Electrostatic bearing sensing and control circuitry

Claim 2

In an electrostatic suspension, force-rebalance type inertial instrument in which the suspension plates of the electrostatic bearing are further used in a capacitive bridge to provide inertial data read-out, non-magnetic circuit means for decoupling the force rebalance signal component and the inertial data signal components.

Claim 3

The device of claim 1 in which said non-magnetic circuit means comprises electronic difference signalling means having a first input responsively coupled to said capacitive bridge and further a second input responsively coupled to an A-C force rebalance voltage source of said instrument compensatory gain scaling means interposed between said force rebalance voltage source and said second input of said difference signalling means, for simulating that force rebalance signal component occurring in the first input to said difference signalling means, whereby said component is cancelled in the output of said signal differencing means.

Claim 4

In an electrostatic bearing support circuit for supporting a rotatable member between a pair of electrodes and having electrostatic support means for establishing an A-C potential between said rotatable member and said electrodes for electrostatically supporting said rotatable member, sensing means for providing an A-C position signal which varies as a function of the position of said rotatable member with respect to said electrodes, inductance means inductively coupling said sensing means to said support means, the improvement of support signal cancellation means comprising electronic differential signalling means having a first input responsively connected across said inductance means and a second input coupled to a support voltage source of said supporting means; and signal attenuation means for preselectively attenuating the input voltage applied to said second input of said signalling means to provide a replica of the support voltage component drop across said inductance means.

Claim 5

In an electrostatic bearing support circuit for supporting a rotatable member between a pair of electrodes and having electrostatic support means for establishing an A-C potential between said rotatable member and said electrodes for electrostatically supporting said rotatable member, sensing means for providing an A-C position signal which varies as a function of the position of said rotatable member with respect to said electrodes, inductance means inductively coupling said sensing means to said support means, the improvement of support signal cancellation means comprising electronic differential signalling means having a first input responsively connected across said inductance means and a second input coupled to a support voltage source of said supporting means; and signal attenuation means for preselectively attenuating the input voltage applied to said second input of said signalling means to provide a replica of the support voltage component drop across said inductance means.

Claim 6

In an electrostatic suspension, force-rebalance type inertial instrument in which the suspension plates of the electrostatic bearing are further used in a capacitive bridge to provide position pickoff data read-out, non-magnetic circuit means for decoupling the force rebalance signal component and the pickoff position data signal components; said non-magnetic circuit means comprising electronic difference signalling means having a first input responsively coupled to said capacitive bridge and further a second input responsively coupled To an A-C force rebalance voltage source of said instrument, compensatory gain scaling means interposed between said force rebalance voltage source and said second input of said difference signalling means, for simulating that force rebalance signal component occurring in the first input to said difference signalling means, whereby said component is cancelled in the output of said signal differencing means; said instrument further including generating means responsive to said force rebalance voltage for generating a force rebalance alternating current substantially in time-phase quadrature with said force rebalance voltage, said current being fed to said capacity bridge by an inductive sensing and control circuit, said compensatory gain-scaling means comprising electronic feedback amplifying means.

Claim 7

In an electrostatic suspension, force-rebalance type inertial instrument in which the suspension plates of the electrostatic bearing are further used in a capacitive bridge to provide position pickoff data read-out, non-magnetic circuit means for decoupling the force rebalance signal component and the pickoff position data signal components; said non-magnetic circuit means comprising electronic difference signalling means having a first input responsively coupled to said capacitive bridge and further a second input responsively coupled To an A-C force rebalance voltage source of said instrument, compensatory gain scaling means interposed between said force rebalance voltage source and said second input of said difference signalling means, for simulating that force rebalance signal component occurring in the first input to said difference signalling means, whereby said component is cancelled in the output of said signal differencing means; said instrument further including generating means responsive to said force rebalance voltage for generating a force rebalance alternating current substantially in time-phase quadrature with said force rebalance voltage, said current being fed to said capacity bridge by an inductive sensing and control circuit, said compensatory gain-scaling means comprising electronic feedback amplifying means.

Claim 8

In an electrostatic bearing support circuit for supporting a rotatable member between a pair of electrodes and having electrostatic support means for establishing an A-C potential between said rotatable member and said electrodes for electrostatically supporting said rotatable member, sensing means for providing an A-C position signal which varies as a function of the position of said rotatable member with respect to said electrodes, inductance means inductively coupling said sensing means to said support means, the improvement of support signal cancellation means comprising electronic differential signalling means having a first input responsively connected across said inductance means and a second input coupled to a support voltage source of said supporting means; and signal attenuation means for preselectively attenuating the input voltage applied to said second input of said signalling means to provide a replica of the support voltage component drop across said inductance means; said support means including phase coding means for providing a co-phasal time-phase relation between the support voltage component drop across said inductance means and the position voltage drop thereacross.

Claim 9

In an electrostatic bearing support circuit for supporting a rotatable member between a pair of electrodes and having electrostatic support means for establishing an A-C potential between said rotatable member and said electrodes for electrostatically supporting said rotatable member, sensing means for providing an A-C position signal which varies as a function of the position of said rotatable member with respect to said electrodes, inductance means inductively coupling said sensing means to said support means, the improvement of support signal cancellation means comprising electronic differential signalling means having a first input responsively connected across said inductance means and a second input coupled to a support voltage source of said supporting means; and signal attenuation means for preselectively attenuating the input voltage applied to said second input of said signalling means to provide a replica of the support voltage component drop across said inductance means; said support means including phase coding means for providing a co-phasal time-phase relation between the support voltage component drop across said inductance means and the position voltage drop thereacross.