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arXiv 2022年

作者： Sutrisno, Amanda Mathews, Chase Braun, David J. The Advanced Robotics and Control Laboratory within the Center for Rehabilitation Engineering and Assistive Technology Department of Mechanical Engineering Vanderbilt University NashvilleTN37235 United States

Springs store mechanical energy similar to batteries storing electrical energy. However, conventional springs are heavy and store limited amounts of mechanical energy relative to batteries, i.e they have low mass-energy-density. Next-generation 3D printing technology could potentially enable manufacturing low cost lightweight springs with high energy storage capacity. Here we present a novel design of a high-energy-density 3D printed torsional spiral spring using structural optimization. By optimizing the internal structure of the spring we obtained a 45% increase in the mass energy density, compared to a torsional spiral spring of uniform thickness. Our result suggests that optimally designed 3D printed springs could enable robots to recycle more mechanical energy per unit mass, potentially reducing the energy required to control robots. © 2022, CC BY-NC-ND.

关键词： Structural optimization

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Heterogeneous microstructure and mechanical behaviour of Al-8.3Fe-1.3V-1.8Si alloy produced by laser powder bed fusion

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Virtual and Physical Prototyping 2023年第1期18卷 Article: e2155197页

作者： Yu, S.J. Wang, P. Li, H.C. Setchi, R. Wu, M.W. Liu, Z.Y. Chen, Z.W. Waqar, S. Zhang, L.C. Additive Manufacturing Institute Shenzhen University Shenzhen China Guangdong Key Laboratory of Electromagnetic Control and Intelligent Robotics College of Mechatronics and Control Engineering Shenzhen University Shenzhen China School of Materials Science and Engineering Shanghai University of Engineering Science Shanghai China Cardiff School of Engineering Cardiff University Cardiff United Kingdom Department of Materials and Mineral Resources Engineering National Taipei University of Technology Taipei Taiwan Department of Mechanical Engineering Institute of Space Technology Islamabad Pakistan School of Engineering Edith Cowan University Perth Australia

The relationship between processing parameters, microstructure, and mechanical properties of Al-8.3Fe-1.3V-1.8Si alloy processed by laser powder bed fusion is seldom studied. Therefore, fully dense alloys with two parameters were selected to investigate this key issue. The results show that the alloy with low power and scanning speed (S200) shows fan-shell-shaped melt pools and laser tracks while another (S350) shows a deeper and wider melt pool. Both alloys obtain a heterogeneous microstructure without a secondary phase in melt pool (MP) and a nano-sized phase in melt pool boundary (MPB). The difference between solid-solution strengthening and Orowan strengthening in MP and MPB contributes to the difference in compressive yield strength (S200: 380 ± 14 MPa and S350: 705 ± 16 MPa), and heterogeneous nano-hardness results in different crack behaviours and failure strains. This work indicates that adjusting processing parameters is an effective method to control microstructure and mechanical properties of this alloy. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

关键词： Aluminum alloys

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Grating‐like anechoic layer for broadband underwater sound absorption

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International Journal of Mechanical System Dynamics 2022年第3期2卷 265-277页

作者： Chenlei Yu Mingyu Duan Wei He Xin Chen Fengxian Xin Tian J.Lu State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'anChina MOE Key Laboratory for Multifunctional Materials and Structures School of Aerospace EngineeringXi'an Jiaotong UniversityXi'anChina Department of Advanced Manufacturing and Robotics College of EngineeringPeking UniversityBeijingChina Xi'an Modern Chemistry Research Institute Xi'anChina State Key Laboratory for Mechanics and Control of Mechanical Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjingChina MIIT Key Laboratory of Multifunctional Lightweight Materials and Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjingChina

To address the challenging task of effective sound absorption in the low and broad frequency band for underwater structures,we propose a novel grating‐like anechoic layer by filling rubber blocks and an air backing layer into metallic *** metallic gratings are incorporated into the anechoic layer as a skeleton for enhanced viscoelastic dissipation by promoting shear deformation between rubber and metal *** introduction of an air backing layer releases the bottom constraint of the rubber,thus intensifying its deformation under acoustic *** on the homogenization method and the transfer matrix method,a theoretical model is developed to evaluate the sound absorption performance of the proposed anechoic layer,which is validated against finite element simulation *** is demonstrated that a sound absorption coefficient of the grating‐like anechoic layer of 0.8 can be achieved in the frequency range of 1294-10000 *** the importance of sound absorption at varying frequencies,the weighted average method is subsequently used to comprehensively evaluate the performance of the anechoic ***,with structural density taken into consideration,an integrated index is proposed to further evaluate the acoustic properties of the proposed anechoic ***,the backing conditions and the boundary conditions of finite‐size structures are *** results provide helpful theoretical guidance for designing novel acoustic metamaterials with broadband low‐frequency underwater sound absorption.

关键词： underwater sound absorption broadband transfer matrix method rubber coating

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Identification and control of Industrial Hydraulic Actuators with a Hammerstein-Wiener Model Approach 1st

Identification and Control of Industrial Hydraulic Actuators...

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1st International Symposium on Systems Modelling and Simulation, SMS 2024

作者： Mohamad Ali, Nur Husnina Jaafar, Hazriq Izzuan Ghazali, Rozaimi Ghani, Muhamad Fadli Soon, Chong Chee Has, Zulfatman Fakulti Teknologi dan Kejuruteraan Elektrik Universiti Teknikal Malaysia Melaka Melaka Malaysia Center for Robotics and Industrial Automation Universiti Teknikal Malaysia Melaka Melaka Malaysia Department of Control and Mechatronics Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia Johor Malaysia Penang Branch Campus Pulau Pinang Malaysia Electrical Engineering Department University of Muhammadiyah Malang Malang Indonesia

ISBN: (纸本)9789819646128

In motion control applications, the precise regulation of Industrial Hydraulic Actuators (IHA) is essential for properly ascertaining the position of the actuator rod. This research used a Hammerstein-Wiener (HW) model to characterize the system, integrating a dead zone to account for nonlinearities and using an open-loop methodology. A grey-box modelling technique is used for estimating the discrete-time model of the system and identifying its parameters. The System Identification toolbox in MATLAB functions as the principal instrument for model estimation, using input-output data acquired via experimental procedures. The validation of the input-output data demonstrated a promising best-fit percentage of 88.21%, indicating a robust connection between the HW model and the real system. To assess the trajectory tracking efficacy of the system, Proportional-Integral-Derivative (PID) and Fractional Order PID (FOPID) controllers developed and evaluated using both simulation and experimental data based on a multi-sinusoidal trajectory. The findings indicate that the FOPID controller surpasses the traditional PID controller, producing reduced Mean Square Error (MSE) and Root Mean Square Error (RMSE) values. In simulations, the FOPID control technique enhanced MSE by 32.8% and RMSE by 18.0% relative to the PID controller, although the experimental findings indicated improvements of 31.9% and 17.5%, respectively. The results highlight the superior efficacy of the FOPID controller in improving trajectory tracking performance owing to its greater complexity and flexibility. Future research may concentrate on developing more sophisticated controllers, including intelligent or nonlinear variants, to enhance the tracking precision of the IHA system. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2025.

关键词： Three term control systems

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Multiplier analysis of Lurye systems with power signals

Multiplier analysis of Lurye systems with power signals

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IEEE Conference on Decision and control

作者： William P. Heath Joaquin Carrasco School of Computer Science and Engineering Bangor University Dean St LL57 1UT UK Department of Electrical and Electronic Engineering Control Systems and Robotics Group Nancy Rothwell Building University of Manchester M13 9PL UK

ISBN: (数字)9798350316339

ISBN: (纸本)9798350316346

Multipliers can be used to guarantee both the Lyapunov stability and input-output stability of Lurye systems with time-invariant memoryless slope-restricted nonlinearities. If a dynamic multiplier is used there is no guarantee the closedloop system has finite incremental gain. It has been suggested in the literature that without this guarantee such a system may be critically sensitive to time-varying exogenous signals including noise. We show that multipliers guarantee the power gain of the system to be bounded and quantifiable. Furthermore power may be measured about an appropriate steady state bias term, provided the multiplier does not require the nonlinearity to be odd. Hence dynamic multipliers can be used to guarantee Lurye systems have low sensitivity to noise, provided other exogenous systems have constant steady state. We illustrate the analysis with an example where the exogenous signal is a power signal with non-zero mean.

