenuation. In the paper, the weight-vibration Pareto optimization problem for a novel vibration absorber, a triple mass flywheel, for application in heavy-duty truck [...] Read more.

Enhanced efficiency of heavy-duty truck powertrains with constraints imposed on noise, vibration, and harshness requires novel solutions for torsion vibrations attenuation. In the paper, the weight-vibration Pareto optimization problem for a novel vibration absorber, a triple mass flywheel, for application in heavy-duty truck powertrains is considered. Global sensitivity analysis and Pareto optimization method are used to design a novel vibration absorber. The optimization method attempts to minimize oscillations of the torque at the transmission input shaft as well as to minimize total mass inertia of the absorber. It is shown that there exists a Pareto front between the measure of the attenuation of oscillations of the torque and the total mass inertia of a triple mass flywheel. The optimized design parameters for the absorber are obtained that provide the best attenuation of oscillations of the torque at the transmission input shaft for different mean values of the engine driving torque. The analysis shows real evidence of the feasibility of the application of this concept of vibration absorbers in heavy-duty truck powertrains. It is also shown that optimized design parameters of a triple mass flywheel put this concept in a superior position in comparison with a dual mass flywheel. Full article

(This article belongs to the Section Machines Testing and Maintenance)

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19 pages, 2122 KiB

Open AccessArticle

A Cost-Effective Person-Following System for Assistive Unmanned Vehicles with Deep Learning at the Edge

by Anna Boschi, Francesco Salvetti, Vittorio Mazzia and Marcello Chiaberge

Machines 2020, 8(3), 49; https://doi.org/10.3390/machines8030049 - 28 Aug 2020

Cited by 11 | Viewed by 4656

Abstract

The vital statistics of the last century highlight a sharp increment of the average age of the world population with a consequent growth of the number of older people. Service robotics applications have the potentiality to provide systems and tools to support the [...] Read more.

The vital statistics of the last century highlight a sharp increment of the average age of the world population with a consequent growth of the number of older people. Service robotics applications have the potentiality to provide systems and tools to support the autonomous and self-sufficient older adults in their houses in everyday life, thereby avoiding the task of monitoring them with third parties. In this context, we propose a cost-effective modular solution to detect and follow a person in an indoor, domestic environment. We exploited the latest advancements in deep learning optimization techniques, and we compared different neural network accelerators to provide a robust and flexible person-following system at the edge. Our proposed cost-effective and power-efficient solution is fully-integrable with pre-existing navigation stacks and creates the foundations for the development of fully-autonomous and self-contained service robotics applications. Full article

(This article belongs to the Special Issue Latest Trends of Autonomous Aerial and Terrestrial Vehicles for Service Robotics Applications)

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16 pages, 2777 KiB

Open AccessArticle

Analysis of a Wearable Robotic System for Ankle Rehabilitation

by Matteo Russo and Marco Ceccarelli

Machines 2020, 8(3), 48; https://doi.org/10.3390/machines8030048 - 27 Aug 2020

Cited by 35 | Viewed by 5207

Abstract

As one of the most commonly injured joints of the human body, the ankle is often subject to sprains or fractures that require motion assistance to recover mobility. Whereas physiotherapists usually perform rehabilitation in one-on-one sessions with patients, several successful robotic rehabilitation solutions [...] Read more.

As one of the most commonly injured joints of the human body, the ankle is often subject to sprains or fractures that require motion assistance to recover mobility. Whereas physiotherapists usually perform rehabilitation in one-on-one sessions with patients, several successful robotic rehabilitation solutions have been proposed in the last years. However, their design is usually bulky and requires the patient to sit or stand in a static position. A lightweight wearable device for ankle motion assistance, the CABLEankle, is here proposed for motion ankle exercising in rehabilitation and training. The CABLEankle is based on a cable-driven S-4SPS parallel architecture, which enables motion assistance over the large motion range of the human ankle in a walking gait. The proposed mechanism design is analyzed with kinematic and static models, and the force closure workspace of the mechanism is discussed with analytical results. Finally, the feasibility of the proposed design is investigated through numerical simulations over the ankle motion range as a characterization of the peculiar motion. Full article

(This article belongs to the Special Issue Italian Advances on MMS)

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18 pages, 7148 KiB

Open AccessArticle

Development and Testing of a Methodology for the Assessment of Acceptability of LKA Systems

by Luca Salvati, Matteo d’Amore, Anita Fiorentino, Arcangelo Pellegrino, Pasquale Sena and Francesco Villecco

Machines 2020, 8(3), 47; https://doi.org/10.3390/machines8030047 - 19 Aug 2020

Cited by 28 | Viewed by 2643

Abstract

In recent years, driving simulators have been widely used by automotive manufacturers and researchers in human-in-the-loop experiments, because they can reduce time and prototyping costs, and provide unlimited parametrization, more safety, and higher repeatability. Simulators play an important role in studies about driver [...] Read more.

