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Machines, Volume 13, Issue 2 (February 2025) – 59 articles

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32 pages, 1230 KiB  
Article
Addressing Due Date and Storage Restrictions in the S-Graph Scheduling Framework
by Krisztián Attila Bakon and Tibor Holczinger
Machines 2025, 13(2), 131; https://doi.org/10.3390/machines13020131 (registering DOI) - 9 Feb 2025
Abstract
This paper addresses the Flexible Job Shop Scheduling Problem (FJSP) with the objective of minimizing both earliness/tardiness (E/T) and intermediate storage time (IST). An extended S-graph framework that incorporates E/T and IST minimization while maintaining the structural advantages of the original S-graph approach [...] Read more.
This paper addresses the Flexible Job Shop Scheduling Problem (FJSP) with the objective of minimizing both earliness/tardiness (E/T) and intermediate storage time (IST). An extended S-graph framework that incorporates E/T and IST minimization while maintaining the structural advantages of the original S-graph approach is presented. The framework is further enhanced by integrating linear programming (LP) techniques to adjust machine assignments and operation timings dynamically. The following four methodological approaches are systematically analyzed: a standalone S-graph for E/T minimization, an S-graph for combined E/T and IST minimization, a hybrid S-graph with LP for E/T minimization, and a comprehensive hybrid approach addressing both E/T and IST. Computational experiments on benchmark problems demonstrate the efficacy of the proposed methods, with the standalone S-graph showing efficiency for smaller instances and the hybrid approaches offering improved solution quality for more complex scenarios. The research provides insights into the trade-offs between computational time and solution quality across different problem configurations and storage policies. This work contributes to the field of production scheduling by offering a versatile framework capable of addressing the multi-objective nature of modern manufacturing environments. Full article
(This article belongs to the Section Advanced Manufacturing)
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29 pages, 4682 KiB  
Article
LSAF-LSTM-Based Self-Adaptive Multi-Sensor Fusion for Robust UAV State Estimation in Challenging Environments
by Mahammad Irfan, Sagar Dalai, Petar Trslic, James Riordan and Gerard Dooly
Machines 2025, 13(2), 130; https://doi.org/10.3390/machines13020130 (registering DOI) - 9 Feb 2025
Viewed by 146
Abstract
Unmanned aerial vehicle (UAV) state estimation is fundamental across applications like robot navigation, autonomous driving, virtual reality (VR), and augmented reality (AR). This research highlights the critical role of robust state estimation in ensuring safe and efficient autonomous UAV navigation, particularly in challenging [...] Read more.
Unmanned aerial vehicle (UAV) state estimation is fundamental across applications like robot navigation, autonomous driving, virtual reality (VR), and augmented reality (AR). This research highlights the critical role of robust state estimation in ensuring safe and efficient autonomous UAV navigation, particularly in challenging environments. We propose a deep learning-based adaptive sensor fusion framework for UAV state estimation, integrating multi-sensor data from stereo cameras, an IMU, two 3D LiDAR’s, and GPS. The framework dynamically adjusts fusion weights in real time using a long short-term memory (LSTM) model, enhancing robustness under diverse conditions such as illumination changes, structureless environments, degraded GPS signals, or complete signal loss where traditional single-sensor SLAM methods often fail. Validated on an in-house integrated UAV platform and evaluated against high-precision RTK ground truth, the algorithm incorporates deep learning-predicted fusion weights into an optimization-based odometry pipeline. The system delivers robust, consistent, and accurate state estimation, outperforming state-of-the-art techniques. Experimental results demonstrate its adaptability and effectiveness across challenging scenarios, showcasing significant advancements in UAV autonomy and reliability through the synergistic integration of deep learning and sensor fusion. Full article
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21 pages, 10981 KiB  
Article
Lumped Parameter Model for Structural Analysis of Over-Constrained Multi-Legged Parallel Mechanism Supporting System Applied to Cryogenic Devices
by Luca Piacentini, Luca Dassa, Diego Perini, Andris Ratkus, Toms Torims and Stefano Uberti
Machines 2025, 13(2), 129; https://doi.org/10.3390/machines13020129 (registering DOI) - 8 Feb 2025
Viewed by 110
Abstract
While the design of a cryostat is being developed, one of the most relevant sub-systems is the internal supporting system that sustains the cooled component. According to the literature, the arrangement and number of supports chosen often result in a multi-leg over-constrained architecture. [...] Read more.
While the design of a cryostat is being developed, one of the most relevant sub-systems is the internal supporting system that sustains the cooled component. According to the literature, the arrangement and number of supports chosen often result in a multi-leg over-constrained architecture. These are usually studied by means of finite element analysis tools alone, which makes studies like the optimization of supporting systems computationally expensive. This paper proposes a more structured and general analytical model compared to the existing models for this application. The proposed lumped parameter model allows designers to study the influence of external loads, pre-load, and cool-down on stress levels and deformation status of the supports of the cryogenic device as well as the consequent misalignment of the cooled component. The general lumped parameter model for n tie-rods of different shapes, dimensions, and materials is proposed. Two particularized models of eight and eleven supports are validated by comparing the results with those from standard finite element analysis software. Results show that the proposed model has a strong agreement with finite element simulations, and the median of relative errors is about 1.4%. This accuracy is obtained for models of randomly arranged supports, which proves the effectiveness of the model in predicting results even for non-symmetrical support configurations. Comparable and accurate results are obtained, which are about 130 times faster than in finite element analysis, thus proving the effective reduction in computational cost. Additionally, the proposed code lets designers change input parameters in a quicker and reliable way. Full article
(This article belongs to the Section Machine Design and Theory)
22 pages, 1788 KiB  
Article
A Combination Positioning Method for Boom-Type Roadheaders Based on Binocular Vision and Inertial Navigation
by Jiameng Cheng, Dongjie Wang, Jiming Liu, Pengjiang Wang, Weixiong Zheng, Rui Li and Miao Wu
Machines 2025, 13(2), 128; https://doi.org/10.3390/machines13020128 (registering DOI) - 8 Feb 2025
Viewed by 112
Abstract
A positioning method for a roadheader based on fiber-optic strap-down inertial navigation and binocular vision is proposed to address the issue of low measurement accuracy of the mining machine position caused by single-sensor methods in underground coal mines. A vision system for the [...] Read more.
