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.

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.

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.

scholarly journals Design of Non-Anthropomorphic Robotic Hands for Anthropomorphic Tasks

2011 ◽  
Author(s):  
Edgar Simo-Serra ◽  
Francesc Moreno-Noguer ◽  
Alba Perez-Gracia
Keyword(s):  
Genetic Algorithm ◽  
Solution Space ◽  
Kinematic Chain ◽  
Human Hand ◽  
Dimensional Synthesis ◽  
Robotic Hands ◽  
Serial Chain ◽  
Finite Set ◽  
Numerical Solver ◽  
Local Optimizer

In this paper, we explore the idea of designing non-anthropomorphic multi-fingered robotic hands for tasks that replicate the motion of the human hand. Taking as input data a finite set of rigid-body positions for the five fingertips, we develop a method to perform dimensional synthesis for a kinematic chain with a tree structure, with five branches that share three common joints. We state the forward kinematics equations of relative displacements for each serial chain expressed as dual quaternions, and solve for up to five chains simultaneously to reach a number of positions along the hand trajectory. This is done using a hybrid global numerical solver that integrates a genetic algorithm and a Levenberg-Marquardt local optimizer. Although the number of candidate solutions in this problem is very high, the use of the genetic algorithm allows us to perform an exhaustive exploration of the solution space to obtain a set of solutions. We can then choose some of the solutions based on the specific task to perform. Note that these designs match the task exactly while generally having a finger design radically different from that of the human hand.

scholarly journals Hybrid Seven-bar Press Mechanism

2018 ◽  
Vol 12 (3) ◽  
pp. 181-187
Author(s):  
M. Erkan Kütük ◽  
L. Canan Dülger
Keyword(s):  
Genetic Algorithm ◽  
Objective Function ◽  
Design Optimization ◽  
Hybrid System ◽  
Degrees Of Freedom ◽  
Dimensional Synthesis ◽  
Design Variables ◽  
Optimization Study ◽  
Metal Stamping

An optimization study with kinetostatic analysis is performed on hybrid seven-bar press mechanism. This study is based on previous studies performed on planar hybrid seven-bar linkage. Dimensional synthesis is performed, and optimum link lengths for the mechanism are found. Optimization study is performed by using genetic algorithm (GA). Genetic Algorithm Toolbox is used with Optimization Toolbox in MATLAB®. The design variables and the constraints are used during design optimization. The objective function is determined and eight precision points are used. A seven-bar linkage system with two degrees of freedom is chosen as an example. Metal stamping operation with a dwell is taken as the case study. Having completed optimization, the kinetostatic analysis is performed. All forces on the links and the crank torques are calculated on the hybrid system with the optimized link lengths

scholarly journals Hybrid Optimization Based Mathematical Procedure for Dimensional Synthesis of Slider-Crank Linkage

Mathematics ◽  
2021 ◽  
Vol 9 (13) ◽  
pp. 1581
Author(s):  
Alfonso Hernández ◽  
Aitor Muñoyerro ◽  
Mónica Urízar ◽  
Enrique Amezua
Keyword(s):  
Genetic Algorithm ◽  
Fitness Function ◽  
Linear Equations ◽  
Optimization Procedure ◽  
Optimization Techniques ◽  
Dimensional Synthesis ◽  
Hybrid Strategy ◽  
Dimensional Parameters ◽  
Optimization Methodology ◽  
Crank Mechanism

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.

scholarly journals Towards a multi-criteria framework for stereotomy – Workflows for subtractive fabrication in complex geometries

2018 ◽  
Vol 6 (3) ◽  
pp. 468-478 ◽  
Author(s):  
Shayani Fernando ◽  
Simon Weir ◽  
Dagmar Reinhardt ◽  
Adam Hannouch
Keyword(s):  
Case Studies ◽  
Research Work ◽  
Structural Performance ◽  
Future Research ◽  
Advanced Manufacturing ◽  
Essential Condition ◽  
Robotic Fabrication ◽  
Research Findings ◽  
Comparative Case Studies ◽  
End Effectors

Abstract In a context of stereotomy, robotic subtractive cutting enables design-to-production processes that integrate craftsmanship with advanced manufacturing technology. This paper discusses empirical research into the fabrication of complex and custom-designed geometries by means of robotic subtractive cutting, with a specific focus on modular elements and joint typologies that form an essential condition for self-supporting stone structures. The paper presents research findings in two parts. In the first part, four case studies for jointing techniques and a cross-comparison between these are introduced to derive strategies for multiple criteria, including macro-and-micro geometries, modules and joints, structural performance, material variations, machine cutting methods and end-effectors, and robotic workspace. In the second part, the paper focuses on the structural performance of the joint geometry typologies, expanded towards material constraints and robotic fabrication process. The paper concludes with a discussion on these varied subtractive cutting methodologies and a resulting design-to-fabrication workflow, and indicates future research work. Highlights Demonstrates applications of stereotomic practice for robotic subtractive cutting. Reports on comparative case studies for four different module and joint structures. Discusses structural performance for Interlocking base block geometries. Provides a multi-criteria framework for structural, material/machine cutting methods. Develops a design-to-fabrication workflow in robotic subtractive cutting.

Optimum Synthesis of Rigid Mechanisms Using Real Coded Quantum-Inspired Evolution Algorithm (RQIEA) With Neighborhood Search

2007 ◽  
Author(s):  
Ahmad Smaili ◽  
Mazen Hassanieh ◽  
Bachir Chaaya ◽  
Fawzan Al Fares
Keyword(s):  
Quantum Computing ◽  
Search Algorithm ◽  
Random Search ◽  
Quantum Gates ◽  
Neighborhood Search ◽  
Gradient Search ◽  
Quantum Bits ◽  
Optimum Synthesis ◽  
Evolution Algorithm ◽  
Optimization Schemes

A modified real coded quantum-inspired evolution algorithm (MRQIEA) is herein presented for optimum synthesis of planar rigid body mechanisms (RBMs). The MRQIEA employs elements of quantum computing such as quantum bits, registers, and quantum gates, neighborhood search engine, and gradient search to form a random search algorithm for solution optimization of a wide class of problems. A brief overview of the quantum computing elements and their adaptation to the optimization algorithm is first presented. The algorithm is then adapted to the synthesis problem of RBMs. Finally, the algorithm is demonstrated and compared to other search methods by way of three examples, including two benchmark examples that have been used in the literature to assess the performance of other optimization schemes.

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