Piezoelectric actuators for micro positioning stages in automated machines: Experimental characterization of open loop implementations

This paper presents an experimental characterization of an industrial, entry level piezoelectric device with open loop control, whose working principle is based on friction. As a consequence, the length of the single step is dependent on the applied load. Test results confirm the strong dependence existing between the stroke length and the resistance force and are used to design some possible practical applications, both for automated machine common subsystems (positioning stages, gripping tools) and for an innovative differential mechanism which combines their output movement with the one generated with a traditional, larger DC motor, to obtain high torques and accurate positioning at competitive cost.