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Robust design with Variability Response Functions;an alternative approach

STRUCTURAL SAFETY 2016年 59卷 1-8页

作者： Kokkinos, Odysseas Papadopoulos, Vissarion Natl Tech Univ Athens Inst Struct Anal & Seism Res 9 Iroon PolytechZografou Campus Athens 15780 Greece

In this work a different Robust Design Optimization (RDO) approach is proposed implementing the concept of Variability Response Function (VRF), which is a function that when combined with the power spectral density of the stochastic field that models the system's uncertainty, formulates an integral expression for the variance of the system's response. The basic idea is to exploit a very well-known property of the VRF, which is its independence of the stochastic system parameters, in order to obtain global optima that depend only on the deterministic parameters of the problem. This way, optimal structural designs are achieved which are globally insensitive to uncertainties, that is to say they are free of the spectral-distribution characteristics of the stochastic fields modeling the uncertainties. This is achieved by setting in addition to the total material cost, the maximum VRF value as an objective function. The advantages of using the proposed methodology over traditional Robust Design Optimization are illustrated through an application to a frame-type structure where it is demonstrated that the designs achieved through classical RDO for a given stochastic field description are not optimal for a variation on the spectral properties of the random field modeling the system uncertainty, while optimal designs obtained with the VRF-based RDO remain optimum for the worst case scenario stochastic fields. (C) 2015 Elsevier Ltd. All rights reserved.

关键词： Variability Response Functions Stochastic finite element analysis Robust Design Optimization Stochastic dynamic systems multi objective genetic algorithm

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Seismic response control of adjacent buildings coupled by semi-active shared TMD

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INTERNATIONAL JOURNAL OF STEEL STRUCTURES 2016年第2期16卷 647-656页

作者： Kim, Hyun-Su Sunmoon Univ Div Architecture Architectural & Civil Engrg Asan South Korea

A tuned mass damper (TMD) is one of the most widely used and accepted systems for the vibration control of building structures subjected to earthquake loads. In large cities, tall buildings are now being constructed closer together. A shared tuned mass damper has been proposed for the vibration control of adjacent buildings. If a shared TMD is designed to effectively reduce the dynamic responses of one building, the control performance for the other building deteriorates. This is because the stiffnesses and damping coefficients of the passive shared TMD connected to each building are fixed. A semi-active shared TMD was proposed in this study to immediately adjust the control force of the shared TMD to each building connected by the shared TMD. The control performance of the semi-active shared TMD was investigated using numerical analyses. For this purpose, two 8-story buildings were used as example structures. Magnetorheological (MR) dampers were used to create the semi-active shared TMD. A multi-input multi-output (MIMO) fuzzy logic controller (FLC) was developed to control the command voltages sent to each MR damper. A multi-objective genetic algorithm was employed to optimize the MIMO FLC. An artificial ground motion was used as an excitation. Based on numerical analyses, it was shown that a semi-active sheared TMD can provide better control performance than that of a conventional TMD, although the semi-active sheared TMD uses only half of the mass used by the conventional TMD system.

关键词： shared tuned mass damper seismic response control mr damper fuzzy logic controller multi objective genetic algorithm

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A Hybrid Control Scheme for a Twin Rotor System with multi objective genetic algorithm

A Hybrid Control Scheme for a Twin Rotor System with Multi O...

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12th International Conference on Computer Modelling and Simulation (UKSim)

作者： Toha, S. F. Tokhi, M. O. Univ Sheffield Dept Automat Control & Syst Engn Sheffield S10 2TN S Yorkshire England

ISBN: (纸本)9780769540160

Control of vibration suppressions is crucial for applications in engineering particularly in the area of aircraft system. A hybrid control approach encompasses of using a feedforward intelligent command shaping technique with combination of intelligent PID feedback control is presented in this paper. The advantage of using command shaping is to reduce system vibration. However, it can cause delay in system response resulting to a conflict between vibration suppression and rise time response. multi objective genetic algorithm is employ in this work to determine a set of solutions for the amplitudes and corresponding time locations of impulses on an extra sensitive (EI) command shaping as well as gain parameters for the PID controller. The effectiveness of the proposed technique is assessed both in the time domain and the frequency domain. Moreover, a comparative assessment of the performance of the technique with the system response and unshaped finite step input is presented.

关键词： Vibration suppression twin rotor system multi objective genetic algorithm

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A Model for Sustainable Site Layout Design of Social Housing with Pareto genetic algorithm: SSPM 1

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16th International CAAD Futures Conference

作者： Aksoy, Yazgi Badem Cagdas, Gulen Balaban, Ozgun Istanbul Tech Univ TR-80626 Istanbul Turkey

ISBN: (数字)9783662473863

ISBN: (纸本)9783662473863;9783662473856

Nowadays as the aim to reduce the environmental impact of buildings becomes more apparent, a new architectural design approach is gaining momentum called sustainable architectural design. Sustainable architectural design process includes some regulations itself, which requires calculations, comparisons and consists of several possible conflicting objectives that need to be considered together. A successful green building design can be performed by the creation of alternative designs generated according to all the sustainability parameters and local regulations in conceptual design stage. As there are conflicting criteria's according to LEED and BREAM sustainable site parameters, local regulations and local climate conditions, an efficient decision support system can be developed by the help of Pareto based non-dominated genetic algorithm (NSGA-II) which is used for several possibly conflicting objectives that need to be considered together. In this paper, a model which aims to produce site layout alternatives according to sustainability criteria for cooperative apartment house complexes, will be mentioned.

关键词： Sustainable site layout design multi objective genetic algorithm LEED-BREEAM

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Synaptic inputs are tuned to match intrinsic properties to maintain phase in oscillatory neural networks

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BMC Neurosci 2015年第SUPPL 1期16卷 P173-P173页

作者： Haroon Anwar Jordan Storms Farzan Nadim Federated Department of Biological Sciences New Jersey Institute of Technology Newark NJ 07102 USA Rutgers University-Newark Newark NJ 07102 USA

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Shape-Based Design of Low-Thrust Trajectories to Cislunar Lagrangian Point

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2014年第4期37卷 1329-+页

作者： Vellutini, Elena Avanzini, Giulio Politecn Torino Dept Mech & Aerosp Engn I-10129 Turin Italy Univ Salento Dept Engn I-73100 Lecce Italy

The shape function is defined on the basis of a few parameters that can be modified by means of an optimization algorithm to improve transfer performance in some sense and guarantee its feasibility. The final solution does not need to be the optimal one, but it should provide a reasonable first guess for more sophisticated optimization procedures. Most of the applications of the shape-based approach are proposed in the framework of the two-body problem, where the spacecraft moves under the action of low thrust and a single primary body. This approach is reasonable for most mission scenarios, during preliminary steps of mission design, when approximate solutions are sufficient and a single primary mass is considered during each mission segment. However sometimes it is necessary to account for gravity pull from more than a single primary mass.

关键词： Thrust Lambert's Problem Shape Functions Earth Propellant Gravity Assist Trajectories Flight Path Angle Low Thrust Propulsion multi objective genetic algorithm Periapsis

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multispacecraft Refueling Optimization Considering the J2 Perturbation and Window Constraints

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JOURNAL OF GUIDANCE CONTROL AND DYNAMICS 2014年第1期37卷 111-122页

作者： Zhang, Jin Parks, Geoffrey T. Luo, Ya-zhong Tang, Guo-jin Natl Univ Def Technol Coll Aerosp Sci & Engn Changsha 410073 Hunan Peoples R China Univ Cambridge Dept Engn Cambridge CB2 1PZ England

The optimization of a near-circular low-Earth-orbit multispacecraft refueling problem is studied. The refueling sequence, service time, and orbital transfer time are used as design variables, whereas the mean mission completion time and mean propellant consumed by orbital maneuvers are used as design objectives. The J2 term of the Earth's nonspherical gravity perturbation and the constraints of rendezvous time windows are taken into account. A hybrid-encoding genetic algorithm, which uses normal fitness assignment to find the minimum mean propellant-cost solution and fitness assignment based on the concept of Pareto-optimality to find multi-objective optimal solutions, is presented. The proposed approach is demonstrated for a typical multispacecraft refueling problem. The results show that the proposed approach is effective, and that the J2 perturbation and the time-window constraints have considerable influences on the optimization results. For the problems in which the J2 perturbation is not accounted for, the optimal refueling order can be simply determined as a sequential order or as the order only based on orbital-plane differences. In contrast, for the problems that do consider the J2 perturbation, the optimal solutions obtained have a variety of refueling orders and use the drift of nodes effectively to reduce the propellant cost for eliminating orbital-plane differences.

关键词： Propellant Low Thrust Maneuvers multi objective genetic algorithm Nonlinear Programming Earth Orbital Inclination Target Spacecraft Satellite Formation Argument of Latitude Constellations

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A multi-objective, Active Fuzzy Force Controller in control of Flexible Wiper System

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LATIN AMERICAN JOURNAL OF SOLIDS AND STRUCTURES 2014年第9期11卷 1490-1514页

作者： Zolfagharian, Ali Ghasemi, Seyed Ebrahim Imani, Misagh Islamic Azad Univ Dept Mech Engn Qaemshahr Branch Qaemshahr Iran Islamic Azad Univ Young Researchers & Elite Club Qaemshahr Branch Qaemshahr Iran Islamic Azad Univ Dept Mech Engn Sari Branch Sari Iran

Chaotic vibration has been identified in the flexible automotive wiper blade at certain wiping speeds. This irregular vibration not only decreases the wiping efficiency, but also degrades the driving comfort. A reliable nonlinear system identification namely nonlinear auto regressive exogenous Elman neural network (NARXENN) was adopted in first stage of this survey to model the flexible dynamics of wiper blade with acquired experimental data. In controller design part, taking into account environmental and external disturbances that cause changes in the dynamic characteristics of the system demanded a robust controller to make a trade off between the worst and best scenario. An active fuzzy force controller (AFLC) supervised by multi objective genetic algorithm (MOGA) is developed to keep both interests of noise and vibration redaction of automobile wiper blade at the reasonable rise time.

关键词： Automotive wiper system identification fuzzy logic active force control multi objective genetic algorithm

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Unwanted noise and vibration control using finite element analysis and artificial intelligence

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APPLIED MATHEMATICAL MODELLING 2014年第9-10期38卷 2435-2453页

作者： Zolfagharian, Ali Noshadi, Amin Khosravani, Mohammad Reza Zain, Mohd Zarhamdy Md. Univ Teknol Malaysia Fac Mech Engn Dept Syst Dynam & Control Johor Baharu Malaysia Victoria Univ Fac Hlth Engn & Sci Sch Sci & Engn Melbourne Vic 8001 Australia Univ Siegen Chair Solid Mech D-57068 Siegen Germany

A mechatronic approach integrating both passive and active controllers is presented in this study to deal with unwanted noise and vibration produced in an automobile wiper system operation. Wiper system is a flexible structure with high order, nonlinear model that is considered as a multi objective control problem since there is a conflict between its functionality quality in wiping and generated unwanted noise and vibration. A passive control technique using multi body system (MBS) model and finite element analysis (FEA) is introduced to identify the potential of the effectiveness of the physical parameters of wiper blade to give appropriate range to reduce the unwanted noise and vibration in the system. While, the significant contribution of active controller is to deal with uncertainties exerted to system within wiper operation. In passive control stage, natural frequencies of a uniblade automobile wiper are determined using modal testing. Later, a 3-dimensional model of a wiper blade assembly is developed in multi body system design to investigate the good validation test and agreement of the physical behavior of the system in experiment with finite element analysis. Parametric modification via complex eigenvalue is adopted to predict instability of the wiper blade. In active control level, experimental data collected from the wiper system during its operation. A system identification model named nonlinear auto regressive exogenous Elman neural network (NARXENN) is developed for implying the active controller. A bi-level adaptive-fuzzy controller is brought in whose parameters are tuned simultaneously by a multi objective genetic algorithm (MOGA) to deal with the conflict interests in wiper control problem. (C) 2013 Elsevier Inc. All rights reserved.

关键词： Automotive wiper Finite element analysis Non-linear system identification Fuzzy logic multi objective genetic algorithm

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Practical multi-objective controller for preventing noise and vibration in an automobile wiper system

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SWARM AND EVOLUTIONARY COMPUTATION 2013年 8卷 54-68页

作者： Zolfagharian, Ali Noshadi, Amin Zain, Mohd Zarhamdy Md. Abu Bakar, Abd Rahim Univ Teknol Malaysia Fac Mech Engn Dept Syst Dynam & Control Johor Baharu 81310 Johor Malaysia Victoria Univ Fac Hlth Engn & Sci Sch Sci & Engn Melbourne Vic 8001 Australia Univ Teknol Malaysia Fac Mech Engn Dept Automot Engn Johor Baharu 81310 Johor Malaysia

This paper presents an approach using a multi-objective controller to prevent noise and vibration generated by the wiper blade during its wiping operation. Firstly, this paper focuses on the experimental approach to collect noise and vibration data from a car wiper system during its operation and secondly, to develop black box model of the wiper system using nonparametric approach of system identification known as nonlinear auto regressive exogenous Elman neural network (NARXENN). Finally, a novel closed loop iterative input shaping controller whose parameters are tuned simultaneously by a Pareto based multi objective genetic algorithm (MOGA) are proposed and simulated in such a way that it can prevent unwanted noise and vibration in the wiper system. The main contribution of this work rather the previous studies of automobile wiper system is to develop a novel multi-objective control strategy whereby an automobile wiper blade is moved within its sweep workspace in the least amount of time with minimum noise and vibration. (C) 2012 Elsevier B.V. All rights reserved.

关键词： Automotive wiper Noise and vibration Non-linear system identification Input shaping Iterative learning multi objective genetic algorithm

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