A Method to Identify Reformulations of Mechanical Parametric Constraints to Enhance Design

1990 ◽  
Author(s):  
John D. Watton ◽  
James R. Rinderle
Keyword(s):  
Mechanical Design ◽  
Design Parameters ◽  
Critical Ratio ◽  
Functional Requirements ◽  
Alternative Design ◽  
Functional Behavior ◽  
Highly Nonlinear ◽  
Computer Based ◽  
Fluid Coupling ◽  
Simple Difference

Abstract The complexity of mechanical design is reflected in the complexity of the design equations which relate functional requirements to design parameters. Reformulations of the design equations can significantly reduce this complexity. This is accomplished by a transformation to alternative design parameters, such as a critical ratio, a nondimensional parameter, or a simple difference; e.g. the ratio of surface area to volume for heat transfer loss, the Reynold’s number in fluid mechanics, or the velocity difference across a fluid coupling. We have developed a method by which the alternative parameters are chosen for physical significance and for the ability to create a more direct correspondence to functional behavior as determined by measures of serial and block decomposability of the constraints. Rules have been developed for the creation of physically significant new parameters from the algebraic combination of the original parameters. The rules are based on engineering principles and rely on knowledge about what a parameter physically represents rather than other qualities such as dimensions. A computer based system, called EUDOXUS, has been developed to automate this procedure. The system operates on a set of design constraints to produce sets of transformed constraints in terms of alternative design parameters. The method and its implementation have demonstrated successful results for many highly nonlinear and highly coupled parameterized designs from many mechanical engineering domains.

Identifying reformulations of mechanical parametric design constraints

1991 ◽  
Vol 5 (3) ◽  
pp. 173-188 ◽  
Author(s):  
John D. Watton ◽  
James R. Rinderle
Keyword(s):  
Parametric Design ◽  
Mechanical Design ◽  
Design Parameters ◽  
Critical Ratio ◽  
Functional Requirements ◽  
Dimensional Parameter ◽  
Design Constraints ◽  
Alternative Design ◽  
Functional Behavior ◽  
Highly Nonlinear

The complexity of mechanical design is reflected in the complexity of the design constraints which relate functional requirements to design parameters. Reformulations of the design constraints can significantly reduce this complexity. This is accomplished by a transformation to alternative design parameters, such as a critical ratio, a non-dimensional parameter, or a simple difference; e.g. the ratio of surface area to volume for heat transfer loss, the Reynold's number in fluid mechanics, or the velocity difference across a fluid coupling. We have developed a method by which the alternative parameters are chosen for physical significance and for the ability to create a more direct correspondence to functional behavior as determined by measures of serial and block decomposability of the constraints. Rules have been developed for the creation of physically significant new parameters from the algebraic combination of the original parameters. The rules are based on engineering principles and rely on knowledge about what a parameter physically represents rather than other qualities such as dimensions. A computer based system, called EUDOXUS, has been developed to automate this procedure. The system operates on a set of design constraints to produce sets of transformed constraints in terms of alternative design parameters. The method and its implementation have demonstrated successful results for many highly nonlinear and highly coupled parameterized designs from many mechanical engineering domains.

Enabling Variation of Manufacturing Process Parameters in Early Stages of Product Development

2006 ◽  
Author(s):  
Patrik Boart ◽  
Ola Isaksson
Keyword(s):  
Product Development ◽  
Process Parameters ◽  
Manufacturing Process ◽  
Mechanical Design ◽  
Design Method ◽  
Local Level ◽  
Simulation Models ◽  
Design Parameters ◽  
Functional Requirements ◽  
Early Stages

Currently, mechanical design of aero engine structural components is defined by dimensioning of Design Parameters (DP's) to meet Functional Requirements (FR's). FR's are typically loads, geometrical interfaces and other boundary conditions. Parameters from downstream processes are seldom actually seen as DP's. This paper proposes that downstream process parameters are treated as DP's which calls for engineering methods that can define and evaluate these extended set of DP's. Using the proposed approach manufacturing process alternatives can be used as DP's in early stages of product development. Both the capability to quantitatively assess impact of varying manufacturing DP's, and the availability of these design methods are needed to succeed as an early phase design method. One bottleneck is the preparation time to define and generate these advanced simulation models. This paper presents how these manufacturing process simulations can be made available by automating the weld simulation preparation stages of the engineering work. The approach is based on a modular approach where the methods are defined with knowledge based engineering techniques-operating close to the CAD system. Each method can be reused and used independently of each other and adopted to new geometries. A key advantage is the extended applicability to new products, which comes with a new set of DP's. On a local level the lead time to generate such manufacturing simulation models is reduced with more than 99% allowing manufacturing process alternatives to be used as DP's in early stages of product development.