关键词： Sensitivity Power measurement Noise Stability analysis Steady-state Time-varying systems Lyapunov methods

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A Machine Learning-Based Routing Technique for Off-chain Transactions in Payment Channel Networks 5

A Machine Learning-Based Routing Technique for Off-chain Tra...

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5th IEEE International Conference on Smart Internet of Things, SmartIoT 2021

作者： Kadry, Heba Gadallah, Yasser Robotics Control and Smart Systems Program American University in Cairo New Cairo11835 Egypt Department of Electronics and Communications Engineering American University in Cairo New Cairo11835 Egypt

ISBN: (纸本)9781665445115

Blockchain is a foundational technology that has the potential to create new prospects for our economic and social systems. However, the lack of scalability limits the capability to deliver a target throughput and latency compared to the traditional financial systems. Layer-two is a collective term for solutions designed to enhance scalability by handling transactions off the main chain. For example, bidirectional payment channels allow the execution of fast transactions between two parties, thus forming the so-called payment channel networks (PCNs). Therefore, efficient routing protocols are needed to find a payment path from the sender to the receiver, with the lowest transaction fees. These protocols have to consider, among other factors, the unexpected online/offline behavior of the constituent payment nodes and the payment channel imbalance. This study proposes a novel machine learning-based technique for off-chain transaction routing. It is a fully distributed approach to be used within PCNs. For this purpose, the effect of the offline nodes and channel imbalance on the payment channels network are modeled. The simulation results demonstrate that the proposed technique strikes a good balance when considering the success ratio, transaction fees, routing efficiency, transaction overhead, and transaction maintenance overhead compared to other techniques that have previously been proposed for the same purpose. © 2021 IEEE.

关键词： Scalability

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Safe Navigation and Obstacle Avoidance Using Differentiable Optimization Based control Barrier Functions

arXiv

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arXiv 2023年

作者： Dai, Bolun Khorrambakht, Rooholla Krishnamurthy, Prashanth Gonçalves, Vinícius Tzes, Anthony Khorrami, Farshad Control/Robotics Research Laboratory Electrical & Computer Engineering Department Tandon School of Engineering New York University BrooklynNY11201 United States Electrical Engineering New York University Abu Dhabi Abu Dhabi129188 United Arab Emirates

control barrier functions (CBFs) have been widely applied to safety-critical robotic applications. However, the construction of control barrier functions for robotic systems remains a challenging task. Recently, collision detection using differentiable optimization has provided a way to compute the minimum uniform scaling factor that results in an intersection between two convex shapes and to also compute the Jacobian of the scaling factor. In this paper, we propose a framework that uses this scaling factor, with an offset, to systematically define a CBF for obstacle avoidance tasks. We provide theoretical analyses of the continuity and continuous differentiability of the proposed CBF. We empirically evaluate the proposed CBF's behavior and show that the resulting optimal control problem is computationally efficient, which makes it applicable for realtime robotic control. We validate our approach, first using a 2D mobile robot example, then on the Franka-Emika Research 3 (FR3) robot manipulator both in simulation and experiment. Index Terms-Robot safety, collision avoidance. © 2023, CC BY.

关键词： Robot applications

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Graph-Based Visual-Kinematic Fusion and Monte Carlo Initialization for Fast-Deployable Cable-Driven Robots

Graph-Based Visual-Kinematic Fusion and Monte Carlo Initiali...

