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The Impact of Complex Periodic Structures on the Acoustic Performance of Architectural Materials: An Interdisciplinary Approach 1

引用

3rd International Conference on Innovation in Engineering, ICIE 2024

作者： Benchea, Marcelin Bujoreanu, Carmen Şerbănoiu, Bogdan Chiriac, Elena Adelina Ianuş, Gelu Mechanical Engineering Faculty Mechatronics and Robotics Department "Gheorghe Asachi" Technical University of Iaşi 43 Prof. Dr. Doc. D. Mangeron Iaşi700050 Romania Architecture Faculty "Gheorghe Asachi" Technical University of Iaşi Iaşi Romania

ISBN: (数字)9783031626845

ISBN: (纸本)9783031626838

This study explores the use of minimal surfaces in enhancing the acoustic properties of architectural structures. It specifically focuses on analyzing the sound scattering coefficient to understand how these surfaces can improve the overall acoustic environment in buildings. The paper delves into the examination of complex periodic structures, which are noted for their geometric efficiency and aesthetic value, and assesses their capabilities in reducing unwanted sound reflections and enhancing sound quality in architectural spaces. The core of this research lies in evaluating the effectiveness of minimal surfaces in addressing acoustic challenges. To achieve this, experimental measurements were conducted to analyze the sound scattering properties of minimal surfaces and their subsequent impact on the acoustic environment. These measurements adhere to the ISO 10534-1:1998 and ISO 17497-1:2004 standards, which outline the methodologies for experimental procedures in determining sound absorption and scattering characteristics. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.

关键词： Acoustic properties

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Static Characteristics of Zero-Current-Switching Quasi-Resonant Boost Converter under Variation of Resonant Circuit and Load Parameters 8

Static Characteristics of Zero-Current-Switching Quasi-Reson...

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8th IEEE International Conference on Energy Smart Systems, ESS 2022

作者： Dymerets, Andrii V. Gorodny, Alexey N. Yershov, Roman D. Revko, Anatoliy S. Stepenko, Serhii A. Chernihiv Polytechnic National University Electronics Automation Robotics and Mechatronics Department Chernihiv Ukraine Chernihiv Polytechnic National University Electrical Engineering Information and Measurement Technologies Department Chernihiv Ukraine

ISBN: (数字)9798350334418

ISBN: (纸本)9798350399202

The impact of resonant circuit parameters on static characteristics of a half-wave boost quasi-resonant converter is investigated. The dependences of the converter voltage maximum conversion ratio under variation of resonant circuit time constant and characteristic impedance with different load impedance values are obtained by dint of multi-factor numeric simulation. The dependences of the ratio between the transistor current peak value and input current rms value under variation of resonant circuit time constant and characteristic impedance with different load impedance values are also obtained. Approximated laws described above dependencies are fitted. Results allow determining the allowable values for resonant inductance and capacitance, as well as the load impedance to keep within a zero-current-switching mode. © 2022 IEEE.

关键词： Resonant circuits

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Towards Autonomous Robotic Grasping: 3D Point Cloud Analysis with Stereo Cameras in Unpredictable Environments

Towards Autonomous Robotic Grasping: 3D Point Cloud Analysis...

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IEEE Southeastcon

作者： Shrey Patel Aiden Kovarovics Aaditya More Carrington Chun Montreal Fletcher M. Hasan Tanveer Sumit Chakravarty Razvan Voicu Dept. of Robotics & Mechatronics Engineering Kennesaw State University Marietta USA Dept. of Electrical and Computer Engineering Kennesaw State University Marietta USA