scholarly journals Kinematic Analysis of a Mechanism With Dual Remote Centre of Motion and its Potential Application

2015 ◽  
Author(s):  
Guochao Bai ◽  
Peng Qi ◽  
Kaspar Althoefer ◽  
Duanling Li ◽  
Xianwen Kong ◽  
...  
Keyword(s):  
Eye Movement ◽  
Surgical Procedures ◽  
Mechanical Design ◽  
The Self ◽  
The Other ◽  
Design Parameters ◽  
Functional Requirements ◽  
Ophthalmic Surgery ◽  
Surgical Tools ◽  
End Effectors

Development of a mechanism with dual remote center of motion (dual-RCM mechanism) intended for teleoperated ophthalmic surgery is reported in this paper. First, characteristics of RCM mechanisms are analyzed. Then, a method to synthesize dual-RCM mechanisms is proposed. Further the mechanical design parameters are optimized to synthesize types of mechanisms meeting functional requirements as well as workspace constraints. The dual-RCM mechanism intended for teleoperated ophthalmic surgery includes two end-effectors: one provides the tool insertion, the other tracks eye movement. The superiority is embodied in the self-synchronized motion of double end-effectors, which allows RCM point of the working instrument to track the penetration point real-time, thereby enhancing microsurgical accuracy. In the proposed implementation, a conceptual helmet mechanical architecture integrating surgical tools with triple-parallelogram linkages is introduced to release the surgeon’s hands by enabling more robotic technologies during the procedures. The vision of the research is to help revolutionize the ophthalmic surgical procedures from bimanual fashion to master-slave teleoperation.

scholarly journals A modular design method based on TRIZ and AD and its application to cutter changing robot

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110343
Author(s):  
Mei Yang ◽  
Yimin Xia ◽  
Lianhui Jia ◽  
Dujuan Wang ◽  
Zhiyong Ji
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Idea Generation ◽  
Design Parameters ◽  
Problem Analysis ◽  
Concept Design ◽  
Functional Requirements ◽  
Shield Tunneling ◽  
Structural Hierarchy ◽  
And Performance

Modular design, Axiomatic design (AD) and Theory of inventive problem solving (TRIZ) have been increasingly popularized in concept design of modern mechanical product. Each method has their own advantages and drawbacks. The benefit of modular design is reducing the product design period, and AD has the capability of problem analysis, while TRIZ’s expertise is innovative idea generation. According to the complementarity of these three approaches, an innovative and systematic methodology is proposed to design big complex mechanical system. Firstly, the module partition is executed based on scenario decomposition. Then, the behavior attributes of modules are listed to find the design contradiction, including motion form, spatial constraints, and performance requirements. TRIZ tools are employed to deal with the contradictions between behavior attributes. The decomposition and mapping of functional requirements and design parameters are carried out to construct the structural hierarchy of each module. Then, modules are integrated considering the connections between each other. Finally, the operation steps in application scenario are designed in temporal and spatial dimensions. Design of cutter changing robot for shield tunneling machine is taken as an example to validate the feasibility and effectiveness of the proposed method.

A Performance Study of Real Coded Genetic Algorithm on Gear Design Optimization

2012 ◽  
Vol 622-623 ◽  
pp. 64-68 ◽  
Author(s):  
S. Padmanabhan ◽  
M. Chandrasekaran ◽  
P. Asokan ◽  
V. Srinivasa Raman
Keyword(s):  
Genetic Algorithm ◽  
Power Efficiency ◽  
Mechanical Design ◽  
Design Solution ◽  
Functional Requirements ◽  
Performance Study ◽  
Gear Design ◽  
Adverse Result ◽  
Real Coded Genetic Algorithm ◽  
Comparative Results

he major problem that deals with practical engineers is the mechanical design and creativeness. Mechanical design can be defined as the choice of materials and geometry, which satisfies, specified functional requirements of that design. A good design has to minimize the most significant adverse result and to maximize the most significant desirable result. An evolutionary algorithm offers efficient ways of creating and comparing a new design solution in order to complete an optimal design. In this paper a type of Genetic Algorithm, Real Coded Genetic Algorithm (RCGA) is used to optimize the design of helical gear pair and a combined objective function with maximizes the Power, Efficiency and minimizes the overall Weight, Centre distance. The performance of the proposed algorithms is validated through LINGO Software and the comparative results are analyzed.

