SYSTEMS AND METHODS FOR EXTRACTING SYSTEM PARAMETERS FROM NONLINEAR PERIODIC SIGNALS FROM SENSORS
Systems and methods are disclosed herein for extracting system parameters from nonlinear periodic signals from sensors. A sensor such as an inertial device includes a first structure and a second structure that is springedly coupled to the first structure. The sensor is configured to generate an output voltage based on a current between the first and second structures. Monotonic motion of the second structure relative to the first structure causes a reversal in direction of the current.
1 - 30 . (canceled)
31 . An inertial device, comprising:
a fixed element comprising a first plurality of beams that are spaced along a first axis;
a first plurality of teeth, adjacent teeth of which are equally spaced along a second axis perpendicular to the first axis, each of the first plurality of teeth disposed on a respective beam of the first plurality of beams;
a moveable element comprising a second plurality of beams that are spaced along the first axis, the moveable element configured to move relative to the fixed element along the second axis;
a second plurality of teeth, adjacent teeth of which are equally spaced along the second axis, each of the second plurality of teeth disposed on a respective beam of the second plurality of beams; and
circuitry configured to:
generate an output signal based on a capacitance between the fixed and movable elements,
determine time intervals based on comparing the output signal to a threshold, and
determine an acceleration of the inertial device based on the time intervals.
32 . The inertial device of claim 31 , further comprising:
a voltage source configured to apply a constant voltage between the fixed and moveable elements; and
a drive unit configured to drive the moveable element in oscillatory motion relative to the fixed element; and
wherein the oscillatory motion of the moveable element relative to the fixed element results in oscillations in the capacitance.
33 . The inertial device of claim 32 , wherein:
acceleration of the inertial device results in a first offset in the oscillations in the capacitance; and
the first offset of the oscillations in the capacitance results in changes to the time intervals.
34 . The inertial device of claim 31 , further comprising:
a voltage source configured to apply an oscillatory voltage between the fixed and moveable elements;
wherein the oscillatory voltage results in oscillations in the current.
35 . The inertial device of claim 34 , wherein:
acceleration of the inertial device results in a first offset in the oscillations in the capacitance; and
the first offset of the oscillations in the capacitance results in changes to the time intervals.
36 . The inertial device of claim 31 , wherein the moveable element is springedly coupled to the fixed element.
37 . The inertial device of claim 31 , further comprising a drive unit configured to oscillate the moveable element relative to the fixed element.
38 . The inertial device of claim 31 , wherein:
monotonic motion of a first tooth of the first plurality of teeth past an aligned position with a second tooth of the second plurality of teeth causes a nonmonotonic change the capacitance.
39 . The inertial device of claim 31 , wherein:
the output signal is a digital signal; and
the circuitry is configured to generate the output signal by:
determining an analog signal based on the capacitance,
comparing the capacitance to a threshold, and
changing, based on the comparison, the output signal from a first value to a second value.
40 . The inertial device of claim 39 , wherein the circuitry is further configured to:
determine, based on comparing the analog signal to a plurality of thresholds, that the analog signal crosses one of the plurality of thresholds; and
change, based on the determining that the output voltage has crossed one of the plurality of thresholds, the output signal from the first value to the second value.
41 . The inertial device of claim 40 , wherein the circuitry is configured to:
determine a time between the changing of the output signal and a subsequent changing of the output signal,
based on the determined time, determine the acceleration of the inertial device, and
based on the acceleration, output an acceleration signal.
42 . The inertial device of claim 31 , wherein the motion of the moveable element relative to the fixed element is along the second axis.
43 . The inertial device of claim 31 , wherein the nonmonotonic change in capacitance occurs due to alignment of the first and second pluralities of teeth.
44 . The inertial device of claim 31 , wherein the nonmonotonic change in capacitance occurs due to anti-alignment of the first and second pluralities of teeth.
45 . The inertial device of claim 32 , wherein the drive unit is further configured to:
receive the output signal; and
based on the received output signal, adjust the oscillatory motion of the moveable element relative to the fixed element.
