Machines

23 pages, 1808 KiB

Open AccessArticle

Cyber-Physical Scheduling System for Multiobjective Scheduling Optimization of a Suspension Chain Workshop Using the Improved Non-Dominated Sorting Genetic Algorithm II

by Wenbin Zhao, Junhan Hu, Jiansha Lu and Wenzhu Zhang

Machines 2024, 12(9), 666; https://doi.org/10.3390/machines12090666 - 23 Sep 2024

Viewed by 620

Abstract

Cyber-Physical Systems (CPSs) offer significant potential to address the evolving demands of industrial development. In the Industry 4.0 era, a framework integrating sensing, data exchange, numerical analysis, and real-time feedback is essential for meeting modern industrial needs. However, implementing this integration presents challenges [...] Read more.

Cyber-Physical Systems (CPSs) offer significant potential to address the evolving demands of industrial development. In the Industry 4.0 era, a framework integrating sensing, data exchange, numerical analysis, and real-time feedback is essential for meeting modern industrial needs. However, implementing this integration presents challenges across multiple domains, particularly in digital analysis, information sensing, and data exchange during corporate transformation. Companies yet to undergo transformation face distinct challenges, including the risks and trial-and-error costs of adopting new technologies. This study focuses on a heavy-duty workpiece processing factory, with a specific emphasis on the painting process. The complexity of this process frequently results in congestion, which is approached as a multi-objective, multi-constraint optimization problem. This paper proposes the Improved Non-dominated Sorting Genetic Algorithm II (INSGA-II) to address the requirements of multi-objective optimization. The proposed approach uses multi-chromosome structures, listeners, and recursive backtracking initialization to optimize the search for solutions under constraints. This enables the factory to automatically streamline production lines based on workpiece processing sequences, leading to increased efficiency. Additionally, a CPS framework focused on simulation modeling has been designed. First, the INSGA-II algorithm processes order data to generate production schedules. Next, the data transmission formats and input-output interfaces are designed. Then, a simulation model is built using the algorithm’s results. These components collectively form the CPS framework for this study. The proposed method offers an automated digital solution through the algorithm, enabling verification of its feasibility via the simulation model. As a result, it significantly enhances decision-making speed, reliability, and equipment utilization. Full article

(This article belongs to the Special Issue Digital Twin-Driven Smart Production, Logistics, and Supply Chains)

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19 pages, 3903 KiB

Open AccessArticle

Pick and Place Control of a 3-DOF Robot Manipulator Based on Image and Pattern Recognition

by Samuel Kariuki, Eric Wanjau, Ian Muchiri, Joseph Muguro, Waweru Njeri and Minoru Sasaki

Machines 2024, 12(9), 665; https://doi.org/10.3390/machines12090665 - 23 Sep 2024

Viewed by 889

Abstract

Board games like chess serve as an excellent testbed for human–robot interactions, where advancements can lead to broader human–robot cooperation systems. This paper presents a chess-playing robotic system to demonstrate controlled pick and place operations using a 3-DoF manipulator with image and speech [...] Read more.

Board games like chess serve as an excellent testbed for human–robot interactions, where advancements can lead to broader human–robot cooperation systems. This paper presents a chess-playing robotic system to demonstrate controlled pick and place operations using a 3-DoF manipulator with image and speech recognition. The system identifies chessboard square coordinates through image processing and centroid detection before mapping them onto the physical board. User voice input is processed and transcribed into a string from which the system extracts the current and destination locations of a chess piece with a word error rate of 8.64%. Using an inverse-kinematics algorithm, the system calculates the joint angles needed to position the end effector at the desired coordinates actuating the robot. The developed system was evaluated experimentally on the 3-DoF manipulator with a voice command used to direct the robot movement in grasping a chess piece. Consideration was made involving both the own pieces as well as capturing the opponent’s pieces and moving the captured piece outside the board workspace. Full article

(This article belongs to the Special Issue Advances in Robotic Manipulation through Artificial Intelligence and Innovative Gripping Concepts)

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17 pages, 4409 KiB

Open AccessArticle

Wavelet-Based Computational Intelligence for Real-Time Anomaly Detection and Fault Isolation in Embedded Systems

by Jesus Pacheco, Victor H. Benitez, Guillermo Pérez and Agustín Brau

Machines 2024, 12(9), 664; https://doi.org/10.3390/machines12090664 - 22 Sep 2024

Viewed by 1568

Abstract

In today’s technologically advanced landscape, sensors feed critical data for accurate decision-making and actions. Ensuring the integrity and reliability of sensor data is paramount to system performance and security. This paper introduces an innovative approach utilizing discrete wavelet transforms (DWT) embedded within microcontrollers [...] Read more.

In today’s technologically advanced landscape, sensors feed critical data for accurate decision-making and actions. Ensuring the integrity and reliability of sensor data is paramount to system performance and security. This paper introduces an innovative approach utilizing discrete wavelet transforms (DWT) embedded within microcontrollers to scrutinize sensor data meticulously. Our methodology aims to detect and isolate malfunctions, misuse, or any anomalies before they permeate the system, potentially causing widespread disruption. By leveraging the power of wavelet-based analysis, we embed computational intelligence directly into the microcontrollers, enabling them to monitor and validate their outputs in real-time. This proactive anomaly detection framework is designed to distinguish between normal and aberrant sensor behaviors, thereby safeguarding the system from erroneous data propagation. Our approach significantly enhances the reliability of embedded systems, providing a robust defense against false data injection attacks and contributing to overall cybersecurity. Full article

(This article belongs to the Special Issue Computational Intelligence for Fault Detection and Classification)

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19 pages, 4909 KiB

Open AccessArticle

An Automatic Vehicle Navigation System Based on Filters Integrating Inertial Navigation and Global Positioning Systems

by Haizhu Xu, Duanyang Geng, Zhixian Fan, Dexi Wu and Meizhou Chen

Machines 2024, 12(9), 663; https://doi.org/10.3390/machines12090663 - 21 Sep 2024

Viewed by 3707

Abstract

The key technologies for advanced autonomous vehicles include those relating to perception, decision making, and execution. Path-tracking control in autonomous vehicles is heavily dependent on their positioning system. Therefore, the development of low-cost and reliable positioning systems is crucial to improving perception and [...] Read more.

