Orientation Capability, Error Analysis, and Dimensional Optimization of Two Articulated Tool Heads With Parallel Kinematics

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Xin-Jun Liu ◽  
Ilian A. Bonev
Keyword(s):  
Design Space ◽  
Optimization Method ◽  
Thin Wall ◽  
Optimal Solutions ◽  
Parallel Kinematics ◽  
Spherical Joint ◽  
Increasing Demand ◽  
Error Index ◽  
Three Degree Of Freedom ◽  
Dimensional Optimization

Because of the increasing demand in industry for A/B-axis tool heads, particularly in thin wall machining applications for structural aluminium aerospace components, the three-degree-of-freedom articulated tool head with parallel kinematics has become very popular. This paper addresses the dimensional optimization of two types of tool head with 3-P̱VPHS and 3-P̱VRS parallel kinematics (P, R, and S standing for prismatic, revolute, and spherical joint, respectively; the subscripts V and H indicating that the direction of the P joint is vertical or horizontal, and the joint symbol with underline means the joint is active) by considering their orientation capability and positioning accuracy. We first investigate the tilt angle of the spherical joint, the orientation capability, and the error of one point from the mobile platform caused by input errors. Optimization of the 3-P̱VPHS tool head is easy. For the 3-P̱VRS tool head, a design space is developed to illustrate how the orientation capability and error index are related to the link lengths. An optimization process is accordingly presented. Using the optimization method introduced here, it is not difficult to find all the possible optimal solutions.

Design of a Three-Axis Articulated Tool Head With Parallel Kinematics Achieving Desired Motion/Force Transmission Characteristics

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Xin-Jun Liu ◽  
Li-Ping Wang ◽  
Fugui Xie ◽  
Ilian A. Bonev
Keyword(s):  
Parallel Kinematics ◽  
Force Transmission ◽  
Spherical Joint ◽  
Transmission Characteristics ◽  
Design Issue ◽  
Transmission Capability ◽  
High Orientation ◽  
Dimensional Optimization

This paper addresses the design issue of a three-axis tool head with three-PRS parallel kinematics (P, R, and S standing for prismatic, revolute, and spherical joint, respectively) by considering their orientation capability and motion/force transmission. The content presented here is actually an improvement on the dimensional optimization of articulated tool heads with parallel kinematics, with emphasis on the three-PRS design to solve the problem of orientational capability. An index that can evaluate the effectiveness of the motion/force transmission is introduced. The orientation capability with which the mechanism has high motion/force transmission capability is then defined. The procedure searching the link lengths with which the mechanism has a high orientation capability and good effectiveness of motion/force transmission is finally presented.

scholarly journals Designing a Framework for the Estuarine Monitoring System

10.29007/v44x ◽  
2018 ◽  
Author(s):  
Nam-Hoon Kim ◽  
Jin Hwan Hwang
Keyword(s):  
Numerical Model ◽  
Constrained Optimization ◽  
River Discharge ◽  
Design Space ◽  
Optimal Solution ◽  
Optimization Method ◽  
Environmental Data ◽  
Optimal Solutions ◽  
Simulation Data ◽  
Estuarine Monitoring

Where the physical and environmental characteristics of the coast and estuary change dramatically and complicatedly due to the multiple controlling sources as like as the tide, wave, river discharge, in order to collect the environmental data effectively and reliably, the locations of monitoring should be optimally determined with the standardized framework. The present study proposes a protocol to find the best monitoring location in a local bay based on a spatial and temporal optimizing method. With the simulation data from the accurately validated numerical model, the monitoring locations are designed with the constrained optimization method, which finds the optimal solution by constraining the objective function into the design space. The objective and constrained functions are determined from the objective analysis, which is combined with constrained optimization. Finally, those two functions are used to find the optimal solutions of the locations.

scholarly journals An approximate high-dimensional optimization method using hierarchical design space reduction strategy

