The motive of this research is to develop a good stacking method with an
automatic material handling system and the procedures that can increase productivity,
reduce production costs, and prevent labor injury. A diversity of products leads to a
number of different kinds of stacking problems. Much research has been done focusing
on two-dimensional arrangement for rectangles, circles or irregular shapes, and threedimensional
regular-shaped objects such as rectangular boxes. To solve stacking
problems, many algorithms such as the genetic algorithm, simulated annealing and other
heuristic algorithms have been proposed.
The three-dimensional stacking problem has a practical application in the
transportation, manufacturing, and construction industries. There has been relatively little
emphasis on three-dimensional irregular objects; however, stacking three-dimensional
irregular objects has become more common in industry. In this thesis research, three
heuristic algorithms are proposed to stack irregular stone pieces nested in a container
with multiple layers. Primary functions of the heuristic algorithms include three major
parts. First, it approximates irregular shapes to a cluster of straight lines. Secondly, it
arranges the approximated angles one-by-one with the proposed step-by-step rule. Finally,
it considers the weight of the stone pieces from the pixel calculation for reasons of stability. The first and second algorithms are based on the area and angle of the stone
piece and the third one is based on the approximated weight of the stone.
An automatic real-time stacking system including pneumatic devices, sensors,
relays, a conveyor, a programmable logic controller, a robotic arm, and a vision system
was developed for this study. The algorithms developed were tested by this automatic
stacking system for better utilization. Three performance measures were presented in the
experimental result.
Comparisons between the results from three proposed algorithms and that from
the bottom-back-left algorithm are made. Experimental data demonstrate that the
utilizations and the stabilities of the three proposed algorithms are statistically better than
that of the bottom-back-left algorithm. However, the cycle times of the three proposed
algorithms have no statistical difference from that of the bottom-back-left algorithm. In
addition, a statistical test between each proposed algorithm is also conducted. Both the
utilizations and stabilities have statistical differences between each proposed algorithm
while the cycle times do not. The results of this study show that the algorithm
developed works effectively for solving the stone-pieces stacking problem.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/ETD-TAMU-2010-08-8338 |
| Date | 2010 August 1900 |
| Creators | Ko, Ming-Cheng |
| Contributors | Hsieh, Sheng-Jen |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | thesis, text |
| Format | application/pdf |
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