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IEEE International Conference on Industrial Informatics (INDIN)

作者： Ningyu Zhu Wen-Fang Xie Onur Toker Department of Mechanical Industrial and Aerospace Engineering Concordia University Montreal Canada Department of Electrical and Computer Engineering Florida Polytechnic University Lakeland USA

ISBN: (数字)9798331527471

ISBN: (纸本)9798331527488

The efficient control of serial robots in the presence of dynamic uncertainties and external disturbances is significant in many industrial applications. In this work, an adaptive sliding mode control (ASMC) approach with deep recurrent neural network (DRNN) is proposed for a 6-degree-of-freedom (6-DOF) industrial serial robot in joint space. A model-based sliding mode controller is developed to maintain the strong robustness of the robotic system. A deep recurrent neural network is designed to estimate the lumped system uncertainties in the controller. It consists of a feedforward structure through two hidden layers and a feedback loop from the output layer to the input layer, which exhibits more powerful online learning ability and dynamic property than shallow feedforward neural networks. According to Lyapunov theorem, the adaptation laws of the neural network parameters are derived, and the stability of the controller can be guaranteed. Simulation results demonstrate the effectiveness and superiority of the DRNN-based ASMC strategy regarding estimation convergence speed and trajectory tracking accuracy.

关键词： Recurrent neural networks Adaptive systems Uncertainty Service robots Trajectory tracking Simulation 6-DOF Stability analysis Feedforward neural networks Sliding mode control

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On Fixed-Time Stability for a Class of Singularly Perturbed Systems Using Composite Lyapunov Functions

On Fixed-Time Stability for a Class of Singularly Perturbed ...

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American Control Conference (ACC)

作者： Michael Tang Miroslav Krstic Jorge I. Poveda Department of Electrical and Computer Engineering University of California La Jolla CA Department of Mechanical and Aerospace Engineering University of California La Jolla CA

ISBN: (数字)9798350382655

ISBN: (纸本)9798350382662

Fixed-time stable dynamical systems are capable of achieving exact convergence to an equilibrium point within a fixed time that is independent of the initial conditions of the system. This property makes them highly appealing for designing control, estimation, and optimization algorithms in applications with stringent performance requirements. How-ever, the set of tools available for analyzing the interconnection of fixed-time stable systems is rather limited compared to their asymptotic counterparts. In this paper, we address some of these limitations by exploiting the emergence of multiple time scales in nonlinear singularly perturbed dynamical systems, where the fast dynamics and the slow dynamics are fixed-time stable on their own. By extending the so-called composite Lyapunov method from asymptotic stability to the context of fixed-time stability, we provide a novel class of Lyapunov-based sufficient conditions to certify fixed-time stability in a class of singularly perturbed dynamical systems. The results are illustrated, analytically and numerically, using a fixed-time gradient flow system interconnected with a fixed-time plant and an additional high-order example.

关键词： Asymptotic stability Sufficient conditions Heuristic algorithms Estimation Interconnected systems Stability analysis Dynamical systems

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Research on Network Performance and Availability Modeling Based on Data Link

Research on Network Performance and Availability Modeling Ba...

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2022 International Conference on Intelligent Transportation, Big Data and Smart City, ICITBS 2022

作者： Fu, Yanfang Guo, Dengdeng Zhao, Tao Qu, Shaochun Chen, Yinfan Xi'an Technological University School of Computer Science and Engineering Xi'an710021 China Northwest Institute of Mechanical & Electrical Engineering Xian Yang712099 China

ISBN: (纸本)9781665497213

As the basis of information war, military network plays a vital role in the development of war. Network availability is one of the most important performance of military network construction and operation. It is also an important index to measure the quality of system structure design and system performance stability. Therefore, based on the analysis of the factors affecting the availability of military network, starting from the basic concept of network availability and using Markov random process theory, this paper puts forward the Markov model of multi state repairable system of communication network, and analyzes and calculates the delay and throughput of military network system in Link16 data link. It provides some references for the development of military network in the future. © 2022 IEEE.

