Piezoelectric Stewart platform for general purpose active damping interface and precision control

Abstract

This paper discloses a stiff active interface wherein a six degree of freedom Stewart platform, a standard hexapod with a cubic architecture, is used to actively increase the structural damping of flexible systems attached to it. It can also be used to rigidly connect arbitrary substructures while damping them. Each leg of the active interface consists of a linear piezo electric actuator, a collocated force sensor and flexible tips for the connections with the two end plates. By providing the legs with strain or elongation sensors, this active interface can also be used as an interface with infinite stiffness at low frequency (i.e. for machine tools), a 6 d.o.f. positioning and steering device for space applications as well as a microvibration isolator. The translation and rotation strokes of the interface are 90, 103 and 95 µm in the x, y and z directions respectively and 1300, 1150 and 700 µrad around the x, y and z directions respectively