Pub Date : 2023-05-09DOI: 10.3389/fmech.2023.1211250
Ehsan Ban, B. Freedman, Lucas R. Smith, R. Wells
Department of Biomedical Engineering, Yale University, New Haven, CT, United States, Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA, United States, Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA, United States, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
{"title":"Editorial: The mechanobiology of collagen remodeling in health and disease","authors":"Ehsan Ban, B. Freedman, Lucas R. Smith, R. Wells","doi":"10.3389/fmech.2023.1211250","DOIUrl":"https://doi.org/10.3389/fmech.2023.1211250","url":null,"abstract":"Department of Biomedical Engineering, Yale University, New Haven, CT, United States, Department of Orthopaedic Surgery, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA, United States, Department of Neurobiology, Physiology and Behavior, University of California, Davis, CA, United States, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48678399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-05-05DOI: 10.1007/s11465-022-0735-x
Shufei Qiao, Long Quan, Yunxiao Hao, Lei Ge, Lianpeng Xia
{"title":"Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission mechanisms","authors":"Shufei Qiao, Long Quan, Yunxiao Hao, Lei Ge, Lianpeng Xia","doi":"10.1007/s11465-022-0735-x","DOIUrl":"https://doi.org/10.1007/s11465-022-0735-x","url":null,"abstract":"","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":"1-16"},"PeriodicalIF":4.5,"publicationDate":"2023-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46872388","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-26DOI: 10.3389/fmech.2023.1123751
Xin Lin, Bing Liu, Anchao Shen, Zhiwei Cui, K. Zhu
In situ monitoring during the selective laser melting (SLM) process is a promising solution to mitigate defects and improve the quality of as-built parts. However, the existing monitoring platform lacks collaborative control of the process monitoring components, and as a result, it cannot realize a real-time and accurate signal acquisition at a close distance and multiple angles during the whole printing process. In this paper, driven by multiple motors, an off-axis monitoring platform is constructed that enables movement in conjunction with the scraper and laser beam. A fuzzy control-based velocity optimization is proposed to avoid the shock effect on the imaging quality of the CMOS camera and the collision of the scraper and laser. The error between the current location and target location of the molten pool is utilized as the input of the fuzzy controller. Then, the parameters of the PI controller of the stepping motor are dynamically adjusted. ADAMS and SIMULINK co-simulation are conducted to verify the feasibility of the fuzzy algorithm. Finally, the experiment of collaborative motion and the responses of each module are conducted. The results show that with the proposed collaborative platform, the response speed of the system is improved by about 49.6%, and the initial speed of the motor is decreased by about 12.6%, thus avoiding excessive acceleration of the motor. The response time of each motor is ahead of schedule by about 31.8%, which meets the requirements of motion response for SLM process monitoring.
{"title":"Collaborative control for in situ monitoring of molten pool in selective laser melting","authors":"Xin Lin, Bing Liu, Anchao Shen, Zhiwei Cui, K. Zhu","doi":"10.3389/fmech.2023.1123751","DOIUrl":"https://doi.org/10.3389/fmech.2023.1123751","url":null,"abstract":"In situ monitoring during the selective laser melting (SLM) process is a promising solution to mitigate defects and improve the quality of as-built parts. However, the existing monitoring platform lacks collaborative control of the process monitoring components, and as a result, it cannot realize a real-time and accurate signal acquisition at a close distance and multiple angles during the whole printing process. In this paper, driven by multiple motors, an off-axis monitoring platform is constructed that enables movement in conjunction with the scraper and laser beam. A fuzzy control-based velocity optimization is proposed to avoid the shock effect on the imaging quality of the CMOS camera and the collision of the scraper and laser. The error between the current location and target location of the molten pool is utilized as the input of the fuzzy controller. Then, the parameters of the PI controller of the stepping motor are dynamically adjusted. ADAMS and SIMULINK co-simulation are conducted to verify the feasibility of the fuzzy algorithm. Finally, the experiment of collaborative motion and the responses of each module are conducted. The results show that with the proposed collaborative platform, the response speed of the system is improved by about 49.6%, and the initial speed of the motor is decreased by about 12.6%, thus avoiding excessive acceleration of the motor. The response time of each motor is ahead of schedule by about 31.8%, which meets the requirements of motion response for SLM process monitoring.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47034231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-25DOI: 10.3389/fmech.2023.1086544
M. Parsa, Alexandros Askounis
