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Machines, Volume 10, Issue 10 (October 2022) – 142 articles

Cover Story (view full-size image): Due to the harsh operating conditions of industrial hose pumps, accurate and efficient numerical simulations of the hose would be significant but tough. Therefore, a finite element (FE) model simulating a non-braided fabric composite rubber hose is established. Counter force and profile deformation tests of the hose show a good accuracy with the simulation results. Based on the FE model, dependencies of counter force, maximum strain and stress and the contact area of the hose on the pressing displacement are revealed, which help to decide the pressing displacement numerically. The predicted pressing displacements to seal off the hose under different pressures are also given. The proposed methodology of hose pump modeling is helpful for the fully virtual simulation and design of industrial hose pumps. View this paper
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18 pages, 10346 KiB  
Article
Lattice Structure Design Method Aimed at Energy Absorption Performance Based on Bionic Design
by Gang He, Hu Yang, Tao Chen, Yuan Ning, Huatao Zou and Feng Zhu
Machines 2022, 10(10), 965; https://doi.org/10.3390/machines10100965 - 21 Oct 2022
Cited by 5 | Viewed by 2645
Abstract
To obtain the lattice structure with excellent energy absorption performance, the structure of loofah inner fiber is studied to develop bionic design of lattice structure by experiment and simulation analysis method. From the compression experiment about the four bionic multi-cell lattice structures (bio-45, [...] Read more.
To obtain the lattice structure with excellent energy absorption performance, the structure of loofah inner fiber is studied to develop bionic design of lattice structure by experiment and simulation analysis method. From the compression experiment about the four bionic multi-cell lattice structures (bio-45, bio-60, bio-75, and bio-90) and VC lattice structures, we found that all are made of PLA and fabricated by the fused deposition modeling (FDM) 3D printer. The comprehensive performance of bio-90 lattice structure is the best in the performance of the specific volume energy absorption (SEAv), the effective energy absorption (EA), and the specific energy absorption (SEA). Based on the experimental result, the energy absorption performance of bio-90 lattice structure is then studied by the simulation analysis of influence on multiple parameters, such as the number of cells, the relative density, the impact velocity, and the material. The results can provide a reference for the design of highly efficient energy absorption structures. Full article
(This article belongs to the Special Issue Bio-Inspired Smart Machines: Structure, Mechanisms and Applications)
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16 pages, 6236 KiB  
Article
Electromagnetic Characteristics Analysis and Structure Optimization of High-Speed Fuel Solenoid Valves
by Liu Yang, Tianxiong Gao, Xinming Du, Fugang Zhai, Chang Lu and Xiangdong Kong
Machines 2022, 10(10), 964; https://doi.org/10.3390/machines10100964 - 21 Oct 2022
Cited by 6 | Viewed by 2475
Abstract
High-speed fuel solenoid valves (HFSVs) are the key control elements of aero-engine vane regulators. A strong electromagnetic force generated from the HFSVs is essential to achieve precise control over timing and quantification for fuel supply. In this paper, the Taguchi method is adopted [...] Read more.
High-speed fuel solenoid valves (HFSVs) are the key control elements of aero-engine vane regulators. A strong electromagnetic force generated from the HFSVs is essential to achieve precise control over timing and quantification for fuel supply. In this paper, the Taguchi method is adopted to improve the HFSV’s static electromagnetic characteristics. First, an electromagnetic model of the HFSV was established and experiments were conducted to modify and validate the model. Effects of key structural factors on the static electromagnetic characteristics of the HFSV are then investigated via the finite element method (FEM). Based on the optimization, an HFSV prototype is finally manufactured and tested. The experiment results are in good agreement with those of the simulations. It provides a significant guideline for the manufacturing process of such HFSVs. Full article
(This article belongs to the Special Issue Advanced Control of Electro-Hydraulic Systems in Industrial Area)
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17 pages, 5362 KiB  
Article
Motion Law and Mechanical Properties of PIGs When Passing through a Pipe Bend
by Shengtao Chen, Lei Xia, Xiaolu Wang, Kai Teng, Yibo Zhang, Meiyu Zhang and Yongjun Gong
Machines 2022, 10(10), 963; https://doi.org/10.3390/machines10100963 - 21 Oct 2022
Cited by 2 | Viewed by 4753
Abstract
Pipeline inspection gauges (PIGs), as a kind of pipeline robot, are very efficient tools for cleaning and inspecting pipelines. However, the occurrence of obstructions in PIGs has always been a problem. The main cause of the PIG clogging pipeline problem is the reduced [...] Read more.
Pipeline inspection gauges (PIGs), as a kind of pipeline robot, are very efficient tools for cleaning and inspecting pipelines. However, the occurrence of obstructions in PIGs has always been a problem. The main cause of the PIG clogging pipeline problem is the reduced pressure differential between the front and rear due to damage to the cup. In this paper, a rigid-flexible coupled multibody dynamic motion system is established by importing flexible bodies. The stress and contact force generated by the elastic deformation of the cup in the pipe are analyzed. Moreover, the spacing ratio of PIG cups and the number of cups were changed, the number of cabin sections was increased, the bending of PIGs of different sizes and specifications was studied, and the influence of the cross-universal joint on the bending of PIGs, as well as the force between the cups and the core tube, was analyzed. Through the design and construction of the corresponding experimental equipment, the influence of the change in the number of leather cups on cornering is studied. Full article
(This article belongs to the Special Issue Mobile Robotics: Mathematics, Models and Methods)
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15 pages, 2977 KiB  
Article
Highly Stable Switchable Emissions of an Erbium-Doped Fiber Ring Laser Using Cascaded MZIs Based on CHCF
by Luis A. Herrera-Piad, Sigifredo Marrujo-García, Iván Hernández-Romano, Daniel A. May-Arrioja, Vladimir P. Minkovich and Miguel Torres-Cisneros
Machines 2022, 10(10), 962; https://doi.org/10.3390/machines10100962 - 21 Oct 2022
Cited by 1 | Viewed by 1332
Abstract
A stable, single, and dual-wavelength erbium-doped fiber laser (EDFL), based on two Mach–Zehnder interferometers (MZIs), arranged in a cascade configuration, was proposed for experimental purposes. Both MZIs were assembled by splicing a capillary hollow-core fiber (CHCF) section between two multimode fibers (MMFs) segments. [...] Read more.
