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
Prepared by:
1) PATEL HEMINKUMAR
2) PATEL HARSHAL
3) ATALIYA JAYDEEP
4) BHOJANI RADHIK

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
o Initial 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 18th and 19th 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 20th 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 superconductor generates a magnetic 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't rely 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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