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Machines, Volume 11, Issue 4 (April 2023) – 90 articles

Cover Story (view full-size image): Due to the temperature-sensitive characteristic of plexiglass materials, it is very crucial to maintain a constant small contact force to avoid surface burn damage and achieve good optical properties when polishing complex curved plexiglass parts. To handle this issue, a pneumatic force-controlled actuator is developed to keep the normal contact force between the polishing tool and the workpiece constant during the robotic polishing process. Meanwhile, a gravity compensation algorithm based on roll–pitch–yaw (RPY) angle calculation is given, and a fuzzy proportion–integral–derivative (PID) control strategy is subsequently adopted without steady-state errors. Finally, the experimental results show that the established robot automatic polishing system is technically feasible and has good force control accuracy for the polishing of complex curved plexiglass parts. View this paper
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Article
Performance and Wear of Diamond Honing Stones
Machines 2023, 11(4), 502; https://doi.org/10.3390/machines11040502 - 21 Apr 2023
Viewed by 559
Abstract
Honing is one of the most precise processes for the production of tribologically highly loaded cylindrical bores in different areas of technology. The honing stone specifications influence the process performance to a large extent. During machining, the honing stones are in permanent contact [...] Read more.
Honing is one of the most precise processes for the production of tribologically highly loaded cylindrical bores in different areas of technology. The honing stone specifications influence the process performance to a large extent. During machining, the honing stones are in permanent contact with the workpiece and subject to high mechanical loads. High strength steel and latest coating materials cause additional stress on the honing stones and induce increased wear. The objective is to determine process information for these material properties to support an effective process design. In experiments, the performance and the wear rates of several honing stone specifications were investigated. In this publication, the observed wear mechanisms are analysed and influencing factors for reduced wear are outlined. Full article
(This article belongs to the Special Issue Machine Tools, Advanced Machining and Ultraprecision Machining)
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Article
PSO-Based Feedrate Optimization Algorithm for Five-Axis Machining with Constraint of Contour Error
Machines 2023, 11(4), 501; https://doi.org/10.3390/machines11040501 - 21 Apr 2023
Viewed by 569
Abstract
Feedrate has a great influence on contour error in five-axis machining. Accordingly, it is of great significance to plan the time-optimal feedrate curve considering the contour error constraint to achieve high-accuracy and high-efficiency machining. Aiming at improving the error control accuracy of model [...] Read more.
Feedrate has a great influence on contour error in five-axis machining. Accordingly, it is of great significance to plan the time-optimal feedrate curve considering the contour error constraint to achieve high-accuracy and high-efficiency machining. Aiming at improving the error control accuracy of model linearization loss and optimizing the machining time, the PSO-based feedrate optimization algorithm for five-axis machining with constraint of contour error is proposed in this paper. Firstly, the relationship between parametric feedrate and contour error constraint is clarified that provides a model basis for accurately controlling contour error by optimizing the feedrate curve. Then, the feedrate optimization model, which takes the control vertices of the feedrate curve expressed by B-spline as the decision variables and minimizes the machining time as the optimization objective, is established. Subsequently, to overcome the shortcomings of low accuracy and low efficiency caused by single optimization of global control vertices, the group search particle swarm optimization (GSPSO) algorithm based on window movement is adopted to optimize the feedrate curve in segments. Finally, the effectiveness of the proposed feedrate optimization algorithm is validated by three typical test toolpaths on an open double-turntable five-axis machine tool. In light of the experiment, the proposed algorithm is able to fully release the potential of the machine tools while accurately controlling the contour error of the cutter tip and cutter orientation. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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Article
Analysis of Time-Varying Mesh Stiffness and Dynamic Response of Gear Transmission System with Pitting and Cracking Coupling Faults
Machines 2023, 11(4), 500; https://doi.org/10.3390/machines11040500 - 21 Apr 2023
Viewed by 605
Abstract
The gear transmission system is an important part of the mechanical system, so it is essential to judge its running state accurately. To solve the difficult problem of identifying the components of coupling faults, this paper derives the calculation method of gear time-varying [...] Read more.
The gear transmission system is an important part of the mechanical system, so it is essential to judge its running state accurately. To solve the difficult problem of identifying the components of coupling faults, this paper derives the calculation method of gear time-varying mesh stiffness for coupling faults of pitting and cracking based on the energy method and considering the coupling between teeth, establishes the dynamics model of two-stage gear transmission system with coupling faults and studies the influence of coupling faults on gear time-varying mesh stiffness and dynamic characteristics. The accuracy of the proposed method is verified by experiments. The results show that both pitting and cracking can lead to a reduction in mesh stiffness. The stiffness of pitting will fluctuate irregularly due to the influence of pitting on the tooth surface, while the stiffness of cracked teeth is relatively smooth. The coupling fault stiffness is dominated by more serious faults. By analyzing the periodic impact components in time domain and the sideband components around the harmonics in frequency domain the faulty gears in the transmission system can be distinguished. It provides an effective reference for the diagnosis of faulty gears. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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Article
Adaptive Quality Diagnosis Framework for Production Lines in a Smart Manufacturing Environment
Machines 2023, 11(4), 499; https://doi.org/10.3390/machines11040499 - 21 Apr 2023
Viewed by 683
Abstract
Production lines in manufacturing environments benefit from quality diagnosis methods based on learning techniques since their ability to adapt to the runtime conditions improves performance, and at the same time, difficult computational problems can be solved in real time. Predicting the divergence of [...] Read more.
