drone stability and control, drone motions

1. INTRODUCTION TO DRONE
TECHNOLOGY
Mr. Vishnu Raj
Assistant Professor
Department of Aeronautical Engineering
Unit 2: Drone Stability and Control, Material Selection

2. BASICS

3. MOMENT

4. RESULTANT FORCE

5. CENTRE OF GRAVITY

6. STABILITY AND UNSTABILITY

7. FORCES ACTING ON A UAV

8. WEIGHT
• Due to the mass of the drone, the body mass force always acts
in the direction of gravity
• Higher the weight of the drone, more power is required to lift
and move the drone
• Weight of drone = mass of drone × acceleration due to gravity

9. LIFT
• The vertical force acting on the drone is called lift
• This force is due to pressure differences across the
drone (in the vertical direction). Hence, the speed,
size, and shape of the propeller blade decide the
amount of lift force
• Lift is essential to lift the body against the gravity

11. THRUST
• The force acting on the drone in the direction of
motion is called thrust.

12. DRAG
• The force acting on the drone in the opposite
direction of motion due to air resistance is called drag
• This may be because of pressure difference and
viscosity of air

14.  Pitch is the Rotation of the drone along the Lateral Axis (Y
Axis)
 Roll is the Rotation of the drone along the Longitudinal Axis
(X-Axis)
 Yaw is the Rotation of the drone along the Vertical Axis.(Z-
Axis)
Axis System

16. Forces due to Torque

17. Equation of Motion
• During Hovering of Drone. Weight of the Drone must
be equal to the all upward forces of the propellers.
• F1 + F2 + F3 + F4 = mg
• For flying Upward force must be greater than the
weight.
• Df = F1 + F2 + F3 + F4 – mg
• Moments = 0

18. Climbing and Take-off
• Df = F1 + F2 + F3 + F4 – mg > 0

19. Drooping, Descent or Falling
• Df = F1 + F2 + F3 + F4 – mg < 0

21. DRONE MATERIALS
1. Basic requirements
• High strength and stiffness
• Low density
=> high specific properties e.g. strength/density, yield
strength/density, E/density
• High corrossion resistance
• Fatigue resistance and damage tolerance
• Good technology properties (formability, machinability, weldability)
• Special aerospace standards and specifications
2. Basic aircraft materials for airframe structures
• Aluminium alloys
• Magnesium alloys
• Titanium alloys
• Composite materials

22. F

bonds
stretch
return to
initial
2
1. Initial 2. Small load 3. Unload
Elastic means reversible!
ELASTIC DEFORMATION

23. 3
1. Initial 2. Small load 3. Unload
Plastic means permanent!
F

linear
elastic
linear
elastic
plastic
PLASTIC DEFORMATION
(METALS)

24. MECHANICAL PROPERTIES OF MATERIALS
• Hardness: Hardness refers to the ability of a material to resist abrasion,
penetration, cutting action, or permanent distortion.
• Strength: Strength is the ability of a material to resist deformation. Strength is also
the ability of a material to resist stress without breaking.
• Density: Ratio of Mass and Volume. In Aerospace industry low density materials
are preferred.
• Malleability: It is the ability of the material to rolled, pressed and hammered. It is
defined as the plastic response to compressive load.
• Ductility: It is the property of a metal which permits it to be permanently drawn,
bent, or twisted into various shapes without breaking . It is defined as the plastic
response to tensile load.
• Elasticity: It is that property that enables a metal to return to its original size and
shape when the force which causes the change of shape is removed.
8/20/2023
Dept
of
Aeronautical
Engineering

25. • Toughness: It is defined as the amount of energy absorbed by a body
during deformation. It is one of the desirable property of an Aerospace
material.
• Brittleness: Brittleness is the property of a metal which allows little
bending or deformation without shattering. A brittle metal is apt to break or
crack without change of shape. Because structural metals are often
subjected to shock loads, brittleness is not a very desirable property.
• Fusibility: Fusibility is the ability of a metal to become liquid by the
application of heat. Metals are fused in welding. Steels fuse around 2600 °F
and aluminum alloys at approximately 1100 °F.
8/20/2023
Dept
of
Aeronautical
Engineering