A positioning method for a roadheader based on fiber-optic strap-down inertial navigation and binocular vision is proposed to address the issue of low measurement accuracy of the mining machine position caused by single-sensor methods in underground coal mines. A vision system for the mining machine position is constructed based on the four-point target fixed on the body of the roadheader, and the position and attitude information of the roadheader are obtained by combining the inertial navigation on the body. To deal with the problem of position detection inaccuracies caused by the accumulation of errors in inertial navigation measurements over time and disturbances from body vibrations to the combined positioning system, an Adaptive Derivative Unscented Kalman Filtering (ADUKF) algorithm is proposed, which can suppress the impact of process variance uncertainties on the filtering. The simulation results demonstrate that, compared to the Unscented Kalman Filtering algorithm, the position errors in the three directions are reduced by 20%, 20.68%, and 28.57%, respectively. Experiments demonstrate that the method can compensate for the limitations of single-measurement methods and meet the positioning accuracy requirements for underground mining standards. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
14 pages, 15719 KiB  
Article
Comprehensive Analysis of the Output Characteristics of Flow Field in Turbodrill Motor
by Wei Li, Fulu Chen, Mengyu Cao, Tianchi Ma, Wangluo Ning, Mingxiu Zhang, Tiansu He and Xu Wang
Machines 2025, 13(2), 127; https://doi.org/10.3390/machines13020127 (registering DOI) - 8 Feb 2025
Viewed by 151
Abstract
Turbodrills are extensively utilized within the oilfield development industry. In order to enhance the performance output of turbodrills, a novel stator and rotor structure has been conceptualized. Fluent 19.0 numerical simulation software was employed to ascertain the output characteristics of the rotor within [...] Read more.
Turbodrills are extensively utilized within the oilfield development industry. In order to enhance the performance output of turbodrills, a novel stator and rotor structure has been conceptualized. Fluent 19.0 numerical simulation software was employed to ascertain the output characteristics of the rotor within the flow field. The drilling engine output performance was the subject of a qualitative study, which was conducted using the drilling mud pump test equipment during drilling. Furthermore, a speed torque meter measurement system was designed to quantitatively analyze the output torque and speed performance of the prototype. The results show that: ① Through the numerical simulation method, it is verified that the new structural rotor has the output performance of a conventional rotor. ② Comparing the numerical solution and the test value, it can be seen that the relative error value is within 4.3%, indicating that the numerical simulation has a certain accuracy. ③ When the inlet displacement is 30 L/s and the speed is 1400 r/min, the maximum value of the numerical solution of the output torque of a single rotor group is 12.45 N/m. When the inlet displacement increases from 18 L/s to 30 L/s, the maximum torque numerical solution increases from 10.78 N/m to 27.44 N/m. Full article
(This article belongs to the Section Turbomachinery)
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18 pages, 3271 KiB  
Article
GES-YOLO: A Light-Weight and Efficient Method for Conveyor Belt Deviation Detection in Mining Environments
by Hongwei Wang, Ziming Kou and Yandong Wang
Machines 2025, 13(2), 126; https://doi.org/10.3390/machines13020126 (registering DOI) - 8 Feb 2025
Viewed by 165
Abstract
Conveyor belt deviation is one of the most common failures in belt conveyors. To address issues such as the high computational complexity, large number of parameters, long inference time, and difficulty in feature extraction of existing conveyor belt deviation detection models, we propose [...] Read more.
Conveyor belt deviation is one of the most common failures in belt conveyors. To address issues such as the high computational complexity, large number of parameters, long inference time, and difficulty in feature extraction of existing conveyor belt deviation detection models, we propose a GES-YOLO algorithm for detecting deviation in mining belt conveyors, based on an improved YOLOv8s model. The core of this algorithm is to enhance the model’s ability to extract features in complex scenarios, thereby improving the detection efficiency. Specifically, to improve real-time detection capabilities, we introduce the Groupwise Separable Convolution (GSConv) module. Additionally, by analyzing scene features, we remove the large object detection layer, which enhances the detection speed while maintaining the feature extraction capability. Furthermore, to strengthen feature perception under low-light conditions, we introduce the Efficient Multi-Scale Attention Mechanism (EMA), allowing the model to obtain more robust features. Finally, to improve the detection capability for small objects such as conveyor rollers, we introduce the Scaled Intersection over Union (SIoU) loss function, enabling the algorithm to sensitively detect rollers and provide a precise localization for deviation detection. The experimental results show that the GES-YOLO significantly improves the detection performance in complex environments such as high-noise and low-illumination conditions in coal mines. Compared to the baseline YOLOv8s model, GES-YOLO’s [email protected] and [email protected]:0.95 increase by 1.5% and 2.3%, respectively, while the model’s parameter count and computational complexity decrease by 38.2% and 10.5%, respectively. The Frames Per Second (FPS) of the average detection speed reaches 63.62. This demonstrates that GES-YOLO achieves a good balance between detection accuracy and inference speed, with excellent accuracy, robustness, and industrial application potential. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
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29 pages, 4034 KiB  
Review
Power Transformer Prognostics and Health Management Using Machine Learning: A Review and Future Directions
by Ryad Zemouri
Machines 2025, 13(2), 125; https://doi.org/10.3390/machines13020125 (registering DOI) - 7 Feb 2025
Viewed by 243
Abstract
Power transformers (PTs) play a vital role in the electrical power system. Assessing their health to predict their remaining useful life is essential to optimise maintenance. Scheduling the right maintenance for the right equipment at the right time is the ultimate goal of [...] Read more.
Power transformers (PTs) play a vital role in the electrical power system. Assessing their health to predict their remaining useful life is essential to optimise maintenance. Scheduling the right maintenance for the right equipment at the right time is the ultimate goal of any power system utility. Optimal maintenance has a number of benefits: human and social, by limiting sudden service interruptions, and economic, due to the direct and indirect costs of unscheduled downtime. PT now produces large amounts of easily accessible data due to the increasing use of IoT, sensors, and connectivity between physical assets. As a result, power transformer prognostics and health management (PT-PHM) methods are increasingly moving towards artificial intelligence (AI) techniques, with several hundreds of scientific papers published on the topic of PT-PHM using AI techniques. On the other hand, the world of AI is undergoing a new evolution towards a third generation of AI models: large-scale foundation models. What is the current state of research in PT-PHM? What are the trends and challenges in AI and where do we need to go for power transformer prognostics and health management? This paper provides a comprehensive review of the state of the art in PT-PHM by analysing more than 200 papers, mostly published in scientific journals. Some elements to guide PT-PHM research are given at the end of the document. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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19 pages, 962 KiB  
Article
Analysis of Stainless-Steel Tape Dynamic Behavior and Its Impact on Raster Scale Formation Accuracy
by Donatas Gurauskis, Albinas Kasparaitis, Edgar Sokolovskij, Jonas Matijošius and Artūras Kilikevičius
Machines 2025, 13(2), 124; https://doi.org/10.3390/machines13020124 - 7 Feb 2025
Viewed by 146
Abstract
The formation of raster structures on stainless-steel tapes requires high-precision mechatronic systems to ensure accuracy and stability during the process. This article gives a thorough look at a redesigned precise mechatronic system that can make coded or raster linear scales using a dynamic [...] Read more.
