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 detailled finite element calculations at specific dimensional ratios for t/w and L/m. The results of the finite element analysis are fit by way of a least-squared polynominal over the entire dimensional range of interest. The results of the finite element analysis for the spurious modes provide 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 in the base region outriggers in the base region of the DETF which increases the mechanical Q of the DETF.
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 magnetometer is integrated with a miniature vibrating beam accelerometer fabricated out of silicon on a common susbtrate. 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:
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 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 detailled finite element calculations at specific dimensional ratios for t/w and L/m. The results of the finite element analysis are fit by way of a least-squared polynominal over the entire dimensional range of interest. The results of the finite element analysis for the spurious modes provide 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 in the base region 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.