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Volume 10
Issue 9
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Machines, Volume 10, Issue 9 (September 2022) – 104 articles

Cover Story (view full-size image): In this paper, the power losses of a five-phase drive system based on an indirect matrix converter (IMC) and a five-phase synchronous reluctance motor (SynRM) have been analyzed. Moreover, a control strategy is applied to decrease the power converter losses and make the system superior to the conventional one. The carrier-based pulse-width-modulation (CBPWM) method is used for this. Through the CBPWM, switching losses are kept as low as possible in this technique by ensuring that the rectifier stage experiences zero current commutation. To achieve this, the rectifier and inverter stages are synchronized so that the commutation in the rectifier stage occurs at the zero vectors of the inverter, which corresponds to a zero DC-link current. View this paper
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20 pages, 5132 KiB  
Article
An Equilibrium Decision-Making Approach for Cutting Parameters of a Novel Five-Axis Hybrid Kinematic Machining Unit
by Tengfei Tang, Haiwei Luo, Weimin Tang and Jun Zhang
Machines 2022, 10(9), 824; https://doi.org/10.3390/machines10090824 - 19 Sep 2022
Viewed by 1498
Abstract
To fully disclose the machining potential of a newly developed five-axis hybrid kinematic machining unit (HKMU), an equilibrium decision-making approach for cutting parameters is proposed. With this proposition, a response surface method-based surrogate model is developed to describe the mapping relationships between three [...] Read more.
To fully disclose the machining potential of a newly developed five-axis hybrid kinematic machining unit (HKMU), an equilibrium decision-making approach for cutting parameters is proposed. With this proposition, a response surface method-based surrogate model is developed to describe the mapping relationships between three design objectives and five cutting parameters. A multi-objective optimization model is further established to find feasible Pareto solutions to cutting parameters. Based on this, the technique for order preference by similarity to ideal solution (TOPSIS) and engineering decision preferences are adopted to make the final decision of cutting parameters. To illustrate the application of the proposed approach, a case study is carried out on face milling of an exemplary HKMU. The equilibrium decisions of three customized machining schemes lead to the machining duration, the cutting force, and the surface roughness reduction by 44%, 43%, and 9%, respectively. This result supports that the proposed equilibrium decision-making approach is able to find the best-compromised solutions for cutting parameters of the HKMU. It is expected that with minor modifications, the proposed approach can be applied to other multi-axis machining devices for finding accurate yet efficient cutting parameter solutions. Full article
(This article belongs to the Topic Robotics and Automation in Smart Manufacturing Systems)
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15 pages, 4045 KiB  
Article
Study of Heat Transfer and Leakage Characteristics of Brush Seals Based on Local Temperature Non-Equilibrium Model
by Jiahao Zhang, Meihong Liu and Neng Peng
Machines 2022, 10(9), 823; https://doi.org/10.3390/machines10090823 - 19 Sep 2022
Cited by 1 | Viewed by 1506
Abstract
In this study, to improve the accuracy of the brush seal heat transfer model, based on the finite volume method (FVM) coupled with the three-dimensional Reynold-averaged Naviers-Stokes equations (RANS) equations of the Local temperature non-equilibrium (LTNE) model, and a mathematical model of the [...] Read more.
In this study, to improve the accuracy of the brush seal heat transfer model, based on the finite volume method (FVM) coupled with the three-dimensional Reynold-averaged Naviers-Stokes equations (RANS) equations of the Local temperature non-equilibrium (LTNE) model, and a mathematical model of the heat transfer and leakage characteristics of the brush seal was established. The distribution of the pressure, flow and temperature fields of the brush seal are analyzed. User-defined function (UDF) programming was performed for the LTNE model. And the LTNE model is then compared with the local temperature equilibrium (LTE) model in terms of the factors influencing the heat transfer and leakage characteristics. The results show that the maximum brush filament temperature increases with an increases in the pressure ratio, interference, and speed for both models; the fluid flow rate increases with an increases in the pressure ratio, interference, and speed; and the leakage rate increases with an increases in the pressure ratio and decreases with an increases in interference and speed. The maximum temperature of the brush filament under the LTNE model was found to be higher than that under the LTE model, but the maximum temperature difference does not exceed 3.1%. Additionally, the fluid flow rate under the LTNE model was higher than that under the LTE model, and the flow rate difference does not exceed 3.4%. And the leakage rate under the LTNE model was lower than that under the LTE model, and the leakage rates differ by no more than 9.0%. Ultimately, numerical analysis of the brush seal under the LTNE model was found to be more effective and consistent with actual working conditions than alternative models. Full article
(This article belongs to the Special Issue Heat Transfer and Energy Harvesting in Fluid System)
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19 pages, 5826 KiB  
Article
Signal Processing of Acoustic Data for Condition Monitoring of an Aircraft Ignition System
by Umair Ahmed, Fakhre Ali and Ian Jennions
Machines 2022, 10(9), 822; https://doi.org/10.3390/machines10090822 - 19 Sep 2022
Cited by 2 | Viewed by 2617
Abstract
Degradation of the ignition system can result in startup failure in an aircraft’s auxiliary power unit. In this paper, a novel acoustics-based solution that can enable condition monitoring of an APU ignition system was proposed. In order to support the implementation of this [...] Read more.
Degradation of the ignition system can result in startup failure in an aircraft’s auxiliary power unit. In this paper, a novel acoustics-based solution that can enable condition monitoring of an APU ignition system was proposed. In order to support the implementation of this research study, the experimental data set from Cranfield University’s Boeing 737-400 aircraft was utilized. The overall execution of the approach comprised background noise suppression, estimation of the spark repetition frequency and its fluctuation, spark event segmentation, and feature extraction, in order to monitor the state of the ignition system. The methodology successfully demonstrated the usefulness of the approach in terms of detecting inconsistencies in the behavior of the ignition exciter, as well as detecting trends in the degradation of spark acoustic characteristics. The identified features proved to be robust against non-stationary background noise, and were also found to be independent of the acoustic path between the igniter and microphone locations, qualifying an acoustics-based approach to be practically viable. Full article
(This article belongs to the Special Issue Fault Detection, Diagnosis and Prognostics of Machines: Applications and Advances)
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25 pages, 1913 KiB  
Article
Human Factor Analysis of the Railway Traffic Operators
by Aleš Janota, Rastislav Pirník, Juraj Ždánsky and Peter Nagy
Machines 2022, 10(9), 820; https://doi.org/10.3390/machines10090820 - 19 Sep 2022
Cited by 4 | Viewed by 1723
Abstract
The human factor is an essential aspect of the operability and safety of many technical systems. This paper focuses on the analysis of human errors in the railway domain. The subject of human reliability analysis is the behavior of operators of station-signaling systems [...] Read more.
