<title>Smart robotic manipulator systems consisting of a thin-walled beam and a spinning tip rotor: vibration and stability control</title>

Abstract

ABSTRACT Vibration and stability feedback control of a robotic manipulator modeled as a cantilevered thin-walled beam carryinga spinning rotor at its tip are investigated. The control is achieved via incorporation of adaptive capabilities that areprovided by a system ofpiezoactuators bonded or embedded into the master structure. Based on converse piezoelectriceffect, the piezoactuators produce a localized strain field in response to an applied voltage, and as a result, an adaptivechange of vibrational and stability response characteristics is obtained. A feedback control law relating the piezoelec-trically induced bending moments at the beam tip with the kinematical response quantities appropriately selected isused, and the beneficial effects of this control methodology upon the closed-loop eigenvibration characteristics andstability boundaries are highlighted. The cantilevered structure modelled as a thin-walled beam, and built-up from acomposite material, encompasses non-classical features, such as anisotropy, transverse shear and secondary warping,and in this context a special ply-angle configuration inducing a structural coupling between flapping-lagging trans-verse shear is implemented. It is also shown that the directionality property of the material of the host structure usedin conjunction with piezoelectric strain actuation capability, yields a dramatic enhancement of both the vibrational andstability behavior of the considered structural system.Keyword: Smart robotic manipulator; Thin-walled beams; Spinning tip rotor; Anisotropy; Piezoactuator; Gyro-scopic systems; Divergence and flutter instabilities.