Machines Pub Date : 2025-12-10 DOI: 10.3390/machines13121133

Yoshiki Tsunekawa, Kosuke Sekiyama

引用次数: 1

Physics-Based Self-Supervised Grasp Pose Detection 基于物理的自监督抓取姿态检测

Machines Pub Date : 2024-12-28 DOI: 10.3390/machines13010012

Jon Ander Ruiz, Ander Iriondo, Elena Lazkano, Ander Ansuategi, Iñaki Maurtua

{"title":"Physics-Based Self-Supervised Grasp Pose Detection","authors":"Jon Ander Ruiz, Ander Iriondo, Elena Lazkano, Ander Ansuategi, Iñaki Maurtua","doi":"10.3390/machines13010012","DOIUrl":"https://doi.org/10.3390/machines13010012","url":null,"abstract":"Current industrial robotic manipulators have made their lack of flexibility evident. The systems must know beforehand the piece and its position. To address this issue, contemporary approaches typically employ learning-based techniques, which rely on extensive amounts of data. To obtain vast data, an often sought tool is an extensive grasp dataset. This work introduces our Physics-Based Self-Supervised Grasp Pose Detection (PBSS-GPD) pipeline for model-based grasping point detection, which is useful for generating grasp pose datasets. Given a gripper-object pair, it samples grasping pose candidates using a modified version of GPD (implementing inner-grasps, CAD support…) and quantifies their quality using the MuJoCo physics engine and a grasp quality metric that takes into account the pose of the object over time. The system is optimized to run on CPU in headless-parallelized mode, with the option of running in a graphical interface or headless and storing videos of the process. The system has been validated obtaining grasping poses for a subset of Egad! objects using the Franka Panda two-finger gripper, compared with state-of-the-art grasp generation pipelines and tested in a real scenario. While our system achieves similar accuracy compared to a contemporary approach, 84% on the real-world validation, it has proven to be effective at generating grasps with good centering 18 times faster than the compared system.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"13 1","pages":"12-12"},"PeriodicalIF":0.0,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2075-1702/13/1/12/pdf?version=1735374888","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147899370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach 海洋环境中PDA纳米颗粒诱导的润滑膜形成：一种主动方法

Machines Pub Date : 2024-11-16 DOI: 10.3390/machines12110817

Xinqi Zou, Zhenghao Ge, Chaobao Wang, Yuyang Xi

{"title":"PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach","authors":"Xinqi Zou, Zhenghao Ge, Chaobao Wang, Yuyang Xi","doi":"10.3390/machines12110817","DOIUrl":"https://doi.org/10.3390/machines12110817","url":null,"abstract":"The low viscosity of water-lubricated films compromises their load-bearing capacity, posing challenges for practical application. Enhancing the lubrication stability of these films under load is critical for the successful use of seawater-lubricated bearings in engineering. Polydopamine (PDA) shows great potential to address this issue due to its strong bio-inspired adhesion and hydration lubrication properties. Thus, PDA nanoparticles and seawater suspensions were synthesized to promote adhesive lubricating film formation under dynamic friction. The lubrication properties of PDA suspensions were evaluated on Cu ball and ultra-high molecular weight polyethylene (UHMWPE) tribo-pairs, with a detailed comparison to seawater. The results show PDA nanoparticles provide excellent adhesion and lubrication, enhancing the formation of lubricating films during friction with seawater. Under identical conditions, PDA suspensions demonstrated the lowest friction coefficient and minimal wear. At 3 N, friction decreased by 56% and wear by 47% compared to distilled water. These findings suggest a novel strategy for using PDA as a lubricant in seawater for engineering applications.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"12 11","pages":"817-817"},"PeriodicalIF":0.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.mdpi.com/2075-1702/12/11/817/pdf?version=1731724417","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147917085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Determination of Energy Losses of the Crank Press Mechanism 曲柄压力机机构能量损失的测定

Machines Pub Date : 2024-07-15 DOI: 10.3390/machines12070477

Jan Hlavac, Jiri Dekastello

引用次数: 0

A Study on Micro-Pit Texture Parameter Optimization and Its Tribological Properties 微坑纹理参数优化及其摩擦学特性研究

