Abstract: Embodiments herein relate to hollow profiles and methods of preparing the same for joining operations. A method herein can include placing a dam within a channel defined by the hollow profile, fitting a die block over an end of the channel, and injecting a flowable composition through an injection port into the channel. Another method can include defining a volume within a first member using at least one flow control device, filling the defined volume with a flowable polymeric composition, allowing the flowable polymeric composition to solidify to form a solid portion in the first member, and mechanically modifying the solid portion to define a joining surface suitable for joining to the second member. Other embodiments are also included herein.

Abstract: The disclosure describes techniques to damp the proof mass motion of an accelerometer while achieving an underdamped resonator. In an example of an in-plane micro-electromechanical systems (MEMS) VBA, the proof mass may contain one or more damping combs that include one or more banks of rotor comb fingers attached to the proof mass. The rotor comb fingers may be interdigitated with stator comb fingers that are attached to fixed geometry. These damping comb fingers may provide air damping for the proof mass when the MEMS die is placed into a package containing a pressure above a vacuum. The geometry of the damping combs with a reduced air gap and large overlap area between the rotor comb fingers and stator comb fingers. The geometry of resonator of the VBA of this disclosure may be configured to avoid air damping.

Abstract: An example system comprising: a microelectromechanical system (MEMS) vibrating beam accelerometer (VBA) comprising: a proof mass; and a first resonator mechanically coupled to the proof mass; a first electrode configured to apply a force to the proof mass.

Abstract: The disclosure describes techniques to adjust the geometry of a pendulous proof mass VBA to operate with sufficient signal-to-noise performance while avoiding nonlinear mechanical coupling at specified frequencies. The techniques of this disclosure include adding anchor support flexures to a resonator connection structure, adjusting shape, thickness, and the material of VBA components and of the VBA support structure to both control the frequency of any mechanical resonant modes and to adjust the mechanical mode frequencies away from desired operating frequencies and, in some examples, away from harmonics of desired operating frequencies.

Abstract: This disclosure describes techniques of configuring capacitive comb fingers of an accelerometer resonator into discreet electrodes with drive electrodes and at least two sense electrodes. The routing of electrical signals is configured to produce parasitic feedthrough capacitances that are approximately equal. The sense electrodes may be placed on opposite sides of the moving resonator beams such that the changes in capacitance with respect to displacement (e.g. dC/dx) are approximately equal in magnitude and opposite in sign. The arrangement may result in sense currents that are also opposite in sign and result in feedthrough currents of the same sign. The sense outputs from the resonators may be connected to a differential amplifier, such that the difference in output currents may mitigate the effect of the feedthrough currents and cancel parasitic feedthrough capacitance. Parasitic feedthrough capacitance may cause increased accelerometer noise and reduced bias stability.

Abstract: Systems and methods for suppressing bias in a non-degenerate vibratory structure are provided. In certain embodiments, a vibratory structure includes a first proof mass; a second proof mass, wherein the first proof mass and the second proof mass are driven into motion along a first axis, wherein the first proof mass and the second proof mass move in anti-phase along a second axis, wherein the motion of the first proof mass and the second proof mass along the second axis is such that the centers of mass of the first proof mass and the second proof mass move collinearly along a same axis.

Abstract: An example system comprising: a microelectromechanical system (MEMS) vibrating beam accelerometer (VBA) comprising: a proof mass; and a first resonator mechanically coupled to the proof mass; a first electrode configured to apply a force to the proof mass.

Abstract: This disclosure is related to devices, systems, and techniques for determining an acceleration of a vibrating beam accelerometer (VBA). For example, a system includes processing circuitry configured to receive, from a first resonator, one or more electrical signals indicative of a frequency of a first mechanical beam and a frequency of a second mechanical beam, determine, based on the one or more electrical signals, the frequency of the first mechanical beam and the frequency of the second mechanical beam, and calculate, based on the frequency of the first mechanical beam and the frequency of the second mechanical beam, an acceleration of a proof mass assembly.

Abstract: Embodiments herein relate to hollow profiles and methods of preparing the same for joining operations. A method herein can include placing a dam within a channel defined by the hollow profile, fitting a die block over an end of the channel, and injecting a flowable composition through an injection port into the channel. Another method can include defining a volume within a first member using at least one flow control device, filling the defined volume with a flowable polymeric composition, allowing the flowable polymeric composition to solidify to form a solid portion in the first member, and mechanically modifying the solid portion to define a joining surface suitable for joining to the second member. Other embodiments are also included herein.

Abstract: The disclosure describes techniques to damp the proof mass motion of an accelerometer while achieving an underdamped resonator. In an example of an in-plane micro-electromechanical systems (MEMS) VBA, the proof mass may contain one or more damping combs that include one or more banks of rotor comb fingers attached to the proof mass. The rotor comb fingers may be interdigitated with stator comb fingers that are attached to fixed geometry. These damping comb fingers may provide air damping for the proof mass when the MEMS die is placed into a package containing a pressure above a vacuum. The geometry of the damping combs with a reduced air gap and large overlap area between the rotor comb fingers and stator comb fingers. The geometry of resonator of the VBA of this disclosure may be configured to avoid air damping.

Abstract: This disclosure is related to devices, systems, and techniques for determining an acceleration of a vibrating beam accelerometer (VBA). For example, a system includes processing circuitry configured to receive, from a first resonator, one or more electrical signals indicative of a frequency of a first mechanical beam and a frequency of a second mechanical beam, determine, based on the one or more electrical signals, the frequency of the first mechanical beam and the frequency of the second mechanical beam, and calculate, based on the frequency of the first mechanical beam and the frequency of the second mechanical beam, an acceleration of a proof mass assembly.

