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Multi-Objective Optimization of High-Power Fiber Laser Cutting of Thick Mild Steel by Using Response Surface Methodology

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SSRN

SSRN 2023年

作者： Liu, Yanjie Yoshigoe, Kenji Ullah, Farhan Zhang, Shijin Zhao, Yue Shanghai Key Lab of Intelligent Manufacturing and Robotics School of Mechatronic Engineering and Automation Shanghai University Shanghai200444 China School of Software Northwestern Polytechnical University Xi’an710129 China Department of Electrical Engineering and Computer Science Embry-Riddle Aeronautical University Daytona BeachFL32114 United States

High-power continuous wave fiber laser cutting is a next-generation cutting technology for rapid prototyping and small-scale fabrication. To utilize the advantage offered by this technology in terms of high-quality cutting, the laser cutting process parameters must be optimized. In this study, separation speed experiment on thick mild steel plates was performed using a 12-kW continuous-wave multimode ytterbium-doped fiber laser, and a high-power fiber laser cutting cut-through criterion for thick carbon steel plates was proposed. The response surface method was used to model and optimize the cut quality characteristics. Material thickness, laser power, cutting speed, gas pressure, and defocus amount were selected as input factors, whereas kerf taper and material removal rate (MRR) were selected as output quality characteristics. The effects of the various factors on the kerf taper and MRR were investigated using analysis of variance, and second-order regression models were developed for the kerf taper and MRR. Furthermore, a multi-objective optimization method was used to optimize the kerf taper and MRR. The percentage errors of the validation experiments and multi-objective optimization results were 5.27% and 1.93% for the kerf taper and MRR, respectively. Moreover, the analysis revealed that the material removal mechanism and the kerf taper formation mechanism are related to the melt flow. The findings presented in this paper contribute to the improvement of quality and accuracy when cutting thick plates by using a high-power fiber laser. © 2023, The Authors. All rights reserved.

关键词： Multiobjective optimization

How to Model Brushless Electric Motors for the Design of Lightweight Robotic Systems

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arXiv 2023年

作者： Lee, Ung Hee Shepherd, Tor Kim, Sangbae De, Avik Su, Hao Gregg, Robert Mooney, Luke Rouse, Elliott Neurobionics Lab. University of Michigan Ann ArborMI48109 United States Department of Mechanical Engineering University of Michigan United States The Robotics Institute University of Michigan United States Department of Mechanical Engineering Massachusetts Institute of Technology CambridgeMA02139 United States Department of Electrical and Systems Engineering University of Pennsylvania PhiladelphiaPA19104 United States Lab of Biomechatronics and Intelligent Robotics Department of Mechanical Engineering and Aerospace Engineering North Carolina State University RaleighNC27695 United States Department of Electrical Engineering and Computer Science University of Michigan United States Dephy Inc. MaynardMA01754 United States

A key step in the development of lightweight, high performance robotic systems is the modeling and selection of permanent magnet brushless direct current (BLDC) electric motors. Typical modeling analyses are completed a priori, and provide insight for properly sizing a motor for an application, specifying the required operating voltage and current, as well as assessing the thermal response and other design attributes e.g. transmission ratio). However, to perform these modeling analyses, proper information about the motor’s characteristics are needed, which are often obtained from manufacturer datasheets. Through our own experience and communications with manufacturers, we have noticed a lack of clarity and standardization in modeling BLDC motors, compounded by vague or inconsistent terminology used in motor datasheets. The purpose of this tutorial is to concisely describe the governing equations for BLDC motor analyses used in the design process, as well as highlight potential errors that can arise from incorrect usage. We present a power-invariant conversion from phase and line-to-line reference frames to a familiar q-axis DC motor representation, which provides a "brushed" analogue of a three phase BLDC motor that is convenient for analysis and design. We highlight potential errors including incorrect calculations of winding resistive heat loss, improper estimation of motor torque via the motor’s torque constant, and incorrect estimation of the required bus voltage or resulting angular velocity limitations. A unified and condensed set of governing equations is available for designers in Appendix A. The intent of this work is to provide a consolidated mathematical foundation for modeling BLDC motors that addresses existing confusion and fosters high performance designs of future robotic systems. © 2023, CC BY-NC-ND.

