Design Optimization of Rigid Body Mechanism Topology

2007 ◽  
Author(s):  
Kai Sedlaczek ◽  
Peter Eberhard
Keyword(s):  
Rigid Body ◽  
Development Process ◽  
Combinatorial Problem ◽  
Optimization Techniques ◽  
Dimensional Synthesis ◽  
Ground Structure ◽  
Overall Design ◽  
Modern Computer ◽  
Gradient Based ◽  
Computer Based

Despite modern computer based design tools, the development process of new mechanisms is still based on the engineer’s experience, intuition and ingenuity. The goal of this work is to find a combination of linkage topology and joint types that represent the most suitable mechanism layout for a particular task. Optimization techniques are hardly used for this design problem except for the task of dimensional synthesis of a given mechanism type. This study presents and compares two different approaches to topology or type optimization of planar rigid body mechanisms that can be used to improve the overall design process. The first approach is based on a truss-like ground structure that represents an over-determined system of rigid bars where the most appropriate topology can be extracted from this ground structure by means of gradient based optimization algorithms. In the second approach, we use a genetic algorithm for the intrinsically combinatorial problem of topology synthesis. We explain both approaches and show their capabilities, their advantages and drawbacks.

Topology Optimization of Large Motion Rigid Body Mechanisms With Nonlinear Kinematics

2009 ◽  
Vol 4 (2) ◽  
Author(s):  
Kai Sedlaczek ◽  
Peter Eberhard
Keyword(s):  
Topology Optimization ◽  
Rigid Body ◽  
Design Process ◽  
Combinatorial Problem ◽  
Optimization Techniques ◽  
Dimensional Synthesis ◽  
Ground Structure ◽  
Geometrical Properties ◽  
Manual Task ◽  
Large Motion

The modern design process of mechanical structures is increasingly influenced by highly sophisticated methods of topology optimization that can automatically synthesize optimal design variants. However, the typically finite-element-based methods are limited to design tasks with comparably small deflections and simple kinematics. They are not directly applicable to the difficult development process of large motion mechanisms, which remains mainly a manual task based on the engineer’s experience, intuition, and ingenuity. There, optimization techniques are only, if at all, used in the process of dimensional synthesis, where the geometrical properties and the orientation of individual links of a fixed mechanism topology are determined. In this work, two different approaches to optimization-based topology synthesis of large motion rigid body mechanisms are presented and investigated. The goal is to automatically synthesize a combination of linkage topology and joint types that represent the most suitable mechanism layout for a particular task. The first approach is based on a trusslike ground structure that represents an overdetermined system of rigid bars from which the most appropriate topology can be extracted from this ground structure by means of gradient-based optimization algorithms. In the second approach, a genetic algorithm is used to solve the intrinsically combinatorial problem of topology synthesis. Along with several examples, both approaches are explained, their functionality is shown, and their advantages, limitations, and their capability to improve the overall design process is discussed.

scholarly journals The GENUS aircraft conceptual design environment

2018 ◽  
Vol 233 (8) ◽  
pp. 2932-2947 ◽  
Author(s):  
H Smith ◽  
D Sziroczák ◽  
GE Abbe ◽  
P Okonkwo
Keyword(s):  
Practical Reasoning ◽  
Design Method ◽  
Aircraft Design ◽  
Theoretical Background ◽  
Optimization Techniques ◽  
Design Environment ◽  
Modern Computer ◽  
Computer Based ◽  
Design Software ◽  
Aircraft Conceptual Design

The design of aircraft has evolved over time from the classical design approach to the more modern computer-based design method utilizing multivariate design optimization. In recent years, aircraft concepts and configurations have become more diverse and complex thus pushing many synthesis packages beyond their capability. Furthermore, many examples of aircraft design software focus on the analysis of one particular concept thus requiring separate packages for each concept. This can lead to complications in comparing concepts and configurations as differences in performance may originate from different prediction toolsets being used. This paper presents the GENUS Aircraft Design Framework developed by Cranfield University’s Aircraft Design Group to address these issues. The paper reviews available aircraft design methodologies and describes the challenges faced in their development and application. Following this, the GENUS aircraft design environment is introduced, along with the theoretical background and practical reasoning behind the program architecture. Particular attention is given to the programming, choice of methodology, and optimization techniques involved. Subsequently, some applications of the developed methodology, implemented in the framework are presented to illustrate the diversity of the approach. Three special classes of aircraft design concept are presented briefly.

