Multibody System Dynamics Equations A Computer Automatically Group Set Solving

The dynamics of multibody system plays an important role in many fields such as road and rail vehicle-design,robotics,biomechanics,spacecraft control,and dynamics of machinery. So it has great application value and theoretical significance. In this article all sorts of class libraries for multibody system have been established and the Roberson/Wittenburg method has been used to describe the structure of multibody system. The concept of "path" has been introduced to make the formulation for the kinematics and dynamics of multibody system more concise and least information needed. According to the directions of "paths",the recursive formulas for the kinematic and dynamic of multibody system have been obtained. Based on the principle of virtual work,the one-way recursive method for construction has been presented here. This method has high efficiency in formulation and the analogy in solving the equations of different problems makes it easier to organize the program. The matrices that need determining the inverses are all symmetric and positive definite,and this reduces the calculation and the memory cells of computer. This form of equations has brought convenience to solve the systems without tree structure under the constraint conditions. The Adamas method has been adopted to solve the dynamic equation of multibody system and the data of several forward steps has been repeatedly used,so the speed of computation is high. Based on the aforementioned method,the software for the simulation of multibody system has been organized in this paper,which shows high efficiency and accuracy in the simulation of multibody system.In order to demonstrate the feasibility of the formulation and the program,six calculating examples are supplied finally.