Optical table active leveling and vibration cancellation system

摘要

An optical table active leveling and vibration cancellation system is disclosed. The system includes an optical table with three active isolation devices connected to the optical table, and one sole pneumatic device, such that the table is supported on all four corners. Each of the isolation devices includes a pneumatic suspension device and an electromagnetic suspension device. The pneumatic suspension device includes a pressurized load chamber, a gimballed piston received in the pressurized load chamber and coupled to the walls of the pressurized load chamber by a thin walled diaphragm, and a support rod extending from the optical table to the floor level. The electromagnetic bearing suspension device includes a magnetic bearing rotor having two planar surfaces and a peripheral surface, and two magnetic bearing stators, the stators each defining a central aperture and each stator being in a spaced apart relationship from each of the rotor planar surfaces. The rotor is secured to the support rod. Each of the stators includes an annular coil of wire. The electromagnetic suspension system may also include four radial electromagnets spaced around the peripheral surface of the rotor. The radial electromagnets also include an annular coil of wire. The system also includes three proximity sensors mounted under the optical table to detect motion of the table in relation to the floor or another fixed reference, and generate a signal in response to the motion. The system also includes three accelerometers mounted underneath the optical table in a triangle. The accelerometers measure vibration of the table in relation to inertial space and generate a signal in response to the movement. A controller receives the signals from the sensors and accelerometers, and generates a second signal, used to activate the pneumatic and electromagnetic bearing suspension devices to provide active leveling and vibration cancellation of the optical table.