Three axis active magnetic levitation for inertial sensing systems

#This application is the U.S. national phase of international application PCT/CH2003/000597 filed 2 Sep. 2003 which designated the U.S. and claims benefit of PCT/CH02/00481, dated 2 Sep. 2002, the entire content of which is hereby incorporated by reference.

#The present invention relates to non-contact inertial sensing systems, that is to say inertial sensors where the inertial mass is never in contact with the rest of the instrument. The contact less suspension of said mass is assured by magnetic bearings.

#Current inertial sensing systems such as seismometers, accelerometers, gravimeters and tiltmeters are based on the relative displacement between an inertial mass and the base of the instrument when the said base is subject to an external disturbance (vibration, modification of the “g” level, angle); and gyroscopes, which are another kind of inertial sensing systems, are made of an inertial mass which is rotated about one of its axis of inertia and the measurement principle relies on the relative movement between the said axis and the base of the instrument, or on the force generated by the said axis on the base of the instrument, when the said base is subject to an external movement.

#For a greater understanding of the nature and objects of the invention, reference should be made to the following detailed description and the accompanying drawings, in which:

#FIG. 1 shows complete view of the first embodiment of the inertial sensing system with: 1) End cap 2) Support structure 3) Horizontal pair of electromagnets 4) Vertical pair of electromagnets 5) Ferromagnetic inertial mass 6) Holding structure for the horizontal electromagnets 7) High precision position sensors 8) Coil armature

#FIG. 2 shows a horizontal cut (O,X,Y) of the first embodiment of the inertial sensing system with: 3a), 3b), 3c), 3d) Coils 7a), 7b), 7c), 7d) High precision position sensors

#Implementation 1a (FIG. 1, FIG. 2, FIG. 3)

#Six electromagnets 3, 4, 3a, 3b, 3c, 3d are diametrically disposed in pairs along three orthogonal axis.

#A small size ferromagnetic inertial mass 5 is levitated and its position controlled along three axis.