ISBN: (数字)9798331504847

ISBN: (纸本)9798331504854

Current robotic arm systems typically depend on pretrained models or function within controlled environments using known positions or fiducial markers for object manipulation. Although these methods achieve high accuracy, they face limitations due to lengthy training processes and the need for carefully controlled setups. This research introduces a methodology that leverages stereo cameras to develop a generalized algorithm aimed at overcoming these constraints and enhancing robotic manipulation in uncontrolled environments. The proposed solution utilizes an Intel RealSense stereo camera in conjunction with YOLO segmentation models for initial object identification. It combines segmentation meshes with the camera's depth values to create a detailed three-dimensional point cloud of the target object's surface. This point cloud is analyzed through Random Sample Consensus (RANSAC) and geometry-based feature extraction techniques, which allow the algorithm to approximate the object's shape as a combination of fundamental 3D forms, such as cuboids, cylinders, and spheres. A grasp point is then estimated by identifying suitable surfaces for grasping with a two-pronged gripper, followed by calculating an optimal approach angle and position kinematics for the robotic arm. This innovative approach enables robotic arm systems to autonomously adapt to various objects in uncontrolled environments, significantly expanding their practical applications. For example, the methodology could support modular robotic systems designed for sample collection in extraterrestrial missions, where adaptability and autonomous operations are essential. Ultimately, this research aims to enhance the efficiency and capabilities of robotic systems in dynamic and unpredictable settings.

关键词： Point cloud compression YOLO Training Three-dimensional displays Robot vision systems Grasping Manipulators Cameras Feature extraction Object recognition

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OFF-CLIP: Improving Normal Detection Confidence in Radiology CLIP with Simple Off-Diagonal Term Auto-Adjustment

arXiv

引用

arXiv 2025年

作者： Park, Junhyun Moon, Chanyu Lee, Donghwan Kim, Kyungsu Hwang, Minho Department of Robotics and Mechatronics Engineering DGIST Korea Republic of Department of Electrical Engineering and Computer Science DGIST Korea Republic of Seoul National University Korea Republic of

Contrastive Language-Image Pre-Training (CLIP) has enabled zero-shot classification in radiology, reducing reliance on manual annotations. However, conventional contrastive learning struggles with normal case detection due to its strict intra-sample alignment, which disrupts normal sample clustering and leads to high false positives (FPs) and false negatives (FNs). To address these issues, we propose OFF-CLIP, a contrastive learning refinement that improves normal detection by introducing an off-diagonal term loss to enhance normal sample clustering and applying sentence-level text filtering to mitigate FNs by removing misaligned normal statements from abnormal reports. OFF-CLIP can be applied to radiology CLIP models without requiring any architectural modifications. Experimental results show that OFF-CLIP significantly improves normal classification, achieving a 0.61 Area under the curve (AUC) increase on VinDr-CXR over CARZero, the state-of-the-art zero-shot classification baseline, while maintaining or improving abnormal classification performance. Additionally, OFF-CLIP enhances zero-shot grounding by improving pointing game accuracy, confirming better anomaly localization. These results demonstrate OFF-CLIP’s effectiveness as a robust and efficient enhancement for medical vision-language models. Copyright © 2025, The Authors. All rights reserved.

关键词： Radiology

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Design and Analysis of a Novel Hybrid Grasping Mode Microgripper for High Precision Tasks 9

Design and Analysis of a Novel Hybrid Grasping Mode Microgri...

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9th IEEE International Women in Engineering (WIE) Conference on Electrical and Computer Engineering, WIECON-ECE 2023

作者： Das, Tilok Kumar Shahrear, Rifat Das, Arpita Shirinzadeh, Bijan Dept. of Mechanical Engineering Chattogram Bangladesh Temple University Dept. of Electrical and Computer Engineering PhiladelphiaPA United States Monash University Robotics and Mechatronics Research Laboratory Dept. of Mechanical and Aerospace Engineering MelbourneVIC Australia

ISBN: (纸本)9798350319651

This paper represents a novel piezoelectric actuated flexure-based compliant microgripper which can perform both parallel and angular grasping regardless of the geometric surface of the objects. Two compliant bridge-type mechanisms along with two symmetrical microgripper jaws at the end of the two side arms are accommodated to construct the microgripper. The two side arms of the microgripper act as lever-type amplification mechanisms. Simultaneous actuation of two bridge-type mechanisms is needed to perform linearized parallel grasping. The symmetric design is adopted to maintain better stability. The Finite Element Analysis (FEA) has been performed to evaluate the performance of the microgripper. FEA shows that each jaw of the microgripper can achieve a displacement of 141.72 μm resulting in a total displacement of 283.44 μm with an amplification ratio of 10.7 and 0.715% parasitic motion in y-direction of the X -axis displacement during parallel grasping. Also, each jaw can achieve a displacement of 283.88 μm which results in a total displacement of 567.76 μm with an amplification ratio of 21.5 and 5.17 mrad angular rotation about the Z-axis during angular grasping. The FEA suggests that the microgripper is capable of both parallel and angular grasping/releasing tasks. © 2023 IEEE.