关键词： Design

Full-pose Trajectory Tracking of Overactuated Multi-Rotor Aerial Vehicles with Limited Actuation Abilities

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TechRxiv

TechRxiv 2023年

作者： Hamandi, Mahmoud Al-Ali, Ismail Seneviratne, Lakmal Franchi, Antonio Zweiri, Yahya The Department of Aerospace Engineering Khalifa University of Science and Technology Abu Dhabi United Arab Emirates The Department of Mechanical Engineering Khalifa University Abu Dhabi United Arab Emirates Khalifa University of Science and Technology Abu Dhabi United Arab Emirates The Robotics and Mechatronics Lab Faculty of Electrical Engineering Mathematics and Computer Science University of Twente Enschede Netherlands The Department of Computer Control and Management Engineering Sapienza University of Rome Rome00185 Italy LAAS CNRS Université de Toulouse Toulouse31000 France Khalifa University Abu Dhabi United Arab Emirates Center for Artificial Intelligence and Robotics New York University Abu Dhabi Saadiyat Island Abu Dhabi129188 United Arab Emirates

This paper presents a novel optimization-based full-pose trajectory tracking method to control overactuated multirotor aerial vehicles with limited actuation abilities. The proposed method allocates feasible control inputs to track a reference trajectory, while ensuring the tracking of the reference position, and while tracking the closest feasible attitude. The optimization simultaneously searches for a feasible trajectory and corresponding feasible control inputs from the infinite possible solutions, while ensuring smooth control inputs. The proposed real-time algorithm is tested in extensive simulation on multiple platforms with fixed and actuated propellers. The simulation experiments show the ability of the proposed approach to exploit the complex set of feasible forces and moments of overactuated platforms while allocating smooth feasible control inputs. © 2023, CC BY.

关键词： Trajectories

InOR-Net: Incremental 3D Object Recognition Network for Point Cloud Representation

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arXiv 2023年

作者： Dong, Jiahua Cong, Yang Sun, Gan Wang, Lixu Lyu, Lingjuan Li, Jun Konukoglu, Ender The State Key Laboratory of Robotics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang110016 China The University of Chinese Academy of Sciences Beijing100049 China The Computer Science Department Northwestern University Evanston United States The Sony AI Tokyo108-0075 Japan The School of Computer Science and Engineering Nanjing University of Science and Technology Nanjing210094 China The Computer Vision Lab ETH Zurich Zürich8092 Switzerland

3D object recognition has successfully become an appealing research topic in the real-world. However, most existing recognition models unreasonably assume that the categories of 3D objects cannot change over time in the real-world. This unrealistic assumption may result in significant performance degradation for them to learn new classes of 3D objects consecutively, due to the catastrophic forgetting on old learned classes. Moreover, they cannot explore which 3D geometric characteristics are essential to alleviate the catastrophic forgetting on old classes of 3D objects. To tackle the above challenges, we develop a novel Incremental 3D Object Recognition Network (i.e., InOR-Net), which could recognize new classes of 3D objects continuously via overcoming the catastrophic forgetting on old classes. Specifically, a category-guided geometric reasoning is proposed to reason local geometric structures with distinctive 3D characteristics of each class by leveraging intrinsic category information. We then propose a novel critic-induced geometric attention mechanism to distinguish which 3D geometric characteristics within each class are beneficial to overcome the catastrophic forgetting on old classes of 3D objects, while preventing the negative influence of useless 3D characteristics. In addition, a dual adaptive fairness compensations strategy is designed to overcome the forgetting brought by class imbalance, by compensating biased weights and predictions of the classifier. Comparison experiments verify the state-of-the-art performance of the proposed InOR-Net model on several public point cloud datasets. Copyright © 2023, The Authors. All rights reserved.

关键词： Object recognition

TransHD: Spatial Transformer Features Extraction for HDC Synergetic Learning

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IEEE Transactions on Artificial Intelligence

IEEE Transactions on Artificial Intelligence 2025年

作者： Hassan, Eman Bettayeb, Meriem Halawani, Yasmin Genssler, Paul R. Tesfai, Huruy Zweiri, Yahya Amrouch, Hussam Hadjileontiadis, Leontios J. Saleh, Hani Mohammad, Baker Khalifa University System on Chip Lab Department of Computer and Information Engineering Abu Dhabi127788 United Arab Emirates Abu Dhabi University Department of Computer Science and Information Technology College of Engineering Abu Dhabi United Arab Emirates University of Dubai College of Engineering and IT Dubai United Arab Emirates Munich Institute of Robotics and Machine Intelligence Technical University of Munich TUM School of Computation Information and Technology Chair of AI Processor Design Munich Germany Abu Dhabi United Arab Emirates Stuttgart Germany Khalifa University of Science and Technology Department of Biomedical Engineering Abu Dhabi United Arab Emirates Aristotle University of Thessaloniki Department of Electrical and Computer Engineering Thessaloniki Greece

