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OmBURo: A Novel Unicycle Robot with Active Omnidirectional Wheel

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OmBURo: A Novel Unicycle Robot with Active Omnidirectional W...

IEEE International Conference on robotics and Automation (ICRA)

作者： Junjie Shen Dennis Hong Robotics and Mechanisms Laboratory the Department of Mechanical and Aerospace Engineering University of California Los Angeles CA USA

ISBN: (数字)9781728173955

ISBN: (纸本)9781728173962

A mobility mechanism for robots to be used in tight spaces shared with people requires it to have a small footprint, to move omnidirectionally, as well as to be highly maneuverable. However, currently there exist few such mobility mechanisms that satisfy all these conditions well. Here we introduce Omnidirectional Balancing Unicycle Robot (OmBURo), a novel unicycle robot with active omnidirectional wheel. The effect is that the unicycle robot can drive in both longitudinal and lateral directions simultaneously. Thus, it can dynamically balance itself based on the principle of dual-axis wheeled inverted pendulum. This paper discloses the early development of this novel unicycle robot involving the overall design, modeling, and control, as well as presents some preliminary results including station keeping and path following. With its very compact structure and agile mobility, it might be the ideal locomotion mechanism for robots to be used in human environments in the future.

关键词： Wheels Mobile robots Gears Friction Mathematical model Energy loss

Tacchi 2.0: A Low Computational Cost and Comprehensive Dynamic Contact Simulator for Vision-based Tactile Sensors

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arXiv 2025年

作者： Sun, Yuhao Zhang, Shixin Li, Wenzhuang Zhao, Jie Shan, Jianhua Shen, Zirong Chen, Zixi Sun, Fuchun Guo, Di Fang, Bin School of Artificial Intelligence Beijing University of Posts and Telecommunications Beijing100083 China Beijing100083 China School of International Beijing University of Posts and Telecommunications Beijing100876 China School of Mechanical Engineering Anhui University of Technology China Zhili College Tsinghua University Beijing100084 China Biorobotics Institute The Department of Excellence in Robotics and AI Scuola Superiore Sant’Anna Pisa56127 Italy Institute for Artificial Intelligence Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology Tsinghua University Beijing100084 China

With the development of robotics technology, some tactile sensors, such as vision-based sensors, have been applied to contact-rich robotics tasks. However, the durability of vision-based tactile sensors significantly increases the cost of tactile information acquisition. Utilizing simulation to generate tactile data has emerged as a reliable approach to address this issue. While data-driven methods for tactile data generation lack robustness, finite element methods (FEM) based approaches require significant computational costs. To address these issues, we integrated a pinhole camera model into the low computational cost vision-based tactile simulator Tacchi that used the Material Point Method (MPM) as the simulated method, completing the simulation of marker motion images. We upgraded Tacchi and introduced Tacchi 2.0. This simulator can simulate tactile images, marked motion images, and joint images under different motion states like pressing, slipping, and rotating. Experimental results demonstrate the reliability of our method and its robustness across various vision-based tactile sensors. © 2025, CC BY.

关键词： Pinhole cameras

FaSTrack: A modular framework for real-time motion planning and guaranteed safe tracking

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arXiv 2021年

作者： Chen, Mo Herbert, Sylvia L. Hu, Haimin Pu, Ye Fisac, Jaime F. Bansal, Somil Han, SooJean Tomlin, Claire J. School of Computing Science Simon Fraser University Canada Department of Mechanical and Aerospace Engineering UC San Diego United States Department of Electrical Engineering Princeton University United States Department of Electrical and Electronic Engineering University of Melbourne Australia Department of Electrical Engineering and Computer Sciences UC Berkeley United States Control and Dynamical Systems Program California Institute of Technology United States