关键词： Markov processes

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LEARNING OPTIMAL CONTROL AND DYNAMICAL STRUCTURE OF GLOBAL TRAJECTORY SEARCH PROBLEMS WITH DIFFUSION MODELS

arXiv

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arXiv 2024年

作者： Graebner, Jannik Li, Anjian Sinha, Amlan Beeson, Ryne Department of Mechanical and Aerospace Engineering Princeton University NJ United States Department of Electrical and Computer Engineering Princeton University NJ United States

Spacecraft trajectory design is a global search problem, where previous work has revealed specific solution structures that can be captured with data-driven methods. This paper explores two global search problems in the circular restricted three-body problem: hybrid cost function of minimum fuel/time-of-flight and transfers to energy-dependent invariant manifolds. These problems display a fundamental structure either in the optimal control profile or the use of dynamical structures. We build on our prior generative machine learning framework to apply diffusion models to learn the conditional probability distribution of the search problem and analyze the model’s capability to capture these structures. Copyright © 2024, The Authors. All rights reserved.

关键词： Cost functions

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Laser powder bed fusion process parameters for the fabrication of unsupported overhang structures of metamaterial lattices

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CIRP Annals 2025年

作者： Wits, Wessel W. de Vos, Camill Montero-Sistiaga, Maria de Smit, Marc NLR – Royal Netherlands Aerospace Centre Marknesse Netherlands Faculty of Electrical Engineering Mathematics and Computer Science University of Twente Enschede Netherlands

Laser powder bed fusion of unsupported overhang structures, required for metamaterial lattices, are difficult to manufacture. In this study, process parameters are experimentally determined to successfully fabricate auxetic re-entrant metamaterial structures. Due to the support-less printing, higher linear energy densities compared to contour and hatch scanning are required to build continuously solidified overhang structures. Simulation results show that the melt pool width and in particular the length is enlarged, promoting loose powder attachment by denudation and balling. Auxetic re-entrant metamaterials are successfully fabricated. Impact tests show good mechanical performance and better energy absorption compared to previous studies. © 2025 The Author(s)

关键词： Metamaterials

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Characterization of the Dynamical Properties of Safety Filters for Linear Planar Systems

arXiv

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arXiv 2024年

作者： Chen, Yiting Mestres, Pol Dall’Anese, Emiliano Cortés, Jorge The Department of Electrical and Computer Engineering Boston University United States The Department of Mechanical and Aerospace Engineering The University of California San Diego United States

This paper studies the dynamical properties of closed-loop systems obtained from control barrier function-based safety filters. We provide a sufficient and necessary condition for the existence of undesirable equilibria and show that the Jacobian matrix of the closed-loop system evaluated at an undesirable equilibrium always has a nonpositive eigenvalue. In the special case of linear planar systems and ellipsoidal obstacles, we give a complete characterization of the dynamical properties of the corresponding closed-loop system. We show that for underactuated systems, the safety filter always introduces a single undesirable equilibrium, which is a saddle-point. We prove that all trajectories outside the global stable manifold of such equilibrium converge to the origin. In the fully actuated case, we discuss how the choice of nominal controller affects the stability properties of the closed-loop system. Various simulations illustrate our results. Copyright © 2024, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

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Intersection Point-Based Analysis of Neural Balance Control Strategies by Parkinson's Patients during Quiet Stance

Intersection Point-Based Analysis of Neural Balance Control ...

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American Control Conference (ACC)

作者： Gayatri Sreenivasan Chunchu Zhu Jingang Yi Department of Electrical and Computer Engineering Rutgers University Piscataway NJ USA Department of Mechanical and Aerospace Engineering Rutgers University Piscataway NJ USA

ISBN: (数字)9798350382655

ISBN: (纸本)9798350382662

This study employs intersection point height frequency analysis to quantitatively assess the balance control strategies used by individuals with Parkinson's disease (PD) during quiet stance. The changes in balance strategy are quantified using a triple inverted pendulum human model with a linear quadratic regulator as the neural balance controller. By considering both translational and angular body accelerations, we extract intersection point frequency curves that contain crucial information about the neuromuscular balance strategy of the PD patients. To contextualize our findings, we compare the observed frequency behavior with previous studies examining quiet stance in individuals without PD. This comprehensive investigation furnishes valuable insights into the disparities between the balance strategies of the PD patients and the healthy counterparts, shedding light on the influence of PD on balance control dynamics. The findings hold promising potential for applications in PD diagnostics and the development of robotic assistive devices for PD patient rehabilitation.

关键词： Performance evaluation Regulators Parkinson's disease Neuromuscular Biological system modeling Patient rehabilitation Data models

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Effect of Defocus Amount of Rotational Beam Coupled Laser on the Grooving Characteristics of Nickel-Based Superalloys 19

Effect of Defocus Amount of Rotational Beam Coupled Laser on...