The key technologies for advanced autonomous vehicles include those relating to perception, decision making, and execution. Path-tracking control in autonomous vehicles is heavily dependent on their positioning system. Therefore, the development of low-cost and reliable positioning systems is crucial to improving perception and decision-making technologies for autonomous vehicles. Although the accuracy of the global positioning system (GPS) is extremely high, it is vulnerable to interference. Further, despite the low positioning accuracy of inertial navigation systems (INSs), their robustness is notably high. Therefore, an integrated navigation information method based on the Adaptive Particle Filter and the Iterative Kalman Filter (APF-IKF) was developed in this study. Firstly, an integrated navigation system model was established. Then, the IKF was adopted to estimate the speed, latitude and longitude errors of the INS. Thirdly, the newest estimated error results were introduced into the APF to optimize the distribution function, and the particle quality was improved. In this process, the APF can filter non-Gaussian noise, preliminarily estimate the error, optimize the result with the IKF and correct the output information of the INS with the final estimated error. Finally, by using differential GPS positioning as the benchmark, we built a real-vehicle test platform with a low-cost and low-precision GPS and inertial units and carried out a series of real-vehicle tests. The experimental results show that compared with the traditional KF method, APF-IKF can significantly improve the positioning accuracy and robustness of the system. Full article

(This article belongs to the Special Issue Modeling, Estimation, Control, and Decision for Intelligent Vehicles)

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17 pages, 13481 KiB

Open AccessArticle

Detection of Broken Bars in Induction Motors Operating with Closed-Loop Speed Control

by Francesca Muzio, Lorenzo Mantione, Tomas Garcia-Calva, Lucia Frosini and Daniel Morinigo-Sotelo

Machines 2024, 12(9), 662; https://doi.org/10.3390/machines12090662 - 21 Sep 2024

Cited by 1 | Viewed by 570

Abstract

Rotor bar breakage in induction motors is often detected by analysing the signatures in the stator current. However, due to the alteration of the current spectrum, traditional methods may fail when inverter-fed motors operate with closed-loop control using a cascade structure to regulate [...] Read more.

Rotor bar breakage in induction motors is often detected by analysing the signatures in the stator current. However, due to the alteration of the current spectrum, traditional methods may fail when inverter-fed motors operate with closed-loop control using a cascade structure to regulate the speed. In this paper, the potential of zero-sequence voltage analysis to detect this fault is investigated, and a new index to quantify the severity of the fault based on this signal is proposed. Signals from motors operating under different control strategies and signals from motors powered from the mains are considered to verify the robustness of the proposed fault severity index. As a result, in all the analysed conditions the value of the proposed index for the healthy motor is found to be approximately 0.010, while for the faulty machine it is between 0.110 and 0.252. Full article

(This article belongs to the Section Electrical Machines and Drives)

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21 pages, 7085 KiB

Open AccessArticle

Creating the Slider Tester Repair Recommendation System to Enhance the Repair Step by Using Machine Learning

by Rattaphong Udomsup, Suphatchakan Nuchkum, Jiraphon Srisertpol, Natthapon Donjaroennon and Uthen Leeton

Machines 2024, 12(9), 661; https://doi.org/10.3390/machines12090661 - 21 Sep 2024

Viewed by 527

Abstract

This project aims to develop a recommendation system to mitigate looping issues in HDD slider testing using the Amber testing machine (Machine A). Components simulating the HDD often fail and require repair before re-testing. However, post-repair, there is a 34% probability that the [...] Read more.

This project aims to develop a recommendation system to mitigate looping issues in HDD slider testing using the Amber testing machine (Machine A). Components simulating the HDD often fail and require repair before re-testing. However, post-repair, there is a 34% probability that the component (referred to as Product A) will experience looping, characterized by repeated failures with error code A. This recurring issue significantly hampers testing efficiency by reducing the number of successful slider tests. To address this challenge, we propose a dual-approach recommendation system that provides technicians with actionable insights to minimize the occurrence of looping. For previously analyzed components, a collaborative filtering technique utilizing implicit ratings is employed to generate recommendations. For new components, for which prior data are unavailable, a cosine similarity approach is applied to suggest optimal actions. An automatic training system is implemented to retrain the model as new data become available, ensuring that the recommendation system remains robust and effective over time. The proposed system is expected to offer precise guidance to technicians, thereby improving the overall efficiency of the testing process by reducing the frequency of looping issues. This work represents a significant advancement in enhancing operational reliability and productivity in HDD slider testing. Full article

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

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22 pages, 9503 KiB

Open AccessArticle

Experimental Determination and Simulation Validation: Johnson–Cook Model Parameters and Grinding Simulation of 06Cr18Ni11Ti Stainless Steel Welds

by Shengfang Zhang, Zhiyi Leng, Qiang Duan, Hongtao Gu, Mingjie Lu, Ziguang Wang and Yu Liu

Machines 2024, 12(9), 660; https://doi.org/10.3390/machines12090660 - 21 Sep 2024

Viewed by 669

Abstract

Hydrogen permeation resistance in the welded region of 06Cr18Ni11Ti steel is relatively weak due to surface defects, which need high integrity surface machining. The parameters of the welding material for 06Cr18Ni11Ti steel are currently unavailable, which causes some inconvenience for simulation studies. To [...] Read more.

Hydrogen permeation resistance in the welded region of 06Cr18Ni11Ti steel is relatively weak due to surface defects, which need high integrity surface machining. The parameters of the welding material for 06Cr18Ni11Ti steel are currently unavailable, which causes some inconvenience for simulation studies. To fill the lack of 06Cr18Ni11Ti steel weld material parameters in the relevant literature at the present stage, the quasi-static tensile test at different strain rates and notch specimen tensile tests were conducted in this paper and determined the Johnson–Cook (J-C) constitutive model parameters and Johnson–Cook failure model parameters. Subsequently, a multi-grain grinding simulation model was built based on W-M fractal dimension theory by using the determined material parameters. The influence of processing parameters on grinding heat was analyzed. Grinding experiments were conducted to analyze the influence of processing parameters on grinding heat and grinding force. By comparing the simulation and experimental results, it is revealed that the average error is 9.37%, indicating relatively small discrepancy. It is demonstrated that the grinding simulation model built in this paper could efficiently simulate the grinding process, and the determined weld material parameters of 06Cr18Ni11Ti steel have been verified to possess high accuracy and reliability. Full article

(This article belongs to the Section Advanced Manufacturing)

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23 pages, 1613 KiB

Open AccessArticle

Classification Scheme for the Three-Point Dubins Problem

by Daniela De Palma and Gianfranco Parlangeli

Machines 2024, 12(9), 659; https://doi.org/10.3390/machines12090659 - 20 Sep 2024

Viewed by 415

Abstract

This paper proposes an optimal path type classification scheme for the three-point Dubins problem. It allows us to directly extract the shortest path type from a Dubins set, evaluating only the relative initial and final configurations with the via point position using a [...] Read more.