Production lines in manufacturing environments benefit from quality diagnosis methods based on learning techniques since their ability to adapt to the runtime conditions improves performance, and at the same time, difficult computational problems can be solved in real time. Predicting the divergence of a product’s physical parameters from an acceptable range of values in a manufacturing line is a process that can assist in delivering consistent and high-quality output. Costs are saved by avoiding bursts of defective products in the pipeline’s output. An innovative framework for the early detection of a product’s physical parameter divergence from a specified quality range is designed and evaluated in this study. This framework is based on learning automata to find the sequences of variables that have the highest impact on the automated sensor measurements that describe the environmental conditions in the production line. It is shown by elaborate evaluation that complexity is reduced and results close to optimal are feasible, rendering the framework suitable for deployment in practice. Full article
(This article belongs to the Special Issue Advances in Digital Manufacturing)
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Article
Simple Internal Model-Based Robust Control Design for a Non-Minimum Phase Unmanned Aerial Vehicle
Machines 2023, 11(4), 498; https://doi.org/10.3390/machines11040498 - 21 Apr 2023
Viewed by 953
Abstract
Robust control has been successful in enabling flight stability and performance for UAVs. This paper presents a simple explainable robust control design for UAV platforms with non-minimum phase (NMP) zero characteristics in their model. The paper contributes to economic (simple) robust control design [...] Read more.
Robust control has been successful in enabling flight stability and performance for UAVs. This paper presents a simple explainable robust control design for UAV platforms with non-minimum phase (NMP) zero characteristics in their model. The paper contributes to economic (simple) robust control design by addressing the NMP model’s characteristics via Internal Model Control (IMC) and its impact on the UAV pitch response performance. The proposed design is compared with a Parallel Feedback Control Design (PFCD) scheme for the same vehicle platform, for fair comparison. Simulation results illustrate the achievement of the proposed control designs for the UAV platform; only the pitch control is addressed. A by-product of this work is the interpretation of different ways of manipulating the non-minimum phase plant model, so-called ‘modelling for control’, to enable the simple controller design. The work in this paper underpins the simplicity and robustness of the IMC technique for the NMP UAV platform, which further supports the explainability of the control structure relative to performance. Full article
(This article belongs to the Special Issue Dynamics and Control of UAVs)
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Article
Enhancing Positional Accuracy of the XY-Linear Stage Using Laser Tracker Feedback and IT2FLS
Machines 2023, 11(4), 497; https://doi.org/10.3390/machines11040497 - 20 Apr 2023
Viewed by 746
Abstract
This paper proposes a calibration algorithm to improve the positional accuracies of an industrial XY-linear stage. Precision positioning of these linear stages is required to maintain highly accurate object handling and manipulation. However, due to imprecisions in linear motor stages and the gearbox, [...] Read more.
This paper proposes a calibration algorithm to improve the positional accuracies of an industrial XY-linear stage. Precision positioning of these linear stages is required to maintain highly accurate object handling and manipulation. However, due to imprecisions in linear motor stages and the gearbox, static and dynamic errors exist within these manipulators that cannot be adjusted internally. In this paper, to improve the positioning accuracy of these manipulators, measurements from a laser tracker are used within an interval type-2 fuzzy logic system. The laser tracker used in this experiment is an AT960-MR, which is a highly accurate noncontact coordinate metrology equipment capable of performing highly accurate robotic measurements. To perform calibration, we use an IT2FLS to find a nonlinear correcting relationship to compensate for position errors. The IT2FLS acts on the commands given to the move stage to find the accurate position of the move stage. To train the IT2FLS, we use particle swarm optimization (PSO) for the antecedent part parameters and Moore–Penrose generalized inverse to estimate the consequent part parameters. Data are split into train/test data to test the efficacy of the proposed algorithm. It is shown that by using the proposed IT2FLS-based calibration approach, the standard deviation of the position errors can be decreased from 86.1μm to 55.9μm, which is a 35.1% improvement. Comparison results with a multilayer perceptron neural network reveal that the proposed IT2FLS-based calibration algorithm outperforms multilayer perceptron neural network for positional calibration purposes. Full article
(This article belongs to the Special Issue Design and Control of Industrial Robots)
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Article
Deep Learning to Directly Predict Compensation Values of Thermally Induced Volumetric Errors
Machines 2023, 11(4), 496; https://doi.org/10.3390/machines11040496 - 20 Apr 2023
Viewed by 783
Abstract
The activities of the rotary axes of a five-axis machine tool generate heat causing temperature changes within the machine that contribute to tool center point (TCP) deviations. Real time prediction of these thermally induced volumetric errors (TVEs) at different positions within the workspace [...] Read more.
The activities of the rotary axes of a five-axis machine tool generate heat causing temperature changes within the machine that contribute to tool center point (TCP) deviations. Real time prediction of these thermally induced volumetric errors (TVEs) at different positions within the workspace may be used for their compensation. A Stacked Long Short Term Memories (SLSTMs) model is proposed to find the relationship between the TVEs for different axis command positions and power consumptions of the rotary axes, machine’s linear and rotary axis positions. In addition, a Stacked Gated Recurrent Units (SGRUs) model is also used to predict some cases, which are the best and the worst predictions of SLSTMs to know the abilities of their predictions. Training data come from a long motion activity experiment lasting 132 h (528 measuring cycles). Adaptive moment with decoupled weight decay (AdamW) optimizer is used to strengthen the models and increase the quality of prediction. Multistep ahead prediction in the testing phase is applied to seven positions not used for training in the long activity sequence and 31 positions in a different short activity sequence of the rotary axes lasting a total of 40 h (160 cycles) to test the ability of the trained model. The testing phase with SLSTMs yields fittings between the predicted values and measured data (without using the measured values as targets) from 69.2% to 98.8%. SGRUs show performance similar to SLSTMs with no clear winner. Full article
(This article belongs to the Section Advanced Manufacturing)
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Article
Working Condition Identification Method of Wind Turbine Drivetrain
Machines 2023, 11(4), 495; https://doi.org/10.3390/machines11040495 - 20 Apr 2023
Viewed by 444
Abstract
The operation state of the wind turbine drivetrain is complex and variable, making it difficult to accurately evaluate under the drivetrain’s anomalies. In order to accurately identify the operating state of the main drivetrain, a method for working condition identification is proposed. Firstly, [...] Read more.
