Implementation of the control strategy for a 2D nanopositioning long range stage

A 2D-platform stage able to obtain an effective metrological positioning with nanometer resolution and long working range (50 x 50 mm2) is on development at the University of Zaragoza. The 2D stage has already been designed, manufactured and assembled. The movement of the platform is performed by four custom-made linear motors, and mirror laser interferometers work as positioning sensors in XYRz degrees of freedom. The work here presented focuses on the hardware implementation of the motor control, for one actuator on a 1D linear stage. The developed control strategy acts on three-phase PWM (Pulse-Width Modulation) signals and a feedback is provided by measuring the phase currents. As a preliminary solution, a sensorless algorithm substitutes the positioning sensor before implementing the laser interferometers.