Process Planning Optimization In Reconfigurable Manufacturing Systems
Trends and perspectives in dynamic environments point towards a need for optimal operating levels in reconfigurable manufacturing activities. Central to the goal of meeting this need is the issue of appropriate techniques for manufacturing process planning optimization in reconfigurable manufactu...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English English |
| Published: |
2008
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/5420/1/FK_2008_43.pdf |
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| Summary: | Trends and perspectives in dynamic environments point towards a need for optimal
operating levels in reconfigurable manufacturing activities. Central to the goal of
meeting this need is the issue of appropriate techniques for manufacturing process
planning optimization in reconfigurable manufacturing, i.e. (i) what decision making
models and (ii) what computational techniques, provide an optimal manufacturing
process planning solution in a multidimensional decision variables space? Conventional
optimization techniques are not robust, hence; they are not suitable for handling
multidimensional search spaces. On the other hand, process planning optimization for
reconfigurable manufacturing is not amenable to classical modeling approaches due to
the presence of complex system dynamics. Therefore, this study explores how to model
reconfigurable manufacturing activities in an optimization perspective and how to
develop and select appropriate non-conventional optimization techniques for
reconfigurable process planning.In this study, a new approach to modeling Manufacturing Process Planning
Optimization (MPPO) was developed by extending the concept of manufacturing
optimization through a decoupled optimization method. The uniqueness of this
approach lies in embedding an integrated scheduling function into a partially integrated
process planning function in order to exploit the strategic potentials of flexibility and
reconfigurability in manufacturing systems. Alternative MPPO models were constructed
and variances associated with their utilization analyzed. Five (5) Alternative Algorithm
Design Techniques (AADTs) were developed and investigated for suitability in
providing process planning solutions suitable for reconfigurable manufacturing. The
five (5) AADTs include; a variant of the simulated annealing algorithm that implements
heuristic knowledge at critical decision points, two (2) cooperative search schemes
based on a “loose hybridization” of the Boltzmann Machine algorithm with (i)
simulated annealing, and (ii) genetic algorithm search techniques, and two (2) modified
genetic algorithms.
The comparative performances of the developed AADTs when tasked to solve an
instance of a MPPO problem were analyzed and evaluated. In particular, the relative
performances of the novel variant of simulated annealing in comparison to: (a) (i) a
simulated annealing search, and (ii) a genetic search in the Boltzmann Machine
Architecture, and (b) (i) a modified genetic algorithm and (ii) a genetic algorithm with a
customized threshold operator that implements an innovative extension of the diversity
control mechanism to gene and genome levels; were pursued in this thesis.Results show that all five (5) AADTs are capable of stable and asymptotic convergence
to near optimal solutions in real time. Analysis indicates that the performances of the
implemented variant of simulated annealing are comparable to those of other
optimization techniques developed in this thesis. However, a computational study
shows that; in comparison to the simulated annealing technique, significant
improvements in optimization control performance and quality of computed solutions
can be realized through implementing intelligent techniques. As evidenced by the
relative performances of the implemented cooperative schemes, a genetic search is
better than a simulated annealing search in the Boltzmann Machine Architecture. In
addition, little performance gain can be realized through parallelism in the Boltzmann
Machine Architecture. On the other hand, the superior performance of the genetic
algorithm that implements an extended diversity control mechanism demonstrates that
more competent genetic algorithms can be designed through customized operators.
Therefore, this study has revealed that extending manufacturing optimization concepts
through a decoupled optimization method is an effective modeling approach that is
capable of handling complex decision scenarios in reconfigurable manufacturing
activities. The approach provides a powerful decision framework for process planning
optimization activities of a multidimensional nature. Such an approach can be
implemented more efficiently through intelligent techniques. Hence; intelligent
techniques can be utilized in manufacturing process planning optimization strategies
that aim to improve operating levels in reconfigurable manufacturing with the resultant
benefits of improved performance levels. |
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