The operation state of the wind turbine drivetrain is complex and variable, making it difficult to accurately evaluate under the drivetrain’s anomalies. In order to accurately identify the operating state of the main drivetrain, a method for working condition identification is proposed. Firstly, appropriate working condition identification parameters are selected and distinguished from the working condition feature parameters. Secondly, the aerodynamic power prediction model is established, which solves the problem of inaccurate theoretical estimation. Finally, after the historical working conditions are classified, the working condition identification model is established, and the proposed method is analyzed and validated by cases. The results show that the method can accurately identify the working conditions, avoiding the influence of an abnormal state of drivetrain, and provide a basis for real-time state monitoring and evaluation. Full article
(This article belongs to the Special Issue Wind Turbine Technologies)
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Article
Fatigue Life of a Comb Plate Expansion Joint
Machines 2023, 11(4), 494; https://doi.org/10.3390/machines11040494 - 20 Apr 2023
Viewed by 504
Abstract
Comb-plate expansion joints are widely used in bridge construction, and their failures are mainly static strength and fatigue. This paper used a new type of comb-plate expansion joint as the research object. Firstly, the finite element models (FEM) of the comb-plate expansion joint [...] Read more.
Comb-plate expansion joints are widely used in bridge construction, and their failures are mainly static strength and fatigue. This paper used a new type of comb-plate expansion joint as the research object. Firstly, the finite element models (FEM) of the comb-plate expansion joint with minimum and maximum openings were established by Ansys software. Then, the equivalent stress, vertical deformation, and shear stress of the expansion joint under these two working conditions were checked with code. The results showed that the static strength of the expansion joints met the code requirements under both working conditions. Secondly, to investigate the service span of the comb-plate expansion joint, the fatigue life of the expansion joint was predicted using nCode DesignLife software, and the results showed that the minimum fatigue life of the expansion joint was 2.012 × 106 times, which is higher than the 2 × 106 times specified in the code. Finally, a fatigue test of 2 million times was carried out on the full-size expansion joint. Failure modes such as deformation, fracture, or breakage hardly appeared after the fatigue test, demonstrating the reliability of this new type of comb-plate expansion joint. Full article
(This article belongs to the Section Machine Design and Theory)
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Article
Optimal Selection of the Mother Wavelet in WPT Analysis and Its Influence in Cracked Railway Axles Detection
Machines 2023, 11(4), 493; https://doi.org/10.3390/machines11040493 - 19 Apr 2023
Viewed by 506
Abstract
The detection of cracked railway axles by processing vibratory signals measured during operation is the focus of this study. The rotodynamic theory is applied to this specific purpose but, in practice and for real systems, there is no consensus on applying the results [...] Read more.
The detection of cracked railway axles by processing vibratory signals measured during operation is the focus of this study. The rotodynamic theory is applied to this specific purpose but, in practice and for real systems, there is no consensus on applying the results obtained from theory. Finding reliable patterns that change during operation would have advantages over other currently applied methods, such as non-destructive testing (NDT) techniques, because data between inspections would be obtained during operation. Vibratory signal processing techniques in the time-frequency domain, such as wavelet packet transform (WPT), have proved to be reliable to obtain patterns. The aim of this work is to develop a methodology to select the optimal function associated with the WPT, the mother wavelet (MW), and to find diagnostic patterns for cracked railway axle detection. In previous related works, the Daubechies 6 MW was commonly used for all speed/load conditions and defects. In this work, it was found that the Symlet 9 MW works better, so a comparative study was carried out with both functions, and it was observed that the success rates obtained with Daubechies 6 are improved when using Symlet 9. Specifically, defects above 16.6% of the shaft diameter were reliably detected, with no false alarms. To validate the proposed methodology, experimental vibratory signals of a healthy scaled railway axle were obtained and then the same axle was tested with a transverse crack located close to a section change (where this type of defect typically appears) for nine different crack depths. Full article
(This article belongs to the Special Issue Railway Vehicle Maintenance 4.0)
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Article
Design, Control and Stabilization of a Transformable Wheeled Fire Fighting Robot with a Fire-Extinguishing, Ball-Shooting Turret
Machines 2023, 11(4), 492; https://doi.org/10.3390/machines11040492 - 19 Apr 2023
Viewed by 924
Abstract
In this study, a hybrid wheeled fire extinguisher robot has been created. The robot has a two-degrees-of-freedom (DoF) fire extinguisher gun turret. To control the disruptive effect of mechanical oscillations on the firing system during movement of the robot body, PID and SMC [...] Read more.
In this study, a hybrid wheeled fire extinguisher robot has been created. The robot has a two-degrees-of-freedom (DoF) fire extinguisher gun turret. To control the disruptive effect of mechanical oscillations on the firing system during movement of the robot body, PID and SMC controllers are used. When closed on flat ground, the robot’s five-piece transformable wheel construction allows it to travel swiftly. The wheel mechanism opens on tough terrain, allowing the wheel to assume a star-shaped configuration and enabling the robot to ascend by grasping onto obstructions. The three-dimensional mechanical design of the firefighter robot was designed first, followed by the kinematic model of the turret system and the three-dimensional Simscape model in the Matlab Simmechanic environment. Simulations of throwing fire-extinguishing balls at fire locations positioned at 20 m to 80 m horizontal and 1–30 m vertical distances were carried out on this model for three different scenarios (the robot is stationary, moving at constant speed and rotating around itself). The simulations resulted in a shooting success rate of 85.71% with PID and 95.23% with SMC (for a total of 105 shots). When the mistake rates were investigated, it was discovered that the constructed fire robot was usable in firefighting. Full article
(This article belongs to the Special Issue Design and Control of Mobile Robots)
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Article
Design and Simulation Analysis of Docking Interface of Linked In-Orbit Replacement Module
Machines 2023, 11(4), 491; https://doi.org/10.3390/machines11040491 - 19 Apr 2023
Viewed by 344
Abstract
On-orbit service for spacecraft relies heavily on on-orbit docking with the orbital replacement unit docking interface. Foreign research on the docking interface of the orbit replaceable unit has been in-depth, while the domestic work is still limited. Currently, most design on the docking [...] Read more.