This paper proposes an optimal path type classification scheme for the three-point Dubins problem. It allows us to directly extract the shortest path type from a Dubins set, evaluating only the relative initial and final configurations with the via point position using a suitable partition of the Cartesian plane. Two alternative approaches are proposed to address the problem: an analytical approach and a heuristic one. The latter is revealed to be much faster from a computational point of view. The proposed classification logic makes the path planning for the three-point Dubins problem much more effective and suitable for real-time applications. Numerical examples are provided to show the efficiency of the proposed strategy. Full article

(This article belongs to the Special Issue Autonomous Navigation of Mobile Robots and UAV)

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13 pages, 1035 KiB

Open AccessArticle

A New Method for Displacement Modelling of Serial Robots Using Finite Screw

by Feiyang Xue, Zhengjun Fang, Jiahao Song, Qi Liu and Shuofei Yang

Machines 2024, 12(9), 658; https://doi.org/10.3390/machines12090658 - 20 Sep 2024

Viewed by 528

Abstract

Kinematics is a hot topic in robotic research, serving as a foundational step in the synthesis and analysis of robots. Forward kinematics and inverse kinematics are the prerequisite and foundation for motion control, trajectory planning, dynamic simulation, and precision guarantee of robotic manipulators. [...] Read more.

Kinematics is a hot topic in robotic research, serving as a foundational step in the synthesis and analysis of robots. Forward kinematics and inverse kinematics are the prerequisite and foundation for motion control, trajectory planning, dynamic simulation, and precision guarantee of robotic manipulators. Both of them depend on the displacement models. Compared with the previous work, finite screw is proven to be the simplest and nonredundant mathematical tool for displacement description. Thus, it is used for displacement modelling of serial robots in this paper. Firstly, a finite-screw-based method for formulating displacement model is proposed, which is applicable for any serial robot. Secondly, the procedures for forward and inverse kinematics by solving the formulated displacement equation are discussed. Then, two typical serial robots with three translations and two rotations are taken as examples to illustrate the proposed method. Finally, through Matlab simulation, the obtained analytical expressions of kinematics are verified. The main contribution of the proposed method is that finite-screw-based displacement model is highly related with instantaneous-screw-based kinematic and dynamic models, providing an integrated modelling and analysis methodology for robotic mechanisms. Full article

(This article belongs to the Special Issue The Kinematics and Dynamics of Mechanisms and Robots)

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18 pages, 3540 KiB

Open AccessArticle

Geometric Parameter Optimization for Axial Modification in Helical Gear Form Grinding

by Bo Zhang, Yu Zhang, Longjie Zhang, Qingyu Li and Xiaoyi Wang

Machines 2024, 12(9), 657; https://doi.org/10.3390/machines12090657 - 20 Sep 2024

Viewed by 489

Abstract

During the axial modification in helical gear form grinding, the contact line between the grinding wheel and the gear constantly changes, and the additional radial motion can cause a “tooth surface twist” phenomenon. An optimization method for tooth surface twist error was proposed [...] Read more.

During the axial modification in helical gear form grinding, the contact line between the grinding wheel and the gear constantly changes, and the additional radial motion can cause a “tooth surface twist” phenomenon. An optimization method for tooth surface twist error was proposed to address this. Based on the gear meshing principles, a mathematical model for axial modification in form grinding was established to solve for the instantaneous contact lines at various positions on the actual modified tooth surface. By analyzing the influence of the grinding wheel installation angle on the axial modification contact line, an optimization model was constructed to reduce the twist of the transverse profile, reduce the twist of the flank profile, reduce the helix deviation, and improve the form grinding efficiency. The practical implications of this research are significant, as the Particle Swarm Optimization (PSO) algorithm was employed to optimize the form grinding parameters, leading to a method that effectively reduced tooth surface twist error and improved the form grinding accuracy of the modified tooth surface. Full article

(This article belongs to the Section Advanced Manufacturing)

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15 pages, 13940 KiB

Open AccessArticle

Research on Coal-Releasing Characteristics of Hydraulic Support for a Large Inclined-Angle Comprehensive Workface

by Lianmin Cao, Mingyan Geng, Rui Shen, Dekang Zhang and Xiaowei Zhang

Machines 2024, 12(9), 656; https://doi.org/10.3390/machines12090656 - 20 Sep 2024

Viewed by 490

Abstract

This research aimed to examine shortcomings such as low efficiency and unstable coal release of 2313 large inclined-angle comprehensively released working faces in 230 mining areas of a mine in Shandong. Through the study of the actual working conditions of the large inclined-angle [...] Read more.

This research aimed to examine shortcomings such as low efficiency and unstable coal release of 2313 large inclined-angle comprehensively released working faces in 230 mining areas of a mine in Shandong. Through the study of the actual working conditions of the large inclined-angle comprehensive release working face, it is concluded that the mining efficiency of the large inclined-angle coal seam is mainly related to the sequence of coal release, the step distance of the coal release, the distance between the end faces, the mining height, the working resistance of the hydraulic bracket and other factors. Taking ZF5600/16.5/26 hydraulic support as an example, simulation software was used to study the influencing factors of coal release efficiency, and the most efficient coal release method was found through the control variable method, so as to improve the mining recovery efficiency of the overall working face of the large inclined-angle coal seam, and after optimizing the working conditions of the hydraulic support, the top coal recovery efficiency was increased by 14.3% compared with the previous one after the actual statistics of the field situation. Full article

(This article belongs to the Section Machine Design and Theory)

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14 pages, 8270 KiB

Open AccessArticle

Design and Analysis of a Highly Reliable Permanent Magnet Synchronous Machine for Flywheel Energy Storage

by Xinjian Jiang, Lei Zhang, Fuwang Li and Zhenghui Zhao

Machines 2024, 12(9), 655; https://doi.org/10.3390/machines12090655 - 19 Sep 2024

Viewed by 628

Abstract

This article aims to propose a highly reliable permanent magnet synchronous machine (PMSM) for flywheel energy-storage systems. Flywheel energy-storage systems are large-capacity energy storage technologies suitable for the short-term storage of electrical energy. PMSMs have been used in the flywheel energy-storage systems due [...] Read more.

