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An efficient decoupling dynamic algorithm for coupled multi-spring-systems

COMPUTERS & STRUCTURES 2018年 209卷 44-56页

作者： Yuan, Peng Li, Dejian Cai, C. S. Xu, Guoji Cent S Univ Sch Civil Engn Changsha 410075 Hunan Peoples R China Louisiana State Univ Dept Civil & Environm Engn Baton Rouge LA 70803 USA Univ Notre Dame NatHaz Modeling Lab Notre Dame IN 46556 USA

In this paper, a novel explicit method for decoupling coupled multi-spring systems in the structural dynamic analysis is proposed by ensuring the second-order accuracy in the low-frequency domain. Two parameters mu and beta are introduced in this method to flexibly adjust the stability and accuracy properties and suppress the high-frequency spurious vibrations in the solution. Firstly, the standard formulations of this method are derived and its stability and accuracy are analyzed through comparisons with other available state-of-the-art explicit methods in the literature. Then, the performance of this proposed method is specifically evaluated in terms of accuracy, dissipation in the high-frequency domain and computational efficiency, and effectiveness in dealing with nonlinearity through three examples. Finally, a vertical coupled multi-spring system, a train-rail-sleeper-ballast-bridge system, is employed to demonstrate the efficiency and decoupling properties of the proposed method. The presented attractive performance of this method illustrates its advantages in engineering applications. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： decoupling algorithm Explicit method Stability limit Numerical dissipation Local truncation error Coupled structural systems

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Design and calibration of spoke piezoelectric six-dimensional force/torque sensor for space manipulator

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Chinese Journal of Aeronautics 2024年第1期37卷 218-235页

作者： Yingjun LI Guicong WANG Shuai ZHANG Yuanqin ZHOU Hongyu LI Zhenguang QI School of Mechanical Engineering University of JinanJinan 250022China

The large manipulator outside the space cabin is a multi-degree of freedom actuator for space *** order to realize the automatic control and flexible operation of the space manipulator,a novel spoke structure piezoelectric six-dimensional force/torque sensor with redundancy ability,high stiffness and good decoupling performance is innovatively *** on the deformation coordination relationship,the redundancy measurement mechanism is *** mathematical models of the sensor with and without branch fault are established *** finite element model is established to verify the feasibility of structure and redundancy measuring principle of the *** on the theoretical analysis and simulation analysis,the prototype of the sensor is *** and dynamic calibration experiments are carried *** actual output voltage signal of the six-dimensional force/torque sensor is collected to establish the equation between the standard input applied load and the actual output voltage *** on ant colony optimized BP algorithm,performance indexes of the sensor with and without branch fault are analyzed *** experimental results show that the spoke piezoelectric sixdimensional force/torque sensor with the eight-point support structure has good accuracy and ***,it has strong decoupling characteristic that can effectively shield the coupling between *** nonlinear errors and maximum interference errors of decoupled data with and without branch faults are less than 1% and 2%,*** natural frequency of the sixdimensional force sensor can reach 2856.45 Hz and has good dynamic *** research content lays a theoretical and experimental foundation for the design,development and application of the new six-dimensional force/torque sensors with ***,it will significantly improve the research level in this field,and provide a strong guarantee for the smoot

关键词： decoupling algorithm Piezoelectric Redundancy Six-dimensional force/torque sensor Space manipulator

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Cooperative control of multiple magnetically controlled soft robots

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INFORMATION SCIENCES 2024年 677卷

作者： Zhang, Pan Qing, Wenjie Lai, Xuzhi Wang, Yawu Wu, Min China Univ Geosci Sch Automat Wuhan 430074 Peoples R China Hubei Key Lab Adv Control & Intelligent Automat Co Wuhan 430074 Peoples R China Minist Educ Engn Res Ctr Intelligent Technol Geoexplorat Wuhan 430074 Peoples R China