On-orbit service for spacecraft relies heavily on on-orbit docking with the orbital replacement unit docking interface. Foreign research on the docking interface of the orbit replaceable unit has been in-depth, while the domestic work is still limited. Currently, most design on the docking interface relies on the axial feed of the manipulator, which may result in insufficient docking interface mating force under specific conditions. In view of the above problems, it requires a linear plug-in locking interface for the docking of the orbital replaceable unit, and the design scheme of the tapered rod guide and linkage locking parts needs to be determined. Optimization of the linkage locking mechanism is completed by a finite element simulation. The effect of clearance of the taper rod, effective locking points and friction coefficient have been analyzed by means of dynamics modelling during the docking and locking processes. The research also verified the design rationality for the orbital replaceable unit linkage. A processing path and verification for the prototype have been made as well. This work introduces the idea of self-plugging during the orbital docking process. It lays a foundation for the prototype development and control strategy of the orbital replaceable unit. Full article
(This article belongs to the Section Machine Design and Theory)
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Article
Transient and Steady-State Performance Improvement of IM Drives Based on Dual-Torque Model
Machines 2023, 11(4), 490; https://doi.org/10.3390/machines11040490 - 19 Apr 2023
Viewed by 324
Abstract
Transient response performance and steady-state operation performance are the two most important performance indicators of a motor drive system. In order to solve these two problems, this study proposes a new induction motor (IM) model, and then designs a new simplified linearization controller [...] Read more.
Transient response performance and steady-state operation performance are the two most important performance indicators of a motor drive system. In order to solve these two problems, this study proposes a new induction motor (IM) model, and then designs a new simplified linearization controller method. First, the tangential force that determines the transient process of the motor is represented by electromagnetic torque, and the radial force is represented by reactive torque. Then, the dual-torque model of IM is derived, which not only accurately shows the rotating air-gap magnetic field through the amplitude and rotating angular frequency, but also visually demonstrates the physical essence of the transient process of IM. Then, this study proposes a simplified feedback linearization method without the analysis of zero dynamic. In addition, a time-scale hierarchical control system is designed to reduce the ripple caused by the coupling of different time-scale variables. The experimental results show that the steady-state torque ripple of the proposed method is 65% lower than that of RFOC, and the torque response speed is 10% higher than that of DTC. Full article
(This article belongs to the Section Electrical Machines and Drives)
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Article
Simulation and Validation of Cavitating Flow in a Torque Converter with Scale-Resolving Methods
Machines 2023, 11(4), 489; https://doi.org/10.3390/machines11040489 - 19 Apr 2023
Viewed by 598
Abstract
The purpose of this paper is to study the mechanism and improve the prediction accuracy of transient torque converter cavitation flow by the application of scale-resolving simulation (SRS) methods with particular focus on cavitation vortex flow. Firstly, the numerical analysis of the entire [...] Read more.
The purpose of this paper is to study the mechanism and improve the prediction accuracy of transient torque converter cavitation flow by the application of scale-resolving simulation (SRS) methods with particular focus on cavitation vortex flow. Firstly, the numerical analysis of the entire internal flow field of the torque converter was carried out using different turbulence models, and the prediction accuracy of the hydraulic characteristics of the adopted models was analyzed and validated via test data. Secondly, the cavitation and turbulence behavior in the internal flow field were analyzed, and the blade surface pressure according to different turbulence models was compared and validated through test data. Finally, the transient cavitation characteristics of the flow field were studied based on the stress-blended eddy simulation (SBES) model. The prediction accuracy of the cavitation flow field simulation of the torque converter is significantly improved using the SRS model. The maximum error of capacity constant, torque ratio and efficiency are reduced to 3.1%, 2.3%, and 1.3% at stall, respectively. The stator is more prone to cavitation than pump and turbine. The SBES model has the highest prediction accuracy in multiple measurement points, and the maximum deviation can reach 13.32% under stall. Attached cavitation bubbles and periodic shedding cavitation can be found in the stator, and the evolution period is about 0.0036 s, i.e., 279 Hz. The prediction accuracy of different models was compared and analyzed, which has important guiding significance for the high-precision prediction and analysis of fluid machinery. Full article
(This article belongs to the Special Issue 10th Anniversary of Machines—Feature Papers in Turbomachinery)
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Article
An Experimental Investigation and Feasibility Analysis of a Novel Modified Vienna Rectifier for Harmonic Mitigation in an Induction Heating System
Machines 2023, 11(4), 488; https://doi.org/10.3390/machines11040488 - 19 Apr 2023
Viewed by 566
Abstract
This paper presents a novel single-phase modified Vienna rectifier (MVR) for the harmonic mitigation and power factor improvement of an induction heating (IH) system. The latter employs a high-frequency resonant inverter that is responsible for the generation of high-frequency harmonics, which, in turn, [...] Read more.
This paper presents a novel single-phase modified Vienna rectifier (MVR) for the harmonic mitigation and power factor improvement of an induction heating (IH) system. The latter employs a high-frequency resonant inverter that is responsible for the generation of high-frequency harmonics, which, in turn, deteriorates the power quality. This mitigation must be done in accordance with harmonic regulations such as IEEE Std. 519-2014,IEC-555, and EN 61000-3-2, etc. Consequently, an MVR is placed between the power supply and the IH system. The proposed novel MVR topology overcomes the limitations of conventional Vienna rectifiers, such as their unbalanced voltage across output capacitors, high ripple at the output DC bus, and high THD in the supply current, etc. The efficacy of the proposed model has been verified by a series of simulations in PSIM. It is followed by a hardware validation using an Arduino Uno ATmega328 digital controller on a 1.2 kW experimental prototype of the IH system. The simulation and experimental results of the power quality indices comply with the IEEE-519 standards. Full article
(This article belongs to the Section Electrical Machines and Drives)
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Article
Stall Torque Performance Analysis of a YASA Axial Flux Permanent Magnet Synchronous Machine
Machines 2023, 11(4), 487; https://doi.org/10.3390/machines11040487 - 18 Apr 2023
Viewed by 501
Abstract
There is a trend to go towards low gear-ratio or even direct-drive actuators in novel robotic applications in which high-torque density electric motors are required. The Yokeless and Segmented Armature Axial Flux Permanent Magnet Synchronous Machine is therefore considered in this work. In [...] Read more.