This article aims to propose a highly reliable permanent magnet synchronous machine (PMSM) for flywheel energy-storage systems. Flywheel energy-storage systems are large-capacity energy storage technologies suitable for the short-term storage of electrical energy. PMSMs have been used in the flywheel energy-storage systems due to their advantages. One of the key requirements for PMSMs in flywheel energy-storage systems is high reliability. A double redundant winding structure is adopted to ensure fault-tolerant operation of the PMSM. The stator is designed with auxiliary teeth to reduce the short-circuit current. Moreover, the number of slots and poles is determined to ensure the winding factor, heat dissipation, and reduce losses. Moreover, the dual three-phase stator winding structure and auxiliary teeth are adopted on the PMSM to improve reliability. Afterward, the electromagnetic performance is analyzed, and the mechanical stress is investigated to ensure mechanical strength. Finally, a prototype is built and tested to verify the theoretical analysis and performance of the PMSM. Full article

(This article belongs to the Section Electrical Machines and Drives)

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14 pages, 3489 KiB

Open AccessArticle

The Tightening and Untightening Modeling and Simulation of Bolted Joints

by Rashique Iftekhar Rousseau and Abdel-Hakim Bouzid

Machines 2024, 12(9), 654; https://doi.org/10.3390/machines12090654 - 19 Sep 2024

Viewed by 981

Abstract

Although bolted joints may appear simple and are easy to manipulate, they are challenging to model and analyze due to their complex structural patterns and statically indeterminate nature. Ensuring the structural integrity of these joints requires maintaining proper bolt preload and clamping force, [...] Read more.

Although bolted joints may appear simple and are easy to manipulate, they are challenging to model and analyze due to their complex structural patterns and statically indeterminate nature. Ensuring the structural integrity of these joints requires maintaining proper bolt preload and clamping force, which is crucial for preventing failures such as overload, excessive bearing stress, fatigue, and stripping caused by seizing or galling. Achieving the necessary clamping force involves carefully controlling the input tightening torque, which is divided into the pitch torque and the friction torques at the bolt or nut bearing surfaces and in the engaged threads. The resulting clamping force is critical for generating the required force within the bolt. However, the achieved bolt force depends on several factors, such as friction at the joint’s contact surfaces, grip length, and the relative rotation between the bolt and nut during tightening. Friction at the contact surfaces, particularly beneath the bolt head or nut and between the threads, consumes a significant portion of the applied tightening torque—approximately 90%. This paper explores the three existing bolt internal pitch, bearing, and thread friction torques that are generated by the external applied torque in a bolted joint, as well as their contributions and variations throughout a loading cycle composed of three phases: tightening, settling, and untightening. An analytical model is developed to determine these torque components, and its results are compared with those obtained from finite element (FE) modeling and experimental testing from previous studies. Finally, this study examines the torque–tension relationship during bolt tightening, offering insights into the required accuracy of bolt and clamped member stiffness. The bolt samples used in this study include M12 × 1.75 and M36 × 4 hex bolts. Full article

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

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30 pages, 23730 KiB

Open AccessArticle

Design and Performance of a Novel Tapered Wing Tiltrotor UAV for Hover and Cruise Missions

by Edgar Ulises Rojo-Rodriguez, Erik Gilberto Rojo-Rodriguez, Sergio A. Araujo-Estrada and Octavio Garcia-Salazar

Machines 2024, 12(9), 653; https://doi.org/10.3390/machines12090653 - 18 Sep 2024

Viewed by 1424

Abstract

This research focuses on a novel convertible unmanned aerial vehicle (CUAV) featuring four rotors with tilting capabilities combined with a tapered form. This paper studies the transition motion between multirotor and fixed-wing modes based on the mechanical and aerodynamics design as well as [...] Read more.

This research focuses on a novel convertible unmanned aerial vehicle (CUAV) featuring four rotors with tilting capabilities combined with a tapered form. This paper studies the transition motion between multirotor and fixed-wing modes based on the mechanical and aerodynamics design as well as the control strategy. The proposed CUAV involves information about design, manufacturing, operation, modeling, control strategy, and real-time experiments. The CUAV design considers a fixed-wing with tiltrotors and provides the maneuverability to perform take-off, hover flight, cruise flight, and landing, having the characteristics of a helicopter in hover flight and an aircraft in horizontal flight. The manufacturing is based on additive manufacturing, which facilitates the creation of a lattice structure within the wing. The modeling is obtained using the Newton–Euler equations, and the control strategy is a PID controller based on a geometric approach on SE(3). Finally, the real-time experiments validate the proposed design for the complete regime of flight, and the research meticulously evaluates the feasibility of the prototype and its potential to significantly enhance the mission versatility. Full article

(This article belongs to the Special Issue Advances and Applications in Unmanned Aerial Vehicles)

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21 pages, 22248 KiB

Open AccessArticle

Prediction Method for Mechanical Characteristic Parameters of Weak Components of 110 kV Transmission Tower under Ice-Covered Condition Based on Finite Element Simulation and Machine Learning

by Lin Yang, Lulu Mei, Yifei Chen, Yanpeng Hao, Licheng Li, Jianrong Wu and Xianyin Mao

Machines 2024, 12(9), 652; https://doi.org/10.3390/machines12090652 - 18 Sep 2024

Viewed by 455

Abstract

Icing on transmission lines may cause damage to tower components and even lead to structural failure. Aiming at the lack of research on predicting mechanical characteristic parameters of weak components of transmission towers, and the cumbersome steps of building a finite element model [...] Read more.

Icing on transmission lines may cause damage to tower components and even lead to structural failure. Aiming at the lack of research on predicting mechanical characteristic parameters of weak components of transmission towers, and the cumbersome steps of building a finite element model (FEM), the study of prediction for mechanical characteristic parameters of weak components of towers based on a finite element simulation and machine learning is proposed. Firstly, a 110 kV transmission tower in a heavily iced area is taken as an example to establish its FEM. The locations of the weak components are analyzed, and the accuracy of FEM is verified. Secondly, meteorological and terrain parameters are considered as input parameters of the prediction model. The axial stresses and nodal displacements of four weak components are selected as output parameters. The FEM of the 110 kV transmission tower is used to obtain input and output datasets. Thirdly, five machine learning algorithms are considered to establish the prediction models for mechanical characteristic parameters of weak components, and the optimal prediction model is obtained. Finally, the accuracy of the prediction method is verified through an actual tower collapse case. The results show that ACO-BPNN is the optimal model that can accurately and quickly predict the mechanical characteristic parameters of the weak components of the transmission tower. This study can provide an early warning for the failure prediction of transmission towers in heavily iced areas, thus providing an important reference for their safe operation and maintenance. Full article

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

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23 pages, 3680 KiB

Open AccessArticle

Geometric Modeling and Error Propagation Analysis of an Over-Constrained Spindle Head with Kinematic Interactions

by Yifeng Shen, Tengfei Tang and Hanliang Fang

Machines 2024, 12(9), 651; https://doi.org/10.3390/machines12090651 - 18 Sep 2024

Viewed by 479

Abstract

This study presents a comprehensive geometric modeling and error propagation analysis for a 3-degrees-of-freedom spindle head, focusing on an over-constrained parallel mechanism. Four geometric error models are established for the over-constrained spindle head, each considering different combinations of constraint wrenches. A set of [...] Read more.