The formation of raster structures on stainless-steel tapes requires high-precision mechatronic systems to ensure accuracy and stability during the process. This article gives a thorough look at a redesigned precise mechatronic system that can make coded or raster linear scales using a dynamic laser process. These scales are critical components in linear measuring systems, such as optical encoders, where accuracy and reliability are paramount. One critical challenge is maintaining precise tape dynamics to mitigate errors caused by slippage at the tape-roller interface and mechanical vibrations. The main goal of this study is to look at these changing behaviors in a redesigned tape displacement measurement unit. Unlike older models, this one does not use a pneumatic roller system; instead, the tape drives the measuring roller directly. Experiments show that the new design greatly lowers errors caused by slippage and vibration, which makes it easier for the tape to move in sync with the laser activation. Additionally, the updated system exhibits enhanced performance in terms of stability, achieving higher accuracy of the raster structure compared to the previous design. These findings underscore the importance of dynamic analysis in optimizing tape displacement measurement units for high-precision raster formation processes. Full article
(This article belongs to the Section Robotics, Mechatronics and Intelligent Machines)
27 pages, 4076 KiB  
Article
Horizontal and Vertical Coordinated Control of Three-Axis Heavy Vehicles
by Lanchun Zhang, Fei Huang, Hao Cui, Yaqi Wang and Lin Yang
Machines 2025, 13(2), 123; https://doi.org/10.3390/machines13020123 - 7 Feb 2025
Viewed by 246
Abstract
In order to coordinate the transverse motion control and longitudinal motion control in the tracking control process and ensure the yaw stability and roll stability in the tracking process, a transverse and longitudinal coordinated control method of three-axis heavy vehicles is designed based [...] Read more.
In order to coordinate the transverse motion control and longitudinal motion control in the tracking control process and ensure the yaw stability and roll stability in the tracking process, a transverse and longitudinal coordinated control method of three-axis heavy vehicles is designed based on model predictive control. The lateral motion controller is designed based on the phase plane method. The upper controller calculates the front wheel angle and additional yaw moment, which ensures the yaw stability while tracking the vehicle. The lower controller calculates the driving force and braking force of the three-axis heavy vehicle. The velocity planning method is designed with the coupling point of longitudinal velocity to coordinate the lateral and longitudinal motion controllers and prevent vehicle rollover. By building the vehicle model in Trucksim (2016.1) and establishing the horizontal and vertical coordination control in Matlab (R2016b), the designed horizontal and vertical coordination control method is simulated and verified. The simulation results show that the designed method can accurately track the reference trajectory while ensuring the yaw stability and roll stability of the three-axis heavy vehicle. Full article
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25 pages, 9755 KiB  
Article
Marker-Based Safety Functionality for Human–Robot Collaboration Tasks by Means of Eye-Tracking Glasses
by Enrico Masi, Nhu Toan Nguyen, Eugenio Monari, Marcello Valori and Rocco Vertechy
Machines 2025, 13(2), 122; https://doi.org/10.3390/machines13020122 - 6 Feb 2025
Viewed by 282
Abstract
Human–robot collaboration (HRC) remains an increasingly growing trend in the robotics research field. Despite the widespread usage of collaborative robots on the market, several safety issues still need to be addressed to develop industry-ready applications exploiting the full potential of the technology. This [...] Read more.
Human–robot collaboration (HRC) remains an increasingly growing trend in the robotics research field. Despite the widespread usage of collaborative robots on the market, several safety issues still need to be addressed to develop industry-ready applications exploiting the full potential of the technology. This paper focuses on hand-guiding applications, proposing an approach based on a wearable device to reduce the risk related to operator fatigue or distraction. The methodology aims at ensuring operator’s attention during the hand guidance of a robot end effector in order to avoid injuries. This goal is achieved by detecting a region of interest (ROI) and checking that the gaze of the operator is kept within this area by means of a pair of eye-tracking glasses (Pupil Labs Neon, Berlin, Germany). The detection of the ROI is obtained primarily by the tracking camera of the glasses, acquiring the position of predefined ArUco markers, thus obtaining the corresponding contour area. In case of the misdetection of one or more markers, their position is estimated through the optical flow methodology. The performance of the proposed system is initially assessed with a motorized test bench simulating the rotation of operator’s head in a repeatable way and then in an HRC scenario used as case study. The tests show that the system can effectively identify a planar ROI in the context of a HRC application in real time. Full article
(This article belongs to the Section Automation and Control Systems)
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14 pages, 2798 KiB  
Article
Investigation of Engine Lubrication Oil Quality Using a Support Vector Machine and Electronic Nose
by Ali Adelkhani and Ehsan Daneshkhah
Machines 2025, 13(2), 121; https://doi.org/10.3390/machines13020121 - 6 Feb 2025
Viewed by 291
Abstract
Monitoring the quality of engine oil improves engine efficiency and reduces engine maintenance costs. Several methods have been proposed for this purpose; however, most of them take too long to test oil quality. This paper introduces a fast, simple, and accurate method to [...] Read more.
Monitoring the quality of engine oil improves engine efficiency and reduces engine maintenance costs. Several methods have been proposed for this purpose; however, most of them take too long to test oil quality. This paper introduces a fast, simple, and accurate method to determine oil quality using an electronic nose and artificial intelligence. The TU5 engine and 10-40W “Behran Super Pishtaz” engine oil were used in the experiments. Tests were conducted at six different quality levels. Oil properties such as viscosity, density, flash point, and freezing point were measured at each level. Additionally, oil smell signals were recorded using an olfactory machine at these quality levels. The fraction method was employed to adjust the sensors’ responses. Five statistical features were extracted from each signal, and these features were used to train and test a support vector machine (SVM) for classifying oil quality using the five-fold cross-validation method. The results indicated a statistically significant change in viscosity and density with variations in oil quality. The density increased as the quality decreased. Viscosity, however, initially decreased and then increased at later stages. An analysis of the sensory outputs revealed that changes in oil quality also affected these outputs, with the most pronounced sensitivity observed in the MQ135 and MQ138 sensors. The final accuracies of the SVM in classifying oil quality were 68.22%, 85.86%, and 95.44% for linear, radial basis function (RBF), and polynomial kernels, respectively. The SVM sensitivities for oil qualities A, B, C, D, E, and F were 97.99%, 97.37%, 95.51%, 92.67%, 94.48%, and 94.59%, respectively. Full article
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25 pages, 1914 KiB  
Article
Real-Time Modeling of Static, Dynamic and Mixed Eccentricity in Permanent Magnet Synchronous Machines
by Ramón Pérez, Jérôme Cros and Mathieu Picard
Machines 2025, 13(2), 120; https://doi.org/10.3390/machines13020120 - 4 Feb 2025
Viewed by 366
Abstract
Eccentricity faults are one of the main causes that significantly affect the performance of permanent magnet synchronous machines (PMSMs). Monitoring eccentricity in real time could prevent failures by adapting operation conditions and maintenance schedule when early signs of deterioration are detected. This article [...] Read more.