A stable, single, and dual-wavelength erbium-doped fiber laser (EDFL), based on two Mach–Zehnder interferometers (MZIs), arranged in a cascade configuration, was proposed for experimental purposes. Both MZIs were assembled by splicing a capillary hollow-core fiber (CHCF) section between two multimode fibers (MMFs) segments. The novelty of this single and dual-wavelength EDFL is that the switchable operation of the laser is achieved by thermally tuning the interference pattern of one MZI and not by adjusting the polarization state inside the fiber ring cavity. The maximum measured value of SNR was 58.9 dB for the single and dual-wavelength laser emissions. Moreover, the stable output power exhibited by this EDFL, in terms of minimal power and wavelength fluctuations, at 0.05 dB and 10 pm, was detected during the single and dual-wavelength operation. It is worth noticing that switching is achieved at exact wavelength locations with a separation of 1.8 nm and not randomly, as reported by other works. These features make this switchable EDFL an appealing candidate for application in optical fiber communication systems and fiber sensing. Full article
(This article belongs to the Special Issue Advances in New Laser Devices and Technologies)
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15 pages, 18955 KiB  
Article
Comparison between Genetic Programming and Dynamic Models for Compact Electrohydraulic Actuators
by Hamid Bamshad, Seongwon Jang, Hyemi Jeong, Jaesung Lee and Hyunseok Yang
Machines 2022, 10(10), 961; https://doi.org/10.3390/machines10100961 - 21 Oct 2022
Viewed by 1614
Abstract
A compact electrohydraulic actuator (C-EHA) is an innovative hydraulic system with a wide range of applications, particularly in automation, robotics, and aerospace. The actuator provides the benefits of hydraulics without the expense and space requirements of full-sized hydraulic systems and in a much [...] Read more.
A compact electrohydraulic actuator (C-EHA) is an innovative hydraulic system with a wide range of applications, particularly in automation, robotics, and aerospace. The actuator provides the benefits of hydraulics without the expense and space requirements of full-sized hydraulic systems and in a much cleaner manner. However, this actuator is associated with some disadvantages, such as a high level of nonlinearity, uncertainty, and a lack of studies. The development of a robust controller requires a thorough understanding of the system behavior as well as an accurate dynamic model of the system; however, finding an accurate dynamic model of a system is not always straightforward, and it is considered a significant challenge for engineers, particularly for a C-EHA because the critical parameters inside cannot be accessed. Our research aims to evaluate and confirm the ability of genetic programming (GP) to model a nonlinear system for a C-EHA. In our paper, we present and develop a GP model for the C-EHA system. Furthermore, our study presents a dynamic model of the system for comparison with the GP model. As a result, by using this actuator in the 1-DOF arm system and conducting experiments, we confirmed that the GP model has a better performance with less positional error compared with the proposed dynamic model. The model can be used to conduct further studies, such as designing controllers or system simulations. Full article
(This article belongs to the Special Issue Advanced Control of Electro-Hydraulic Systems in Industrial Area)
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31 pages, 4118 KiB  
Review
Intelligent Mechatronics in the Measurement, Identification, and Control of Water Level Systems: A Review and Experiment
by Paweł Olejnik and Jan Awrejcewicz
Machines 2022, 10(10), 960; https://doi.org/10.3390/machines10100960 - 20 Oct 2022
Cited by 2 | Viewed by 3720
Abstract
In this paper, a unique overview of intelligent machines and mathematical methods designed and developed to measure and to control the water level in industrial or laboratory setups of coupled and cascaded configurations of tanks is made. A systematized and concise overview is [...] Read more.
In this paper, a unique overview of intelligent machines and mathematical methods designed and developed to measure and to control the water level in industrial or laboratory setups of coupled and cascaded configurations of tanks is made. A systematized and concise overview is made of the mechatronic systems used in the measurement, identification, and control of the water level enumerates, the software used in the associated scientific research, modern techniques and sensors, and mathematical models, as well as analysis and control strategies. The broad overview of applications of the last decade is finalized by a proposition of a control system that is based on a parameter estimation of a new experimental setup, an integral dynamic model of the system, a modern mechatronic machine such as the Watson-Marlow peristaltic pump, the Anderson Negele sensor of level, the NI cRIO-9074 controller, and LabVIEW virtual instrumentation. The results of real experimental tests, exploiting a hybrid proportional control, being improved by a numerically predicted water level, are obtained using a few tools, i.e., the static characteristics, the classical step response, and a new pyramid-shaped step function of a discontinuous path-following reference input, being introduced to evaluate the effectiveness and robustness of the regulation of the level height. Full article
(This article belongs to the Special Issue Feature Review Papers on Automation Systems)
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17 pages, 9299 KiB  
Article
Analysis of Ball Check Valves with Conical and Spherical Seat Designs from Common-Rail Pumps
by Narcis-Daniel Petrea, Razvan-Constantin Iordache and Carmen Bujoreanu
Machines 2022, 10(10), 959; https://doi.org/10.3390/machines10100959 - 20 Oct 2022
Cited by 1 | Viewed by 3634
Abstract
Common-rail fuel injection systems are still a good option for equipping new car models. The technology is well known, systems of this type are reliable and can be used on a wide variety of diesel and petrol engines. However, there is still room [...] Read more.
Common-rail fuel injection systems are still a good option for equipping new car models. The technology is well known, systems of this type are reliable and can be used on a wide variety of diesel and petrol engines. However, there is still room for improvement. The ball check valve, which is part of the common-rail pump, is designed to open and allow the compressed fluid to be sent to the high-pressure accumulator and close to not allow fuel to return to the compression chamber. The valves’ design directly influences the volumetric efficiency of the outlet flow and the robustness against high pressures that lead to low performance and short service life of the fuel injection systems. This paper aims to compare two ball check valves with conical and spherical seat designs. The analysis is based on theoretical calculations and CFD simulations, which will give more confidence in the results. Considering the comparative analysis results, the ball check valve with a spherical seat shows better flow dynamics than the ball check valve with a conical seat. In addition to the improved flow dynamics, the ball check valve with spherical seat seems to have a uniformly distributed fluid pressure inside the valve. In contrast, the conical seat ball check valve has high local fluid pressures, leading to fatigue. Full article
(This article belongs to the Special Issue Design and Manufacture of Advanced Machines)
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15 pages, 4424 KiB  
Article
Assessing the Performance of Design Variations of a Thermoacoustic Stirling Engine Combining Laboratory Tests and Model Results
by Carmen Iniesta, José Luis Olazagoitia, Jordi Vinolas and Jaime Gros
Machines 2022, 10(10), 958; https://doi.org/10.3390/machines10100958 - 20 Oct 2022
Viewed by 1780
Abstract
The equations governing energy conversion in traveling wave thermoacoustic machines are affected by their multiphysics nature. Their theoretical study is complicated and, in order to obtain real results, it is necessary to resort to prototypes and experimental tests. This work presents the theoretical–experimental [...] Read more.
