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SSRN 2022年

作者： Li, Jingchang Cao, Longchao Liu, Huaping Zhou, Qi Zhang, Xiangdong Li, Menglei School of Aerospace Engineering Huazhong University of Science & Technology Wuhan430074 China School of Mechanical Engineering & Automation Wuhan Textile University Wuhan430200 China Wuhan Second Ship Design and Research Institute Wuhan430064 China

As one of the popular metal additive manufacturing (AM) techniques, laser powder bed fusion (LPBF) can produce near net shape products with complex geometries. Unfortunately, the LPBF technology still largely suffer from poor part consistency and process repeatability. This has driven significant research efforts combining process sensing and data-driven models to perform in-situ monitoring for ensuring part quality. However, the collected sensing datasets in actual applications may be imbalanced and making it challenging for in-situ monitoring. In this paper, we propose an imbalanced data generation and fusion approach to achieve in-situ quality monitoring with imbalanced datasets in the LPBF process. Three imbalanced datasets of layer-wise images, acoustic emission (AE) signals, and photodiode signals are first collected and created by the developed multi-sensor in-situ monitoring system. Then, a Generative Adversarial Network (GAN)-based data generation model is proposed to generate high-quality samples of the minority classes. Finally, a deep learning (DL)-based multi-sensor fusion method is established to fuse the three augmented balanced datasets. Results show that the generated high-quality samples can significantly improve the model performance, and the proposed DL-based multi-sensor fusion model outperforms the single-sensor-based quality classification models, providing a possible way for imbalanced quality monitoring in the LPBF process. © 2022, The Authors. All rights reserved.

关键词： 3D printers

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A Novel Construction Method for 1-Dof Multi-Loop Kirigami Mechanisms

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SSRN 2024年

作者： Lv, Weilin Nie, Wansui Wei, Jun Zhang, Jianjun Meng, Chuizhou Liu, Teng Sui, Jin Guo, Shijie Engineering Research Center The Ministry of Education for Intelligent Rehabilitation Equipment and Detection Technologies Hebei University of Technology Tianjin300401 China Hebei Provincial Key Laboratory of Robot Perception and Human-Machine Fusion Hebei University of Technology Tianjin300401 China School of Mechanical Engineering Hebei University of Technology Tianjin300401 China State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China Institutes for Robotics and Intelligent Manufacturing Chinese Academy of Sciences Shenyang110169 China

Kirigami has been utilized in designing deployable mechanisms for various engineering applications. This paper presents a novel construction method for one-degree-of-freedom (1-DOF) multi-loop kirigami mechanisms whose folding motions are kinematically equivalent to their original degree-4 rigid origami. Firstly, we introduce a family of single-loop kirigami (SLK) as the main loop of 1-DOF multi-loop kirigami. Secondly, the coupling-constraint properties of multi-DOF SLKs are clarified, and the structural characteristics of the 1-DOF multi-loop kirigami are defined, based on which, the construction method for the 1-DOF multi-loop kirigami is proposed. Thirdly, the representative models are selected and their kinematics are presented to demonstrate their capability to achieve folding motion equivalent to their origami prototypes, thus verifying the validity of our proposed methodology. Fourthly, the non-constraint condition of the 1-DOF multi-loop kirigami is presented. Finally, we propose extended configurations of 1-DOF multi-loop kirigami and provide the forward and inverse design methods for constructing kirigami meshes. The proposed methodology facilitates the design of large-scale deployable structures. © 2024, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

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Actuation manifold from snapshot data

arXiv

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arXiv 2024年

作者： Marra, Luigi Cornejo Maceda, Guy Y. Meilán-Vila, Andrea Guerrero, Vanesa Rashwan, Salma Noack, Bernd R. Discetti, Stefano Ianiro, Andrea Department of Aerospace Engineering Universidad Carlos III de Madrid Av. de la Universidad 30 Leganés Madrid28911 Spain Chair of Artificial Intelligence and Aerodynamics School of Mechanical Engineering and Automation Harbin Institute of Technology Shenzhen518055 China Department of Statistics Universidad Carlos III de Madrid Calle Madrid 126 Getafe Madrid28903 Spain Guangdong Provincial Key Laboratory of Intelligent Morphing Mechanisms and Adaptive Robotics Harbin Institute of Technology Shenzhen518055 China