Machines Pub Date : 2024-07-15 DOI: 10.3390/machines12070475

Yazhou Mao, Yuxuan Zhang, Jingyang Zheng, Lilin Li, Yuchun Huang, Shaolin Shi, Linyuan Wang, Jiaming Pei, Zichen Li

{"title":"A Study on Micro-Pit Texture Parameter Optimization and Its Tribological Properties","authors":"Yazhou Mao, Yuxuan Zhang, Jingyang Zheng, Lilin Li, Yuchun Huang, Shaolin Shi, Linyuan Wang, Jiaming Pei, Zichen Li","doi":"10.3390/machines12070475","DOIUrl":"https://doi.org/10.3390/machines12070475","url":null,"abstract":"In this paper, the effect of micro-dimple textures (produced by a laser) on the tribological properties of bearings is investigated. This study offers guidelines to reduce the friction torque of the bearing pair and addresses the problem of difficult start-ups after shutdowns. Micro-pits with different texture diameters and depths were machined on the surface of journal bearings. Then, the impact of several different texture parameters on the tribological performance of the bearing pairs was studied using an orthogonal experimental design. Subsequently, the surface morphology of the bearings before and after the friction and wear test was observed using scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS). These observations were then used to determine the type/state of friction and wear, which also improves our understanding of how texture affects the service life of bearings. The results indicate that the bearings’ micro-pit surface hardness follows an approximate parabolic spatial distribution that decreases along the micro-pit wall. Furthermore, the laser processing of surface textures was found to cause hardening in certain areas, and the chemical composition of elemental carbon and oxygen at the inner surface of processed bearings increased by 31.1% and 7.9%, respectively. Moreover, abrasive wear was identified as the primary form of wear. The textured surface’s antifriction mechanism primarily functioned to trap particles, which acted as a secondary lubrication source and altered the lubrication states by serving as a medium for supplied lubricants. The results confirm that a suitable selection of texture parameters can not only effectively reduce the friction coefficient without shortening the service life of the bearing pair but also facilitate the smooth start-up of the rotor–bearing system.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"43 33","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141645240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Brush Seal Performance with Ideal Gas Working Fluid under Static Rotor Condition 静态转子条件下使用理想气体工作流体的电刷密封性能

Machines Pub Date : 2024-07-15 DOI: 10.3390/machines12070476

Altyib Abdallah Mahmoud Ahmed, Meihong Liu, Yuchi Kang, Juan Wang, Aboubaker I. B. Idriss, Nguyen Thi Trung Tin

引用次数: 0

The State of Health of Electrical Connectors 电气连接器的健康状况

Machines Pub Date : 2024-07-14 DOI: 10.3390/machines12070474

Jian Song, Abhay Shukla, Roman Probst

{"title":"The State of Health of Electrical Connectors","authors":"Jian Song, Abhay Shukla, Roman Probst","doi":"10.3390/machines12070474","DOIUrl":"https://doi.org/10.3390/machines12070474","url":null,"abstract":"For modern machines, factories and electric and autonomous vehicles, the importance of vreliable electrical connectors cannot be overstated. With an increasing number of connectors being used in machines, factories and vehicles, ensuring their reliability is crucial for comfort and safety alike. One of the key indicators of reliability is the lifetime of connectors. To evaluate the lifetime of electrical connectors, a testing method and a model for calculating their lifetime based on the test data were developed. The results from these tests were compared to failure analysis data from long-term field operations. The findings indicate that the laboratory tests can accurately reproduce the main failures observed in the field. However, such lifetime tests can be time- and labor-intensive. To address this challenge, a data-driven method is proposed that predicts the lifetime of electrical connectors using statistical analysis of electrical contact resistance data collected from short-term tests. The predictions from this method were compared to actual results obtained from long-term tests. A strong correlation was observed between the contact resistance development in short-term tests and the number of failures in later stages of testing. Thus, apart from predicting the lifetime of connectors, this method can also be applied for failure prognosis in real-time operations.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"51 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141650056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Impact of Installation Deviations on the Dynamic Characteristics of the Shaft System for 1 Gigawatt Hydro-Generator Unit 安装偏差对 1 千兆瓦水轮发电机组轴系动态特性的影响