This study presents a comprehensive geometric modeling and error propagation analysis for a 3-degrees-of-freedom spindle head, focusing on an over-constrained parallel mechanism. Four geometric error models are established for the over-constrained spindle head, each considering different combinations of constraint wrenches. A set of sensitivity indices is formulated to evaluate the effectiveness of these models. Comparative sensitivity analysis suggests that a model incorporating all constraint wrenches is suitable for error propagation analysis. Two error propagation indices are introduced to quantify the impact of the geometric source errors on the position and orientation of an individual limb structure. The coupled error propagation indices account for the kinematic interactions among limb structures, allowing for a detailed analysis of the spindle head’s terminal accuracy. The relative deviations of error propagation indices are utilized to assess the quantitative impact of kinematic interactions on the geometric errors of an individual limb structure. Furthermore, this study analyzes the cumulative effects of kinematic errors from three limb structures to reflect the influence of kinematic interactions on the terminal accuracy of the spindle head. The findings indicate that geometric errors of the limbs in such an over-constrained spindle head are mutually compensatory, reducing linear and angular errors and enhancing the spindle head’s terminal accuracy. Full article

(This article belongs to the Section Machine Design and Theory)

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14 pages, 4190 KiB

Open AccessArticle

Research on Trajectory Planning and Tracking Algorithm of Crawler Paver

by Jian Zhan, Wei Li, Jiongfan Wang, Shusheng Xiong, Xiaofeng Wu and Wei Shi

Machines 2024, 12(9), 650; https://doi.org/10.3390/machines12090650 - 17 Sep 2024

Viewed by 544

Abstract

The implementation of unmanned intelligent construction on the concrete surfaces of an airport effectively improves construction accuracy and reduces personnel investment. On the basis of three known common tracked vehicle dynamics models, reference trajectory planning and trajectory tracking controller algorithms need to be [...] Read more.

The implementation of unmanned intelligent construction on the concrete surfaces of an airport effectively improves construction accuracy and reduces personnel investment. On the basis of three known common tracked vehicle dynamics models, reference trajectory planning and trajectory tracking controller algorithms need to be designed. In this paper, based on the driving characteristics of the tracked vehicle and the requirements of the stepping trajectory, a quartic polynomial trajectory planning algorithm was selected with the stability of the curve as a whole and the end point as the optimization goal, combining the tracked vehicle dynamics model, collision constraints, start–stop constraints and other boundary conditions. The objective function of trajectory planning was designed to effectively plan the reference trajectory of the tracked vehicle’s step-by-step travel. In order to realize accurate trajectory tracking control, a nonlinear model predictive controller with transverse-longitudinal integrated control was designed. To improve the real-time performance of the controller, a linear model predictive controller with horizontal and longitudinal decoupling was designed. MATLAB 2023A and CoppeliaSim V4.5.1 were used to co-simulate the two controller models. The experimental results show that the advantages and disadvantages of the tracked vehicle dynamics model and controller design are verified. Full article

(This article belongs to the Section Vehicle Engineering)

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15 pages, 6360 KiB

Open AccessArticle

Experimental Determination of Influences of Static Eccentricities on the Structural Dynamic Behavior of a Permanent Magnet Synchronous Machine

by Julius Müller, Marius Franck, Kevin Jansen, Gregor Höpfner, Jörg Berroth, Georg Jacobs and Kay Hameyer

Machines 2024, 12(9), 649; https://doi.org/10.3390/machines12090649 - 16 Sep 2024

Viewed by 605

Abstract

In electrified vehicles, the masking noise behavior of internal combustion engines is absent, making the tonal excitation of the electric machine particularly noticeable in vehicle acoustics, which is perceived as disturbing by consumers. Due to manufacturing tolerances, the tonal NVH characteristics of the [...] Read more.

In electrified vehicles, the masking noise behavior of internal combustion engines is absent, making the tonal excitation of the electric machine particularly noticeable in vehicle acoustics, which is perceived as disturbing by consumers. Due to manufacturing tolerances, the tonal NVH characteristics of the electric machine are significantly influenced at wide frequency ranges. This paper presents a systematic exploration of the influence of static eccentricity as one manufacturing tolerance on the NVH behavior of Permanent Magnet Synchronous Machines (PMSMs). The study utilizes a novel test bench setup enabling isolated variations in static eccentricity of up to 0.2 mm in one PMSM. Comparative analysis of acceleration signals reveals significant variations in the dominance of excitation orders with different eccentricity states, impacting critical operating points and dominant frequency rages of the electric machine. Despite experimentation, no linear correlation is observed between increased eccentricity and changes in acceleration behavior. Manufacturing eccentricity and deviations in rotor magnetization are discussed as potential contributors to the observed effects. The findings emphasize static eccentricity as a critical parameter in NVH optimization, particularly in electrified powertrains. However, the results indicate that further investigations are needed to explore the influence of eccentricities and magnetization deviations on NVH behavior comprehensively. Full article

(This article belongs to the Special Issue Noise and Vibrations of Electrical Machines)

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22 pages, 15594 KiB

Open AccessArticle

Analysis of Scraper Conveyor Chain Dynamics under Falling Coal Impact Conditions

by Shoubo Jiang, Yuqi Zhang, Qingliang Zeng, Shaojie Chen, Wei Qu and Hongwei Zhang

Machines 2024, 12(9), 648; https://doi.org/10.3390/machines12090648 - 15 Sep 2024

Viewed by 640

Abstract

The scraper conveyor, essential for mechanized mining, operates in harsh underground environments and is subjected to severe impact loads from coal and rock falls. Such conditions can cause chain jamming, breakage, and other malfunctions, necessitating a detailed study of the system’s dynamic behavior [...] Read more.

The scraper conveyor, essential for mechanized mining, operates in harsh underground environments and is subjected to severe impact loads from coal and rock falls. Such conditions can cause chain jamming, breakage, and other malfunctions, necessitating a detailed study of the system’s dynamic behavior under impact conditions. This study investigates the dynamic characteristics of a scraper conveyor’s chain drive system using a coupled ADAMS-EDEM simulation model. The model analyzes the effects of loaded coal piles on the conveyor’s dynamics during normal and impact conditions. Simulations show that loaded coal piles excite the scraper’s acceleration and sprocket rotation, with the greatest impact in the scraper’s running direction. Longitudinal impact and contact forces on the chain ring are more significant than in other directions under both no-load and loaded conditions. A strong linear relationship exists between the falling coal mass and longitudinal impact force. The coal pile causes prominent longitudinal vibration excitation while inhibiting the overall vibration of the chain drive system to some extent. The findings provide insights for identifying failure-prone areas under impact conditions and offer theoretical guidance for optimizing scraper conveyor design. This enhances mining efficiency and safety in coal operations. Full article

(This article belongs to the Section Automation and Control Systems)

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15 pages, 2095 KiB

Open AccessArticle

Efficiency of Bevel and Hypoid Gears—Test Rig Development and Experimental Investigations

by Lorenz Constien, Martin Weber, Josef Pellkofer and Karsten Stahl

Machines 2024, 12(9), 647; https://doi.org/10.3390/machines12090647 - 15 Sep 2024

Viewed by 945

Abstract

The efficiency of bevel and hypoid gears is, alongside load capacity, one of their most important design criteria. To consider the efficiency of bevel and hypoid gears during the development and design process, validated calculation methods based on experimental investigations are necessary. However, [...] Read more.