The human factor is an essential aspect of the operability and safety of many technical systems. This paper focuses on the analysis of human errors in the railway domain. The subject of human reliability analysis is the behavior of operators of station-signaling systems responsible for rail traffic management. We use a technique for human-error rate prediction as the 1st generation human reliability analysis to deal with task analyses, error identification and representation, and the quantification of human error probabilities. The paper contributes to the comparison of three technologically different railway traffic control systems, having different degrees of automation—from the manually operated (electro-mechanical), through semi-automated (relay-based) to almost fully automated (computer-based) station-signaling systems. We observe the frequency of individual operations performed in time intervals and calculate human error probability and human success probability values for each operation. Thus, we can analyze human reliability and compare the workload of operators working with control systems of different degrees of automation. Full article
(This article belongs to the Section Automation and Control Systems)
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18 pages, 12467 KiB  
Article
Modeling and Analysis of Clutch Nonlinear Behavior in an Automotive Driveline for Suppressing Torsional Vibration
by Junlong Qu, Wenku Shi, Juncheng Wang and Zhiyong Chen
Machines 2022, 10(9), 819; https://doi.org/10.3390/machines10090819 - 18 Sep 2022
Cited by 2 | Viewed by 1846
Abstract
Torsional vibration of the automotive driveline has significant influence on driving comfort. This study investigates the influence of clutch nonlinear behaviors on the torsional vibration of the driveline with numerical and experimental methods. A generic automobile powertrain model with 7 degrees of freedom [...] Read more.
Torsional vibration of the automotive driveline has significant influence on driving comfort. This study investigates the influence of clutch nonlinear behaviors on the torsional vibration of the driveline with numerical and experimental methods. A generic automobile powertrain model with 7 degrees of freedom is proposed considering the transient engine torque, the nonlinear characteristics of multi-stage clutch and tire slip. Taking a commercial vehicle as an example, the dynamic behaviors and inherent characteristics of the driveline system are calculated and analyzed. Based on the proposed model, the influences of the clutch parameters on driveline torsional vibration are investigated. In order to validate the proposed model and the analytical results, an optimized clutch is designed and the experiments of torsional vibration are conducted with the prototype and the optimized clutch. The analytical and experimental results demonstrate that an increase in the first end-stop angle and the main-stage hysteresis or a decrease in the second end-stop angle and the main-stage stiffness of the clutch can effectively suppress driveline torsional vibration during vehicle accelerating. Full article
(This article belongs to the Section Vehicle Engineering)
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25 pages, 2944 KiB  
Article
A Novel Sliding Mode Momentum Observer for Collaborative Robot Collision Detection
by Shike Long, Xuanju Dang, Shanlin Sun, Yongjun Wang and Mingzhen Gui
Machines 2022, 10(9), 818; https://doi.org/10.3390/machines10090818 - 17 Sep 2022
Cited by 4 | Viewed by 2122
Abstract
Safety during physical human–robot interaction is the most basic requirement for robots. Collision detection without additional sensors is an economically feasible way to ensure it. In contrast, current collision detection approaches have an unavoidable trade-off between sensitivity to collisions, signal smoothness, and immunity [...] Read more.
Safety during physical human–robot interaction is the most basic requirement for robots. Collision detection without additional sensors is an economically feasible way to ensure it. In contrast, current collision detection approaches have an unavoidable trade-off between sensitivity to collisions, signal smoothness, and immunity to measurement noise. In this paper, we present a novel sliding mode momentum observer (NSOMO) for detecting collisions between robots and humans, including dynamic and quasistatic collisions. The collision detection method starts with a dynamic model of the robot and derives a generalized momentum-based state equation. Then a new reaching law is devised, based on which NSOMO is constructed by fusing momentum, achieving higher bandwidth and noise immunity of observation. Finally, a time-varying dynamic threshold (TVDT) model is designed to distinguish between collision signals and the estimated lumped disturbance. Its coefficients are obtained through offline data recognition. The TVDT with NSOMO enables fast and reliable collision detection and allows collision position assessment. Simulation experiments and hardware tests of the 7-DOF collaborative robot are implemented to illustrate this proposed method’s effectiveness. Full article
(This article belongs to the Special Issue Advanced Data Analytics in Intelligent Industry: Theory and Practice)
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20 pages, 25367 KiB  
Article
Conceptualization and Implementation of a Reconfigurable Unmanned Ground Vehicle for Emulated Agricultural Tasks
by Raza A. Saeed, Giacomo Tomasi, Giovanni Carabin, Renato Vidoni and Karl D. von Ellenrieder
Machines 2022, 10(9), 817; https://doi.org/10.3390/machines10090817 - 16 Sep 2022
Cited by 5 | Viewed by 2469
Abstract
Small-to-medium sized systems able to perform multiple operations are a promising option for use in agricultural robotics. With this in mind, we present the conceptualization and implementation of a versatile and modular unmanned ground vehicle prototype, which is designed on top of a [...] Read more.
Small-to-medium sized systems able to perform multiple operations are a promising option for use in agricultural robotics. With this in mind, we present the conceptualization and implementation of a versatile and modular unmanned ground vehicle prototype, which is designed on top of a commercial wheeled mobile platform, in order to test and assess new devices, and motion planning and control algorithms for different Precision Agriculture applications. Considering monitoring, harvesting and spraying as target applications, the developed system utilizes different hardware modules, which are added on top of a mobile platform. Software modularity is realized using the Robot Operating System (ROS). Self- and ambient-awareness, including obstacle detection, are implemented at different levels. A novel extended Boundary Node Method is used for path planning and a modified Lookahead-based Line of Sight guidance algorithm is used for path following. A first experimental assessment of the system’s capabilities in an emulated orchard scenario is presented here. The results demonstrate good path-planning and path-following capabilities, including cases in which unknown obstacles are present. Full article
(This article belongs to the Special Issue Advances of Machine Design in Italy 2022)
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33 pages, 11280 KiB  
Article
Magnetic Field Analysis and Performance Optimization of Dual-Rotor Hybrid Excitation Generator for Automobile
by Shilong Yan, Xueyi Zhang, Jun Zhang, Yufeng Zhang, Mingjun Xu, Ting Gao and Sizhan Hua
Machines 2022, 10(9), 816; https://doi.org/10.3390/machines10090816 - 16 Sep 2022
Viewed by 3065
Abstract
Aiming at the current problems of low excitation efficiency and poor reliability of single-rotor hybrid excitation generators, the large axial length of dual-rotor structure, and difficulty in magnetic field analysis, a new type of the dual-rotor hybrid excitation generator topology with high power [...] Read more.
