Application-Oriented Research Boosts Drive Technology: A Motor of Progress

New nanopositioning system based on magnetic levitation: the passive rod levitates on a magnetic field, which actively guides it. In this way, objects can be moved linearly or rotationally on a plane with a previously unattained guiding accuracy

In the coming years, sectors such as the semiconductor industry, life sciences or biotechnology will continue to grow. Increasing requirements in these sectors often affect supporting technologies. A typical example of this is found in drive technology: inspection and manufacturing systems in the semiconductor industry, for example, normally use air-bearing technology and magnetic linear motors.

However, the requirements for precision will continue to increase up into the nanometer range. Such systems also reach their limits when applications require work in a vacuum or nitrogen atmosphere. This issue has now been taken up by drive specialists, who have already achieved promising results with a new electromagnetic nanopositioning system.

When a feeling for markets, competence and teamwork ability come together, the user profits in the end. This is currently being proven by a cooperation of the Karlsruhe-based nanopositioning systems market leader PI (Physik Instrumente), the IMMS (Institut für Mikroelektronik- und Mechatronik-Systeme) and the Department of Mechatronics of Ilmenau University of Technology.

The result of their collaboration is a novel nanopositioning system based on the principle of magnetic levitation. The platform levitates on a magnetic field that is generated by six coils and is actively monitored via a 6-D sensor. The magnetic field functions as drive and actively guides the platform. The drive and the compact high-resolution measurement system for the six degrees of freedom was developed so that the platform remains passive, in other words no cable connections are necessary. A two-dimensional, optically incremental measurement system records the position with capacitive sensors and serves to control the drive in all axes. In this way, objects can be moved linearly or rotationally on a plane with a previously unattained guiding accuracy.

"The current, already quite advanced development study ‘PIMag 6D’ positions with a resolution of 10 nm," Dr Rainer Gloess, Head of Advanced Mechatronics at PI, is happy to announce. "If the system moves on a circular path with a diameter of 100 nm, for example, the maximum deviation from the ideal path is only a few nanometers."

The prototype currently has a motion range of 100mm³ x 100m³ x 0.15mm³. Trajectory motions can be carried out at an acceleration of up to 2m/s² and a velocity currently of up to 100mm/s with nanometer precision. The digital motion controller, based on a modular system from PI, can process different geometry files as well as coordinate transformations and offers an optimum basis for a successful new product line.

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