46 . The inertial device of claim 31 , wherein:
centers of adjacent teeth of the first plurality of teeth are separated by a first pitch distance; and
centers of adjacent teeth of the second plurality of teeth are separated by the first pitch distance.
47 . The inertial device of claim 31 , wherein:
centers of adjacent beams of the first plurality of beams are separated by a second pitch distance; and
centers of adjacent beams of the second plurality of beams are separated by the second pitch distance.
48 . A method, comprising:
generating an output signal based on a capacitance between the fixed and movable elements, wherein:
the fixed element comprises a first plurality of beams that are spaced along a first axis and a first plurality of teeth, adjacent teeth of which are equally spaced along a second axis perpendicular to the first axis, each of the first plurality of teeth disposed on a respective beam of the first plurality of beams,
the moveable element comprises a second plurality of beams that are spaced along the first axis, the moveable element configured to move relative to the fixed element along the second axis, and a second plurality of teeth, adjacent teeth of which are equally spaced along the second axis, each of the second plurality of teeth disposed on a respective beam of the second plurality of beams, and
determining time intervals based on comparing the output signal to a threshold; and
determining an acceleration of the method based on the time intervals.
49 . The method of claim 48 , further comprising:
applying a constant voltage between the fixed and moveable elements; and
driving the moveable element in oscillatory motion relative to the fixed element; and
wherein the oscillatory motion of the moveable element relative to the fixed element results in oscillations in the capacitance.
50 . The method of claim 49 , wherein:
acceleration of the method results in a first offset in the oscillations in the capacitance; and
the first offset of the oscillations in the capacitance results in changes to the time intervals.
51 . The method of claim 48 , further comprising:
applying an oscillatory voltage between the fixed and moveable elements;
wherein the oscillatory voltage results in oscillations in the current.
52 . The method of claim 51 , wherein:
acceleration of the method results in a first offset in the oscillations in the capacitance; and
the first offset of the oscillations in the capacitance results in changes to the time intervals.
53 . The method of claim 48 , wherein the moveable element is springedly coupled to the fixed element.
54 . The method of claim 48 , further comprising oscillating the moveable element relative to the fixed element.
55 . The method of claim 48 , wherein:
monotonic motion of a first tooth of the first plurality of teeth past an aligned position with a second tooth of the second plurality of teeth causes a nonmonotonic change the capacitance.
56 . The method of claim 48 , wherein
the output signal is a digital signal; and
generating the output signal comprises:
determining an analog signal based on the capacitance,
comparing the capacitance to a threshold, and
changing, based on the comparison, the output signal from a first value to a second value.
57 . The method of claim 56 , further comprising:
determining, based on comparing the analog signal to a plurality of thresholds, that the analog signal crosses one of the plurality of thresholds; and
changing, based on the determining that the output voltage has crossed one of the plurality of thresholds, the output signal from the first value to the second value.
58 . The method of claim 57 , further comprising:
determining a time between the changing of the output signal and a subsequent changing of the output signal,
based on the determined time, determining the acceleration of the method, and
based on the acceleration, outputting an acceleration signal.
59 . The method of claim 48 , wherein the motion of the moveable element relative to the fixed element is along the second axis.
60 . The method of claim 48 , wherein the nonmonotonic change in capacitance occurs due to alignment of the first and second pluralities of teeth.
61 . The method of claim 48 , wherein the nonmonotonic change in capacitance occurs due to anti-alignment of the first and second pluralities of teeth.
62 . The method of claim 49 , further comprising adjusting, based on the received output signal, the oscillatory motion of the moveable element relative to the fixed element.
63 . The method of claim 48 , wherein:
centers of adjacent teeth of the first plurality of teeth are separated by a first pitch distance; and
centers of adjacent teeth of the second plurality of teeth are separated by the first pitch distance.
64 . The method of claim 48 , wherein:
centers of adjacent beams of the first plurality of beams are separated by a second pitch distance; and
centers of adjacent beams of the second plurality of beams are separated by the second pitch distance.