Research On Assembly Simulation Technology Based On Virtual Hand Operation In VR Environment

The current virtual assembly system design is often centered on functions and technologies.The interactive experience of human reality(VR,Virtual Reality)is not taken into account,and the virtual assembly technology has not been applied in the industry.With the continuous development of virtual reality technology,in the field of virtual assembly,the research goals of domestic and foreign scholars have gradually changed from the realization of basic assembly functions to the improvement of user assembly operation experience.It is shortcoming to the traditional virtual assembly system,such as insufficient interaction means,complicated assembly operation and weak immersion.This paper studies the assembly simulation technology based on virtual hand operation in VR environment,aiming at reducing the cognitive load and operation load of people in the interaction process,and realizes the transformation of virtual assembly system from function-oriented to user-oriented interaction experience.Provide new methods and means for the assembly test of mechanical products,assembly process planning and analysis,assembly operation training and guidance.The main work completed by the thesis and the research results obtained are as follows:(1)Designed an assembly simulation system framework based on virtual hand operation in VR environment.Firstly,the functional requirements of the assembly simulation system are analyzed.On this basis,the overall design scheme of the assembly simulation system is proposed.The operation flow of the system is given and the software and hardware architecture of the system is introduced.Point out the direction for the follow-up study of the paper.(2)Research on virtual hand operation techniques for virtual assembly.According to the characteristics of virtual hand and mechanical parts,the collision detection model of virtual hand and part is established,so that the virtual hand and the part can fully contact;on this basis,the contact point of the virtual hand and the part is calculated,and the penetration of the virtual hand and the part is solved.The problem is analyzed;the existing grasping method is analyzed,and a virtual hand grabbing method for adapting the shape of the part is given.By comparing the physical phenomenon of the actual grabbing of the object,the concept of grasping the pair is defined as the judgment condition of stable grabbing;The hand grabs the contact point set of the part and solves the pose matrix of the virtual hand-transformed part to ensure the precision of the virtual hand-operated part.Finally,the effectiveness of the proposed method is verified by the operation examples of different parts.(3)The assembly process simulation method integrating physical behavior and geometric constraints is studied.Analyze the behavior characteristics of the parts of the assembly task,divide the assembly process of the parts into the free operation stage and the assembly operation stage,adopt different simulation techniques for different stages,and improve the deficiencies of the previous single assembly process;for the part physics in the free operation stage The behavior adopts the physics-based assembly process simulation method,and the assembly process simulation method based on geometric constraints is adopted for the assembly behavior of the assembly operation phase.Finally,the feasibility of the integration method is verified by an example.Based on the above research results,an assembly simulation system based on virtual hand operation is developed based on the Unity3D virtual reality engine.By establishing a virtual assembly environment consistent with the real assembly environment,LeapMotion and HTC VIVE are used as interactive devices to perform interactive assembly verification using typical mechanical products.