There is a trend to go towards low gear-ratio or even direct-drive actuators in novel robotic applications in which high-torque density electric motors are required. The Yokeless and Segmented Armature Axial Flux Permanent Magnet Synchronous Machine is therefore considered in this work. In these applications, the motors should be capable to deliver high torque at standstill for long periods of time. This can cause overheating of the motors due to a concentration of the losses in a single phase; hence, it becomes necessary to derate the motor torque. In this work the influence of the slot/pole combination, the addition of a thermal end-winding interconnection and the equivalent thermal conductivity of the winding body on the torque performance at standstill will be studied both experimentally via temperature measurements on a prototype stator, and via a calibrated 3D thermal Finite Element model. It was found that both a good choice of the slot/pole combination and the addition of a thermal end-winding interconnection have a significant influence on the torque performance at standstill, and allow up to 8% increase in torque at standstill in comparison to a reference design. Full article
(This article belongs to the Topic Advanced Electrical Machines and Drives Technologies)
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Article
An Integrated Co-Design Optimization Toolchain Applied to a Conjugate Cam-Follower Drivetrain System
Machines 2023, 11(4), 486; https://doi.org/10.3390/machines11040486 - 18 Apr 2023
Cited by 1 | Viewed by 572
Abstract
Due to ever increasing performance requirements, model-based optimization and control strategies are increasingly being adopted by machine builders and automotive companies. However, this demands an increase in modelling effort and a growing knowledge of optimization techniques, as a sufficient level of detail is [...] Read more.
Due to ever increasing performance requirements, model-based optimization and control strategies are increasingly being adopted by machine builders and automotive companies. However, this demands an increase in modelling effort and a growing knowledge of optimization techniques, as a sufficient level of detail is required in order to evaluate certain performance characteristics. Modelling tools such as MATLAB Simscape have been created to reduce this modelling effort, allowing for greater model complexity and fidelity. Unfortunately, this tool cannot be used with high-performance gradient-based optimization algorithms due to obfuscation of the underlying model equations. In this work, an optimization toolchain is presented that efficiently interfaces with MATLAB Simscape to reduce user effort and the necessary skill and computation time required for the optimization of high-fidelity drivetrain models. The toolchain is illustrated on an industrially relevant conjugate cam-follower system, which is modelled in the Simscape environment and validated with respect to a higher-fidelity modeling technique, namely, the finite element method (FEM). Full article
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Article
Dynamic Thermal Neutron Radiography for Filling Process Analysis and CFD Model Validation of Visco-Dampers
Machines 2023, 11(4), 485; https://doi.org/10.3390/machines11040485 - 18 Apr 2023
Viewed by 518
Abstract
The visco-damper is a crucial engine accessory from an operation- as well as vehicle-safety point of view. The service life of this damping product is determined by the degradation of the silicone oil applied to it. The thermal and mechanical degradation of the [...] Read more.
The visco-damper is a crucial engine accessory from an operation- as well as vehicle-safety point of view. The service life of this damping product is determined by the degradation of the silicone oil applied to it. The thermal and mechanical degradation of the oil starts not at the first operation of the damper, but at the manufacturing stage when the oil is filled into the damper’s gap at high pressure. Finite volume method-based computational fluid dynamic calculations provide an opportunity to optimize the filling process by minimizing the oil degradation. A three-dimensional, transient, non-Newtonian, multiphase, coupled fluid dynamic and heat transfer simulation model was developed to analyse the filling process and to investigate the effect of the slide bearing’s cut-off position on the filling process. Dynamic thermal neutron radiography was employed to visualize the filling of a test damper for model validation from viscous and fluid dynamic aspects. Distinct properties of neutrons compared to the more commonly applied X-rays were proven to be an effective tool for real-time monitoring of the silicone oil’s front propagation in the damper’s gap and for quantifying the characteristics of the filling process. Visual matching and comparison of propagation times and oil front velocity profiles were used to validate the simulation results. Full article
(This article belongs to the Section Vehicle Engineering)
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Article
Influence of Profile Geometry on Frictional Energy Dissipation in a Dry, Compliant Steel-on-Steel Fretting Contact: Macroscopic Modeling and Experiment
Machines 2023, 11(4), 484; https://doi.org/10.3390/machines11040484 - 18 Apr 2023
Viewed by 440
Abstract
Dry, frictional steel-on-steel contacts under small-scale oscillations are considered experimentally and theoretically. As indenting bodies, spheres, and truncated spheres are used to retrace the transition from smooth to sharp contact profile geometries. The experimental apparatus is built as a compliant setup, with the [...] Read more.
Dry, frictional steel-on-steel contacts under small-scale oscillations are considered experimentally and theoretically. As indenting bodies, spheres, and truncated spheres are used to retrace the transition from smooth to sharp contact profile geometries. The experimental apparatus is built as a compliant setup, with the characteristic macroscopic values of stiffness being comparable to or smaller than the contact stiffness of the fretting contact. A hybrid macroscopic–contact model is formulated to predict the time development of the macroscopic contact quantities (forces and global relative surface displacements), which are measured in the experiments. The model is well able to predict the macroscopic behavior and, accordingly, the frictional hysteretic losses observed in the experiment. The change of the indenter profile from spherical to truncated spherical “pushes” the fretting contact towards the sliding regime if the nominal normal force and tangential displacement oscillation amplitude are kept constant. The transition of the hysteretic behavior, depending on the profile geometry from the perfectly spherical to the sharp flat-punch profile, occurs for the truncated spherical indenter within a small margin of the radius of its flat face. Already for a flat face radius which is roughly equal to the contact radius for the spherical case, the macroscopic hysteretic behavior cannot be distinguished from a flat punch contact with the same radius. The compliance of the apparatus (i.e., the macrosystem) can have a large influence on the energy dissipation and the fretting regime. Below a critical value for the stiffness, the fretting contact exhibits a sharp transition to the “sticking” regime. However, if the apparatus stiffness is large enough, the hysteretic behavior can be controlled by changing the profile geometry. Full article
(This article belongs to the Special Issue Dry Friction: Theory, Analysis and Applications)
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Article
The Influence of a Blade-Guiding Fin on the Pneumatic Performance of an Axial-Flow Cooling Fan
Machines 2023, 11(4), 483; https://doi.org/10.3390/machines11040483 - 18 Apr 2023
Viewed by 450
Abstract
An axial-flow cooling fan was taken as the research object in this paper, and a certain number of simulation models with different blade-guiding fin shapes were established. The methods of computational fluid dynamics (CFD), circumferential vorticity (CV) analysis and the response surface method [...] Read more.
