Measuring and testing – Speed – velocity – or acceleration – Acceleration determination utilizing inertial element
Patent
1985-12-20
1988-04-12
Chapman, John
Measuring and testing
Speed, velocity, or acceleration
Acceleration determination utilizing inertial element
73514, 324 60C, 324 61R, G01P 15125
Patent
active
047366290
ABSTRACT:
The accelerometer comprises a substrate (52), a metallic movable plate (50), and a mounting system (54) for mounting the movable plate such that it is positioned above the substrate and can rotate about a flexure axis (64) that is above and is substantially parallel to the substrate. The flexure axis divides the sensing element into first (66) and second (68) sections. The total moments of the first and second sections about the flexure axis are different, such that acceleration normal to the substrate tends to rotate the sensing element about the flexure axis. A first electrode (74) is mounted by the substrate adjacent the first section to form a first capacitor (C.sub.A), and a second electrode (76) is mounted by the substrate adjacent the second section to form a second capacitor (C.sub.B). A detector for measuring the relative capacitances of the first and second capacitors is provided comprising an integrator (166), an inverting amplifier (168), and switches (160, 162, 164) for periodically charging and discharging the capacitors in response to a clock signal. In one embodiment, the sensing element includes an internal opening (16, 56, 126) and the mounting system is positioned within the opening and includes a pedestal mounted to the substrate, and torsion bars (20, 22, 118, 120) and/or a beam (60, 114) connecting the pedestal to the sensing element. The sensing element preferably comprises a metallic plate, and the substrate preferably comprises a semiconductor upon which the detector and electrodes are fabricated in a single step process requiring no final assembly of components. In an embodiment adapted for high g applications, a pedestal (146) divides a plate member into first (148) and second (150) cantilevered beams that flex in the same direction in response to a given acceleration.
REFERENCES:
patent: 3226981 (1966-01-01), Mullins et al.
patent: 3355952 (1967-12-01), Romberg
patent: 3478604 (1969-11-01), Evans
patent: 3498138 (1970-03-01), Stewart
patent: 3528297 (1970-09-01), Lee
patent: 4306456 (1981-12-01), Maerfeld
patent: 4342227 (1982-08-01), Petersen et al.
patent: 4345474 (1982-08-01), Deval
patent: 4430895 (1984-02-01), Colton
patent: 4459849 (1984-07-01), Calamera
patent: 4483194 (1984-11-01), Rudolf
patent: 4598585 (1986-07-01), Boxenhorn
Corey, "Multi-Axis Clusters of Single-Axis Accelerometers with Coincident Centers of Angular Motion Insensitivity", presented at the 6th International Aerospace Symposium, Bedford, England, Mar. 23-26, 1970.
Chapman John
Silicon Designs, Inc.
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