26. 4
• Tensile stress, s: • Shear stress, t:
s 
Ft
Ao
original area
before loading
Stress has units:
N/m2 or lb/in2
ENGINEERING STRESS

27. Stress Strain Diagram for Ductile
Material
8/20/2023
Dept
of
Aeronautical
Engineering

28. Monolithic
Materials
Hybrids
Ceramics and ceramic alloys
& Glasses
Metals
(& Metallic Alloys)
Polymers (& Elastomers)
Sandwich
Composite
Lattice
Segment
Composites: have two (or more) solid
components; usually one is a matrix and
other is a reinforcement
Sandwich structures: have a
material on the surface (one or
more sides) of a core material
Lattice* Structures: typically a combination
of material and space
(e.g. metallic or ceramic forms)
Segmented Structures: are divided in 1D, 2D or 3D
(may consist of one or more materials).
Hybrids are designed
to improve certain
properties of
monolithic materials
Classification of composites.
 Based on the matrix: metal matrix, ceramic matrix, polymer
matrix.
 Based on the morphology of the reinforcement: particle reinforced
(0D), fiber reinforced (1D), laminated (2D).
Prabu G

29. Reinforced plastic
• Reinforced plastic is used in the construction of radomes, wingtips,
stabilizer tips, antenna covers, and flight controls. Reinforced plastic has a
high strength to weight ratio and is resistant to mildew and rot. Because it is
easy to fabricate, it is equally suitable for other parts of the aircraft.
• Reinforced plastic is a sandwich type material (fig. 4-4). It is made up of
two outer facings and a center layer. The facings are made up of several
layers of glass cloth, bonded together with a liquid resin. The core material
(center layer) consists of a honeycomb structure made of glass cloth.
• Reinforced plastic is fabricated into a variety of cell sizes.

30. Rubber
• Rubber is used to prevent the entrance of dirt, water or air, and to prevent the loss of
fluids, gases, or air. It is also used to absorb vibration, reduce noise and cushion impact
loads. The term “Rubber” is as all inclusive as the term “metal”. It is used to include not
only natural rubber, but all synthetic and silicone rubbers.
• Natural rubber has better processing and physical properties than synthetic or silicon
rubber. These properties include :
• 1. Flexibility
• 2. Elasticity
• 3. Tensile strength
• 4. Tear strength
• 5. Low heat build up due to flexing (hysteresis)
Synthetic rubber is a available in several types, each of which is compounded
of different materials to give the desired properties
Synthetic Rubber

31. Composite Materials

32. Most composites consist of a bulk material (the ‘matrix’), and a
reinforcement, added primarily to increase the strength and stiffness of the
matrix. This reinforcement is usually in fibre form.
Today, the most common man-made composites can be divided into three main
groups:
Polymer Matrix Composites (PMC’s) – These are the most
common and will be discussed here. Also known as FRP - Fibre Reinforced
Polymers (or Plastics) – these materials use a polymer-based resin as the matrix,
and a variety of fibres such as glass, carbon and aramid as the reinforcement.
Metal Matrix Composites (MMC’s) - Increasingly found in the
automotive industry, these materials use a metal such as aluminium as the matrix, and
reinforce it with fibres such as silicon carbide (SiC).
Ceramic Matrix Composites (CMC’s) - Used in very high
temperature environments, these materials use a ceramic as the matrix and reinforce it with
short fibres, or whiskers such as those made from silicon carbide and boron nitride (BN).

33. DRONE FRAME
• Basically, the drone frame is the most important to build a drone. It helps to mount
the motors, battery, and other parts on it. If you want to build a copter or a glide,
you first need to decide what frame you will buy or build
.
 Carbon Fiber
 Acrylic Plastic
 Metallic Alloys