Non contacting electro-pneumatic servo for vibration isolation
AssigneeTechnical Manufacturing Corporation
InventorGeoffrey L. Greene
Life of this patent
Estimating the term…
Abstract
A sensing system for a vibration isolation table. A sensor responsive to the position of the tabletop is spaced apart from the tabletop and provides an output corresponding to the position of the tabletop. The output is modified to provide a control signal and a valve responsive to the modified signal controls the flow of air into and out of an air isolator which supports the load.
Claims11
An apparatus for monitoring and controlling the position of a pneumatically supported load which load is supported by an air isolator which comprises:
- a sensor adapted to provide a sensor signal corresponding to the position of the supported load the sensor signal varying depending upon the position of the supported load;
- means to process the sensor signal and to provide a modulated, two-state, pulsed output signal at a modulation frequency, the duty cycle of the output signal determined by the sensor signal;
- a two-state pneumatic valve actuated by the output signal such that there is a net flow of air into or out of the isolator when the load is not at its zero position, whereby as the load moves to its zero position the net flow of air into or out of the air isolator decreases;
- and
- means to control the modulation frequency such that it is higher than the resonant frequency of the free mass/pneumatic system to ensure that the isolated mass responds only to the net gas flow averaged over many alternation cycles and does not respond to the input and output which occurs in the course of each cycle.
A method for monitoring and controlling the postion of a pneumatically supported load which load is supported by at least one air isolator and wherein a sensor is in communication with a valve which controls the flow of gas into and out of the air isolator which includes:
- sensing the position of the supported load;
- providing a signal from the sensor corresponding to the position of the supported load;
- processing the signal to provide a modulated, two-state pulsed output signal at a modulation frequency its duty cycle determined by the sensor signal;
- controlling the net flow of the air into or out of the air isolator by the output signal actuating a two-state pneumatic valve, the net flow of air into or out of the isolator occurring when the load is not at its zero position the net flow of air decreasing as the load moves to its zero position;
- and
- controlling the modulation frequency such that it is higher than the resonant frequency of the free mass/pneumatic system to ensure that the isolated mass responds only to the net gas flow averaged over many alternation cycles and does not respond to the input and output which occurs in the course of each cycle.
Dependencies are inferred from the claim text.