Researches On Rigid Bodies Assembly Problem In Synchronous Modeling Technology Based On Wu Elimination Method

3D geometric constraint solving technology is one of the core technology of CAD systems based on synchronous modeling technology, which is widely used in robotics, linkage design, molecular structure design, computer vision, and so on. As a typical model of CAD application, the essence of assembly model is the assembly constraint solving. It is significant to research the assembly of two rigid bodies in synchronous modeling technology both in theory and application.Assembly constraint solving problem in three dimension is studied, where assembly parts consist of rigid body with six degrees of freedom and rotor with five degrees of freedom. The combinations of assembly constraints are classified. Then for the constraint types 3D3A,4D2A and 3D2A, the correspoding coordinate transformation matrixes are obtained with symbolic computation method based on wu elimination method, to get the position of assembly partssatisfied the given constraint conditions and the parameter ranges to obtain specified number of real solutions. Finally examples are used to verify the effectiveness of the method.The symbolic computation method based on wu elimination method is used to study assembly constraints solving problem in 3D. The correponding symbolic solutions and classifications of real solutions are given, which provide strong support for problems of how to select appropriate parameters in the process of assembly design. The research results has important theoretical and applicational value for 3D geometric constraint solving techiques and its applicational fields.