Fabrication of monolithic piezoelectric drive units for a miniature robot

In this paper, we present the design and assembly of a miniature robot, with a size of a few cm3, which should be able to move freely over distances in the centimetre range performing high precision manipulating operations on micrometre-sized objects with a precision in the nanometre range. The final robot will carry an application specific integrated circuit containing power drivers and a digital control system with a fast serial interface protocol. Two six-legged monolithic piezoelectric drive units generate the motion. Each leg is a three-axial multilayer piezoceramic enabling a five-axial manipulation operation. The fabrication of the drive units is described in detail. The multilayer structures are fabricated with wet building and screen printing. The green material is machined to single components using a high precision CNC micromilling machine. The motion capacity of the legs has been evaluated and major limitations restraining the motion capacity and further miniaturization have been identified. Firstly, the patterning of the internal electrodes should be improved, but also the milling operation has to be considered.