Research On Virtual Assembly Process Planning And Related Techniques Based On Intelligence Computing

The virtual assembly has brought the newly design for the industry of manufacturing, and the technology relief the traditional process from design, production and constantly trial process. Assembly process planning is the most crucial part of the virtual assembly. This paper focuses on the deeply study in the area of virtual assembly process planning based on intelligence computation. The main thesis is as follows:For virtual assembly process complexity, proposed the product-hierarchical information model for the assembly planning. The informations of part model are stored in sequence in the parts attribute layer, the surface layer of film shows, the assembly relation layer, the information process layer, these layers implementation the linkages between information-model level by the data constraints and mapping by part index number. The constraint among parts assembling process is described as the assembly semantics, build interference matrix and the linear degrees of freedom matrix to describe the relations between parts. Using information describing the process in the assembly model for acquire the assembly sequence, path and other dynamic descriptions. Evaluate the relationship between the part model with the process information. Hierarchy information model convenience the assembly system according to different tasks to operate at different information model.To solving the combinatorial explosion phenomenon during the solving process of virtual assembly sequence, this paper proposed a method for obtain the assembly sequence using ant colony algorithm based on the establishment of the demolition interference matrix. Only the ant which has found the optimal disassembly sequence in once iteration cycle could release global pheromone in the corresponding path; the number of ants is equal to the number of initial feasible demolition operations. Constraints between parts reduce the demolition times of the initial algorithm operation, limit the selection of the solution space, improve the efficiency of the algorithm.Combining the characteristics of genetic algorithm and ant colony algorithm for assembly sequence, this paper proposed Hybrid Genetic-Ant Colony Algorithm for optimal assembly sequence. The main idea of the algorithm followed:When the ants after a tour, the feasible seqence which is constructed by ants as a part of initial population of genetic algorithm. Then the genetic algorithm global optimized the feasible assembly sequence constructed by ants, according to the quality of solution release corresponding concentration of pheromone in the corresponding ant crawling path. Cycle crossover called the genetic algorithm and ant colony algorithm to increase solving ability of the ant colony algorithm.This paper proposed a method with genetic algorithm and grid for assembly path planning. The method used grid to describe the initial location and the space environment map of assembly object. Adopt the serial number of the grid path as the population of individual coding, but not the traditional binary code. The fitness function convertion is used for find the optimal assembly path, it ensured the path of virtual assembly process is the optimal one. It's improve the search efficiency, and avoid the local minimum problems of the traditional search algorithms.Built a system of thruster module virtual assembly, proposed construction of the system and architecture adopt memory scheduling strategy, multi-threaded motion control to improve the performance of assembly systems. Adopt the collision interference removed based on the relative position, then complete the installation of assembly by restrict the assembly location changes. Proposed a scene scheduling strategy based on RBF neural network, use the current the state point of virtual avator as the input sample, then forecast the current status of the follow-up point of view through RBF neural network. Once the current status of the follow-up point of view is obtained, scheduling scenarios can be carried out through the combination of visual cone for shooting. The avator deeply observe the assembly process plan in the wandering process, this method made the assembly process could be truly look back upon.