Optimum Synthesis of Planar Mechanisms for Path Generation Based on a Combined Discrete Fourier Descriptor

2015 ◽  
Vol 7 (4) ◽  
Author(s):  
Wen-Yi Lin
Keyword(s):  
Synthesis Method ◽  
Optimization Method ◽  
Path Generation ◽  
Fourier Descriptor ◽  
Planar Mechanisms ◽  
Two Phase ◽  
Phase Synthesis ◽  
Optimum Synthesis ◽  
Centroid Distance ◽  
The One

A two-phase synthesis method is described, which is capable of solving quite challenging path generation problems. A combined discrete Fourier descriptor (FD) is proposed for shape optimization, and a geometric-based approach is used for the scale–rotation–translation synthesis. The combined discrete FD comprises three shape signatures, i.e., complex coordinates (CCs), centroid distance (CD), and triangular centroid area (TCA), which can capture greater similarity of shape. The genetic algorithm–differential evolution (GA–DE) optimization method is used to solve the optimization problem. The proposed two-phase synthesis method, based on the combined discrete FD, successfully solves the challenging path generation problems with a relatively small number of function evaluations. A more accurate path shape can be obtained using the combined FD than the one-phase synthesis method. The obtained coupler curves approximate the desired paths quite well.

Optimum Synthesis of Rigid Mechanisms Using a Dynamic Ant-Search Method With Sensitivity Analysis

2019 ◽  
Author(s):  
Nadim Diab ◽  
Omar Itani ◽  
Ahmad Smaili
Keyword(s):  
Sensitivity Analysis ◽  
Optimization Technique ◽  
Design Parameters ◽  
Neighborhood Search ◽  
Intensity Level ◽  
Path Generation ◽  
Exploration And Exploitation ◽  
Planar Mechanisms ◽  
Optimum Synthesis ◽  
Synthesis Of Mechanisms

Abstract Four-bar linkages are commonly used mechanisms in various mechanical systems and components. Several techniques for optimum synthesis of planar mechanisms have been suggested in literature such as the Genetic, Tabu, Simulated Annealing, Swarm-Based and many other algorithms. This paper covers optimization of four-bar mechanisms with path generation tasks using a Dynamic Ant Search (DAS) algorithm. Unlike the Modified Ant Search (MAS) technique where ants unanimously moved between the exploration and exploitation phases, in the proposed algorithm, each ant is free to travel between the two aforementioned phases independent of other ants and as governed by its own pheromone intensity level. Moreover, sensitivity analysis is conducted on the design parameters to determine their corresponding neighborhood search boundaries and thus improve the search while in the exploitation mode. These implemented changes demonstrated a remarkable impact on the optimum synthesis of mechanisms for path generation tasks. A briefing of the MAS based algorithm is first presented after which the proposed modified optimization technique and its implementation on four-bar mechanisms are furnished. Finally, three case studies are conducted to evaluate the efficiency and robustness of the proposed methodology where the performances of the obtained optimum designs are benchmarked with those previously reported in literature.

A New Approach for Exact/Approximate Point Synthesis of Planar Mechanisms

2005 ◽  
Author(s):  
Ahmad Smaili ◽  
Nadim Diab
Keyword(s):  
Synthesis Method ◽  
Dimensional Synthesis ◽  
Gradient Search ◽  
Planar Mechanisms ◽  
Simple Method ◽  
New Approach ◽  
Optimum Synthesis ◽  
Approximate Synthesis ◽  
Optimum Solution ◽  
Synthesis Approach

The aim of this article is to provide a simple method to solve the mixed exact-approximate dimensional synthesis problem of planar mechanism. The method results in a mechanism that can traverse a closed path with the choice of any number of exact points while the rest are approximate points. The algorithm is based on optimum synthesis rather than on precision position methods. Ant-gradient search is applied on an objective function based on log10 of the error between the desired positions and those generated by the optimum solution. The log10 function discriminates on the side of generating miniscule errors (on the order of 10−14) at the exact points while allowing for higher errors at the approximate positions. The algorithm is tested by way of five examples. One of these examples was used to test exact/approximate synthesis method based on precision point synthesis approach.

Exact-Gradient Optimization Method for Rigid-Body Guidance Synthesis of Planar Mechanisms

2004 ◽  
Author(s):  
Ramon Sancibrian ◽  
Pablo Garcia ◽  
Fernando Viadero ◽  
Alfonso Fernandez
Keyword(s):  
Rigid Body ◽  
Synthesis Method ◽  
Computational Cost ◽  
Optimal Solution ◽  
Optimization Method ◽  
Planar Mechanisms ◽  
Synthesis Conditions ◽  
Kinematic Chains ◽  
Gradient Optimization ◽  
Definition Of

In this paper an approximate kinematic synthesis method is presented with application to rigid-body guidance in planar multibody systems. The problem of finding the optimal dimensions in linkages with rigid-body guidance constraints has been widely studied. Many techniques have been developed and applied to numerous kinematic chains. However, some problems remain without appropriate solution, such as a large number of required poses or low computational cost. The proposed method uses exact-gradient determination to search for an optimal solution. The modelling of the mechanism uses fully Cartesian coordinates and is formulated by means of algebraic constraint equations. Furthermore, the formulation allows the use of a large number of prescribed poses giving high accuracy in the definition of synthesis conditions. Examples are included to illustrate the new approach to some synthesis specifications.