Sequential vs. Concurrent Formulations for the Synthesis of Engineering Designs

1991 ◽  
Author(s):  
H. M. Karandikar ◽  
J. Rao ◽  
F. Mistree
Keyword(s):  
Life Cycle ◽  
Concurrent Engineering ◽  
Development Process ◽  
Optimization Theory ◽  
Optimization Techniques ◽  
Product Development Process ◽  
Dimensional Synthesis ◽  
Engineering Designs

Abstract Modeling and gaining an understanding of the interaction between information from design and from manufacturing is an important step in developing techniques and methods for concurrent engineering. In this paper, the role of optimization techniques in the product development process in a concurrent engineering framework is examined. Through arguments based in optimization theory, it is demonstrated that a concurrent approach to designing for manufacture problems is superior to a sequential one. By extension, this applies to designing for other life-cycle processes. Results which illustrate the point are presented from a comprehensive, non-textbook case study in design using composite materials and dealing with the integration of analysis, dimensional synthesis, and manufacturing. The case study is tackled by using Decision Support Problems. The focus in the paper is on understanding the ramifications of considering life-cycle processes concurrently.

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.

Design of Locomotive Coupling Transmission System Based on WLAN

2012 ◽  
Vol 590 ◽  
pp. 361-366
Author(s):  
Fu Qiu ◽  
De Qiang He ◽  
Xiao Yang Yao ◽  
Jian Miao
Keyword(s):  
Operating System ◽  
Data Transmission ◽  
System Reliability ◽  
Development Process ◽  
Transmission System ◽  
New Method ◽  
Embedded Operating System ◽  
Overall Design ◽  
Heavy Haul ◽  
Hardware Structure

The locomotive coupling came from the development of heavy-haul transportation in railway. Considering the insufficiencies of cable and radio in locomotive coupling at present, a new method of locomotive coupling is presented in this paper. The overall design of system scheme is provided based on WLAN. The system feasibility is analyzed and verified by using OPNET Modeler. The hardware structure of coupling transmission device and development process of embedded operating system are described briefly. Finally, taking measures guarantees the system reliability of data transmission.

Approximate Motion Synthesis of Open and Closed Chains via Parametric Constraint Manifold Fitting: Preliminary Results

2003 ◽  
Author(s):  
Pierre M. Larochelle
Keyword(s):  
Optimization Techniques ◽  
Robotic Systems ◽  
Dimensional Synthesis ◽  
Motion Synthesis ◽  
Open Chain ◽  
Constraint Manifold ◽  
Synthesis Technique ◽  
Numerical Design ◽  
Design Case ◽  
Parametric Constraint

In this paper we present a novel dyad dimensional synthesis technique for approximate motion synthesis. The methodology utilizes an analytic representation of the dyad’s constraint manifold that is parameterized by its dimensional synthesis variables. Nonlinear optimization techniques are then employed to minimize the distance from the dyad’s constraint manifold to a finite number of desired locations of the workpiece. The result is an approximate motion dimensional synthesis technique that is applicable to planar, spherical, and spatial dyads. Here, we specifically address the planar RR, spherical RR and spatial CC dyads since these are often found in the kinematic structure of robotic systems and mechanisms. These dyads may be combined serially to form a complex open chain (e.g. a robot) or when connected back to the fixed link they may be joined so as to form one or more closed chains (e.g. a linkage, a parallel mechanism, or a platform). Finally, we present some initial numerical design case studies that demonstrate the utility of the synthesis technique.

