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A Soft Robotic Fish with Variable-stiffness decoupled Mechanisms

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Journal of Bionic Engineering 2018年第4期15卷 599-609页

作者： Kangkang Li Hongzhou Jiang Siyu Wang Jianmin Yu School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

A Body and/or Caudal Fin （BCF） fish modulate its body stiffness by mechanisms consisting of antagonistic muscles. The mecha- nisms can be considered as Redundant Planar Rotational Parallel Mechanisms （RPRPM） with antagonistic flexible elements. For a typical RPRPM, its stiffness consists of the adjustable stiffness resulting from internal forces and the inherent stiffness caused by inherent com- pliances of flexible elements. In order to decouple the adjustable stiffness from the inherent stiffness and expand the range of stiffness variation, a variable-stiffness decoupled mechanism based on the Mechanically Adjustable Compliance and Controllable Equilibrium Position Actuator （MACCEPA） is presented and used to construct a soft robotic fish with large stiffness variation. According to the analysis of the evolution from RPRPM to MACCEPA, it can be found that MACCEPA is just a special type of RPRPM with only an adjustable stiffness. In addition, MACCEPA existed before RPRPM mechanism. The prototype of the soft robotic fish with variable- stiffness decoupled mechanisms is built to explore the relationships between the body stiffness and the swimming performance. It is validated experimentally that the stiffness variation multiple of the robotic fish is raised, the swimming performance of the robotic fish is improved when the stiffness is modulated to match the driving frequency.

关键词： bionic soft robotic fish variable stiffness decoupled MACCEPA pretension

A sparse recovery model with fast decoupled solution for distribution state estimation and its performance analysis

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Journal of Modern Power Systems and Clean Energy 2019年第6期7卷 1411-1421页

作者： Junwei YANG Wenchuan WU Weiye ZHENG Yuntao JU Department of Electrical Engineering Tsinghua UniversityBeijing 100084China Department of Electrical and Electronic Engineering The University of Hong KongHong KongChina College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China

This paper introduces a robust sparse recovery model for compressing bad data and state estimation(SE),based on a revised multi-stage convex relaxation(R-Capped-L1)model.To improve the calculation efficiency,a fast decoupled solution is adopted.The proposed method can be used for three-phase unbalanced distribution networks with both phasor measurement unit and remote terminal unit measurements.The robustness and the computational efficiency of the R-Capped-Ll model with fast decoupled solution are compared with some popular SE methods by numerical tests on several three-phase distribution networks.

关键词： Distribution system State estimation Sparse recovery Fast decoupled method

decoupled MODEL FOR FLATNESS CONTROL IN 4-H CVC COLD ROLLING MILLS

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中国有色金属学会会刊：英文版 1998年第4期8卷 185-187页

作者： Zhong Jue and Chen Jie College of Mechanical and Electrical Engineering, Central South University of Technology, Changsha 410083, P. R. China

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关键词： decoupled model gage and shape control cold rolling

Highly efficient and unconditionally energy stable semi-discrete time-marching numerical scheme for the two-phase incompressible flow phase-field system with variable-density and viscosity

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Science China Mathematics 2022年第12期65卷 2631-2656页

作者： Chuanjun Chen Xiaofeng Yang School of Mathematics and Information Sciences Yantai UniversityYantai 264005China Department of Mathematics University of South CarolinaSC29208USA

For the variable-density/viscosity Cahn-Hilliard phase-field model of the binary-phase incompressible fluid flow system, the development of easy-to-implement numerical schemes has long been known as a challenging problem. We develop a novel fully-decoupled numerical technique in this article which can achieve unconditional energy stability while explicitly discretizing nonlinear coupling items. The idea is invented on the basis of combining the Strang operator splitting method and the novel decoupling method by using the zero-energy-contribution property. The scheme only needs to solve a series of completely independent linear elliptic equations at each time step, in which the Cahn-Hilliard equation and the pressure Poisson equation are with constant coefficients. To demonstrate the effectiveness of the scheme, we provide the rigorous proof of the energy stability/solvability, and also perform ample accuracy and stability tests and 2D/3D numerical simulations, including the Rayleigh-Taylor instability and bubble rising dynamics.

