Optimization Design of a Walkable Fixture Mechanism

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Xiao-Jin Wan ◽  
Hanjie Zhang
Keyword(s):  
Performance Optimization ◽  
Error Propagation ◽  
Optimization Design ◽  
Large Scale ◽  
Optimization Problems ◽  
Optimization Procedure ◽  
Singular Values ◽  
Legged Robot ◽  
Nsga Ii ◽  
Propagation Matrix

In this paper, a novel fixture mechanism with combining a mobility of the legged robot and advantages of parallel mechanism is designed to hold the different size and shape, large-scale workpiece. The proposed mobile fixture mechanism holds the workpiece as a parallel manipulator while it walks as a legged robot. This kind of robotized fixtures can possess high self-configurable ability to accommodate a wider variety of products. In order to obtain the best kinematic dexterity and accuracy characteristics, comprehensive performance optimization is performed by non-dominated-genetic algorithm (NSGA-II). In the optimization procedure, a conventional kinematic transformation matrix (Jacobian matrix) and error propagation matrix are obtained through derivation and differential motion operations. The singular values and condition number based on velocity Jacobians and error amplification factors based on error propagation matrix are derived; in addition, relative pose error range of end effector is also derived. On the basis of the above measure indices, three kinds of nonlinear optimization problems are defined to obtain the optimal architecture parameters for better kinematic accuracy and dexterity in workspace. Comparison analyses of the optimized results are performed.

scholarly journals Distribution Endpoint Estimation Assessment for the use in Metaheuristic Optimization Procedure

MENDEL ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 93-100
Author(s):  
Jan Holesovky
Keyword(s):  
Extreme Value Theory ◽  
Large Scale ◽  
Optimization Problems ◽  
Random Search ◽  
Optimization Procedure ◽  
Short Review ◽  
Value Theory ◽  
Extreme Value ◽  
Mixed Integer ◽  
Endpoint Estimation

Metaheuristic algorithms are often applied to numerous optimization problems, involving large-scale and mixed-integer instances, specifically. In this contribution we discuss some refinements from the extreme value theory to the lately proposed modification of partition-based random search. The partition-based approach performs iterative random sampling at given feasible subspaces in order to exclude the less favourable regions. The quality of particular regions is evaluated according to the promising index of a region. From statistical perspective, determining the promising index is equivalent to the endpoint estimation of a probability distribution induced by the objective function at the sampling subspace. In the following paper, we give a short review of the recent endpoint estimators derived on the basis of extreme value theory, and compare them by simulations. We discuss also the difficulties in their application and suitability of the estimators for various optimization instances.

A Two-Stage Optimization Procedure for the Design of an EAP-Actuated Soft Gripper

2019 ◽  
Author(s):  
Wei Zhang ◽  
Jonathan Hong ◽  
Saad Ahmed ◽  
Zoubeida Ounaies ◽  
Mary Frecker
Keyword(s):  
Design Optimization ◽  
Compliant Mechanisms ◽  
Optimization Problems ◽  
Beam Theory ◽  
Optimization Procedure ◽  
Analytical Models ◽  
Euler Beam ◽  
Two Stage ◽  
Nsga Ii ◽  
Wide Range

Abstract An increasing range of engineering applications require soft grippers, which use compliant mechanisms instead of stiff components to achieve grasping action, have high conformability and exert gentle contact with target objects compared to traditional grippers. In this study, a three-fingered gripper is first designed based on a notched self-folding mechanism actuated using an electrostrictive PVDF-based terpolymer. Then the design optimization problem is formulated, where the design objectives are to maximize the free deflection Δfree and the blocked force Fb. A computationally efficient two-stage design optimization procedure is proposed and successfully applied in the gripper design. NSGA-II is adopted as the optimization algorithm for its capacity to deal with multi-objective optimization problems and to find the global optima with high design variables and large design domains. In stage one, computationally less expensive analytical models are developed based on Bernoulli-Euler beam theory and Castigliano’s theorem to calculate Δfree and Fb. Utility function is applied to determine the best design in the last generation of stage one. In stage two, 3D FEA models are developed, using the dimensions determined by the best design from stage one, to investigate effect of the shape of segment surfaces on the design objectives. Overall, the proposed two-stage optimization procedure is successfully applied in the actuator design and shows the potential to solve a wide range of structural optimization problems.

