Physical and Control System Design Challenges in Large Range Nanopositioning

There is an increasing need for compact desktop-size nanopositioning systems that can provide motion range of the order of several millimeters and yet achieve nanometric precision, resolution, and accuracy. In this paper, we highlight the several challenges that exist in the physical and control system design of a multi-axis flexure-based XY nanopositioning system capable of large dynamic range (~107). There are practical limitations associated with the individual physical components (flexure bearing, actuators, sensors, drivers, and microcontroller) as well as their integration. Once these physical system design challenges are overcome, the ensuing control system design challenges include non-***linear structural dynamics due to large deformation of the flexure bearing, non-collocated and multiple sensors and actuators, multiple sources of disturbance and noise, and classical closed-loop performance tradeoffs.