Multiple magnetically controlled soft robots are more efficient in terms of task execution. However, how to realize such multiple robots moving along the respective different paths is still a challenge since they are in one driving magnetic field. In order to deal with this problem, this paper proposes a cooperative control method by fusing their parallel cooperative motion (multiple robots moving simultaneously) and their independent cooperative motion (single robot moving). Yet, there are two strong couplings in the fusion of such two cooperative motions, which makes the control more difficult. Thus, an enumeration-based decoupling algorithm is developed for the first combined mode coupling, and the speed of each robot is planned for the second motion speed coupling. Then, a neural network-based controller is developed to achieve the respective speed control simultaneously of multiple robots, and the deviation limiting controller is constructed to compensate the deviation angle. Finally, through the actual experiments, it is verified that the proposed method realizes effectively the motion of two robots along different paths and the mean absolute error of speed is about 0.1091 mm/s and 0.2118 mm/s, while the mean absolute error of tracking is about 0.3369 mm and 0.4454 mm, respectively.

关键词： Multiple magnetically controlled soft robots Cooperative control decoupling algorithm Neural network Deviation limiting controller

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A Modular Miniature 6-D Force Sensor Designed for Minimally Invasive Surgery

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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2024年 73卷

作者： Pan, Qiqi Luo, Jingjing Chen, Li Xue, Haodan Wang, Hongbo Fudan Univ Acad Engn & Technol Shanghai 200433 Peoples R China Shanghai Intelligent Robot Engn Technol Res Ctr Shanghai 200433 Peoples R China Minist Educ Intelligent Robot Engn Res Ctr Shanghai 200433 Peoples R China Shanghai Clin Res Ctr Aging & Med Shanghai 200040 Peoples R China

Force sensing is important in robot-assisted minimally invasive surgery (MIS), but it is still difficult to achieve both miniaturization and multidimensional perception at the same time. A modular design scheme of a miniature 6-D force sensor that can be integrated into an MIS robot is proposed. The force and moment applied on the sensor are converted into the signal response of the pressure-sensitive element, and the position of the pressure-sensitive element is located using flexible printed circuit board (FPCB), with which the wiring of signal circuits is simplified. The blind signal separation fast independent component analysis (FastICA) algorithm is used to decouple the output signal. The calibration experiment of the proposed sensor was carried out, and the calibration matrix was established. From the comparative experiment with commercial sensors, the accuracy, linearity, hysteresis, coupling error, and other performance of the proposed sensor are verified. The maximum coupling error is 2.8%, and the maximum stable measuring error is 3.9%. Analysis and experiments proved the rationality and scientificity of the sensor. This work opens up new ideas for the miniaturization, modularization, and integration of sensors for surgical robots.

关键词： 6-D force sensor decoupling algorithm miniature sensor 6-D force sensor decoupling algorithm miniature sensor

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A STUDY OF NUMERICAL POLLUTION OF THE DECOUPLED algorithm FOR THE CONVECTION MODEL IN SUPERPOSED FLUID AND POROUS LAYERS

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SIAM JOURNAL ON NUMERICAL ANALYSIS 2023年第2期61卷 1018-1056页

作者： Zhang, Yuhong Rong, Yao Zheng, Haibiao Hunan Normal Univ Coll Math & Comp Sci Changsha 410081 Hunan Peoples R China Shenzhen Technol Univ Ctr Adv Mat Diagnost Technol Shenzhen Key Lab Ultraintense Laser & Adv Mat Tech Shenzhen 518118 Guangdong Peoples R China Shenzhen Technol Univ Coll Engn Phys Shenzhen 518118 Guangdong Peoples R China East China Normal Univ Sch Math Sci Shanghai Key Lab Pure Math & Math Practice Shanghai Peoples R China

For coupling problems such as the Navier--Stokes--Darcy problem in porous and fluid layers, a natural question is that, while the orders of polynomials approximating the variables are different, could the lower order elements pollute the higher ones? In this paper, the numerical pol-lution of a decoupled algorithm for the unsteady convection model in superposed fluid and porous layers is studied. We first prove the existence and uniqueness of the weak solution to the convec-tion model with Beavers--Joseph--Saffman interface conditions, by using vanishing viscosity methods together with backward-Euler time discretization. Second, an efficient decoupled algorithm of the model based on the Lagrange multiplier method is proposed, and its stability is proved under some restrictions on coefficients and initial values. Then the optimal error estimates are provided reveal-ing that the optimal convergence orders can be achieved without using equal or similar order finite elements for the fluid velocities in fluid and porous layers. This means that there is no numerical pollution between lower and higher order elements when the matched finite element pairs are used. Finally, numerical tests are implemented to verify our theoretical results.

