Using Engineering Models to Control Variability: Feasibility Robustness for Worst-Case Tolerances

1993 ◽  
Author(s):  
Gary Emch ◽  
Alan Parkinson
Keyword(s):  
Nonlinear Programming ◽  
Engineering Design ◽  
Test Cases ◽  
Worst Case ◽  
Robust Designs ◽  
Feasibility Robustness ◽  
Programming Techniques ◽  
Engineering Models ◽  
Analytical Tools ◽  
General Method

Abstract Engineering models can and should be used to understand the effects of variability on a design. When variability is ignored, brittle designs can result that fail in service. By contrast, robust designs function properly even when subjected to off-nominal conditions. There is a need for better analytical tools to help engineers develop robust designs. In this paper we present a general method for developing designs that are robust to variability induced by worst-case tolerances. The method adapts nonlinear programming techniques in order to determine how a design should be modified to account for variability. We show how this can be done with second order, or even exact, worst-case tolerance models. Results are given for 13 test cases that span a variety of problems. The method enables a designer to understand and account for the effects of worst-case tolerances, making it possible to build robustness into an engineering design.

Robust Optimal Design for Worst-Case Tolerances

1994 ◽  
Vol 116 (4) ◽  
pp. 1019-1025 ◽  
Author(s):  
G. Emch ◽  
A. Parkinson
Keyword(s):  
Nonlinear Programming ◽  
Optimal Design ◽  
Worst Case ◽  
New Approach ◽  
Robust Designs ◽  
Design Variables ◽  
Robust Optimal Design ◽  
Programming Techniques ◽  
Engineering Models ◽  
Analytical Tools

Engineering models can and should be used to understand the effects of variability on a design. When variability is ignored, brittle designs can result that will not function properly or that will fail in service. By contrast, robust designs function properly even when subjected to off-nominal conditions. There is a need for better analytical tools to help engineers develop robust designs. In this paper we present a new approach for developing designs that are robust to variability induced by worst-case tolerances. An advantage of this approach is that tolerances may be placed on any or all model inputs, whether design variables or parameters. The method adapts nonlinear programming techniques in order to determine how a design should be modified to account for variability. We tested the method under relatively severe conditions on 13 problems, with excellent results. Using this approach, a designer can account for the effects of worst-case tolerances, making it possible to build robustness into an engineering design.

scholarly journals Evolutionary Algorithms for Constrained Parameter Optimization Problems

1996 ◽  
Vol 4 (1) ◽  
pp. 1-32 ◽  
Author(s):  
Zbigniew Michalewicz ◽  
Marc Schoenauer
Keyword(s):  
Nonlinear Programming ◽  
Evolutionary Algorithms ◽  
Evolutionary Computation ◽  
Numerical Optimization ◽  
Optimization Problems ◽  
Optimization Techniques ◽  
Test Cases ◽  
Nonlinear Constraints ◽  
Nonlinear Programming Problem ◽  
General Nonlinear Programming

Evolutionary computation techniques have received a great deal of attention regarding their potential as optimization techniques for complex numerical functions. However, they have not produced a significant breakthrough in the area of nonlinear programming due to the fact that they have not addressed the issue of constraints in a systematic way. Only recently have several methods been proposed for handling nonlinear constraints by evolutionary algorithms for numerical optimization problems; however, these methods have several drawbacks, and the experimental results on many test cases have been disappointing. In this paper we (1) discuss difficulties connected with solving the general nonlinear programming problem; (2) survey several approaches that have emerged in the evolutionary computation community; and (3) provide a set of 11 interesting test cases that may serve as a handy reference for future methods.

Computerized Selection of Optimum Machining Conditions for a Job Requiring Multiple Operations

1978 ◽  
Vol 100 (3) ◽  
pp. 356-362 ◽  
Author(s):  
S. S. Rao ◽  
S. K. Hati
Keyword(s):  
Nonlinear Programming ◽  
Mathematical Programming ◽  
Machine Tools ◽  
Machining Conditions ◽  
Coupling Constraints ◽  
Programming Techniques ◽  
Mathematical Programming Problems ◽  
The Individual ◽  
The Cost ◽  
Selection Of

The problem of determining the optimum machining conditions for a job requiring multiple operations has been investigated. Three objectives, namely, the minimization of the cost of production per piece, the maximization of the production rate and, the maximization of the profit are considered in this work. In addition to the usual constraints that arise from the individual machine tools, some coupling constraints have been included in the formulation. The problems are formulated as standard mathematical programming problems, and nonlinear programming techniques are used to solve the problems.

Nonlinear Mixed Integer-Discrete-Continuous Programming and its Application to Engineering Design Problems

1989 ◽  
Author(s):  
J.-F. Fu ◽  
R. G. Fenton ◽  
W. L. Cleghorn
Keyword(s):  
Nonlinear Programming ◽  
Objective Function ◽  
Engineering Design ◽  
Optimization Algorithm ◽  
Mixed Integer ◽  
Continuous Variables ◽  
Design Problems ◽  
Continuous Programming ◽  
Engineering Design Problems ◽  
Standard Values

Abstract An algorithm for solving nonlinear programming problems containing integer, discrete and continuous variables is presented. Based on a commonly employed optimization algorithm, penalties on integer and/or discrete violations are imposed on the objective function to force the search to converge onto standard values. Examples are included to illustrate the practical use of this algorithm.

A General Method for Computing the Distance Between Two Moving Objects Using Optimization Techniques

1992 ◽  
Author(s):  
Ou Ma ◽  
Meyer Nahon
Keyword(s):  
Quadratic Programming ◽  
Moving Objects ◽  
Optimization Techniques ◽  
Quadratic Constraints ◽  
Space Manipulators ◽  
Programming Techniques ◽  
Distance Problem ◽  
A Minor ◽  
Bounding Surfaces ◽  
General Method

Abstract Presented in this paper is a general method used to find the distance between two moving objects. This distance is defined as the length of the shortest path from one object to the other. The objects are assumed to be composed of arbitrary quadratic surface segments. The distance problem is formulated as a quadratic programming problem with linear and/or quadratic constraints, which is solved by efficient and robust quadratic programming techniques. Attention is focused on implementation in order to achieve computational efficiency for real-time applications. Computing tests show that the computational speed of this method is of linear order in terms of the total number of bounding surfaces of the two objects. It is also shown that, with a minor modification, this method can be used to calculate the interference between objects. A corresponding general software code has been implemented, and will be used for kinematics and dynamics modelling and simulation of space manipulators including situations with transient topologies, contact of environment, and capture/release of payloads.

Influence of Production Profile Engineering Design for Horizontal Well Testing Construction

2014 ◽  
Vol 1073-1076 ◽  
pp. 2282-2285
Author(s):  
Xiao Hua Wang
Keyword(s):  
Engineering Design ◽  
Test Construction ◽  
Actual Condition ◽  
Design For Test ◽  
Test Cases ◽  
Well Testing ◽  
Test Efficiency ◽  
Complex Test ◽  
The Cost

Well testing engineering design must be completed according to the geological and engineering tasks and the actual condition of the well before logging, and then the test preparation completes according to the design. The whole construction process is carried out in accordance with the engineering design, For the complex test cases, it is need to adjust the testing process according to the basis data of engineering design and actual situation, engineering design is very important for the construction of production profile testing of horizontal wells. Engineering design can improve the test efficiency, ensure the accuracy of test data and test safety, reduce the cost of testing. This paper analyzed the role of engineering design in the testing construction and expounds the influence of engineering design for test construction by way of example.

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