A FORMALISM FOR THE ANALYSIS AND DESIGN OF MODULAR KINEMATIC STRUCTURES

The exploitation of robotic systems with more complex kinematic struct ures than those of conventional serial chains is widely perceived as o ne of the main avenues of development for robotics. The concept encomp asses systems of different scales and characteristics, such as hybrid manipulators, multifingered hands, cooperative robotic arms walking ma chines, and so on. The underlying kinematic structure of these systems is the same in the sense that they can be regarded as combinations of modules. In this paper we aim to provide a framework for systematical ly identifying, classifying, and combining different modules of such m anipulators. Hence, we introduce a formalism that comprises a set of d efinitions, a symbolic representation of modules, and a set of operati ons based on the kinematic structure, degree of actuation, and mobilit y of the modules. The proposed formalism allows us to efficiently anal yze and synthesize modular manipulators according to their constituent kinematic modules. Moreover the foregoing operations can be easily pe rformed in symbolic form, using commercial software, which makes their implementation generic and more useful. The information that is obtai ned from these operations provides a data base for either designing an inventory of modules or interchanging modules when an inventory of mo dules is available to the system. The application of the proposed form alism is demonstrated through a few examples, one of which pertains to a 7-DOF hybrid manipulator with parallel subchains, whose architectur e is introduced here for the first time.