Aiming at the current problems of low excitation efficiency and poor reliability of single-rotor hybrid excitation generators, the large axial length of dual-rotor structure, and difficulty in magnetic field analysis, a new type of the dual-rotor hybrid excitation generator topology with high power density is proposed, with two rotors side-by-side coaxial, sharing a set of armature windings, and the magnetic fields do not interfere with each other, so the magnetic field analysis and optimization of the two rotors can be carried out separately. The magnetic density distribution of the new permanent magnet (PM) claw pole rotor is analyzed by the joint application of the equivalent magnetic circuit method and the equivalent magnetic network method, which ensures the simplicity of calculation and improves the calculation accuracy. The multi-objective optimization of the key structural parameters is carried out based on the Latin hypercube sampling–Pareto frontier solution method. The subdomain method is improved by segmented equivalence, the unique solution of the salient-pole rotor magnetic field is obtained, and the multi-objective optimization of the salient-pole rotor is used by the particle swarm algorithm. The trial prototype was experimental, and the results showed that the output characteristics of the optimized hybrid excitation generator were significantly improved, and the overall performance of the generator was improved. Full article
(This article belongs to the Section Vehicle Engineering)
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23 pages, 10311 KiB  
Article
Structural Optimization Design and Strength Test Research of Connecting Rod Assembly of High-Power Low-Speed Diesel Engine
by Wenxiang Gao, Guixin Wang, Jialiang Zhu, Ziying Fan, Xiaobo Li and Wentao Wu
Machines 2022, 10(9), 815; https://doi.org/10.3390/machines10090815 - 16 Sep 2022
Viewed by 2700
Abstract
The connecting rod assembly of a high-power low-speed diesel engine has high quality and high cost. If the connecting rod component is damaged, the whole machine may be paralyzed, resulting in serious economic losses and safety problems, so it is necessary to carry [...] Read more.
The connecting rod assembly of a high-power low-speed diesel engine has high quality and high cost. If the connecting rod component is damaged, the whole machine may be paralyzed, resulting in serious economic losses and safety problems, so it is necessary to carry out strength analysis and structure optimization, reduce the failure rate, and increase its life. This paper takes the connecting rod of a low-speed diesel engine as the research object, builds the crank connecting rod mechanism model, and carries on the strength simulation analysis through professional simulation software. During this period, the accurate S-N curve of connecting rod material is obtained through a fatigue test, and the static strength test of the connecting rod assembly is carried out by an electro-hydraulic servo universal testing machine. The numerical modeling is validated based on the test results. Therefore, the influence of the structural parameters of the cross-section and the large end transition fillet on the stress of the connecting rod is analyzed. The results show that optimizing matching between the large end fillet of the connecting rod and the long diameter of the rod section not only reduces the mass but also improves the safety factor. After optimizing the structure of the connecting rod, the mass of the connecting rod is reduced by 5.85%, the maximum stress is reduced by 13.7%, and the safety factor is increased by 16.0%. In addition, due to the low-speed diesel engine connecting rod assembly weight is big, and the simulation computation efficiency is low, this paper by studying the influence of the cross-section parameters of the rod body and the large end transition fillet on the stress of the connecting rod, fitted the empirical formula calculating the maximum stress of connecting rod, for this model and similar type in the conceptual design, technology design provides a new analysis method, improved the efficiency of structural optimization and strength analysis of connecting rod assembly, filled the research gap of strength analysis and structural optimization of low-speed diesel engine connecting rod. Full article
(This article belongs to the Section Electrical Machines and Drives)
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18 pages, 10542 KiB  
Article
Vibro-Impact Response Analysis of Collision with Clearance: A Tutorial
by Yongjie Xu, Yu Tian, Qiyu Li, Yanbin Li, Dahai Zhang and Dong Jiang
Machines 2022, 10(9), 814; https://doi.org/10.3390/machines10090814 - 16 Sep 2022
Cited by 2 | Viewed by 1429
Abstract
A collision with clearance causes obvious nonlinearity in structures, and dynamic response analysis plays an important role in predicting the mechanical performance of the structure. The general form of the nonlinear dynamic equation of a structure and the clearance modeling method are introduced, [...] Read more.
A collision with clearance causes obvious nonlinearity in structures, and dynamic response analysis plays an important role in predicting the mechanical performance of the structure. The general form of the nonlinear dynamic equation of a structure and the clearance modeling method are introduced, and the clearance-caused nonlinear term is expressed by nonlinear impact forces. Different clearance collision models of local nonlinear structures are presented. The relationships between different impact forces and clearances are analyzed by two rigid sphere models. The solution methods of the nonlinear dynamic equation are compared by a vibro-impact response, such as the Newmark-β method combined with the Newton–Raphson method, generalized α method and precise integration method. The single degree of freedom model is adopted to compare the efficiency of the different numerical integration algorithms. Taking the beam structure model as a case study, the accurate nonlinear collision model with clearance is established by using the impact force model with high accuracy, and the accuracy of the model is verified by comparing the reference model with the numerical model. Full article
(This article belongs to the Special Issue Dynamic Stability Analysis of Aerospace Structures)
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41 pages, 15400 KiB  
Review
Recent Advances in Quasi-Zero Stiffness Vibration Isolation Systems: An Overview and Future Possibilities
by Zhaozhao Ma, Ruiping Zhou and Qingchao Yang
Machines 2022, 10(9), 813; https://doi.org/10.3390/machines10090813 - 16 Sep 2022
Cited by 24 | Viewed by 5986
Abstract
In recent decades, quasi-zero stiffness (QZS) vibration isolation systems with nonlinear characteristics have aroused widespread attention and strong research interest due to their enormous potential in low-frequency vibration isolation. This work comprehensively reviews recent research on QZS vibration isolators with a focus on [...] Read more.
