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.

A Triad-Based Two-DOF Robomech: Architecture and Optimum Synthesis

2005 ◽  
Author(s):  
Ahmad Smaili ◽  
Bachir Chaaya
Keyword(s):  
Genetic Algorithm ◽  
Case Studies ◽  
Kinematic Chain ◽  
Dimensional Synthesis ◽  
Gradient Search ◽  
Search Methods ◽  
Optimum Synthesis ◽  
End Effectors

Presented in this paper is a 2-dof robomech that carries two end effectors to perform two functions simultaneously. The robomech has a 7R architecture consisting of two triad wings connected to form two cells. The over-constrained kinematic chain cannot traverse continuous trajectories but may be synthesized to move the end effectors through a set of desired locations. The article presents the architecture of the proposed robomech, establishes its kinematic relations and constraints, and provides dimensional synthesis scheme based on genetic algorithm and gradient search methods. Two case studies are included to demonstrate the applicability of the proposed robomech.

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.

Automated Synthesis of Planar Mechanisms With Revolute, Prismatic and Pin-in-Slot Joints

2015 ◽  
Author(s):  
Weifeng Huang ◽  
Matthew I. Campbell
Keyword(s):  
Synthesis Method ◽  
Automated Synthesis ◽  
Planar Mechanisms ◽  
Revolute Joint ◽  
Synthesis Approach

This paper presents a graph synthesis approach to planar N-bar mechanisms with revolute (R), prismatic (P), and RP (pin-in-slot) joints. This novel graph synthesis method extends the enumeration to define the possible topologies for mechanisms with any mix of R-, P-, and RP-joints. Each topology is explicitly defined as a graph which can be viewed and simulated within an online kinematic simulator. This method successfully produces the same number of topologies for 6, 8, 10, and 12-bar revolute joint mechanisms as those shown in the existing literature. It explicitly calculates all topologies for 6, 8, and 10 bars with a mix of the three joint-types.

A New Approach to Shape Optimization for Closed Path Synthesis of Planar Mechanisms

2005 ◽  
Vol 129 (9) ◽  
pp. 941-948 ◽  
Author(s):  
Ahmad Smaili ◽  
Nadim Diab
Keyword(s):  
Shape Optimization ◽  
Fourier Descriptors ◽  
Angular Deviation ◽  
Mathematical Approach ◽  
Closed Path ◽  
Planar Mechanisms ◽  
Simple Method ◽  
New Approach ◽  
Starting Point ◽  
Path Synthesis

A method for the synthesis of four-bar mechanisms to generate closed paths through shape optimization is herein introduced. The objective function is not based on Fourier descriptors, but rather on the cyclic angular deviation (CAD) vector associated with a set of desired points on the curve. A simple method is introduced to account for the starting point shift between the desired CAD and the generated one. Following shape optimization, a simple mathematical approach is devised to properly scale, rotate, and translate the mechanism to the desired configuration. Two case studies are presented to demonstrate the effectiveness and robustness of the proposed method.

Stackable 5R Chains With Multiple End-Effectors: Architecture and Optimum Synthesis

2006 ◽  
Author(s):  
Ahmad Smaili ◽  
Bachir Chaaya
Keyword(s):  
Genetic Algorithm ◽  
Spot Welding ◽  
Dimensional Synthesis ◽  
Gradient Search ◽  
Search Methods ◽  
Optimum Synthesis ◽  
Welding Operation ◽  
End Effectors

Presented in this paper is a 4-dof robomech consisting of a stack of two five-bar (5R) chains with multiple end effectors to perform two distinct yet coordinated tasks simultaneously. The over-constrained kinematics chain cannot traverse continuous trajectories but may be synthesized to move the end effectors through a set of desired locations. The article elaborates on the architecture of the proposed robomech, establishes its kinematics relations and constraints, and provides dimensional synthesis scheme based on genetic algorithm and gradient search methods. A case study featuring the robomech performing spot welding operation along two distinct trajectories is included to demonstrate the applicability of the proposed robomech.