Real-time, guaranteed safe trajectory planning is vital for navigation in unknown environments. However, real-time navigation algorithms typically sacrifice robustness for computation speed. Alternatively, provably safe trajectory planning tends to be too computationally intensive for real-time replanning. We propose FaSTrack, Fast and Safe Tracking, a framework that achieves both real-time replanning and guaranteed safety. In this framework, real-time computation is achieved by allowing any trajectory planner to use a simplified planning model of the system. The plan is tracked by the system, represented by a more realistic, higher-dimensional tracking model. We precompute the tracking error bound (TEB) due to mismatch between the two models and due to external disturbances. We also obtain the corresponding tracking controller used to stay within the TEB. The precomputation does not require prior knowledge of the environment. We demonstrate FaSTrack using Hamilton-Jacobi reachability for precomputation and three different real-time trajectory planners with three different tracking-planning model pairs. Copyright © 2021, The Authors. All rights reserved.

关键词： Trajectories

Bulk high-entropy hexaborides

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arXiv 2021年

作者： Qin, Mingde Yan, Qizhang Liu, Yi Wang, Haoren Wang, Chunyang Lei, Tianjiao Vecchio, Kenneth S. Xin, Huolin L. Rupert, Timothy J. Luo, Jian Program of Materials Science and Engineering Department of NanoEngineering University of California San Diego San diegoCA92093 United States Department of Physics and Astronomy University of CaliforniaIrvine IrvineCA92697 United States Department of Materials Science and Engineering Department of Mechanical and Aerospace Engineering University of California Irvine IrvineCA92697 United States

For the first time, a group of CaB6-typed cubic rare earth high-entropy hexaborides have been successfully fabricated into dense bulk pellets (>98.5% in relative densities). The specimens are prepared from elemental precursors via in-situ metal-boron reactive spark plasma sintering. The sintered bulk pellets are determined to be single-phase without any detectable oxides or other secondary phases. The homogenous elemental distributions have been confirmed at both microscale and nanoscale. The Vickers microhardness are measured to be 16-18 GPa at a standard indentation load of 9.8 N. The nanoindentation hardness and Young's moduli have been measured to be 19-22 GPa and 190-250 GPa, respectively, by nanoindentation test using a maximum load of 500 mN. The material work functions are determined to be 3.7-4.0 eV by ultraviolet photoelectron spectroscopy characterizations, which are significantly higher than that of LaB6. © 2021, CC BY.

关键词： Pelletizing

Assessment of HVAF thermally sprayed coatings: Unraveling microstructural, electrochemical, and tribological performance using glass former Fe-Cr-Mo-Nb-B feedstock powder

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Journal of Alloys and Metallurgical Systems

Journal of Alloys and Metallurgical Systems 2024年 6卷

作者： Mota, I.G.C. Koga, G.Y. Rodrigues, L.C.M. Nascimento, A.R.C. Ettouil, F.B. Ferreira, T. Coimbrão, D.D. Kiminami, C.S. Bolfarini, C. Moreau, C. Botta, W.J. Federal University of São Carlos Graduate Program in Materials Science and Engineering Rod. Washington Luis km 235 SP São CarlosCEP 13565-905 Brazil Federal University of São Carlos Department of Materials Science and Engineering Rod. Washington Luis km 235 SP São CarlosCEP 13565-905 Brazil Federal University of Sao Carlos Rodovia Washington Luiz km 235 SP-310 São Paulo São Carlos13565-905 Brazil Thermal Spray and Multiphase Flow Laboratory Concordia University MontrealQCH3G 1M8 Canada Department of Mechanical Industrial and Aerospace Engineering Concordia University 1455 de Maisonneuve Blvd. W MontrealQCH3G 1M8 Canada