An axial-flow cooling fan was taken as the research object in this paper, and a certain number of simulation models with different blade-guiding fin shapes were established. The methods of computational fluid dynamics (CFD), circumferential vorticity (CV) analysis and the response surface method (RSM) based on the design of experiments (DOE) method were all employed. The main external flow characteristics of the cooling fan, the blade surface pressure distribution, the static pressure efficiency and the fan power were obtained and compared. The relationships between the pneumatic performance and the fin shape parameters were subsequently investigated by the DOE method. The results obtained in this paper showed that a change in the fin height had a great influence on the pneumatic performance, while changes in its thickness had less of an influence. For the cooling fan studied in this paper, by adding reasonable structure-guiding fins onto the cooling fan blade, the static pressure efficiency was increased by a maximum of 7.6%. The research results have a good guiding significance regarding the srtructure design and optimization of axial cooling fans. Full article
(This article belongs to the Section Turbomachinery)
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Article
Evaluation of Different Fault Diagnosis Methods and Their Applications in Vehicle Systems
Machines 2023, 11(4), 482; https://doi.org/10.3390/machines11040482 - 17 Apr 2023
Viewed by 757
Abstract
A high level of automation in vehicles is accompanied by a variety of sensors and actuators, whose malfunctions must be dealt with caution because they might cause serious driving safety hazards. Therefore, a robust and highly accurate fault detection and diagnosis system to [...] Read more.
A high level of automation in vehicles is accompanied by a variety of sensors and actuators, whose malfunctions must be dealt with caution because they might cause serious driving safety hazards. Therefore, a robust and highly accurate fault detection and diagnosis system to monitor the operational states of vehicle systems is an indispensable prerequisite. In the area of fault diagnosis, numerous techniques have been studied, and each one has pros and cons. Selecting the best approach based on the requirements or usage scenarios will save much needless work. In this article, the authors examine some of the most common fault diagnosis methods for their applicability to automated vehicle systems: the traditional binary logic method, the fuzzy logic method, the fuzzy neural method, and two neural network methods (the feedforward neural network and the convolutional neural network). For each approach, the diagnosis algorithms for vehicle systems were modeled differently. The analysis of the detection capabilities and the suitable application scenarios of each fault diagnosis approach for vehicle systems, as well as recommendations for selecting different methods for various diagnosis needs, are also provided. In the future, this can serve as an effective guide for the selection of a suitable fault diagnosis approach based on the application scenarios for vehicle systems. Full article
(This article belongs to the Special Issue Advances in Fault Diagnosis and Anomaly Detection)
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Review
Intelligent Fault Diagnosis of an Aircraft Fuel System Using Machine Learning—A Literature Review
Machines 2023, 11(4), 481; https://doi.org/10.3390/machines11040481 - 16 Apr 2023
Viewed by 996
Abstract
The fuel system, which aims to provide sufficient fuel to the engine to maintain thrust and power, is one of the most critical systems in the aircraft. However, possible degradation modes, such as leakage and blockage, can lead to component failure, affect performance, [...] Read more.
The fuel system, which aims to provide sufficient fuel to the engine to maintain thrust and power, is one of the most critical systems in the aircraft. However, possible degradation modes, such as leakage and blockage, can lead to component failure, affect performance, and even cause serious accidents. As an advanced maintenance strategy, Condition Based Maintenance (CBM) can provide effective coverage, by combining state-of-the-art sensors with data acquisition and analysis techniques to guide maintenance before the asset’s degradation becomes serious. Artificial Intelligence (AI), particularly machine learning (ML), has proved effective in supporting CBM, for analyzing data and generating predictions regarding the asset’s health condition, thus influencing maintenance plans. However, from an engineering perspective, the output of ML algorithms, usually in the form of data-driven neural networks, has come into question in practice, as it can be non-intuitive and lacks the ability to provide unambiguous engineering signals to maintainers, making it difficult to trust. Engineers are interested in a deterministic decision-making process and how it is being revealed; algorithms should be able to certify and convince engineers to approve recommended actions. Explainable AI (XAI) has emerged as a potential solution, providing some of the logic on how the output is derived from the input given, which may help users understand the diagnostic result of the algorithm. In order to inspire and advise data scientists and engineers who are about to develop and use AI approaches in fuel systems, this paper explores the literature of experiment, simulation, and AI-based diagnostics for the fuel system to make an informed statement as to the progress that has been made in intelligent fault diagnostics for fuel systems, emphasizing the necessity of giving unambiguous engineering signals to maintainers, as well as highlighting potential areas for future research. Full article
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Article
Methodology for Tool Wear Detection in CNC Machines Based on Fusion Flux Current of Motor and Image Workpieces
Machines 2023, 11(4), 480; https://doi.org/10.3390/machines11040480 - 14 Apr 2023
Viewed by 831
Abstract
In the manufacturing industry, computer numerical control (CNC) machine tools are of great importance since the processes in which they are used allow the creation of elements used in multiple sectors. Likewise, the condition of the cutting tools used is paramount due to [...] Read more.
