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International Conference on Advanced systems and Electric Technologies (IC_ASET)

作者： Lazhar Manai Donia Hakiri Mongi Besbes Higher Institute of Information and Communication Technologies University of Carthage Hammam Chatt Tunisia Laboratory of Robotics Informatics and Complex Systems National Engineering School of Tunis University of Tunis Tunis Tunisia

ISBN: (数字)9781728163567

ISBN: (纸本)9781728163574

In this paper a control strategy using backstepping technique for multilevel inverter based active power filter control is developed. Performances comparison between backstepping strategy and PI regulators based methods is provided. Simulation results prove the robustness and accuracy of proposed technique compared with conventional methods.

关键词： Capacitors Backstepping Active filters Power harmonic filters Voltage control Multilevel inverters Harmonic analysis

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Walking Stabilization of the Passive Bipedal Compass robot using a Second Explicit Expression of the Controlled Poincaré Map

Walking Stabilization of the Passive Bipedal Compass robot u...

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International Conference on Sciences and Techniques of Automatic Control and Computer engineering (STA)

作者： Wafa Znegui Hassène Gritli Safya Belghith Laboratory of Robotics Informatics and Complex Systems (RISC Lab - LR16ES07) National Engineering School of Tunis Université de Tunis El Manar Tunis Tunisia

ISBN: (数字)9781728188157

ISBN: (纸本)9781728188164

This paper illustrates a stabilization approach of the passive bipedal locomotion of the compass-gait biped model based on an exclusively developed enhanced design of the closed form of the Controlled Poincaré Map (CPM). The followed technique relies on transforming the impulsive hybrid nonlinear dynamics of the passive motion into a linear form around a period-1 limit cycle. Forward, we simplify the complicated resulted expression using the second order of the Taylor Series. This technique, enables us to design a closed form of the CPM. The control of the passive bipedal locomotion starts with the identification of the period-1 fixed point of the non-CPM and continues with the determination of the linearized PM around such fixed point. Next, a feedback controller is adopted to stabilize this identified fixed point. Some simulation results are provided at the end to illustrate the efficiency of the control process of the passive walking motion of the compass-gait robot model.

关键词： Legged locomotion Simulation Process control Taylor series Nonlinear dynamical systems Compass Robots

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Haptic display for virtual reality: progress and challenges

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Virtual Reality & Intelligent Hardware 2019年第2期1卷 136-162页

作者： Dangxiao WANG Yuan GUO Shiyi LIU Yuru ZHANG Weiliang XU Jing XIAO State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100083China Beijing Advanced Innovation Center for Biomedical Engineering Beihang UniversityBeijing 100083China Peng Cheng Laboratory Shenzhen 518055China Department of Mechanical Engineering University of AucklandAuckland 1142New Zealand School of Computer Science and the Robotics Engineering Program Worcester Polytechnic InstituteWorcesterMA 01609-2280USA

Immersion, interaction, and imagination are three features of virtual reality (VR). Existing VR systems possess fairly realistic visual and auditory feedbacks, and however, are poor with haptic feedback, by means of which human can perceive the physical world via abundant haptic properties. Haptic display is an interface aiming to enable bilateral signal communications between human and computer, and thus to greatly enhance the immersion and interaction of VR systems. This paper surveys the paradigm shift of haptic display occurred in the past 30 years, which is classified into three stages, including desktop haptics, surface haptics, and wearable haptics. The driving forces, key technologies and typical applications in each stage are critically reviewed. Toward the future high-fidelity VR interaction, research challenges are highlighted concerning handheld haptic device, multimodal haptic device, and high fidelity haptic rendering. In the end, the importance of understanding human haptic perception for designing effective haptic devices is addressed.

