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Multibody dynamics in computational mechanics and engineering applications

COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2006年第41-43期195卷 5509-5522页

作者： Schiehlen, Werner Guse, Nils Seifried, Robert Univ Stuttgart Inst Engn & Computat Mech D-70550 Stuttgart Germany

Multibody dynamics is based on analytical mechanics and its engineering applications including automobiles, railways, rotating machinery, walking machines and prostheses. Multibody dynamics is closely related to control design and computer methods. Recent developments in multibody dynamics are identified as elastic or flexible systems, respectively, contact and impact problems, and actively controlled systems. Recent activities in multibody dynamics, recursive algorithms and methods for dynamical analysis are presented. Engineering systems are treated by linear matrix methods, nonlinear dynamics approaches and simulation techniques. In more detail applications are shown from efficiently control mechanisms and structural vibrations due to impacts with plastic deformation. (c) 2005 Elsevier B.V. All rights reserved.

关键词： multibody system dynamics recursive algorithms controlled mechanisms plastic impacts

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Mechanical response of linear viscoelastic composite laminates incorporating non-isothermal physical aging effects

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COMPOSITES SCIENCE AND TECHNOLOGY 1999年第9期59卷 1411-1427页

作者： Bradshaw, RD Brinson, LC Northwestern Univ Dept Engn Mech Evanston IL 60208 USA

This paper presents a method of predicting the mechanical response of composite laminates including the effects of linear viscoelasticity and physical aging. Effective-time theory has been used to characterize the physical aging behavior of each linear viscoelastic lamina. In accordance with experimental findings, the aging behavior of each lamina is allowed to differ in the shear and transverse directions. The mechanical loading is restricted to the linear range, which decouples the aging and load behavior. A recursive algorithm has been used to solve the hereditary convolution integral that governs the response of each ply. Classical thin-laminate theory is then used to assemble the individual ply response equations and determine the overall laminate response to general in-plane force and moment loading. The method automatically recovers the ply-level stresses and strains, which are often critical to strength and durability predictions. The model can use either lamina compliance or modulus properties as its basis. Several illustrative examples of long-term laminate response to variable loading are presented and the impact of physical aging is explored. It is shown that for multidirectional laminates, the stiffness of the lamina in the fiber directions can allow simplifications of the model. (C) 1999 Elsevier Science Ltd. All rights reserved.

关键词：复合材料力学性能线性粘弹性老化 LAMINATE recursive algorithms physical linear viscoelasticity ageing behavior ageing effects Aging composite laminates

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New model for system behavior prediction based on belief rule based systems

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INFORMATION SCIENCES 2010年第24期180卷 4834-4864页

作者： Zhou, Zhi-Jie Hu, Chang-Hua Xu, Dong-Ling Yang, Jian-Bo Zhou, Dong-Hua Tsinghua Univ Dept Automat TNList Beijing 100084 Peoples R China High Tech Inst Xian Xian 710025 Shaanxi Peoples R China Univ Manchester Manchester Business Sch Manchester M15 6PB Lancs England

To predict the behavior of a complex engineering system, a model can be built and trained using historical data. However, it may be difficult to obtain a complete and accurate set of data to train the model. Consequently, the model may be incapable of predicting the future behavior of the system with reasonable accuracy. On the other hand, expert knowledge of a qualitative nature and partial historical information about system behavior may be available which can be converted into a belief rule base (BRB). Based on the unique features of BRB, this paper is devoted to overcoming the above mentioned difficulty by developing a forecasting model composed of two BRBs and two recursive learning algorithms, which operate together in an integrated manner. An initially constructed forecasting model has some unknown parameters which may be manually tuned and then trained or updated using the learning algorithms once data become available. Based on expert intervention which can reflect system operation patterns, two algorithms are developed on the basis of the evidential reasoning (ER) algorithm and the recursive expectation maximization (EM) algorithm with the former used for handling judgmental outputs and the latter for processing numerical outputs, respectively. Using the proposed algorithms, the training of the forecasting model can be started as soon as there are some data available, without having to wait until a complete set of data are all collected, which is critical when the forecasting model needs to be updated in real-time within a given time limit. A numerical simulation study shows that under expert intervention, the forecasting model is flexible, can be automatically tuned to predict the behavior of a complicated system, and may be applied widely in engineering. It is demonstrated that if certain conditions are met, the proposed recursive algorithms can converge to a local optimum. A case study is also conducted to show the wide potential applications of the for