The equations governing energy conversion in traveling wave thermoacoustic machines are affected by their multiphysics nature. Their theoretical study is complicated and, in order to obtain real results, it is necessary to resort to prototypes and experimental tests. This work presents the theoretical–experimental study of a thermoacoustic Stirling engine in which, by altering some of its critical parts and analysing the experimental result, it is possible to improve its performance. The methodology used is based on the study and modelling of the active and reactive acoustic power flow for the improvement of the output power of the thermoacoustic engine. The work and analysis are illustrated through the instrumentation of a thermoacoustic Stirling engine with three different feedbacks. The present work presents the experimental results obtained in all cases, including their parameters, experimental data and analysis. The results are compared with the virtual computational models, allowing us to quantify the theoretical/experimental correlation and the performance improvement obtained that allows us to significantly increase the energy provided by the thermoacoustic machine. In conclusion, it is shown that the proposed methodology is a useful design tool that allows using a simplified and practical approach in the study of the power flow of thermoacoustic machines. Full article
(This article belongs to the Special Issue New Advances in Energy Harvesters)
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23 pages, 8614 KiB  
Article
Multimodal Interface for Human–Robot Collaboration
by Samu Rautiainen, Matteo Pantano, Konstantinos Traganos, Seyedamir Ahmadi, José Saenz, Wael M. Mohammed and Jose L. Martinez Lastra
Machines 2022, 10(10), 957; https://doi.org/10.3390/machines10100957 - 20 Oct 2022
Cited by 7 | Viewed by 2931
Abstract
Human–robot collaboration (HRC) is one of the key aspects of Industry 4.0 (I4.0) and requires intuitive modalities for humans to communicate seamlessly with robots, such as speech, touch, or bodily gestures. However, utilizing these modalities is usually not enough to ensure a good [...] Read more.
Human–robot collaboration (HRC) is one of the key aspects of Industry 4.0 (I4.0) and requires intuitive modalities for humans to communicate seamlessly with robots, such as speech, touch, or bodily gestures. However, utilizing these modalities is usually not enough to ensure a good user experience and a consideration of the human factors. Therefore, this paper presents a software component, Multi-Modal Offline and Online Programming (M2O2P), which considers such characteristics and establishes a communication channel with a robot with predefined yet configurable hand gestures. The solution was evaluated within a smart factory use case in the Smart Human Oriented Platform for Connected Factories (SHOP4CF) EU project. The evaluation focused on the effects of the gesture personalization on the perceived workload of the users using NASA-TLX and the usability of the component. The results of the study showed that the personalization of the gestures reduced the physical and mental workload and was preferred by the participants, while overall the workload of the tasks did not significantly differ. Furthermore, the high system usability scale (SUS) score of the application, with a mean of 79.25, indicates the overall usability of the component. Additionally, the gesture recognition accuracy of M2O2P was measured as 99.05%, which is similar to the results of state-of-the-art applications. Full article
(This article belongs to the Special Issue Intelligent Factory 4.0: Advanced Production and Automation Systems)
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15 pages, 3647 KiB  
Article
Solution of Spatial Transformation Relationship of Similar Ruled Surfaces Based on Registration of Divided Regions
by Feiyan Han, Zhitao Hu, Longlong He, Xianlong Peng, Manzhi Yang and Chuanwei Zhang
Machines 2022, 10(10), 956; https://doi.org/10.3390/machines10100956 - 19 Oct 2022
Viewed by 1026
Abstract
Since the geometric transformation relationship of similar surfaces with complex features, such as local deformation and curvature changes, is hard to be solved through global registration, this paper proposes a method for solving the spatial transformation relationship of similar ruled surfaces based on [...] Read more.
Since the geometric transformation relationship of similar surfaces with complex features, such as local deformation and curvature changes, is hard to be solved through global registration, this paper proposes a method for solving the spatial transformation relationship of similar ruled surfaces based on registration of divided regions. First, an adaptive region division algorithm is proposed to divide similar surfaces, and then, an improved registration algorithm is proposed by adding two constraints which are the curvature feature and differential geometric features of point clouds. Through this improved registration algorithm, the geometric transformation relationship of each sub-region can be solved, and then the spatial geometric transformation relationship of the overall similar surface can be established. Moreover, the improved registration algorithm can ensure that the differential geometric properties of corresponding points are similar after registration, which may provide a basis for mapping and reuse of process knowledge between corresponding points on similar surfaces. Finally, two similar ruled surface blades are taken as examples for simulation verification, the results show that the maximum registration error of each sub-region is 0.025 mm, which is within the allowable error range, and the registration speed of the proposed algorithm is better than the S-ICP algorithm. This proves that the method in this paper is feasible and effective. Full article
(This article belongs to the Section Advanced Manufacturing)
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15 pages, 3574 KiB  
Article
Geometric Design and Dynamic Analysis of a Compact Cam Reducer
by Tsung-Chun Lin, Michael Schabacker, Yi-Lun Ho, Tsu-Chi Kuo and Der-Min Tsay
Machines 2022, 10(10), 955; https://doi.org/10.3390/machines10100955 - 19 Oct 2022
Cited by 2 | Viewed by 2101
Abstract
In this paper, the compact reducer which can be used as a rigid drive mechanism with a high-speed reduction ratio is systematically studied for kinematics and dynamics. The speed ratio is determined by the number of cam lobes and engaged rollers. The eccentric [...] Read more.
In this paper, the compact reducer which can be used as a rigid drive mechanism with a high-speed reduction ratio is systematically studied for kinematics and dynamics. The speed ratio is determined by the number of cam lobes and engaged rollers. The eccentric rotating conjugate lobe cam profile is synthesized by using the rigid body transformation method. To characterize the input torque based on Newton’s second law, the transmission forces of the resisting and driven multi-roller are proportional to the arm length of each actuating roller found by its geometric vector. In consideration of machining undercutting, roller limit load, and contact stresses, favorable designs can be achieved by adjusting the cam size, turret dimension, eccentricity, and roller size. Together with experimental tests, a prototype of the lobe cam reducer is made to verify the feasibility of the proposed design procedure and to investigate its kinematic and dynamic characteristics for speed reduction ratios, torques, and transmission efficiency. Full article
(This article belongs to the Section Machine Design and Theory)
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16 pages, 4977 KiB  
Article
Effects of Laminar, Turbulent, and Slip Conditions in a Fluid Film on a Dry Gas Seal
by Mibbeum Hahn, Youngjun Park, Minsoo Kang, Sanghyun Jun and Gunhee Jang
Machines 2022, 10(10), 954; https://doi.org/10.3390/machines10100954 - 19 Oct 2022
Cited by 2 | Viewed by 1528
Abstract
A dry gas seal is a mechanical seal that prevents leakage of gas from rotating machines utilizing gas as a medium. Fluid film in a dry gas seal can exhibit laminar, turbulent, and slip behavior due to operating conditions and design parameters. A [...] Read more.
