Abstract: The invention provides a resonant sensor comprising: a substrate; one or more proof masses suspended from the substrate to allow for movement of the one or more proof masses along a sensitive axis; a first resonant element having a first end and a second end, the first resonant element extending between the first end and the second end along the sensitive axis, wherein the first end is connected to the one or more proof masses through a non-inverting lever and the second end is connected to the one or more proof masses through an inverting lever; and an electrode assembly positioned adjacent to the first resonant element. A resonant sensor in accordance the invention comprises a resonant element that is suspended between two proof masses or between two portions of a single proof mass, and so is not connected directly to the substrate. This isolates the resonant element from thermal stress that might otherwise be transferred from the substrate.

Abstract: A method of tuning a vibratory gyroscope, the method comprising the steps of: a) applying an AC drive signal to the drive electrode, the drive signal comprising a plurality of frequencies; b) sensing the response of the resonator to the drive signal at the first and second sense electrodes; c) determining a frequency of maximum response for the first mode of vibration, and determining a frequency of maximum response for the second mode of vibration; d) deriving a comparison result from a comparison of the frequency of maximum response for the first mode of vibration with the frequency of maximum response for the second mode of vibration; and e) applying a biasing voltage to one or more of the tuning electrodes dependent on the comparison result.

Abstract: There is provided an energy harvester for harvesting energy from broadband ambient vibrations comprising: a bi-stable oscillator, a subsidiary oscillator mechanically coupled to the bi-stable oscillator; wherein the bi-stable oscillator has a snap through frequency, ?snap, as a result of the ambient vibrations, and wherein the subsidiary oscillator exhibits resonance when driven at a frequency of ?snap; and at least one transducer coupled either to the bi-stable oscillator or to the subsidiary oscillator. This arrangement allows for resonant vibrational energy harvesting for be achieved over a broadband of input vibration frequencies.

Abstract: An apparatus is provided for harvesting energy from mechanical vibrations with an improved power output. The apparatus comprises a frame (22), a first member (20) comprising a piezoelectric material, a cantilever beam (26) and an electrode. The first member is fixed to the frame at a first position and a second position and extends between the first and second positions. The cantilever beam has a first end fixed to the first member between the first position and the second position and a second end fixed to a proof mass (24). The electrode is fixed to the first member at a position between the first position and the second position. In another aspect, the apparatus may comprise a plurality of proof masses connected to the first member between the first and second positions in a spaced relationship to one another.

Abstract: The invention provides a resonant sensor comprising: a substrate; one or more proof masses suspended from the substrate to allow for movement of the one or more proof masses along a sensitive axis; a first resonant element having a first end and a second end, the first resonant element extending between the first end and the second end along the sensitive axis, wherein the first end is connected to the one or more proof masses through a non-inverting lever and the second end is connected to the one or more proof masses through an inverting lever; and an electrode assembly positioned adjacent to the first resonant element. A resonant sensor in accordance the invention comprises a resonant element that is suspended between two proof masses or between two portions of a single proof mass, and so is not connected directly to the substrate. This isolates the resonant element from thermal stress that might otherwise be transferred from the substrate.

Abstract: A method of tuning a vibratory gyroscope, the gyroscope comprising: an axisymmetric disc resonator, a frame, the resonator fixed to the frame through at least three separate anchors, a plurality of electrodes, each electrode positioned on the frame or the resonator, wherein the plurality of electrodes comprises at least one drive electrode through which a drive signal is input to excite a first mode of vibration of the resonator, at least one first sense electrode configured to sense the first mode of vibration of the resonator, at least one second sense electrode configured to sense a second mode of vibration of the resonator, orthogonal to the first mode, and at least first and second tuning electrodes to which DC biasing voltages may be applied, the method comprising the steps of: a) applying an AC drive signal to the drive electrode, the drive signal comprising a plurality of frequencies; b) sensing the response of the resonator to the drive signal at the first and second sense electrodes; c) determining

Abstract: An apparatus is provided for harvesting energy from mechanical vibrations with an improved power output. The apparatus comprises a frame (22), a first member (20) comprising a piezoelectric material, a cantilever beam (26) and an electrode. The first member is fixed to the frame at a first position and a second position and extends between the first and second positions. The cantilever beam has a first end fixed to the first member between the first position and the second position and a second end fixed to a proof mass (24). The electrode is fixed to the first member at a position between the first position and the second position. In another aspect, the apparatus may comprise a plurality of proof masses connected to the first member between the first and second positions in a spaced relationship to one another.

Abstract: An energy harvester is provided for harvesting energy, and in particular electrical energy from an input vibration such as an ambient vibration. The energy harvester comprises a first mechanical amplifier responsive to the input vibration and a second mechanical amplifier coupled to the first mechanical amplifier. At least one of the first and second mechanical amplifiers comprises a parametric resonator, and a power output of the energy harvester is generated by damping the second mechanical amplifier.

Abstract: An inertial sensor comprising: a frame; a proof mass suspended from the frame; a pair of first resonant elements electrically coupled to the proof mass, or to an intermediate component mechanically coupled to the proof mass, each first resonant element coupled to an opposite side of the proof mass to the other, the first resonant elements being substantially identical to one another and having substantially identical electrostatic coupling with the proof mass when the sensor is not accelerating; wherein the first resonant elements and proof mass lie substantially in a plane, and wherein movement of the proof mass relative to the first resonant elements orthogonal to the plane alters the electrostatic coupling between the proof mass and the first resonant elements; drive means coupled to the first resonant elements for vibrating each of the first resonant elements; and a sensor assembly for detecting a shift in the resonant frequency of each of the first resonant elements; and processing means for summing the

Abstract: An inertial sensor comprising: a frame; a proof mass suspended from the frame; a pair of first resonant elements electrically coupled to the proof mass, or to an intermediate component mechanically coupled to the proof mass, each first resonant element coupled to an opposite side of the proof mass to the other, the first resonant elements being substantially identical to one another and having substantially identical electrostatic coupling with the proof mass when the sensor is not accelerating; wherein the first resonant elements and proof mass lie substantially in a plane, and wherein movement of the proof mass relative to the first resonant elements orthogonal to the plane alters the electrostatic coupling between the proof mass and the first resonant elements; drive means coupled to the first resonant elements for vibrating each of the first resonant elements; and a sensor assembly for detecting a shift in the resonant frequency of each of the first resonant elements; and processing means for summing the

Abstract: An energy harvester is provided for harvesting energy, and in particular electrical energy from an input vibration such as an ambient vibration. The energy harvester comprises a first mechanical amplifier responsive to the input vibration and a second mechanical amplifier coupled to the first mechanical amplifier. At least one of the first and second mechanical amplifiers comprises a parametric resonator, and a power output of the energy harvester is generated by damping the second mechanical amplifier.