2021 ◽  
Vol 39 (2) ◽  
pp. 292-301
Author(s):  
Pengcheng Ye ◽  
Congcong Wang ◽  
Guang Pan
Keyword(s):  
Design Space ◽  
Optimization Method ◽  
Surrogate Models ◽  
Black Box ◽  
High Dimensional ◽  
Hierarchical Design ◽  
Reduction Strategy ◽  
Space Reduction ◽  
Ensemble Of Surrogates ◽  
Dimensional Optimization

To overcome the complicated engineering model and huge computational cost, a hierarchical design space reduction strategy based approximate high-dimensional optimization(HSRAHO) method is proposed to deal with the high-dimensional expensive black-box problems. Three classical surrogate models including polynomial response surfaces, radial basis functions and Kriging are selected as the component surrogate models. The ensemble of surrogates is constructed using the optimized weight factors selection method based on the prediction sum of squares and employed to replace the real high-dimensional black-box models. The hierarchical design space reduction strategy is used to identify the design subspaces according to the known information. And, the new promising sample points are generated in the design subspaces. Thus, the prediction accuracy of ensemble of surrogates in these interesting sub-regions can be gradually improved until the optimization convergence. Testing using several benchmark optimization functions and an airfoil design optimization problem, the newly proposed approximate high-dimensional optimization method HSRAHO shows improved capability in high-dimensional optimization efficiency and identifying the global optimum.

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.

Multiobjective optimization of the flaxseed mucilage extraction process using normal-boundary intersection approach

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mariana Souza Rocha ◽  
Luiz Célio Souza Rocha ◽  
Marcia Barreto da Silva Feijó ◽  
Paula Luiza Limongi dos Santos Marotta ◽  
Samanta Cardozo Mourão
Keyword(s):  
Multiobjective Optimization ◽  
Optimization Method ◽  
Extraction Process ◽  
Pareto Optimal ◽  
Pareto Optimal Solutions ◽  
Optimal Solutions ◽  
Fiber Concentration ◽  
Trade Off ◽  
Content Type ◽  
Normal Boundary

PurposeThe mucilage of the Linum usitatissimum L. seed (Linseed) is one of the natural mucilages that presents a great potential to provide a food hydrocolloid with potential applications in both food and pharmaceutical industries. To increase the yield and quality of linseed oil during its production process, it is necessary to previously extract its polysaccharides. Because of this, flax mucilage production can be made viable as a byproduct of oil extraction process, which is already a product of high commercial value consolidated in the market. Thus, the purpose of this work is to optimize the mucilage extraction process of L. usitatissimum L. using the normal-boundary intersection (NBI) multiobjective optimization method.Design/methodology/approachCurrently, the variables of the process of polysaccharide extraction from different sources are optimized using the response surface methodology. However, when the optimal points of the responses are conflicting it is necessary to study the best conditions to achieve a balance between these conflicting objectives (trade-offs) and to explore the available options it is necessary to formulate an optimization problem with multiple objectives. The multiobjective optimization method used in this work was the NBI developed to find uniformly distributed and continuous Pareto optimal solutions for a nonlinear multiobjective problem.FindingsThe optimum extraction point to obtain the maximum fiber concentration in the extracted material was pH 3.81, temperature of 46°C, time of 13.46 h. The maximum extraction yield of flaxseed was pH 6.45, temperature of 65°C, time of 14.41 h. This result confirms the trade-off relationship between the objectives. NBI approach was able to find uniformly distributed Pareto optimal solutions, which allows to analyze the behavior of the trade-off relationship. Thus, the decision-maker can set extraction conditions to achieve desired characteristics in mucilage.Originality/valueThe novelty of this paper is to confirm the existence of a trade-off relationship between the productivity parameter (yield) and the quality parameter (fiber concentration in the extracted material) during the flaxseed mucilage extraction process. The NBI approach was able to find uniformly distributed Pareto optimal solutions, which allows us to analyze the behavior of the trade-off relationship. This allows the decision-making to the extraction conditions according to the desired characteristics of the final product, thus being able to direct the extraction for the best applicability of the mucilage.

