Gyroscopic Stabilization

 

Introduction of Gyroscope

 

(A) Axis Of Spin

If a body is revolving about an axis, the latter is known as axis of spin.

 

(B) Precession

Precession means the rotation about the third axis which is perpendicular to both the axis of spin and axis of couple

(C) Axis Of Precession

The third axis is perpendicular to both the axis of spin and that of couple is known as axis of precessions.

(D) Gyroscope

It is a body while spinning about an axis is free to rotate in other directions under the action of external forces. Examples;; Locomotive, automobile and aero plane making a turn. In certain cases the gyroscopic forces are under sirable whereas in other cases the gyroscopic effect may be utilized in developing desirable.

(E) Gyroscopic Effect

To a body revolving (or spinning) about an axis of spin, if a couple represented by a vector OY perpendicular to axis of spin, then the body tries to process about third axis which is perpendicular both axis of spin &couple. Thus the plane of spin, plane of precession and plane of gyroscopic couple are mutually perpendicular. The above combined effect is known as gyroscopic effect.

 

The expression for the gyroscopic couple is given as:

C = I.⍵.⍵p

Where , C is the gyroscopic couple

I is the moment of inertia

⍵ is the angular velocity

⍵p is the angular velocity of precession

 

History of gyroscopic stabilizers

The first experimental gyroscopes were developed in the late 1860s and early 20th century with less than desirable results. Several large ships used the technology, including the USS Henderson, a troop transport ship, in 1917, which had two 25-ton units, and an Italian cruise liner used three large units in 1930. The cost and weight of the systems became prohibitive, and other forms of stabilization became more readily available. External fin stabilization, which used the speed of the vessel to create stabilization against capsize, became more popular, but by no means more practical - especially with sport anglers.

 

What is Gyroscopic Stabilization?

A gyroscopic stabilizer is a control system that reduces tilting of ships and aircraft. It senses direction with a small gyroscope and counteracts rotation by adjusting the control surface or applying force to the large gyroscope. The process associated with this system is called Gyroscopic stabilization.

 

How does Gyroscopic Stabilization Work?

Gyro stabilization works by attaching a state-of-the-art FOG (fiber optic gyroscope) or MEMS (micro electromechanical system) gyroscope to the camera base to measure any movement that may occur. When the gyroscope senses motion, it sends commands to the pan/tilt unit to apply an opposing rotation to the camera to counteract that motion. This keeps the image on target even in the presence of large motion shifts (up to pan/tilt rotation limits). Performance depends on gyroscope accuracy, system latency, and pan/tilt motor speed and accuracy. These components can quickly become expensive, so we configure the camera individually for situation.

 

Before purchasing a gyro stabilization system, it is important to check the specifications of the pan/tilt system. This is because it must be able to operate quickly and accurately enough to stabilize the image. Not all gyro stabilization systems are created equal. The type of system need depends on intended use.

 

Parts of a Gyro

A gyro consists of 3 basic parts. flywheels, gimbals, and damping systems. The flywheel size and rotational speed determine a factor called angular momentum. A gimbal rotates the flywheel around an axis perpendicular to the axis of rotation. The speed at which the gimbal rotates (precession) as the boat rolls is a factor called angular velocity. The damping system controls how fast the gimbal can handle. Depending on the manufacturer, damping systems may be passive or active.

 

What are the advantages and disadvantages of gyroscopic stabilizer systems?

Gyroscopes have no appendage, are relatively small and compact, and are well designed to minimize the intense heat generated at the bearings by the rotating mass. Gyroscopes come in an attractive package and work well in many circumstances.

 

Disadvantages of gyro systems are that they are less efficient, are heavy, and in some cases service requires removing the unit from the ship. For a 30-knot boat, the gyro needs to be much larger—perhaps larger than the space allows—to match the performance of the Vector Fins, so sometimes two or three gyros will be installed. The systems can take up to an hour to "spin up" before providing full stabilization, they also generate noise, may require structural bracing and, with few exceptions, are completely dependent on AC power from a generator. In certain sea conditions, their effectiveness is also limited by the lift or precession distance, and when it is time to replace the main bearings, most gyroscopes must be removed from the ship and returned to the factory for repair.

 

 

Applications of Gyroscopic Stabilizations

Small, precise, and stable platforms are used in a variety of applications. These are especially useful for aiming subsystems such as cameras, laser range finders, radars, and antennas at specific targets while the mounted platform is in motion. Adapting a detection system from stationary to mobile use requires consideration of many criteria such as vibration and stabilization.

Mast & Tower

Just because a mast or tower is a solid structure attached to the ground does not mean it's perfectly stable. For example, the top of the Eiffel Tower in Paris can sway six to seven meters in the wind.

 

For mast and tower applications, gyro stabilization is recommended based on the distance and size of the target being tracked and the height and stability of the tower.

 

Vehicle

Expectations for in-vehicle cameras are very different. It can be affected by large movements, but I often work with a wider field of view, so I don't mind the effects of camera shake. Stabilization requirements vary depending on camera type, field of view, vehicle speed, and terrain conditions traversed.

 

Marine

A vessel on the ship experiences many movements, but this movement is a different type than a tower or an all-terrain vehicle. Ship-mounted cameras require varying degrees of gyro-stabilization, depending on the size of the ship and the field of view of the camera.

Pitching Case :

1.                 If bow of ship is down & stern is up , then Ship turns Right

2.                 If bow of ship is Up & stern is down , then Ship turns Left

Steering Case :

1.          When ship takes right turn , bow will go down & stern will go Up

2.          When ship takes Left turn , bow will go up & stern will go down

Robotics

It can be used in robots in order to balance them, if a robot knows it is falling it can be programmed to react. In this case with a little bit of programming a gyro would be able to inform a robot if it is falling over.

 

Airplanes

Gyroscope is used on almost all flight controller boards to give accurate measurements for the aircraft's orientation. It provides ease to keep a track of plane’s orientation mid-flight. This instrument can be used with further advancement to automate the flight system as to make an autopilot system for the aircraft.

 

 

Case 1 : Aeroplane takes Right Turn

   In this case Nose will go down & Tail will go Up

Case 2 : Aeroplane takes Right Turn

     In this case Nose will go Up & Tail will go down

 

REFERENCES:

1. The Gyroscope and it’s Applications by Dr. Ing Helmut Sorg

2. Gyroscope-Based Video Stabilization for Electro-Optical Long-Range Surveillance Systems - by Petar D. Milanović, Ilija V. Popadić and Branko D. Kovačević

3. https://www.infinitioptics.com/glossary/what-active-gyro-stabilization-and-why-it-important-long-range-ptz-cameras

4. S.S. Rathan (2009), Theory of Machines,3rd edition, Tata MC Graw Hill Education Pvt.td, New Delhi.

5. SadhuSingh (2012), Theory of Machines,3rd edition, Pearson, New Delhi.

 

 

 

 

Written By :

 

PRN No.	Name	Roll No
12010547	Harsh Rikame	1
12010299	Samarth Ikkalaki	6
12010965	Aditya Inamdar	7
12011087	Vaishnavi Jade	8
12011262	Kashyap Kadam	19