关键词： Belief rule base Forecasting Uncertainty Evidential reasoning recursive algorithms

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Simulation-based actuator selection for redundantly actuated robot mechanisms

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JOURNAL OF ROBOTIC SYSTEMS 2002年第8期19卷 379-390页

作者： Lee, YH Han, YM Iurascu, CC Park, FC Seoul Natl Univ Sch Mech & Aerosp Engn Seoul 151742 South Korea

This article presents a simulation-based strategy for sizing the actuators of a redundantly actuated robotic mechanism. The class of robotic mechanisms we consider may contain one or more closed loops and possess an arbitrary number of active and passive joints, and the number of actuators may exceed the mechanism's kinematic degrees of freedom. Our approach relies on a series of dynamic simulations of the mechanism, by applying Taguchi's method to systematically perform the simulations. To efficiently perform each of the dynamic simulations, we develop, using tools from modern screw theory, new recursive algorithms for the forward and inverse dynamics of the class of redundantly actuated mechanisms described. (C) 2002 Wiley Periodicals, Inc.

关键词： actuators recursive algorithms inverse kinematics CLOSED LOOP TOOL USE Degree of freedom Robot Dynamic simulation

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recursive PROCEDURES FOR CONSTRAINED OPTIMIZATION PROBLEMS AND ITS APPLICATION IN SIGNAL-PROCESSING

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IEE PROCEEDINGS-VISION IMAGE AND SIGNAL PROCESSING 1995年第3期142卷 161-168页

作者： ZHENG, WX CANTONI, A VO, B TEO, KL UNIV WESTERN AUSTRALIA DEPT MATHNEDLANDSWA 6009AUSTRALIA

Many filter design problems in signal processing can be formulated as a quadratic programming problem with linear inequality constraints. The authors present new recursive procedures for solving this kind of problem. Using a constraint transcription technique, this inequality constrained quadratic programming problem can be approximated as an unconstrained minimisation problem. Two types of optimisation methods are developed to serve this unconstrained problem in a recursive adjusting manner. Analysis and simulation results on the proposed recursive procedures applied to the design of envelope-constrained filters are presented.

关键词： FIR FILTER DESIGN ADAPTIVE SIGNAL PROCESSING CONSTRAINED OPTIMIZATION recursive algorithms CONVERGENCE ANALYSIS INEQUALITY CONSTRAINTS

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recursive trust-region methods for multiscale nonlinear optimization

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SIAM JOURNAL ON OPTIMIZATION 2008年第1期19卷 414-444页

作者： Gratton, Serge Sartenaer, Annick Toint, Philippe L. CNES Toulouse France CERFACS F-31057 Toulouse France Univ Namur Dept Math B-5000 Namur Belgium

A class of trust-region methods is presented for solving unconstrained nonlinear and possibly nonconvex discretized optimization problems, like those arising in systems governed by partial differential equations. The algorithms in this class make use of the discretization level as a means of speeding up the computation of the step. This use is recursive, leading to true multilevel/multiscale optimization methods reminiscent of multigrid methods in linear algebra and the solution of partial differential equations. A simple algorithm of the class is then described and its numerical performance is shown to be numerically promising. This observation then motivates a proof of global convergence to first-order stationary points on the. ne grid that is valid for all algorithms in the class.

关键词： nonlinear optimization multiscale problems simplified models recursive algorithms convergence theory

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A fully portable high performance minimal storage hybrid format Cholesky algorithm

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ACM TRANSACTIONS ON MATHEMATICAL SOFTWARE 2005年第2期31卷 201-227页

作者： Andersen, BS Gunnels, JA Gustavson, FG Reid, JK Wasniewski, J Danish Meteorol Inst DK-2100 Copenhagen Denmark IBM Corp TJ Watson Res Ctr Yorktown Hts NY 10598 USA Rutherford Appleton Lab Didcot OX11 OQX Oxon England Tech Univ Denmark DK-2800 Lyngby Denmark

We consider the efficient implementation of the Cholesky solution of symmetric positive-definite dense linear systems of equations using packed storage. We take the same starting point as that of LINPACK and LAPACK, with the upper (or lower) triangular part of the matrix stored by columns. Following LINPACK and LAPACK, we overwrite the given matrix by its Cholesky factor. We consider the use of a hybrid format in which blocks of the matrices are held contiguously and compare this to the present LAPACK code. Code based on this format has the storage advantages of the present code but substantially outperforms it. Furthermore, it compares favorably to using conventional full format (LAPACK) and using the recursive format of Andersen et al. [2001].

