scholarly journals Construction and Layout of Coordinated Multirobots System Based on Parallel Thought

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Wanqiang Xi ◽  
Yaoyao Wang ◽  
Yadong Ding ◽  
Bai Chen
Keyword(s):  
Weight Ratio ◽  
Optimization Method ◽  
Parallel Robot ◽  
Layout Optimization ◽  
Type Synthesis ◽  
Layout Problem ◽  
Bee Colony ◽  
Operational Rule ◽  
Branched Chain ◽  
Definition Of

Aiming at the problems that are the construction and the layout optimization of the coordinated multirobots system, the concept of an equivalent parallel robot (EPR) is proposed based on parallel thought in this paper. That is, each robot is regarded as a branched chain of the EPR in coordination. Thus, it can be converted into the problem for the type synthesis and the layout of the parallel robot. Firstly, the definition of robotic characteristic (C) set and the corresponding operational rule are given. Then, the minimum occupied area, cycle time, and condition number are used as the optimized objectives. The weight ratio is used to express the importance of the three objectives to meet the requirements of different scenes. Afterwards, based on the theory of C set, the three translational (3T) operational requirements that can be extended to other degree of freedom (DOF) are analyzed. Finally, the feasibility of the proposed methods is verified by the DOF analysis and simulation experiment. Moreover, the multiobjective layout problem is optimized based on the artificial bee colony (ABC) algorithm. The results show that the constructed robot combinations and the layout optimization method are satisfactory.

Type synthesis of coordinated multi-robot system based on parallel thought

2018 ◽  
Vol 42 (2) ◽  
pp. 164-176 ◽  
Author(s):  
Wanqiang Xi ◽  
Bai Chen ◽  
Yaoyao Wang ◽  
Feng Ju
Keyword(s):  
Degrees Of Freedom ◽  
Screw Theory ◽  
Parallel Robot ◽  
Parallel Robots ◽  
Type Synthesis ◽  
World Coordinate System ◽  
Coordination System ◽  
Branched Chain ◽  
Branched Chains ◽  
Multi Robot

For the synthesis of the required type about the multi-robot coordination system in industrial transportation, this paper presents a novel method in which each robot in the coordinated task is viewed as a branched chain of an equivalent parallel robot (EPR), which is converted into a problem for type synthesis of parallel robots. A theoretic method is proposed to represent the kinematic features of the mechanism’s end-effector and its position and pose in the world coordinate system. The basic concept of a robotic characteristic (C) set is given, and the corresponding algorithm is analyzed. Based on the theory of C set, the concrete steps for type synthesis of EPR are presented by analyzing the characteristics of its branched chains, and many EPR groups with end kinematic features for the C sets of the operational tasks are obtained. Then three translational (3T) operational requirements that can be extended to other degrees of freedom (DOF) are adopted, and the DOF of homogeneous and heterogeneous EPR are analyzed using screw theory. Finally the validation of the method is demonstrated by Adams, which shows that the two groups are able to complete the task.

Applications of Multiple Objective Genetic Algorithms in the Optimization Design of Tracked Self-Moving Power’s Layout

2013 ◽  
Vol 307 ◽  
pp. 161-165
Author(s):  
Hai Jin ◽  
Jin Fa Xie
Keyword(s):  
Optimization Design ◽  
Pareto Front ◽  
Layout Optimization ◽  
Multiple Objective ◽  
Multi Objective Optimization ◽  
Layout Problem ◽  
Basic Principles ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Set Up

A multi-objective genetic algorithm is applied into the layout optimization of tracked self-moving power. The layout optimization mathematical model was set up. Then introduced the basic principles of NSGA-Ⅱ, which is a Pareto multi-objective optimization algorithm. Finally, NSGA-Ⅱwas presented to solve the layout problem. The algorithm was proved to be effective by some practical examples. The results showed that the algorithm can spread toward the whole Pareto front, and provide many reasonable solutions once for all.