Abstract: This disclosure describes techniques of configuring capacitive comb fingers of an accelerometer resonator into discreet electrodes with drive electrodes and at least two sense electrodes. The routing of electrical signals is configured to produce parasitic feedthrough capacitances that are approximately equal. The sense electrodes may be placed on opposite sides of the moving resonator beams such that the changes in capacitance with respect to displacement (e.g. dC/dx) are approximately equal in magnitude and opposite in sign. The arrangement may result in sense currents that are also opposite in sign and result in feedthrough currents of the same sign. The sense outputs from the resonators may be connected to a differential amplifier, such that the difference in output currents may mitigate the effect of the feedthrough currents and cancel parasitic feedthrough capacitance. Parasitic feedthrough capacitance may cause increased accelerometer noise and reduced bias stability.

Abstract: The disclosure describes techniques to adjust the geometry of a pendulous proof mass VBA to operate with sufficient signal-to-noise performance while avoiding nonlinear mechanical coupling at specified frequencies. The techniques of this disclosure include adding anchor support flexures to a resonator connection structure, adjusting shape, thickness, and the material of VBA components and of the VBA support structure to both control the frequency of any mechanical resonant modes and to adjust the mechanical mode frequencies away from desired operating frequencies and, in some examples, away from harmonics of desired operating frequencies.

Abstract: A vibrating beam accelerometer (VBA) with an in-plane translational proof mass that may include at least two or more resonators and be built with planar geometry, discrete lever arms, four-fold symmetry and a single primary mechanical anchor between the support base and the VBA. In some examples, the VBA of this disclosure may be built according to a micro-electromechanical systems (MEMS) fabrication process. Use of a single primary mechanical anchor may minimize bias errors that can be caused by external mechanical forces applied to the circuit board, package, and/or substrate that contains the accelerometer mechanism.

Abstract: A vibrating beam accelerometer (VBA) with an in-plane pendulous proof mass, which may include one or more resonators, planar geometry, a single primary mechanical anchor between the support base and the VBA, a resonator connector structure connecting the resonators to the single primary anchor and a hinge flexure mechanically connecting the proof mass to the single primary anchor. The techniques of this disclosure specify how the resonators can be solidly attached to the single anchor without compromising performance caused by forces applied on or by the support base. The geometry of the VBA may prevent bias errors that may otherwise result from a force applied to the support base that reaches the mechanism of the VBA. An example of force applied to the support base, may include the thermal expansion mismatch between the material of the support base and the material of the VBA.

Abstract: Systems and methods for suppressing bias in a non-degenerate vibratory structure are provided. In certain embodiments, a vibratory structure includes a first proof mass; a second proof mass, wherein the first proof mass and the second proof mass are driven into motion along a first axis, wherein the first proof mass and the second proof mass move in anti-phase along a second axis, wherein the motion of the first proof mass and the second proof mass along the second axis is such that the centers of mass of the first proof mass and the second proof mass move collinearly along a same axis.

Abstract: Systems and methods for suppressing bias in a non-degenerate vibratory structure are provided. In certain embodiments, a vibratory structure includes a first proof mass; a second proof mass, wherein the first proof mass and the second proof mass are driven into motion along a first axis, wherein the first proof mass and the second proof mass move in anti-phase along a second axis, wherein the motion of the first proof mass and the second proof mass along the second axis is such that the centers of mass of the first proof mass and the second proof mass move collinearly along a same axis.

Abstract: A vibrating beam accelerometer (VBA) with an in-plane translational proof mass that may include at least two or more resonators and be built with planar geometry, discrete lever arms, four-fold symmetry and a single primary mechanical anchor between the support base and the VBA. In some examples, the VBA of this disclosure may be built according to a micro-electromechanical systems (MEMS) fabrication process. Use of a single primary mechanical anchor may minimize bias errors that can be caused by external mechanical forces applied to the circuit board, package, and/or substrate that contains the accelerometer mechanism.

Abstract: A vibrating beam accelerometer (VBA) with an in-plane pendulous proof mass, which may include one or more resonators, planar geometry, a single primary mechanical anchor between the support base and the VBA, a resonator connector structure connecting the resonators to the single primary anchor and a hinge flexure mechanically connecting the proof mass to the single primary anchor. The techniques of this disclosure specify how the resonators can be solidly attached to the single anchor without compromising performance caused by forces applied on or by the support base. The geometry of the VBA may prevent bias errors that may otherwise result from a force applied to the support base that reaches the mechanism of the VBA. An example of force applied to the support base, may include the thermal expansion mismatch between the material of the support base and the material of the VBA.

Abstract: Systems and methods for noise and drift calibration using dithered calibration, a system comprising a processing unit; and two or more dithered calibrated sensors that provide directional measurements to the processing unit, wherein a dithered calibrated sensor in the dithered calibrated sensors has an input axis that rotates about an axis such that bias error can be removed by the processing unit; wherein the dithered calibrated sensor provides a zero-bias measurement along a first axis and a low-noise measurement along a second axis, the second axis being orthogonal to the first axis; wherein the dithered calibrated sensors are arranged such that the dithered calibrated sensor provide low-noise and zero-bias measurements along the measured axes; and wherein the processing unit executes an algorithm to combine measurements that are along the same axis to produce a measurement for each measured axis that has both low-noise and zero-bias.