Trajectory tracking for a flexible one-link robot using a nonlinear noncollocated output

Abstract

We introduce a method that provides a nonlinear noncollocated output for trajectory tracking of a flexible one-link robot. The link is modeled as a finite-order Lagrangian system obtained from truncated modal analysis. This noncollocated output is derived based on viewing a flexible link robot arm as an underactuated mechanical system and then applying an appropriate change of coordinates that transforms the system into a cascade nonlinear system with a minimum-phase zero dynamics. The output is the angle of rotation augmented with the (generalized) saturation of the weighted amplitudes of the deflection modes of the flexible link.