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

Abstract

Vibration and stability feedback control of a robotic manipulator modeled as a cantilevered thin-walled beam carrying a spinning rotor at its tip are investigated. The control is achieved via incorporation of adaptive capabilities that are provided by a system of piezoactuators bonded or embedded into the master structure. Based on converse piezoelectric effect, the piezoactuators produce a localized strain field in response to an applied voltage, and as a result, an adaptive change of vibrational and stability response characteristics is obtained. A feedback control law relating the piezoelectrically induced bending moments at the beam tip with the kinematical response quantities appropriately selected is used, and the beneficial effects of this control methodology upon the closed-loop eigenvibration characteristics and stability boundaries are highlighted. The cantilevered structure modeled as a thin-walled beam, and built-up from a composite material, encompasses on-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 transverse shear is implemented. It is also shown that the directionality property of the material of the host structure used in conjunction with piezoelectric strain actuation capability, yields a dramatic enhancement of both the vibrational and stability behavior of the considered structural system.