Eccentricity faults are one of the main causes that significantly affect the performance of permanent magnet synchronous machines (PMSMs). Monitoring eccentricity in real time could prevent failures by adapting operation conditions and maintenance schedule when early signs of deterioration are detected. This article proposes making a circuit-type model of a permanent magnet machine with an easily configurable eccentricity for simulations and real-time analysis of signals under different operating conditions. The basis for the construction of the circuit model will be the simulation of the PMSM with 49 different coordinates of the rotor center, using the finite element analysis (FEA). The presence of eccentricity causes a variation in the inductances, the no-load flux and the expansion torque depending on the position of the rotor. The model proposes the use of bilinear interpolation (BI) to estimate the inductance matrix, the no-load flux vector captured by the stator winding and the cogging torque due to the presence of the magnets in the rotor, all of them for each rotor position. The validation is done by comparing the precision in the results of the machine’s self-inductances, the torque and the voltage waveform at the PMSM terminals and the static torque of the PMSM. The circuit model results are validated in two ways: (1) through experimental simulation, comparing the same results obtained using FEA and (2) through practical experimentation, producing a dynamic eccentricity in the machine of 0.3 mm. The results show that the proposed model is capable of accurately reproducing the behavior of the PMSM against eccentricity faults and presents computational time savings close to 99% compared to the response time obtained using FEA. This rapid PMSM model, parameterizable according to the degree of eccentricity, is the basis for the real-time simulation of the main machine waveforms, such as voltage, current and torque. Full article
(This article belongs to the Special Issue Fault Diagnostics and Fault Tolerance of Synchronous Electric Drives)
21 pages, 2719 KiB  
Article
Fuzzy Flocking Control for Multi-Agents Trapped in Dynamic Equilibrium Under Multiple Obstacles
by Weibin Liang, Xiyan Sun, Yuanfa Ji, Xinyi Liu, Jianhui Wu and Zhongxi He
Machines 2025, 13(2), 119; https://doi.org/10.3390/machines13020119 - 4 Feb 2025
Viewed by 236
Abstract
The Olfati-Saber flocking (OSF) algorithm is widely used in multi-agent flocking control due to its simplicity and effectiveness. However, this algorithm is prone to trapping multi-agents in dynamic equilibrium under multiple obstacles, and dynamic equilibrium is a key technical issue that needs to [...] Read more.
The Olfati-Saber flocking (OSF) algorithm is widely used in multi-agent flocking control due to its simplicity and effectiveness. However, this algorithm is prone to trapping multi-agents in dynamic equilibrium under multiple obstacles, and dynamic equilibrium is a key technical issue that needs to be addressed in multi-agent flocking control. To overcome this problem, we propose a dynamic equilibrium judgment rule and design a fuzzy flocking control (FFC) algorithm. In this algorithm, the expected velocity is divided into fuzzy expected velocity and projected expected velocity. The fuzzy expected velocity is designed to make the agent escape from the dynamic equilibrium, and the projected expected velocity is designed to tow the agent, bypassing the obstacles. Meanwhile, the sensing radius of the agent is divided into four subregions, and a nonnegative subsection function is designed to adjust the attractive/repulsive potentials in these subregions. In addition, the virtual leader is designed to guide the agent in achieving group goal following. Finally, the experimental results show that multi-agents can escape from dynamic equilibrium and bypass obstacles at a faster velocity, and the minimum distance between them is consistently greater than the minimum safe distance under complex environments in the proposed algorithm. Full article
(This article belongs to the Section Automation and Control Systems)
25 pages, 979 KiB  
Article
Modeling and Analysis of the Turning Performance of an Articulated Tracked Vehicle That Considers the Inter-Unit Coupling Forces
by Ningyi Li, Xixia Liu, Hongqian Chen and Yu Zhang
Machines 2025, 13(2), 118; https://doi.org/10.3390/machines13020118 - 4 Feb 2025
Viewed by 206
Abstract
The interactions between ground reaction forces and inter-unit coupling forces add complexity to the study of the turning motion of articulated tracked vehicles (ATVs). To accurately analyze the turning performance of an ATV, this study developed a steady-state steering model that captures the [...] Read more.
The interactions between ground reaction forces and inter-unit coupling forces add complexity to the study of the turning motion of articulated tracked vehicles (ATVs). To accurately analyze the turning performance of an ATV, this study developed a steady-state steering model that captures the effects of load transfer caused by coupling and centrifugal forces. First, based on vehicle kinematics under skidding conditions, formulas that incorporate parameters for the lateral track displacement were derived to calculate the turning radii of the front and rear units. Then, the track traction forces and turning resistance moments were calculated using the shear stress–shear displacement relationship. Finally, a steady-state steering model on firm ground conditions was developed for the vehicle according to mechanical equilibrium conditions, and the model was validated using previously reported data. Analyses of the results revealed that the coupling forces provided the driving moments for the turning motion by the transfer of the centrifugal and ground reaction forces that acted on the front and rear units. During turning, the rear unit had a larger radius than the front unit, and the minimum swept radius of the ATV was dependent upon the radius of the outer track trajectory of the rear unit. Specifically, at a speed of 3.1 m/s and a steering angle of 35°, the vehicle exhibited a minimum outer swept radius of 8.8 m, requiring a turning space equivalent to a 3.1-meter-wide road. The required turning space increased as both the steering angle and speed increased. Full article
(This article belongs to the Section Vehicle Engineering)
25 pages, 48394 KiB  
Article
Experimental Research and Significance Analysis of Advanced Interpolation Methods for Optimizing System State Items and Processing Parameters
by Chunlei Tian, Yan Cao, Tian Chen and Tianlong Yuan
Machines 2025, 13(2), 117; https://doi.org/10.3390/machines13020117 - 3 Feb 2025
Viewed by 348
Abstract
The Finite-Difference Method (FDM) plays a pivotal role in the field of stability prediction, particularly in the modeling and stability analysis of cutting process dynamics. However, traditional approaches to optimizing the FDM often treat system state terms and time-delay terms as a monolithic [...] Read more.