Optimal Synthesis of Mechanisms for Path Generation Using Refined Numerical Representation Based Model and AIS Based Searching Method

2004 ◽  
Vol 127 (4) ◽  
pp. 688-691 ◽  
Author(s):  
Yong Liu ◽  
Renbin Xiao
Keyword(s):  
Synthesis Method ◽  
Optimal Synthesis ◽  
Numerical Representation ◽  
Path Generation ◽  
Artificial Immune ◽  
Planar Mechanisms ◽  
Artificial Immune Network ◽  
Synthesis Of Mechanisms ◽  
Initial Sampling ◽  
Searching Method

This paper presents an optimal synthesis method for path generation of planar mechanisms, in which a new path-description method named refined numerical representation is proposed to define the object function of the optimization model for path generation, and then the artificial immune network searching method is introduced to search candidate solutions. As a result, desired mechanisms can be generated independent of the scale, rotation, and translation transformation as well as sampling uniformity of initial sampling points. Experiment results demonstrate the effectiveness of the approach.

Synthesis of Gear-Linkage Mechanisms by Topology Optimization

2018 ◽  
Author(s):  
Neung Hwan Yim ◽  
Seok Won Kang ◽  
Yoon Young Kim
Keyword(s):  
Topology Optimization ◽  
Design Space ◽  
Synthesis Method ◽  
Variable Stiffness ◽  
Optimization Methods ◽  
Optimization Method ◽  
Planar Mechanisms ◽  
Gear Design ◽  
Linkage Design ◽  
Gradient Based

This work is concerned with a new mechanism synthesis method for the simultaneous determination of the type, number and dimension of mechanisms by topology optimization. Earlier topology optimization methods can synthesize linkage mechanisms that consist only of links and joints. The proposed synthesis method is a gradient-based topology optimization method useful for the synthesis of planar mechanisms consisting of linkages and gears. To formulate the topology optimization based method, we propose two superposed design spaces as a ground structure: the linkage and gear design spaces. The gear design space is discretized by newly proposed gear blocks while the linkage design space by rigid blocks. The zero-length springs with variable stiffness are used to control the connectivity of blocks, which in turns determines the configuration of the synthesized mechanism. After the proposed topology-optimization-based synthesis formulation is presented, its effectiveness and validity are checked with various synthesis examples.

Path Generation of Mechanism Based on Multimodal Optimization Using an Evolutionary Approach

2004 ◽  
Author(s):  
Renbin Xiao ◽  
Yong Liu ◽  
Gang Dou
Keyword(s):  
Optimization Algorithm ◽  
Optimization Method ◽  
Synthesis Methods ◽  
Immune Network ◽  
Path Generation ◽  
Multimodal Optimization ◽  
Artificial Immune ◽  
Planar Mechanisms ◽  
Artificial Immune Network ◽  
Performance Of Algorithm

This paper presents an optimization method for path generation of planar mechanisms by using artificial immune network based multimodal optimization algorithm. Firstly, the multimodal character of optimal synthesis methods for mechanism path generation is analyzed. Secondly, based on brief introduction of the artificial immune network theory and the AINET based multimodal optimization algorithm Opt-aiNet, the Opt-aiNet algorithm is improved in stopping criterion and parameter selection, which is ground on detailed analysis of the influence of parameters on the performance of algorithm. Then the improved Opt-aiNet algorithm is introduced to solve multimodal model of mechanism path generation. Finally, based upon the case study, the advantages of the improved Opt-aiNet algorithm in solving mechanism path generation problm are discussed and some concluding remarks are drawn.

Evolutionary Based Optimal Synthesis of Four-Bar Mechanisms

2003 ◽  
Author(s):  
D. Koladiya ◽  
P. S. Shiakolas ◽  
J. Kebrle
Keyword(s):  
Optimization Techniques ◽  
Optimization Approach ◽  
Path Generation ◽  
Planar Mechanisms ◽  
Function Generation ◽  
Novel Technique ◽  
Optimum Synthesis ◽  
Design Variables ◽  
Accuracy Level ◽  
And Function

Graphical and analytical syntheses have been well applied to path, motion and function generation of planar mechanisms. Optimization techniques in common, require “good initial guesses” and do not necessarily converge to a solution. This paper presents a methodology to synthesize mechanisms employing an evolutionary optimization approach technique known as Differential Evolution. The initial bounds for the design variables are defined automatically using a newly developed and novel technique called the Geometric Centroid of Precision Points. Optimum synthesis of four-bar linkages for path generation with user defined accuracy level at required precision points is discussed.

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

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