In recent decades, quasi-zero stiffness (QZS) vibration isolation systems with nonlinear characteristics have aroused widespread attention and strong research interest due to their enormous potential in low-frequency vibration isolation. This work comprehensively reviews recent research on QZS vibration isolators with a focus on the principle, structural design, and vibration isolation performance of various types of QZS vibration isolators. The negative-stiffness mechanism falls into two categories by different realization methods: passive and active/semi-active negative-stiffness mechanisms. Representative design, performance analysis, and practical application are elaborated for each category. The results show that passive vibration isolation systems have excellent low-frequency vibration isolation performance under specific payload and design parameters, whereas active/semi-active vibration isolation systems can better adapt to different environmental conditions. Finally, the development trends and challenges of QZS vibration isolators are summarized, and the solved and unsolved problems are highlighted. This review aims to give a comprehensive understanding of the QZS vibration isolation mechanism. It also provides guidance on designing new QZS vibration isolators for improving their vibration isolation performance and engineering applicability. Full article
(This article belongs to the Special Issue Low-Frequency Vibration Control with Advanced Technologies)
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23 pages, 14473 KiB  
Article
Simulation of Magnetorheological Plane Polishing Scratch Creation Process and Suppression Method
by Meixuan Wang, Meng Nie, Yueming Liu and Haodong Guo
Machines 2022, 10(9), 812; https://doi.org/10.3390/machines10090812 - 15 Sep 2022
Viewed by 1269
Abstract
This study was conducted to simulate the causes of, and suppress, the scratch damage on the workpiece surface during magnetorheological surface polishing. The molecular dynamics method combined with polishing contact trajectory modeling was used to simulate the scratch damage formation process, and the [...] Read more.
This study was conducted to simulate the causes of, and suppress, the scratch damage on the workpiece surface during magnetorheological surface polishing. The molecular dynamics method combined with polishing contact trajectory modeling was used to simulate the scratch damage formation process, and the scratch damage morphology model was established by analyzing the scratch damage distribution characteristics in the magnetorheological plane polishing process. The effect of different process parameters on the scratch damage characteristics was predicted by simulation, and orthogonal experiments were designed to explore the preferred polishing process parameters that could suppress the scratch damage formation. Finally, it was further verified that the formation of scratch damage can be effectively suppressed by controlling the workpiece speed, polishing disc speed, and magnetic field generator speed, and adjusting the magnetic field eccentricity distance under the premise of ensuring the surface roughness and flatness of the workpiece. Full article
(This article belongs to the Special Issue High Precision Abrasive Machining: Machines, Processes and Systems)
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22 pages, 9970 KiB  
Article
Design of a Spiral Double-Cutting Machine for an Automotive Bowden Cable Assembly Line
by André F. G. Barbosa, Raul D. S. G. Campilho, Francisco J. G. Silva, Isidro J. Sánchez-Arce, Chander Prakash and Dharam Buddhi
Machines 2022, 10(9), 811; https://doi.org/10.3390/machines10090811 - 15 Sep 2022
Cited by 2 | Viewed by 2325
Abstract
The manufacture of automotive components requires innovative technologies and equipment. Due to the competitiveness in the sector, the implementation of automatic and robotic equipment has been vital in its development to produce the largest number of products in the shortest amount of time. [...] Read more.
The manufacture of automotive components requires innovative technologies and equipment. Due to the competitiveness in the sector, the implementation of automatic and robotic equipment has been vital in its development to produce the largest number of products in the shortest amount of time. Automation leads to a significant reduction in defects and enables mass production and standardization of the final product. This work was based on the need of an automotive components’ company to increase the rate of spiral cable cutting, used as protection for Bowden (control) cables. Currently, this component, used in automotive systems, is processed with simple cutting machines and cleaning machines. Based on the design science research (DSR) methodology, this work aims to develop a machine capable of performing the cutting and cleaning of two spiral cables simultaneously and automatically. The development of this machine was based on existing machines, and the biggest challenge was the implementation of a double-cutting system. The designed machine met the initial requirements, such as enabling the simultaneous cut of two spirals, being fully automatic, doubling the output over the current solution, and fully complying with the current legislation. Full article
(This article belongs to the Special Issue Industrial Process Improvement by Automation and Robotics)
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14 pages, 7642 KiB  
Article
High-Performance Control Strategy for Low-Speed Torque of IPMSM in Electric Construction Machinery
by Zhongshen Li, Qihuai Chen, Yongjie Chen, Tianliang Lin, Haoling Ren and Wen Gong
Machines 2022, 10(9), 810; https://doi.org/10.3390/machines10090810 - 15 Sep 2022
Cited by 1 | Viewed by 1156
Abstract
Electric construction machinery with zero emission and high efficiency is considered to be a main development trend. An electric motor (EM) in electric construction machinery often needs to work at low speed or even in stalling conditions with large torque value and high [...] Read more.
Electric construction machinery with zero emission and high efficiency is considered to be a main development trend. An electric motor (EM) in electric construction machinery often needs to work at low speed or even in stalling conditions with large torque value and high work efficiency. In this paper, based on vector control of the maximum torque per ampere (MTPA) of an internal permanent magnet synchronous motor (IPMSM), a voltage and current composite observation algorithm was studied to improve IPMSM control performance at low speed. By establishing the observer model, the amplitude limited compensation for the voltage flux observation method was used to observe the EM stator flux. After being combined with the current observation method and the stator current obtained by coordinate transformation, the EM parameters in real-time can be identified for MTPA. Experimental research was carried out. The results show that the algorithm improved the speed control characteristic and output torque per unit current of the EM under low-speed working conditions. Full article
(This article belongs to the Special Issue Advanced Control of Electro-Hydraulic Systems in Industrial Area)
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16 pages, 3355 KiB  
Article
A Deep Learning Model Applied to Optical Image Target Detection and Recognition for the Identification of Underwater Biostructures
by Huilin Ge, Yuewei Dai, Zhiyu Zhu and Runbang Liu
Machines 2022, 10(9), 809; https://doi.org/10.3390/machines10090809 - 15 Sep 2022
Cited by 7 | Viewed by 1894
Abstract
Objective: We propose a deep-learning-based underwater target detection system that can effectively solve the problem of underwater optical image target detection and recognition. Methods: In this paper, based on the depth of the underwater optical image target detection and recognition and using a [...] Read more.