A dry gas seal is a mechanical seal that prevents leakage of gas from rotating machines utilizing gas as a medium. Fluid film in a dry gas seal can exhibit laminar, turbulent, and slip behavior due to operating conditions and design parameters. A modified Reynolds equation that considers the effects of laminar, turbulent, and slip behavior of a fluid film was proposed and solved using the finite-element and Newton–Raphson methods to calculate the pressure, opening force, and leakage rate. The accuracy of the developed program was verified by comparing the simulated pressure with that of prior research, and the measured leakage with simulated leakage. The characteristics of a T-groove dry gas seal were investigated according to laminar, turbulent, and slip behavior in the fluid film. The results show that the effects of laminar, turbulent, and slip behavior in a fluid film on a dry gas seal should be considered to accurately predict the characteristics of a dry gas seal. Full article
(This article belongs to the Special Issue 10th Anniversary of Machines—Feature Papers in Turbomachinery)
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18 pages, 6322 KiB  
Article
Piecewise Decoupling Tool Orientation Re-Scheduling for Four-Axis Reciprocal Toolpaths of Blades Based on S-θ Plane with Monotonicity Constraint
by Jingsong Li, Dening Song, Peiyao Li, Qiang Zhang, Jinghua Li and Jianwei Ma
Machines 2022, 10(10), 953; https://doi.org/10.3390/machines10100953 - 19 Oct 2022
Viewed by 1467
Abstract
Reciprocal toolpaths with four-axis simultaneous motion of five-axis or four-axis machine tools are commonly used in the machining of blades which are widely applied in high-end equipment such as the aero-engine and the marine steam turbine. Due to the complex geometry of the [...] Read more.
Reciprocal toolpaths with four-axis simultaneous motion of five-axis or four-axis machine tools are commonly used in the machining of blades which are widely applied in high-end equipment such as the aero-engine and the marine steam turbine. Due to the complex geometry of the blades, the tool orientation always suffers from frequent swing for this kind of toolpaths, which induces unnecessary acceleration/deceleration of the feed axes, thus degrading processing efficiency and quality. Although there are tool orientation optimization methods aiming at solving the above problem, they are mainly proposed for universal processing of the toolpaths for complex surfaces. Different from them, this paper proposes a piecewise decoupling tool orientation re-scheduling method for this kind of toolpath specifically, which takes full use of the characteristic of the reciprocal toolpaths of the blades, and takes the monotonous variation of rotation axes as an additional constraint. The re-scheduling process is realized based on the construction of a S-θ plane, where the scheduling problem is converted to the adjustment of a S-θ curve inside a feasible channel. Through two procedures, namely linearization scheduling and control-point assigning-based smoothing, the tool orientation path expressed by the S-θ curve can be effectively scheduled in a piecewise manner, and the smoothness between two adjacent pieces of the toolpaths can be ensured directly. The whole algorithm is lightweight and does not involve complex iterative operations or functional optimization solutions. Simulation and experimental tests verify the feasibility and superiority of this method. The results show that the machining efficiency of the blade is improved by 24.5%, due to the reduction of the requirement on highest feed-axis kinematics parameters after rescheduling. In addition, compared with the existing methods, the proposed method not only can improve the dynamics of feed axes in multi-axis machining, but also has advantages in computational complexity and monotonic variation property of the tool orientation. Full article
(This article belongs to the Special Issue Recent Progress of Thin Wall Machining)
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15 pages, 4382 KiB  
Technical Note
Robust Anti-Jamming Algorithm Based on Transmit/Receive Time-Sharing Technology
by Baiyu Li, Zukun Lu, Jie Song, Wei Xiao, Jia Qiao, Long Huang, Zhibin Xiao and Baojun Lin
Machines 2022, 10(10), 952; https://doi.org/10.3390/machines10100952 - 19 Oct 2022
Viewed by 1540
Abstract
Transmit/Receive (T/R) time-sharing is a critical technology to ensure accurate space–time reference information of navigation signals, which solves the problem of co-channel interference between receiver and transmitter. The rapid development of the electronic information industry has led to severe frequency band conflicts between [...] Read more.
Transmit/Receive (T/R) time-sharing is a critical technology to ensure accurate space–time reference information of navigation signals, which solves the problem of co-channel interference between receiver and transmitter. The rapid development of the electronic information industry has led to severe frequency band conflicts between different electronic systems. Satellite navigation receivers must take measures to suppress interference to eliminate the effects of narrowband interference, mainly unintentional interference. Time-domain anti-jamming is widely used in navigation receivers for its simple and easy advantages in ensuring the validity and stability of navigation data. However, because the satellite-ground link receivers adopt transmit/receive time-sharing technology to realize the bidirectional measurement and communication function of the link, the stability of the data solution is greatly affected by anti-interference in the time domain. The anti-jamming filter of the traditional navigation receiver usually re-converges from the initial state in each signal-receiving time slot, which leads to the receiver losing high volume data due to repeated convergence. This paper proposes a robust time-domain anti-jamming technology based on transmit/receive time-sharing technology. The continuity and stability of the interference signal are used to obtain the preliminary information of the periodic transceiver. The results show that robust anti-jamming technology based on a T/R time-sharing navigation signal can effectively improve the carrier-to-noise ratio loss and data loss caused by traditional time-domain anti-jamming technology, reduce the convergence time to nanosecond level, and has bright prospects in the future application of other navigation systems. Full article
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17 pages, 4100 KiB  
Article
Dynamic Friction-Slip Model Based on Contact Theory
by Hui Wang, Jiwen Cui, Jianwei Wu and Jiubin Tan
Machines 2022, 10(10), 951; https://doi.org/10.3390/machines10100951 - 19 Oct 2022
Cited by 1 | Viewed by 1948
Abstract
In ultra-precision positioning equipment, the positioning accuracy is affected by the friction characteristics, especially the pre-slip stage. At present, the research on friction mainly includes contact theory and the dynamic friction process. There is no time variable in contact theory models, so they [...] Read more.
