Zero Dynamics in Robotic Systems

Abstract

The notion of zero dynamics of a nonlinear system is used in the investigation of three classes of problems that arise in advanced robotics: control of robots in rigid contact with the environment, free motion control of manipulators with redundant degrees of freedom, and trajectory control of robot arms with flexible links. In each case, the internal dynamics present in the system when a proper output is constrained to be zero is characterized, and a physical interpretation of such dynamics is provided. Simple examples are worked out to show how this analysis supports the design of stabilizing controllers, and that existing results can be reviewed in the spirit of zero dynamics.