Abstract: Systems and methods for improving common mode cancelation in a vibrating beam accelerometer (VBA) by using multiple resonant modes. The VBA includes two double-ended tuning forks (DETF). Additional oscillators drive the DETFs into the extra resonant modes. This increases common mode rejection from two modes to four modes. In addition the scale factor of the additional mode may provide a greater scale factor than prior designs.

Abstract: An accelerometer includes a base, a proof mass flexibly connected to the base, and a double-ended tuning fork (DETF) coupled to the proof mass and the base. The DETF includes a base attached to the accelerometer base, an outrigger that extends from a first side of the base, and two tines that extend from a side of the outrigger that is opposite the first side of the base. The accelerometer also includes a drive mechanism that generates opposing forces in different halves of the outrigger, thereby causing the tines to oscillate. An excitation voltage applied to metallized traces on the outrigger at the base of the DETF cause the tines to resonant. The alternating strains generated at the root of the tines excite the tines themselves at their resonant frequency without the requirement of complex metallization applied to the tines.

Abstract: Systems and methods for improving common mode cancelation in a vibrating beam accelerometer (VBA) by using multiple resonant modes. The VBA includes two double-ended tuning forks (DETF). Additional oscillators drive the DETFs into the extra resonant modes. This increases common mode rejection from two modes to four modes. In addition the scale factor of the additional mode may provide a greater scale factor than prior designs.

Abstract: An accelerometer includes a base, a proof mass flexibly connected to the base, and a double-ended tuning fork (DETF) coupled to the proof mass and the base. The DETF includes a base attached to the accelerometer base, an outrigger that extends from a first side of the base, and two tines that extend from a side of the outrigger that is opposite the first side of the base. The accelerometer also includes a drive mechanism that generates opposing forces in different halves of the outrigger, thereby causing the tines to oscillate. An excitation voltage applied to metallized traces on the outrigger at the base of the DETF cause the tines to resonant. The alternating strains generated at the root of the tines excite the tines themselves at their resonant frequency without the requirement of complex metallization applied to the tines.

Abstract: A magnetometer is integrated with a miniature vibrating beam accelerometer fabricated out of silicon on a common substrate. Dual pendulum-DETF force sensing accelerometers have integrated conductor coils on the pendulums that circulate alternating current to cause an additional pendulum motion also sensed by the DETF transducers for sensing local earth magnetic field. The integrated magnetic and acceleration sensing is used for each of three reference axes in a triaxial inclinometer magnetometer for borehole drill steering and surveying.

Abstract: A double-ended tuning fork (DETF) is formed from two vibrating beams joined together at each end, having a thickness t, a width w, a length L and a vibrating beam length m. The dimensional ratios t/w and L/m for the DETF are selected according to a relatively more accurate spurious mode map based upon detailed finite element calculations at specific dimensional ratios for t/w and L/m. The results of the finite element analysis is fit by way of a lease-squared polynomial over the entire dimensional range of interest. The results of the finite element analysis for the spurious modes provides differences of up to fourteen percent (14%) relative to the spurious mode map based on simple beam theory. In addition, the spurious mode map in accordance with the present invention accounts for the use of symmetric outriggers in the base region of the DETF which increases the mechanical Q of the DETF.

Abstract: An open top box structure is micromachined on a base, such as a crystalline silicon substrate, and drive and sensing devices are fabricated on the same substrate. Output transducers sense Coriolis force changes by processing signals representing force components at the corners of the vibrating box structure as it is rotated to yield angular rate measurement.

Abstract: A vibrating tine resonator having a unitary body cut from flat, planar crystalline stock includes spaced apart end portions and a tine system extending between said portions. The tine system includes a pair of similar tine arrays extending side-by-side between base portions. Each array includes a pair of tines extending parallel to one another and defining a slot separating each adjacent pair of tines. Each array also includes a bridge portion spanning the slot and joining the tines. The resonator is excited to operate in a dynamic mode including both a torsional motion component and also a normal motion component. The bridge portion interconnecting adjacent tines is pivoted around an axis parallel with the tines. The tines are also moved to vibrate in directions normal to the flat plane of the resonator body.

Abstract: A vibrating disc transducer assembly suitable for accurately measuring high pressures utilizes a transducer having a vibratory disc that is preferably fabricated from silicon and excited to vibrate in the thickness-shear mode. The excitation is accomplished by placing the resonator in a magnetic field and passing an electric current through electrodes on opposite sides of the disc. The transducer is supported in a housing that communicates with the medium whose pressure is being measured.