In this paper the microstructural features of the glass former Fe68Cr8Mo4Nb4B16 coatings are unveiled and related to their electrochemical and tribological responses. The coating was mostly glassy with some embedded borides (M3B2, M2B-tetragonal;M being the metallic elements of the alloy) and ferrite. The tribological behavior of the HVAF coated sample, characterized by a thickness of about 200 µm, ∼6% porosity and a Vickers hardness of 357 HV0.5, was assessed in a sphere-on-plate configuration, revealing a specific wear rate of approximately 5 ×10−4 mm3∙N−1m−1. The wear mechanism was dominated by delamination caused by fragile intersplats. The corrosion resistance of HVAF coatings was evaluated in 0.6 M NaCl solution and compared with the results obtained for the crystalline Fe68Cr8Mo4Nb4B16 ingot, produced by melting in an induction furnace, and for the AISI 1020 steel substrate. The HVAF coating showed satisfactory corrosion resistance compared to the carbon steel substrate and the crystalline ingot, with the highest corrosion potential, Ecorr, values (−533 mVSCE) and the lowest corrosion current density, icorr, (10−6 A∙cm−2) followed by a clear passivation window upon anodic polarization in 0.6 M NaCl solution. Evaluations of HVAF coating showed a higher glassy content compared to the gas-atomized feedstock powders. This suggests that during spraying, certain particles were molten and experienced cooling rates adequate to inhibit crystallization, resulting in the freezing of the supercooled liquid. This phenomenon contributes to the good corrosion resistance observed in the present work and offers an opportunity to enhance the electrochemical behavior of HVAF coatings. © 2024 The Authors

关键词： Wear of materials

Non-invasive oscillatory neuromodulation of cortical vestibular functions: method and future implications

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Brain Stimulation 2023年第1期16卷 266-267页

作者： Giannotta, Alessandro Rossi, Simone Cinti, Alessandra Viberti, Francesca Benelli, Alberto Neri, Francesco De Monte, David Romanella, Sara Smeralda, Carmelo Donniacuo, Aniello Prattichizzo, Domenico Santarnecchi, Emiliano Mandalà, Marco Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab) Unit of Neurology and Clinical Neurophysiology Department of Medicine Surgery and Neuroscience University of Siena Italy Oto-Neuro-Tech Conjoined Lab Policlinico Le Scotte University of Siena Italy Otolaryngology Department of Medicine Surgery and Neuroscience Neurology and Clinical Neurophysiology Section University of Siena Italy Siena Robotics and Systems (SiRS) Lab Department of Information Engineering and Mathematics University of Siena Siena Italy Precision Neuroscience & Neuromodulation Program Massachusetts General Hospital Harvard Medical School Boston MA USA

Structural changes induced by electric currents in a single crystal of Pr2CuO4

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arXiv 2023年

作者： Roy, Susmita Ye, Feng Morgan, Zachary Mathur, Kabir Parulekar, Anish Jalali, Syed I.A. Zhang, Yu Cao, Gang Kaneko, Nobu-Hisa Greven, Martin Raj, Rishi Reznik, Dmitry Department of Physics University of Colorado at Boulder BoulderCO80309 United States Neutron Scattering Division Oak Ridge National Laboratory Oak RidgeTN37830 United States Materials Science and Engineering Program Department of Mechanical Engineering University of Colorado Boulder BoulderCO80309 United States Ibaraki Tsukuba305-8563 Japan School of Physics and Astronomy University of Minnesota MinneapolisMN55455 United States Center for Experiments on Quantum Materials University of Colorado at Boulder BoulderCO80309 United States

We demonstrate a novel approach to the structural and electronic property modification of perovskites, focusing on Pr2CuO4, an undoped parent compound of a class of electron-doped copper-oxide superconductors. Currents were passed parallel or perpendicular to the copper-oxygen layers with the voltage ramped up until a rapid drop in the resistivity was achieved, a process referred to as"flash". The current was then further increased tenfold in current-control mode. This state was quenched by immersion into liquid nitrogen. Flash can drive many compounds into different atomic structures with new properties, whereas the quench freezes them into a_long-lived state. Single-crystal neutron diffraction of as-grown and modified Pr2CuO4 revealed a √10x√10 superlattice due to oxygen-vacancy order. The diffraction peak intensities of the superlattice of the modified sample were significantly enhanced relative to the pristine sample. Raman-active phonons in the modified sample were considerably sharper. Measurements of electrical resistivity, magnetization and two-magnon Raman scattering indicate that the modification affected only the Pr-O layers, but not the Cu-O planes. These results point to enhanced oxygen-vacancy order in the modified samples well beyond what can be achieved without passing electrical current. Our work opens a new avenue toward electric field/quench control of structure and properties of layered perovskite oxides. © 2023, CC BY.

