Mohammad Zaman

US Patent:

7043985, May 16, 2006

Filed:

Jan 12, 2005

Appl. No.:

11/034145

Inventors:

Farrokh Ayazi - Atlanta GA, US
Mohammad Faisal Zaman - Atlanta GA, US

Assignee:

Georgia Tech Research Corporation - Atlanta GA

International Classification:

G01P 9/04

US Classification:

7350404, 7350412, 7350414, 295921

Abstract:

A microstructure comprising an in-plane solid-mass electrically conductive tuning fork gyroscope and fabrication methods. The gyroscope is formed using substrate material having lower and upper layers sandwiching a sacrificial insulating layer. An exemplary gyroscope comprises a low-resistivity single-crystal silicon substrate having a lower support layer and an upper flexible support layer. Two opposed proof masses that are separated from the lower support layer lie in and are supported by the upper flexible support layer. Two drive electrodes are disposed adjacent to the proof masses and are insulatably supported by the lower support layer and are separated from the upper flexible support layer. Sense, balance and tuning electrodes are disposed adjacent to the proof masses and are insulatably supported by the lower support layer and are separated from the upper flexible support layer. The operational mode shapes are in-plane with the substrate surface and only measures angular motion that are orthogonal to the plane of the substrate.

US Patent:

8061201, Nov 22, 2011

Filed:

Jul 11, 2008

Appl. No.:

12/218087

Inventors:

Farrokh Ayazi - Atlanta GA, US
Ajit Sharma - Richardson TX, US
Mohammad Faisal Zaman - Atlanta GA, US

Assignee:

Georgia Tech Research Corporation - Atlanta GA

International Classification:

G01P 9/04

US Classification:

7350412, 7350414

Abstract:

Disclosed are methods and a sensor architecture that utilizes the residual quadrature error in a gyroscope to achieve and maintain perfect mode-matching, i. e. , 0 Hz split between the drive and sense mode frequencies, and to electronically control sensor bandwidth. In a reduced-to-practice embodiment, a 6 mW, 3V CMOS ASIC and control algorithm are interfaced to a mode-matched MEMS tuning fork gyroscope to implement an angular rate sensor with bias drift as low as 0. 15/hr and angle random walk of 0. 003/√hr, which is the lowest recorded to date for a silicon MEMS gyroscope. The system bandwidth can be configured between 0. 1 Hz and 1 kHz.

US Patent:

7360423, Apr 22, 2008

Filed:

Jan 27, 2006

Appl. No.:

11/341721

Inventors:

Farrokh Ayazi - Atlanta GA, US
Mohammad Faisal Zaman - Atlanta GA, US
Ajit Sharma - Bangalore, IN
Babak Vakili Amini - Marietta GA, US

Assignee:

Georgia Tech Research Corp. - Atlanta GA

International Classification:

G01P 9/04

US Classification:

7350412, 7350413

Abstract:

Disclosed are resonant vibratory gyroscopes and fabrication methods relating thereto. The angular motion sensor comprises a resonating star gyroscope which comprises a vibratory solid or shell-type structure for rate sensing or measuring angle of rotation. The structure formed as a merged superposition of two square entities, yields in-plane degenerate flexural modes that are used to sense rotation around the axis perpendicular to the substrate. The resonating star gyroscope may be implemented using the primary flexural degenerate modes. Such an implementation has been successfully demonstrated by the authors using trench-refilled polysilicon and epitaxial polysilicon as the structural material. It is also possible to use a solid star-shaped resonator (with or without perforations) for the gyroscope. The authors also suggest the operation of the resonating star gyroscope employing the higher-order flexural modes.

US Patent:

20120192647, Aug 2, 2012

Filed:

May 19, 2011

Appl. No.:

13/111501

Inventors:

Farrokh Ayazi - Atlanta GA, US
Ajit Sharma - Richardson TX, US
Mohammad Faisal Zaman - Atlanta GA, US

International Classification:

G01C 19/56

US Classification:

7350412

Abstract:

Disclosed are methods and a sensor architecture that utilizes the residual quadrature error in a gyroscope to achieve and maintain perfect mode-matching, i.e., 0 Hz split between the drive and sense mode frequencies, and to electronically control sensor bandwidth. In a reduced-to-practice embodiment, a 6 mW, 3V CMOS ASIC and control algorithm are interfaced to a mode-matched MEMS tuning fork gyroscope to implement an angular rate sensor with bias drift as low as 0.15/hr and angle random walk of 0.003/√hr, which is the lowest recorded to date for a silicon MEMS gyroscope. The system bandwidth can be configured between 0.1 Hz and 1 kHz.

US Patent:

20120227487, Sep 13, 2012

Filed:

Aug 31, 2010

Appl. No.:

13/393291

Inventors:

Farrokh Ayazi - Atlanta GA, US
Mohammad Faisal Zaman - Worcester MA, US

International Classification:

G01P 15/14
H05K 3/10

US Classification:

7350408, 216 6

Abstract:

A Coriolis-based bulk acoustic wave gyroscope includes a center-supported resonating element with capacitively-coupled drive, sense, and control electrodes. The resonating element has a first substantially solid or perforated region which is connected to the center-support by a second region characterized by a plurality of spokes or beams. When operating in a resonance state, the first region undergoes a bulk acoustic mode of vibration while the second region undergoes a flexural mode of vibration. Energy losses associated with the flexural mode of vibration reduce the overall quality factor (Q) at high resonance frequencies creating a large bandwidth and a fast response time without needing vacuum.

US Patent:

20130283911, Oct 31, 2013

Filed:

Dec 5, 2011

Appl. No.:

13/991672

Inventors:

Farrokh Ayazi - Atlanta GA, US
Mohammad Zaman - Worcester MA, US

International Classification:

G01C 19/56
G01C 25/00

US Classification:

7350412, 29825

Abstract:

A single proof-mass, dual-axis gyroscope apparatus comprises a resonating body member and first and second electrodes each capacitively coupled to the resonating body member by a respective lateral capacitive air gap and a vertical capacitive air gap. The width of one of the lateral capacitive air gap of the first electrode is substantially smaller than the vertical capacitive air gap. The width of one of the vertical capacitive air gap of the second electrode is substantially smaller than the lateral capacitive air gap. The apparatus claimed can address the process variation such as vertical and lateral dimension variation by electrostatic tuning method.