Multi-Criteria Optimal Design of Parallel Manipulators Based on Natural Frequency

2010 ◽  
Vol 29-32 ◽  
pp. 2435-2442 ◽  
Author(s):  
Bang Jun Lv ◽  
S.J. Zhu ◽  
J.F. Xing
Keyword(s):  
Optimal Design ◽  
Natural Frequency ◽  
Parallel Manipulators ◽  
Average Frequency ◽  
Pareto Optimal Set ◽  
Large Size ◽  
Matrix Condition Number ◽  
Dimensionally Homogeneous Jacobian Matrix ◽  
Matrix Condition ◽  
Optimal Set

The Stewart manipulator has characteristics of low natural frequency, high cost and large size which make it difficult to obtain optimum performance with high dynamic response. The lowest natural frequency in the total workspace and average of six frequencies at home configuration of Stewart manipulator are introduced as indices to evaluate dynamic stability. Multi-criteria optimal design based on genetic algorithm (GA) was presented synthetically considering the workspace requirement, lowest natural frequency, average frequency and global dimensionally homogeneous Jacobian matrix condition number. An optimal result was obtained through standard GA using penalty function and the Pareto-optimal set was also obtained through parallel selection method.

Multi-objective optimal design of a novel 6-DOF spray-painting robot

Robotica ◽  
2021 ◽  
pp. 1-15
Author(s):  
Jun Wu ◽  
Xiaojian Wang ◽  
Binbin Zhang ◽  
Tian Huang
Keyword(s):  
Optimal Design ◽  
Performance Index ◽  
Virtual Work ◽  
Kinematic Model ◽  
Spray Painting ◽  
Virtual Work Principle ◽  
Multi Objective ◽  
Pareto Optimal Set ◽  
Painting Robot ◽  
Optimal Set

Abstract This paper deals with the multi-objective optimal design of a novel 6-degree of freedom (DOF) hybrid spray-painting robot. Its kinematic model is obtained by dividing it into serial and parallel parts. The dynamic equation is formulated by virtual work principle. A performance index for evaluating the compactness of robot is presented. Taking compactness, motion/force transmissibility, and energy consumption as performance indices, the optimal geometric parameters of the robot are selected in the Pareto-optimal set by constructing a comprehensive performance index. This paper is very useful for the development of the spray-painting robot.

Optimal design of 6-DOF eclipse mechanism based on task-oriented workspace

Robotica ◽  
2011 ◽  
Vol 30 (7) ◽  
pp. 1041-1048 ◽  
Author(s):  
Donghun Lee ◽  
Jongwon Kim ◽  
TaeWon Seo
Keyword(s):  
Optimal Design ◽  
Unit Length ◽  
Numerical Procedure ◽  
Design Procedure ◽  
Mass Reduction ◽  
Objective Functions ◽  
Design Efficiency ◽  
Task Oriented ◽  
Structural Mass ◽  
Optimal Set

SUMMARYWe present a new numerical optimal design for a redundant parallel manipulator, the eclipse, which has a geometrically symmetric workspace shape. We simultaneously consider the structural mass and design efficiency as objective functions to maximize the mass reduction and minimize the loss of design efficiency. The task-oriented workspace (TOW) and its partial workspace (PW) are considered in efficiently obtaining an optimal design by excluding useless orientations of the end-effector and by including just one cross-sectional area of the TOW. The proposed numerical procedure is composed of coarse and fine search steps. In the coarse search step, we find the feasible parameter regions (FPR) in which the set of parameters only satisfy the marginal constraints. In the fine search step, we consider the multiobjective function in the FPR to find the optimal set of parameters. In this step, fine search will be kept until it reaches the optimal set of parameters that minimize the proposed objective functions by continuously updating the PW in every iteration. By applying the proposed approach to an eclipse-rapid prototyping machine, the structural mass of the machine can be reduced by 8.79% while the design efficiency is increased by 6.2%. This can be physically interpreted as a mass reduction of 49 kg (the initial structural mass was 554.7 kg) and a loss of 496 mm3/mm in the workspace volume per unit length. The proposed optimal design procedure could be applied to other serial or parallel mechanism platforms that have geometrically symmetric workspace shapes.

Analytical Derivation of the Pareto-Optimal Set with Application to Structural Design

2020 ◽  
pp. 43-66
Author(s):  
Federico Maria Ballo ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu ◽  
Giorgio Previati
Keyword(s):  
Structural Design ◽  
Pareto Optimal ◽  
Analytical Derivation ◽  
Pareto Optimal Set ◽  
Optimal Set

Multi-Objective Optimization Analysis of Motor Cooling System in Articulated Dump Truck

2011 ◽  
Vol 383-390 ◽  
pp. 4715-4720
Author(s):  
Yan Zhang ◽  
Yan Hua Shen ◽  
Wen Ming Zhang
Keyword(s):  
Field Distribution ◽  
Cooling System ◽  
Dump Truck ◽  
Water Cooling ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Pareto Optimal Set ◽  
Temperature And Pressure ◽  
Water Cooling System ◽  
Optimal Set

In order to ensure the reliable and safe operation of the electric driving motor of the articulated dump truck, water cooling system is installed for each motor. For the best performance of the water cooling system, not only the heat transfer should be enhanced to maintain the motor in relatively low temperature, but also the pressure drop in the water cooling system should be reduced to save energy by reducing the power consumption of the pump. In this paper, the numerical simulation of the cooling progress is completed and the temperature and pressure field distribution are obtained. The multi-objective optimization model is established which involves the cooling system structure, temperature field distribution and pressure field distribution. To improve the computational efficiency, the surrogate model of the simulation about the cooling process is established based on the Response Surface Methodology (RSM). After the multi-objective optimization, the Pareto optimal set is obtained. The proper design point, which could make the average temperature and pressure drop of the cooling system relative desirable, is chosen from the Pareto optimal set.

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