Control circuit for accelerometer
AssigneeLear Siegler, Inc.
InventorJohn R. Washburn
Life of this patent
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Abstract
A pendulously supported proof mass accelerometer wherein a pulse generator applies periodic pulses to a bridge circuit comprising variable resistors and pick-off capacitors to generate a restoring current to maintain the proof mass in a null position. The variable resistors of the bridge circuit provide a means of varying the null position of the proof mass to achieve substantially balanced linear operation of the accelerometer circuitry. A bias compensation circuit applies a correction current to an output circuit which is equal in magnitude and opposite in direction to output current produced by static bias factors of the accelerometer.
Claims22
An accelerometer adapted to measure magnitude and direction of an acceleration force externally applied thereto and comprising:
- an accelerometer housing assembly;
- indicating means pendulously supported within said housing assembly for indicating, via a positional displacement thereof, the occurrence of said acceleration force, wherein said indicating means is pendulously supported at a null position in the absence of said acceleration force;
- detection circuit means for detecting said positional displacement of said indicating means and for generating a restoring signal representative of the magnitude and direction of said positional displacement;
- restoring means coupled to said detection circuit means and responsive to said restoring signal for restoring said indicating means to said null position;
- output circuit means electrically coupled to said restoring means and comprising an output terminal for generating an output signal thereat indicative of the magnitude and direction of said externally applied acceleration force;
- and
- characterized in that
- said accelerometer further comprises bias compensation circuit means connected to said output terminal and selectively adjustable to apply a correction signal to said output circuit means, wherein said correction signal is of a substantially equal magnitude and opposite in direction to components of said output signal due to static bias factors.
In a method for measuring the magnitude and direction of an externally applied acceleration force wherein:
- a proof mass is maintained at a null position in the absence of said externally applied acceleration force;
- said proof mass is positionally displaced in response to said externally applied acceleration;
- a restoring signal indicative of the magnitude and direction of positional displacement of said proof mass is generated;
- said proof mass is restored to said null posiion in response to said restoring signal;
- and
- an output signal representative of the magnitude and direction of said restoring signal is generated;
- the improvement which comprises adjusting said null position of said proof mass to substantially minimize the generating of said output signal in response to vibrational motion of said proof mass;
- and
- adding to said output signal a correction signal component equal in magnitude and opposite in direction to a component of said output signal resultant from static bias factors of said accelerometer.
Dependencies are inferred from the claim text.