关键词： Haptic display Virtual reality Desktop haptics Surface haptics Wearable haptics Multimodal haptics

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Determination of the Correlation between Process Parameters and Kerf Characteristics in Abrasive Waterjet Milling of High Strength 7075-T6 Aluminum Alloy

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Procedia Manufacturing 2020年 51卷 812-817页

作者： Panagiotis Karmiris-Obratański Rafał Kudelski Nikolaos E. Karkalos Angelos P. Markopoulos AGH University of Science and Technology Faculty of Mechanical Engineering and Robotics Department of Manufacturing Systems al. Mickiewicza 30 30-059 Cracow Poland National Technical University of Athens School of Mechanical Engineering Laboratory of Manufacturing Technology Heroon Polytechniou 9 15780 Athens Greece

Non-conventional manufacturing processes are often advantageous compared to conventional ones, as they can achieve high productivity in demanding cases. Abrasive waterjet (AWJ) machining is one of the most established non-conventional machining processes, which can achieve high material removal rates without leading to undesired workpiece material alterations and can render a large variety of shapes. In the present work, experiments regarding the AWJ milling of high strength 7075-T6 aluminum alloy are conducted with a view to correlate the process parameters, such as waterjet pressure, jet standoff distance, jet traverse speed and abrasive mass flow rate with depth of penetration, width and taper angle of the produced kerf. After the correlation between input and output parameters of the process is established, statistical analysis enables the determination of the influence of input parameters on output quantities and finally, appropriate process conditions for the regulation of depth of cut and kerf characteristics are derived.

关键词： Abrasive waterjet milling aluminum 7075-T6 depth of penetration kerf width kerf taper angle

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Super-resolution multicolor fluorescence microscopy enabled by an apochromatic super-oscillatory lens with extended depth-of-focus

arXiv

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arXiv 2022年

作者： Li, Wenli He, Pei Fan, Yulong Du, Yangtao Gao, Bo Chu, Zhiqin An, Chengxu Lei, Dangyuan Yuan, Weizheng Yu, Yiting Research & Development Institute of Northwestern Polytechnical University in Shenzhen College of Mechanical Engineering Ningbo Institute of Northwestern Polytechnical University Northwestern Polytechnical University Xi'An710072 China Northwestern Polytechnical University Xi'An710072 China Shaanxi Province Key Laboratory of Micro and Nano Electro-Mechanical Systems Northwestern Polytechnical University Xi'An710072 China Department of Materials Science and Engineering City University of Hong Kong 999077 Hong Kong The Institute of Ai and Robotics Fudan University Shanghai200433 China Key Laboratory of Spectral Imaging Technology of Chinese Academy of Sciences Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xian710119 China Department of Electrical and Electronic Engineering Joint Appointment with School of Biomedical Sciences The University of Hong Kong 999077 Hong Kong

Multicolor super-resolution imaging remains an intractable challenge for both far-field and near-field based super-resolution techniques. Planar super-oscillatory lens (SOL), a far-field subwavelength-focusing diffractive lens device, holds great potential for achieving sub-diffraction-limit imaging at multiple wavelengths. However, conventional SOL devices suffer from a numerical aperture (NA) related intrinsic tradeoff among the depth of focus (DoF), chromatic dispersion and focus spot size, being an essential characteristics of common diffractive optical elements. Typically, the limited DoF and significant chromatism associated with high NA can lead to unfavorable degradation of image quality although increasing NA imporves the resolution. Here, we apply a multi-objective genetic algorithm (GA) optimization approach to design an apochromatic binary-phase SOL that generates axially jointed multifoci concurrently having prolonged DoF, customized working distance (WD) and suppressed side-lobes yet minimized main-lobe size, optimizing the aforementioned NA-dependent tradeoff. Experimental implementation of this GA-optimized SOL demonstrates simultaneous focusing of blue, green and red light beams into an optical needle of ∼0.5λ in diameter and >10λ in length (DoF) at 428 μm WD, resulting in an ultimate resolution better than λ/3 in the lateral dimension. By integrating this apochromatic SOL device with a commercial fluorescence microscope, we employ the optical needle to perform, for the first time, three-dimensional super-resolution multicolor fluorescence imaging of the "unseen" fine structure of neurons at one go. The present study provides not only a practical route to far-field multicolor super-resolution imaging but also a viable approach for constructing imaging systems avoiding complex sample positioning and unfavorable photobleaching. Copyright © 2022, The Authors. All rights reserved.

