Elevator cab floor acceleration control system

An elevator comprising:

• a frame supported by a moveable rope for vertical motion between a pair of guide rails;
• a cab having a platform and supported solely by compliant sound isolation devices disposed between said frame and said platform, said platform being moveable with respect to said frame as a consequence of deformation of said isolation devices;
• a pair of electromagnets disposed in fixed relation to one of said platform and said frame;
• a pair of magnet reaction objects disposed in fixed relation to the other one of said platform and said frame with an air gap disposed between each reaction objects and a corresponding one of said electromagnets, wherein each said set of air gap, reaction object and electromagnet complete a magnetic circuit for a magnetic field generated by the corresponding electromagnet, the magnetic field of one of said sets being parallel to the magnetic field of the other of said sets along a first axis, said electromagnets and magnet reaction objects being disposed so that one of said magnetic fields will move said platform in one direction along said axis and the other of said magnetic fields will move said platform in a direction opposite to said one direction;
• an acceleration sensor disposed in fixed relation to said platform, said acceleration sensor generating an acceleration signal indicative of acceleration of the elevator cab platform in a direction parallel to the magnetic fields extending across said air gaps;
• and
• a controller responsive to said acceleration signal to vary the strength of the magnetic fields generated by each of said electromagnets to provide bi-directional control of acceleration of said platform.