Optimized friction drive controller for a multi-DOF ultrasonic nanopositioner

This paper presents a new generation of compliant multidegree of freedom (DOF) piezoelectric nanopositioner for positioning, transport, alignment of microobjects under the field of view of a microscope. It is based on the cooperation of arrayed direct-drive standing wave ultrasonic actuators (microSWUMs). An optimized friction drive multidimensional controller is proposed based on: (i) an electromagnetic field-based preload controller ensuring optimal preload , (ii) an open-loop PWM controller for self-locking and driving force control and (iii) a resonant frequency compensation.