关键词： variable-density decoupled time marching Cahn-Hilliard equation Navier-Stokes equations energy stability

Expansion of the decoupled Discreet-Time Jacobian Eigenvalue Approximation for Model-Free Analysis of PMU Data

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Journal of Power and Energy Engineering 2017年第6期5卷 14-35页

作者： Sean D. Kantra Elham B. Makram Holcombe Department of Electrical and Computer Engineering Clemson University Clemson USA

This paper proposes an extension of the algorithm in [1], as well as utilization of the wavelet transform in event detection, including High Impedance Fault (HIF). Techniques to analyze the abundant data of PMUs quickly and effectively are paramount to increasing response time to events and unstable parameters. With the amount of data PMUs output, unstable parameters, tie line oscillations, and HIFs are often overlooked in the bulk of the data. This paper explores model-free techniques to attain stability information and determine events in real-time. When full system connectivity is unknown, many traditional methods requiring other bus measurements can be impossible or computationally extensive to apply. The traditional method of interest is analyzing the power flow Jacobian for singularities and system weak points, attained by applying singular value decomposition. This paper further develops upon the approach in [1] to expand the Discrete-Time Jacobian Eigenvalue Approximation (DDJEA), giving values to significant off-diagonal terms while establishing a generalized connectivity between correlated buses. Statistical linear models are applied over large data sets to prove significance to each term. Then the off diagonal terms are given time-varying weights to account for changes in topology or sensitivity to events using a reduced system model. The results of this novel method are compared to the present errors of the previous publication in order to quantify the degree of improvement that this novel method imposes. The effective bus eigenvalues are briefly compared to Prony analysis to check similarities. An additional application for biorthogonal wavelets is also introduced to detect event types, including the HIF, for PMU data.

关键词： Synchrophasor PMU openPDC Power Flow Jacobian decoupled Discrete-Time Jacobian Approximation (DDJEA) Singular Value Decomposition (SVD) High Impedance Fault (HIF) Discrete Wavelet Transform (DWT)

Analysis of the Load Flow Problem in Power System Planning Studies

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Energy and Power Engineering 2015年第10期7卷 509-523页

作者： Olukayode A. Afolabi Warsame H. Ali Penrose Cofie John Fuller Pamela Obiomon Emmanuel S. Kolawole Department of Electrical and Computer Engineering Prairie View A&M University Prairie View USA

Load flow is an important tool used by power engineers for planning, to determine the best operation for a power system and exchange of power between utility companies. In order to have an efficient operating power system, it is necessary to determine which method is suitable and efficient for the system’s load flow analysis. A power flow analysis method may take a long time and therefore prevent achieving an accurate result to a power flow solution because of continuous changes in power demand and generations. This paper presents analysis of the load flow problem in power system planning studies. The numerical methods: Gauss-Seidel, Newton-Raphson and Fast decoupled methods were compared for a power flow analysis solution. Simulation is carried out using Matlab for test cases of IEEE 9-Bus, IEEE 30-Bus and IEEE 57-Bus system. The simulation results were compared for number of iteration, computational time, tolerance value and convergence. The compared results show that Newton-Raphson is the most reliable method because it has the least number of iteration and converges faster.

关键词： Load Flow Bus Gauss-Seidel Newton-Raphson Fast decoupled Voltage Magnitude Voltage Angle Active Power Reactive Power Iteration Convergence

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UKF训练RMLP网络的快速算法

信号处理 2006年第5期22卷 653-657页

作者：乔士东沈振康国防科学技术大学ATR实验室湖南长沙410073

UKF训练PMLP的优点是无需计算动态偏导数,但UKF面临计算量大的问题,降低计算量是UKF的研究重点之一。本文提出反向遍历sigma点的方法,可以显著降低UKF有2N_w+1或N_w+2个sigma点两种情况下的计算量。另外,对2N_w+1个sigma点的情况,本文... 详细信息

UKF训练PMLP的优点是无需计算动态偏导数,但UKF面临计算量大的问题,降低计算量是UKF的研究重点之一。本文提出反向遍历sigma点的方法,可以显著降低UKF有2N_w+1或N_w+2个sigma点两种情况下的计算量。另外,对2N_w+1个sigma点的情况,本文提出解耦合方法,能有效降低存储协方差阵所需空间。综合反向遍历方法和解耦合方法,本文给出UKF训练RMLP的快速算法。在动态系统辨识的仿真中,本文方法节省近80%的计算量和近90%的存储空间。

关键词： Unscented Kalman Filter(UKF) decoupled Extended Kalman Filter(DEKF) 反馈多层感知网络(RMLP) 动态系统辨识