Objective: We propose a deep-learning-based underwater target detection system that can effectively solve the problem of underwater optical image target detection and recognition. Methods: In this paper, based on the depth of the underwater optical image target detection and recognition and using a learning model, we put forward corresponding solutions using the concept of style migration solutions, such as training samples. A lack of variability and poor generalization of practical applications presents a challenge for underwater object identification. The UW_YOLOv3 lightweight model was proposed to solve the problems of calculating energy consumption and storage resource limitations in underwater application scenarios. The detection and recognition module, based on deep learning, can deal with the degradation process of underwater imaging by embedding an image enhancement module into the detection and recognition module for the joint tuning and transferring of knowledge. Results: The detection accuracy of the UW_YOLOv3 model designed in this paper outperformed the lightweight algorithm YOLOV3-TINY by 7.9% at the same image scale input. Compared with other large algorithms, the detection accuracy was lower, but the detection speed was much higher. Compared with the SSD algorithm, the detection accuracy was only 4.7 lower; the speed was 40.9 FPS higher; and the rate was nearly 16 times higher than Faster R-CNN. When the input scale was 224, although part of the accuracy was lost, the detection speed doubled, reaching 156.9 FPS. Conclusion: Based on our framework, the problem of underwater optical image target detection and recognition can be effectively solved. Relevant studies have not only enriched the theory of target detection and glory, but have also provided optical glasses with a clear vision for appropriate underwater application systems. Full article
(This article belongs to the Topic Artificial Intelligence in Smart Industrial Diagnostics and Manufacturing)
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8 pages, 958 KiB  
Article
Automating the Optimal Selection Process of Subassembly Sections of a Modular Spreader Beam Used in Lifting Operations
by Tom Wheatley, Perk Lin Chong, Hossein Habibi and Wan Djawad
Machines 2022, 10(9), 808; https://doi.org/10.3390/machines10090808 - 15 Sep 2022
Viewed by 1705
Abstract
Spreader beams used in lifting operations undergo a purely compressive load to spread apart the ends of a sling which enables large payloads to be lifted from a single point, such as a crane hook, without damage. A modular spreader beam can be [...] Read more.
Spreader beams used in lifting operations undergo a purely compressive load to spread apart the ends of a sling which enables large payloads to be lifted from a single point, such as a crane hook, without damage. A modular spreader beam can be made using subcomponents of different standard sizes to create a spreader beam of any length, making them more versatile and cost-effective than non-modular spreader beams. However, while the manual calculation and selection of an optimum number of subsections for a single beam is straightforward, the process for the multiple range of spreader beam is very challenging and is labour-intensive in a lifting company. The main aim of this study was to develop an automated system for determining the optimal configuration of the modular spreader beam which leads to increasing the efficiency of the lifting company through saving the associated labour and time costs. The automated system is underpinned by designing an algorithm based on a dynamic programming optimisation search to test every possible configuration and return the optimal configuration. Hence, the main novelty in this study is the development of a computer-based system to automate the selection process of the modular beam’s subsections, which generates an optimal package immediately to create different lengths with the fewest sections needed for a lifting operation. Eventually, the process of generating quotation for clients can be significantly accelerated while the risk of human errors can be also eliminated. Full article
(This article belongs to the Section Automation and Control Systems)
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15 pages, 7581 KiB  
Article
Modelling and Experiment of an Adjustable Device Combining an Inerter and a Damper
by Xiaoliang Zhang, Weian Zhu and Jiamei Nie
Machines 2022, 10(9), 807; https://doi.org/10.3390/machines10090807 - 14 Sep 2022
Cited by 1 | Viewed by 1283
Abstract
In an effort to solve the issue of unadjustable damping of skyhook inertance suspension, a new adjustable device combining an inerter and a damper that aims to simultaneously adjust the inertance and damping was proposed. This article proposes a near practical mathematical model [...] Read more.
In an effort to solve the issue of unadjustable damping of skyhook inertance suspension, a new adjustable device combining an inerter and a damper that aims to simultaneously adjust the inertance and damping was proposed. This article proposes a near practical mathematical model of such an adjustable device, and the model is found to be equivalent to a parallel connection of an adjustable inerter and damper. A prototype of such a device is made, and its damping and inertial forces are separated through quasi-static and dynamic mechanical character tests. The validity of the theoretical models is verified through a comparison between the test and simulation results of the mechanical character with a maximum error of 4.96% for the damping model and 6.28% for the inertial model, which lays the foundation for subsequent studies on adjustable regular patterns of inertance and damping as well as applications in semi-active ISD suspensions. In addition, the device simplifies an inerter and a damper into one device and reduces the layout space and cost, which is of great engineering application value. Full article
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18 pages, 16665 KiB  
Article
Design and Optimization of the Surface Texture at the Hydrostatic Bearing and the Spindle for High Precision Machining
by Youyun Shang, Kai Cheng, Hui Ding and Shijin Chen
Machines 2022, 10(9), 806; https://doi.org/10.3390/machines10090806 - 13 Sep 2022
Cited by 5 | Viewed by 1715
Abstract
Hydrostatic bearing spindles are widely applied in high precision grinding and turning machines due to their good dynamic stability and rotational accuracy. However, under the condition of high-speed rotations, the heat generated by the friction of the oil film will cause the shear [...] Read more.
Hydrostatic bearing spindles are widely applied in high precision grinding and turning machines due to their good dynamic stability and rotational accuracy. However, under the condition of high-speed rotations, the heat generated by the friction of the oil film will cause the shear thinning effect. It not only reduces the rotation accuracy of the spindle but also reduces the service life of the spindle. The surface texture structure and configuration between the planes play the role of homogenizing oil film temperature and preventing the bearing surface wear caused by excessive concentration of temperature, which can change the relative motion from the inside of the oil film and thus improve the performance of the hydrostatic spindle more effectively. In this paper, the influence of the surface texture shape and height on the thrust bearing performance of the hydrostatic spindle is systematically investigated by comparative analysis. The CFD simulations are developed to analyze the computational results based on the theory of viscosity-temperature characteristics. The results show that when the height of the surface structure is 1 ~ 2 times the oil film thickness, the spindle bearing performance is the best. The average temperature in the bearing region is the lowest and the accuracy of the simulations was verified by experimental results. Full article
(This article belongs to the Special Issue High Precision Abrasive Machining: Machines, Processes and Systems)
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18 pages, 8990 KiB  
Article
Dynamic Analysis of Gear Rattling of a Certain Type of Dual-Clutch Transmission
by Dong Guo, Qinfeng Ning, Shuaishuai Ge, Yi Zhou and Ruitian Luo
Machines 2022, 10(9), 805; https://doi.org/10.3390/machines10090805 - 12 Sep 2022
Cited by 2 | Viewed by 1886
Abstract
In order to accurately explore the transmission rattling phenomenon and the influence of different factors on the dynamic characteristics of the gear rattling of the dual-clutch transmission under the condition of preselected gears, this paper establishes the gear rattling dynamics model of the [...] Read more.