A Parameterization of the Central Axis Congruence Associated with Four Positions of a Rigid Body in Space

1993 ◽  
Vol 115 (3) ◽  
pp. 547-551 ◽  
Author(s):  
J. M. McCarthy
Keyword(s):  
Rigid Body ◽  
The Body ◽  
Central Axis ◽  
Spatial Mechanisms ◽  
Center Point ◽  
Point Curve ◽  
Screw Surface ◽  
Computer Based

Given four positions of a rigid body in space, there is a congruence of lines that can be used as the central axes of cylindric cranks to guide the body through the four positions. This “central axis congruence” is a generalization of the center point curve of planar kinematics. It is known that this congruence is identical to the screw congruence which arises in the study of complementary screw quadrilateral. It is less well-known that the screw congruence is the “screw surface” of the 4C linkage formed by the complementary screw quadrilateral, and it is this relationship that we use to obtain a parameterization for the screw congruence and in turn, the central axis congruence. This parameterization should facilitate the use of this congruence in computer based design of spatial mechanisms.

scholarly journals Performance of Gradient-Based Solutions versus Genetic Algorithms in the Correlation of Thermal Mathematical Models of Spacecrafts

2017 ◽  
Vol 2017 ◽  
pp. 1-12
Author(s):  
Eva Anglada ◽  
Laura Martinez-Jimenez ◽  
Iñaki Garmendia
Keyword(s):  
Genetic Algorithms ◽  
Mathematical Models ◽  
International Space Station ◽  
Space Station ◽  
Real Space ◽  
Optimization Techniques ◽  
International Space ◽  
Thermal Test ◽  
Gradient Based ◽  
Pros And Cons

The correlation of the thermal mathematical models (TMMs) of spacecrafts with the results of the thermal test is a demanding task in terms of time and effort. Theoretically, it can be automatized by means of optimization techniques, although this is a challenging task. Previous studies have shown the ability of genetic algorithms to perform this task in several cases, although some limitations have been detected. In addition, gradient-based methods, although also presenting some limitations, have provided good solutions in other technical fields. For this reason, the performance of genetic algorithms and gradient-based methods in the correlation of TMMs is discussed in this paper to compare the pros and cons of them. The case of study used in the comparison is a real space instrument flown aboard the International Space Station.

Designing Planar Mechanisms Using a Bi-Invariant Metric in the Image Space of SO (3)

1994 ◽  
Author(s):  
Pierre Larochelle ◽  
J. Michael McCarthy
Keyword(s):  
Rigid Body ◽  
Numerical Results ◽  
Image Space ◽  
Dimensional Synthesis ◽  
Invariant Metric ◽  
Planar Mechanisms ◽  
Position And Orientation ◽  
Position Synthesis

Abstract In this paper we present a technique for using a bi-invariant metric in the image space of spherical displacements for designing planar mechanisms for n (> 5) position rigid body guidance. The goal is to perform the dimensional synthesis of the mechanism such that the distance between the position and orientation of the guided body to each of the n goal positions is minimized. Rather than measure these distances in the plane, we introduce an approximating sphere and identify rotations which are equivalent to the planar displacements to a specified tolerance. We then measure distances between the rigid body and the goal positions using a bi-invariant metric on the image space of SO(3). The optimal linkage is obtained by minimizing this distance over all of the n goal positions. The paper proceeds as follows. First, we approximate planar rigid body displacements with spherical displacements and show that the error induced by such an approximation is of order 1/R2, where R is the radius of the approximating sphere. Second, we use a bi-invariant metric in the image space of spherical displacements to synthesize an optimal spherical 4R mechanism. Finally, we identify the planar 4R mechanism associated with the optimal spherical solution. The result is a planar 4R mechanism that has been optimized for n position rigid body guidance using an approximate bi-invariant metric with an error dependent only upon the radius of the approximating sphere. Numerical results for ten position synthesis of a planar 4R mechanism are presented.

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