Abstract: An accelerometer includes an upper stator, a lower stator, and a proof mass assembly disposed between the upper and the lower stator. At least one of the upper stator or the lower stator includes an excitation ring, a magnet coupled to the excitation ring, and an asymmetric pole piece coupled to a top surface of the magnet. The asymmetric pole piece covers at least a portion of the top surface of the magnet such that a center of magnetic flux associated with the at least one of the upper stator or the lower stator is aligned with a center of mass of the proof mass assembly.

Abstract: Techniques of manufacturing an accelerometer as disclosed herein include positioning an accelerometer between a first stator and a second stator, and the accelerometer comprises a plurality of features. In some examples, the plurality of features include a proof mass, a support structure defining a plane and configured to support the proof mass, a flexure configured to flexibly connect the proof mass to the support structure, and a plurality of raised pads, the plurality comprising at least one raised pad positioned between the flexure and an exterior of the support structure, wherein the at least one raised pad is configured to be isolatable. Techniques of manufacturing the accelerometer as disclosed herein further include compressing the first stator and the second stator onto the accelerometer, attaching a bellyband to the first stator and the second stator, and isolating the at least one raised pad.

Abstract: Accelerometers as disclosed herein include a proof mass assembly and an accelerometer support. In some examples, a combined height and a combined coefficient of thermal expansion (CTE) of the materials of the accelerometer support is configured to substantially match a CTE of material of the non-moving member with a height substantially similar to the combined height of the accelerometer support. In some examples, the accelerometer support is configured to connect to a center raised pad of the proof mass assembly and maintain a capacitance gap between a capacitance plate on a proof mass of the proof mass assembly and a portion of the non-moving member.

Abstract: In some examples, the disclosure describes an accelerometer having improved hysteresis effects, the accelerometer including a proof mass assembly including a proof mass, a support structure, and a flexure flexibly connecting the proof mass to the support structure to allow the proof mass to move about the plane defined by the support structure. Some examples may include at least one thin film lead including an electrically conductive material on the flexure, where the at least one thin film lead provides an electrical connection between an electrical component on the support structure and an electrical component on the proof mass, and where the at least one thin film lead comprises at least one of a yield strength greater than pure gold or a thermal expansion coefficient less than pure gold.

Abstract: In some examples, a device comprises a proof mass and a support base configured to support the proof mass, wherein the proof mass is configured to displace in response to an acceleration of the device. The device also comprises a flexure configured to flexibly connect the proof mass to the support base. The device also comprises a strain-monitoring device configured to measure an amount of strain on the support base.

Abstract: Techniques of manufacturing an accelerometer as disclosed herein include positioning an accelerometer between a first stator and a second stator, and the accelerometer comprises a plurality of features. In some examples, the plurality of features include a proof mass, a support structure defining a plane and configured to support the proof mass, a flexure configured to flexibly connect the proof mass to the support structure, and a plurality of raised pads, the plurality comprising at least one raised pad positioned between the flexure and an exterior of the support structure, wherein the at least one raised pad is configured to be isolatable. Techniques of manufacturing the accelerometer as disclosed herein further include compressing the first stator and the second stator onto the accelerometer, attaching a bellyband to the first stator and the second stator, and isolating the at least one raised pad.

Abstract: Microelectromechanical (MEMS) accelerometer and acceleration sensing methods. An example MEMS accelerometer includes a housing, a proof mass suspended within the housing by at least one torsional flexure, at least one planar coil on the proof mass that extends on both sides of an axis of rotation of the proof mass, at least one magnet oriented such that a north-south axis of the at least one magnet is oriented approximately orthogonal to the rotational axis of the proof mass, at least one pole piece located outside the coil, and at least one magnetic flux concentrator located inside the coil opposite the at least one of the at least one pole pieces. A method includes sensing a change in capacitance of a pickoff in the MEMS accelerometer and rebalancing the MEMS accelerometer by sending a current through the planar coil between the magnetic flux concentrator and the pole piece.

Abstract: An accelerometer device having a proof mass, a support base, a hinge that flexibly connects the proof mass to the support base, a double-ended fork (DETF) having two tines. The tines are made of only piezoelectric material. A plurality of electrode surfaces surround at least portions of the tines for inducing electric fields at the first tine is opposite a direction of the induced electric field at the second tine at similar locations along a longitudinal axis of the tines. This causes the tines to resonate in-plane and out of phase.

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: 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: An in-plane, closed-loop Micro Electro-Mechanical Systems (MEMS) accelerometer device with improved performance. An example MEMS device includes one or more components for generating a magnetic flux field perpendicular to a major plane of the device. The device includes substrates, a proof mass, spring elements that flexibly connect the proof mass to the substrate and constrain the proof mass to translate within the major plane of the device which corresponds to a major surface of the proof mass, a plurality of conductive traces located at a position on the proof mass proximate the magnetic flux field, a plurality of conductive springs, each of the springs are electrically connected to a corresponding one of the conductive traces, and a plurality of anchor pads connected to the substrate and one of the conductive springs.

Abstract: An in-plane Micro Electro-Mechanical Systems (MEMS) accelerometer device with improved performance. An example MEMS device includes one or more components for generating a magnetic flux field perpendicular to a major plane. The device also includes a substrate, a proof mass, a hinge element that flexibly connects the proof mass to the substrate, the major plane corresponds to a major surface of the proof mass, a plurality of conductive leads located at a position on the proof mass proximate the magnetic flux field, a plurality of conductive springs, each of the springs are electrically connected to a corresponding one of the conductive leads, and a plurality of anchor pads connected to the substrate and one of the conductive springs. Isolation trenches directly connect to outer edges of the leads that are adjacent to other leads or proof mass material. The leads and springs include a plurality of slots.