关键词： Needles

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Design and Experimental Study of Bidirectional Deformable Hexapod Robot

Design and Experimental Study of Bidirectional Deformable He...

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IEEE International Conference on Cyber Technology in Automation, Control, and Intelligent systems

作者： Pengcheng Zhu Aibin Zhu Muhammad Affan Arif Han Mao Zhifu Guo Institute of Robotics & Intelligent Systems Shaanxi Key Laboratory of Intelligent Robots Xi'an Jiaotong University Xi'an China Institute of Robotics & Intelligent Systems Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Xi'an China Taiyuan Institute Co. Ltd. of China Coal Technology and Engineering Group Taiyuan Shanxi China

ISBN: (数字)9781728190105

ISBN: (纸本)9781728190112

The hexapod robot simulates the movement mode of many kinds of insects and mammals through bionics, it has a high performance in complex environment. In this paper, a bidirectional deformable foot for hexapod robot was designed, and the influence of deformable foot pitch on the maximum stress of a spring steel with deformable angle is analyzed by finite element simulation, and a prototype was designed. Finally, the motion performance of the hexapod robot was verified by using C-legged, and the synchronized gait on flat ground, triangle gait on flat ground, jumping experiment of the hexapod robot was designed, which proved that the hexapod robot could reach the expected design goal.

关键词： Robots Stress Strain Legged locomotion Steel Springs Foot

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Surface Topography of Ti 6Al 4V ELI after High Power EDM

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Procedia Manufacturing 2020年 47卷 788-794页

作者： Panagiotis Karmiris-Obratański Krzysztof Zagórski Jacek Cieślik Emmanouil Lazaros Papazoglou Angelos Markopoulos AGH University of Science and Technology Faculty of Mechanical Engineering and Robotics Department of Manufacturing Systems al. Mickiewicza 30 30-059 Cracow Poland National Technical University of Athens School of Mechanical Engineering Laboratory of Manufacturing Technology Heroon Polytechniou 9 15780 Athens Greece

Titanium alloys find extensive applications in the modern aerospace and offshore industry, as well in the field of biomedical implants. Nevertheless, the titanium inherent thermo-physical properties (low thermal conductivity and high chemical reactivity) make it a hard to machine material. For the efficient machining of titanium alloys, non-conventional machining processes are employed. Electrical Discharge Machining (EDM) is a non-contact machining process, in which the material removal occurs through repetitive electrical sparks. The capabilities of machining any electrically conductive material, regardless of its thermo-physical and other properties, render it as one of the most widely used non-conventional machining processes. As titanium alloys are used in high-quality parts and products, the integrity and texture of the machined surface constitute an essential parameter. The current study presents an experimental investigation of the surface texture and integrity of Ti6Al4V ELI after its machining with high power EDM. Namely, a full-scale experiment has been carried out, for pulse currents up to 65A and pulse-on time up to 200 μs, using graphite electrode. The surface texture (ST) and integrity has been estimated in terms of arithmetic mean height (Sa), the maximum height of scale-limited surface (Sz), maximum peak height (Sp), maximum pit height (Sv) and skewness of the scale-limited surface (Ssk). Additionally, through microscopy observation, the surface topography and integrity have been estimated, distinguishing and characterizing the surface cracks and micro-cracks. For all the above mentioned ST parameters, an Analysis of Variance (ANOVA) test has been performed.

关键词： Electrical Discharge Machining Titanium alloy Surface topography high power

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A Spherical Mobile Robot Driven by Eccentric Pendulum and Self-stabilizing by Flywheel*

A Spherical Mobile Robot Driven by Eccentric Pendulum and Se...

