Gyroscope

DESIGN FABRICATION, STUDY AND ANALYSIS OF A GYROSCOPE

Project Advisor : Mr. Waqar Ahmed Qureshi Team Members: Ahsan Ahmad (09ME70) Muhammad Umar (09ME84) Sarmad Mukhtar (09ME110)

DEPARTMENT OF MECHANICAL ENGINEERING, UNIVERSITY OF ENGINEERING AND TECHNOLOGY, TAXILA, PAKISTAN.

GYROSCOPE: “gyro means revolution and skopien means

to view” DEFINITION: Any rotating mass is a gyroscope.

Gyroscope means simply any body exhibiting gyration or rotation.

A gyroscope is a device for measuring or

maintaining orientation, based on the principles of angular momentum.

DEFINITION CONT…

A mechanical device the essential part of

which is a flywheel having a heavy rim and so mounted that, while spinning at high speed . the axis of rotation can turn in any direction about a fixed point on that axis.

TYPES OF GYROSCOPES: Following are the main types of gyroscopes:

Mechanical gyroscopes Gas Bearing gyroscopes Optical gyroscopes MEMS gyroscopes

We have selected the Mechanical gyroscope for the project.

PARTS OF A GYROSCOPE: Following are the essential parts of a

gyroscope: Disc (Gyro wheel/Flywheel) Gimbals Base Circuitry/driving source

GIMBALS: Simply “A gimbal is a ring” It is a pivoted support that allows

the rotation of an object about a single axis.

Most gimbal systems look like a series of concentric rings.

GIMBAL SHAPES: Gimbals can be of any shape they might be Circular Spherical(hollow) Rectangular/square Half of any shape

Actually the basic point is to hold and allow

rotation about an axis . It doesn’t depends on the shape of the gimbal.

GIMBALS ASSEMBLY: The outermost ring mounts to the base.

The next largest ring connects to the outermost ring at two points that are perpendicular to the outer ring's surface mount, and so on..

1 axis 2 axis 3 axis

GIMBALS ASSEMBLY CONT. A set of three gimbals, one mounted on

the other with orthogonal pivot axes i.e. at 90 degree to one another., may be used to allow an object mounted on the innermost gimbal to remain independent of the rotation of its support.

GIMBALS APPLICATIONS: They are used everywhere from satellites to a

simple fan.Some of its applications worth seeing are:

Movement in space Cameras Swings

DISC/GYRO: A solid body capable of rotating at

higher angular velocity about an instantaneous axis which always pass through a fixed point.the fixed point may be the cenre of gravity of the solid or it may be another point.

CHARACTERISTICS OF THE GYRO DISC:

The following characteristics must be controlled accordingly if we want to have a desirable output from the gyro wheel:

Distribution of weight Weight Speed /Angular momentum/ moment of

inertia

SHAPE OF THE GYRO DISC: The shape of gyro disc which is most suited

for the characteristic behaviour is short listed to be like this:

USE OF GYRO DISC: The gyro disc is used in the system to: Have a high spin angular momentum High moment of inertia More precession High stability/rigidity Least vibrations

BASE: The base of the system is for the following

purposes: Mounting the outer most gimbal Absorbs the vibrations of system To deliver any applied force to the gimbals

CIRCUITRY/POWER SOURCE: The disc of the gyroscope needs spin , and to

give it either some installed motor is needed or some external source which give it the required spin.

GYROSCOPE ASSEMBLY:

ALLOWED MOVEMENTS:

GYROSCOPIC PHENOMENA: The gyroscope shows two types of

phenomema: Rigidity Precession

RIGIDITY: It can be described as: The axis of rotation (spin axis) of the

gyro wheel tends to remain in a fixed direction in space if no force is applied to it.

Gyro rigidity is the strength with

which a gyro resists any external force that would tilt its rotor spin axis.

FACTORS OF RIGIDITY: Rigidity of a gyroscope depends on the

following factors: Weight of the rotor Distribution of this weight Rotor speed

INCREASING RIGIDITY: Rigidity is increased but under certain limits: High angular velocity Heavy weight Disc should be having most weight at

edges

INSIGHT: High spin velocity> high angular velocity

> high angular momentum > more resistance to external forces

High mass > high torque needed to rotate it

>more angular momentum > more resistance to external forces

High mass at ends > high rigidity

PRECESSION: It can be defined as: The axis of rotation has a tendency to

turn at a right angle to the direction of an applied force.

