On the stability of the robot compliant motion control (input output approach)

The work presented here is a practical, nonlinear controller design methodology for robot manipulators. This methodology guarantees: 1) the robot end-point follows an input command vector "closely" when the robot is not constrained by the environment, and 2) the contact force is a function of the same input command vector (used in the unconstrained environment) when the robot is constrained by the environment. The controller is capable of "handling" both constrained and unconstrained maneuverings, and is robust to bounded uncertainties in the robot dgnamics. The controller does not need any hardware or software switch for the transition between unconstrained and constrained maneuvering. Stability of the environment and the manipulator as a whole has been investigated, and a bound for stable manipulation has been derived.