ELECTROMAGNETIC SUPPORT DEPENDING UPON NO CURRENT

摘要

PURPOSE: To provide a positioning device of an object where stiffness and bandwidth do not depend on a current that flows through an electromagnet. CONSTITUTION: An object 5 is positioned by at least two electromagnets 13 and 15. A position sensor measures an air gap 23 between the electromagnets 13 and 15 and one guide beam 1. The output signal of the position sensor 29 is fed to an electronic control unit 35 for allowing a control current to flow to the electromagnets 13 and 15 according to the difference between the measured size and a desired size of the air gap 23. An electronic route extractor 37 is connected between the control unit 35 and the two electromagnets 13 and 15. The output signal of the route extractor 37 has a value that is equal to the square of a control signal from the control unit 35, thus enabling a force that is given to the guide beam 1 by the electromagnets 13 and 15 to be proportional to the value of the control signal.