Robotics Fundamentals Series: Gyroscopes
PrintGyroscopes are heading sensors which are based on a rotating mechanism, whose position relative to its mounting is continually measured. Based on this, the motion and position of the device can be determined. Gyroscopes can be classified in two categories, mechanical gyroscopes and optical gyroscopes.
Mechanical Gyroscopes
Mechanical gyroscopes exhibit an interesting behavior which is referred to as precession. If you have a spinning gyroscope and you try to rotate its spin axis, the gyroscope will instead try to rotate about an axis at right angles to your force axis. A rate-gyroscope is an example of a mechanical gyroscope that measures angular speeds instead of absolute orientation.
Figure 1. Mechanical gyroscopes spin about their spin axis
Optical Gyroscopes
Unlike mechanical gyroscopes, optical gyroscopes have virtually no moving parts. Optical gyroscopes are angular speed sensors that use two monochromatic light beams, or lasers, emitted from the same source. The underlying principal is that the speed of light remains unchanged; therefore geometric change can cause light to take a varying amount of time to reach its destination. Optical gyroscopes are designed using the Sagnac effect, which creates interference patterns due to frequency shift of light.
A senior design team at Rensselaer Polytechnic Institute (RPI) set out to develop an interdisciplinary mechatronic system by designing and prototyping a two-wheeled robotic locomotion platform in LabVIEW. This robotic platform combines measurements from an inclinometer and a rate-gyroscope to calculate the angular position relative to gravity, in order to maintain system stability while providing precise maneuverability.
Figure 2. A two wheeled balancing transport platform uses a gyroscope to help maintain system stability
See also:
Two Wheel Balancing Transport Platform
To learn more about robotics, refer to the Robotics Fundamentals Series homepage at ni.com/zone.
Resources
How Gyroscopes Work from HowStuffWorks
Gyroscope from Wikipedia, the free eynclopedia
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