Vibration robust x-axis ring gyro transducer
View Patent ↗A micro-electromechanical systems (MEMS) transducer ( 100, 700 ) is adapted to use lateral axis vibration to generate non-planar oscillations in a pair of teeter-totter sense mass structures ( 120/140, 720/730 ) in response to rotational movement of the transducer about the rotation axis ( 170, 770 ) with sense electrodes connected to add pickups (e.g., 102/107, 802/807 ) diagonally from the pair of sense mass structures to cancel out signals associated with rotation vibration.
1. A method of sensing angular rotation of a lateral axis sensor about a rotational sense axis, comprising:
imparting synchronous in-plane oscillatory motion to first and second symmetric mass transducers symmetrically connected side-by-side along the rotational sense axis by a shared drive mechanism which is directly connected in common to the first and second symmetric mass transducers to induce counter rotational motion in the first and second symmetric mass transducers and which oscillates in a linear direction that is perpendicular to the rotational sense axis so that the first and second symmetric mass transducers oscillate in opposition to one another;
measuring a rate of angular rotation of the lateral axis sensor about the rotational sense axis using first and second electrode pairs positioned under the first and second symmetric mass transducers and symmetrically positioned in relation to a rotational sense axis, where the first and second symmetric mass transducers are adapted for counter rotational motion relative to the rotational sense axis in response to angular rotation of the sensor around the rotational sense axis, and are adapted for co-rotational motion relative to the rotational sense axis in response to an angular acceleration force around the rotational sense axis, so that the angular acceleration force measured at the first and second symmetric mass transducers is cancelled or suppressed.
2. The method of claim 1 , where measuring the rate of angular rotation comprises combining a first pickup signal from a first electrode in the first electrode pair with a second pickup signal from a second electrode in the second electrode pair, where the first and second electrodes are positioned on opposite sides of the rotational sense axis, such that rotational vibration around the rotational sense axis is cancelled out.
3. The method of claim 1 , where measuring the rate of angular rotation comprises adding first and second capacitive signals associated with angular acceleration of the lateral axis sensor around the rotational sense axis substantially cancel one another, where the first capacitive signal is captured at a first electrode positioned under the first symmetric mass transducer on one side of the rotational sense axis, and where the second capacitive signal is captured at a second electrode positioned under the second symmetric mass transducer on the other side of the rotational sense axis.
4. The method of claim 1 , where imparting synchronous in-plane oscillatory motion comprises imparting linear in-plane oscillating motion to the shared drive mechanism connected between the first and second symmetric mass transducers.
5. The method of claim 1 , where imparting synchronous in-plane oscillatory motion comprises driving a pair of ring-shaped sense mass structures into rotational in-plane synchronous anti-phase oscillating motion.
6. A method of sensing angular rotation of a lateral axis sensor about a rotational sense axis, comprising:
imparting oscillating in-plane linear motion to a shared drive mechanism that is directly connected between first and second symmetric mass transducers to drive the first and second symmetric mass transducers into counter rotational oscillatory motion about respective rotation axes which are perpendicular to the rotation sense axis;
measuring a rate of angular rotation of the lateral axis sensor about the rotational sense axis using first and second electrode pairs positioned under the first and second symmetric mass transducers and symmetrically positioned in relation to a rotational sense axis, where the first and second symmetric mass transducers are adapted for counter rotational motion relative to the rotational sense axis in response to angular rotation of the sensor around the rotational sense axis, and are adapted for co-rotational motion relative to the rotational sense axis in response to an angular acceleration force around the rotational sense axis, so that the angular acceleration force measured at the first and second symmetric mass transducers is cancelled or suppressed.
7. A method of sensing angular rotation of a lateral axis sensor about a rotational sense axis, comprising:
imparting synchronous counter rotational in-plane oscillatory motion to first and second symmetric mass transducers symmetrically connected side-by-side along the rotational sense axis by driving a shared drive mechanism to oscillate in a linear direction that is perpendicular to the rotational sense axis, where the shared drive mechanism connects the first and second symmetric mass transducers to impart synchronous counter rotational in-plane oscillatory motion to the first and second symmetric mass transducers and to resist anti-phase linear movement of the first and second symmetric mass transducers;
measuring a rate of angular rotation of the lateral axis sensor about the rotational sense axis using first and second electrode pairs positioned under the first and second symmetric mass transducers and symmetrically positioned in relation to a rotational sense axis, where the first and second symmetric mass transducers are adapted for counter rotational motion relative to the rotational sense axis in response to angular rotation of the sensor around the rotational sense axis, and are adapted for co-rotational motion relative to the rotational sense axis in response to an angular acceleration force around the rotational sense axis, so that the angular acceleration force measured at the first and second symmetric mass transducers is cancelled or suppressed.