ROTATING STEP BY STEP PIEZOMOTOR FOR NANOPOSITIONING & SPACE APPLICATIONS

Piezomotors are well known in various applications where high precision actuation is required like AFM or handling equipment for semiconductor production. Their specific low speed in direct drive and high torque characteristics combined with high holding torque in off power conditions make them very attractive for any positioning application and especially space mechanisms where low electrical consumption is always sought. A new concept of rotating stepping piezomotor has been developed in the frame of the LISA space project where the mechanism of the telescope orientation was addressed. A full space qualification campaign has been carried out on the piezomotor model. Both thermal behaviour on a [-25, 75]°C range, and a 5.10 5 cycles lifetime have been validated whereas the vibration test was partially successful. The motor characteristics unchanged after the lifetime test display a ±1° rotation angle and a 0.05 rpm speed at 50Hz driving and a positioning resolution measured around 200 nrad. These reliable and high motor performances can answer to demanding positioning requirement including moreover non magnetic specification.