The drying of solute-laden drops is ubiquitous in everyday life, from paints and printers to the raindrops drying on our windows. Nonetheless, scientific interest has primarily focused on understanding the evaporation kinetics on flat surface, with the key parameter of substrate inclination only recently started being addressed. This work focuses on the influence of moderate substrate inclinations at 20° and 40° on the evaporation kinetics and associated deposit patterns of colloidal drops. Inclination altered the shape of the drops which formed a lower contact angle at the upper side of the drop (rear edge) and larger contact angle at the lower side (front edge). As evaporation rate is a function of contact angle, which in turn is a function of inclination, the evaporation lifetime was extended by 43% and 61% for 20° and 40°, respectively, compared to a flat drop. A theoretical approximation of the evaporative flux across the liquid-vapour interface of the drops showed the contribution of each edge to the evaporation kinetics. These differences in the evaporative fluxes altered the internal flows within the drop and in turn the coffee-ring formation mechanism. The particle deposit shape at the two edges for each drop was visualised which combined with the theoretical arguments allowed the proposition of the particle deposition mechanism in inclined drops: inclination added a gravitationally-driven velocity flow component within the drops, which is perpendicular and hence negligible in flat drops. This additional flow hindered or enhanced the number of particles arriving at the rear and front edges of the inclined drops, respectively, and hence influenced the dimensions of the coffee-ring patterns. Eventually, the particle deposits grew sufficiently tall to effectively stagnate the outward flow which resulted in enhanced particle accumulation at the interior of the drops as inclination increased.
{"title":"Inclined colloidal drops: Evaporation kinetics and pattern formation","authors":"M. Parsa, Alexandros Askounis","doi":"10.3389/fmech.2023.1086544","DOIUrl":"https://doi.org/10.3389/fmech.2023.1086544","url":null,"abstract":"The drying of solute-laden drops is ubiquitous in everyday life, from paints and printers to the raindrops drying on our windows. Nonetheless, scientific interest has primarily focused on understanding the evaporation kinetics on flat surface, with the key parameter of substrate inclination only recently started being addressed. This work focuses on the influence of moderate substrate inclinations at 20° and 40° on the evaporation kinetics and associated deposit patterns of colloidal drops. Inclination altered the shape of the drops which formed a lower contact angle at the upper side of the drop (rear edge) and larger contact angle at the lower side (front edge). As evaporation rate is a function of contact angle, which in turn is a function of inclination, the evaporation lifetime was extended by 43% and 61% for 20° and 40°, respectively, compared to a flat drop. A theoretical approximation of the evaporative flux across the liquid-vapour interface of the drops showed the contribution of each edge to the evaporation kinetics. These differences in the evaporative fluxes altered the internal flows within the drop and in turn the coffee-ring formation mechanism. The particle deposit shape at the two edges for each drop was visualised which combined with the theoretical arguments allowed the proposition of the particle deposition mechanism in inclined drops: inclination added a gravitationally-driven velocity flow component within the drops, which is perpendicular and hence negligible in flat drops. This additional flow hindered or enhanced the number of particles arriving at the rear and front edges of the inclined drops, respectively, and hence influenced the dimensions of the coffee-ring patterns. Eventually, the particle deposits grew sufficiently tall to effectively stagnate the outward flow which resulted in enhanced particle accumulation at the interior of the drops as inclination increased.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":"22 1","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91225571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-19DOI: 10.3389/fmech.2023.1069806
T. Moh, J. Jin, L. A. Wong, M. Tiong, C. Chan
Over the years, the desire to have better thermal comfort in terms of living has been extensively discussed and is in high demand, especially in metropolitan cities. Alongside the desired outcomes, air conditioning facilities have been implemented, but they also bring negative consequences, such as a high energy bill and multi-dimensional environmental impacts. To counter these problems, a hybrid technique combining the evaporative cooling technique with a venturi-shaped natural ventilation tower is proposed. Evaporative cooling takes advantage of cooling in response to the wind blowing through a layer of wetted surface that is built with permeable materials. Combining with the specially designed venturi-shaped natural ventilation tower to improve the volume intake of wind externally, this system is aimed to reduce temperature and achieve thermal comfort by cooling down the air with circulation in a continuous accumulative mode. To gauge the efficiency and effectiveness of this hybrid technique, an evaporative system known as the wind-induced evaporative cooling (WIEC) system is directly fed into a testing chamber (installed with sensors) fabricated with a scale of 1:6. The system was tested in a hot and humid climate with a temperature range of 27°C–34°C. The finding shows that our system is able to reduce temperatures up to 3.873°C with an output cooling capacity of 9 W–476.3 W, which shows the feasibility of this study.
