CMOS systems and circuits for sub-degree per hour MEMS gyroscopes

The objective of our research is to develop system architectures and CMOS circuits that interface with high-Q silicon microgyroscopes to implement navigation-grade angular rate sensors. The MEMS sensor used in this work is an in-plane bulk-micromachined mode-matched tuning fork gyroscope (M² – TFG ), fabricated on silicon-on-insulator substrate. The use of CMOS transimpedance amplifiers (TIA) as front-ends in high-Q MEMS resonant sensors is explored. A T-network TIA is proposed as the front-end for resonant capacitive detection. The T-TIA provides on-chip transimpedance gains of 25MΩ, has a measured capacitive resolution of 0.02aF /√Hz at 15kHz, a dynamic range of 104dB in a bandwidth of 10Hz and consumes 400μW of power. A second contribution is the development of an automated scheme to adaptively bias the mechanical structure, such that the sensor is operated in the mode-matched condition. Mode-matching leverages the inherently high quality factors of the microgyroscope, resulting in significant improvement in the Brownian noise floor, electronic noise, sensitivity and bias drift of the microsensor. We developed a novel architecture that utilizes the often ignored residual quadrature error in a gyroscope to achieve and maintain perfect mode-matching (i.e.0Hz split between the drive and sense mode frequencies), as well as electronically control the sensor bandwidth. A CMOS implementation is developed that allows mode-matching of the drive and sense frequencies of a gyroscope at a fraction of the time taken by current state of-the-art techniques. Further, this mode-matching technique allows for maintaining a controlled separation between the drive and sense resonant frequencies, providing a means of increasing sensor bandwidth and dynamic range. The mode-matching CMOS IC, implemented in a 0.5μm 2P3M process, and control algorithm have been interfaced with a 60μm thick M2−TFG to implement an angular rate sensor with bias drift as low as 0.1°/hr ℃ the lowest recorded to date for a silicon MEMS gyro.Ph.D.Committee Chair: Farrokh Ayazi; Committee Member: Jennifer Michaels; Committee Member: Levent Degertekin; Committee Member: Paul Hasler; Committee Member: W. Marshall Leac

NASA Tech Briefs, October 2003

Topics covered include: Cryogenic Temperature-Gradient Foam/Substrate Tensile Tester; Flight Test of an Intelligent Flight-Control System; Slat Heater Boxes for Thermal Vacuum Testing; System for Testing Thermal Insulation of Pipes; Electrical-Impedance-Based Ice-Thickness Gauges; Simulation System for Training in Laparoscopic Surgery; Flasher Powered by Photovoltaic Cells and Ultracapacitors; Improved Autoassociative Neural Networks; Toroidal-Core Microinductors Biased by Permanent Magnets; Using Correlated Photons to Suppress Background Noise; Atmospheric-Fade-Tolerant Tracking and Pointing in Wireless Optical Communication; Curved Focal-Plane Arrays Using Back-Illuminated High-Purity Photodetectors; Software for Displaying Data from Planetary Rovers; Software for Refining or Coarsening Computational Grids; Software for Diagnosis of Multiple Coordinated Spacecraft; Software Helps Retrieve Information Relevant to the User; Software for Simulating a Complex Robot; Software for Planning Scientific Activities on Mars; Software for Training in Pre-College Mathematics; Switching and Rectification in Carbon-Nanotube Junctions; Scandia-and-Yttria-Stabilized Zirconia for Thermal Barriers; Environmentally Safer, Less Toxic Fire-Extinguishing Agents; Multiaxial Temperature- and Time-Dependent Failure Model; Cloverleaf Vibratory Microgyroscope with Integrated Post; Single-Vector Calibration of Wind-Tunnel Force Balances; Microgyroscope with Vibrating Post as Rotation Transducer; Continuous Tuning and Calibration of Vibratory Gyroscopes; Compact, Pneumatically Actuated Filter Shuttle; Improved Bearingless Switched-Reluctance Motor; Fluorescent Quantum Dots for Biological Labeling; Growing Three-Dimensional Corneal Tissue in a Bioreactor; Scanning Tunneling Optical Resonance Microscopy; The Micro-Arcsecond Metrology Testbed; Detecting Moving Targets by Use of Soliton Resonances; and Finite-Element Methods for Real-Time Simulation of Surgery