In recent years, driving simulators have been widely used by automotive manufacturers and researchers in human-in-the-loop experiments, because they can reduce time and prototyping costs, and provide unlimited parametrization, more safety, and higher repeatability. Simulators play an important role in studies about driver behavior in operating conditions or with unstable vehicles. The aim of the research is to study the effects that the force feedback (f.f.b.), provided to steering wheel by a lane-keeping-assist (LKA) system, has on a driver’s response in simulators. The steering’s force feedback system is tested by reproducing the conditions of criticality of the LKA system in order to minimize the distance required to recover the driving stability as a function of set f.f.b. intensity and speed. The results, obtained in three specific criticality conditions, show that the behaviour of the LKA system, reproduced in the simulator, is not immediately understood by the driver and, sometimes, it is in opposition with the interventions performed by the driver to ensure driving safety. The results also compare the performance of the subjects, either overall and classified into subgroups, with reference to the perception of the LKA system, evaluated by means of a questionnaire. The proposed experimental methodology is to be regarded as a contribution for the integration of acceptance tests in the evaluation of automation systems. Full article

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22 pages, 15912 KiB

Open AccessArticle

Model-Based Manipulation of Linear Flexible Objects: Task Automation in Simulation and Real World

by Peng Chang and Taşkın Padır

Machines 2020, 8(3), 46; https://doi.org/10.3390/machines8030046 - 08 Aug 2020

Cited by 16 | Viewed by 5126

Abstract

Manipulation of deformable objects is a desired skill in making robots ubiquitous in manufacturing, service, healthcare, and security. Common deformable objects (e.g., wires, clothes, bed sheets, etc.) are significantly more difficult to model than rigid objects. In this research, we contribute to the [...] Read more.

Manipulation of deformable objects is a desired skill in making robots ubiquitous in manufacturing, service, healthcare, and security. Common deformable objects (e.g., wires, clothes, bed sheets, etc.) are significantly more difficult to model than rigid objects. In this research, we contribute to the model-based manipulation of linear flexible objects such as cables. We propose a 3D geometric model of the linear flexible object that is subject to gravity and a physical model with multiple links connected by revolute joints and identified model parameters. These models enable task automation in manipulating linear flexible objects both in simulation and real world. To bridge the gap between simulation and real world and build a close-to-reality simulation of flexible objects, we propose a new strategy called Simulation-to-Real-to-Simulation (Sim2Real2Sim). We demonstrate the feasibility of our approach by completing the Plug Task used in the 2015 DARPA Robotics Challenge Finals both in simulation and real world, which involves unplugging a power cable from one socket and plugging it into another. Numerical experiments are implemented to validate our approach. Full article

(This article belongs to the Special Issue Intelligent Mechatronics Systems)

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18 pages, 5953 KiB

Open AccessArticle

Rehabilitation Machine for Bariatric Individuals

by Andrea Botta, Paride Cavallone, Luca Carbonari, Carmen Visconte and Giuseppe Quaglia

Machines 2020, 8(3), 45; https://doi.org/10.3390/machines8030045 - 07 Aug 2020

Cited by 2 | Viewed by 2225

Abstract

Obesity is known to be growing worldwide. The World Health Organization (WHO) reports that obesity has tripled since 1975. In 2016, 39% of adults over 18 years old were overweight, and 13% were obese. Obesity is mostly preventable by adopting lifestyle improvements, enhancing [...] Read more.