UNCERTAINTY BASED ROBUST OPTIMIZATION IN AERODYNAMICS

2009 ◽  
Vol 23 (03) ◽  
pp. 477-480 ◽  
Author(s):  
ZHILI TANG
Keyword(s):  
Nash Equilibrium ◽  
Robust Design ◽  
Single Point ◽  
Optimization Method ◽  
Equilibrium Solutions ◽  
Design Problems ◽  
Nash Equilibrium Solutions ◽  
Definition Of ◽  
Taguchi Robust Design ◽  
Statistical Definition

The Taguchi robust design concept is combined with the multi-objective deterministic optimization method to overcome single point design problems in Aerodynamics. Starting from a statistical definition of stability, the method finds, Nash equilibrium solutions for performance and its stability simultaneously.

Generative Optimization for Automatic Creation of 3D CAD Platforms

2021 ◽  
Author(s):  
William F. Quintero-Restrepo ◽  
Brian K. Smith ◽  
Junfeng Ma
Keyword(s):  
Evolutionary Algorithms ◽  
Six Sigma ◽  
Design Space ◽  
Optimization Method ◽  
Efficiency Improvement ◽  
3D Cad ◽  
Systems Model ◽  
Electric Machinery ◽  
Definition Of ◽  
Six Sigma Approach

Abstract The efficient creation of 3D CAD platforms can be achieved by the optimization of their design process. The research presented in this article showcases a method for allowing such efficiency improvement. The method is based on the DMADV six sigma approach. During the Define step, the definition of the scope and design space is established. In the Measure step, the initial evaluation of the platforms to be improved is done with the help of a Metrics framework for 3D CAD platforms. The Analyze Step includes the identification and optimization of the systems’ model of the process based on the architecture and the multiple objectives required for the improvement. The optimization method used that is based on evolutionary algorithms allows for the identification of the best improvement alternatives for the next step. During Design step of the method, the improvement alternatives are planned and executed. In the final Verification step, the evaluation of the improved process is tested against the previous status with the help of the Metrics Framework for 3D CAD platforms. The method is explained with an example case of a 3D CAD platform for creating metallic boxes for electric machinery.

scholarly journals Parallel Robot Translational Performance Evaluation through Direction-Selective Index (DSI)

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
G. Boschetti ◽  
R. Rosa ◽  
A. Trevisani
Keyword(s):  
Performance Evaluation ◽  
Performance Index ◽  
General Framework ◽  
Dynamic Performance ◽  
Parallel Manipulators ◽  
Parallel Robot ◽  
Performance Indexes ◽  
Definition Of ◽  
Performance Variations

Performance indexes usually provide global evaluations of robot performances mixing their translational and/or rotational capabilities. This paper proposes a definition of performance index, called direction-selective index (DSI), which has been specifically developed for parallel manipulators and can provide uncoupled evaluations of robot translational capabilities along relevant directions. The DSI formulation is first presented within a general framework, highlighting its relationship with traditional manipulability definitions, and then applied to a family of parallel manipulators (4-RUU) of industrial interest. The investigation is both numerical and experimental and allows highlighting the two chief advantages of the proposed DSIs over more conventional manipulability indexes: not only are DSIs more accurate in predicting the workspace regions where manipulators can best perform translational movements along specific directions, but also they allow foreseeing satisfactorily the dynamic performance variations within the workspace, though being purely kinematic indexes. The experiments have been carried out on an instrumented 4-RUU commercial robot.

IMPERFECT COORDINATION IN OPTIMIZATION

2009 ◽  
Vol 20 (04) ◽  
pp. 527-538 ◽  
Author(s):  
ELENA RAMÍREZ BARRIOS ◽  
JUAN G. DÍAZ OCHOA
Keyword(s):  
Control Function ◽  
Optimization Method ◽  
Free Lattice ◽  
Conventional Methods ◽  
Definition Of

We present a novel optimization method for an Ising like system suspended in a lattice with nonstatic defects. Depending on the size of the experimental probe the system spontaneously defines a defect free lattice where the control function can be optimized using conventional methods as Metropolis heuristics. We illustrate this method in a lattice with variable defects and show how the magnetization of the system depends on the spontaneous definition of the defect-free lattice. This approximation should be useful as a basis for the definition of systems of agents with imperfect coordination.

