Simultaneous Type and Dimensional Synthesis of Mechanisms by Genetic Algorithms

Author(s):  
W. Eugene Fang

Abstract Based on global search/optimization techniques called genetic algorithms, a new approach to the conceptual design of mechanisms is proposed. Emulating “natural” genetics and selection, competing types of mechanisms are treated as species and different dimensions are evaluated for each type simultaneously. The problem formulation is straight-forward, similar to an optimization problem. The result may be a spectrum of similar or different mechanisms, depending on whether multiple optimal solutions exist. The computational power required to utilize this approach is acceptable for most conceptual design problems.

Author(s):  
Ronaldo Gutierrez ◽  
Yong Zeng ◽  
Xuan Sun ◽  
Suo Tan ◽  
Xiaoguang Deng ◽  
...  

Problem formulations in natural language imply imprecision, ambiguity, incompleteness, conflict and inconsistency between requirements in a design problem. Recursive Object Model (ROM) based problem formulation in conceptual design extracts complete product requirement from design problems structured initially in natural language. Since ROM carries certain semantic and syntactic information implied in natural language, it is used to formulate a design problem through a question asking approach. The scope of this paper is to present an updated algorithm, question templates, rules and detailed procedures to ask generic questions based on ROM representations. Generic questions are needed for the clarification and extension of the meaning of a design problem in order to overcome the imprecisions, ambiguities, conflicts and inconsistencies of problem descriptions in natural language. The updated algorithm, question templates, rules and detailed procedures for asking generic questions are used in a case study to formulate the development of a Total Quality Management system (TQMS).


Author(s):  
A K Khare ◽  
A C Rao

Structural error synthesis of mechanisms is usually carried out either by the precision point approach or by using optimization techniques. A new approach for such problems using the reliability concept is presented in this paper. Besides being simple, this approach leads to a closed form solution and the mechanism can be designed to perform with any desired reliability. Its application is illustrated by means of a numerical example and the results are compared with those available.


2006 ◽  
Vol 34 (3) ◽  
pp. 170-194 ◽  
Author(s):  
M. Koishi ◽  
Z. Shida

Abstract Since tires carry out many functions and many of them have tradeoffs, it is important to find the combination of design variables that satisfy well-balanced performance in conceptual design stage. To find a good design of tires is to solve the multi-objective design problems, i.e., inverse problems. However, due to the lack of suitable solution techniques, such problems are converted into a single-objective optimization problem before being solved. Therefore, it is difficult to find the Pareto solutions of multi-objective design problems of tires. Recently, multi-objective evolutionary algorithms have become popular in many fields to find the Pareto solutions. In this paper, we propose a design procedure to solve multi-objective design problems as the comprehensive solver of inverse problems. At first, a multi-objective genetic algorithm (MOGA) is employed to find the Pareto solutions of tire performance, which are in multi-dimensional space of objective functions. Response surface method is also used to evaluate objective functions in the optimization process and can reduce CPU time dramatically. In addition, a self-organizing map (SOM) proposed by Kohonen is used to map Pareto solutions from high-dimensional objective space onto two-dimensional space. Using SOM, design engineers see easily the Pareto solutions of tire performance and can find suitable design plans. The SOM can be considered as an inverse function that defines the relation between Pareto solutions and design variables. To demonstrate the procedure, tire tread design is conducted. The objective of design is to improve uneven wear and wear life for both the front tire and the rear tire of a passenger car. Wear performance is evaluated by finite element analysis (FEA). Response surface is obtained by the design of experiments and FEA. Using both MOGA and SOM, we obtain a map of Pareto solutions. We can find suitable design plans that satisfy well-balanced performance on the map called “multi-performance map.” It helps tire design engineers to make their decision in conceptual design stage.


AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 51-61 ◽  
Author(s):  
M. C. Sharatchandra ◽  
Mihir Sen ◽  
Mohamed Gad-el-Hak

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1581
Author(s):  
Alfonso Hernández ◽  
Aitor Muñoyerro ◽  
Mónica Urízar ◽  
Enrique Amezua

In this paper, an optimization procedure for path generation synthesis of the slider-crank mechanism will be presented. The proposed approach is based on a hybrid strategy, mixing local and global optimization techniques. Regarding the local optimization scheme, based on the null gradient condition, a novel methodology to solve the resulting non-linear equations is developed. The solving procedure consists of decoupling two subsystems of equations which can be solved separately and following an iterative process. In relation to the global technique, a multi-start method based on a genetic algorithm is implemented. The fitness function incorporated in the genetic algorithm will take as arguments the set of dimensional parameters of the slider-crank mechanism. Several illustrative examples will prove the validity of the proposed optimization methodology, in some cases achieving an even better result compared to mechanisms with a higher number of dimensional parameters, such as the four-bar mechanism or the Watt’s mechanism.


2005 ◽  
Vol 22 (2) ◽  
pp. 128-135 ◽  
Author(s):  
Brendon J. Brewer ◽  
Geraint F. Lewis

AbstractGravitational lensing can magnify a distant source, revealing structural detail which is normally unresolvable. Recovering this detail through an inversion of the influence of gravitational lensing, however, requires optimisation of not only lens parameters, but also of the surface brightness distribution of the source. This paper outlines a new approach to this inversion, utilising genetic algorithms to reconstruct the source profile. In this initial study, the effects of image degradation due to instrumental and atmospheric effects are neglected and it is assumed that the lens model is accurately known, but the genetic algorithm approach can be incorporated into more general optimisation techniques, allowing the optimisation of both the parameters for a lensing model and the surface brightness of the source.


2005 ◽  
Vol 21 (3) ◽  
pp. 449-456 ◽  
Author(s):  
T. Huang ◽  
M. Li ◽  
X.M. Zhao ◽  
J.P. Mei ◽  
D.G. Chetwynd ◽  
...  

Since early 1980, BP has been developing the conceptual design of a Single-Well Oil Production System or SWOPS. This paper outlines the concept and discusses the design and the operational criteria that have been applied in this early work. It further examines some of the innovative areas of technology that have been included in this new approach and outlines the work of the detail design phase, which has just started.


Author(s):  
Mahmoud Dinar ◽  
Yong-Seok Park ◽  
Jami J. Shah

Conventional syllabi of engineering design courses either do not pay enough attention to conceptual design skills, or they lack an objective assessment of those skills to show students’ progress. During a semester-long course of advanced engineering product design, we assigned three major design projects to twenty five students. For each project we asked them to formulate the problems in the Problem Formulator web-based testbed. In addition, we collected sketches for all three design problems, feasibility analyses for the last two, and a working prototype for the final project. We report the students’ problem formulation and ideation in terms of a set of nine problem formulation characteristics and ASU’s ideation effectiveness metrics respectively. We discuss the limitations that the choice of the design problems caused, and how the progress of a class of students during a semester-long design course resulted in a convergence in sets of metrics that we have defined to characterize problem formulation and ideation. We also review the results of students of a similar course which we reported last year in order to find common trends.


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