Obesity is known to be growing worldwide. The World Health Organization (WHO) reports that obesity has tripled since 1975. In 2016, 39% of adults over 18 years old were overweight, and 13% were obese. Obesity is mostly preventable by adopting lifestyle improvements, enhancing diet quality, and doing physical exercise. The workload of the physical exercises should be proportionate to the patient’s capabilities. However, it must be considered that obese people are not used to training; they may not endure physical exertion and, even more critically, they could have some psychological impediments to the workouts. Physical exercises and equipment must, therefore, guarantee comfort and prevent situations in which the bariatric individual may feel inadequate. For these reasons, this study aims to design an innovative system to approach simple physical activities, like leg and arm exercises, to bariatric users to enable them to recover mobility and muscle tone gradually. The leading feature of this architecture is the design of hidden exercise mechanisms to overcome the psychological barriers of the users toward these kinds of machines. This paper proposes the initial design of the main sub-systems composing the rehabilitation machine, namely the leg curl and leg extension mechanism and its control architecture, the upper body exercises system, and a series of regulation mechanisms required to accommodate a wide range of users. The proposed functional design will then lead to the development of a prototype to validate the machine. Full article

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20 pages, 5518 KiB

Open AccessEditor’s ChoiceArticle

Advanced Strategy of Speed Predictive Control for Nonlinear Synchronous Reluctance Motors

by Ahmed Farhan, Mohamed Abdelrahem, Christoph M. Hackl, Ralph Kennel, Adel Shaltout and Amr Saleh

Machines 2020, 8(3), 44; https://doi.org/10.3390/machines8030044 - 01 Aug 2020

Cited by 17 | Viewed by 3209

Abstract

To gain fast dynamic response, high performance, and good tracking capability, several control strategies have been applied to synchronous reluctance motors (SynRMs). In this paper, a nonlinear advanced strategy of speed predictive control (SPC) based on the finite control set model predictive control [...] Read more.

To gain fast dynamic response, high performance, and good tracking capability, several control strategies have been applied to synchronous reluctance motors (SynRMs). In this paper, a nonlinear advanced strategy of speed predictive control (SPC) based on the finite control set model predictive control (FCS-MPC) is proposed and simulated for nonlinear SynRMs. The SPC overcomes the limitation of the cascaded control structure of the common vector control by employing a novel strategy that considers all the electrical and mechanical variables in one control law through a new cost function to obtain the switching signals for the power converter. The SynRM flux maps are known based on finite element method (FEM) analysis to take into consideration the effect of the nonlinearity of the machine. To clear the proposed strategy features, a functional and qualitative comparison between the proposed SPC, field-oriented control (FOC) with an anti-windup scheme, and current predictive control (CPC) with outer PI speed control loop is presented. For simplicity, particle swarm optimization (PSO) is performed to tune all the unknown parameters of the control strategies. The comparison features include controller design, dynamic and steady-state behaviors. Simulation results are presented to investigate the benefits and limitations of the three control strategies. Finally, the proposed SPC, FOC, and CPC have their own merits, and all methods encounter the requirements of advanced high-performance drives. Full article

(This article belongs to the Special Issue Design and Control of Rotating Electrical Machines)

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27 pages, 5891 KiB

Open AccessArticle

Roller Leveler Monitoring Using Acceleration Measurements and Models for Steel Strip Properties

by Riku-Pekka Nikula and Kauko Leiviskä

Machines 2020, 8(3), 43; https://doi.org/10.3390/machines8030043 - 29 Jul 2020

Cited by 1 | Viewed by 3748

Abstract

The advanced steel grades and high productivity requirements in the modern steel industry subject production machines to increased mechanical stresses, which inflicts losses. Novel data-oriented solutions to the monitoring of machines have a pivotal role in loss prevention, but the industrial data with [...] Read more.

The advanced steel grades and high productivity requirements in the modern steel industry subject production machines to increased mechanical stresses, which inflicts losses. Novel data-oriented solutions to the monitoring of machines have a pivotal role in loss prevention, but the industrial data with high sampling rates, noise, and dimensions bring challenges there. This study proposes a new monitoring approach for roller levelers based on vibration measurements and regression models for estimating steel strip properties including yield strength, width, and thickness. The regression residuals are monitored based on moving mean and range charts, which reveal changes from the expected normal operation. A high-dimensional feature set of 144,000 statistical features was studied with various feature selection methods, including filters and wrappers. Multiple linear regression and generalized regression neural network were applied in modeling. The approach was validated using data from an industrial roller leveler processing steel strips with diverse properties. The results reveal that the accurate prediction of the strip thickness from the strip properties is possible and multiple linear regression was generally the superior model therein. Additional simulations indicated that the control charts can detect deviant operation. Supplemental information about the momentary operation of the machine would improve the approach. Full article

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14 pages, 4313 KiB

Open AccessArticle

Surface Hardening of Machine Parts Using Nitriding and TiN Coating Deposition in Glow Discharge

by Alexander Metel, Sergey Grigoriev, Yury Melnik, Marina Volosova and Enver Mustafaev

Machines 2020, 8(3), 42; https://doi.org/10.3390/machines8030042 - 24 Jul 2020

Cited by 8 | Viewed by 2154

Abstract

Surface hardening of machine parts substantially improves their performance. The best results are obtained when combined hardening consists of surface nitriding and subsequent deposition of hard coatings. The nitriding of machine parts immersed in the plasma of glow coatings have been studied, and [...] Read more.