Machines Pub Date : 2024-07-12 DOI: 10.3390/machines12070473

Gangyun Song, Xingxing Huang, Haijun Li, Zhengwei Wang, Dong Wang

{"title":"Impact of Installation Deviations on the Dynamic Characteristics of the Shaft System for 1 Gigawatt Hydro-Generator Unit","authors":"Gangyun Song, Xingxing Huang, Haijun Li, Zhengwei Wang, Dong Wang","doi":"10.3390/machines12070473","DOIUrl":"https://doi.org/10.3390/machines12070473","url":null,"abstract":"The shaft system, transferring the kinetic energy of water flow into electrical energy, is the most critical component in hydropower plants. Installation deviations of the shaft system for a giant hydro-generator unit can have significant impacts on its dynamic characteristics and overall performance. In this investigation, a three-dimensional geometry of the shaft system of an operating hydro-generator unit prototype with a rated power of 1 GW is established. Then, the calculation model of the shaft system is generated accordingly with tetrahedral and hexahedral elements. By applying different boundary conditions, the finite-element method is used to analyze the influences of installation deviations, including shaft radial misalignment and angular misalignment, on the dynamic characteristics of the shaft system. The calculation results reveal that the installation deviations change the natural frequencies, critical speeds, and mode shapes of the shaft system to a certain degree. The natural frequencies of the backward precession motion with installation deviations are reduced by 23% and 38% for the rated speed and the maximum runaway speed. Furthermore, for the forward precession motion, they increased by 30% and 48%, respectively. The critical speeds for the shaft system with radial and angular deviations are 3.2% and 3% larger than the critical speed of the shaft system without any mounting deviations. The radial and angular installation deviations below the maximum permissible values will not result in the structural performance degradation of the 1 GW hydro-generator shaft system. The conclusion drawn in this research can be used as a valuable reference for installing other rotating machinery.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"58 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141654196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Material Extrusion 3D Printing of Micro-Porous Copper-Based Structure for Water Filters 材料挤压三维打印用于净水器的微孔铜基结构

Machines Pub Date : 2024-07-12 DOI: 10.3390/machines12070470

Nikola Kotorčević, S. Milenković, F. Živić, Branka Jordović, Dragan Adamović, Petar Todorović, N. Grujovic

引用次数: 0

Reinforcement Learning-Based Auto-Optimized Parallel Prediction for Air Conditioning Energy Consumption 基于强化学习的空调能耗自动优化并行预测

Machines Pub Date : 2024-07-12 DOI: 10.3390/machines12070471

Chao Gu, Shentao Yao, Yifan Miao, Ye Tian, Yuru Liu, Zhicheng Bao, Tao Wang, Baoyu Zhang, Tao Chen, Weishan Zhang

{"title":"Reinforcement Learning-Based Auto-Optimized Parallel Prediction for Air Conditioning Energy Consumption","authors":"Chao Gu, Shentao Yao, Yifan Miao, Ye Tian, Yuru Liu, Zhicheng Bao, Tao Wang, Baoyu Zhang, Tao Chen, Weishan Zhang","doi":"10.3390/machines12070471","DOIUrl":"https://doi.org/10.3390/machines12070471","url":null,"abstract":"Air conditioning contributes a high percentage of energy consumption over the world. The efficient prediction of energy consumption can help to reduce energy consumption. Traditionally, multidimensional air conditioning energy consumption data could only be processed sequentially for each dimension, thus resulting in inefficient feature extraction. Furthermore, due to reasons such as implicit correlations between hyperparameters, automatic hyperparameter optimization (HPO) approaches can not be easily achieved. In this paper, we propose an auto-optimization parallel energy consumption prediction approach based on reinforcement learning. It can parallel process multidimensional time series data and achieve the automatic optimization of model hyperparameters, thus yielding an accurate prediction of air conditioning energy consumption. Extensive experiments on real air conditioning datasets from five factories have demonstrated that the proposed approach outperforms existing prediction solutions, with an increase in average accuracy by 11.48% and an average performance improvement of 32.48%.","PeriodicalId":509264,"journal":{"name":"Machines","volume":"48 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141653188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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