Adaptive Geometry Representation of Turbine Vane Frames for Use in Optimization

2021 ◽  
Author(s):  
Sebastian F. Riebl ◽  
Christian Wakelam ◽  
Reinhard Niehuis
Keyword(s):  
Design Space ◽  
Cfd Simulation ◽  
A Priori ◽  
Three Dimensional ◽  
Optimization Method ◽  
Three Dimensions ◽  
Design Parameters ◽  
Adjustment Process ◽  
Turbine Vane ◽  
Integrated Concept

Abstract Turbine Vane Frames (TVF) are a way to realize more compact jet engine designs. Located between the high pressure turbine (HPT) and the low pressure turbine (LPT), they fulfill structural and aerodynamic tasks. When used as an integrated concept with splitters located between the structural load-bearing vanes, the TVF configuration contains more than one type of airfoil with sometimes pronouncedly different properties. This system of multidisciplinary demands and mixed blading poses an interesting opportunity for optimization. Within the scope of the present work, a full geometric parameterization of a TVF with splitters is presented. The parameterization is chosen as to minimize the number of parameters required to automatically and flexibly represent all blade types involved in a TVF row in all three dimensions. Typical blade design parameters are linked to the fourth order Bézier-curve controlled camber line-thickness parameterization. Based on conventional design rules, a procedure is presented, which sets the parameters within their permissible ranges according to the imposed constraints, using a proprietary developed code. The presented workflow relies on subsequent three dimensional geometry generation by transfer of the proposed parameter set to a commercially available CAD package. The interdependencies of parameters are discussed and their respective significance for the adjustment process is detailed. Furthermore, the capability of the chosen parameterization and adjustment process to rebuild an exemplary reference TVF geometry is demonstrated. The results are verified by comparing not only geometrical profile data, but also validated CFD simulation results between the rebuilt and original geometries. Measures taken to ensure the robustness of the method are highlighted and evaluated by exploring extremes in the permissible design space. Finally, the embedding of the proposed method within the framework of an automated, gradient free numerical optimization is discussed. Herein, implications of the proposed method on response surface modeling in combination with the optimization method are highlighted. The method promises to be an option for improvement of optimization efficiency in gradient free optimization of interdependent blade geometries, by a-priori excluding unsuitable blade combinations, yet keeping restrictions to the design space as limited as possible.

Optimal Design of a 2-UPR-RPU Parallel Manipulator

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Feibo Wang ◽  
Qiaohong Chen ◽  
Qinchuan Li
Keyword(s):  
Optimal Design ◽  
Parallel Manipulator ◽  
Design Space ◽  
Parameter Design ◽  
Optimal Parameters ◽  
Force Transmission ◽  
Universal Joint ◽  
Practical Applications ◽  
Optimum Region ◽  
Dimensional Optimization

This paper investigates dimensional optimization of a 2-UPR-RPU parallel manipulator (where U is a universal joint, P a prismatic pair, and R a revolute pair). First, the kinematics and screws of the mechanism are analyzed. Then, three indices developed from motion/force transmission are proposed to evaluate the performance of the 2-UPR-RPU parallel manipulator. Based on the performance atlases obtained, a set of optimal parameters are selected from the optimum region within the parameter design space. Finally, the optimized parameters are determined for practical applications.

scholarly journals Optimum Design of Structural Parameters for Thin-walled Metal Container

2019 ◽  
Vol 288 ◽  
pp. 01007
Author(s):  
Liao Hongbo ◽  
Yang Dan ◽  
Yin Fenglong ◽  
Liang Xiaodong ◽  
Li Erkang ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Optimization Method ◽  
External Pressure ◽  
Test System ◽  
Manufacturing Cost ◽  
Thin Wall ◽  
Pressure Test ◽  
Critical Instability ◽  
Thin Walled ◽  
Better Than