Surface hardening of machine parts substantially improves their performance. The best results are obtained when combined hardening consists of surface nitriding and subsequent deposition of hard coatings. The nitriding of machine parts immersed in the plasma of glow coatings have been studied, and the study results are presented. Titanium atoms for coating synthesis are obtained via titanium evaporation in a hollow molybdenum anode of the discharge. Stable evaporation of titanium occurs only when the power density of electrons heating the liquid titanium does not exceed ~500 W/cm². To start evaporation, it is only necessary to reduce the gas pressure to 0.02 Pa. To stop evaporation, it is enough to increase the gas pressure to 0.1 Pa. Fast argon and nitrogen atoms used for cleaning the machine parts, heating them, and bombarding the growing coating are obtained using a grid composed of plane-parallel plates under high negative voltage and immersed in plasma. Full article

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16 pages, 659 KiB

Open AccessArticle

Automated Kinematic Analysis of Closed-Loop Planar Link Mechanisms

by Tatsuya Yamamoto, Nobuyuki Iwatsuki and Ikuma Ikeda

Machines 2020, 8(3), 41; https://doi.org/10.3390/machines8030041 - 23 Jul 2020

Cited by 5 | Viewed by 4610

Abstract

The systematic kinematic analysis method for planar link mechanisms based on their unique procedures can clearly show the analysis process. The analysis procedure is expressed by a combination of many kinds of conversion functions proposed as the minimum calculation units for analyzing a [...] Read more.

The systematic kinematic analysis method for planar link mechanisms based on their unique procedures can clearly show the analysis process. The analysis procedure is expressed by a combination of many kinds of conversion functions proposed as the minimum calculation units for analyzing a part of the mechanism. When it is desired to perform this systematic kinematics analysis for a specific linkage mechanism, expert researchers can accomplish the analysis by searching for the procedure by themselves, however, it is difficult for non-expert users to find the procedure. This paper proposes the automatic procedure extraction algorithm for the systematic kinematic analysis of closed-loop planar link mechanisms. By limiting the types of conversion functions to only geometric calculations that are related to the two-link chain, the analysis procedure can be represented by only one type transformation function, and the procedure extraction algorithm can be described as a algorithm searching computable 2-link chain. The configuration of mechanism is described as the “LJ-matrix”, which shows the relationship of connections between links with pairs. The algorithm consists of four sub-processes, namely, “LJ-matrix generator”, “Solver process”, “Add-link process”, and “Over-constraint resolver”. Inputting the sketch of the mechanism into the proposed algorithm, it automatically extracts unique analysis procedure and generate a kinematic analysis program as a MATLAB code based on it. Several mechanisms are analyzed as examples to show the usefulness of the proposed method. Full article

(This article belongs to the Special Issue Selected Papers from Advances of Japanese Machine Design)

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15 pages, 6514 KiB

Open AccessArticle

Biaxial Testing Machine: Development and Evaluation

by António B. Pereira, Fábio A.O. Fernandes, Alfredo B. de Morais and João Maio

Machines 2020, 8(3), 40; https://doi.org/10.3390/machines8030040 - 21 Jul 2020

Cited by 10 | Viewed by 5901

Abstract

Biaxial mechanical testing gained increased importance for characterization of materials that present anisotropic behavior and/or different responses when subjected to tensile and compression loadings. In this work, a new biaxial testing machine was developed. The various systems and components were designed, manufactured, assembled, [...] Read more.

Biaxial mechanical testing gained increased importance for characterization of materials that present anisotropic behavior and/or different responses when subjected to tensile and compression loadings. In this work, a new biaxial testing machine was developed. The various systems and components were designed, manufactured, assembled, and assessed. Uniaxial tensile tests were performed to validate the device, showing results consistent with those obtained on a universal testing machine. Finally, biaxial tensile tests were also performed on polypropylene cruciform specimens. The results revealed high precision levels, thus showing the potential of this new machine. Full article

(This article belongs to the Section Machines Testing and Maintenance)

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22 pages, 10643 KiB

Open AccessArticle

Unbalance Estimation for a Large Flexible Rotor Using Force and Displacement Minimization

by Tuhin Choudhury, Risto Viitala, Emil Kurvinen, Raine Viitala and Jussi Sopanen

Machines 2020, 8(3), 39; https://doi.org/10.3390/machines8030039 - 14 Jul 2020

Cited by 10 | Viewed by 5336

Abstract

Mass unbalance is one of the most prominent faults that occurs in rotating machines. The identification of unbalance in the case of large flexible rotors is crucial because in industrial applications such as paper machines and roll grinders, high vibrations can adversely affect [...] Read more.