Artificial intelligence (AI) relies on pattern recognition and classification algorithms to achieve accurate and efficient decision-making. Convolutional neural networks (CNNs) are the state-of-the-art for processing 2D image data, but their high computational and data requirements limit their use in resource-constrained environments. Hyperdimensional computing (HDC) offers a lightweight alternative, excelling in 1D tasks, but struggles to achieve competitive accuracy for 2D image classification. Hybrid frameworks combining HDC with CNNs have been proposed to improve accuracy but inherit the computational demands of deep learning, making them unsuitable for edge and IoT devices. To address this, we propose TransHD, a framework integrating lightweight spatial transformer networks (STNs) with HDC to enhance image classification performance while maintaining efficiency. TransHD achieves up to 9% higher accuracy than base HDC models on MNIST and Fashion-MNIST using only 30% of the training data, and reduces computational complexity by 2.5x through optimized STN feature map usage. On resource-constrained platforms like the Raspberry Pi 4, TransHD accelerates inference times by 3.4x and improves energy efficiency by 3.2x, with an accuracy trade-off of approximately 3% compared to CNNs. This study demonstrates the potential of combining HDC with STNs to develop efficient AI solutions for IoT and edge computing, where low energy consumption and computational efficiency are critical. © 2020 IEEE.

关键词： Convolutional neural networks

Visual Perception of Robot Appearance Attributes in the Peripheral Field of View Depends on Human Observer Eye-Movement Behaviors

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Visual Perception of Robot Appearance Attributes in the Peri...

IEEE International Conference on robotics and Automation (ICRA)

作者： Kolja Kü hnlenz Barbara Kü hnlenz Department of Electrical Engineering and Computer Science Robotics Research Lab Coburg University of Applied Sciences and Art Coburg Germany Academic Center of Sciences and Humanities Coburg University of Applied Sciences and Arts Coburg Germany

This paper presents results from a study on the perception of robot attributes by human observers in their peripheral field of view depending on types of eye-movements of the latter. A between-subjects design is used, where a picture of a robot head is presented on a screen in the peripheral field of view of the participants with two conditions of eye-movements: static and pursuit. The two conditions are realized by a dot to be tracked by the participants, which is placed either in the center of the screen or moving linearly between left and right screen margins. As a subjective measure for appearance attributes, anthropomorphism is used using the multi-component Human-Robot Interaction Evaluation Scale (HRIES). Significant differences are revealed in the sociability and agency sub-scales of HRIES with respect to eye-movement behaviors. The results show, that humans perceive robot appearance attributes differently depending on whether or not pursuit eye-movements are conducted supporting the main hypothesis. Further, for pursuit movements, the scale center is rated for these sub-scales, which may indicate, that the particular robot characteristic is perceived less distinctively. No significant interactions are found for animacy and disturbance, which may be due to less applicability of these sub-scales to static images. The findings may have an impact on close interaction between humans and robots and potential anthropomorphism-related influences on task accomplishment to be considered in interaction design.

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Bananasqueezenet: A Very Fast, Lightweight Convolutional Neural Network for Diagnosis of Three Prominent Banana Leaf Diseases

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SSRN

SSRN 2023年

作者： Bhuiyan, Md Abdullahil Baki Abdullah, Hasan Muhammad Arman, Shifat E. Rahman, Sayed Saminur Al Mahmud, Kaies Department of Plant Pathology Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur1706 Bangladesh GIS and Remote Sensing Lab Department of Agroforestry and Environment Bangabandhu Sheikh Mujibur Rahman Agricultural University Gazipur1706 Bangladesh Department of Robotics and Mechatronics Engineering University of Dhaka Dhaka1000 Bangladesh Department of Computer Science and Engineering APJ Abdul Kalam Technological University Kerala695016 India

All over the world, bananas are one of the most common fruits. It accounts for nearly 16% of global fruit production. However, every year, a large amount of banana yield losses occur due to different diseases of the banana leaf. It is essential to identify these diseases at an early stage in order to increase banana production. A visual inspection is the most common method of identifying banana leaf diseases. With visual inspection, errors are common, time is a factor, and expertise is required. This study showed how deep learning and Bayesian optimization could effectively diagnose banana leaf diseases from images without any human intervention. We collected the data from various locations in Bangladesh. The dataset consists of images of three banana leaf diseases: leaf blight, Sigatoka, and Cordana. Our proposed BananaSqueezeNet model performed exceptionally well in diagnosing banana leaf diseases from the images with an overall accuracy of 0.9625, precision of 0.9653, recall of 0.9625, specificity of 0.9875, F1-score of 0.9617, and MCC of 0.9513. The BananaSqueezeNet model outperforms three other convolutional neural networks, EfficientNetB0, MobileNetV3, and ResNet-101. BananaSqueezeNet will enable banana growers to detect banana diseases early, and we hope that it will ultimately lead to an increase in banana production in Bangladesh and around the world. © 2023, The Authors. All rights reserved.