The Finite-Difference Method (FDM) plays a pivotal role in the field of stability prediction, particularly in the modeling and stability analysis of cutting process dynamics. However, traditional approaches to optimizing the FDM often treat system state terms and time-delay terms as a monolithic entity, failing to explicitly distinguish between them, which leads to a lack of specificity in selecting optimization targets. In this study, an innovative approach is introduced by incorporating the third-order Newton interpolation method and the fourth-order Hermite interpolation method. By comparing the computational accuracy and convergence speed, it is found that the 3N-FDM (third-order Newton Finite-Difference Method) exhibits superior overall performance, and it is clearly pointed out that increasing the order does not always result in better outcomes. Additionally, this study selects different discretization numbers, denoted as m, for comparative analysis to thoroughly evaluate their impact on computational accuracy. Experimental validation demonstrates the high accuracy of the 3N-FDM. Through a one-way ANOVA (analysis of variance) of tool wear and workpiece surface roughness, it is revealed that changes in system state terms have the most significant impact on the feed rate f, followed by the cutting depth ap, and finally the spindle speed n. Based on the experimental results and analysis mentioned above, this study concludes that optimizing system state terms can more effectively explore the combined influences of processing parameters on processing quality, production efficiency, and tool wear. Full article
(This article belongs to the Section Advanced Manufacturing)
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28 pages, 2591 KiB  
Article
Dynamics Modeling and Suspension Parameters Optimization of Vehicle System Based on Reduced Multibody System Transfer Matrix Method
by Shaoheng Hu, Xiaoting Rui, Junjie Gu and Xizhe Zhang
Machines 2025, 13(2), 116; https://doi.org/10.3390/machines13020116 - 2 Feb 2025
Viewed by 351
Abstract
This study introduces an innovative vehicle-modeling framework based on the Reduced Multibody System Transfer Matrix Method, incorporating wheel–ground contact and friction to analyze dynamic performance metrics, including vertical acceleration, suspension deflection, and angular acceleration. The model is applied to simulate vehicle behavior at [...] Read more.
This study introduces an innovative vehicle-modeling framework based on the Reduced Multibody System Transfer Matrix Method, incorporating wheel–ground contact and friction to analyze dynamic performance metrics, including vertical acceleration, suspension deflection, and angular acceleration. The model is applied to simulate vehicle behavior at 40 km/h on Class D road conditions. To enhance dynamic characteristics, suspension parameters were optimized using the NSGA-II algorithm. The optimization process achieved significant reductions in vertical acceleration (24.12%), suspension deflection (25.98%), and angular acceleration (4.93%). The Pareto frontier facilitated the selection of a representative solution that balances smoothness, stability, and suspension performance. Frequency, PSD, and RMS analyses were performed under different road conditions and speeds to verify the robustness of the optimization results. The application of the transfer matrix method is extended to vehicle suspension modeling and optimization, offering valuable insights into improving ride comfort and stability. Additionally, it highlights the effectiveness of advanced multi-objective optimization techniques in improving vehicle dynamics and provides a robust methodology for practical applications. Full article
(This article belongs to the Section Vehicle Engineering)
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13 pages, 9006 KiB  
Article
Tool Condition Monitoring Model Based on DAE–SVR
by Xiaoning Sun, Zhifeng Yang, Maojin Xia, Min Xia, Changfu Liu, Yang Zhou and Yuquan Guo
Machines 2025, 13(2), 115; https://doi.org/10.3390/machines13020115 - 1 Feb 2025
Viewed by 310
Abstract
Cutting tools are executive components in metal processing, and tool wear directly affects the quality of the workpiece and processing efficiency; monitoring the change in its state is crucial to avoid accidents and ensure the safety of workers. The traditional monitoring model cannot [...] Read more.
Cutting tools are executive components in metal processing, and tool wear directly affects the quality of the workpiece and processing efficiency; monitoring the change in its state is crucial to avoid accidents and ensure the safety of workers. The traditional monitoring model cannot compress a large amount of cutting data effectively, failing to obtain reliable feature data, and there are some defects in generalization ability and monitoring accuracy. For this purpose, this article takes milling cutters as the research object, and it integrates signals from force sensors, vibration sensors, and acoustic emission sensors, combining the advantages of the denoising autoencoder (DAE) model in data compression and the high monitoring accuracy of the support vector regression (SVR) model, to establish a tool wear monitoring model based on DAE–SVR. The results show that compared with traditional DAE and SVR models in multiple datasets, the maximum improvement in monitoring performance (MAE) is 43.58%. Full article
(This article belongs to the Section Machines Testing and Maintenance)
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29 pages, 2886 KiB  
Article
Design and Discrete Element (DEM) Simulation Analysis of Grassland Ecological Cleaning and Restoration Vehicle
by Lvfa Yin, Anfu Guo, Chang Liu, Minghui Guo, Dechao Yang, Xianxiang Gao and Hailong Wu
Machines 2025, 13(2), 114; https://doi.org/10.3390/machines13020114 - 30 Jan 2025
Viewed by 322
Abstract
To reduce the weight of the grassland ecological restoration vehicle disk brush, force analysis and topology optimization are carried out to reduce the weight of the disk brush by 55.43%. Then, the study found that the vehicle speed and the rotational speed of [...] Read more.
To reduce the weight of the grassland ecological restoration vehicle disk brush, force analysis and topology optimization are carried out to reduce the weight of the disk brush by 55.43%. Then, the study found that the vehicle speed and the rotational speed of the disk brush have an effect on the trajectory of garbage throwing, and the relationship between the two needs to be coordinated. The sweeping effect works best when the speed ratio coefficient is greater than 1.826, which can be found by matching the motion trajectory equation with the speed ratio coefficient λ. Based on the discrete element method (DEM), it is verified that when the rotational speed is 90 r/min and the vehicle speed is 10 km/h, the sweeping effect is the best, and the influence on plants is minimized. Finally, the seeding effect of grass seeds was verified by a three-factor three-level orthogonal experiment. The results showed that high rotational speed and multiple slots could reduce the row spacing of seeding, while higher speed increased the row spacing of seeding. When the rotational speed of the seed-displacement disk was 50 r/min, the number of slots was 24, and the vehicle speed was 15 km/h, the seed displacement reached the maximum, and the row spacing was in line with the reasonable seeding requirements of ryegrass. The experimental results provide technical support for similar grassland cleaning and restoration vehicles in the future. Full article
(This article belongs to the Section Machine Design and Theory)
33 pages, 11404 KiB  
Review
Review on Key Development of Magnetic Bearings
by Tong Wu and Weiyu Zhang
Machines 2025, 13(2), 113; https://doi.org/10.3390/machines13020113 - 30 Jan 2025
Viewed by 389
Abstract
A magnetic suspension bearing is a device that suspends the rotating shaft in a balanced position by magnetic force, thereby eliminating the friction between the rotor and the stator. Different from traditional bearing support methods, magnetic bearings show significant advantages in terms of [...] Read more.