关键词： numerical pollution unsteady convection model decoupling algorithm optimal error estimates

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decoupling time filter method for the non-stationary Navier-Stokes/Darcy model

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MATHEMATICAL METHODS IN THE APPLIED SCIENCES 2023年第3期46卷 3294-3305页

作者： Tang, Zhuyan Jia, Xiaofeng Feng, Hui Wuhan Univ Sch Math & Stat Wuhan 430072 Peoples R China Wuhan Univ Hubei Key Lab Computat Sci Wuhan 430072 Peoples R China

In this paper, we propose time filter algorithm based on the Backward Euler method for the non-stationary Navier-Stokes/Darcy problems. The decoupling method is composed of Backward Euler method and normal time filter. Stability and the second-order convergence are also proved in details. Finally, numerical examples are listed to validate the theoretical analysis.

关键词： decoupling algorithm Navier-Stokes Darcy model second-order convergence time filter method

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Time-Variant Reliability Optimization for Stress Balance in Press-Pack Insulated Gate Bipolar Transistors

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IEEE ACCESS 2023年 11卷 98059-98069页

作者： Li, Hangyang Yang, Tongguang Liu, Xinglin Zhong, Jingyi Mo, Jiaxin Zhou, Han Xiao, Zhongkun Hunan City Univ Hunan Prov Key Lab Energy Monitoring & Edge Comp S Yiyang 413000 Peoples R China

Stress imbalance significantly affects the performance of a press-pack insulated gate bipolar transistor (IGBT). Time-variant loads and conditions lead to the stress fluctuations, exacerbating the impacts. The conventional reliability optimization faces efficiency barriers due to the nested time-variant reliability analysis and design optimization. In this paper, a time-variant reliability optimization approach for press-pack IGBTs is proposed to address the efficiency issue of the IGBT reliability optimization. The performance functions of the maximum and typical stresses are formulated as the optimization objective and constraint. A time-variant reliability optimization model is formulated considering the stress balance reliability degradation within the service cycle. A decoupling algorithm is proposed to transform the nested optimization into a sequential iteration of static reliability optimization and time-variant reliability analysis. The reliability analysis utilizes the performance function continuity in the time domain to reduce the evaluations for the most likelihood points, thereby enhancing efficiency. Numerical and experimental results on an actual IGBT demonstrate the accuracy of the stress balance performance analysis. The time-variant reliability optimization based on the performance functions improves the stress balance performance by 16.3% and meets the reliability requirements within the service cycle. Compared with the conventional double-loop approach, the difference between the solution of the proposed approach with the reference solution is 0.4%, and the efficiency is 334 times that of the double-loop approach. The performance advantages in accuracy and efficiency exhibit the application potential of this approach.

关键词： Insulated gate bipolar transistors Reliability Stress Optimization Power system reliability Uncertainty Stochastic processes decoupling algorithm insulated gate bipolar transistor stress balance time-variant reliability optimization

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Modular Torque Control of Multi-Three-Phase Synchronous Motor Drives

Modular Torque Control of Multi-Three-Phase Synchronous Moto...

