The Research And Application Of Three-Dimensional Components Packing System

The packing problem is to put some objects into a defined space according to the specified need and to make the occupation as small as possible. The object is called packing object and the space is called container. Three-dimensional packing (TDP) is a combinatorial optimization and HP-complete problem and applied widely to the mechanical manufacture and traffic transportation industries. Up to now there are varieties of heuristic algorithms to solve the TDP because of its high complication, we discuss the heuristic algorithm deeply in this paper and apply the simulated annealing (SA) algorithm to the packing system.SA algorithm is to simulate the classical particles in the Thermodynamics in order to seek the extreme value of the design problem. SA is a stochastic optimization technique and a zero-order algorithm requiring no derivative information and has been used extensively to solve continuous, ordered discrete and multi-modal optimization. In this paper we improved the traditional SA algorithm, and the heuristic algorithm is applied to the search and move schedule. The neighborhood is changed from the fixable to the alterable, the operation of moving and rotating is alternate, and the precision of the solution is then guaranteed as well as its convergence speed. We have applied the improved SA to test the three-dimensional packing problem and received a good result.In this paper, a generic objective function consisting of multiple design objectives according to SA is formed. The TDP system is based on the ObjectARX technique, AutoCAD database and the VC++ development language. The characteristics of the configuration class is described based on the object-oriented technology and series of modules and algorithm of detecting interference are designed. In the end, the packing result without constraints of the arbitrary geometry component is realized. The packing system consists of the following modules: the input module, the automatic packing module, the output of the packing result module, and the output of the packing datum module etc.On the basis of the above-mentioned packing system, the characters of the gear box is described in the form of "class", the packing system is then applied to test the example of the gear box (in the gear box verification, we add a constraint module to deal with the specified problem). The gears are simplified to cylinders and the module is formed in AutoCAD. At the end of the paper, we get an optimal value of the packing density and the whole thickness byadding the constraints of gears with the same axes, and constrain the moves of the gears meshed with each other, which are not appeared in the former system and can be selected by the user. At last, a simple prospect for the possible application is given.