The efficiency of bevel and hypoid gears is, alongside load capacity, one of their most important design criteria. To consider the efficiency of bevel and hypoid gears during the development and design process, validated calculation methods based on experimental investigations are necessary. However, the isolated experimental investigation of the load-dependent power losses of bevel and hypoid gears has not been adequately investigated, as most of the experimental investigations consider the complete gearbox. This paper presents a test rig that allows for the experimental investigation of the efficiency of bevel and hypoid gears with a measurement uncertainty of the efficiency of

∆ η \leq \pm 0.08 %

according to the Guide to the Expression of Uncertainty in Measurement (GUM). Using the developed test rig, experimental investigations on the efficiency behavior of bevel and hypoid gears regarding the influence of the axial offset, driving direction, and microgeometry are carried out for different operating points varying in circumferential speed and load. This paper discusses the methodology and the first experimental results of a study on the efficiency of bevel and hypoid gears in detail. Full article

(This article belongs to the Special Issue Advancements in Mechanical Power Transmission and Its Elements)

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18 pages, 15291 KiB

Open AccessArticle

Optimization of Tool Wear and Cutting Parameters in SCCO₂-MQL Ultrasonic Vibration Milling of SiCp/Al Composites

by Huiping Zhang, Bowen Wang, Liqiang Qu and Xinran Wang

Machines 2024, 12(9), 646; https://doi.org/10.3390/machines12090646 - 14 Sep 2024

Viewed by 798

Abstract

Silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites are significant lightweight metal matrix composites extensively utilized in precision instruments and aerospace sectors. Nevertheless, the inclusion of rigid SiC particles exacerbates tool wear in mechanical machining, resulting in a decline in the quality of surface [...] Read more.

Silicon carbide particle-reinforced aluminum matrix (SiCp/Al) composites are significant lightweight metal matrix composites extensively utilized in precision instruments and aerospace sectors. Nevertheless, the inclusion of rigid SiC particles exacerbates tool wear in mechanical machining, resulting in a decline in the quality of surface finishes. This work undertakes a comprehensive investigation into the problem of tool wear in SiCp/Al composite materials throughout the machining process. Initially, a comprehensive investigation was conducted to analyze the effects of cutting velocity v_c, feed per tooth f_z, milling depth a_p, and milling width a_e on tool wear during high-speed milling under SCCO₂-MQL (Supercritical Carbon Dioxide Minimum Quantity Lubrication) ultrasonic vibration conditions. The results show that under the condition of SCCO₂-MQL ultrasonic vibration, proper control of milling parameters can significantly reduce tool wear, extend tool service life, improve machining quality, and effectively reduce blade breakage and spalling damage to the tool, reduce abrasive wear and adhesive wear, and thus significantly improve the durability of the tool. Furthermore, a prediction model for tool wear was developed by employing the orthogonal test method and multiple linear regression. The model’s relevance and accuracy were confirmed using F-tests and t-tests. The results show that the model can effectively predict tool wear, among which cutting velocity v_c and feed rate f_z are the key parameters affecting the prediction accuracy. Finally, a genetic algorithm was used to optimize the milling parameters, and the optimal parameter combination (v_c = 60.00 m/min, f_z = 0.08 mm/z, a_p = 0.20 mm) was determined, and the optimized milling parameters were tested. Empirical findings suggest that the careful selection of milling parameters can significantly mitigate tool wear, extend the lifespan of the tool, and enhance the quality of the surface. This work serves as a significant point of reference for the processing of SiCp/Al composite materials. Full article

(This article belongs to the Special Issue Machine Tools for Precision Machining: Design, Control and Prospects)

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42 pages, 11801 KiB

Open AccessArticle

Multidimensional Taxonomies for Research, Development, and Implementation of Electric Aircraft Ecosystem

by Igor Kabashkin

Machines 2024, 12(9), 645; https://doi.org/10.3390/machines12090645 - 14 Sep 2024

Cited by 1 | Viewed by 926

Abstract

The electrification of aviation represents a significant technological frontier, promising substantial advancements in sustainable transportation. This paper presents a comprehensive set of taxonomies that systematically categorize and analyze the multifaceted aspects of electric aviation, with a particular focus on machine-related components and systems. [...] Read more.

The electrification of aviation represents a significant technological frontier, promising substantial advancements in sustainable transportation. This paper presents a comprehensive set of taxonomies that systematically categorize and analyze the multifaceted aspects of electric aviation, with a particular focus on machine-related components and systems. It provides detailed classifications of electric aircraft propulsion systems, power management architectures, and energy storage technologies, offering insight into their design, functionality, and integration challenges. The paper explores the ecosystem of electric aviation, including key stakeholders, use cases, and enabling technologies, which are vital for coordinating machine development strategies and fostering sustainable growth. The creation of business models that cater to the dynamic nature of the industry, emphasizing the role of innovative machine designs in shaping market adoption are discussed in the paper. The study highlights the importance of electric aviation for regional development, outlining predictive models for regional market development that consider machine capabilities and infrastructure requirements. Full article

(This article belongs to the Section Machine Design and Theory)

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15 pages, 3408 KiB

Open AccessArticle

Calculation of Wear of Railway Wheels with Multibody Codes: Benchmarking of the Modelling Choices

by Matteo Magelli and Nicolò Zampieri

Machines 2024, 12(9), 644; https://doi.org/10.3390/machines12090644 - 14 Sep 2024

Viewed by 723

Abstract

The numerical simulation of wear of railway wheel profiles can be a game changer in the railway field, as it can drive the planning of wheel re-turning operations, thrust the identification of optimized profiles and evaluate the safety of railway vehicles at the [...] Read more.