关键词： algorithms performance BLAS real symmetric matrices complex Hermitian matrices positive-definite matrices Cholesky factorization and solution recursive algorithms novel packed-matrix data structures linear systems of equations

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Multi-Target Tracking using Multiple Passive Bearings-Only Asynchronous Sensors

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2008年第3期44卷 1151-1160页

作者： Musicki, Darko POB 1203 Doncaster E Vic 3109 Australia

Passive tracking relies on detection of energy emitted by zero or more targets in surveillance space. When detection occurs, the angle of arrival, or the angle between the sensor and the possible target is measured, with a measurement error. Both targets and sensors can be moving, thus additional source of error is the sensor position uncertainty. If the targets emit beams of energy randomly, then each sensor will detect each target at random times, which are independent from sensor to sensor. False detections or clutter measurements also occur at random times for each sensor. Existence, number, and position. of targets are unknown in the surveillance region. The origin of each measurement is unknown, as the measurement may be a detection from any target being tracked, or a clutter detection, or a detection from a new target. The recursive algorithm presented integrates information from measurements received by an arbitrary number of sensors, to determine the existence, number, and position of targets in a stochastic manner, given assumptions listed above. Simulations show the effectiveness of this approach in a multi-target scenario.

关键词： clutter direction-of-arrival estimation target tracking angle of arrival clutter measurements multi-target tracking multiple passive bearings-only asynchronous sensors surveillance space recursive algorithms Angle of arrival clutter Sensors Target tracking Error Sources Error measure Direction of arrival estimation

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Optimal minimum variance estimation for non-linear discrete-time multichannel systems

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IET SIGNAL PROCESSING 2010年第6期4卷 618-629页

作者： Grimble, M. J. Naz, S. Ali Univ Strathclyde Ind Control Ctr Glasgow G1 1QE Lanark Scotland

A non-linear operator approach to estimation in discrete-time multivariable systems is described. It involves inferential estimation of a signal which enters a communication channel that contains non-linearities and transport delays. The measurements are assumed to be corrupted by a coloured noise signal correlated with the signal to be estimated. The solution of the non-linear estimation problem is obtained using non-linear operators. The signal and noise channels may be grossly non-linear and are represented in a very general non-linear operator form. The resulting so-called Wiener non-linear minimum variance estimation algorithm is relatively simple to implement. The optimal non-linear estimator is derived in terms of the non-linear operators and can be implemented as a recursive algorithm using a discrete-time non-linear difference equation. In the limiting case of a linear system, the estimator has the form of a Wiener filter in discrete-time polynomial matrix system form. A non-linear channel equalisation problem is considered for the design example.

关键词： Aurora A Signaling Pathway recursive algorithms overrun a signal multiple input multiple output systems signals Difference equation Colored noise discrete-time Wiener filters Polynomial matrices clear (a signal)

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ORDER STATISTIC DISTRIBUTIONS WITH MULTIPLE WINDOWS

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IEEE TRANSACTIONS ON INFORMATION THEORY 1991年第2期37卷 436-442页

作者： BONCELET, CG Department of Electrical Engineering University of Delaware Newark DE USA

algorithms for computing the distributions of order statistic related estimators with moving or multiple windows are presented. These algorithms can be used to compute joint distributions of moving window estimators, such as moving median filters, or of estimators made from ranking operations on multiple windows, such as many "stacked" or "morphological" filters. The algorithms presented here make no distributional assumptions on the underlying random variables, but do make assumptions on the dependency between them. For instance, the random variables may be independent, Markov, or Markov corrupted by an independent noise source. Unlike other approaches, these algorithms have polynomial complexity in the number of random variables. It is shown how these algorithms are easily implemented. Finally, two computational examples of the behavior of median filters are given.

关键词： ORDER STATISTIC PROBABILITY CALCULATION recursive algorithms MEDIAN FILTERS

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