Introduction

1. Laser Klin Substrate CD capacity: 650 megabyte Air bearings K DVD capacity: 4.7 gigabyte Ultra high precision accuracy rotating active magnetic bearing Peter Overschie Delft University of Technology PME-Advanced Mechatronics Mekelweg 2 , 2628 CD Delft The Netherlands Tel: +31 15 2783142 Email: P.M.Overschie@TUDelft.nl Introduction Goal: Increase the information density of the optical storage media: CD: 0.6 GB  DVD: 4.7 GB  Blu-Ray25 GB! Objective Blu-Ray specs: Laser positioning error 1 nm (1sat 9000 rpm) New concept: Active Magnetic suspension. (picture on bottom) • The rotor is floating and spinning ‘vibration free’. • It is positioned by actuators on a force frame • The rotor position is measured sensors on a separate metrology frame. • MIMO control minimally activates the actuators. • Actuators and motor have a low stiffness to reduce the influence of floor vibrations. CD/DVD- Mastering device: current state of the art Magnetization Approach Specifications can only be met by optimizing components within their closed loop system: Development of power amplifier for our specific needs Controller design to deal with non-linearities in the actuators. Power Electronics Ansys modeling to study the magnetic properties of the motor Permanent magnets rotor Iron Peformance prediction by estimating the contributions of main disturbances to the rotor position accuracy: Actuators Control FEM of the rotor to develop dynamic Matlab models Mechatronic Approach Sensor Electronics Rotor Capacitive sensors, with an accuracy of 0.2 nm up to 1000 Hz Sensors Development of true 16 bit analog to digital converters, for accurate reading. Results Current Results: A positioning accuracy of 0.7 nm! (1 s ) has been achieved at standstill. Rotor Actuators Sensors Gravity Compensator • Future Research: • Motor implementation • Rotor Balancing and repetitive • error compensation Stator Motor