Mass unbalance is one of the most prominent faults that occurs in rotating machines. The identification of unbalance in the case of large flexible rotors is crucial because in industrial applications such as paper machines and roll grinders, high vibrations can adversely affect the quality of the end product. The objective of this research is to determine the unbalance location, magnitude and phase for a large flexible rotor with few measured coordinates. To this end, an established force-based method comprising of modal expansion and equivalent load minimization is applied. Due to the anisotropic behavior of the test rotor, the force method required at least six measured coordinates to predict the unbalance with an error of 4 to 36%. To overcome this limitation, an alternate method, eliminating the use of modal expansion, is proposed. Here, displacements generated by varying the location of a reference unbalance along the rotor axis, are compared to measured displacements to detect the unbalance location. Furthermore, instead of force-based fault models, the minimization of displacements at measured locations determines the unbalance parameters. The test case in this study is the guiding roll of a paper machine and its different unbalance states. The algorithm is tested initially with a simulation-based model and then validated with an experimental set up. The results show that the displacement method can locate the unbalance close to the actual location and it can predict the unbalance magnitude and phase with only two measured coordinates. Lastly, using measured data from 15 measurement points across the tube section of the test rotor, a comparison shows how the selection of the two measured locations affects the estimation accuracy. Full article

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25 pages, 8102 KiB

Open AccessArticle

A Novel Adaptive and Nonlinear Electrohydraulic Active Suspension Control System with Zero Dynamic Tire Liftoff

by Amhmed Mohamed Al Aela, Jean-Pierre Kenne and Honorine Angue Mintsa

Machines 2020, 8(3), 38; https://doi.org/10.3390/machines8030038 - 11 Jul 2020

Cited by 10 | Viewed by 3320

Abstract

In this paper, a novel adaptive control system (NAC) is proposed for a restricted quarter-car electrohydraulic active suspension system. The main contribution of this NAC is its explicit tackling of the trade-off between passenger comfort/road holding and passenger comfort/suspension travel. Reducing suspension travel [...] Read more.

In this paper, a novel adaptive control system (NAC) is proposed for a restricted quarter-car electrohydraulic active suspension system. The main contribution of this NAC is its explicit tackling of the trade-off between passenger comfort/road holding and passenger comfort/suspension travel. Reducing suspension travel oscillations is another control target that was considered. Many researchers have developed control laws for constrained active suspension systems. However, most of the studies in the works of the latter have not directly examined the compromise between road holding, suspension travel, and passenger comfort. In this study, we proposed a novel adaptive control system to explicitly address the trade-off between passenger comfort and road holding, as well as the compromise between passenger comfort and suspension travel limits. The novelty of our control technique lies in its introduction of a modeling system for a dynamic landing tire system aimed at avoiding a dynamic tire liftoff. The proposed control consists of an adaptive neural networks’ backstepping control, coupled with a nonlinear control filter system aimed at tracking the output position of the nonlinear filter. The tracking control position is the difference between the sprung mass position and the output nonlinear filter signal. The results indicate that the novel adaptive control (NAC) can achieve the handling of car–road stability, ride comfort, and safe suspension travel compared to that of the other studies, demonstrating the controller’s effectiveness. Full article

(This article belongs to the Special Issue Intelligent Mechatronics Systems)

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19 pages, 1667 KiB

Open AccessReview

Sources of Excitation and Models for Cylindrical Gear Dynamics: A Review

by Fabio Bruzzone and Carlo Rosso

Machines 2020, 8(3), 37; https://doi.org/10.3390/machines8030037 - 01 Jul 2020

Cited by 12 | Viewed by 4253

Abstract

In this paper, a review of the evolution of the study of cylindrical gear dynamics is presented. After a brief historical introduction to the field, the first attempts to describe the complex interactions in those systems are analyzed introducing the dynamic factor and [...] Read more.

