What is gyroscope?

It measures and maintains angular velocity and orientation. It frequently functions in a variety of applications as a navigational aid, stabilising device, and attitude controller. The words gyro, which means to turn, and skopein, which means to look, are derived from the Greek.

Gyro design:

A gyroscope can be visualised as a large rotor supported by hinge-like support rings. By virtue of the rolling bearings included in the universal joints, the central rotor is shielded from external torques. The axis of the spinning wheel determines the direction of rotation.

The rotor maintains a high-speed fulcrum on the centre rotor, giving it extraordinary high-speed stability. Three rotational degrees of freedom exist for the rotor.

Working principle:

A gyroscope's operation is governed by gravity. This is explained as the product of the angular momentum experienced by the torque on the disk causing gyroscopic precession in the spinning wheel. This process is called gyroscopic motion or gyroscopic force and is defined as the tendency of a rotating object to maintain its orientation. We know that a rotating object has angular momentum that must be conserved. This is because any change in the axis of rotation will change orientation, which will change angular momentum. Therefore, we can say that the working principle is based on the conservation of angular momentum.

Key parts:

It is usually made up of several key parts that work together to make it functional. These are the main parts:

Rotor: The rotor is the central part. This is a spinning wheel or disc with angular momentum. The rotation of the rotor provides stability and resistance to orientation changes.

Hooks: The rotor is mounted on a set of hooks, which are hinged supports that allow the rotor to rotate freely in three dimensions. The hooks support the rotor's axis of rotation and provide stability, allowing it to respond to changes in orientation.

Bearings: Bearings are used to support the rotor and reduce friction, allowing it to rotate smoothly and maintain angular momentum. They allow free rotation of the rotor without resistance to frictional forces.

Chassis/Enclosure: The gyro's chassis or enclosure contains and protects the internal components. It ensures the structural integrity and stability of the entire gyro system.

Drive mechanism: Some gyroscopes have a drive mechanism that provides the initial rotation or spins the rotor. This mechanism can be an electric motor or any other device that gives the rotor a rotational movement.

Sensors: Gyroscopes often contain sensors such as accelerometers or optical detectors to measure the gyroscope's angular velocity or attitude changes. These sensors provide feedback on the movement of the gyroscope that can be used for control or measurement purposes.

Output interface: Gyros can have an output interface or connectors that allow the gyroscope to communicate with external devices or systems. This interface can be analog or digital, depending on specific application requirements.

Types of gyroscopes:

1)Mechanical gyroscope
2)Optical gyroscope
3)Gas gyroscope

Mechanical:

The working principle of a mechanical type is based on the conservation of angular momentum. It is also one of the most famous gyroscopes. A mechanical gyroscope relies on the rotation of a ball bearing. These have been replaced by modern forms of gyroscopes because they are noisier. They are used in the navigation of large aircraft and in the guidance of missiles.

Optical:

These  rely on a ball bearing or spinning wheel. Nor are they based on the law of conservation of angular momentum. Optical  uses two coils of optical fibers that rotate in different directions. Because there is no movement in optical gyroscopes, they are considered durable and can be used in modern spacecraft and rockets.

Gas gyroscopes:

With a gas gyroscope, the friction between moving parts is reduced by suspending the rotor with compressed gas. In order to create the Hubble telescope, NASA used a gaseous gyroscope. Compared with other gyroscopes, the gas bearing is quieter and more accurate.

Other types:

Fiber Optic Gyroscope (FOG): FOG uses the principle of the Sagnac effect. In FOG, a spool of optical fiber is wound on a spool and the laser beam is split and directed clockwise and counterclockwise along the fiber loop. As the system rotates, the Sagnac effect causes a phase difference between the two spokes that can be measured to determine rotational speed. FOGs provide high accuracy, precision and reliability and are commonly used in navigation systems and aerospace applications.

Ring Laser (RLG): RLGs work on the same principle as FOGs, using the Sagnac effect. They consist of a laser beam circulating in a closed ring formed by mirrors with two opposing beams. The rotation of the gyroscope causes a shift in the frequency of the laser beams, which can be detected and used to determine rotational speed. RLGs are known for their high sensitivity and are used in navigation systems, aerospace applications and research.

Hemispheric Resonator (HRG): HRGs use the concept of vibrational resonances to measure rotation. They consist of a small vibrating resonator placed in a hollow hemispherical shell. As the gyroscope rotates, the Coriolis effect causes a change in the motion of the resonator, which can be observed and used to determine rotational speed. HRGs are compact, have a high degree of accuracy and are used in navigation systems and the aerospace industry.

Microelectromechanical systems (MEMS) gyroscope: MEMS are miniature solid-state devices that use microfabrication techniques to create tiny mechanical structures. They usually consist of a vibrating mass or set of vibrating beams whose motion changes through rotation. MEMS gyroscopes are commonly used in consumer electronics such as smartphones, game controllers, and motion sensing devices.

Uses:

The effect of all this is that as you spin the gyroscope, the axis tends to keep pointing in the same direction. If you mount the gyro on the gimbal so it can keep pointing in the same direction, it will. This is the base of the gyro.

If you mount two gyroscopes with their axes perpendicular to each other on a platform and place the platform within a set of gimbals, the platform remains completely rigid because the gimbals can rotate as desired. This is the basis of inertial navigation systems (INS).

In INS, sensors on the gimbals detect when the platform is rotating. INS uses these signals to find out how the vehicle is turning relative to the platform. If you add a set of three sensitive accelerometers to the platform, you can see exactly where the vehicle is going and how its movement changes in all three directions. With this information, the aircraft's autopilot can keep the aircraft on course and the missile guidance system can guide the missile into the desired trajectory!

What is the difference between an accelerometer and a gyroscope?

An accelerometer is a device used for both acceleration measurement and vibration detection.  Another way to define an accelerometer is as an electromechanical device that measures the forces caused by acceleration.