In ultra-precision positioning equipment, the positioning accuracy is affected by the friction characteristics, especially the pre-slip stage. At present, the research on friction mainly includes contact theory and the dynamic friction process. There is no time variable in contact theory models, so they only apply to the stage of static contact, while the establishment of a friction dynamics model depends on parameter identification and cannot reflect the influence of a rough morphology and load. Therefore, neither theory can elucidate the ultra-precise slip mechanism. In this paper, maximum static friction force, tangential stiffness, and tangential damping models of contact surfaces were deduced through fractal contact theory. By substituting the contact parameters into the modified LuGre model, a dynamic slip model of the mask was established. Finally, the above model was verified by a reticle dynamic slip measurement system. The experimental results showed that in the pre-slip stage of the reticle, with an increase in the normal external load, the slippage of the reticle decreased. The theoretical value calculated by the model was basically consistent with the experimental value, and the slippage of the reticle mainly originated from the tangential deformation and relative sliding of the contact surface. With the increase in the normal external load, the proportion of the tangential deformation in the sliding of the entire contact surface was larger. For the change in slippage during different motion stages, the theoretical value was close to the experimental value after eliminating system errors such as vibration and fiber bending, which proved the correctness of the model in this paper. Full article
(This article belongs to the Section Friction and Tribology)
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17 pages, 8924 KiB  
Article
Optimization of Hammer Peening Process for Gas Turbine Rotor Straightening
by Taewung Kim and Taehyung Kim
Machines 2022, 10(10), 950; https://doi.org/10.3390/machines10100950 - 19 Oct 2022
Cited by 1 | Viewed by 1572
Abstract
Some rotors are bent permanently due to high operating temperatures, repeated transition periods, and so on. Rotors with large deformations often require straightening processes. The goal of this study is to develop a method to determine the optimal locations and strengths of hammer [...] Read more.
Some rotors are bent permanently due to high operating temperatures, repeated transition periods, and so on. Rotors with large deformations often require straightening processes. The goal of this study is to develop a method to determine the optimal locations and strengths of hammer peening for straightening gas turbine rotors. A set of parametric hammer peening simulations were performed for various dimensions of straight rotors and peening locations. The deformed geometries of the rotor from the parametric simulations were presented as curvature vectors. These curvature vectors were fitted using an empirical function. For a given initial geometry of the rotor and hammer peening plans, the post-peening geometry of the rotor was predicted by superimposing the initial curvature and newly induced curvature. An optimization statement was defined to determine a set of hammer peening locations and strengths. Constraints were imposed to exclude areas where hammer peening could not be performed such as locations for bearings. The proposed method provides an optimal hammer peening plan for the given runout data. The proposed method was validated against a series of hammer peening test results for a simple shaft. The developed method can be applied to other types of rotor straightening methods such as hot spotting. Full article
(This article belongs to the Special Issue Diagnostics and Optimization of Gas Turbine)
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20 pages, 4363 KiB  
Article
Shape Accuracy Improvement in Selective Laser-Melted Ti6Al4V Cylindrical Parts by Sliding Friction Diamond Burnishing
by Gyula Varga, Gergely Dezső and Ferenc Szigeti
Machines 2022, 10(10), 949; https://doi.org/10.3390/machines10100949 - 19 Oct 2022
Cited by 1 | Viewed by 1283
Abstract
Additively manufactured metallic parts usually need postprocessing in order to achieve required shape accuracy. Cylindrical test specimens were produced by selective laser melting from Ti6Al4V powder material with different processing parameters. The aim of postprocessing was modification of shape accuracy. Sliding friction diamond [...] Read more.
Additively manufactured metallic parts usually need postprocessing in order to achieve required shape accuracy. Cylindrical test specimens were produced by selective laser melting from Ti6Al4V powder material with different processing parameters. The aim of postprocessing was modification of shape accuracy. Sliding friction diamond burnishing was applied as the postprocessing method. A five-factor, two-level full factorial design of experiment was implemented with factors being infill laser power, infill laser scan speed, burnishing speed, feed and force. Improvement ratios of two roundness parameters were defined, calculated from experimental data, and studied by main effect and interaction analysis. It has been demonstrated that burnishing feed has the largest main effect to improvement in roundness total and cylindricity. Additionally, parameters of both selective laser melting and diamond burnishing appear in three largest interaction terms. Empirical functions were fit to measurement data. Results show that improvement in roundness parameters are strongly nonlinear functions of all factors. Full article
(This article belongs to the Special Issue Additive Manufacturing of Machine Components)
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19 pages, 2566 KiB  
Article
Bearing Fault Diagnosis for Time-Varying System Using Vibration–Speed Fusion Network Based on Self-Attention and Sparse Feature Extraction
by Fulin Chi, Xinyu Yang, Siyu Shao and Qiang Zhang
Machines 2022, 10(10), 948; https://doi.org/10.3390/machines10100948 - 18 Oct 2022
Cited by 4 | Viewed by 2104
Abstract
Nowadays, most deep-learning-based bearing fault diagnosis methods are studied under the condition of steady speed, while the performance of these models cannot be fully played under time-varying conditions. Therefore, in order to facilitate the practical application of a deep learning model in bearing [...] Read more.
Nowadays, most deep-learning-based bearing fault diagnosis methods are studied under the condition of steady speed, while the performance of these models cannot be fully played under time-varying conditions. Therefore, in order to facilitate the practical application of a deep learning model in bearing fault diagnosis, a vibration–speed fusion network is proposed, which utilizes a transformer with a self-attention module to extract vibration features and utilizes a sparse autoencoder (SAE) network to extract sparse features from speed pulse signal. The vibration–speed fusion network enables the efficient fusion of different signals in a high-dimensional vector space with a high degree of model interpretability, without additional signal processing steps. After tuning the hyperparameters of the network, the key segments of the bearing’s time-domain vibration signals can be optimally extracted, the network performance is much better than traditional deep learning methods, and the classification accuracy can reach 95.18% and 99.85% on the two public bearing datasets from the Xi’an Jiaotong University and the University of Ottawa. Full article
(This article belongs to the Special Issue Advances in Bearing Modeling, Fault Diagnosis, RUL Prediction)
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24 pages, 12925 KiB  
Article
A Hierarchical Energy Management Strategy for 4WD Plug-In Hybrid Electric Vehicles
by Zhiqi Guo, Jianhua Guo, Liang Chu, Chong Guo, Jincheng Hu and Zhuoran Hou
Machines 2022, 10(10), 947; https://doi.org/10.3390/machines10100947 - 18 Oct 2022
Cited by 5 | Viewed by 1572
Abstract
In the field of new energy vehicles, 4WD PHEVs show strong energy-saving potential. A single energy management strategy, nevertheless, has difficulty achieving the energy-saving potential due to the complex, nonlinear energy system of the 4WD PHEV. To cope with it, a hierarchical energy [...] Read more.