Thermomechanical and mechanical characterization of a 3-axial MEMS gyroscope

Työn tavoitteena oli automaattisten, tehokkaiden ja edullisten testauslaitteistojen ja -menetelmien kehittäminen kolmiakselisten mikroelektromekaanisten (MEMS) gyroskooppien mekaaniseen ja termomekaaniseen karakterisointiin. Työn painotuksena oli testausmenetelmien ja -laitteistojen kehittäminen ja gyroskooppien vaurioanalyysit jäävät tämän työn ulkopuolelle. Gyroskooppi on kulmanopeuden mittaamiseen ja asennon aistimiseen käytettävä anturi. Mekaaninen karakteristointi kattaa gyroskooppien korkean G-arvon iskumaiset kuormitukset ja tärinäkuormitukset. Lämpömekaaninen karakterisointi kattaa gyroskooppien ympäristöolojen kontrolloimista lämpö-, kosteus- tai monikaasu -kaapissa. Tässä työssä kehitettiin menetelmä kolmiakselisten MEMS-gyroskooppien karakterisointiin lämpö- ja kosteuskaapissa. Menetelmä koostuu yksiakselisesta servomoottorista, servo-ohjaimesta ja ohjaussovelluksesta, jonka avulla voidaan samanaikaisesti mitata ja tallentaa gyroskooppien kulmanopeus kaikilta kolmelta (X, Y ja Z) akselilta sekä mitata ympäristön lämpötilaa. Korkean G-arvon iskumaisiin kuormituksiin tarkoitettu laitteisto koostuu pneumaattisesta iskutestauslaitteesta, jossa käytetään mekaanista iskua korkean G-arvon saavuttamiseen. Olemassa olevaa laitteistoa muutettiin siten että sillä voidaan saavuttaa suurempia G-arvoja (aina 80 000G:hen asti) ja mahdollistaa gyroskooppien tutkiminen eri asennoissa. Tärinäkuormituslaittesto koostuu signaaligeneraattorista ja täristinmoottorista, joka soveltuu gyroskooppien tärinätestaukseen. Signaaligeneraattoria käytetään eri taajuisten signaalimuotojen syöttämiseen täristinmoottorille, joka tärisee annetun syötteen mukaisesti. Pyörityslaitteen toiminnallisuutta testattiin yhdellä gyroskoopilla huoneenlämmössä. Gyroskoopin X, Y ja Z-akselien kulmanopeuksien keskiarvot sekä -hajonta mitattiin. Korkean g-arvon iskutestauslaitteistoa testattiin kuudella mittauksella, jossa gyroskoopit rikkoutuivat ensimmäisellä iskulla. Tärinätestauslaitteistoa testattiin yhdellä gyroskooppi-piirilevyllä. Gyroskooppi-piirilevyn päälle asetettiin kiihtyvyysanturi, jolla mitattiin tärinästä aiheutuvan kiihtyvyyden RMS-arvo, huippuarvo ja kokonaisenergia. Tulevat jatkotutkimukset keskittyvät pyöritys-, isku- ja tärinälaitteistoilla testattujen MEMS-gyroskooppien vaurioanalyysiin.The purpose of this thesis was to develop automated, efficient and economical methods for the mechanical and thermomechanical characterization of a digital 3-axial microelectromechanical systems (MEMS) gyroscope. The development of the test equipment and methods was the emphasis of this thesis, but the failure analyses of MEMS gyroscopes are beyond the scope of this work. A gyroscope is a device for measuring angular velocity and sensing change in orientation around its X, Y and Z-axis. The experimental part is divided into two sections, of which the first one is focused on high-G shock impact and vibration loading and the second on thermomechanical characterization. A rotation device was developed for the characterization of the MEMS gyroscopes in a temperature and humidity chamber. The rotation device consists of a oneaxial servo-motor, a servo-drive and a control program for the readout of angular velocity. The device is capable of simultaneously recording the angular velocities of the gyroscopes from all three axes while rotating the gyroscopes around a single axis. The device also records the temperature of the environment. The high-G shock impact equipment consists of a pneumatically assisted shock tester that relies on mechanical impact to generate the high-G shock pulse. An existing mechanical shock impact system was modified to gain higher G-values (up to 80 000G) and to enable the inspection of gyroscopes in different orientations. The vibration test equipment consists of a waveform generator and a vibration shaker, for the vibration testing of gyroscopes. The waveform generator is capable of outputting different waveforms with different frequencies to the shaker that vibrates with the given output. The functionality of the rotation device was tested with rotating one gyroscope board at room temperature. Respective averages and standard deviations of angular velocities were measured in the direction of X, Y and Z axes. The functionality of the high-G shock impact test equipment was verified with six measurements where all of the gyroscopes failed on first impact. The vibration test equipment was tested with one gyroscope board. Root mean square (RMS), peak value and total energy of acceleration were measured with an accelerometer placed on top of the vibrating gyroscope board

NASA Tech Briefs, November 1993

Topics covered: Advanced Manufacturing; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Workshop Proceedings: Sensor Systems for Space Astrophysics in the 21st Century, Volume 2

In 1989, the Astrophysics Division of the Office of Space Science and Applications initiated the planning of a technology development program, Astrotech 21, to develop the technological base for the Astrophysics missions developed in the period 1995 to 2015. The Sensor Systems for Space Astrophysics in the 21st Century Workshop was one of three Integrated Technology Planning workshops. Its objectives were to develop an understanding of the future comprehensive development program to achieve the required capabilities. Program plans and recommendations were prepared in four areas: x ray and gamma ray sensors, ultraviolet and visible sensors, direct infrared sensors, and heterodyne submillimeter wave sensors

NASA SBIR abstracts of 1992, phase 1 projects

The objectives of 346 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1992 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 346, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1992 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included