Evolutionary Metaheuristics to Solve Multiobjective Assignment Problem in Telecommunication Network

2020 ◽  
Vol 11 (2) ◽  
pp. 56-76
Author(s):  
Benkanoun Yazid ◽  
Bouroubi Sadek ◽  
Chaabane Djamal
Keyword(s):  
Evolutionary Algorithm ◽  
Large Scale ◽  
Optimization Problems ◽  
Choquet Integral ◽  
Telecommunication Network ◽  
Exact Algorithms ◽  
Nsga Ii ◽  
Pareto Optimal Set ◽  
System A ◽  
Integral Measure

The authors propose a computing approach for solving a multiobjective problem in the telecommunication network field, suggested by an Algerian industrial company. The principal goal is in developing a palliative solution to overcome some generated problems existing in the current management system. A mathematical operational model has been established. The exact algorithms that solve multiobjective optimization problems are not appropriate for large scale problems. However, the application of metaheuristics approach leads perfectly to approximate the Pareto optimal set. In this paper, the authors apply a well-known multiobjective evolutionary algorithm, the Non-dominated Sorting Genetic Algorithm (NSGA-II), compare the obtained results with those generated by the Strength Pareto Evolutionary Algorithm-II (SPEA2) and propose a way to help the decision maker, who is often confronted with the choice of a final solution, to make his preferences afterward using a utility function based on a Choquet integral measure. Finally, numerical experiments are presented to validate the approach.

OPTIMUM DESIGN OF SPACE FRAMES UNDER SEISMIC LOADING

2001 ◽  
Vol 01 (01) ◽  
pp. 105-123 ◽  
Author(s):  
MANOLIS PAPADRAKAKIS ◽  
NIKOS D. LAGAROS ◽  
VAGELIS PLEVRIS
Keyword(s):  
Structural Optimization ◽  
Optimum Design ◽  
Large Scale ◽  
Optimization Problems ◽  
Response Spectrum ◽  
Minimum Weight ◽  
Optimization Procedure ◽  
Seismic Loading ◽  
Approximate Design ◽  
Design Response Spectrum

The objective of this paper is to perform structural optimization under seismic loading. Combinatorial optimization methods and in particular algorithms based on Evolution Strategies are implemented for the solution of large-scale structural optimization problems under seismic loading. In this work the efficiency of a rigorous approach in treating dynamic loading is investigated and compared with a simplified dynamic analysis in the framework of finding the optimum design of structures with minimum weight. In this context a number of accelerograms are produced from the elastic design response spectrum of the region. These accelerograms constitute the multiple loading conditions under which the structures are optimally designed. This approach is compared with an approximate design approach based on simplifications adopted by the seismic codes. The results obtained for a characteristic test problem indicate a substantial improvement in the final design when the proposed optimization procedure is implemented.

Large Scale Plant Optimization Problems

1988 ◽  
Author(s):  
Paul Cronin ◽  
Harry Woerde ◽  
Rob Vasbinder
Keyword(s):  
Large Scale ◽  
Optimization Problems ◽  
Plant Optimization

Structure Sensitivity Analysis and Dynamic Performance Optimization of Marine Gearbox

2017 ◽  
Author(s):  
Tengjiao Lin ◽  
Daokun Xie ◽  
Ziran Tan ◽  
Bo Liu
Keyword(s):  
Sensitivity Analysis ◽  
Performance Optimization ◽  
Optimization Design ◽  
Dynamic Performance ◽  
Structure Sensitivity ◽  
Superposition Method ◽  
Structure Parameters ◽  
Analysis Model ◽  
Vibration Acceleration ◽  
Response Optimization

The aim of this paper is to investigate the influence of structure parameters on the vibration characteristics and improve the dynamic performance of marine gearbox. A finite element model was established to solve the dynamic response by using modal superposition method. Based on the theory of multi-objective optimization design, the structure sensitivity analysis model of marine gearbox was established, which takes the structure parameters of the housing as design variables. The modal and response sensitivity was obtained by using the optimal gradient method. According to the results of sensitivity analysis, a modal and response optimization model of marine gearbox was established. The objective was to avoid natural frequencies from the excitation frequencies and minimize the root mean square of vibration acceleration of the evaluating points on the surface of housing. Then the modal optimization and response optimization of gearbox were carried out by using zero-order and first-order optimization method. The results indicate that the dynamic optimization of the gearbox can be achieved. After optimization, the amplitude of vibration acceleration of the evaluating points on the housing surface has been reduced and the resonance of marine gearbox can be avoided.

scholarly journals A Practical Algorithm for General Large Scale Nonlinear Optimization Problems

1999 ◽  
Vol 9 (3) ◽  
pp. 755-778 ◽  
Author(s):  
Paul T. Boggs ◽  
Anthony J. Kearsley ◽  
Jon W. Tolle
Keyword(s):  
Nonlinear Optimization ◽  
Large Scale ◽  
Optimization Problems ◽  
Practical Algorithm
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