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2023 IEEE Energy Conversion Congress and Exposition, ECCE 2023

作者： Tolosano, Luisa Armando, Eric Rubino, Sandro Mandrile, Fabio Bojoi, Radu Politecnico di Torino Dipartimento Energia 'G. Ferraris' Torino10129 Italy

ISBN: (纸本)9798350316445

Multiphase motors offer more degrees of freedom when compared to their three-phase counterparts. Their intrinsic redundant structure enables the post-fault operation of the drive, thus preventing inoperability. Additionally, more advantages are obtained when a modular drive topology is adopted in machine windings and power converters. This is particularly convenient, especially when three-phase technology can be adopted, resulting in a multi-three-phase drive configuration. However, modular torque control strategies are needed to fully exploit the advantages provided by the multi-three-phase configuration. Therefore, an innovative control scheme implementing modular torque regulation of multi three-phase synchronous motor is proposed in this paper. The stator flux amplitude and the torque-producing current component corresponding to each three-phase set are independently controlled to perform the decoupled torque regulation. Experimental results on a 60 kW quadruple three-phase interior permanent magnet (IPM) synchronous motor are provided to prove the effectiveness of the proposed torque control solution. © 2023 IEEE.

关键词： decoupling algorithm modular control multi three-phase synchronous motors multiphase electrical drives

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A decoupling approach for time-dependent robust optimization with application to power semiconductor devices

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APPLIED MATHEMATICAL MODELLING 2021年 99卷 129-146页

作者： Huang, Zhiliang Guo, Xiaohui Yang, Tongguang Lei, Shuwen Zhao, Zhiguo Hunan City Univ Key Lab Energy Monitoring & Edge Comp Smart City Yiyang 413002 Peoples R China Hunan Haicheng Yuxin Informat Technol Co Ltd Changsha 410141 Hunan Peoples R China

In this paper, a time-dependent robust optimization model is proposed by introducing a concept of expected interval quality loss as the robustness metric. The purpose is to provide a potential analysis tool for power semiconductor devices involving stochastic processes. Unlike conventional robustness indicators, the metric is formulated by calculating the expectation and variation of the maximal instantaneous quality loss and capturing the auto-correlation of the quality loss over the time interval. In terms of model solving, the time-dependent robust optimization involves a nested optimization, namely the outer design optimization requires to call the inner robustness analysis frequently. It will lead to extremely low computational efficiency. For reducing robustness evaluations, a decoupling framework is proposed to convert the nested optimization into a sequential iterative process of design optimization and time-dependent robustness analysis. For further improving the efficiency of each robustness analysis, a semi-second-order approximation of quality characteristics is created based on the information at the previous iteration. Two engineering applications of power semiconductor devices verify the validity and feasibility of the proposed approach. (c) 2021 Elsevier Inc. All rights reserved.

关键词： Time-dependent problem Quality loss function Robust design optimization decoupling algorithm Power semiconductor device

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A TIME-FRACTIONAL MEAN-FIELD CONTROL MODELING SUBDIFFUSIVE ADVECTIVE TRANSPORT

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SIAM JOURNAL ON SCIENTIFIC COMPUTING 2023年第6期45卷 B884-B905页

作者： Zheng, Xiangcheng Yang, Zhiwei Li, Wuchen Wang, Hong Shandong Univ Sch Math Jinan 250100 Peoples R China Fudan Univ Sch Math Sci Res Inst Intelligent Complex Syst Shanghai 200433 Peoples R China Univ South Carolina Dept Math Columbia SC 29208 USA

A time-fractional mean-field control (MFC) is developed for a prototype model of accidental spill of a hazardous contaminant in subsurface porous media, which is a representative and recurrent environmental threat to the public, to optimize the flow pattern so that the spilled contaminant is remediated with the minimal cost required to ensure the clean water supply. A strongly coupled nonlinear system of a multiple time-scale time-fractional transport equation and a backward multiple time-scale time-fractional Hamilton-Jacobi equation is derived using the first-order optimality condition. A sequentially decoupled time-stepping finite element method is derived for the numerical simulation of the MFC. Numerical experiments are presented to investigate the performance of the MFC, which show that the MFC determines an optimal flow pattern to ensure clean groundwater supply during and beyond the time period of contaminant spill with minimal cost.

关键词： mean field control time-fractional subdiffusive advective transport Hamilton-Jacobi equation decoupling algorithm

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