The numerical simulation of wear of railway wheel profiles can be a game changer in the railway field, as it can drive the planning of wheel re-turning operations, thrust the identification of optimized profiles and evaluate the safety of railway vehicles at the early stages of design. Today, commercial multibody codes are provided with dedicated routines that can evaluate the worn profile shape due to the dynamic behaviour of the vehicle. As the outputs of such modules can depend on different user-selectable parameters and modelling choices, it is vital to assess the capabilities of these codes and get a further understanding of the implemented algorithms. This paper aims to benchmark the effects of different modelling parameters and choices, mainly related to the selected wear law and wheel–rail contact method, on the final wear outputs, with special reference to the wear module provided by the SIMPACK commercial multibody code. A relevant novelty of the paper deals with the benchmarking of the wear algorithm available in the commercial code with in-house wear routines, comparing different strategies and choices for the calculation of wear. This allows us to better understand the most critical differences and modelling issues, as well as to highlight possible improvements in wear algorithms that can lead to enhanced numerical stability. More in detail, this work suggests a change in the wear algorithm that proves to be beneficial to removing local wear peaks produced by numerical sources, which could cause instabilities in the computation. Full article

(This article belongs to the Section Vehicle Engineering)

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24 pages, 9418 KiB

Open AccessArticle

A New Zero Waste Design for a Manufacturing Approach for Direct-Drive Wind Turbine Electrical Generator Structural Components

by Daniel Gonzalez-Delgado, Pablo Jaen-Sola and Erkan Oterkus

Machines 2024, 12(9), 643; https://doi.org/10.3390/machines12090643 - 14 Sep 2024

Cited by 1 | Viewed by 855

Abstract

An integrated structural optimization strategy was produced in this study for direct-drive electrical generator structures of offshore wind turbines, implementing a design for an additive manufacturing approach, and using generative design techniques. Direct-drive configurations are widely implemented on offshore wind energy systems due [...] Read more.

An integrated structural optimization strategy was produced in this study for direct-drive electrical generator structures of offshore wind turbines, implementing a design for an additive manufacturing approach, and using generative design techniques. Direct-drive configurations are widely implemented on offshore wind energy systems due to their high efficiency, reliability, and structural simplicity. However, the greatest challenge associated with these types of machines is the structural optimization of the electrical generator due to the demanding operating conditions. An integrated structural optimization strategy was developed to assess a 100-kW permanent magnet direct-drive generator structure. Generated topologies were evaluated by performing finite element analyses and a metal additive manufacturing process simulation. This novel approach assembles a vast amount of structural information to produce a fit-for-purpose, adaptative, optimization strategy, combining data from static structural analyses, modal analyses, and manufacturing analyses to automatically generate an efficient model through a generative iterative process. The results obtained in this study demonstrate the importance of developing an integrated structural optimization strategy at an early phase of a large-scale project. By considering the typical working condition loads and the machine’s dynamic behavior through the structure’s natural frequencies during the optimization process coupled with a design for an additive manufacturing approach, the operational range of the wind turbine was maximized, the overall costs were reduced, and production times were significantly diminished. Integrating the constraints associated with the additive manufacturing process into the design stage produced high-efficiency results with over 23% in weight reduction when compared with conventional structural optimization techniques. Full article

(This article belongs to the Section Turbomachinery)

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25 pages, 14386 KiB

Open AccessArticle

Deep Learning-Based Real-Time 6D Pose Estimation and Multi-Mode Tracking Algorithms for Citrus-Harvesting Robots

by Hyun-Jung Hwang, Jae-Hoon Cho and Yong-Tae Kim

Machines 2024, 12(9), 642; https://doi.org/10.3390/machines12090642 - 13 Sep 2024

Viewed by 944

Abstract

In the agricultural sector, utilizing robots for tasks such as fruit harvesting poses significant challenges, particularly in achieving accurate 6D pose estimation of the target objects, which is essential for precise and efficient harvesting. Particularly, fruit harvesting relies heavily on manual labor, leading [...] Read more.

In the agricultural sector, utilizing robots for tasks such as fruit harvesting poses significant challenges, particularly in achieving accurate 6D pose estimation of the target objects, which is essential for precise and efficient harvesting. Particularly, fruit harvesting relies heavily on manual labor, leading to issues with an unstable labor supply and rising costs. To solve these problems, agricultural harvesting robots are gaining attention. However, effective harvesting necessitates accurate 6D pose estimation of the target object. This study proposes a method to enhance the performance of fruit-harvesting robots, including the development of a dataset named HWANGMOD, which was created using both virtual and real environments with tools such as Blender and BlenderProc. Additionally, we present methods for training an EfficientPose-based model for 6D pose estimation and ripeness classification, and an algorithm for determining the optimal harvest sequence among multiple fruits. Finally, we propose a multi-object tracking method using coordinates estimated by deep learning models to improve the robot’s performance in dynamic environments. The proposed methods were evaluated using metrics such as

A D D

and

A D D S

, showing that the deep learning model for agricultural harvesting robots excelled in accuracy, robustness, and real-time processing. These advancements contribute to the potential for commercialization of agricultural harvesting robots and the broader field of agricultural automation technology. Full article

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

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15 pages, 8060 KiB

Open AccessArticle

Influence of Check Gate Construction on Operation of Check Gate in Ship Lock

by Jozef Kulka, Martin Mantič, Melichar Kopas, Michal Fabian, Robert Grega, Peter Kaššay and Marián Siman

Machines 2024, 12(9), 641; https://doi.org/10.3390/machines12090641 - 13 Sep 2024

Viewed by 518

Abstract

The subject of investigation presented in this article is a filling and draining system of the ship lock installed in the Gabčíkovo Waterworks. This article describes the operation and construction of the special regulation segments, i.e., the check gates that are situated in [...] Read more.

The subject of investigation presented in this article is a filling and draining system of the ship lock installed in the Gabčíkovo Waterworks. This article describes the operation and construction of the special regulation segments, i.e., the check gates that are situated in the ship locks. After the failure and replacement of the original check gate with the new, improved one, the strain gauge sensors were applied to the new check gate in order to determine stress distribution on the segment surface as well as the loading of the actuating arms. The application method and application places of the strain gauge sensors are described in detail. The performed measurements detected the occurrence of additional motional resistances during the opening and closing of the check gate. These resistances caused a partial non-functionality of the original check gate actuating mechanism. Full article

(This article belongs to the Topic Uncertainty Quantification in Design, Manufacturing and Maintenance of Complex Systems)

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16 pages, 5669 KiB

Open AccessArticle

Investigation on the Dynamic Characteristics of a New High-Pressure Water Hydraulic Flow Control Valve

by Wenchao Liu, Jie Tian, Hongyao Wang, Junshi Li, Rulin Zhou and Yu Cao

Machines 2024, 12(9), 640; https://doi.org/10.3390/machines12090640 - 12 Sep 2024

Viewed by 561

Abstract

Water has the disadvantages of low viscosity, poor lubrication, and easy leakage, which leads to many problems in water hydraulic flow control valves, such as low working pressure and large flow fluctuations. To address these issues, this paper proposes a novel digital flow [...] Read more.