Abstract: An accelerometer device having a proof mass, a support base, a hinge that flexibly connects the proof mass to the support base, a double-ended fork (DETF) having two tines. The tines are made of only piezoelectric material. A plurality of electrode surfaces surround at least portions of the tines for inducing electric fields at the first tine is opposite a direction of the induced electric field at the second tine at similar locations along a longitudinal axis of the tines. This causes the tines to resonate in-plane and out of phase.

Abstract: A translational, Micro-Electro-Mechanical System (MEMS) accelerometer device with precisely formed pole pieces to guide magnetic flux through a coil in a MEMS device layer. An example device includes a device layer, a magnetic return path component attached to a first side of the device layer, and a magnet unit attached to a second side of the device layer. The device layer includes a proof mass with electrically conductive trace and frame components. The magnet unit includes two magnetically conductive posts (formed of a ferrous material) located proximate to the trace, a base section formed of the same material as the posts, a non-magnetically conductive post (formed of a glass substrate) connected between the conductive posts, and a magnet attached to the non-magnetically conductive post within a cavity formed in the base section between the two magnetically conductive posts.

Abstract: Microelectromechanical (MEMS) accelerometer and acceleration sensing methods. A MEMS accelerometer includes a housing, a proof mass suspended within the housing by at least one torsional flexure, and a torsional magnetic rebalancing component. In an example embodiment, the torsional magnetic rebalancing component includes at least one planar coil on the proof mass that extends on both sides of an axis of rotation of the proof mass about the at least one torsional flexure and at least one magnet oriented such that a north-south axis of the at least one magnet is oriented approximately orthogonal to the rotational axis of the proof mass. A method includes sensing a change in capacitance of a pickoff in the MEMS accelerometer and rebalancing the MEMS accelerometer by sending a current through the planar coil.

Abstract: Microelectromechanical (MEMS) accelerometer and acceleration sensing methods. A MEMS accelerometer includes a proof mass suspended by at least one hinge type flexure, at least one planar coil located on the proof mass, and at least one magnet positioned such that a magnetic flux field passes through the at least one planar coil at an angle between approximately 30 degrees and approximately 60 degrees relative to the coil plane. In an example embodiment, the angle is approximately 45 degrees. The at least one magnet may include a first annular magnet positioned on a first side of the proof mass and a second annular magnet positioned on a second side of the proof mass. A method includes sensing a capacitance of a pickoff in the MEMS accelerometer and rebalancing the MEMS accelerometer by sending a current through the planar coil.

Abstract: Microelectromechanical (MEMS) accelerometer and acceleration sensing methods. A MEMS accelerometer includes a proof mass, a planar coil on the proof mass, a magnet, a first pole piece positioned proximate a first side of the proof mass, and a second pole piece positioned proximate a second side of the proof mass. A magnetic flux field passes from the magnet, through the first pole piece, through the planar coil at an angle between approximately 30 degrees and approximately 60 degrees relative to the coil plane, and into the second pole piece. The first pole piece may extend into a first recessed area of a first housing layer and the second pole piece may extend into a second recessed area of a second housing layer. A method includes sensing a capacitance of a pickoff in the MEMS accelerometer and rebalancing the MEMS accelerometer by sending a current through the planar coil.

Abstract: Systems and methods for minimizing vibration rectification error in magnetic circuit accelerometers. The systems include an accelerometer with an excitation ring that has a top piece with a lower portion inner diameter and a bottom piece having a diameter smaller than the lower portion inner diameter of the top piece. The accelerometer also includes a proof mass, a magnet mounted to the bottom piece of the excitation ring, a pole piece mounted to the magnet, and a coil attached to the proof mass that extends into a gap between the top piece of the excitation ring and the pole piece. The methods include placing a pole piece in a pole piece to lap surface fixture, placing an excitation ring top piece on an outer portion of the pole piece to lap surface fixture, and placing an excitation ring bottom piece in a lower portion of the excitation ring top piece.

Abstract: An in-plane, closed-loop Micro Electro-Mechanical Systems (MEMS) accelerometer device with improved performance. An example MEMS device includes one or more components for generating a magnetic flux field perpendicular to a major plane of the device. The device includes substrates, a proof mass, spring elements that flexibly connect the proof mass to the substrate and constrain the proof mass to translate within the major plane of the device which corresponds to a major surface of the proof mass, a plurality of conductive traces located at a position on the proof mass proximate the magnetic flux field, a plurality of conductive springs, each of the springs are electrically connected to a corresponding one of the conductive traces, and a plurality of anchor pads connected to the substrate and one of the conductive springs.

Abstract: An in-plane Micro Electro-Mechanical Systems (MEMS) accelerometer device with improved performance. An example MEMS device includes one or more components for generating a magnetic flux field perpendicular to a major plane. The device also includes a substrate, a proof mass, a hinge element that flexibly connects the proof mass to the substrate, the major plane corresponds to a major surface of the proof mass, a plurality of conductive leads located at a position on the proof mass proximate the magnetic flux field, a plurality of conductive springs, each of the springs are electrically connected to a corresponding one of the conductive leads, and a plurality of anchor pads connected to the substrate and one of the conductive springs. Isolation trenches directly connect to outer edges of the leads that are adjacent to other leads or proof mass material. The leads and springs include a plurality of slots.