In the manufacturing industry, computer numerical control (CNC) machine tools are of great importance since the processes in which they are used allow the creation of elements used in multiple sectors. Likewise, the condition of the cutting tools used is paramount due to the effect they have on the process and the quality of the supplies produced. For decades, methodologies have been developed that employ various signals and sensors for wear detection, prediction and monitoring; however, this field is constantly evolving, with new technologies and methods that have allowed the development of non-invasive, efficient and robust systems. This paper proposes the use of magnetic stray flux and motor current signals from a CNC lathe and the analysis of images of machined parts for wear detection using online and offline information under the variation in cutting speed and tool feed rate. The information obtained is processed through statistical and non-statistical indicators and dimensionally reduced by linear discriminant analysis (LDA) and a feed-forward neural network (FFNN) for wear classification. The results obtained show a good performance in wear detection using the individual signals, achieving efficiencies of 77.5%, 73% and 89.78% for the analysis of images, current and stray flux signals, respectively, under the variation in cutting speed, and 76.34%, 73% and 63.12% for the analysis of images, current and stray flux signals, respectively, under the variation of feed rate. Significant improvements were observed when the signals are fused, increasing the efficiency up to 95% for the cutting speed variations and 82.84% for the feed rate variations, achieving a system that allows detecting the wear present in the tools according to the needs of the process (online/offline) under different machining parameters. Full article
(This article belongs to the Section Advanced Manufacturing)
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Article
Reinforcement Learning-Based Dynamic Zone Placement Variable Speed Limit Control for Mixed Traffic Flows Using Speed Transition Matrices for State Estimation
Machines 2023, 11(4), 479; https://doi.org/10.3390/machines11040479 - 14 Apr 2023
Viewed by 571
Abstract
Current transport infrastructure and traffic management systems are overburdened due to the increasing demand for road capacity, which often leads to congestion. Building more infrastructure is not always a practical strategy to increase road capacity. Therefore, services from Intelligent Transportation Systems (ITSs) are [...] Read more.
Current transport infrastructure and traffic management systems are overburdened due to the increasing demand for road capacity, which often leads to congestion. Building more infrastructure is not always a practical strategy to increase road capacity. Therefore, services from Intelligent Transportation Systems (ITSs) are commonly applied to increase the level of service. The growth of connected and autonomous vehicles (CAVs) brings new opportunities to the traffic management system. One of those approaches is Variable Speed Limit (VSL) control, and in this paper a VSL based on Q-Learning (QL) using CAVs as mobile sensors and actuators in combination with Speed Transition Matrices (STMs) for state estimation is developed and examined. The proposed Dynamic STM-QL-VSL (STM-QL-DVSL) algorithm was evaluated in seven traffic scenarios with CAV penetration rates ranging from 10% to 100%. The proposed STM-QL-DVSL algorithm utilizes two sets of actions that include dynamic speed limit zone positions and computed speed limits. The proposed algorithm was compared to no control, rule-based VSL, and two STM-QL-VSL configurations with fixed VSL zones. The developed STM-QL-DVSL outperformed all other control strategies and improved measured macroscopic traffic parameters like Total Time Spent (TTS) and Mean Travel Time (MTT) by learning the control policy for each simulated scenario. Full article
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Article
An Inverse Kinematics Approach for the Analysis and Active Control of a Four-UPR Motion-Compensated Platform for UAV–ASV Cooperation
Machines 2023, 11(4), 478; https://doi.org/10.3390/machines11040478 - 14 Apr 2023
Viewed by 627
Abstract
In the present day, unmanned aerial vehicle (UAV) technology is being used for a multitude of inspection operations, including those in offshore structures such as wind-farms. Due to the distance of these structures to the coast, drones need to be carried to these [...] Read more.
In the present day, unmanned aerial vehicle (UAV) technology is being used for a multitude of inspection operations, including those in offshore structures such as wind-farms. Due to the distance of these structures to the coast, drones need to be carried to these structures via ship. To achieve a completely autonomous operation, the UAV can greatly benefit from an autonomous surface vehicle (ASV) to transport the UAV to the operation location and coordinate a successful landing between the two. This work presents the concept of a four-link parallel platform to perform wave-motion synchronization to facilitate UAV landings. The parallel platform consists of two base floaters connected with rigid rods, linked by linear actuators to a top mobile platform for the landing of a UAV. Using an inverse kinematics approach, a study of the position of the cylinders for greater range of motion and a workspace analysis is achieved. The platform makes use of a feedback controller to reduce the total motion of the landing platform. Using the robotic operating system (ROS) and Gazebo to emulate wave motions and represent the physical model and actuator system, the platform control system was successfully validated. Full article
(This article belongs to the Special Issue Advances and Applications in Unmanned Aerial Vehicles)
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Editorial
Editorial
Machines 2023, 11(4), 477; https://doi.org/10.3390/machines11040477 - 14 Apr 2023
Viewed by 398
Abstract
In recent decades, the research on autonomous driving technologies has enabled the automotive industry to introduce vehicles supported by Advanced Driver-Assistance Systems (ADAS) to the market [...] Full article
Article
A Continuous Production Apparatus for a Frame-Type Melt-Blown Filter Cartridge with Various Properties and Geometry
Machines 2023, 11(4), 476; https://doi.org/10.3390/machines11040476 - 13 Apr 2023
Viewed by 535
Abstract
Polypropylene (PP) melt-blown (MB) filter cartridges are widely used in many fields requiring water purification, such as households, the food industry, industrial processes, and recycled water filtration. While the demand for filters has gradually increased, the environmental requirements and conditions have become severe. [...] Read more.
