Introduction

A mechanism or a multibody system consists of several bodies or links that move together in a coordinated fashion based on the nature of the connections between them. The individual bodies or links are usually attached through joints such as in robot manipulators, biomechanical systems, mechanisms and machines, or other clever devices such as in aerospace systems. As a system moves, its posture changes, including displacements of the individual bodies while maintaining the connections through the joints.

The classical formulations of kinematics of rigid bodies discussed in Chapter 3 can be adapted to multibody systems. In order to do this, however, we must keep track of all bodies and their interconnections and make sure that their displacements and motions are described in a fashion that allows us to track the posture of the entire mechanism or multibody system. The matrix method presented in this and subsequent chapters provides a systematic method that allows such a development with no ambiguities. When combined with the methods for topological examination of mechanical systems from Chapter 2, the overall approach provides a powerful tool for computer-aided analysis of mechanisms and multibody systems and for development of general-purpose software tools for such applications.