ECE5320 Mechatronics Literature Survey on Sensors and Actuators Topic: Gyroscopes

1. ECE5320 MechatronicsLiterature Survey on Sensors and Actuators Topic: Gyroscopes Prepared by: Daniel Ricsi Dept. of Electrical and Computer Engineering Utah State University E:daniel.ric@aggiemail.com 2/26/2009

2. Outline • Reference list • To explore further • Major applications • Gyro principal • Gyroscopes • Types of gyros • Gyro performance • Gyro parameters • Specifications of CRS03-02 • MicroStrain 3DM-GX1 • Benchmarking: Fiber-optic gyro • Mayor applications • Final Remarks ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • http://web.mac.com/ryo_watanabe/iWeb/Ryo%27s%20Holiday/Gyro%20Sensor.html • http://www.motusbioengineering.com/sensor-comparisons-technical-note.htm • http://metrology.hut.fi/courses/S-108.4010/2007/Spring_2007_MEMS_JKa.pdf • http://automation.tkk.fi/attach/AS-84-3145/Gyros.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To Explore Further • http://www.microstrain.com/3dmgx1.aspx • http://www.microstrain.com/inertia-link.aspx • http://www.xbow.com/Inertial_home.aspx • http://www.vti.fi/en/ • http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=4245717 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Gyro principal • Gyro is a type of inertial sensor • Based on conservation of momentum. • Gyro measures rotation • Measure angular velocity • Radians/sec • Integrating the velocity is possible obtain the angular position http://en.wikipedia.org/wiki/File:Gyroscope_operation.gif ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Gyroscopes • Non-sensitive to magnetic disturbances. It can be used in environment where the magnetic field is not available • Mechanical gyroscopes • Based on conservation of momentum • Measure the changes in linear- or angular momentum • Optical gyroscopes • No moving parts (gravitation doesn’t affect) ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Mechanical Gyroscopes • Based on conservation of momentum • Continuous angular movement • Mm. flywheel gyroscope • Oscillatory angular momentum • Employ a torsionally suspended mass oscillating back and forth at its natural frequency • Continuous linear momentum • Steady stream of fluid, plasma or electrons, which tend to maintain its established velocity • Oscillatory linear momentum • a set of discrete masses moving back and forth along a straight-line path ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Mechanical Flywheel Gyroscope • A rapidly spinning wheel or sphere with big inertia causes a gyroscopic precision, when turned • Rotor is rotated with electrical motor • Rotor on supported by low-friction bearings and in a gimbal • Both axis of the gimbal are perpendicular to the rotating axis ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Optical Gyroscopes • Most promising sensors in the mobile robotics in near future. • Two laser beams are rotating opposite directions in a closed loop • When the beams are combined the rotation rate and direction can be calculated from the interference fringes • Five basic principles: • Active optical resonator • Passive optical resonator • Open loop fibre optic interferometer (anal.) • Closed loop fibre optic interferometer (digit.) • Fibre optic resonator ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Active Ring-laser Gyro • Active optical resonator • Resonator is a laser itself • (active) • If gyro is rotated counter clock wise direction, the counter-clock wise beam is travelling slightly longer than the opposite beam • The change in the path length is proportional to the rotation rate • In very small rotation rates • there is a dead-band because of frequency lock-in http://automation.tkk.fi/attach/AS-84-3145/Gyros.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. Gyroscopes • There are two basic classes of rotation sensing gyros: • Rate gyros • The output is relative to the angular speed • Rate integrating gyros • Indicate the actual turn angle or heading • The angle is relative (must have a initially referenced to a known orientation. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Types of Gyroscopes • Based on coriolis force • Vibrating wheel • Two axis, excitation around axis of symmetry • Vibrating bar gyro • Tuning fork gyro • Analog Devices • Signal conditioning http://metrology.hut.fi/courses/S-108.4010/2007/Spring_2007_MEMS_JKa.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Gyro Performance • Classification according to bias drift • Rate grade 10 – 10000 deg/h • Tactical grade 0,01 – 10 deg/h • Navigation grade <0,01 deg/h • Mechanical, optical (fog, laser ring), MEMS (tuning fork, vibrating ring) • Dynamic area: few Hz – 500Hz ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Gyro Parameters • These parameters are not easy to calibrate • Drift (see previous slide) [deg/h] • Max angular speed [deg/s] • Dynamic resolution [Hz] http://blogs.smh.com.au/radar/robot.jpg ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. CRS03-02 • This is a small gyro • Output : Analog DC voltage centered at about 2.5VDC • Rate Range : +/-100 deg/sec • Scale Factor : 20mV/(deg/sec) • Bias (neutral) : 50% of Vdd • Number of Axis : 1 • Bandwidth(-3dB, -90deg) : 10 Hz • Dimensions : 29 x 18 x 29 mm • Power supply (Vdd) : 5VDC +/-250mV • Current dissipation :  less than 50mA(150mA for initialization http://www.davidson.com.au/products/ inertialsystems/image/crs03.jpg CRS03-02 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. MicroStrain 3DM-GX1 • Three angular rate gyros • Three orthogonal DC accelerometers • Three orthogonal magnetometers • Multiplexer, 16 bit A/D converter, and embedded microcontroller • Output its orientation in dynamic and static environments • Update rates of 350 Hz • http://www.microstrain.com/3dmgx1.aspx ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. Benchmarking: Fiber-optic gyro • Optical phase tracking • Extremely high performance • Drift < 0.010/hr http://metrology.hut.fi/courses/S-108.4010/2007/Spring_2007_MEMS_JKa.pdf ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Major Applications • Automotive Yaw Rate Sensor   • Global Positioning System (GPS) Dead-reckoning   • Fluxgate Compass compensation   • In-Car Navigation Systems   • Mobile dish antenna stabilized platform   • Mobile camera platform stabilization   • Robotics   • Simulators   • Telematics / Fleet-management   http://co2calculator.files.wordpress.com/2008/10/segway.jpg http://www.blogcdn.com/www.engadget.com/ media/2008/06/amp_robot_white_back.jpg http://www.geology.smu.edu/~dpa-www/robo/nbot/nbot2/nb12.jpg ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

19. Cont. Applications • Remote Control Vehicles   • Dynamic measurement units   • Drive safety recorder (blackbox for car/marine)   • AGV, wheelchair   • Marine Satellite Compasses   • Angle Wrench   • Agricultural Tractors   • Physiotherapy / therapeutic Equipment   • 3-D input devices   http://www.fas.org/man/dod-101/sys/ac/v-22-pic01461.jpg http://1.bp.blogspot.com/_0x-_F8jtyJQ/ReDTlwO_2oI/AAAAAAAAALA/ZpVgYtZF8Vk/s320/carver.jpg ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

20. Final Remarks • All mechanical Gyros (mems also) can be affected by external noise like vibrations and magnetic field • The best bandwidth up to 400Hz is available with optical gyros (ring laser) with mechanical ones typically < 10-20Hz • MEMS and FOGs are the most used in robotics. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators