Modeling of a Controlled Service Platform: Proposals for an Optimal Layout

1996 ◽  
Author(s):  
H. Eschenauer ◽  
P. Neuser
Keyword(s):  
Optimization Problem ◽  
Optimization Procedure ◽  
Optimal Layout ◽  
Fe Method ◽  
Service Platform ◽  
System Reduction ◽  
Extreme Load ◽  
Structural Responses ◽  
Improved Design ◽  
Structural Optimization Problem

Abstract As an example of complex systems a controlled service platform is treated, for which an improved design has to be determined. Two substitute models that simplify the real system to a different degree are employed for the calculation of the structural responses by means of the Finite-Element (FE)-Method. The structural analyses are limited to the consideration of the system’s free vibration behaviour, as well as the displacements and stresses in an extreme load case, called bumper impact. A further system reduction is achieved by using sub-structuring and the reduction according to Guyan. The structural optimization problem is solved by means of the optimization procedure SAPOP that is based on the so-called Three-Columns-Concept. Results are given for a design optimized with respect to mass, first eigenfrequency, and stress.

scholarly journals OPTIMIZATION OF GRILLAGES USING GENETIC ALGORITHMS FOR INTEGRATING MATLAB AND FORTRAN ENVIRONMENTS / MATLAB IR FORTRAN APLINKŲ SUJUNGIMAS ROSTVERKAMS OPTIMIZUOTI GENETINIAIS ALGORITMAIS

2013 ◽  
Vol 6 (4) ◽  
pp. 564-568
Author(s):  
Darius Mačiūnas ◽  
Juozas Kauna ◽  
Dmitrij Šešok
Keyword(s):  
Genetic Algorithm ◽  
Global Optimization ◽  
Optimization Problem ◽  
Optimization Procedure ◽  
Optimal Layout ◽  
Reactive Force ◽  
Topology Optimization Problem ◽  
Original Algorithm ◽  
Fortran Programming Language

The purpose of the paper is to present technology applied for the global optimization of grillage-type pile foundations (further grillages). The goal of optimization is to obtain the optimal layout of pile placement in the grillages. The problem can be categorized as a topology optimization problem. The objective function is comprised of maximum reactive force emerging in a pile. The reactive force is minimized during the procedure of optimization during which variables enclose the positions of piles beneath connecting beams. Reactive forces in all piles are computed utilizing an original algorithm implemented in the Fortran programming language. The algorithm is integrated into the MatLab environment where the optimization procedure is executed utilizing a genetic algorithm. The article also describes technology enabling the integration of MatLab and Fortran environments. The authors seek to evaluate the quality of a solution to the problem analyzing experimental results obtained applying the proposed technology. Santrauka Straipsnyje pateikiama sijynų tipo pamatų (toliau sijynų) globalaus optimizavimo technologija. Optimizavimo tikslas – nustatyti optimalų polių išdėstymą sijynuose. Šis uždavinys priskiriamas topologijos optimizavimo uždavinių grupei. Tikslo funkciją sudaro maksimali poliuje kylanti atraminė reakcijos jėga, kuri minimizuojama optimizavimo procese. Šio uždavinio projektavimo kintamieji - polių padėtys po jungiančiosiomis sijyno sijomis. Tiesioginis reakcijų poliuose skaičiavimo uždavinys sprendžiamas originaliu algoritmu, sukurtu Fortran programavimo kalba. Šis algoritmas juodosios dėžės principu jungiamas prie MatLab aplinkos, kurioje genetiniu algoritmu sprendžiamas optimizavimo uždavinys. Straipsnyje taip pat aprašyta technologija, kuri leidžia sujungti Matlab ir Fortran aplinkas, t. y. iš Matlab aplinkos iškviesti Fortran paprogramį. Analizuodami eksperimentinius duomenis autoriai bando įvertinti gaunamų sprendinių kokybę.

scholarly journals Least-thickness symmetric circular masonry arch of maximum horizontal thrust

2021 ◽  
Author(s):  
Giuseppe Cocchetti ◽  
Egidio Rizzi
Keyword(s):  
Optimization Problem ◽  
Research Work ◽  
Complementary Information ◽  
Masonry Arch ◽  
Collapse Mode ◽  
Hinge Position ◽  
Explicit Representations ◽  
Horizontal Thrust ◽  
Structural Optimization Problem ◽  
Typical Solution

AbstractThis analytical note shall provide a contribution to the understanding of general principles in the Mechanics of (symmetric circular) masonry arches. Within a mainstream of previous research work by the authors (and competent framing in the dedicated literature), devoted to investigate the classical structural optimization problem leading to the least-thickness condition under self-weight (“Couplet-Heyman problem”), and the relevant characteristics of the purely rotational five-hinge collapse mode, new and complementary information is here analytically derived. Peculiar extremal conditions are explicitly inspected, as those leading to the maximum intrinsic non-dimensional horizontal thrust and to the foremost wide angular inner-hinge position from the crown, both occurring for specific instances of over-complete (horseshoe) arches. The whole is obtained, and confronted, for three typical solution cases, i.e., Heyman, “CCR” and Milankovitch instances, all together, by full closed-form explicit representations, and elucidated by relevant illustrations.

Dynamic multi-objective matrix control for a class of switched systems

2021 ◽  
pp. 014233122199338
Author(s):  
Ali Thamallah ◽  
Anis Sakly ◽  
Faouzi M’Sahli
Keyword(s):  
Switched Systems ◽  
Optimization Problem ◽  
Control Method ◽  
Optimization Procedure ◽  
Control Law ◽  
Dynamic Matrix Control ◽  
General Reference ◽  
Multi Objective ◽  
Dynamic Matrix ◽  
Matrix Control

This article focuses on the tracking and stabilizing issues of a class of discrete switched systems. These systems are characterized by unknown switching sequences, a non-minimum phase, and time-varying or dead modes. In particular, for those governed by an indeterminate switching signal, it is very complicated to synthesize a control law able to systematically approach general reference-tracking difficulties. Taking into account the difficulty to express the dynamic of this class of systems, the present paper presents a new Dynamic matrix control method based on the multi-objective optimization and the truncated impulse response model. The formulation of the optimization problem aims to approach the general step-tracking issues under persistent and indeterminate mode changes and to overcome the stability problem along with retaining as many desirable features of the standard dynamic matrix control (DMC) method as possible. In addition, the formulated optimization problem integrates estimator variables able to manipulate the optimization procedure in favor of the active mode with an appropriate adjustment. It also provides a progressive and smooth multi-objective control law even in the presence of problems whether in subsystems or switching sequences. Finally, simulation examples and comparison tests are conducted to illustrate the potentiality and effectiveness of the developed method.

Optimization of the Robot Calibration Process

1992 ◽  
Author(s):  
G. Zak ◽  
R. G. Fenton ◽  
B. Benhabib
Keyword(s):  
Optimization Problem ◽  
Kinematic Model ◽  
Optimization Procedure ◽  
Calibration Procedure ◽  
Residual Error ◽  
Industrial Robots ◽  
Multiple Objective Optimization ◽  
Robot Calibration ◽  
Calibration Process ◽  
The Cost

Abstract Most industrial robots cannot be off-line programmed to carry out a task accurately, unless their kinematic model is suitably corrected through a calibration procedure. However, proper calibration is an expensive and time-consuming procedure due to the highly accurate measurement equipment required and due to the significant amount of data that must be collected. To improve the efficiency of robot calibration, an optimization procedure is proposed in this paper. The objective of minimizing the cost of the calibration is combined with the objective of minimizing the residual error after calibration in one multiple-objective optimization. Prediction of the residual error for a given calibration process presents the main difficulty for implementing the optimization. It is proposed that the residual error is expressed as a polynomial function. This function is obtained as a result of fitting a response surface to either experimental or simulated sample estimates of the residual error. The optimization problem is then solved by identifying a reduced set of possible solutions, thus greatly simplifying the decision maker’s choice of an effective calibration procedure. An application example of this method is also included.

scholarly journals Optimal design of a DC MHD pump by simulated annealing method

2014 ◽  
Vol 11 (2) ◽  
pp. 339-350
Author(s):  
Khadidja Bouali ◽  
Fatima Kadid ◽  
Rachid Abdessemed
Keyword(s):  
Simulated Annealing ◽  
Optimal Design ◽  
Objective Function ◽  
Design Problem ◽  
Design Methodology ◽  
Optimization Problem ◽  
Optimization Procedure ◽  
Simulated Annealing Method ◽  
Direct Interpretation ◽  
Annealing Method

In this paper a design methodology of a magnetohydrodynamic pump is proposed. The methodology is based on direct interpretation of the design problem as an optimization problem. The simulated annealing method is used for an optimal design of a DC MHD pump. The optimization procedure uses an objective function which can be the minimum of the mass. The constraints are both of geometrics and electromagnetic in type. The obtained results are reported.

Force identification under unknown initial conditions by using concomitant mapping matrix and sparse regularization

2020 ◽  
pp. 107754632094469
Author(s):  
Xijun Ye ◽  
Chudong Pan
Keyword(s):  
Optimization Problem ◽  
Initial Conditions ◽  
Sparse Regularization ◽  
Force Identification ◽  
Moving Force ◽  
Dynamic Forces ◽  
Force Reconstruction ◽  
Structural Responses ◽  
One Step ◽  
Regularization Strategy

Unknown initial conditions can affect the identified accuracy of dynamic forces. Direct measurement of initial conditions is relatively difficult. This study proposes a sparse regularization–based method for identifying forces considering influences of unknown initial conditions. The initial conditions are embedded in a classical governing equation of force identification. The key idea is to introduce a concept of concomitant mapping matrix for reasonably expressing the initial conditions. First, a dictionary is introduced for expanding the dynamic forces. Then, the concomitant mapping matrix is formulated by using free vibrating responses, which correspond to structural responses happening after the structure is subjected to each atom of the force dictionary. A sparse regularization strategy is applied for solving the ill-conditioned equation. After that, the problem of force identification is converted into an optimization problem, and it can be solved by using a one-step strategy. Numerical simulations are carried out for verifying the feasibility and effectiveness of the proposed method. Illustrated results clearly show the applicability and robustness of the proposed method for dealing with force reconstruction and moving force identification.

Size and Pretension Optimization Design of Deployable Cable-Frame Antenna Structures

2015 ◽  
Vol 777 ◽  
pp. 101-105
Author(s):  
Ya Li Zong ◽  
Hong Jun Cao ◽  
Ya Jing Ma
Keyword(s):  
Structural Optimization ◽  
Optimization Model ◽  
Optimization Design ◽  
Optimization Problem ◽  
Antenna Structure ◽  
Cable Network ◽  
Surface Precision ◽  
Supporting Frame ◽  
Member Size ◽  
Structural Optimization Problem

In this paper, the structural optimization problem of a deployable cable-frame antenna consisting of a cable network and a supporting frame is discussed in detail. Firstly, the initial equilibrium problem of the cable-frame antenna structure is discussed with emphasis on the realization convenience. An optimization model is proposed to get a set of uniformly distributed cable pretensions whilst satisfying the surface precision requirement. Secondly, the optimization of the member size and cable tensions are integrated in one optimization model in which both folded and deployed status are considered. Finally, a 10-meter antenna is optimized with good results which indicates that the proposed method is feasible and effective.

Modeling and Identification of a Class of Servomechanism Systems With Stick-Slip Friction

1988 ◽  
Vol 110 (3) ◽  
pp. 324-328 ◽  
Author(s):  
Ka C. Cheok ◽  
Hongxing Hu ◽  
Nan K. Loh
Keyword(s):  
Nonlinear Optimization ◽  
Optimization Problem ◽  
Optimization Procedure ◽  
Simplex Algorithm ◽  
Identification Algorithm ◽  
Stick Slip ◽  
Process Identification ◽  
Nonlinear Optimization Problem ◽  
System Parameters ◽  
Input Signals

This paper describes a technique for modeling and identifying a class of nonlinear servomechanism systems with stick-slip friction. The physics of the stick-slip friction is considered in modeling the process. Identification of the system parameters is formulated as a nonlinear optimization problem. A modified simplex algorithm is proposed as the optimization procedure. The difficulties encountered in choosing identification algorithm and input signals for the problem are discussed. A simulation example of a servomotor system is provided.

An Improved Initial Population Strategy for Compliant Mechanism Designs Using Evolutionary Optimization

2008 ◽  
Author(s):  
Deepak Sharma ◽  
Kalyanmoy Deb ◽  
N. N. Kishore
Keyword(s):  
Local Search ◽  
Optimization Problem ◽  
Optimization Procedure ◽  
Evolutionary Optimization ◽  
Initial Population ◽  
Nsga Ii ◽  
Trade Off ◽  
Continuum Structures ◽  
Population Strategy ◽  
Straight Lines

In this paper, an improved initial random population strategy using a binary (0–1) representation of continuum structures is developed for evolving the topologies of path generating complaint mechanism. It helps the evolutionary optimization procedure to start with the structures which are free from impracticalities such as ‘checker-board’ pattern and disconnected ‘floating’ material. For generating an improved initial population, intermediate points are created randomly and the support, loading and output regions of a structure are connected through these intermediate points by straight lines. Thereafter, a material is assigned to those grids only where these straight lines pass. In the present study, single and two-objective optimization problems are solved using a local search based evolutionary optimization (NSGA-II) procedure. The single objective optimization problem is formulated by minimizing the weight of structure and a two-objective optimization problem deals with the simultaneous minimization of weight and input energy supplied to the structure. In both cases, an optimization problem is subjected to constraints limiting the allowed deviation at each precision point of a prescribed path so that the task of generating a user-defined path is accomplished and limiting the maximum stress to be within the allowable strength of material. Non-dominated solutions obtained after NSGA-II run are further improved by a local search procedure. Motivation behind the two-objective study is to find the trade-off optimal solutions so that diverse non-dominated topologies of complaint mechanism can be evolved in one run of optimization procedure. The obtained results of two-objective optimization study is compared with an usual study in which material in each grid is assigned at random for creating an initial population of continuum structures. Due to the use of improved initial population, the obtained non-dominated solutions outperform that of the usual study. Different shapes and nature of connectivity of the members of support, loading and output regions of the non-dominated solutions are evolved which will allow the designers to understand the topological changes which made the trade-off and will be helpful in choosing a particular solution for practice.

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