多年来，人们对更好的热舒适生活的渴望得到了广泛的讨论，需求很大，尤其是在大都市。除了预期的结果外，空调设施已经实施，但它们也带来了负面后果，例如高昂的能源账单和多方面的环境影响。为了解决这些问题，提出了一种将蒸发冷却技术与文丘里形自然通风塔相结合的混合技术。蒸发冷却利用了对风吹过一层由可渗透材料制成的湿表面的冷却反应。结合特别设计的文丘里形状的自然通风塔，提高外部的进风量，该系统旨在通过连续累积的循环方式冷却空气，从而降低温度，达到热舒适。为了测量这种混合技术的效率和有效性，一个被称为风致蒸发冷却(WIEC)系统的蒸发系统被直接送入一个1:6比例的测试室(安装有传感器)。该系统在温度范围为27°C - 34°C的湿热气候中进行了测试。研究结果表明，该系统可将温度降低至3.873°C，输出制冷量为9 W - 476.3 W，表明了本研究的可行性。
{"title":"Wind-induced evaporative cooling passive system for tropical hot and humid climate","authors":"T. Moh, J. Jin, L. A. Wong, M. Tiong, C. Chan","doi":"10.3389/fmech.2023.1069806","DOIUrl":"https://doi.org/10.3389/fmech.2023.1069806","url":null,"abstract":"Over the years, the desire to have better thermal comfort in terms of living has been extensively discussed and is in high demand, especially in metropolitan cities. Alongside the desired outcomes, air conditioning facilities have been implemented, but they also bring negative consequences, such as a high energy bill and multi-dimensional environmental impacts. To counter these problems, a hybrid technique combining the evaporative cooling technique with a venturi-shaped natural ventilation tower is proposed. Evaporative cooling takes advantage of cooling in response to the wind blowing through a layer of wetted surface that is built with permeable materials. Combining with the specially designed venturi-shaped natural ventilation tower to improve the volume intake of wind externally, this system is aimed to reduce temperature and achieve thermal comfort by cooling down the air with circulation in a continuous accumulative mode. To gauge the efficiency and effectiveness of this hybrid technique, an evaporative system known as the wind-induced evaporative cooling (WIEC) system is directly fed into a testing chamber (installed with sensors) fabricated with a scale of 1:6. The system was tested in a hot and humid climate with a temperature range of 27°C–34°C. The finding shows that our system is able to reduce temperatures up to 3.873°C with an output cooling capacity of 9 W–476.3 W, which shows the feasibility of this study.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45425111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-17DOI: 10.3389/fmech.2023.1154316
Erik Nordvall, A. Wiberg, M. Tarkian
Introduction: As the increase in electrification poses new demands on power delivery, the quality of the distribution system is paramount. Substations are a critical part of power grids that allow for control and service of the electrical distribution system. Substations are currently developed in a project-based and manually intensive manner, with a high degree of manual work and lengthy lead times. Substations are primarily sold through tenders that are accompanied by an inherent need for engineering-to-order activities. Although necessary, these activities present a paradox as tender processes must be agile and fast. To remedy this shortcoming, this article outlines a knowledge capture and reuse methodology to standardize and automate the product development processes of substation design. Methods: A novel framework for substation design is presented that implements knowledge-based engineering (KBE) and artificial intelligence methods in computer vision to capture knowledge. In addition, a product configuration system is presented, utilizing high-level CAD templates. The development has followed the KBE methodology MOKA. Results: The proposed framework has been implemented on several company cases where three (simplified) are presented in this paper. The framework decreased the time to create a 3D model from a basic electric single line diagram by performing the identification and design tasks in an automated fashion. Discussion: Ultimately, the framework will allow substation design companies to increase competitiveness through automation and knowledge management and enable more tenders to be answered without losing engineering quality.
{"title":"Knowledge-based engineering and computer vision for configuration-based substation design","authors":"Erik Nordvall, A. Wiberg, M. Tarkian","doi":"10.3389/fmech.2023.1154316","DOIUrl":"https://doi.org/10.3389/fmech.2023.1154316","url":null,"abstract":"Introduction: As the increase in electrification poses new demands on power delivery, the quality of the distribution system is paramount. Substations are a critical part of power grids that allow for control and service of the electrical distribution system. Substations are currently developed in a project-based and manually intensive manner, with a high degree of manual work and lengthy lead times. Substations are primarily sold through tenders that are accompanied by an inherent need for engineering-to-order activities. Although necessary, these activities present a paradox as tender processes must be agile and fast. To remedy this shortcoming, this article outlines a knowledge capture and reuse methodology to standardize and automate the product development processes of substation design. Methods: A novel framework for substation design is presented that implements knowledge-based engineering (KBE) and artificial intelligence methods in computer vision to capture knowledge. In addition, a product configuration system is presented, utilizing high-level CAD templates. The development has followed the KBE methodology MOKA. Results: The proposed framework has been implemented on several company cases where three (simplified) are presented in this paper. The framework decreased the time to create a 3D model from a basic electric single line diagram by performing the identification and design tasks in an automated fashion. Discussion: Ultimately, the framework will allow substation design companies to increase competitiveness through automation and knowledge management and enable more tenders to be answered without losing engineering quality.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45728716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-04-06DOI: 10.3389/fmech.2023.1192657
C. Pany, Guoqiang Li
A periodic structure consists of repeating unit cells. Fromman-made multi-span bridges to naturally occurring atomic grids, periodic structures are present everywhere. Brillouin (1953) first used the wave propagationmethod to study the dynamics of periodic lattices. The ability of periodic configurations to create electronic bands in semiconductors and crystals is similar to the structural/acoustic bandgap of elastic media. Reinforced plate and shell structures are frequently used in a variety of structural applications, including bridges, ship hulls, decks, aircraft, and aerospace rocket/missile structures, which are examples of periodic structures. Mead (1996) presents a thorough overview of the available literature on the vibration analysis of periodic structures. In the areas of homogeneous/heterogeneous composite structures, waveguides, phononic crystals (PCs), acoustic/elastic metamaterials, vibration acoustic isolation, noise suppression devices, vibration control, directed energy flow, etc., this might result in great implementations. Periodic structures are also used to study the tunability (Zheng et al., 2019) of filter characteristics, such as required acoustic band gap, propagation, cut-off frequency, attenuation, and response direction. Health monitoring (Groth et al., 2020) and damage detection of these structures requires a good understanding of the propagation of elastic waves through such periodic structures. In particular, the effect of periodicity on the movement of electromagnetic waves (Pierre, 2010) has been extensively studied and they have been applied to many optical and electromagnetic devices (Bostrom, 1983). The finite element (FE) theory-based numerical approach exhibits the most diversity and usefulness in modeling physical structures among the various numerical approaches. The theory of wave propagation in the periodic structure with FEM (PSFEM) is the goal of the study topic, and the numerical solution is based on the FE analysis of the unit cell of the structure. This numerical FE method enables high accuracy with very little computational effort and is a recommended option for predicting waves in one-dimensional and twodimensional single waveguides (Orris and Petyt, 1974; Pany et al., 2002; Pany and Parthan, 2003a; Pany et al., 2003; Pany and Parthan, 2003b; Pany, 2022). The majority of published OPEN ACCESS
周期结构由重复的单元组成。从人造的多跨桥梁到自然发生的原子网格，周期结构无处不在。布里渊(1953)首先用波传播法研究周期格的动力学。周期性结构在半导体和晶体中产生电子带的能力类似于弹性介质的结构/声学带隙。增强板壳结构经常用于各种结构应用，包括桥梁、船体、甲板、飞机和航天火箭/导弹结构，这些都是周期性结构的例子。Mead(1996)对周期结构振动分析的现有文献进行了全面概述。在均匀/非均匀复合结构、波导、声子晶体(PCs)、声学/弹性超材料、振动隔声、噪声抑制装置、振动控制、定向能流等领域，这可能会带来很大的实现。周期结构还用于研究滤波器特性的可调性(Zheng et al.， 2019)，如所需的声带隙、传播、截止频率、衰减和响应方向。这些结构的健康监测(growth et al.， 2020)和损伤检测需要很好地理解弹性波在这些周期性结构中的传播。特别是，周期性对电磁波运动的影响(Pierre, 2010)已被广泛研究，并已应用于许多光学和电磁设备(Bostrom, 1983)。在各种数值方法中，基于有限元理论的数值方法在模拟物理结构方面表现出最大的多样性和实用性。本文的研究目标是利用有限元法(PSFEM)研究周期结构中的波传播理论，其数值解是基于结构单元格的有限元分析。这种数值有限元方法能够以很少的计算工作量实现高精度，是预测一维和二维单波导中的波的推荐选择(Orris和Petyt, 1974;Pany et al.， 2002;Pany and Parthan, 2003;Pany等人，2003;company and Parthan, 2003;公司,2022年)。大部分出版的都是OPEN ACCESS
{"title":"Editorial: Application of periodic structure theory with finite element approach","authors":"C. Pany, Guoqiang Li","doi":"10.3389/fmech.2023.1192657","DOIUrl":"https://doi.org/10.3389/fmech.2023.1192657","url":null,"abstract":"A periodic structure consists of repeating unit cells. Fromman-made multi-span bridges to naturally occurring atomic grids, periodic structures are present everywhere. Brillouin (1953) first used the wave propagationmethod to study the dynamics of periodic lattices. The ability of periodic configurations to create electronic bands in semiconductors and crystals is similar to the structural/acoustic bandgap of elastic media. Reinforced plate and shell structures are frequently used in a variety of structural applications, including bridges, ship hulls, decks, aircraft, and aerospace rocket/missile structures, which are examples of periodic structures. Mead (1996) presents a thorough overview of the available literature on the vibration analysis of periodic structures. In the areas of homogeneous/heterogeneous composite structures, waveguides, phononic crystals (PCs), acoustic/elastic metamaterials, vibration acoustic isolation, noise suppression devices, vibration control, directed energy flow, etc., this might result in great implementations. Periodic structures are also used to study the tunability (Zheng et al., 2019) of filter characteristics, such as required acoustic band gap, propagation, cut-off frequency, attenuation, and response direction. Health monitoring (Groth et al., 2020) and damage detection of these structures requires a good understanding of the propagation of elastic waves through such periodic structures. In particular, the effect of periodicity on the movement of electromagnetic waves (Pierre, 2010) has been extensively studied and they have been applied to many optical and electromagnetic devices (Bostrom, 1983). The finite element (FE) theory-based numerical approach exhibits the most diversity and usefulness in modeling physical structures among the various numerical approaches. The theory of wave propagation in the periodic structure with FEM (PSFEM) is the goal of the study topic, and the numerical solution is based on the FE analysis of the unit cell of the structure. This numerical FE method enables high accuracy with very little computational effort and is a recommended option for predicting waves in one-dimensional and twodimensional single waveguides (Orris and Petyt, 1974; Pany et al., 2002; Pany and Parthan, 2003a; Pany et al., 2003; Pany and Parthan, 2003b; Pany, 2022). The majority of published OPEN ACCESS","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44803148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-30DOI: 10.3389/fmech.2023.1142421
Yifeng Gong, Ge Sun, Aditya Nair, Aditya Bidwai, C. Raghuram, John Grezmak, Guillaume Sartoretti, K. Daltorio
Legged robots can have a unique role in manipulating objects in dynamic, human-centric, or otherwise inaccessible environments. Although most legged robotics research to date typically focuses on traversing these challenging environments, many legged platform demonstrations have also included “moving an object” as a way of doing tangible work. Legged robots can be designed to manipulate a particular type of object (e.g., a cardboard box, a soccer ball, or a larger piece of furniture), by themselves or collaboratively. The objective of this review is to collect and learn from these examples, to both organize the work done so far in the community and highlight interesting open avenues for future work. This review categorizes existing works into four main manipulation methods: object interactions without grasping, manipulation with walking legs, dedicated non-locomotive arms, and legged teams. Each method has different design and autonomy features, which are illustrated by available examples in the literature. Based on a few simplifying assumptions, we further provide quantitative comparisons for the range of possible relative sizes of the manipulated object with respect to the robot. Taken together, these examples suggest new directions for research in legged robot manipulation, such as multifunctional limbs, terrain modeling, or learning-based control, to support a number of new deployments in challenging indoor/outdoor scenarios in warehouses/construction sites, preserved natural areas, and especially for home robotics.