关键词： Convolutional neural networks

A Dynamic Programming Framework for Optimal Planning of Redundant Robots Along Prescribed Paths With Kineto-Dynamic Constraints

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arXiv 2022年

作者： Ferrentino, Enrico Savino, Heitor J. Franchi, Antonio Chiacchio, Pasquale University of Salerno SA Fisciano84084 Italy Ambev Robotics Lab Anheuser-Busch InBev SP Jacareí12334-480 Brazil The Robotics and Mechatronics Laboratory Faculty of Electrical Engineering Mathematics & Computer Science University of Twente Enschede7522NH Netherlands The Department of Computer Control and Management Engineering Sapienza University of Rome Rome00185 Italy

Offline optimal planning of trajectories for redundant robots along prescribed task space paths is usually broken down into two consecutive processes: first, the task space path is inverted to obtain a joint space path, then, the latter is parametrized with a time law. If the two processes are separated, they cannot optimize the same objective function, ultimately providing sub-optimal results. In this paper, a unified approach is presented where dynamic programming is the underlying optimization technique. Its flexibility allows accommodating arbitrary constraints and objective functions, thus providing a generic framework for optimal planning of real systems. To demonstrate its applicability to a real world scenario, the framework is instantiated for time-optimality on Franka Emika's Panda robot. The well-known issues associated with the execution of non-smooth trajectories on a real controller are partially addressed at planning level, through the enforcement of constraints, and partially through post-processing of the optimal solution. The experiments show that the proposed framework is able to effectively exploit kinematic redundancy to optimize the performance index defined at planning level and generate feasible trajectories that can be executed on real hardware with satisfactory results. Note to Practitioners-The common planning algorithms which consolidated over the years for generating trajectories for non-redundant robots are not adequate to fully exploit the more advanced capabilities offered by redundant robots. This is especially true in performance-demanding tasks, as for robots employed on assembly lines in manufacturing industries, repeatedly performing the same activity. Once the assembly line engineer has defined the tool path in the task space, our planning algorithm unifies inverse kinematics and time parametrization so as to bring the manipulator at its physical limits to achieve specific efficiency goals, being execution time the most typical

关键词： Robot programming

Offboard Occupancy Refinement with Hybrid Propagation for Autonomous Driving

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arXiv 2024年

作者： Shi, Hao Wang, Song Zhang, Jiaming Yin, Xiaoting Wang, Zhongdao Wang, Guangming Zhu, Jianke Yang, Kailun Wang, Kaiwei The State Key Laboratory of Extreme Photonics and Instrumentation The National Engineering Research Center of Optical Instrumentation Zhejiang University Hangzhou310027 China The School of Robotics The National Engineering Research Center of Robot Visual Perception and Control Technology Hunan University Changsha410082 China The College of Computer Science and Technology Zhejiang University Hangzhou310027 China The Institute for Anthropomatics and Robotics Karlsruhe Institute of Technology Karlsruhe76131 Germany Huawei Noah’s Ark Lab. Canada The Department of Engineering University of Cambridge CambridgeCB2 1PZ United Kingdom

Vision-based occupancy prediction, also known as 3D Semantic Scene Completion (SSC), presents a significant challenge in computer vision. Previous methods, confined to onboard processing, struggle with simultaneous geometric and semantic estimation, continuity across varying viewpoints, and single-view occlusion. Our paper introduces OccFiner, a novel offboard framework designed to enhance the accuracy of vision-based occupancy predictions. OccFiner operates in two hybrid phases: 1) a multi-to-multi local propagation network that implicitly aligns and processes multiple local frames for correcting onboard model errors and consistently enhancing occupancy accuracy across all distances. 2) the region-centric global propagation, focuses on refining labels using explicit multi-view geometry and integrating sensor bias, especially to increase the accuracy of distant occupied voxels. Extensive experiments demonstrate that OccFiner improves both geometric and semantic accuracy across various types of coarse occupancy, setting a new state-of-the-art performance on the SemanticKITTI dataset. Notably, OccFiner elevates vision-based SSC models to a level even surpassing that of LiDAR-based onboard SSC models. Furthermore, OccFiner is the first to achieve automatic annotation of SSC in a purely vision-based approach. Quantitative experiments prove that OccFiner successfully facilitates occupancy data loop-closure in autonomous driving. Additionally, we quantitatively and qualitatively validate the superiority of the offboard approach on city-level SSC static maps. The source code will be made publicly available at https://***/MasterHow/OccFiner. Copyright © 2024, The Authors. All rights reserved.

关键词： Semantic Segmentation