关键词： Electronic properties

Interface Rotation in Cu/Nb Accumulative Roll Bonded (ARB) Nanolaminates

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SSRN

SSRN 2022年

作者： Radchenko, Ihor Zhu, Wenxin Qing, Liu Navarro, Etienne Sahay, Rahul Lee, Pooi See Raghavan, Nagarajan Thomas, Olivier Budiman, Arief Suriadi Chen, Kai State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University Xi’an China School of Materials Science and Engineering Nanyang Technological University Singapore639798 Singapore Nanyang Technological University Temasek Laboratories@NTU 637553 Singapore Aix Marseille Université Université de Toulon CNRS IM2NP Marseille France Xtreme Mechanics Lab 8 Somapah Road Singapore487372 Singapore Singapore487372 Singapore Department of Manufacturing and Mechanical Engineering and Technology Oregon Institute of Technology Klamath FallsOR97601 United States Industrial Engineering Department BINUS Graduate Program—Master of Industrial Engineering Bina Nusantara University Jakarta11480 Indonesia

Metal-metal nanolaminates made by accumulative roll bonding (ARB) is a developing new class of structural nanocomposites that possesses high strength, good ductility, and can also be produced in bulk. These nanolaminates exhibit strong crystallographic textures and mechanical anisotropy. Yet, their mechanical properties are often measured only along rolling direction (RD). Using in situ pillar compression, we show that in-plane shear deformation mechanism in Cu(63 nm)/Nb(63 nm) ARB nanolaminate strongly depends on the shear direction. Plastic shear along the RD abruptly changes into crystallographic rotation and later into interface shear as the shear direction deviates away from the RD. The observed shear mechanisms are driven by competition between different slip systems in Cu layers and at the interface. We expect similar deformation anisotropy to happen in other ARB nanolaminates with sharp texture and interface orientation. Comprehensive characterization of such nanolaminates may require considering more than just the usual rolling/transverse/normal direction anisotropy. © 2022, The Authors. All rights reserved.

关键词： Anisotropy

A lobster-inspired hybrid actuator with rigid and soft components

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arXiv 2020年

作者： Chen, Yaohui Le, Sing Tan, Qiao Chu Lau, Oscar Song, Chaoyang Sustainable and Intelligent Robotics Group Department of Mechanical Engineering Monash University ClaytonVIC3800 Australia

Soft actuators have drawn significant attentions from researchers with an inherently compliant design to address the safety issues in physical human-robot interactions. However, they are also vulnerable and pose new challenges in the design, fabrication, and analysis due to their inherent material softness. In this paper, a novel hybrid actuator design is presented with bio-inspirations from the lobster, or crustaceans in a broader perspective. We enclose a soft chamber with rectangular cross-section using a series of articulated rigid shells to produce bending under pneumatic input. By mimicking the shell pattern of lobsters’ abdomen, foldable rigid shells are designed to provide the soft actuator with full protection throughout the motion range. The articulation of the rigid shells predefines the actuator’s bending motions. As a result, the proposed design enables one to analyze this hybrid actuator with simplified quasi-static models and rigid-body kinematics, which are further validated by mechanical tests. This paper demonstrates that the proposed hybrid actuator design is capable of bridging the major design drawbacks of the entirely rigid and soft robots while preserving their engineering merits in performance. Copyright © 2020, The Authors. All rights reserved.

关键词： Shells (structures)