In order to accurately explore the transmission rattling phenomenon and the influence of different factors on the dynamic characteristics of the gear rattling of the dual-clutch transmission under the condition of preselected gears, this paper establishes the gear rattling dynamics model of the transmission with the 1st gear without preselection and the preselected 4th gear, respectively; The model takes into account factors such as time-varying mesh stiffness, mesh damping, nonlinear oil film force, nonlinear backlash, and the drag torque generated by the clutch in the unengaged state. In addition, the feasibility of the dynamic model was verified by the bench test. On this basis, we took the gear meshing power and system power loss as quantitative indexes to analyze the influence of the preselected gear state and different parameters on the rattle vibration of the transmission. The results show that the pre-selected gear will not have a significant effect on the gears that have been rattled in the non-pre-selected state, and the torque fluctuation of the non-power flow shaft is aggravated by the influence of the transmission power flow branch and transmission ratio at different levels, which makes the overall rattling strength increase. In order to improve the transmission efficiency of the gear, the torque fluctuation of the input end of the system should be reduced as much as possible, and a larger lubricant viscosity can be appropriately selected, the inertia of the empty gear can be properly reduced, and the tooth clearance can be relaxed for selection. Full article
(This article belongs to the Special Issue Noise and Vibration Control in Dynamic Systems)
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26 pages, 6334 KiB  
Article
Dynamic Tangential Contact Stiffness and Damping Model of the Solid–Liquid Interface
by Lixia Peng, Zhiqiang Gao, Zhaoyang Ban, Feng Gao and Weiping Fu
Machines 2022, 10(9), 804; https://doi.org/10.3390/machines10090804 - 12 Sep 2022
Cited by 4 | Viewed by 2041
Abstract
In order to establish the tangential contact stiffness and damping model of the solid–liquid interface by tangential exciting vibration force under mixed lubrication, the finite difference method was firstly used to solve the average flow equation considering the effect of roughness on the [...] Read more.
In order to establish the tangential contact stiffness and damping model of the solid–liquid interface by tangential exciting vibration force under mixed lubrication, the finite difference method was firstly used to solve the average flow equation considering the effect of roughness on the lubrication effect, and the bearing capacity, shear force, and friction coefficient of the oil film were obtained, and thereby the dynamic tangential contact stiffness and damping of the oil film under tangential harmonic excitation were calculated. Then, according to the relationship between the normal deformation and the load of the solid contact microconvex body in the elastic/elastic–plastic/plastic deformation stage, integrating the tangential stick–slip theory, considering the effect of fluid lubrication on the solid contact friction coefficient, and tangential dynamic excitation, the tangential contact stiffness and damping of the microconvex body in three deformation stages were calculated. Furthermore, the dynamic tangential contact stiffness and damping of the solid–liquid interface were obtained by summing the solid surface contact part and the solid–liquid contact part in parallel according to the assumption of microconvex Gaussian distribution. Finally, through simulation analysis and experiments, the variation of the tangential dynamic contact stiffness and damping of the solid–liquid interface with normal load, tangential exciting frequency, and displacement amplitude was revealed and verified. Full article
(This article belongs to the Section Friction and Tribology)
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19 pages, 6871 KiB  
Article
Energy Harvesting Performance of a Novel Nonlinear Quad-Stable Piezoelectric Energy Harvester with Only One External Magnet
by Shuailing Sun, Yonggang Leng, Sunghoon Hur, Fei Sun, Xukun Su, Hyun-Cheol Song and Chong-Yun Kang
Machines 2022, 10(9), 803; https://doi.org/10.3390/machines10090803 - 11 Sep 2022
Cited by 6 | Viewed by 1883
Abstract
Nonlinear multi-stable piezoelectric energy harvesters show broadband frequency spectra and excellent energy harvesting performance, owing to their high output power related to inter-well transitions. However, existing quad-stable piezoelectric energy harvesters contain too many structural parameters, which makes the systems clumsy, and increases the [...] Read more.
Nonlinear multi-stable piezoelectric energy harvesters show broadband frequency spectra and excellent energy harvesting performance, owing to their high output power related to inter-well transitions. However, existing quad-stable piezoelectric energy harvesters contain too many structural parameters, which makes the systems clumsy, and increases the difficulties of dynamic analysis and structural optimization. Herein, a nonlinear quad-stable piezoelectric energy harvester, with only one external magnet, is proposed based on the magnetic force characteristics between a ring magnet and a rectangular magnet. Under selected structural parameters, as the magnet spacing increases, the stability characteristic of the harvester changes from quad-stability to bi-stability, and then to mono-stability. The transformation of the stability characteristic results from the changes in the variation rate of the vertical magnetic force. Subsequently, under the filtered Gaussian white noise within the frequency range of 0–120 Hz, the energy harvesting performance of the harvester is simulated by the classic fourth-order Runge-Kutta method. Simulation results show that the performance of the harvester under the quad-stable structural parameters is better than that under the bi-stable structural parameters, independent of whether the excitation acceleration is small or large. This result is related to the potential well characteristics under the quad-stable and bi-stable structural parameters. More specifically, the potential well depths under the quad-stable and bi-stable structural parameters are almost the same, but the distance between the two outer potential wells under the quad-stable structural parameters is larger than that under the bi-stable structural parameters. Finally, a fabricated prototype is used to measure the experimental performance of the harvester. The experimental data and the estimated data share the same trend. This study provides a new conception and technical method for the design, optimization, and application of quad-stable piezoelectric energy harvesters. Full article
(This article belongs to the Special Issue New Advances in Energy Harvesters)
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14 pages, 3508 KiB  
Article
Research on Adaptive Control of Grinding Force for Carbide Indexable Inserts Grinding Process Based on Spindle Motor Power
by Peng Chen, Xianglei Zhang, Ming Feng, Sisi Li, Xiaoming Pan and Wei Feng
Machines 2022, 10(9), 802; https://doi.org/10.3390/machines10090802 - 11 Sep 2022
Cited by 2 | Viewed by 1799
Abstract
The grinding force is the most sensitive physical measure of reaction loads in the grinding process. To enhance surface quality and assure high efficiency and stability of the grinding process, it is essential to accomplish adaptive control of the grinding force. This paper [...] Read more.
The grinding force is the most sensitive physical measure of reaction loads in the grinding process. To enhance surface quality and assure high efficiency and stability of the grinding process, it is essential to accomplish adaptive control of the grinding force. This paper suggests a grinding force adaptive control system based on spindle motor power feedback, considering the process–machine interaction. The spindle motor power is utilized as a proxy for the grinding force because of the mapping relationship between the two variables. The machine tool’s feed rate is automatically modified to achieve adaptive control of the grinding force, after assessing the discrepancy between the collected spindle motor power and the preset power. Finally, a cemented carbide tool grinding experiment was performed on a 2MZK7150 CNC tool grinder. During the experiment, the grinding force was precisely controlled between 80 and 100 N, ensuring machining quality and increasing machining efficiency. The experimental results show that the adaptive control system can meet the high-efficiency and high-quality machining requirements of cemented carbide rotary blades. Full article
(This article belongs to the Special Issue High Precision Abrasive Machining: Machines, Processes and Systems)
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30 pages, 61268 KiB  
Article
A Novel Numerical Method for Theoretical Tire Model Simulation
by Qianjin Liu, Dang Lu, Yao Ma and Danhua Xia
Machines 2022, 10(9), 801; https://doi.org/10.3390/machines10090801 - 11 Sep 2022
Cited by 1 | Viewed by 1925
Abstract
Theoretical tire models are often used in tire dynamics analysis and tire design. In the past, scholars have carried out a lot of research on theoretical model modeling; however, little progress has been made on its solution. This paper focuses on the numerical [...] Read more.
