Gyroscopes

Device used to measure or maintain orientation

Works on the principals of angular momentum
Initial axis of rotation is conserved

Consists of a spinning mass on an axel

1. Gyroscope
SIGMA INSTITUTE OF TECHNOLOGY AND ENGINEERING
COMPUTER ENGG. (B.E)(SEM –1)
SUB : PHYSICS
Preparedby:
1)PATELHEMINKUMAR
2)PATELHARSHAL
3)ATALIYAJAYDEEP
4)BHOJANIRADHIK

2. Outline
Introduction to Gyroscopes
•Theory of operation
•Applications
Historic and Modern Varieties
•History of gyroscopes
•Current technology
Implementation
•Algorithms
•Feedback and control
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3. •Device used to measure or maintain orientation
•Works on the principals of angular momentum
oInitial axis of rotation is conserved
•Consists of a spinning mass on an axel
What is a Gyroscope ?
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4. •Mechanical Gyroscope
•Spinning mass mounted on gimbals
•Free-output vs. Fixed-output
•Sensors on axis to detect rotation
•Procession
•Electronic Gyroscope
•Coriolis vibratory gyroscope
•Proof mass fed oscillating current to induce vibrations
•Vibrating mass tends to oscillate in initial plane of reference
•When rotated, oscillations in orthogonal plane detected by circuitry
How Gyroscopes Work
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5. Gyrocompass
•Used by ships to find true north
•Seeks minimum potential energy
Stability Assistance
•Hubble Space Telescope
•Bicycles
Inertial Guidance System
•Guided Missiles
•Measure angular velocity in inertial reference frame
•Detect changes to orientation
•Combined with accelerometer for 6 axis sensor
Common Uses
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6. •Wii Remote
•Tilt, yaw, pitch
•Rate of angular movement
•Smart Phones
•Screen Orientation
•Gaming Input
•Laptops
•Free fall detection
Consumer Electronics
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7. History of Gyroscopes
Initially a toy, not a tool
•Tops were common in ancient civilizations
•Began to be used in naval navigation and science during the 18
th
and 19
th
centuries
1852 French gyroscope used
to measure Earth’s rotation
1860 gyro used to model orbital motion
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8. History of Gyroscopes
•Integration with electronics
•In the early 20
th
century, gyroscopes became combine with electric motors, allowing them to
operate without mechanical power
•Miniaturized during WWII for torpedo, ship, and plane navigation
•Further miniaturized with the advent for silicon-based electronics
WWII are bomb release control mechanism
Common $50 consumer gyroscope available on Sparkfun
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9. Types of Gyroscopes
Rotary gyroscope
Rotor suspended in a gambol spins independently in order to conserve angular momentum
Mostly unused in modern systems
Fiber optic gyroscope (FOG)
Fiber optic coil determines changes in orientation by path of light in the coil
Beam traveling against rotation has slightly shorter path
Microelectromechanical systems(MEMS)
Uses very small vibrating mechanism to detect changes
London moment
Spinning superconductorgenerates amagnetic field
Extremely accurate tool or modern science
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10. Common Gyroscope Criteria
Performance
Measurement range
Number of sensing axes
Nonlinearity
Bandwidth
Angular Random Walk (ARW)
Bias
Bias Drift
Bias Instability
Specifications
Cost
Working temperature range
Shock survivability
Size/Mass
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11. Angular Random Walk

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12. Examination of Recent Gyros
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13. •Noise reduction via low pass filter
•Scale calibration to get meaning from gyroscope data
•Integrate data over time to get “absolute angle”
•Enhancement using Kalman filter
Can reduce/eliminate integration drift
General Algorithms
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14. Inertial Navigation Systems
Dead reckoning –using previous position to determine current position
Used on ships, aircraft, submarines, missiles, spacecraft, etc
Firefighters/military –step based INS
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15. Low refresh rate
–10Hz? 20Hz?
Relatively low resolution
–Location to n meters
Limited to outdoors
High refresh rate
–Kilohertz
Relatively high resolution
–But prone to drift
Doesn'trely on satellites
GPS INS
Combine both sensors using Kalman Filter to
produce highly accurate results
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16. SIGMA INSTITUTE OF TECHNOLOGY AND ENGINEERING (PAGE NO. 16)

17. Feedback Control Systems
oVibration detected using gyroscopes
oMovements modeled as sinusoid
oLens is shifted to counteract vibration
Optical Image Stabilization
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18. SIGMA INSTITUTE OF TECHNOLOGY AND ENGINEERING (PAGE NO. 18)

19. •http://physics.kenyon.edu/EarlyApparatus/Mechanics/Gyroscope/Gyrosco
pe.html
•http://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=327
•http://orgs.usd.edu/nmm/News/Newsletter/August2010/ConnResearch.ht
ml
•http://www.sensorwiki.org/doku.php/sensors/gyroscope
Reference
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20. Thank you
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