We propose a data-driven methodology to learn a low-dimensional manifold of controlled flows. The starting point is resolving snapshot flow data for a representative ensemble of actuations. Key enablers for the actuation manifold are isometric mapping as encoder, and a combination of a neural network and a k-nearest-neighbour interpolation as decoder. This methodology is tested for the fluidic pinball, a cluster of three parallel cylinders perpendicular to the oncoming uniform flow. The centres of these cylinders are the vertices of an equilateral triangle pointing upstream. The flow is manipulated by constant rotation of the cylinders, i.e. described by three actuation parameters. The Reynolds number based on a cylinder diameter is chosen to be 30. The unforced flow yields statistically symmetric periodic shedding represented by a one-dimensional limit cycle. The proposed methodology yields a five-dimensional manifold describing a wide range of dynamics with small representation error. Interestingly, the manifold coordinates automatically unveil physically meaningful parameters. Two of them describe the downstream periodic vortex shedding. The other three describe the near-field actuation, i.e. the strength of boat-tailing, the Magnus effect and forward stagnation point. The manifold is shown to be a key enabler for control-oriented flow estimation. © 2024, CC BY-NC-ND.

关键词： Reynolds number

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A model for universal spatial variations of temperature fluctuations inturbulent Rayleigh-Bénard convection

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Theoretical & Applied Mechanics Letters 2021年第2期11卷 102-104页

作者： Xiaozhou He Eberhard Bodenschatz Guenter Ahlers School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen 518055China Max Planck Institute for Dynamics and Self Organization D-37073 GöttingenGermany International Collaboration for Turbulence Research Institute for Nonlinear Dynamics University of GöttingenD-37073 GöttingenGermany Laboratory of Atomic and Solid-State Physics and Sibley School of Mechanical and Aerospace Engineering Cornell UniversityIthacaNY 14853USA Department of Physics University of CaliforniaSanta BarbaraCA 93106USA

We propose a theoretical model for spatial variations of the temperature varianceσ2(z,r)(z is the dis-tance from the sample bottom and r the radial coordinate)in turbulent Rayleigh-Bénard convection(RBC).Adapting the“attached-eddy”modelofshearflowtothe plumesofRBC,wederivedanequationforσ2 which is based on the universal scaling of the normalized RBC temperature *** equation in-cludes both logarithmic and power-law dependences on z/λth,whereλth is the thermal boundary layer *** equation parameters depend on r and the Prandtl number Pr,but have only an extremelyweak dependence on the Rayleigh number Ra Thus our model provides a near-universal equation for thetemperature variance profile in turbulent RBC.

关键词： Rayleigh-Bénard convection Temperature variance profile Attached-eddy Law of wall

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Evolution-based Deployment with Efficient Routing and Crow Search Optimization in Internet of Things Application

Evolution-based Deployment with Efficient Routing and Crow S...

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International Conference on ent Computing and Control Systems (ICICCS)

作者： C. Kalaivanan Ayman Amer Maria Rubiston. M M. Vennila Jayant Giri M. Dinesh Department of EEE Sona College of Technology Salem Department of Energy Engineer Zarqa University Zarqa Jordan College of Engineering University of Business and Technology Jeddah Saudi Arabia Department of ECE S.A. Engineering College Chennai Department of of Robotics and Automation Karpaga Vinayaga College of Engineering and Technology Department of Mechanical Engineering Yeshwantrao Chavan College of Engineering Nagpur Division of Research and Development Lovely Professional University Phagwara India Department of VLSI Microelectronics Saveetha School of Engineering Saveetha Institute of Medical and Technical Sciences (SIMATS) Chennai

ISBN: (数字)9798331512088

ISBN: (纸本)9798331512095

IoT technologies to bolster residential security, safety, and sustainability. By leveraging facial recognition for door access, enhancing fire safety monitoring, and integrating energy harvesting, it aims to create more resilient and eco-friendly residential environments. These innovations offer comprehensive solutions to address evolving challenges and optimize residential living. An ED Model coupled with Crow Search Optimization (CSO) for enhancing the efficiency and reliability of IoT applications. The ED model integrates static routing mechanisms with efficient protocols like AOMDV, ensuring robust connectivity and energy-efficient operation in diverse environments. Leveraging CSO, inspired by collective crow intelligence, enhances network performance by dynamically adapting to changing conditions. Through simulations and comprehensive analysis, the proposed approach demonstrates superior performance compared to existing models, achieving high data delivery ratio, network throughput, and energy efficiency. This integrated framework offers a sustainable solution for resilient IoT deployments, addressing evolving challenges and optimizing residential living environments.

关键词： Adaptation models Analytical models Routing Throughput Energy efficiency Data models Internet of Things Reliability Sustainable development Optimization

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Heuristic Online Path Planning for Mobile Air Purification and Disinfection Robot In Regulating Indoor Air Quality

Heuristic Online Path Planning for Mobile Air Purification a...

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IEEE International Conference on robotics and Biomimetics

作者： Qingnan Zhong Kai Chen Jianghua Duan Jun Ma Robotics and Human Machine Interface Laboratory HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute Futian China Robotics and Autonomous Systems Thrust The Hong Kong University of Science and Technology (Guangzhou) Guangzhou China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology China HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute Futian China Division of Emerging Interdisciplinary Areas The Hong Kong University of Science and Technology China

In light of past epidemics, people have become more aware of the possibility of viruses on object surfaces and in the air. As a result, there is an increasing demand for robots capable of autonomously disinfecting surfaces and purifying the air. This paper focuses on a mobile robot equipped with air purification and UV-C LED disinfection to combat airborne pathogens and environmental pollution. Through the onboard sensors, the proposed algorithm uses gaussian process model to predict the high potential air pollution area in real-time without the requirement of a distributed array of sensors, and it avoids environmental modifications. Then we propose the hybrid artificial potential field (HAPF) by integrating the predicted result with the artificial potential field method, to generate a heuristic path that can navigate the robot to the affected areas with obstacle avoidance. Experimental testing in simulated and real-world environments demonstrates the effectiveness of the proposed approach in rapidly planning purification paths, marking significant progress in automated air purification, and disinfection technology.

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Multi-sensor-based Target Pose Estimation for Autonomous Precision Perching of Nano Aerial Vehicles

Multi-sensor-based Target Pose Estimation for Autonomous Pre...

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International Conference on Control, automation and Systems ( ICCAS)

作者： Truong-Dong Do Nguyen Xuan-Mung Ngoc-Phi Nguyen Ji-Won Lee Yong-Seok Lee Seok-Tae Lee Sung-Kyung Hong Department of Convergence Engineering for Intelligent Drone Sejong University Seoul South Korea Faculty of Mechanical and Aerospace Engineering Sejong University Seoul South Korea Human-Robot Interaction Research Center Korea Institute of Robotics and Technology Convergence Pohang South Korea Department of Aerospace Engineering Sejong University Seoul South Korea

Nano Aerial Vehicles have become widely used for a variety of complex missions due to their mobility and the ability to access hard-to-reach areas. In most cases, these tasks require the vehicles to land on ground targets or perch on platforms mounted on diverse surfaces. Considering the surface the vehicle will reach, controlling perching is obviously a challenging task. Besides, the reliability of target position and direction estimation has a significant impact on perching performance. In this paper, a multi-sensor-based target pose estimation for autonomous precision perching of nano drones is proposed. First, the perching target, a cube cage containing a small marker inside a larger one, is designed to enhance pose estimation capability at a wide range of distances. Second, we constructed a nano drone with an upward monocular camera and a 5-direction multi-ranger deck. Next, the flying vehicle’s pose toward the perching target is calculated, followed by a Kalman filter for filtering and estimating the missing data. Finally, we introduced an algorithm to merge the pose data from multiple sensors when drones approach close to the target. Real measurements are conducted on the testbed. The experimental results demonstrated the utility and potential of the adopted approach with millimeter-level precision.

关键词： Location awareness Visualization Pose estimation Merging Land surface Sensors Reliability

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A Modular End Effector with Active Rolling Fingertip for Picking Cloth-Like Objects

A Modular End Effector with Active Rolling Fingertip for Pic...

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IEEE International Conference on automation Science and engineering (CASE)

作者： Kun Zhang Yuanhang Yang Zhiming Chen Hua Chen Michael Yu Wang Wei Zhang Robotics Institute Hong Kong University of Science and Technology Clear Water Bay Hong Kong School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen China HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute Futian Shenzhen China Department of Mechanical & Aerospace Engineering Monash University Clayton Australia

Cloth-like items are ubiquitous in both daily life and industrial production, but their softness makes them difficult to manipulate. This paper focuses on solving the problem of automatic manipulation especially in the scenario of flat surface by introducing a novel end-effector mechanism. The gripper utilizes a modular design concept, enabling it to be reconstructed with a varying number of fingers based on specific requirements. One of the fingers has an active rolling fingertip that rolls up the object from the table to create wrinkles, for easier grasping. Additionally, there are fingertips with revolute joints that enable fine-tuning of the grasp configuration to fix the objects. To test the effectiveness of the mechanism, we manufactured a real gripper device and mounted it on a collaborative robotic arm for grasping tests. Experiments were conducted on six kinds of cloth-like objects with different materials, grasping them from above. The experimental results show that the gripper with this mechanism configuration performs well in this scenario.

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Elastic Wave Propagation in Thick-Walled Hollow Cylinders for Damage Localization Through Inner Surface Sensing

SSRN

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SSRN 2023年

作者： Zhang, Yuanman Shan, Shengbo Cheng, Li Department of Mechanical Engineering The Hong Kong Polytechnic University Kowloon Hong Kong The Hong Kong Polytechnic University Shenzhen Research Institute Shenzhen518057 China Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center The Hong Kong Polytechnic University Kowloon Hong Kong School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai200092 China

Thick-walled hollow cylinders (TWHCs) are widely used in engineering structures and transportation systems, exemplified by train axles. The real-time and online health monitoring of such structures is crucial to ensure their structural integrity and operational safety. While elastic-wave-based structural health monitoring (SHM) shows promise, the development of feasible methods strongly relies on a good understanding and exploitation of the wave propagation properties and their interaction with structural defects. TWHCs usually bear multiple wave modes, which is a less investigated and explored topic as compared with thin- walled structures. This work examines this issue and proposes a dedicated damage localization strategy by using the selected waves captured on the inner surface of a TWHC. It is shown that, alongside the quasi-surface waves on the outer surface, longitudinal waves converted from the thickness-through shear bulk waves are generated to propagate along the inner surface. Their propagation characteristics are exploited for damage localization based on hyperbolic loci methods through inner surface sensing. Numerical studies are conducted to validate the method and assess different transducer configurations, alongside experimental verifications on a benchmark TWHC containing a notch-type defect. Studies provide guidance on damage detection in TWHCs and sensor network design. © 2023, The Authors. All rights reserved.

关键词： Surface waves

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Development of a smart glove for affordable diagnosis of stroke-driven upper extremity paresis

Development of a smart glove for affordable diagnosis of str...

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2020 International Conference on Computer, Electrical and Communication engineering, ICCECE 2020

作者： Dutta, Debeshi Sen, Soumen Aruchamy, Srinivasan Mandal, Soumen Acad. of Sci. and Innov. Research CSIR-Central Mechanical Engineering Research Institute Durgapur West Bengal India Robotics and Automation Group CSIR-Central Mechanical Engineering Research Institute Durgapur West Bengal India Skill and Innovation Promotion Group CSIR-Central Mechanical Engineering Research Institute Durgapur West Bengal India

ISBN: (纸本)9781728144757

Stroke is the third highest cause of disability-adjusted-life-years (DALYs) and is becoming an important cause of disability in low-and-middleincome countries (LMICs). It has been found that in developing countries, especially in rural areas, patients suffering from disabilities due to stroke do not receive appropriate on-time treatment due to infrastructural limitations and financial barriers. Conventional rehabilitation management systems fail to cater the demanding requirements thereby arousing the need for evolution of wearable m-Health devices for uninterrupted health monitoring of patients with upper extremity paresis. In the present research, we have developed an instrumented glove incorporated with wearable sensors (bend sensors, pressure sensors, and accelerometers) for continuous monitoring of activities of daily living (ADLs) by capturing and transmitting sensory information related to finger bend angle, tip pressure, and acceleration or orientation while doing specified grasps. The sensors were calibrated using standard instruments before installation. Two subjects, a healthy individual and an individual suffering from upper extremity disability after stroke impaired, were employed for experimental validation. The subjects were instructed to perform certain pre-defined tasks and the related finger bending angles, finger-tip pressures, and acceleration were recorded. The trend of the dataset obtained was graphically visualized and analyzed for statistical parameters like mean, variance, maxima, and minima, leading to a generation of appreciably distinguishable results that discriminated against a stroke patient from a healthy individual. Therefore, the present glove-based stroke diagnosis method can be adopted for an affordable and efficient stroke rehabilitation process while promoting m-health at the same time. © 2020 IEEE.

关键词： Wearable sensors

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