A magnetic suspension bearing is a device that suspends the rotating shaft in a balanced position by magnetic force, thereby eliminating the friction between the rotor and the stator. Different from traditional bearing support methods, magnetic bearings show significant advantages in terms of speed, accuracy, and loss. Because there is no contact, magnetic bearings enable high-speed operation, precise control, and zero friction. Magnetic bearings, with their excellent performance, are widely applied in fields such as industrial production, flywheel energy storage, and aerospace. However, with the continuous growth of the demand for high-performance bearings and the deepening of the concept of low-carbon and environmental protection, breakthroughs in the key technologies of magnetic bearings are urgently needed. In this paper, relevant research on magnetic bearings is summarized. Magnetic bearings are classified according to the different ways in which they generate suspension forces. Research on the topological structure design, mathematical modeling, and control strategies of the magnetic bearing system is covered. The aim is to provide readers and researchers with a comprehensive overview of the key technologies of magnetic bearings from a new perspective. Full article
(This article belongs to the Section Electromechanical Energy Conversion Systems)
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23 pages, 11041 KiB  
Article
Event Knowledge Graph for a Knowledge-Based Design Process Model for Additive Manufacturing
by Chen Guohui, Auwal Haruna, Chen Youze, Li Lunyong, Khandaker Noman, Yongbo Li and K. Eliker
Machines 2025, 13(2), 112; https://doi.org/10.3390/machines13020112 - 30 Jan 2025
Viewed by 299
Abstract
Additive manufacturing (AM) technology is gaining acceptance as a strategic manufacturing technique for allowing new product development. Due to ongoing process improvement, design for AM (DFAM) has become a major issue in harnessing AM’s production and development possibilities to achieve design freedom. The [...] Read more.
Additive manufacturing (AM) technology is gaining acceptance as a strategic manufacturing technique for allowing new product development. Due to ongoing process improvement, design for AM (DFAM) has become a major issue in harnessing AM’s production and development possibilities to achieve design freedom. The classical design process model does not encompass all the knowledge available to take advantage of design freedom. Therefore, a conceptual and in-depth analysis of design alternatives is necessary to determine the manufacturing process. As a result, this research proposed a design process model for a DFAM to attain design freedom with a unique approach and resource selection steps for fused deposition modeling (FDM) that uses an information model based on evolving knowledge and addressing the challenges. The proposed design process model uses an event knowledge graph (EKG) to outline the product manufacturability from the perspective of DFAM limitations. Event-based knowledge representation provides causality information for knowledge-based reasoning in causality analysis tasks. A relationship-aware mechanism is then used to express events on the graph that are directed from entities to occurrences to efficiently extract the most relevant details. Thus, this implements a step-by-step approach to process and resource specifications during the design stage. Consequently, it offers a comprehensive learning approach for establishing and modeling intrinsic relationships to attain flexibility and design freedom. The efficacy and feasibility of the proposed approach are verified by using an application case study of an intake system based on the airflow sensing rate and controls how much air is fed into the engine. Full article
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31 pages, 4692 KiB  
Review
Active Disturbance Rejection Control—New Trends in Agricultural Cybernetics in the Future: A Comprehensive Review
by Yu-Hao Tu, Rui-Feng Wang and Wen-Hao Su
Machines 2025, 13(2), 111; https://doi.org/10.3390/machines13020111 - 29 Jan 2025
Viewed by 374
Abstract
With the development of smart and precision agriculture, new challenges have emerged in terms of response speed and adaptability in agricultural equipment control. Active Disturbance Rejection Control (ADRC), an advanced control strategy known for its strong robustness and disturbance rejection capabilities, has demonstrated [...] Read more.
With the development of smart and precision agriculture, new challenges have emerged in terms of response speed and adaptability in agricultural equipment control. Active Disturbance Rejection Control (ADRC), an advanced control strategy known for its strong robustness and disturbance rejection capabilities, has demonstrated exceptional performance in various fields, such as aerospace, healthcare, and military applications. Therefore, investigating the application of ADRC in agricultural control systems is of great significance. This review focuses on the fundamental principles of ADRC and its applications in agriculture, exploring its potential use and achievements in precision agriculture management, intelligent agricultural control, and other agricultural control sectors. These include the control of agricultural machinery, field navigation and trajectory tracking, agricultural production processes, as well as fisheries and greenhouse management in various agricultural scenarios. Additionally, this paper summarizes the integration of ADRC with other control technologies (e.g., LADRC, SMC) in agricultural applications and discusses the advantages and limitations of ADRC in the aforementioned areas. Furthermore, the challenges, development trends, and future research directions of ADRC in agricultural applications are examined to provide a reference for its future development. Full article
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22 pages, 5865 KiB  
Article
Dynamic Performance Analysis and Fault Ride-Through Enhancement by a Modified Fault Current Protection Scheme of a Grid-Connected Doubly Fed Induction Generator
by Rameez Akbar Talani, Ghulam Sarwar Kaloi, Aamir Ali, Muhammad Ali Bijarani, Ghulam Abbas, Mohammed Hatatah, Paolo Mercorelli and Ezzeddine Touti
Machines 2025, 13(2), 110; https://doi.org/10.3390/machines13020110 - 29 Jan 2025
Viewed by 331
Abstract
With the increase in reliance on doubly fed induction generator-based wind energy conversion systems (DFIG-WECSs), extracting maximum power from wind energy and enhancing fault ride-through (FRT) techniques meeting the grid code requirements is the foremost concern. This paper proposes a modified control scheme [...] Read more.
With the increase in reliance on doubly fed induction generator-based wind energy conversion systems (DFIG-WECSs), extracting maximum power from wind energy and enhancing fault ride-through (FRT) techniques meeting the grid code requirements is the foremost concern. This paper proposes a modified control scheme that operates in normal running conditions and during faults as a dual mode. The proposed control scheme operates in a coordinated wind speed estimation-based maximum power point tracking (WSE-MPPT) mode during normal running conditions to extract maximum power from wind energy and enhances the crowbar rotor active impedance-based FRT mode during faults. The proposed technique controls the rotor side converter (RSC) parameters during faults by limiting the transient surge in the rotor and stator currents. In this study, the transient behavior of the proposed technique is analyzed under a three-phase symmetrical fault with a severe voltage dip, and it is observed that, when the fault is over and the RSC is activated and connected to the system, a large inrush current is produced with transient oscillations; the proposed scheme suppresses this post-fault inrush current and limits the transient oscillation. During the FRT operating mode under a symmetrical fault, the simulation results of the proposed technique are validated by the conventional crowbar strategy. In contrast, during the WSE-MPPT operating mode under normal running conditions, a smooth achievement of system parameters after starting the inrush period to a steady state at fixed wind speed is observed. Full article
23 pages, 5221 KiB  
Article
Digital Twin-Based Prediction and Optimization for Dynamic Supply Chain Management
by Dong-Hun Kim, Goo-Young Kim and Sang Do Noh
Machines 2025, 13(2), 109; https://doi.org/10.3390/machines13020109 - 29 Jan 2025
Viewed by 513
Abstract
Manufacturing supply chains are becoming increasingly complex due to geopolitical issues, globalization, and market demand uncertainties. These challenges lead to logistics disruptions, inventory shortages, and interruptions in raw materials and spare parts production, resulting in delayed delivery, reduced market share, and lower customer [...] Read more.