Mixed Exact-Approximate Position Synthesis of Planar Mechanisms

1998 ◽  
Vol 122 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Jennifer E. Holte ◽  
Thomas R. Chase ◽  
Arthur G. Erdman
Keyword(s):  
Three Dimensional ◽  
Solution Space ◽  
Motion Generation ◽  
Planar Mechanisms ◽  
Dimensional Solution ◽  
New Approach ◽  
Fuzzy Constraints ◽  
Position Synthesis ◽  
Synthesis Approach ◽  
Exact Positions

A new approach to the synthesis of planar linkage mechanisms with fuzzy constraints is proposed. Design methods for two exact positions and an unlimited number of approximate positions are presented. The use of approximate specifications allows the designer to represent design objectives more realistically. A precision position synthesis approach is used to generate a three-dimensional solution space of dyads satisfying all exact and approximate constraints. The three-dimensional solution space is reduced to a two-dimensional ground-pivot map. Computer implementation of the proposed methodologies would allow designers with little or no knowledge of the synthesis techniques to interactively explore maps of solutions for four-bar motion generation. [S1050-0472(00)00803-5]

Optimum Synthesis of Mechanisms Using Tabu-Gradient Search Algorithm

2004 ◽  
Vol 127 (5) ◽  
pp. 917-923 ◽  
Author(s):  
Ahmad A. Smaili ◽  
Nadim A. Diab ◽  
Naji A. Atallah
Keyword(s):  
Tabu Search ◽  
Short Term Memory ◽  
Search Algorithm ◽  
Gradient Algorithm ◽  
Gradient Search ◽  
Planar Mechanisms ◽  
Optimum Synthesis ◽  
Synthesis Of Mechanisms ◽  
Tabu Search Method ◽  
Optimization Schemes

A tabu-gradient search is herein presented for optimum synthesis of planar mechanisms. The solution generated by a recency-based, short term memory tabu search is used to start a gradient search to drive the solution ever closer to the global minimum. A brief overview of the tabu-search method is first presented. A tabu-gradient algorithm is then used to synthesize four-bar mechanisms for path generation tasks by way of three examples, including two benchmark examples used before to test other deterministic and intelligent optimization schemes. Compared with the corresponding results generated by other schemes, the tabu-gradient search rendered the most optimal solutions of all.

On nonassembly in the optimal dimensional synthesis of planar mechanisms

2001 ◽  
Vol 21 (5) ◽  
pp. 345-354 ◽  
Author(s):  
R.J. Minnaar ◽  
D.A. Tortorelli ◽  
J.A. Snyman
Keyword(s):  
Dimensional Synthesis ◽  
Planar Mechanisms

Optimization of Green Synthesis Approach of Silver Nanoparticles Using Indonesian Wild Honey

2021 ◽  
Vol 891 ◽  
pp. 111-115
Author(s):  
Maradhana Agung Marsudi ◽  
Farah Fitria Sari ◽  
Pandu Mauliddin Wicaksono ◽  
Adinda Asmoro ◽  
Arif Basuki ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Particle Count ◽  
Transmission Electron ◽  
Nitrate Precursor ◽  
Synthesis Approach

In this work, silver nanoparticles have been successfully synthesized using simple and environmentally friendly ‘green synthesis’ method using Indonesian wild honey as mediator. Particle count and size can be optimized by varying the silver nitrate precursor and honey concentration, with the help of sodium hydroxide as pH regulator. Based on X-ray diffraction (XRD) result, crystalline structure of Ag has been confirmed in sample with impurities from AgCl. Based on dynamic light scattering (DLS) and transmission electron microscopy (TEM) results, it was found that the smallest average particles size of AgNPs (117.5 nm from DLS and 11.1 nm from TEM) was obtained at sample with 5% w/v of honey and 0.5 mM of AgNO3.

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