Simulation of the Dynamics of Machinery

Abstract

The dynamics of motion of general, two-dimensional machine systems incorporating linkage elements is studied by a procedure which eliminates equation writing. The method is similar to chemical engineering process analysis procedures utilizing an interconnection matrix to describe attachments between components of a system. A digital computer program based on the procedure, termed the Machine Dynamics-Universal System Analyzer (MEDUSA), has been written and tested. This program contains subroutines for simulating the behavior of the following standard components: rigid links, torsional and linear springs, torsional and linear dashpots, force sources, motion generators, and flexible beams. Gears, chain drives, hydraulic transmissions, electric motors, and other components may be added to the simulation without difficulty. To use the program, the engineer follows a standard method to develop a special subroutine calling various component subroutines in proper order. The program computes the accelerations at the centers of mass of the various rigid elements and the interconnection forces simultaneously. Numerical integration alternating with the acceleration computation determines the position and force history of the machine. Experience shows that the engineering effort needed to develop a dynamic simulation of a general machine system using MEDUSA is greatly reduced compared to deriving the equations of motion.