The effect that we got as result of interaction between spin angular momentum and the external torque/couple or rotation is called as precession.

PRECESSION CONT.

PRECESSION IN BOTH DIRECTIONS: Whenever a body is rotating or spinning in a

plane (plane YZ) about an axis (axis OX) and its axis of rotation or spin is made to precess in an another perpendicular plane (plane XZ),the couple is induced on the rotating or spinning body across the axis of rotation or spin in a third mutually perpendicular plane (plane XY).

Conversely, whenever a body is rotating in a

plane (plane YZ) about an axis (axis OX) and a couple is applied on the rotating body across the axis of rotation or spin in an another perpendicular plane (plane XY), the rotating or spinning body starts processing in a third mutually perpendicular plane (plane XZ).

FACTORS IN PRECESSION: Precession depends on the following factors:

Spin velocity Weight of rotor Distribution of mass/shape

PRECESSION INCREASING FACTORS:

Following factors effect the magnitude of precession:

Spin velocity of rotor Shape/ weight distribution Weight of rotor

INSIGHT: Low spin velocity > low angular velocity >

low spin angular momentum > high precession

Low weight > low torque needed to rotate it > low spin angular momentum > high precession

Poor weight distribution > less rigidity > high precession

(spin angular momentum should remains many folds higher than the external torque)

CONCLUDING THE PHENOMENA: Precession and rigidity both depends on the

same factors but the action is opposite : “A high rigidity results in a very slow

precession” We cannot compromise on the rigidity or the

precession so we have to balance all the 3 factors to have a sound rigidity and a measurable precession.

SOME PHENOMENA/PROBLEMS RELEVANT TO GYROSCOPES:

There are some very interesting phenomena relevant to the gyroscopes:

Nutation Gimbal Lock Balancing

NUTATION: Nutation is a rocking, swaying, or nodding

motion in the axis of rotation of a largely axially symmetric object.

It can be controlled by proper balancing,

controling the surface features etc

GIMBAL LOCK: Gimbal lock occurs when two axes in a

three-gimbal system align "locking" the system into rotation in a degenerate two-dimensional space.

A motor to unlock the system or a fourth

gimbal is added.

BALANCING: The balancing of the system means that all

the gimbals are free about their axis of rotation with no weight/torque due to mounting.

The shaft of the disc must not experience

any force itself.

DESIGNING: The designing of the gyroscope took three

steps until its present shape: Selection of design Hand sketching Pro-E design

SELECTION OF DESIGN: The selection of design is dependent on

factors like : Available parts Available/Feasible material Machining processes possible Time available Optimization

ROUGH/ HAND DESIGNING: The first step is to make the parts and the

decided parameters by hand and to do all the required changes for betterment.

PRO-E DESIGN: In the next step the whole model is

translated to a software to observe the system in 3 dimensional state and to further refine the model.

FULL VIEW:

FABRICATION: For the fabrication of the project the model was

divided into 3 parts: Gimbals Gyro disc and shaft Base Assembly parts(pins,bearings,washers,bushes)

FABRICATION CONT. The operation machines involves are Gimbals(Bending, Grind, Lathe) Gyro disc and shaft (Lathe, Drill, Grind) Base (Grind, Drill, Shaper) Assembly parts (Welding, Fits, Fastening)

ANALYSIS: The analysis of the project comprises of two

steps: Design Analysis Gyroscopic effect Analysis

DESIGN ANALYSIS: This analysis comprises of the excel formula

and parametric sheet for all the design parameters of the model. And we can check by changing anyone of them, the effect on all relevant features.

GYRO ANALYSIS: It comprises of the analysis of the formula

sheet of the relevant terms of gyroscope and we can check the effect of change in one on others.

.

FUTURE HORIZONS: This project can be took forward to

various applications like: Target locking systems Inertial guidance systems Inertial navigation systems Compasses

APPLICATIONS IN DAILY LIFE: The most common examples of gyroscopic

effects in daily life are the spinning tops, the gyroscopic compasses, and the military systems like radar.