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International Conference on Ubiquitous Robots and Ambient Intelligence (URAI)

作者： Han Mao Aibin Zhu Yao Tu Zheng Zhang Dangchao Li Yulin Zhang Zhifu Guo Institute of Robotics & Intelligent Systems Shaanxi Key Laboratory of Intelligent Robots Xi'an Jiaotong University Xi'an China Institute of Robotics & Intelligent Systems Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi'an Jiaotong University Xi'an China Taiyuan Institute Co. Ltd. of China Coal Technology and Engineering Group Taiyuan Shanxi China

ISBN: (数字)9781728157153

ISBN: (纸本)9781728157160

Aiming at the problem of insufficient stability of the existing spherical robot, a spherical robot driven by eccentric pendulums and self-stabilizing by flywheel is proposed in this paper. The robot is driven by the gravity shift of the pendulum and its stability is improved by flywheels rotating at high speed. This paper designed the structure of the robot and established a three-dimensional model in SolidWorks. After finishing the spherical robot prototype, its motion performance is verified by experiment. According to the experimental results, the maximum climbing angle of the spherical robot driven only by the eccentricity of the gravity pendulum is 7°, and the stability can be significantly improved when the flywheel is enabled. With fast braking of the flywheel, the robot can climb over the obstacles to the instantaneous climbing angle of 28° and move steadily in rugged terrain.

关键词： Flywheels Robot kinematics Mobile robots Acceleration Gears Gravity

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Intention-detection strategies for upper limb exosuits: model-based myoelectric vs dynamic-based control

Intention-detection strategies for upper limb exosuits: mode...

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IEEE/RAS-EMBS International Conference on Biomedical robotics and Biomechatronics (BioRob)

作者： Nicola Lotti Michele Xiloyannis Francesco Missiroli Domenico Chiaradia Antonio Frisoli Vittorio Sanguineti Lorenzo Masia Institut für Technische Informatik (ZITI) Heidelberg University Heidelberg Deutschland Institute of Robotics and Intelligent Systems ETH Zürich Zürich Switzerland TeCIP Institute PERCRO Laboratory Scuola Superiore Sant’Anna Pisa Italy Dept. Informatics Bioengineering Robotics and Systems Engineering University of Genoa Genova Italy

ISBN: (数字)9781728159072

ISBN: (纸本)9781728159089

The cognitive human-robot interaction between an exosuit and its wearer plays a key role in determining both the biomechanical effects of the device on movements and its perceived effectiveness. There is a lack of evidence, however, on the comparative performance of different control methods, implemented on the same device. Here, we compare two different control approaches on the same robotic suit: a model-based myoelectric control (myoprocessor), which estimates the joint torque from the activation of target muscles, and a dynamic-based control that provides support against gravity using an inverse dynamic model. Tested on a cohort of four healthy participants, assistance from the exosuit results in a marked reduction in the effort of muscles working against gravity with both control approaches (peak reduction of 68.6±18.8%, for the dynamic arm model and 62.4±25.1% for the myoprocessor), when compared to an unpowered condition. Neither of the two controllers had an affect on the performance of their users in a joint-angle tracking task (peak errors of 15.4° and 16.4° for the dynamic arm model and myoprocessor, respectively, compared to 13.1o in the unpowered condition). However, our results highlight the remarkable adaptability of the myoprocessor to seamlessly adapt to changing external dynamics.

关键词： Muscles Torque Elbow Robots Electromyography Task analysis Gravity

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Regret bounds for adaptive nonlinear control

arXiv

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arXiv 2020年

作者： Boffi, Nicholas M. Tu, Stephen Slotine, Jean-Jacques E. John A. Paulson School of Engineering and Applied Sciences Harvard University United States Google Brain Robotics United States Nonlinear Systems Laboratory Massachusetts Institute of Technology United States

We study the problem of adaptively controlling a known discrete-time nonlinear system subject to unmodeled disturbances. We prove the first finite-time regret bounds for adaptive nonlinear control with matched uncertainty in the stochastic setting, showing that the regret suffered by certainty equivalence adaptive control, compared to an oracle controller with perfect knowledge of the unmodeled disturbances, is upper bounded by (formula presented) in expectation. Furthermore, _we show that when the input is subject to a k timestep delay, the regret degrades to (formula presented). Our analysis draws connections between classical stability notions in nonlinear control theory (Lyapunov stability and contraction theory) and modern regret analysis from online convex optimization. The use of stability theory allows us to analyze the challenging infinite-horizon single trajectory setting. Copyright © 2020, The Authors. All rights reserved.

关键词： Stochastic systems

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