“IRIS” A Computerized High Head Pump Turbine Design System

1977 ◽  
Vol 99 (3) ◽  
pp. 567-577
Author(s):  
S. Chacour ◽  
J. E. Graybill
Keyword(s):  
Mechanical Design ◽  
Design Parameters ◽  
Design System ◽  
Performance Requirements ◽  
Manufacturing Process Planning ◽  
Depth Analysis ◽  
High Head ◽  
Critical Components ◽  
Limited Input Data ◽  
Turbine Design

“IRIS” is a computerized design and structural optimization system capable of generating all the major hydraulic and mechanical design parameters of high head pump/turbines from limited input data. The program will size the unit and select the proper hydraulic passage configuration according to performance requirements and optimize the dimensions of all the major components, generate command tapes used by a numerically controlled flame cutter, estimate cost, and issue manufacturing process planning. It also generates finite element models for the “in depth” analysis of critical components.

scholarly journals HIGH RESOLUTION CAMERA DESIGN PLANNING THEORETICAL FOUNDATIONS FOR DRIVING SYSTEMS

2021 ◽  
Author(s):  
Viacheslav S. Stadnichuk ◽  
Valentin G. Kolobrodov ◽  
Oleksii O. Mosolab ◽  
Denis Yu. Kondratenko ◽  
Dmytro I. Ryabokon
Keyword(s):  
High Resolution ◽  
Optical Glass ◽  
Light Sensitivity ◽  
Design Parameters ◽  
Optical Parameters ◽  
Functional Requirements ◽  
Modulation Transfer ◽  
Road Signs ◽  
Wide Range ◽  
Camera Design

Background. Analysis of statistical data showed that in most cases the cause of the accident is driver error and, as a consequence, violation of traffic rules. In this regard, over the past 10 years, active developments in the field of recognition of road signs and other obstacles in the path of a car have been actively developing. Car manufacturers offer ready-made built-in systems, mounted behind the interior rearview mirror and connected to the car’s on-board computer, which carries out further control of the car in a critical situation. The main disadvantage of these systems of this class is the low range of recognition of road signs, the dependence of optical parameters on temperature and low light sensitivity. Objective. The purpose of the paper is to model an athermal objective for a high-resolution camera, investigate the characteristics of lenses depending on the ambient temperature. Methods. Analysis and modeling of objectives, lenses, optical glass from different materials. Results. A high-resolution camera objective for all types of cars is proposed. An athermal objective was developed for a high-resolution camera. Conclusions. The optimized athermal design of the visible spectrum objective for long-range car cameras is considered. Car cameras typically have a fixed focus, and forward-facing cameras typically require relatively long focal lengths to provide information about distant objects. The optical system for these cameras should provide high resolution, as well as operate in a wide range of ambient temperatures. The camera design parameters are derived from the functional requirements of road sign recognition at a distance of 200 m. The objective design has five lenses with spherical surfaces. The objective has a relative aperture of f/2 and a modulation transfer function (MTF) of more than 0.5 at 111 l/mm over the entire temperature range.

Integration of qualitative and quantitative reasoning in iterative parametric mechanical design

1992 ◽  
Vol 6 (2) ◽  
pp. 95-109 ◽  
Author(s):  
Von-Wun Soo ◽  
Tse-Ching Wang
Keyword(s):  
Parametric Design ◽  
Mechanical Design ◽  
Qualitative Reasoning ◽  
Quantitative Reasoning ◽  
Design Parameters ◽  
Qualitative And Quantitative ◽  
Compression Spring ◽  
Dependency Network ◽  
Previous Design ◽  
Local Variable

A framework IPD (Iterative Parametric Design) is proposed to assist the iterative parametric mechanical design process. To effectively find a set of satisfiable values for the design parameters the key is to find good heuristics to adjust or tune the parametric values resulting from previous design iterations. We propose that heuristics can come from two aspects by both qualitative and quantitative reasoning. Qualitative reasoning, based on confluences, provides global control over the feasible directions of variable adjustments, while quantitative reasoning, based on the dependency network and perturbation analysis, can be used to propose actual quantity of local variable adjustments. We used the design of a helical compression spring as an example to illustrate the performance of IPD system. We show that IPD can often find a solution faster than those without guidance of qualitative and quantitative reasoning.

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