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

作者： R. Khorrambakht H. Damirchi M.R. Dindarloo A. Saki S.A. Khalilpour Hamid D. Taghirad Stephan Weiss Electrical & Computer Engineering Department Control/Robotics Research Laboratory Tandon School of Engineering New York University Brooklyn NY School of Computer Science University of Adelaide Australia Faculty of Electrical Engineering University of Technology Tehran Iran Department of Smart Systems Technologies University of Klagenfurt Austria

Ease of calibration and high-accuracy task-space state-estimation purely based on onboard sensors is a key requirement for enabling easily deployable cable robots in real-world applications. In this work, we incorporate the onboard camera and kinematic sensors to drive a statistical fusion framework that presents a unified localization and calibration system which requires no initial values for the kinematic parameters. This is achieved by formulating a Monte-Carlo algorithm that initializes a factor-graph representation of the calibration and localization problem. With this, we are able to jointly identify both the kinematic parameters and the visual odometry scale alongside their corresponding uncertainties. We demonstrate the practical applicability of the framework using our state-estimation dataset recorded with the ARAS-CAM suspended cable driven parallel robot, and published as part of this manuscript.

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Feature Extraction of Motor Imagination EEG Signals for a Collaborative Exoskeleton Robot Based on PSD Analysis

Feature Extraction of Motor Imagination EEG Signals for a Co...

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Chinese control Conference (CCC)

作者： Yunfeng Wu Junze Li Zichen Ren Bo Lu Changzhu Zhang Peng Qi Department of Control Science and Engineering Tongji University Shanghai China Elmore Family School of Electrical and Computer Engineering Purdue University West Lafayette Indiana United States Robotics and Microsystems Center School of Mechanicaland Electric Engineering Soochow University Suzhou China

The integration of brain-machine interface and exoskeleton robot has been widespread application in gait correction, walking assistance, and numerous other scenarios. To effectively extract the electroencephalogram (EEG) signal features of motor imagery while wearing an exoskeleton, this study proposes a frequency band pre-determination method based on power spectral density (PSD) that enables common spatial patterns (CSP) to extract features from the frequency band with the highest energy in the EEG. The signal power spectral density of all channels is obtained at or near the average frequency of the maximum short interval frequency component energy. A second round of filtering is performed on the data, and the signal components are used as input for the subsequent feature extraction step. The CSP method extracts features from the spatial domain signal and generates feature maps. Finally, Support Vector Machines (SVM) are utilized to classify the EEG signals. Based on the pre-set gait of the exoskeleton robot and the motor imagery paradigm, feature extraction and classification of motor imagery EEG data during exoskeleton use were conducted, with an average accuracy rate of 77%. The experimental results demonstrate the effectiveness of this method in extracting the motor imagery EEG features during exoskeleton use.

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Development of an Automated Wheelchair for Visually Impaired People 23

Development of an Automated Wheelchair for Visually Impaired...

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23rd IEEE International Multi-Topic Conference, INMIC 2020

作者： Siddiqui, Arslan Anwer, Talha Zafar, Saqib Maqbool, Hafiz Farhan Siddiqi, Dilruba Ahmad, Nasir Mehmood, Muhammad Armghan Riaz, Ahsan University of Engineering and Technology Department of Mechatronics and Control Engineering Lahore Pakistan Human Centered Robotics Lab National Center of Robotics and Automation Lahore Pakistan

ISBN: (纸本)9781728198934

This paper presents the development of an automated wheelchair, a mobility-assistive device that helps visually impaired people in the community. For such people, there are many constraints associated while moving to their desired destination. One of the main objectives of the current work is to design and develop a low-cost smart wheelchair that navigates to its destination autonomously. This smart navigation system (SNS) uses a machine vision technique for localization and path planning and proximity sensors for obstacle avoidance. The wheelchair can autonomously navigate to the location selected by the user through a braille keypad interface. The mechanical design is focused to make a finished product that is stable and according to basic medical considerations. The hardware design in the paper aims to enable a visually impaired person to perform daily routine tasks without the need for any assistance. © 2020 IEEE.

关键词： Computer vision

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