Manufacturing supply chains are becoming increasingly complex due to geopolitical issues, globalization, and market demand uncertainties. These challenges lead to logistics disruptions, inventory shortages, and interruptions in raw materials and spare parts production, resulting in delayed delivery, reduced market share, and lower customer satisfaction. Effective supply chain management is critical for improving operational efficiency and competitiveness. This paper proposes a supply chain digital twin methodology to enhance operational efficiency through real-time monitoring, analysis, and response to disruptions. This methodology defines a supply chain digital twin system architecture and outlines the operational process of digital twin applications. It introduces two key modules: a digital twin module for prediction and monitoring and an optimization module for determining the optimal movement of products. These modules are integrated to align digital simulations with real-world supply chain operations. The proposed approach is validated through a case study of an automobile body production company’s supply chain, demonstrating its effectiveness in reducing inventory and logistics costs while providing countermeasures for abnormal situations. Full article
(This article belongs to the Section Industrial Systems)
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34 pages, 16520 KiB  
Article
Enhanced Non-Destructive Testing of Small Wind Turbine Blades Using Infrared Thermography
by Majid Memari, Mohammad Shekaramiz, Mohammad A. S. Masoum and Abdennour C. Seibi
Machines 2025, 13(2), 108; https://doi.org/10.3390/machines13020108 - 29 Jan 2025
Viewed by 386
Abstract
This study presents a foundational step in a broader initiative aimed at leveraging thermal imaging technology to enhance wind turbine maintenance, particularly focusing on the challenges of detecting defects and object localization in small wind turbine blades. Serving as a preliminary experiment, this [...] Read more.
This study presents a foundational step in a broader initiative aimed at leveraging thermal imaging technology to enhance wind turbine maintenance, particularly focusing on the challenges of detecting defects and object localization in small wind turbine blades. Serving as a preliminary experiment, this research project tested methodologies and technologies on a smaller scale before advancing to more complex applications involving large, operational wind turbines using drone-mounted cameras. Utilizing thermal cameras suitable for both handheld and drone use, alongside advanced image processing applications, we navigated the significant challenge of acquiring high-quality thermal images to detect small defects. This required a concentrated analysis of a select subset of data and a methodological shift towards object detection and localization using the You Only Look Once (YOLO) model versions 8 and 9. This effort not only paves the way for applying these techniques to larger-scale turbines but also contributes to the ongoing development of an integrated maintenance strategy in the wind energy sector. Highlighting the critical impact of environmental conditions on thermal imaging, our research underscores the importance of continued exploration in this field, especially in enhancing object localization techniques for the future drone-based maintenance of operational wind turbine blades (WTBs). Full article
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29 pages, 4380 KiB  
Article
The Space Phasors Theory and the Conditions for the Correct Decoupling of Multiphase Machines
by Luis Serrano-Iribarnegaray and Jorge Bonet-Jara
Machines 2025, 13(2), 107; https://doi.org/10.3390/machines13020107 - 29 Jan 2025
Viewed by 340
Abstract
This paper first analyzes the general statements accepted in the technical literature concerning the complete dynamic decoupling of constant air-gap multiphase machines with space harmonics (usually resorting to the instantaneous symmetrical components, ISCs) and shows that they are not correct, since they only [...] Read more.
This paper first analyzes the general statements accepted in the technical literature concerning the complete dynamic decoupling of constant air-gap multiphase machines with space harmonics (usually resorting to the instantaneous symmetrical components, ISCs) and shows that they are not correct, since they only hold (and only with good approximation) for the particular case of converter-controlled machines. It then deduces in a rigorous theoretical way the correct conditions in all cases for both a precise and an approximate decoupling of multiphase machines and thereupon verifies them through numerous simulations. To do that, the Space Phasors Theory (SPhTh) is applied, whose true core, often unknown or misunderstood, is clearly explained. Preceding this point, the concept of the dynamic phasor of g sequence, which is a fundamental tool in the SPhTh, is introduced, and a necessary historical and critical review of the ISCs is undertaken. Full article
(This article belongs to the Section Electrical Machines and Drives)
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25 pages, 10925 KiB  
Article
The Secondary Lifting Performance of Crawler Crane Under Delay Coefficient Control Strategy
by Jin Zhang, Ranheng Du, Kuo Zhang, Yin Zhang, Ying Li and Xing Chen
Machines 2025, 13(2), 106; https://doi.org/10.3390/machines13020106 - 29 Jan 2025
Viewed by 324
Abstract
Crawler cranes are mobile lifting equipment used in the process of hoisting goods. After the initial lifting, the crane may need a secondary lift due to adjustments in the position or height of the load. Addressing the common issue of load slipping during [...] Read more.
Crawler cranes are mobile lifting equipment used in the process of hoisting goods. After the initial lifting, the crane may need a secondary lift due to adjustments in the position or height of the load. Addressing the common issue of load slipping during the secondary lift caused by hydraulic motor reversal, this study proposes a control strategy applicable to crawler crane secondary lifting. Initially establishing the dynamic characteristics of the secondary lift system, incorporating a delay coefficient, and matching motor pressure build-up with memory pressure, the strategy considers a variable pump input current control to identify the relationship between motor pressure build-up and brake release. Analyzing the dynamic characteristics of secondary lifting under different conditions, this study resolves the issue of hydraulic motor reversal during the second lift caused by heavy loads. The results of this study on crawler crane secondary lifting indicate that, when using a delay coefficient of 0.70 and releasing the brake, no slip phenomenon occurred during the secondary lift process under different load conditions, categorized as 200 tons, 600 tons, and 1000 tons. This ensures the stability and transition quality of the secondary lift, providing theoretical guidance for the control of the crawler crane secondary lifting. Full article
(This article belongs to the Section Machine Design and Theory)
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16 pages, 1111 KiB  
Article
Wear and Plasticity in Railway Turnout Crossings: A Fast Semi-Physical Model to Replace FE Simulations
by Hamed Davoodi Jooneghani, Kamil Sazgetdinov, Alexander Meierhofer, Stephan Scheriau, Uwe Ossberger, Gabor Müller and Klaus Six
Machines 2025, 13(2), 105; https://doi.org/10.3390/machines13020105 - 28 Jan 2025
Viewed by 469
Abstract
Severe changes in the profiles of the crossing nose are caused by large dynamic contact forces. To predict these forces as well as the profile evolution, the Whole System Model (WSM) was developed. However, it uses computationally expensive FE simulations. As a replacement, [...] Read more.