{"title":"Legged robots for object manipulation: A review","authors":"Yifeng Gong, Ge Sun, Aditya Nair, Aditya Bidwai, C. Raghuram, John Grezmak, Guillaume Sartoretti, K. Daltorio","doi":"10.3389/fmech.2023.1142421","DOIUrl":"https://doi.org/10.3389/fmech.2023.1142421","url":null,"abstract":"Legged robots can have a unique role in manipulating objects in dynamic, human-centric, or otherwise inaccessible environments. Although most legged robotics research to date typically focuses on traversing these challenging environments, many legged platform demonstrations have also included “moving an object” as a way of doing tangible work. Legged robots can be designed to manipulate a particular type of object (e.g., a cardboard box, a soccer ball, or a larger piece of furniture), by themselves or collaboratively. The objective of this review is to collect and learn from these examples, to both organize the work done so far in the community and highlight interesting open avenues for future work. This review categorizes existing works into four main manipulation methods: object interactions without grasping, manipulation with walking legs, dedicated non-locomotive arms, and legged teams. Each method has different design and autonomy features, which are illustrated by available examples in the literature. Based on a few simplifying assumptions, we further provide quantitative comparisons for the range of possible relative sizes of the manipulated object with respect to the robot. Taken together, these examples suggest new directions for research in legged robot manipulation, such as multifunctional limbs, terrain modeling, or learning-based control, to support a number of new deployments in challenging indoor/outdoor scenarios in warehouses/construction sites, preserved natural areas, and especially for home robotics.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42681346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-27DOI: 10.3389/fmech.2023.1128447
Stefan Hofmann, T. Lohner, K. Stahl
Lubricants with a functional water portion have demonstrated a drastic reduction in friction under elastohydrodynamic lubrication conditions. With water-containing polyalkylene glycols, superlubricity with coefficients of friction <0.01 have been measured in model and gear contacts. In addition to the low friction, their calorimetric properties make them particularly interesting for application in electrified vehicles because the liquid can simultaneously serve as lubricant for the gearbox and coolant for the electric motors and the power electronics. In this study, the influence of water content between 8 wt% and 40 wt% of water-soluble polyalkylene glycols on friction and film thickness in elastohydrodynamically lubricated rolling-sliding contacts such as in gears and bearings is investigated. A polyalphaolefine oil is used as a reference. Friction has been measured on a ball-on-disk tribometer and film thickness on an optical tribometer. For a water content of 40 wt%, superlubricity with coefficients of friction down to 0.004 are found. The decrease in friction is up to 95% compared to the polyalphaolefine reference. The measured film thickness decreases with increasing water content. For a water content of 8 wt%, the film thickness is similar to that of the polyalphaolefine reference while at the same time friction is still reduced by 81%. Depending on the friction and film thickness requirements of a specific tribosystem, the water content of a water-containing polyalkylene glycol can be chosen accordingly.