In the field of new energy vehicles, 4WD PHEVs show strong energy-saving potential. A single energy management strategy, nevertheless, has difficulty achieving the energy-saving potential due to the complex, nonlinear energy system of the 4WD PHEV. To cope with it, a hierarchical energy management strategy (H-EMS) for 4WD PHEVs is proposed in this paper to achieve energy management optimization. Firstly, the future speed information is predicted by the speed prediction method, and the upper energy management strategy adopts the model predictive control (MPC) based on the future speed information to carry out the power source distribution between the engine and the battery. Secondly, the lower energy management strategy performs the power component distribution of the front motor and the rear motor based on an equivalent consumption minimization strategy (ECMS). Finally, the simulation based on MATLAB/Simulink is performed, validating that the proposed method has more energy-saving capabilities, and the economy is improved by 11.87% compared with the rule-based (RB) energy management strategies. Full article
(This article belongs to the Special Issue Emerging Technologies in New Energy Vehicle)
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19 pages, 8520 KiB  
Article
Vibration Propagation Characteristics of Micro-Milling Tools
by Binghui Jia
Machines 2022, 10(10), 946; https://doi.org/10.3390/machines10100946 - 18 Oct 2022
Cited by 1 | Viewed by 1851
Abstract
Micro-milling tools are usually used for the 3D precision processing of micro metal parts under ultra-high speed. However, due to the structural characteristics of small scale, variable cross-section, and weak stiffness, the vibration of micro-milling tools is weak and easily mutates, which can [...] Read more.
Micro-milling tools are usually used for the 3D precision processing of micro metal parts under ultra-high speed. However, due to the structural characteristics of small scale, variable cross-section, and weak stiffness, the vibration of micro-milling tools is weak and easily mutates, which can potential cause great harm to the stability and machining accuracy of machine tools. To reveal the transfer law of micro-milling tool vibration, guiding the method selection of tool vibration measurement and providing new means for mechanical model verification; firstly, the vibration mechanics model and vibration transfer matrix of the micro-milling tool were established. The vibration propagation characteristics of the micro-milling tool were analysed in contrast with the time domain and frequency domain, taking two representative micro-milling tools, Tool A and Tool B, as examples which with different cross-sections and structural parameters. Secondly, a micro-milling tool vibration measurement experimental system was set up and a sensor array with four optical fibre displacement sensors was used to obtain the vibration displacements at different positions of the tool under pulse and start-stop excitation. Finally, the results show the following: for Tool A, the max vibration displacement of the measurement of point 1 is about 3.5 times of measurement point 2 but near 18 times the measurement of point 3; meanwhile, compared with measurement point 1, the 16.8 kHz signal disappeared in measurement point 2, measurement point 3 and measurement point 4. However, for Tool B, the max vibration displacement of measurement point 1 is about 11.24 times the measurement of point 2; in contrast, the signal strength of the measurement of point 3 and point 4 is too weak to compare and analyse, although there are three resonant frequencies (10.2 kHz, 17.6 kHz, and 26.7 Hz) of Tool B based on the signal of measurement point 1, the 26.7 kHz signal disappeared in measurement point 2. The vibration amplitude of the tool tip decreases rapidly in the process of tool transfer, a bigger ratio cross-section with bigger attenuation of vibration amplitude and smaller size will aggravate this process. This study provides a reference for the selection of measuring points of micro-milling tool vibration displacement. Full article
(This article belongs to the Special Issue Vibration and Acoustic Analysis of Components and Machines)
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16 pages, 3240 KiB  
Article
Teaching Motion Control in Mechatronics Education Using an Open Framework Based on the Elevator Model
by Filippo Sanfilippo, Martin Økter, Tine Eie and Morten Ottestad
Machines 2022, 10(10), 945; https://doi.org/10.3390/machines10100945 - 18 Oct 2022
Cited by 3 | Viewed by 2378
Abstract
Universities and other educational institutions may find it difficult to afford the cost of obtaining cutting-edge teaching resources. This study introduces the adoption of a novel open prototyping framework in the context of mechatronics education, employing low-cost commercial off-the-shelf (COTS) components and tools [...] Read more.
Universities and other educational institutions may find it difficult to afford the cost of obtaining cutting-edge teaching resources. This study introduces the adoption of a novel open prototyping framework in the context of mechatronics education, employing low-cost commercial off-the-shelf (COTS) components and tools for the motion control module. The goal of this study is to propose a novel structure for the motion control module in the engineering mechatronics curriculum. The objective is to foster a new teaching method. From a methodology perspective, students are involved in a series of well-organised theoretical lectures as well as practical, very engaging group projects in the lab. To help students understand, draw connections, and broaden their knowledge, the methods of surface learning and deep learning are frequently mixed thoroughly. The structure of the course as well as the key topics are discussed. The proposed open framework, which consists of an elevator model, is presented in details. Students’ early evaluation indicates that the course organisation and subjects are successful and beneficial. Full article
(This article belongs to the Special Issue Modeling, Sensor Fusion and Control Techniques in Applied Robotics)
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12 pages, 2739 KiB  
Article
Muscle Selection Using ICA Clustering and Phase Variable Method for Transfemoral Amputees Estimation of Lower Limb Joint Angles
by Xingyu Liu, Qing Wei, Hongxu Ma, Honglei An and Yi Liu
Machines 2022, 10(10), 944; https://doi.org/10.3390/machines10100944 - 17 Oct 2022
Cited by 2 | Viewed by 1656
Abstract
Surface electromyography(sEMG) signals are used extensively in the study of lower limb locomotion, capturing and extracting information from various lower limb muscles as input for powered prostheses. Many transfemoral amputees have their lower limbs completely removed below the knee due to disease, accident [...] Read more.
Surface electromyography(sEMG) signals are used extensively in the study of lower limb locomotion, capturing and extracting information from various lower limb muscles as input for powered prostheses. Many transfemoral amputees have their lower limbs completely removed below the knee due to disease, accident or trauma. The patients only have the muscles of the thigh and cannot use the muscles of the lower leg as a signal source for sEMG. In addition, wearing sEMG sensors can cause discomfort to the wearer. Therefore, the number of sensors needs to be minimized while ensuring recognition accuracy. In this paper, we propose a novel framework to select the position of sensors and predict joint angles according to the sEMG signals from thigh muscles. Specifically, a method using ICA clustering is proposed to statistically analyze the similarity between muscles. Additionally, a mapping relationship between sEMG and lower limb joint angles is established by combining the BP network and phase variable method, compared with the mapping using only neural networks. The results show that the proposed method has higher estimation accuracy in most of the combinations. The best muscle combination is vastus lateralis (VL) + biceps femoris (BF) + gracilis (GC) (γknee = 0.989, γankle = 0.985). The proposed method will be applied to lower limb-powered prostheses for continuous bioelectric control. Full article
(This article belongs to the Special Issue Smart Machines: Applications and Advances in Human Motion Analysis)
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25 pages, 1918 KiB  
Article
Adaptive Compensation Tracking Control for Time-Varying Delay Nonlinear Systems with Unknown Actuator Dead Zone
by Libin Ma and Mao Wang
Machines 2022, 10(10), 943; https://doi.org/10.3390/machines10100943 - 17 Oct 2022
Viewed by 1087
Abstract
This paper concerns the problem of adaptive compensation tracking control for a class of time-varying delay nonlinear systems with unknown structures and unknown actuator dead zones where time-varying delays are unknown. First, a variable separation approach is used to overcome the difficulty in [...] Read more.