Polypropylene (PP) melt-blown (MB) filter cartridges are widely used in many fields requiring water purification, such as households, the food industry, industrial processes, and recycled water filtration. While the demand for filters has gradually increased, the environmental requirements and conditions have become severe. The filters are easily deformed from higher liquid pressure during operation and setup and need to be replaced frequently. With the lifetime of filters shortened, manpower increases to replace filters. Hence, the inner structure of a PP melt-blown filter cartridge is supported by a frame structure to resist higher liquid pressure for enhancing filtration efficiency and lifetime. The filter, known as a “frame-type melt-blown filter cartridge”, does not affect the user’s application environment and equipment. This article focuses on developing continuous production equipment for frame-type melt-blown filter cartridges. The core technology of the equipment is the mechanism design for conveying frame tubes integrated with the MB process. The PP fiber is simultaneously melted and blown on the frame tube, and the frame tube needs to be pushed forward while rotating. This mechanism can independently control the fiber’s rotational speed and push speed. The rotational speed affects the surface density, fiber diameter, and porosity of the melt-blown filter cartridge, and the push speed affects the core diameter and weight of the melt-blown filter cartridge. In addition, there is a frame tube feeding device at the input end of the conveying equipment for continuously carrying the frame tube. Then, the finally formed melt-blown filter cartridges enter the cutting machine to trim a certain length to complete a frame-type melt-blown filter cartridge. The complexity of the operation is simplified by a human–machine interactive interface. A programmable logic controller (PLC) and a LabVIEW human–machine interactive interface are used to dominate the equipment. The Modbus communication protocol is adopted for connecting and communicating between PLC and LabVIEW. The interface can integrate and analyze the process data, including overall equipment effectiveness (OEE), total effective equipment performance (TEEP), loading time, utilization, performance, and yield. The entire production process of the frame-type melt-blown filter cartridge is optimized, and the traditional output of 1000 per day is upgraded to 1300. Overall, the processing speed is increased by up to 30%. Full article
(This article belongs to the Section Industrial Systems)
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Article
Deep PCA-Based Incipient Fault Diagnosis and Diagnosability Analysis of High-Speed Railway Traction System via FNR Enhancement
Machines 2023, 11(4), 475; https://doi.org/10.3390/machines11040475 - 13 Apr 2023
Cited by 1 | Viewed by 640
Abstract
In recent years, the data-driven based FDD (Fault Detection and Diagnosis) of high-speed train electric traction systems has made rapid progress, as the safe operation of traction system is closely related to the reliability and stability of high-speed trains. The internal complexity and [...] Read more.
In recent years, the data-driven based FDD (Fault Detection and Diagnosis) of high-speed train electric traction systems has made rapid progress, as the safe operation of traction system is closely related to the reliability and stability of high-speed trains. The internal complexity and external complexity of the environment mean that fault diagnosis of high-speed train traction system faces great challenges. In this paper, a wavelet transform-based FNR (Fault to Noise Ratio) enhancement is realised to highlight incipient fault information and a Deep PCA (Principal Component Analysis)-based diagnosability analysis framework is proposed. First, a scheme for FNR enhancement-based fault data preprocessing with selection of the intelligent decomposition levels and optimal noise threshold is proposed. Second, fault information enhancement technology based on continuous wavelet transform is proposed from the perspective of energy. Further, a Deep-PCA based incipient fault detectability and isolatability analysis are provided via geometric descriptions. Finally, experiments on the TDCS-FIB (Traction Drive Control System–Fault Injection Benchmark) platform fully demonstrate the effectiveness of the method proposed in this paper. Full article
(This article belongs to the Special Issue Advanced Data Analytics in Intelligent Industry: Theory and Practice)
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Article
A Simple Semi-Analytical Method for Solving Axisymmetric Contact Problems Involving Bonded and Unbonded Layers of Arbitrary Thickness
Machines 2023, 11(4), 474; https://doi.org/10.3390/machines11040474 - 13 Apr 2023
Viewed by 644
Abstract
In the present work, a recently extended version of the method of dimensionality reduction (MDR) for layered elastic media is applied for the first time using a semi-analytical approach. It is based on a priori knowledge of the cylindrical flat punch solution which [...] Read more.
In the present work, a recently extended version of the method of dimensionality reduction (MDR) for layered elastic media is applied for the first time using a semi-analytical approach. It is based on a priori knowledge of the cylindrical flat punch solution which is determined numerically using the boundary element method (BEM). We consider arbitrary indenters of revolution producing a circular area of contact with bonded and unbonded layers of arbitrary thickness. The proposed method reduces the contact solution to the numerically efficient evaluation of simple one-dimensional integrals. We further show that the solution of JKR-adhesive contacts with layers and contacts with linear-viscoelastic layers is straightforward using the well-known MDR formalisms. A specific focus has been devoted to study the thickness effect in different application examples. Comparisons with the literature and finite element simulations show very good agreement with the proposed method. Full article
(This article belongs to the Special Issue Dry Friction: Theory, Analysis and Applications)
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Article
Influence of Laser Surface Texture on the Anti-Friction Properties of 304 Stainless Steel
Machines 2023, 11(4), 473; https://doi.org/10.3390/machines11040473 - 12 Apr 2023
Viewed by 435
Abstract
To enhance the anti-friction properties of 304 stainless steel, friction experiments were conducted on it after laser surface texturing. The influences of laser scanning speed, repetition frequency, processing times, laser beam line spacing, and lattice spacing on the friction properties of 304 stainless [...] Read more.
To enhance the anti-friction properties of 304 stainless steel, friction experiments were conducted on it after laser surface texturing. The influences of laser scanning speed, repetition frequency, processing times, laser beam line spacing, and lattice spacing on the friction properties of 304 stainless steel were investigated by contrast tests under annular filling mode. The results revealed that laser texturing improved the anti-friction properties of 304 stainless steel. The friction coefficient of the sample surface decreased first and then increased with the increase in scanning speed, repetition frequency, processing times, laser beam line spacing, and lattice spacing. Based on this, process optimization found that a stainless steel surface with good anti-friction properties could be obtained when the laser power was 0.3 W, the repetition frequency was 50 kHz, the scanning speed was 80 mm/s, the laser beam line spacing was 1 μm, the lattice spacing was 200 μm, and the number of processing times was two. Finally, scanning electron microscope (SEM) characterization of wear morphology on the sample surface showed that the laser textured surface could collect debris during effective friction, which reduced the occurrence of abrasive and adhesive wear. Meanwhile, the actual contact area of the friction pair was effectively reduced, thereby reducing friction force and wear. This study provided experimental data and a theoretical basis for improving the friction properties of the 304 stainless steel surface and laid the foundation for its reliable use under friction and wear conditions. Full article
(This article belongs to the Topic Advanced Manufacturing and Surface Technology)
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