Adaptive layered Cartesian cut cell method is presented to solve the difficulty of the unstructured hexahedral anisotropic Cartesian grids generation from the complex CAD model. Vertex merging algorithm based on relaxed AVL tree is investigated to construct topological structure for stereo lithography (STL) files,and a topology-based self-adaptive layered slicing algorithm with special features control strategy is brought forward. With the help of convex hull,a new points-in-polygon method is employed to improve the Cartesian cut cell method. By integrating the self-adaptive layered slicing algorithm and the improved Cartesian cut cell method,the adaptive layered Cartesian cut cell method gains the volume data of the complex CAD model in STL file and generates the unstructured hexahedral anisotropic Cartesian grids.
A unilateral non-penetration constraint dynamical simulation model with friction is constructed based on compliant model for mechanical system VP (virtual prototyping) simulation. This model combines computer graphics with multi-body system dynamics. It avoids handling multiplicity of solution, such as cases of no solution, multi-solution brought about by friction during traditional construction of non-penetration constraint based on rigid model. At the same time, the realism of VE (virtual environment) is improved in process of simulation. Furthermore, the valid condition of rolling and sliding unilateral contact is constituted based on singular perturbation and linear complementary theory. Finally, the compliant method is verified by an interaction between a multi-legged robot and VE.
