Patent classifications
G01C19/5755
MEMS GYROSCOPE WITH CALIBRATION OF THE SCALE FACTOR IN REAL TIME AND CALIBRATION METHOD THEREOF
The MEMS gyroscope has a mobile mass carried by a supporting structure to move in a driving direction and in a first sensing direction, perpendicular to each other. A driving structure governs movement of the mobile mass in the driving direction at a driving frequency. A movement sensing structure is coupled to the mobile mass and detects the movement of the mobile mass in the sensing direction. A quadrature-injection structure is coupled to the mobile mass and causes a first and a second movement of the mobile mass in the sensing direction in a first calibration half-period and, respectively, a second calibration half-period. The movement-sensing structure supplies a sensing signal having an amplitude switching between a first and a second value that depend upon the movement of the mobile mass as a result of an external angular velocity and of the first and second quadrature movements. The first and second values of the sensing signal are subtracted from each other and compared with a stored difference value to supply information of variation of the scale factor.
BANDWIDTH EXTENSION FOR CONTINUOUS MODE REVERSAL GYROSCOPE
A vibratory gyroscope system having a mechanical resonator (proof mass) and drive circuitry for maintaining oscillation in two axes at a small frequency split. Angular rate input is shifted to the frequency split and modulates both the frequency (FM) and the amplitude (AM) of the oscillations. Unlike other gyroscope modulation techniques which derive rate information from only the FM information and are subject to aliasing for rate signals with bandwidth exceeding the modulation frequency, the innovation uses both the FM and AM information. By exploiting their orthogonality, the image frequencies from the modulation cancel, thus removing the bandwidth limitation.
BANDWIDTH EXTENSION FOR CONTINUOUS MODE REVERSAL GYROSCOPE
A vibratory gyroscope system having a mechanical resonator (proof mass) and drive circuitry for maintaining oscillation in two axes at a small frequency split. Angular rate input is shifted to the frequency split and modulates both the frequency (FM) and the amplitude (AM) of the oscillations. Unlike other gyroscope modulation techniques which derive rate information from only the FM information and are subject to aliasing for rate signals with bandwidth exceeding the modulation frequency, the innovation uses both the FM and AM information. By exploiting their orthogonality, the image frequencies from the modulation cancel, thus removing the bandwidth limitation.
Frequency mismatch detection method for mode matching in gyroscopes
A method for detecting frequency mismatch in microelectromechanical systems (MEMS) gyroscopes is described. Detection of the frequency mismatch between a drive signal and a sense signal may be performed by generating an output signal whose spectrum reflects the physical characteristics of the gyroscope, and using the output signal to determine the frequency f.sub.C of the sense signal. The output signal may be generated by cross-correlating a random or pseudo-random noise signal with a response signal, where the response signal can be obtained by allowing the noise signal to pass through a system designed to have a noise transfer function that mimics the frequency response of the gyroscope. Since the noise signal is random or pseudo-random, cross-correlating the noise signal with the response signal reveals spectral characteristics of the gyroscope. To improve computational efficiency, the cross-correlation can be performed on demodulated versions of the noise signal and the response signal.
SENSOR
According to one embodiment, a sensor includes a movable member, first, and second counter electrodes, first, and second resistances, and a control device. The movable member includes first and second electrodes and is capable of vibrating. The vibration of the movable member includes first and second components. The first component is along a first direction. The second component is along a second direction crossing the first direction. The first counter electrode opposes the first electrode. The second counter electrode opposes the second electrode. The first resistance includes first and first other end portions. The second resistance includes a second end portion and a second other end portion. The first other end portion is electrically connected to the first counter electrode. The second other end portion is electrically connected to the second counter electrode. The control device includes a controller configured to perform at least a first operation.
THREE-AXIS MICROMECHANICAL ROTATION RATE SENSOR SYSTEM INCLUDING LINEARLY AND ROTATORILY DRIVABLE SENSOR UNITS
A micromechanical rotation rate sensor system and a corresponding manufacturing method are described. The micromechanical rotation rate sensor system includes a first rotation rate sensor unit drivable rotatorily about a first axis in an oscillating manner for detecting a first outside rotation rate about a second axis and a second outside rotation rate about a third axis, the first, second and third axes being situated perpendicularly to one another, and a second rotation rate sensor unit linearly drivable by a drive unit along the second axis in an oscillating manner for detecting a third outside rotation rate about the first axis. The second rotation rate sensor unit is connected to the first rotation rate sensor unit via a first coupling unit for driving the first rotation rate sensor unit by the drive unit.
THREE-AXIS MICROMECHANICAL ROTATION RATE SENSOR SYSTEM INCLUDING LINEARLY AND ROTATORILY DRIVABLE SENSOR UNITS
A micromechanical rotation rate sensor system and a corresponding manufacturing method are described. The micromechanical rotation rate sensor system includes a first rotation rate sensor unit drivable rotatorily about a first axis in an oscillating manner for detecting a first outside rotation rate about a second axis and a second outside rotation rate about a third axis, the first, second and third axes being situated perpendicularly to one another, and a second rotation rate sensor unit linearly drivable by a drive unit along the second axis in an oscillating manner for detecting a third outside rotation rate about the first axis. The second rotation rate sensor unit is connected to the first rotation rate sensor unit via a first coupling unit for driving the first rotation rate sensor unit by the drive unit.
Single axis inertial sensor with suppressed parasitic modes
A single axis inertial sensor includes a proof mass spaced apart from a surface of a substrate. The proof mass has first, second, third, and fourth sections. The third section diagonally opposes the first section relative to a center point of the proof mass and the fourth section diagonally opposes the second section relative to the center point. A first mass of the first and third sections is greater than a second mass of the second and fourth sections. A first lever structure is connected to the first and second sections, a second lever structure is connected to the second and third sections, a third lever structure is connected to the third and fourth sections, and a fourth lever structure is connected to the fourth and first sections. The lever structures enable translational motion of the proof mass in response to Z-axis linear acceleration forces imposed on the sensor.
Single axis inertial sensor with suppressed parasitic modes
A single axis inertial sensor includes a proof mass spaced apart from a surface of a substrate. The proof mass has first, second, third, and fourth sections. The third section diagonally opposes the first section relative to a center point of the proof mass and the fourth section diagonally opposes the second section relative to the center point. A first mass of the first and third sections is greater than a second mass of the second and fourth sections. A first lever structure is connected to the first and second sections, a second lever structure is connected to the second and third sections, a third lever structure is connected to the third and fourth sections, and a fourth lever structure is connected to the fourth and first sections. The lever structures enable translational motion of the proof mass in response to Z-axis linear acceleration forces imposed on the sensor.
Physical quantity sensor having a movable body formed with through-holes to reduce a difference between the inside-hole damping and the squeeze film damping
A physical quantity sensor includes a substrate, a movable body that faces the substrate, a fixed portion that is fixed to the substrate, and a support beam that couples the movable body to the fixed portion. The movable body is displaceable with the support beam as a rotation axis, and includes, in a plan view, a first mass that is located on one side of a second direction with respect to the rotation axis, and a second mass that is located on the other side. Each of the first mass and the second mass has a plurality of through-holes which penetrate through the movable body and each of which has a square shape as an opening shape. When damping is indicated by C, and a minimum value of the damping is indicated by Cmin, C1.5Cmin.