关键词： Piezoelectric actuators

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Investigating the Failure Mechanisms During the Epoxy-Coated Bearing Steel–Steel and Uncoated Bearing Steel–Steel Interactions (Crack Formation, Surface Tears, Schallamach-like Waves) and Their Corrosion Resistance in NaCl Environment

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Journal of Bio- and Tribo-Corrosion 2024年第4期10卷 1-21页

作者： Alavanthar, Amirthalakshmi Bhaumik, Shubrajit Paleu, Viorel Department of Science and Humanities Amrita School of Engineering Amrita Vishwa Vidyapeetham Tamil Nadu Chennai601103 India Department of Mechanical Engineering Amrita School of Engineering Amrita Vishwa Vidyapeetham Tamil Nadu Chennai601103 India Mechanical Engineering Mechatronics and Robotics Department Mechanical Engineering Faculty "Gheorghe Asachi" Technical University of Iași 43 Prof. D. Mangeron Bld Iasi700050 Romania

The anti-wear properties of coatings are important to enhance the life of the steel surfaces. Thus, understanding the wear mechanisms of any coating matrix is important while designing and choosing a new coating matrix on steel surfaces. The present work investigated the thermal, mechanical, anti-wear, and anti-corrosion performance of semi-liquid epoxy-coated EN8 steel surfaces under reciprocating motion. The semi-liquid LY556 epoxy mixed with HY951 hardener was used to coat EN8 surfaces. The tribo-tests were conducted at different loads (5 N, 10 N, 15 N, and 20 N), spindle frequencies (1 Hz, 2 Hz, 3 Hz, and 4 Hz), and temperatures (40 °C, 60 °C, 80 °C, and 100 °C), maintaining a stroke length of 15 mm. The differential scanning calorimeter readings indicated the glass transition temperature of the cured epoxy to be 80 °C with the endothermic peak at 119 °C. The thermal degradation of the cured epoxy was found to be 330 °C using a thermal gravimetric analyzer. Artificial neural network models indicated that the frictional coefficient of the coated EN 8 samples increased with an increase in load, frequency, and temperature with the minimum frictional coefficient at 40 °C (0.0767 ± 0.014). The coating peel-off was observed from 80 °C. The optical microscope and scanning electron microscope images of the coating wear scar exhibited cracks and Schallamach-like material waves. Additionally, the corrosion studies indicated a significant corrosion resistance of the coated bars even after 120 h as compared to non-coated bars. Thus, the present work will be highly beneficial in developing new anti-wear and anti-corrosive coatings for steel surfaces. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Cracks

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Kinematic Transfer Learning of Sampling Distributions for Manipulator Motion Planning

Kinematic Transfer Learning of Sampling Distributions for Ma...

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IEEE International Conference on robotics and Automation (ICRA)

作者： Peter Lehner Má ximo A. Roa Alin Albu-Schä ffer Institute of Robotics and Mechatronics German Aerospace Center (DLR) at Oberpfaffenhofen Germany

Recent research has shown that guiding sampling-based planners with sampling distributions, learned from previous experiences via density estimation, can significantly decrease computation times for motion planning. We propose an algorithm that can estimate the density from the experiences of a robot with different kinematic structure, on the same task. The method allows to generalize collected data from one source manipulator to similarly designed target manipulators, significantly reducing the computation time for new queries for the target manipulator. We evaluate the algorithm in two experiments, including a constrained manipulation task with five different collaborative robots, and show that transferring information can significantly decrease planning time.

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High-Precision 3-DOF Compliant Positioning Stage for Large Range Micro-Manipulation Applications

High-Precision 3-DOF Compliant Positioning Stage for Large R...