{"title":"Influence of water content on elastohydrodynamic friction and film thickness of water-containing polyalkylene glycols","authors":"Stefan Hofmann, T. Lohner, K. Stahl","doi":"10.3389/fmech.2023.1128447","DOIUrl":"https://doi.org/10.3389/fmech.2023.1128447","url":null,"abstract":"Lubricants with a functional water portion have demonstrated a drastic reduction in friction under elastohydrodynamic lubrication conditions. With water-containing polyalkylene glycols, superlubricity with coefficients of friction <0.01 have been measured in model and gear contacts. In addition to the low friction, their calorimetric properties make them particularly interesting for application in electrified vehicles because the liquid can simultaneously serve as lubricant for the gearbox and coolant for the electric motors and the power electronics. In this study, the influence of water content between 8 wt% and 40 wt% of water-soluble polyalkylene glycols on friction and film thickness in elastohydrodynamically lubricated rolling-sliding contacts such as in gears and bearings is investigated. A polyalphaolefine oil is used as a reference. Friction has been measured on a ball-on-disk tribometer and film thickness on an optical tribometer. For a water content of 40 wt%, superlubricity with coefficients of friction down to 0.004 are found. The decrease in friction is up to 95% compared to the polyalphaolefine reference. The measured film thickness decreases with increasing water content. For a water content of 8 wt%, the film thickness is similar to that of the polyalphaolefine reference while at the same time friction is still reduced by 81%. Depending on the friction and film thickness requirements of a specific tribosystem, the water content of a water-containing polyalkylene glycol can be chosen accordingly.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42297964","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-03-27DOI: 10.3389/fmech.2023.1108180
Oliver Maas
Planned offshore wind farm clusters have a rated capacity of more than 10 GW. The layout optimization and yield estimation of wind farms is often performed with computationally inexpensive, analytical wake models. As recent research results show, the flow physics in large (multi-gigawatt) offshore wind farms are more complex than in small (sub-gigawatt) wind farms. Since analytical wake models are tuned with data of existing, sub-gigawatt wind farms they might not produce accurate results for large wind farm clusters. In this study the results of a large-eddy simulation of a 15 GW wind farm are compared with two analytical wake models to demonstrate potential discrepancies. The TurbOPark model and the Niayifar and Porté-Agel model are chosen because they use a Gaussian wake profile and a turbulence model. The wind farm has a finite size in the crosswise direction, unlike as in many other large-eddy simulation wind farm studies, in which the wind farm is effectively infinitely wide due to the cyclic boundary conditions. The results show that new effects like crosswise divergence and convergence occur in such a finite-size multi-gigawatt wind farm. The comparison with the wake models shows that there are large discrepancies of up to 40% between the predicted wind farm power output of the wake models and the large-eddy simulation. An energy budget analysis is made to explain the discrepancies. It shows that the wake models neglect relevant kinetic energy sources and sinks like the geostrophic forcing, the energy input by pressure gradients and energy dissipation. Taking some of these sources and sinks into account could improve the accuracy of the wake models.
{"title":"Large-eddy simulation of a 15 GW wind farm: Flow effects, energy budgets and comparison with wake models","authors":"Oliver Maas","doi":"10.3389/fmech.2023.1108180","DOIUrl":"https://doi.org/10.3389/fmech.2023.1108180","url":null,"abstract":"Planned offshore wind farm clusters have a rated capacity of more than 10 GW. The layout optimization and yield estimation of wind farms is often performed with computationally inexpensive, analytical wake models. As recent research results show, the flow physics in large (multi-gigawatt) offshore wind farms are more complex than in small (sub-gigawatt) wind farms. Since analytical wake models are tuned with data of existing, sub-gigawatt wind farms they might not produce accurate results for large wind farm clusters. In this study the results of a large-eddy simulation of a 15 GW wind farm are compared with two analytical wake models to demonstrate potential discrepancies. The TurbOPark model and the Niayifar and Porté-Agel model are chosen because they use a Gaussian wake profile and a turbulence model. The wind farm has a finite size in the crosswise direction, unlike as in many other large-eddy simulation wind farm studies, in which the wind farm is effectively infinitely wide due to the cyclic boundary conditions. The results show that new effects like crosswise divergence and convergence occur in such a finite-size multi-gigawatt wind farm. The comparison with the wake models shows that there are large discrepancies of up to 40% between the predicted wind farm power output of the wake models and the large-eddy simulation. An energy budget analysis is made to explain the discrepancies. It shows that the wake models neglect relevant kinetic energy sources and sinks like the geostrophic forcing, the energy input by pressure gradients and energy dissipation. Taking some of these sources and sinks into account could improve the accuracy of the wake models.","PeriodicalId":48635,"journal":{"name":"Frontiers of Mechanical Engineering","volume":" ","pages":""},"PeriodicalIF":4.5,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43832768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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