MEMS Gyroscope basics | MEMS Gyroscope working operation
This page covers MEMS Gyroscope basics and mentions MEMS gyroscope working operation. It mentions technical specifications and applications of gyroscope and mentions types of gyroscope.
Definition: The device which is used for navigation and angular velocity measurement is known as Gyroscope. The Gyroscope made using MEMS technology is known as MEMS gyroscope. The MEMS gyroscope uses very small vibrating mechanism to detect changes in orientation.
The gyroscopes can measure rotational velocity of one, two or three direction axis.
3-axis accelerometer is used to implement 3-axis gyroscope.
The sensors are used for gyroscope implementation. The figure-1 below depicts simple gyroscope.
Following are the technical specifications of the gyroscope which are essential to
determine its performance. Based on this right gyroscope device is choosen
as per applications of use.
• Size and Mass
• Cost
• Operating temperature range
• Shock survivability
• Range of measurement
• No. of sensing axes
• Nonlinearity
• Bandwidth
• ARW (Angular Random Walk)
• Bias, Bias Drift and Bias Instability
MEMS Gyroscope working operation
What is Gyroscope?:
The device used to measure or maintain orientation is known as
Gyroscope. As mentioned it works on the principals of angular
momentum in which initial axis of rotation is conserved.
It consists of spinning mass on an axel. Following
section mentions how common mechanical and electronic gyroscopes work.
Mechanical Gyroscope: It uses spinning mass mounted on gimbals and sensors on axis to detect rotation.
Electronic Gyroscope: Called coriolis vibratory gyroscope. It uses proof mass fed oscillating current to induce vibrations. The vibrating mass tends to oscillate in initial plane of reference. When rotated, oscillations in orthogonal plane are being detected by the circuitry.
Types of Gyroscopes
Following are the most common 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:
-Fiber optic coil determines changes in orientation by path of light in the coil
-Beam traveling against rotation has slightly shorter path
The other types of gyroscope include Draper Tuning Fork Gyroscope, Piezoelectric Plate Gyroscope, Laser Ring Gyroscope, Micro Laser Gyroscope etc.
Applications of Gyroscope
Following are the applications of gyroscope.
• Used in gyrocompass located in the ships to find the
true north direction.
• Used in bicycles and hubble space
telescopes to provide stability assistance.
• Used in inertial guidance system for guided missiles, to measure angular velocity in
inertial reference frame, to detect changes in orientation etc.
• Used in consumer electronics for different reasons e.g. for free fall detection in laptop,
for screen orientation in smart phones etc.
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