Water has the disadvantages of low viscosity, poor lubrication, and easy leakage, which leads to many problems in water hydraulic flow control valves, such as low working pressure and large flow fluctuations. To address these issues, this paper proposes a novel digital flow control valve. The valve uses a linear stepper motor as the driving device. Compared to proportional electromagnets, the thrust and stroke of the linear stepper motor are larger, making the valve more suitable for high-pressure working conditions. Simultaneously, the valve innovatively incorporates a set of pilot valve spool strings at the front end of the pilot valve damping hole. Through controlling the two pilot valves to regulate the pressure difference before and after the damping hole, the flow passing through the pilot valve is maintained stable, thereby making the pressure of the upper chamber of the master valve spool more stable. In comparison to a single pilot valve structure, this design ensures a more stable main valve core position and reduces flow fluctuation. A mathematical and simulation model of the valve has been established, confirming the performance advantages of the new structure. The impact of structural parameters (such as valve core diameter, spring stiffness, and diameter of damping hole) on the stability of flow regulation has been investigated. A genetic algorithm has been employed to optimize the key parameters that influence valve flow stability, resulting in the identification of optimal parameters. The simulation results indicate that the optimized parameters lead to a reduction of approximately 45% in the maximum overshoot oscillation amplitude of the valve flow regulation. A prototype of the new flow control valve was developed, and a test system was established for conducting tests. The test results also confirmed the performance advantages of the valve and the accuracy of the optimal design. Full article

(This article belongs to the Section Turbomachinery)

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19 pages, 6916 KiB

Open AccessArticle

Design and Testing of a Fully Automatic Aquatic Plant Combing Machine for Crab Farming

by Shijie Yuan, Jintao Xu, Hao Yuan, Jinsheng Ku and Zexin Liu

Machines 2024, 12(9), 639; https://doi.org/10.3390/machines12090639 - 12 Sep 2024

Viewed by 479

Abstract

To meet the requirements of the crab growth environment regarding aquatic plant density and improve the efficiency of aquatic plant clearing, this paper shows the development process of a fully automatic aquatic plant combing machine for crab farming. It proposed the use of [...] Read more.

To meet the requirements of the crab growth environment regarding aquatic plant density and improve the efficiency of aquatic plant clearing, this paper shows the development process of a fully automatic aquatic plant combing machine for crab farming. It proposed the use of torsion spring hooks to replace traditional cutting blades to break tangled aquatic plants, reducing the length of aquatic plants in dense areas and thus controlling the density of aquatic plants in crab ponds. Through theoretical analysis and calculation of the torsion spring hooks, it was ensured that they could meet the design requirements, and transient dynamic simulation tests were conducted based on ANSYS. Finally, experimental verification was carried out. The performance test results of the torsion spring hooks showed that the torsion force generated within a certain torsion angle range could break the aquatic plant, and obstacles could be avoided through self-deformation. The water performance test results showed that the average clearing efficiency of the whole machine for aquatic plants was 4.92 mu/h, the missed clearing rate of aquatic plants was 0.44%, and the crab injury rate was 0.028%. The design of this machine can provide a reference for the development of aquatic plant harvesters for crab farming. Full article

(This article belongs to the Section Machine Design and Theory)

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15 pages, 456 KiB

Open AccessArticle

Analytical Modeling and Experimental Validation of the Coefficient of Friction in AlSi10Mg-SiC Composites

by Saba Iftikhar, Mihail Kolev and Dimitar Kolev

Machines 2024, 12(9), 638; https://doi.org/10.3390/machines12090638 - 12 Sep 2024

Viewed by 470

Abstract

Recognizing the lightweight nature and superior tribological properties of Al-based metal matrix composites, this study introduces a novel analytical model based on polynomial approximations, offering new insights into the mechanisms of dry friction in AlSi10Mg-SiC composite materials. Key findings highlight a significant reduction [...] Read more.

Recognizing the lightweight nature and superior tribological properties of Al-based metal matrix composites, this study introduces a novel analytical model based on polynomial approximations, offering new insights into the mechanisms of dry friction in AlSi10Mg-SiC composite materials. Key findings highlight a significant reduction in the coefficient of friction (COF) and oscillation amplitudes in SiC-reinforced composites, indicating superior tribological performance compared to their unreinforced counterparts. This behavior is attributed to the effective distribution of SiC particles within the aluminum matrix, which mitigates the stick–slip motion commonly observed under dry sliding conditions. Importantly, the model using polynomial approximations is noted for its simplicity and ease of implementation in practice. The study’s conclusions not only underscore the benefits of SiC reinforcement in enhancing wear resistance but also contribute to the broader field of materials science by providing a robust framework for the predictive modeling of COF in various composite systems. Full article

(This article belongs to the Special Issue Composites Machining in Manufacturing)

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22 pages, 8328 KiB

Open AccessArticle

Research on Fault Diagnosis Method with Adaptive Artificial Gorilla Troops Optimization Optimized Variational Mode Decomposition and Support Vector Machine Parameters

by Ting Fang, Long Ma and Hongkai Zhang

Machines 2024, 12(9), 637; https://doi.org/10.3390/machines12090637 - 12 Sep 2024

Viewed by 600

Abstract

To address the issue of intelligent optimization algorithms being prone to local optima, resulting in insufficient feature extraction and low fault-type recognition rates when optimizing Variational Mode Decomposition and Support Vector Machine parameters, this paper proposes a fault diagnosis method based on an [...] Read more.

To address the issue of intelligent optimization algorithms being prone to local optima, resulting in insufficient feature extraction and low fault-type recognition rates when optimizing Variational Mode Decomposition and Support Vector Machine parameters, this paper proposes a fault diagnosis method based on an improved Artificial Gorilla Troops Optimization algorithm. The Artificial Gorilla Troops Optimization algorithm was enhanced using Logistic chaotic mapping, a linear decreasing weight factor, the global exploration strategy of the Osprey Optimization Algorithm, and the Levy flight strategy, improving its ability to escape local optima, adaptability, and convergence accuracy. This algorithm was used to optimize the parameters of Variational Mode Decomposition and Support Vector Machine for fault diagnosis. Experiments on fault diagnosis with two datasets of different sample sizes showed that the proposed method achieved a diagnostic accuracy of no less than 98% for samples of varying sizes, with stable and reliable results. Full article

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

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Machines, Volume 12, Issue 9 (September 2024) – 79 articles

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