Research And Implementation On Assembly Planning And Virtual Assembly Technology Of Automobile Main Reducer

With the rapid development of industry towards digitalization and automation,virtual assembly technology has become an important research direction in the field of digital design and manufacturing.Virtual assembly technology can realize the transparency and intelligence of product assembly process planning,find out the assembly problems in advance,and check and evaluate the assembly performance,which will greatly shorten the research and development cycle of product assembly process and reduce the assembly cost.So this paper studies the assembly sequence planning,assembly path planning,virtual assembly simulation and other key technologies in the process of virtual assembly,on this foundation,the thesis combines C# programming scripts to develop a set of main reducer virtual assembly system which has multi-scenes such as component observation scene and virtual assembly scene and multi-functions such as automatic assembly and manual assembly based on virtual reality engine Unity3 D and AR device Holo Lens,and it is used in the research and teaching guidance of enterprise products.The specific research content is as follows:Firstly,the multistation assembly sequence planning of the main reducer is studied.The assembly information of the main reducer is expressed in the form of matrix,and the assembly information matrix,assembly interference matrix,assembly connection matrixand and assembly station matrix are established.The evaluation system of multi position assembly sequence considering the factors of product level and position level is established.and the weights of corresponding indexes are determined by analytic hierarchy process.A hybrid algorithm of discrete genetic empire competition for multi station assembly sequence planning is established,and the fusion strategy of the two algorithms is given.The hybrid algorithm is used to iteratively solve the result of station assignment and the optimal assembly sequence.Through case study and comparative analysis,the feasibility and superiority of the proposed algorithm in solving the problem of multiposition assembly sequence planning are proved,which provides the basis for the subsequent assembly path planning and assembly sequence generation in virtual assembly system.Then the assembly path planning in the virtual assembly process of the main reducer is studied.Aiming at the assembly path planning of each station,an assembly path planning method based on the improved empire competition algorithm is proposed.By using convex polyhedron bounding box to surround parts and obstacles,an assembly environment is established,and a path evaluation standard considering two factors of path distance and inflexion number is proposed.In order to improve the efficiency of the algorithm,the generation method of initial state,colony assimilation operator and revolution operator are redefined,colony enhancement operator is added.Through programming,the assembly path planning of the main reducer parts is realized.Through comparison and verification,the algorithm is proved to be better than A* algorithm,which provides the basis for the path planning in the subsequent virtual assembly system.Lastly,based on unity3 d engine and Hololens,combined with C# programming,the virtual assembly system of main reducer in augmented reality environment is designed.Using UG to build 3D model and import it into 3ds Max to complete the preprocessing of the model,including the optimization of the number of faces and map rendering.Import the processed model into unity3 d,the human-machine interaction mechanism of Hololens is used to complete the development of human-machine interaction technology.The OBB level bounding box algorithm and grid collider are used to realize the collision detection in the virtual assembly process of the main reducer.A complete multi station virtual assembly system of the main reducer is developed by combining the assembly sequence planning results,assembly path planning algorithm,user interface design and spatial mapping technology.The system is released to Hololens to complete the visual simulation of the assembly process,and on this basis,the feasibility of assembly sequence planning results,assembly path planning algorithm,human-machine interaction technology and collision detection algorithm is verified.