Magnetic Levitation Technology Demonstrator for Nanopositioning Applications

The basic principle of magnetic levitation is that like magnetic poles repel each other. To achieve magnetic levitation in its most simple form, two magnets are used; one magnet is placed in the object that needs to be levitated, and the other magnet is placed beneath it.

To make this principle useful for precision motion control, for example in linear stages, the magnets in the base must be electrically controllable coils and it takes more than just a pair to also control lateral motion, vertical motion and pitch, yaw, and roll. In many practical implementations, Hallbach arrays are used to minimize the energy consumption, increase the load capacity, and reduce thermal energy dissipation.

A position sensing system is also required to provide feedback to the motion controller. Since no mechanical bearings restrict the motion of the linear stage platform to precisely one degree of freedom, a powerful, high-bandwidth multi-axis controller is required to keep all other degrees of freedom in check.   

While this seems complicated, the benefits can be huge. Not being limited by a mechanical bearing adds an incredible amount of freedom to electronically correct bearing insufficiencies. It also allows for controlled small angular motions, e.g., to align a sample perfectly with an optics or camera or chip without the need for adding a bulky theta stage to the linear stage. In addition, vertical motions can be programmed, very useful for precise focusing. 

PI has been investing in research on magnetic levitation for nanopositioning applications and will work with customers to move the technology forward together. A technology demonstrator is available at PI’s Silicon Valley tech center.