scholarly journals Consensus Definition of Fetal Growth Restriction in Intrauterine Fetal Death: A Delphi Procedure

2020 ◽  
Author(s):  
Irene Maria Beune ◽  
Stefanie Elisabeth Damhuis ◽  
Wessel Ganzevoort ◽  
John Ciaran Hutchinson ◽  
Teck Yee Khong ◽  
...  
Keyword(s):  
Birth Weight ◽  
Fetal Growth ◽  
Fetal Growth Restriction ◽  
Fetal Death ◽  
Weight Ratio ◽  
Liver Weight ◽  
Growth Restriction ◽  
Intrauterine Fetal Death ◽  
Consensus Definition ◽  
Definition Of

Context.— Fetal growth restriction is a risk factor for intrauterine fetal death. Currently, definitions of fetal growth restriction in stillborn are heterogeneous. Objectives.— To develop a consensus definition for fetal growth restriction retrospectively diagnosed at fetal autopsy in intrauterine fetal death. Design.— A modified online Delphi survey in an international panel of experts in perinatal pathology, with feedback at group level and exclusion of nonresponders. The survey scoped all possible variables with an open question. Variables suggested by 2 or more experts were scored on a 5-point Likert scale. In subsequent rounds, inclusion of variables and thresholds were determined with a 70% level of agreement. In the final rounds, participants selected the consensus algorithm. Results.— Fifty-two experts participated in the first round; 88% (46 of 52) completed all rounds. The consensus definition included antenatal clinical diagnosis of fetal growth restriction OR a birth weight lower than third percentile OR at least 5 of 10 contributory variables (risk factors in the clinical antenatal history: birth weight lower than 10th percentile, body weight at time of autopsy lower than 10th percentile, brain weight lower than 10th percentile, foot length lower than 10th percentile, liver weight lower than 10th percentile, placental weight lower than 10th percentile, brain weight to liver weight ratio higher than 4, placental weight to birth weight ratio higher than 90th percentile, histologic or gross features of placental insufficiency/malperfusion). There was no consensus on some aspects, including how to correct for interval between fetal death and delivery. Conclusions.— A consensus-based definition of fetal growth restriction in fetal death was determined with utility to improve management and outcomes of subsequent pregnancies.

Identification of Forming Limits for Unidirectional Carbon Textiles in Reality and Mesoscopic Simulation

2013 ◽  
Vol 554-557 ◽  
pp. 423-432 ◽  
Author(s):  
Patrick Böhler ◽  
Frank Härtel ◽  
Peter Middendorf
Keyword(s):  
Raw Materials ◽  
Weight Ratio ◽  
Experimental Tests ◽  
Simulation Method ◽  
Failure Criteria ◽  
Forming Process ◽  
Mesoscopic Simulation ◽  
Sewing Thread ◽  
Young’S Moduli ◽  
Definition Of

In several fields of engineering the use of carbon fibre reinforced material (CFRP) is increasing. Minimized weight due to CFRPs could lead to lower consumption of raw materials especially in the automotive area. The goal within the research project TC² is the decrease of costs and production time for composite materials. To achieve better performance to weight ratio and to get acceptable production conditions the draping of dry unidirectional textiles and a following RTM process is investigated. Due to the high degree of complexity of automotive structures the forming process is challenging. Gapping in the textile could appear at corners as well as wrinkling or flexion of the fibres. To be able to define the amount and direction of layers or patches it is necessary to know the limits of forming for unidirectional material and to be able to predict the behaviour of the textile during the forming process. For the definition of the process limits several draping strategies are performed on different corner blend geometries. The goal of that work is to define the critical gradient of the flange to get first failures such as wrinkling or gapping. It is also important to understand the influence of different draping strategies. Parallel to the experimental tests a mesoscopic simulation method using an approach with roving and sewing thread is developed and presented. It is able to predict the material behaviour in critical areas (gapping, wrinkling). Different Young’s moduli and failure criteria can be implemented for the two main directions as well as for the bending of the textile. A validation with the experimental results is performed with the aim to enable the prediction of the textile behaviour using simulation methods.

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