Theoretical tire models are often used in tire dynamics analysis and tire design. In the past, scholars have carried out a lot of research on theoretical model modeling; however, little progress has been made on its solution. This paper focuses on the numerical solution of the theoretical model. New force and moment calculation matrix equations are constructed, and different iterative methods are compared. The results show that the modified Richardson iteration method proposed in this paper has the best convergence-stability in the steady and unsteady state calculation, which mathematically solves the problem of nonconvergence of discrete theoretical models in the published reference. A novel discrete method for solving the total deformation of tires is established based on the Euler method. The unsteady characteristics of tire models are only related to the path frequency without changing its parameters, so the unsteady state ability of the tire model can be judged based on this condition. It shows that the method in the references have significant differences at different speeds with the same path frequency under turn slip or load variations input, but the method proposed in this paper has good results. Full article
(This article belongs to the Section Vehicle Engineering)
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18 pages, 7962 KiB  
Article
An Alpha/Beta Radiation Mapping Method Using Simultaneous Localization and Mapping for Nuclear Power Plants
by Xin Liu, Lan Cheng, Yapeng Yang, Gaowei Yan, Xinying Xu and Zhe Zhang
Machines 2022, 10(9), 800; https://doi.org/10.3390/machines10090800 - 11 Sep 2022
Cited by 3 | Viewed by 1715
Abstract
Nuclear safety has always been a focal point in the field of nuclear applications. Mobile robots carrying specific sensors for nuclear-radiation detection have become an alternative to manual detection. This work presents an autonomous α/β radiation mapping framework, using a mobile robot carrying [...] Read more.
Nuclear safety has always been a focal point in the field of nuclear applications. Mobile robots carrying specific sensors for nuclear-radiation detection have become an alternative to manual detection. This work presents an autonomous α/β radiation mapping framework, using a mobile robot carrying a light detection and ranging (LiDAR) and a nuclear-radiation-detection sensor. The method employs simultaneous localization and mapping (SLAM) techniques and radiation-detection sensors. Cartographer is adopted as a demonstration example to map the unknown environment. Radiation data are obtained through the radiation detection sensor and projected onto the environment map after coordinate alignment. The color-coded radiation map is shown on the environment map according to the dose rate. The simulation and real-environment experiments in a robot-operating system (ROS) validate the effectiveness of the proposed method in different radiation scenarios for both indoor and outdoor environments. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
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11 pages, 1145 KiB  
Communication
A Vehicle Comparison and Re-Identification System Based on Residual Network
by Weifeng Yin, Yusong Min and Junyong Zhai
Machines 2022, 10(9), 799; https://doi.org/10.3390/machines10090799 - 10 Sep 2022
Viewed by 1230
Abstract
In the highway intelligent monitoring system, it is difficult to find the target vehicle through millions of pictures because of the presence of fake-licensed vehicles. In order to solve this problem, a vehicle comparison and re-identification (Re-ID) system is built in this paper. [...] Read more.
In the highway intelligent monitoring system, it is difficult to find the target vehicle through millions of pictures because of the presence of fake-licensed vehicles. In order to solve this problem, a vehicle comparison and re-identification (Re-ID) system is built in this paper. By introducing Circle loss and Generalized-Mean(GeM) pooling, vehicle feature extraction and storage, vehicle comparison and vehicle search can be realized. Experimental results show that the proposed algorithm reaches 95.79% of the mean Average Precision (mAP) on the vehicle search task, which meets the requirements of practical applications. Full article
(This article belongs to the Section Vehicle Engineering)
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20 pages, 9953 KiB  
Article
Hydrodynamic Characteristic-Based Adaptive Model Predictive Control for the Spherical Underwater Robot under Ocean Current Disturbance
by Ao Li, Shuxiang Guo, Meng Liu and He Yin
Machines 2022, 10(9), 798; https://doi.org/10.3390/machines10090798 - 10 Sep 2022
Cited by 5 | Viewed by 1604
Abstract
In the navigation of underwater robots, large ocean current disturbance often causes significant tracking errors. To better resist ocean current disturbance, the hydrodynamic characteristics of the spherical underwater robot are studied, and a model predictive control strategy based on adaptive model parameters is [...] Read more.
In the navigation of underwater robots, large ocean current disturbance often causes significant tracking errors. To better resist ocean current disturbance, the hydrodynamic characteristics of the spherical underwater robot are studied, and a model predictive control strategy based on adaptive model parameters is proposed, according to these characteristics. Firstly, the hydrodynamic characteristics of the robot under static water and constant flow disturbance were obtained and analyzed by the computational fluid dynamics method. Then, the dynamic models of the robot under different disturbances could be calculated from the data obtained, based on the least square method. Finally, an adaptive model predictive control (AMPC) strategy, with an ocean current observer, was designed, based on the dynamic models. When the current disturbance velocity was twice the robot velocity, the proposed strategy reduced the tracking error by 39% and 42% in X and Y directions, respectively. In addition, the hydrodynamic characteristics were verified by experiments. Full article
(This article belongs to the Special Issue Advances in Underwater Robot Technology)
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16 pages, 4351 KiB  
Article
Reliability-Based Robust Design Optimization for Maximizing the Output Torque of Brushless Direct Current (BLDC) Motors Considering Manufacturing Uncertainty
by Kyunghun Jeon, Donghyeon Yoo, Jongjin Park, Ki-Deok Lee, Jeong-Jong Lee and Chang-Wan Kim
Machines 2022, 10(9), 797; https://doi.org/10.3390/machines10090797 - 10 Sep 2022
Cited by 6 | Viewed by 1830
Abstract
In recent years, the deterministic design optimization method has been widely used to improve the output performance of brushless direct current (BLDC) motors. However, it does not contribute to reducing the failure rate and performance variation of products because it cannot determine the [...] Read more.