In order to further increase the volume, reduce the weight and manufacturing cost, the key structural parameters of thin-walled metal packing container are optimized. The instability conditions under circumferential external pressure and axial load are analyzed, a mathematical model with the constraint of critical instability strength, the maximum volume and minimum mass as the objective is constructed. Multi-objective optimization method with nonlinear constraints is used to solve the key structural parameters, such as wall thickness, diameter and height, and the optimization result is calculated by fgoalattain() function in the Matlab optimization toolbox. The instability pressure test system is constructed, the instability pressure of the optimized thin-wall metal packing container is tested. The results show that the unstable pressure is higher than 120kPa, which are better than the design index.

Derivative-Free Hybrid Optimization Method for Top Design of Satellite System

2011 ◽  
Vol 308-310 ◽  
pp. 2413-2417
Author(s):  
Ying Guo Chen ◽  
Shuai Lu ◽  
Xiao Lu Liu ◽  
Ying Wu Chen
Keyword(s):  
Optimization Algorithm ◽  
Gaussian Processes ◽  
Design Space ◽  
Optimization Method ◽  
Satellite System ◽  
Pattern Search ◽  
Hybrid Optimization ◽  
Hybrid Optimization Algorithm ◽  
Hybrid Optimization Method ◽  
Derivative Free

This paper combines a derivative-free hybrid optimization algorithm, generalize pattern search (GPS), with Treed Gaussian Processes (TGP) to create a new hybrid optimization algorithm. The goal is to use the method for top design of satellite system, in which the objective or constraint functions usually are computationally expensive black-box functions. TGP model partitions the design space into disjoint regions, and employs independent Gaussian Processes (GP) in each partition to represent the time consumption of true problem responses. Utilizing the TGP, we generate the new “promising” points, which are the combination of model-predicted values and estimated model errors. Then, these points are used to guide GPS search in the design space efficiently. The hybrid optimization method is applied to top design of multi-satellites cooperated observation. The results demonstrate that the proposed method can not only increase the chance of obtaining optimal solution but also cut down the cost of function evaluations.

scholarly journals Power Efficient Rapid Design Space Exploration of Integrated Scheduling and Module Selection in High Level Synthesis

2021 ◽  
Author(s):  
Pallabi Sarkar
Keyword(s):  
Power Consumption ◽  
Design Space Exploration ◽  
Design Space ◽  
Space Exploration ◽  
High Level Synthesis ◽  
Optimal Solutions ◽  
Power Efficient ◽  
Pi Method ◽  
High Level

High level Synthesis (HLS) or Electronic System Level (ESL) synthesis requires scheduling algorithms that have strong capability to reach optimal/near-optimal solutions with significant rapidity and greater accuracy. A novel power efficient scheduling approach using ‘PI’ method has been presented in this thesis that reduces the final power consumption of the solution at the expenditure of minimal latency clock cycles. The proposed scheduling approach is based on ‘Priority indicator (PI)’ metric and ‘Intersect Matrix’ topology methods that have a tendency to escape local optimal solutions and thereby reach global solutions. Application of the proposed approach results in even distribution of allocated hardware functional units thereby yielding power efficient scheduling solutions. The two main novel and significant aspects of the thesis are: a) Introduction of ‘Intersect Matrix’ topology with its associated algorithm which is used to check for precedence violation during scheduling b) Introduction of PI method using Priority indicator metric that assists in choosing the highest priority node during each iteration of the scheduling optimization process. Comparative analysis of the proposed approach has been done with an existing design space exploration method for qualitative assessment using proposed ‘Quality Cost Factor (Q- metric)’. This Q-metric is a combination of latency and power consumption values for the solution found, which dictates the quality of the final solutions found in terms of cost for both the proposed and existing approaches. An average improvement of approximately 12 % in quality of final solution and average reduction of 59 % in runtime has been achieved by the proposed approach compared to a current scheduling approach for the DSP benchmarks.

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