Introduction and Basic Concepts

The kinematics and dynamics of multibody systems is an important part of what is referred to as CAD (Computer Aided Design) and MCAE (Mechanical Computer Aided Engineering). Figures 1.1 to 1.6 illustrate some practical examples of computer generated models for the simulation of real multibody systems. The mechanical systems included under the definition of multibodies comprise robots, heavy machinery, spacecraft, automobile suspensions and steering systems, graphic arts and textile machinery, packaging machinery, machine tools, and others. Normally, the mechanisms used in all these applications are subjected to large displacements, hence, their geometric configuration undergoes large variations under normal service conditions. Moreover, in recent years operating speeds have been increased, and consequently, there has been an increase in accelerations and inertial forces. These large forces inevitably lead to the appearance of dynamic problems that one must be able to predict and control.