Severe changes in the profiles of the crossing nose are caused by large dynamic contact forces. To predict these forces as well as the profile evolution, the Whole System Model (WSM) was developed. However, it uses computationally expensive FE simulations. As a replacement, the semi-physical plasticity and wear model (SPPW) has been developed, thus majorly enhancing the overall performance of the WSM. The SPPW considers the influence of wear, plasticity, and wheel-profile-related effects. Its results have shown an overall good correlation with FE results, laboratory data for different materials, and field data from a real crossing. Due to the semi-physical nature of the model, the required computational time for the predictions was significantly reduced compared to FE simulations: minutes instead of weeks. The SPPW will be useful for time-efficient rail damage prediction, like wear and plastic deformation, and, as part of the WSM, contribute to a fast holistic track damage prognosis. Full article
(This article belongs to the Special Issue Wheel–Rail Contact: Mechanics, Wear and Analysis)
16 pages, 5811 KiB  
Article
Enhancing Spraying Performance with Active Stability Control in Multi-Link Mechanisms
by Naiyu Shi, He Li, Yongkang Yang, Hongliang Hua, Junhong Ye, Zheng Chen and Ting Xu
Machines 2025, 13(2), 104; https://doi.org/10.3390/machines13020104 - 28 Jan 2025
Viewed by 402
Abstract
This study proposes an active stability control method for the multi-link mechanism of spraying equipment to enhance its spraying performance. Traditional spraying operations typically focus on protecting only the tops of crops, whereas the multi-link mechanism can adjust the angle and position of [...] Read more.
This study proposes an active stability control method for the multi-link mechanism of spraying equipment to enhance its spraying performance. Traditional spraying operations typically focus on protecting only the tops of crops, whereas the multi-link mechanism can adjust the angle and position of the nozzles in coordination, achieving comprehensive protection for the crops. However, the characteristic of uneven output speed in the multi-link mechanism results in variations in the spraying amount at different positions. To address this issue, this study developed a method for actively adjusting the stability of the output end speed. First, a differential equation was established to relate the input speed to the output speed using vector methods, implicit function transformation to explicit functions, and regression analysis. The feasibility of this method was verified through simulations using MATLAB Simulink R2018a and Adams 2018. Prototype test results indicate that this speed adjustment method improved the stability of the output angular velocity, reducing the coverage rate variation between the upward, sideways, and downward of the leaves by 12.53% during the spraying process. Therefore, the method proposed in this study can enhance the uniformity of spraying, further improving the utilization of pesticides, which is beneficial for the green ecological sustainable development in the agricultural field. Additionally, this control method is also applicable to other types of link mechanisms, providing a reference for improving the output stability of link mechanisms. Full article
(This article belongs to the Section Machine Design and Theory)
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15 pages, 2342 KiB  
Article
Numerical Modeling and Optimization of Nomex Honeycomb Core Milling: Influence of Longitudinal and Longitudinal–Torsional Ultrasonic Vibrations
by Tarik Zarrouk, Mohammed Nouari and Hicham Bouali
Machines 2025, 13(2), 99; https://doi.org/10.3390/machines13020099 - 27 Jan 2025
Viewed by 344
Abstract
Nomex honeycomb structures (NHCs) have currently experienced significant development, mainly in the aeronautics, aerospace, marine, and automotive sectors. This expansion raises noteworthy challenges related to the improvement of machining excellence, necessitating the use of particular cutting tools and adapted techniques. With this in [...] Read more.
Nomex honeycomb structures (NHCs) have currently experienced significant development, mainly in the aeronautics, aerospace, marine, and automotive sectors. This expansion raises noteworthy challenges related to the improvement of machining excellence, necessitating the use of particular cutting tools and adapted techniques. With this in mind, experimental studies were conducted to analyze the specificities of Nomex honeycomb cores milling by integrating longitudinal ultrasonic vibrations along the cutting tool rotation axis (UCK). However, the high tool speed and the unreachability of the tool-workpiece interface complicate the direct observation of the cutting process. To overcome these challenges, a 3D numerical model was developed to simulate the milling of composite honeycomb structures by integrating longitudinal and longitudinal–torsional ultrasonic vibrations. This model was developed by Abaqus/Explicit software, version 2017. The obtained results indicate that the integration of longitudinal–torsional vibrations allows a reduction in cutting forces by up to 28%, a reduction in the accumulation of material in front of the cutting tool, with a maximum reduction of 30%, and an improvement in the quality of the machined surface. Full article
(This article belongs to the Special Issue Machine Tools for Precision Machining: Design, Control and Prospects)
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16 pages, 8593 KiB  
Article
Smart Machine Vision System to Improve Decision-Making on the Assembly Line
by Carlos Americo de Souza Silva and Edson Pacheco Paladini
Machines 2025, 13(2), 98; https://doi.org/10.3390/machines13020098 - 27 Jan 2025
Viewed by 489
Abstract
Technological advances in the production of printed circuit boards (PCBs) are increasing the number of components inserted on the surface. This has led the electronics industry to seek improvements in their inspection processes, often making it necessary to increase the level of automation [...] Read more.
Technological advances in the production of printed circuit boards (PCBs) are increasing the number of components inserted on the surface. This has led the electronics industry to seek improvements in their inspection processes, often making it necessary to increase the level of automation on the production line. The use of machine vision for quality inspection within manufacturing processes has increasingly supported decision making in the approval or rejection of products outside of the established quality standards. This study proposes a hybrid smart-vision inspection system with a machine vision concept and vision sensor equipment to verify 24 components and eight screw threads. The goal of this study is to increase automated inspection reliability and reduce non-conformity rates in the manufacturing process on the assembly line of automotive products using machine vision. The system uses a camera to collect real-time images of the assembly fixtures, which are connected to a CMOS color vision sensor. The method is highly accurate in complex industry environments and exhibits specific feasibility and effectiveness. The results indicate high performance in the failure mode defined during this study, obtaining the best inspection performance through a strategy using Vision Builder for automated inspection. This approach reduced the action priority by improving the failure mode and effect analysis (FMEA) method. Full article
(This article belongs to the Topic Smart Production in Terms of Industry 4.0 and 5.0)
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