The organization is affected by a variety of random factors during the exercise. In order to improve the motion reliability of the mechanism, it is very important to evaluate the motion reliability at the beginning of design. The error model of collaborative robot mechanism is established based on D⁃H method and finite⁃element method. The fourth⁃order moment method is used to establish the mechanism motion reliability model. The reliability model of mechanism motion interval is established based on envelope function method. The model of rigid⁃flexible coupling parameterization with clearance is established by using ADAMS. Motion reliability simulation of collaborative robot was made with ADAMS/insight. And calculate the motion reliability within 9 s. Compared with Monte Carlo simulation（MCS）. The advantages of the fourth⁃moment method and the envelope function method in the analysis of motion reliability are proved.

Three-dimensional clouds for rendering natural scenes are essential. 3D Simplex noise technology is a new kind of noise generation method which is improved by 3D Perlin noise. 3D Simplex noise technology was used to generate 3D noise gray-scale images. Through the noisy image sharpening and color conversion, the 3D Simplex noise images were converted to blue sky and white clouds images, and finally with time function of the GLSL shading language, the fluttering clouds were achieved. The experiment results show that the 3D Simplex noise is low computational complexity to generate realistic images of the cloud and the generated realistic images of the cloud are effective.