This paper concerns the problem of adaptive compensation tracking control for a class of time-varying delay nonlinear systems with unknown structures and unknown actuator dead zones where time-varying delays are unknown. First, a variable separation approach is used to overcome the difficulty in dealing with a nonstrict-feedback structure, and multilayer neural networks are used to approximate the unknown nonlinear structures with time-varying delays. On this basis, we designed an adaptive multilayer neural-network compensation controller to reduce the error of multilayer neural networks. Furthermore, for unknown actuator dead zones, this paper separates the controller and adopts multilayer neural networks to deal with unknown actuator dead zones. In order to reduce the error of the dead-zone controller, wer designed an adaptive compensation controller for the dead zones. Lastly, this paper proves the stability of the systems with the Lyapunov method, and simulation results demonstrate the effectiveness of the scheme. Full article
(This article belongs to the Section Automation and Control Systems)
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23 pages, 13717 KiB  
Article
Research on Heat Transfer through a Double-Walled Heat Shield of a Firefighting Robot
by Amado Ștefan, Lucian Ștefăniță Grigore, Cristian Molder, Ionica Oncioiu, Bogdan Vlădescu, Daniel Constantin, Damian Gorgoteanu, Răzvan-Ionuț Bălașa and Ștefan Mustață
Machines 2022, 10(10), 942; https://doi.org/10.3390/machines10100942 - 17 Oct 2022
Cited by 1 | Viewed by 2087
Abstract
Burning forests, petrochemical installations and material warehouses generate very large fields and thermal gradients, which means human intervention to extinguish the fire is greatly limited. For that reason, the use of robots is recommended, but because of high temperature, they have to be [...] Read more.
Burning forests, petrochemical installations and material warehouses generate very large fields and thermal gradients, which means human intervention to extinguish the fire is greatly limited. For that reason, the use of robots is recommended, but because of high temperature, they have to be equipped with protective thermal shields. This article is an analytical, numerical, and experimental study on how a double-wall, stainless steel heat shield influenced the thermal gradients acting on a firefighting robot. Following the analytical analysis at a maximum temperature of 350 °C, it was possible to identify the parameters that must be measured to be correlated with those from finite element analysis (FEM) analysis. Experimental tests showed a decrease in temperature behind the shield due to the stainless steel and the double-walled. The main conclusions and contributions of this paper consist of the realization of a finite difference model with FEM that takes into account conduction, convection, and radiation. It also highlights the benefits of using a multilayer shield. Full article
(This article belongs to the Special Issue Heterogeneity in Intelligent Mobile Robots and Systems)
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16 pages, 5829 KiB  
Article
Selection of Constitutive Material Model for the Finite Element Simulation of Pressure-Assisted Single-Point Incremental Forming
by Ali Abdelhafeez Hassan, Gökhan Küçüktürk, Hurcan Volkan Yazgin, Hakan Gürün and Duran Kaya
Machines 2022, 10(10), 941; https://doi.org/10.3390/machines10100941 - 17 Oct 2022
Cited by 2 | Viewed by 1774
Abstract
Pressure-assisted single-point incremental forming (PA-SPIF) is one of the emerging forming techniques for sheet metals that have been the subject of rigorous research over the past two decades. Understanding of its forming mechanisms and capabilities is growing as a result. Open gaps are [...] Read more.
Pressure-assisted single-point incremental forming (PA-SPIF) is one of the emerging forming techniques for sheet metals that have been the subject of rigorous research over the past two decades. Understanding of its forming mechanisms and capabilities is growing as a result. Open gaps are still present in material constitutive modelling for accurate numerical predictions and finite-element simulations as the characteristics of localised deformation behaviour in SPIF are different from those of conventional sheet metal forming. The current investigation focused on the comparison of three different material models for the finite-element analysis of PA-SPIF of cold-rolled, dual-phase steel DP600. Experimental trials using different fluid pressures showed good agreement with simulation results with discrepancies in deformed blank thickness and shape geometry predictions of 3–11% and 10–21%, respectively. Within the tested materials and range of parameters, the fracture-forming-limit diagram (FFLD) material model was identified to be of superior accord with experiments. Full article
(This article belongs to the Special Issue High Performance and Hybrid Manufacturing Processes)
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20 pages, 6206 KiB  
Article
Improving Industrial Robot Positioning Accuracy to the Microscale Using Machine Learning Method
by Vytautas Bucinskas, Andrius Dzedzickis, Marius Sumanas, Ernestas Sutinys, Sigitas Petkevicius, Jurate Butkiene, Darius Virzonis and Inga Morkvenaite-Vilkonciene
Machines 2022, 10(10), 940; https://doi.org/10.3390/machines10100940 - 17 Oct 2022
Cited by 9 | Viewed by 3479
Abstract
Positioning accuracy in robotics is a key issue for the manufacturing process. One of the possible ways to achieve high accuracy is the implementation of machine learning (ML), which allows robots to learn from their own practical experience and find the best way [...] Read more.
Positioning accuracy in robotics is a key issue for the manufacturing process. One of the possible ways to achieve high accuracy is the implementation of machine learning (ML), which allows robots to learn from their own practical experience and find the best way to perform the prescribed operation. Usually, accuracy improvement methods cover the generation of a positioning error map for the whole robot workspace, providing corresponding correction models. However, most practical cases require extremely high positioning accuracy only at a few essential points on the trajectory. This paper provides a methodology for the online deep Q-learning-based approach intended to increase positioning accuracy at key points by analyzing experimentally predetermined robot properties and their impact on overall accuracy. Using the KUKA-YouBot robot as a test system, we perform accuracy measurement experiments in the following three axes: (i) after a long operational break, (ii) using different loads, and (iii) at different speeds. To use this data for ML, the relationships between the robot’s operating time from switching on, load, and positioning accuracy are defined. In addition, the gripper vibrations are evaluated when the robot arm moves at various speeds in vertical and horizontal planes. It is found that the robot’s degrees of freedom (DOFs) clearances are significantly influenced by operational heat, which affects its static and dynamic accuracy. Implementation of the proposed ML-based compensation method resulted in a positioning error decrease at the trajectory key points by more than 30%. Full article
(This article belongs to the Special Issue Industrial Process Improvement by Automation and Robotics)
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22 pages, 14922 KiB  
Article
Virtual Engineering and Commissioning to Support the Lifecycle of a Manufacturing Assembly System
by Sergey Konstantinov, Fadi Assad, Bilal Ahmad, Daniel A. Vera and Robert Harrison
Machines 2022, 10(10), 939; https://doi.org/10.3390/machines10100939 - 16 Oct 2022
Cited by 8 | Viewed by 2399
Abstract
Prior to the physical build of the industrial automation system, some challenges arise, such as processes’ cycle times calculations, ergonomics and safety evaluation, and the integration of separate machines to the complete production shops. This, in turn, requires reconfiguring the processes and component [...] Read more.
Prior to the physical build of the industrial automation system, some challenges arise, such as processes’ cycle times calculations, ergonomics and safety evaluation, and the integration of separate machines to the complete production shops. This, in turn, requires reconfiguring the processes and component parameters. As a result, the lifecycle of the system development is prolonged, and the potential for erroneous performance increases. In modern digital manufacturing environments, virtual engineering (VE) and virtual commissioning (VC) serve as effective tools to tackle the aforementioned problems and their consequences. The virtual models developed for VE and VC not only assist system developers in the physical build stage but also in the following stages of the system lifecycle by providing a common virtual model, a digital twin (DT), of the manufacturing processes and the product. This developed model should possess the ability to simulate the system behaviour, e.g., the mechanics, kinematics, speed and acceleration profiles. Three stakeholders are involved in the development process: the machine builder, system integrator and end user. The current work focuses on the virtual engineering approach to support the entire lifecycle of a manufacturing system from the machine builder, system integrator and end user perspectives. For this purpose, it puts forward a systematic methodology of implementing VC and VE using a toolset developed by the Automation Systems Group at the University of Warwick within an industrial project. The suggested methodology is illustrated in a case study where a digital twin of a physical station was modelled, developed and tested in parallel with the physical machine development and build. Finally, the benefits and limitations are highlighted based on the gained outcomes and the implemented activities. Full article
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21 pages, 10163 KiB  
Article
Developing and Testing the Proto Type Structure for Micro Tool Fabrication
by Hang Xiao, Xiaolong Hu, Shaoqing Luo and Wei Li
Machines 2022, 10(10), 938; https://doi.org/10.3390/machines10100938 - 16 Oct 2022
Cited by 1 | Viewed by 1438
Abstract
Compared with traditional machine tools, the micro machine tools have advantages of small volume, low cost, less energy consumption, high efficiency and high flexibility. Therefore, it is regarded as an important equipment for micro-cutting machining which has been used widely all over the [...] Read more.
Compared with traditional machine tools, the micro machine tools have advantages of small volume, low cost, less energy consumption, high efficiency and high flexibility. Therefore, it is regarded as an important equipment for micro-cutting machining which has been used widely all over the world and. As a key component of the micro-cutting machine tools, the body structure directly influences the machining performance. Thus, an integral column and base structure for micro machining tools was proposed in this work, and the detailed structural parameters were designed based on parameter analysis. Besides, the static and dynamic performance of the proposed machine were analyzed and compared between the integral structure and the separated one. The deformation and stress of the proposed structures under typical working conditions were studied by numerical simulation, along with the natural frequencies, vibration modes and frequency response peaks. Further, optimization was performed on the integral body structure, the prototype of the micro-machine tool was trial-produced, and the positioning accuracy of each coordinate axis was qualitatively analyzed. In addition, the micro-milling test was carried out with 6061 aluminum alloy to show the performance of the novel cutting machine. The results revealed that the proposed integrated micro-machine bed structure is superior to the separated structure in terms of static deformation and harmonic response characteristics, with good comprehensive mechanical properties, greatly improved static and dynamic performance of the machine tool, significantly improved structural accuracy, improved processing quality of the specimen and good application value. Full article
(This article belongs to the Special Issue High Precision Abrasive Machining: Machines, Processes and Systems)
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15 pages, 3645 KiB  
Article
Evaluating the Influence of Data Entropy in the Use of a Smart Equipment for Traffic Management at Border Check Point
by Florin Rusca, Aura Rusca, Eugen Rosca, Catalin Coman, Stefan Burciu and Cristina Oprea
Machines 2022, 10(10), 937; https://doi.org/10.3390/machines10100937 - 16 Oct 2022
Cited by 1 | Viewed by 1295
Abstract
The transit through a Border Check Point of cargo vehicles supposes, in the case of the Romanian highway network, the carrying out of a process of weighing and verifying of transport licenses. The limited number of weighing equipment and the long duration of [...] Read more.
The transit through a Border Check Point of cargo vehicles supposes, in the case of the Romanian highway network, the carrying out of a process of weighing and verifying of transport licenses. The limited number of weighing equipment and the long duration of these processes cause large queues and long waiting times. A solution for these problems is to use smart equipment to identify the cargo vehicles and to separate the vehicles that require weighing from exempted ones. The separation process is made using external input data. The quality of received data can generate some dysfunctionality in the separation process. The discrete simulation model can be used to evaluate the influence of the uncertainty over the system serving parameters. A study case is developed for a real situation using real data collected from a Romanian Highway Traffic Control Center (HTMC). The results are used in the implementation of the new smart equipment in a Romanian Border Check Point. Full article
(This article belongs to the Topic Intelligent Systems and Robotics)
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21 pages, 3816 KiB  
Article
Unbalance Prediction of Low Pressure Rotor Based on Mechanism and Data Fusion
by Mingwei Wang, Huibin Zhang, Lei Liu, Jingtao Zhou, Lu Yao, Xin Ma and Manxian Wang
Machines 2022, 10(10), 936; https://doi.org/10.3390/machines10100936 - 16 Oct 2022
Cited by 2 | Viewed by 1397
Abstract
The assembly, as the core part of low-pressure rotor manufacturing, is of great importance to ensure its unbalance. Low-voltage rotor assembly is a multi-process process influenced by the quality of part machining, assembly process, and assembly quality, resulting in unbalance that is difficult [...] Read more.
The assembly, as the core part of low-pressure rotor manufacturing, is of great importance to ensure its unbalance. Low-voltage rotor assembly is a multi-process process influenced by the quality of part machining, assembly process, and assembly quality, resulting in unbalance that is difficult to predict during the assembly process. The unbalance measurement in the assembly process is important for the subsequent process optimization. Therefore, in order to achieve the prediction of unbalance measurement in the assembly process, this paper proposes an unbalance measurement prediction method based on mechanism and data fusion. Firstly, through research and analysis, the influencing factors of unbalance are determined, the low-pressure rotor blade sequencing mechanism model is established, and the blade sequencing optimization is realized by using reinforcement learning. Then, since the unbalance is formed after all the processes are completed and the subsequent work steps in the assembly process have not been carried out yet, the actual process parameters cannot be obtained, the semi-physical simulation method is used to combine the actual data of the assembled work steps with the theoretical data of the unassembled work steps to build a prediction model of the unbalance based on the BRNN (bidirectional recurrent neural network) network to achieve the prediction of the unbalance measurement in the assembly process. Finally, the model was validated using actual assembly process data, which proved the feasibility and effectiveness of the method. Full article
(This article belongs to the Section Machine Design and Theory)
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