In this paper, a review of the evolution of the study of cylindrical gear dynamics is presented. After a brief historical introduction to the field, the first attempts to describe the complex interactions in those systems are analyzed introducing the dynamic factor and the first methodologies used to compute it. Next, the sources of excitation in geared systems are analyzed in detail and the models of the various contributions are discussed. Then, the paper focuses on the use of those sources in several dynamic models which are wildly different in terms of scope, applicability, complexity and methodology employed, ranging from simple analytical models, to lumped masses models up to multibody and finite element models. Finally, an outlook to the future evolution of the field is given and conclusions are drawn. Full article

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12 pages, 3802 KiB

Open AccessArticle

Electrical Discharge Machining with SiC Powder-Mixed Dielectric: An Effective Application in the Machining Process of Hardened 90CrSi Steel

by Thi-Hong Tran, Manh-Cuong Nguyen, Anh-Tung Luu, The-Vinh Do, Thu-Quy Le, Trung-Tuyen Vu, Ngoc-Giang Tran, Thi-Tam Do and Ngoc-Pi Vu

Machines 2020, 8(3), 36; https://doi.org/10.3390/machines8030036 - 01 Jul 2020

Cited by 20 | Viewed by 3334

Abstract

As a successful solution applied to electrical discharge machining (EDM), powder-mixed electrical discharge machining (PMEDM) has been proposed as an upgrade of the EDM process. The optimization of the process parameters of PMEDM is essential and pressing. In this study, Taguchi methods and [...] Read more.

As a successful solution applied to electrical discharge machining (EDM), powder-mixed electrical discharge machining (PMEDM) has been proposed as an upgrade of the EDM process. The optimization of the process parameters of PMEDM is essential and pressing. In this study, Taguchi methods and analysis of variance (ANOVA) were used to find the main parameters affecting surface roughness in the EDM process with SiC powder-mixed-dielectric of hardened 90CrSi steel. The PMEDM parameters selected were the powder concentration, the pulse-on-time, the pulse-off-time, the pulse current, and the server voltage. It was found that SiC powder exhibits positive effects on reducing surface roughness. The roughness obtained with the optimum powder concentration of 4 g/L was reduced by 30.02% compared to that when processed by conventional EDM. Furthermore, the pulse-off-time was found to be the most influential factor that gave an important effect on surface roughness followed by the powder concentration. The EDM condition including a powder concentration of 4 g/L, a pulse-on-time of 6 µs, a pulse-off-time of 21 µs, a pulse current of 8 A, and a server voltage of 4 V resulted in the best surface roughness. Full article

(This article belongs to the Section Advanced Manufacturing)

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28 pages, 7164 KiB

Open AccessFeature PaperArticle

Motor Current Signature Analysis-Based Permanent Magnet Synchronous Motor Demagnetization Characterization and Detection

by Manel Krichen, Elhoussin Elbouchikhi, Naourez Benhadj, Mohamed Chaieb, Mohamed Benbouzid and Rafik Neji

Machines 2020, 8(3), 35; https://doi.org/10.3390/machines8030035 - 29 Jun 2020

Cited by 38 | Viewed by 4820

Abstract

Neodymium-boron (NdFeB) permanent magnets (PMs) have been widely studied in the past years since they became the material of choice in permanent magnet synchronous machines (PMSMs). Although NdFeB PMs have a better energy density than other types of magnets and are cost-effective, their [...] Read more.

Neodymium-boron (NdFeB) permanent magnets (PMs) have been widely studied in the past years since they became the material of choice in permanent magnet synchronous machines (PMSMs). Although NdFeB PMs have a better energy density than other types of magnets and are cost-effective, their magnetization is very sensitive to the PMSM operating conditions, in particular temperature, where the irreversible demagnetization degree increases over time. Therefore, it is important to characterize and diagnose demagnetization at an early stage. In this context, this paper proposes a two-step analysis study dealing with both uniform and partial demagnetization. A 2D finite element method-based (FEM) approach is used for demagnetization characterization, and then a PMSM motor current signature analysis (MCSA) approach, based on fast Fourier transform (FFT), is considered where fault cases harmonics are considered as faults indices to detect demagnetization. In some situations, the proposed two-step approach achieved results that clearly allow distinguishing and characterizing demagnetization. Indeed, a local demagnetization introduces specific sub-harmonics while a uniform demagnetization leads to the current amplitude increase for a given torque. Full article

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Machines, Volume 8, Issue 3 (September 2020) – 24 articles

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