In recent years, the deterministic design optimization method has been widely used to improve the output performance of brushless direct current (BLDC) motors. However, it does not contribute to reducing the failure rate and performance variation of products because it cannot determine the manufacturing uncertainty. In this study, we proposed reliability-based robust design optimization to improve the output torque of a BLDC motor while reducing the failure rate and performance variation. We calculated the output torque and vibration response of the BLDC motor using the electromagnetic–structural coupled analysis. We selected the tooth thickness, slot opening width, slot radius, slot depth, tooth width, magnet thickness, and magnet length as the design variables related to the shape of the stator and rotor that affect the output torque. We considered the distribution of design variables with manufacturing tolerances. We performed a reliability analysis of the BLDC motor considering the distribution of design variables with manufacturing tolerances. Using the reliability analysis results, we performed reliability-based robust design optimization (RBRDO) to maximize the output torque; consequently, the output torque increased by 8.8% compared to the initial BLDC motor, the standard deviation in output performance decreased by 46.9% with improved robustness, and the failure rate decreased by 99.2% with enhanced reliability. The proposed reliability-based robust design optimization is considered to be useful in the actual product design field because it can evaluate both the reliability and robustness of the product and improve its performance in the design stage. Full article
(This article belongs to the Special Issue Reliability of Mechatronic Systems and Machine Elements: Testing and Validation)
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23 pages, 9042 KiB  
Article
The Rail Surface Defects Recognition via Operating Service Rail Vehicle Vibrations
by Shubin Zheng, Qianwen Zhong, Xieqi Chen, Lele Peng and Guiyan Cui
Machines 2022, 10(9), 796; https://doi.org/10.3390/machines10090796 - 10 Sep 2022
Cited by 4 | Viewed by 1423
Abstract
Rail surface defects will not only bring wheel rail noise during train operation, but also cause corresponding accidents. Most of the existing detection methods are manual detection, which is time-consuming, laborious, inefficient, and subjective. With the development of technology, automatic detection replaces manual [...] Read more.
Rail surface defects will not only bring wheel rail noise during train operation, but also cause corresponding accidents. Most of the existing detection methods are manual detection, which is time-consuming, laborious, inefficient, and subjective. With the development of technology, automatic detection replaces manual detection, which reduces manual labor, improves efficiency, and objectively evaluates the surface state of rails, which is in line with the purpose of modern intelligent production. The automatic detection of a single sensor is usually not enough to complete the recognition, but multiple sensors need to be additionally installed and refitted on the service vehicle, which creates difficulty for on-site test conditions. Therefore, in order to overcome these shortages and to adapt to the actual vibration characteristics of service vehicles, a rail surface defect recognition method based on optimized VMD gray image coding and DCNN is proposed in this paper. Firstly, the optimization method of VMD mode number based on the maximum envelope kurtosis is proposed. The VMD after parameter optimization is used to decompose the four-channel axle box vibration signal, and the component with the largest correlation coefficient between each order eigenmode component and the original signal is extracted. Secondly, the filtered IMF components are arranged in sequence and encoded into grayscale images. Finally, the DCNN structure is designed, and the training set is input into the network for training, and the test set verifies the effectiveness of the network and realizes the recognition of rail surface defects. The test accuracy of railway data set measured on the serviced vehicle is 99.75%, and the results show that this method can accurately identify the category of rail surface defects. After adding Gaussian noise to the original signal, the test accuracy reaches 99.20%, which proves that the method has good generalization ability and anti-noise performance. Additionally, this method can ensure the safe operation of vehicles without adding new equipment, which reduces operation costs and improves the intelligent operation and maintenance of rails. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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21 pages, 10282 KiB  
Article
Design and Performance Evaluation of a Novel Slave System for Endovascular Tele-Surgery
by Chaochao Shi, Shuxiang Guo and Masahiko Kawanishi
Machines 2022, 10(9), 795; https://doi.org/10.3390/machines10090795 - 09 Sep 2022
Cited by 4 | Viewed by 2500
Abstract
Vascular interventional robots have attracted growing attention in recent years. However, current vascular interventional robot systems generally lack force feedback and cannot quickly clamp the catheter/guidewire. The structure of slave systems is unstable and the power transmission is imprecise, increasing the system’s safety [...] Read more.
Vascular interventional robots have attracted growing attention in recent years. However, current vascular interventional robot systems generally lack force feedback and cannot quickly clamp the catheter/guidewire. The structure of slave systems is unstable and the power transmission is imprecise, increasing the system’s safety hazards. Vascular intervention robots generally do not follow traditional surgeons’ operation habits and, thus, it is not easy for them to understand and learn how to operate. Therefore, a novel vascular intervention system is proposed. The slave system can quickly clamp the catheter/guidewire, is compatible with various standard catheter/guidewire sizes, has precise power transmission, and has a stable structure. The surface of the catheter/guidewire is clamped without damage. Whether it is on the master side or the slave side, it follows the habits of traditional operators to a great extent. The results show that the measurement accuracy of the axial force meets the requirements of robot-assisted surgery and the system can track the designed position of the catheter/guidewire in real time. This study makes a certain contribution to the development of master–slave systems for endovascular tele-surgery. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
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18 pages, 5523 KiB  
Article
Using Multivariate Quality Statistic for Maintenance Decision Support in a Bearing Ring Grinder
by Muhammad Ahmer, Fredrik Sandin, Pär Marklund, Martin Gustafsson and Kim Berglund
Machines 2022, 10(9), 794; https://doi.org/10.3390/machines10090794 - 09 Sep 2022
Cited by 1 | Viewed by 1716
Abstract
Grinding processes’ stochastic nature poses a challenge in predicting the quality of the resulting surfaces. Post-production measurements for form, surface roughness, and circumferential waviness are commonly performed due to infeasibility in measuring all quality parameters during the grinding operation. Therefore, it is challenging [...] Read more.
Grinding processes’ stochastic nature poses a challenge in predicting the quality of the resulting surfaces. Post-production measurements for form, surface roughness, and circumferential waviness are commonly performed due to infeasibility in measuring all quality parameters during the grinding operation. Therefore, it is challenging to diagnose the root cause of quality deviations in real-time resulting from variations in the machine’s operating condition. This paper introduces a novel approach to predict the overall quality of the individual parts. The grinder is equipped with sensors to implement condition-based maintenance and is induced with five frequently occurring failure conditions for the experimental test runs. The crucial quality parameters are measured for the produced parts. Fuzzy c-means (FCM) and Hotelling’s T-squared (T2) have been evaluated to generate quality labels from the multi-variate quality data. Benchmarked random forest regression models are trained using fault diagnosis feature set and quality labels. Quality labels from the T2 statistic of quality parameters are preferred over FCM approach for their repeatability. The model, trained from T2 labels achieves more than 94% accuracy when compared to the measured ring disposition. The predicted overall quality using the sensors’ feature set is compared against the threshold to reach a trustworthy maintenance decision. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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