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IEEE International Conference of Intelligent Robotic and Control Engineering (IRCE)

作者： Ashenafi Abrham Kassa Bijan Shirinzadeh Julian Smith Department of Mechanical and Aerospace Engineering Robotics and Mechatronics Research Laboratory (RMRL) Monash University Melbourne Australia Department of Surgery Monash University Melbourne Australia

ISBN: (数字)9798350352399

ISBN: (纸本)9798350352405

This paper introduces a novel high-precision compliant mechanism-based 3-degree-of-freedom (3-DOF) positioning stage with a large range and planar layout. The design incorporates a cartwheel revolute flexure and compound basic parallelogram (CBP) prismatic flexure modules arranged in series to establish a PPR-kinematic chain. Three such kinematic chains are symmetrically arranged at 120° to each other around the output platform. This design ensures large deformation and high dynamic performance while minimizing cross-coupling and parasitic motion. The compliance matrix method (CMM) is utilized to establish the stiffness model of the designed mechanism. Computational analysis is performed to validate the developed analytical model. Moreover, the reachable workspace, inverse kinematics, and dynamic performance of the proposed stage are investigated. A workspace of 4.6 mm × 5.1 mm × 83 mrad is achieved while maintaining a high natural frequency of 58 Hz. From the analysis, the proposed stage can be adopted in micro-manipulation applications that require high-precision motion over an extended range.

关键词： Transmission line matrix methods Symmetric matrices 3-DOF Dynamics Layout Kinematics Fasteners Manufacturing Motion control Robots

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Improved Contact Stability for Admittance Control of Industrial Robots with Inverse Model Compensation

Improved Contact Stability for Admittance Control of Industr...

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IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

作者： Kangwagye Samuel Kevin Haninger Sami Haddadin Sehoon Oh Chair of Robotics and Systems Intelligence Munich Institute of Robotics and Machine Intelligence (MIRMI) Technical University Munich Munich Germany Department of Mechanical and Production Engineering Kyambogo University Kampala Uganda Department of Automation Fraunhofer IPK Berlin Germany Department of Robotics and Mechatronics Engineering DGIST Daegu Korea

ISBN: (数字)9798350377705

ISBN: (纸本)9798350377712

Industrial robots have increased payload, repeatability, and reach compared to collaborative robots, however, they have a fixed position controller and low intrinsic admittance. This makes realizing safe contact challenging due to large contact force overshoots in contact transitions and contact instability when the environment and robot dynamics are coupled. To improve safe contact on industrial robots, we propose an admittance controller with inverse model compensation, designed and implemented outside the position controller. By including both the inner loop and outer loop dynamics in its design, the proposed method achieves expanded admittance in terms of increasing both gain and cutoff frequency of the desired admittance. Results from theoretical analyses and experiments on a commercial industrial robot show that the proposed method improves rendering of the desired admittance while maintaining contact stability. We further validate this by conducting actual assembly tasks of plug insertion with fine positioning, switch insertion onto the rail, and colliding the robot end effector with random objects and surfaces, as seen at https://***/8XfkdHEdWDs.

关键词： Service robots Contacts Dynamics Cutoff frequency Observers Industrial robots Stability analysis Admittance Thermal stability Payloads

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Robust Control of a DC Motor and Load Using Quantitative Feedback Theory

Robust Control of a DC Motor and Load Using Quantitative Fee...

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International Symposium on High Capacity Optical Networks and Enabling Technologies, HONET

作者： Amir Ali Amiri Moghadam Razvan Cristian Voicu Kishan Patel Ying Wang Yusun Chang Department of Robotics & Mechatronics Engineering Kennesaw State University Atlanta Georgia

ISBN: (纸本)9781665461986

This paper reports on robust position control of a DC motor and gear system attached to a mechanical load. The dynamics of the system will be identified using the sine wave inputs and least square method. It has been found out that a single linear time invariant (LTI) model cannot perfectly predicts the behavior of the system for a range of different frequencies. So, we are using a family of LTI systems instead with parameter uncertainty. Next a robust controller will be designed using Quantitative Feedback Theory (QFT) to provide consistent robust performance for the system. The performance of the QFT controller will be validated through both simulations and experimental data and will be compared with a PID controller. It has been shown that the QFT controller has a superior performance over the PID controller in terms of tracking error.

关键词： Linear systems Uncertain systems Time-frequency analysis Smart cities Predictive models DC motors Data models

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