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19th National Conference on Laser Technology and Optoelectronics

作者： Rao, Qi Chen, Xiaoxiao Shen, Shunquan Chen, Jianbo Zhang, Wenwu Faculty of Mechanical Engineering & Mechanics Ningbo University Zhejiang Ningbo315211 China Ningbo Institute of Materials Technology and Engineering The Chinese Academy of Sciences Zhejiang Ningbo315201 China University of Chinese Academy of Sciences Beijing100049 China Faculty of Electrical Engineering and Computer Science Ningbo University Zhejiang315000 China

ISBN: (纸本)9781510683228

Nickel-based superalloys are widely used in aviation, aerospace, energy, petrochemical and other industrial fields due to their excellent high temperature strength, oxidation and corrosion resistance, excellent creep and fatigue resistance. However, there are many problems in the traditional processing methods, such as tool wear, thermal/mechanical damage of materials and so on. These problems limit the processing ability of micro structures and complex surfaces, making it difficult to process nickel-based superalloy components with high quality. Laser processing has the advantages of high precision, non-contact and green, which has become an effective means of nickel-based superalloy surface processing. In this paper, a new process of rotational multi-beam coupled nanosecond laser processing was used to study the groove cutting of nickel-based superalloy with variable defocus amount. The morphology and structure of the groove were observed and analyzed by laser confocal microscope and scanning electron microscope. The results show that the groove width is the smallest and the groove depth is larger when the defocus amount is -1.0 mm, and the laser energy density is larger when the defocus amount is close to -1.0 mm, and a relatively high adhesion layer is formed between the groove edge and the unmachined surface. By analyzing the groove straightness under different defocus amounts, the groove straightness first decreases and then increases, and the straightness is the smallest at -1.0 mm, indicating that -1.0 mm defocus position is a relatively suitable processing position. The research work can provide process guidance for the laser processing application of nickel-based superalloys. © 2024 SPIE.

关键词： High temperature corrosion

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Dynamic Flex-and-Flip Manipulation of Deformable Linear Objects

arXiv

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arXiv 2023年

作者： Jiang, Chunli Nazir, Abdullah Abbasnejad, Ghasem Seo, Jungwon The Hong Kong University of Science and Technology Clear Water Bay Hong Kong Department of Mechanical and Aerospace Engineering Department of Electronic and Computer Engineering Departments of Mechanical and Aerospace/-Electronic and Computer Engineering

This paper presents the technique of flex-and-flip manipulation. It is suitable for grasping thin, flexible linear objects lying on a flat surface. During the manipulation process, the object is first flexed by a robotic gripper whose fingers are placed on top of it, and later the increased internal energy of the object helps the gripper obtain a stable pinch grasp while the object flips into the space between the fingers. The dynamic interaction between the flexible object and the gripper is elaborated by analyzing how energy is exchanged. We also discuss the condition on friction to prevent loss of contact. Our flex-and-flip manipulation technique can be implemented with open-loop control and lends itself to underactuated, compliant finger mechanism. A set of experiments in robotic page turning performed with our customized hardware and software system demonstrates the effectiveness and robustness of the manipulation technique. Copyright © 2023, The Authors. All rights reserved.

关键词： Grippers

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Flexible Localization Method with Motion Estimation for Underwater Wireless Sensor Networks 26

Flexible Localization Method with Motion Estimation for Unde...

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26th International Conference on Advanced Communications Technology, ICACT 2024

作者： Ismail, A.S. Hawbani, Ammar Wang, Xingfu Aziz, Samah Abdel Zhao, Liang Saeed, Nasir School of Computer Science and Technology University of Science and Technology of China Anhui Hefei230027 China Zagazig University Faculty of Science Zagazig44519 Egypt School of Computer Science Shenyang Aerospace University Shenyang110136 China United Arab Emirates University Department of Electrical and Communication Engineering Al Ain15551 United Arab Emirates

ISBN: (纸本)9791188428120

Due to the challenging conditions of underwater environments, such as node mobility and large-scale networks, achieving localization in large-scale mobile underwater sensor networks (UWSN) is a difficult task. This paper introduces a scheme known as the Flexible Localization Method with Mobility Estimation (FLMME) for UWSNs by utilizing the expected mobility patterns of underwater objects. FLMME performs localization hierarchically by splitting the process into anchor and ordinary node localization. Each node estimates its next mobility pattern based on previous location information, enabling estimates about its next location. Anchor nodes, holding known locations, manage the localization process to balance accuracy and error trade-offs. Extensive simulations demonstrate that FLMME reduces localization errors and hence increases localization accuracy. © 2024 Global IT Research Institute - GIRI.

关键词： Location

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