| Automated methods for generating a general purpose dynamic simulation code are developed for high speed simulation of multibody dynamic systems, on both serial and parallel computers. A preprocessing method based on graph theory is developed to execute topological analysis for general mechanical systems. The topological analysis provides necessary information for equation formulation and parallel processing.;Invariance properties of the velocity state, acceleration state, generalized mass, and generalized force, with respect to the choice of body reference frame, in the velocity state vector formulation of recursive dynamics, are proved. Using these properties, a modified Newton-Euler recursive formulation that defines a body reference frame at the inboard body joint is proposed. It is shown that greater efficiency can be obtained, compared with a traditional recursive formulation that defines a body reference frame at the center of mass of the body.;Libraries for joint, cut constraint, and force elements are established, to simulate broad classes of mechanical systems. A fine grain parallel algorithm that exploits inherent parallelism in the proposed recursive formulation is presented. Computational data flow for a dynamic simulation code to implement the algorithm on a parallel computer is defined.;Finally, a FORTRAN code is written and implemented on an eight processor Alliant FX/8 computer. The accuracy of the code is verified to be as precise as that of the general purpose DADS code. However, the efficiency of the former is much greater than the latter.;An algorithm for initial assembly of a mechanical system that uses relative coordinates as generalized coordinates in recursive formulations is proposed. A formulation for transfomation of Jacobian matrices from the Cartesian space to the joint coordinate space is also derived. |
