Force balanced instrument system and method for mitigating errors
First Claim
1. A force balanced instrument system that employs charge pulses to null an inertial proof mass disposed between opposing electrode plates, the system comprising:
- an inertial proof mass disposed between a first electrode plate and a second electrode plate;
a switching system switchable between providing one of a positive charge pulse and a negative charge pulse to one of the first electrode plate and the second electrode plate; and
a control logic device that controls the switching of the switch system to provide positive charge pulses alternately to the first electrode plate and the second electrode plate for a first charge cycle time period and to provide negative charge pulses alternately to the first electrode plate and the second electrode plate for a second charge cycle time period.
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Accused Products
Abstract
A force balanced instrument system and method for mitigating errors is provided. The system and method mitigate errors in measurement readings caused by charge buildup in force balanced instruments that employ charge pulses to generate an electrostatic force to null an inertial proof mass disposed between opposing electrodes. The system and method mitigate charge buildup by applying positive charge pulses alternately to each opposing electrode for a given charge cycle time period followed by negative charge pulses alternately to each opposing electrode for a second given charge cycle time period. The negative charge pulses remove any residual charge on the electrodes caused by the positive charge pulses. As a result the net residual charge left on the electrodes is reduced on the average.
21 Citations
27 Claims
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1. A force balanced instrument system that employs charge pulses to null an inertial proof mass disposed between opposing electrode plates, the system comprising:
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an inertial proof mass disposed between a first electrode plate and a second electrode plate;
a switching system switchable between providing one of a positive charge pulse and a negative charge pulse to one of the first electrode plate and the second electrode plate; and
a control logic device that controls the switching of the switch system to provide positive charge pulses alternately to the first electrode plate and the second electrode plate for a first charge cycle time period and to provide negative charge pulses alternately to the first electrode plate and the second electrode plate for a second charge cycle time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A force balanced instrument having an inertial proof mass disposed between a first electrode plate and a second electrode plate, the instrument comprising;
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means for providing one of positive charge pulses and negative charge pulses;
means for applying charge pulses of a selected polarity alternately to the first electrode plate and the second electrode plate; and
means for controlling a charge cycle time period for applying positive charge pulses and a charge cycle time period for applying negative charge pulses by the means for applying. - View Dependent Claims (14, 15, 16, 17, 18, 19)
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20. A method for mitigating error in a force balanced instrument that employs charge pulses to null an inertial proof mass disposed between a first electrode plate and a second electrode plate, the method comprising:
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applying a charge pulse of a first polarity alternately to the first electrode plate and the second electrode plate for a first charge cycle time period;
determining a first difference voltage between voltages induced by the charge pulses of the first polarity on the first electrode plate and the second electrode plate for each charge cycle sequence of the first charge cycle time period;
aggregating the first difference voltage over time to set a duty cycle associated with the charge cycle sequence of the first charge cycle time period;
switching the polarity of the charge pulse to charge pulses of a second polarity after completion of the first charge cycle time period;
applying a charge pulse of the second polarity alternately to the first electrode plate and the second electrode plate for a second charge cycle time period;
determining a second difference voltage between voltages induced by the charge pulses of the second polarity on the first electrode plate and the second electrode plate for each charge cycle sequence of the second charge cycle time period; and
aggregating the second difference voltage over time to set a duty cycle associated with the charge cycle sequence of the second charge cycle time period. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27)
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Specification