UNIT 2- Drone Stability and Control.ppt

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
•Duetothemassofthedrone,thebodymassforcealwaysacts
inthedirectionofgravity
•Highertheweightofthedrone,morepowerisrequiredtolift
andmovethedrone
•Weightofdrone=massofdrone×accelerationduetogravity

9. LIFT
•Theverticalforceactingonthedroneiscalledlift
•Thisforceisduetopressuredifferencesacrossthe
drone(intheverticaldirection).Hence,thespeed,
size,andshapeofthepropellerbladedecidethe
amountofliftforce
•Liftisessentialtoliftthebodyagainstthegravity

11. THRUST
•Theforceactingonthedroneinthedirectionof
motioniscalledthrust.

12. DRAG
•Theforceactingonthedroneintheopposite
directionofmotionduetoairresistanceiscalleddrag
•Thismaybebecauseofpressuredifferenceand
viscosityofair

14. PitchistheRotationofthedronealongtheLateralAxis(Y
Axis)
RollistheRotationofthedronealongtheLongitudinalAxis
(X-Axis)
YawistheRotationofthedronealongtheVerticalAxis.(Z-
Axis)
Axis System

16. Forces due to Torque

17. Equation of Motion
•DuringHoveringofDrone.WeightoftheDronemust
beequaltotheallupwardforcesofthepropellers.
•F
1+F
2+F
3+F
4=mg
•ForflyingUpwardforcemustbegreaterthanthe
weight.
•D
f=F
1+F
2+F
3+F
4–mg
•Moments=0

18. Climbing and Take-off
•D
f= F
1+ F
2+ F
3+ F
4 –mg > 0

19. Drooping, Descent or Falling
•D
f= F
1+ F
2+ F
3+ F
4 –mg < 0

21. DRONEMATERIALS
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:Hardnessreferstotheabilityofamaterialtoresistabrasion,
penetration,cuttingaction,orpermanentdistortion.
•Strength:Strengthistheabilityofamaterialtoresistdeformation.Strengthisalso
theabilityofamaterialtoresiststresswithoutbreaking.
•Density:RatioofMassandVolume.InAerospaceindustrylowdensitymaterials
arepreferred.
•Malleability:Itistheabilityofthematerialtorolled,pressedandhammered.Itis
definedastheplasticresponsetocompressiveload.
•Ductility:Itisthepropertyofametalwhichpermitsittobepermanentlydrawn,
bent,ortwistedintovariousshapeswithoutbreaking.Itisdefinedastheplastic
responsetotensileload.
•Elasticity:Itisthatpropertythatenablesametaltoreturntoitsoriginalsizeand
shapewhentheforcewhichcausesthechangeofshapeisremoved.
8/20/2023
Dept of Aeronautical Engineering

25. •Toughness:Itisdefinedastheamountofenergyabsorbedbyabody
duringdeformation.ItisoneofthedesirablepropertyofanAerospace
material.
•Brittleness:Brittlenessisthepropertyofametalwhichallowslittle
bendingordeformationwithoutshattering.Abrittlemetalisapttobreakor
crackwithoutchangeofshape.Becausestructuralmetalsareoften
subjectedtoshockloads,brittlenessisnotaverydesirableproperty.
•Fusibility:Fusibilityistheabilityofametaltobecomeliquidbythe
applicationofheat.Metalsarefusedinwelding.Steelsfusearound2600°F
andaluminumalloysatapproximately1100°F.
8/20/2023
Dept of Aeronautical Engineering

26. 4
• Tensilestress, s: • Shearstress, t:s
F
t
A
o
original area
before loading
Stress has units:
N/m
2
or lb/in
2
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 centerlayer. The facings are made up of several
layers of glass cloth, bonded together with a liquid resin. The core material
(centerlayer) 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. Mostcompositesconsistofabulkmaterial(the‘matrix’),anda
reinforcement,addedprimarilytoincreasethestrengthandstiffnessofthe
matrix.Thisreinforcementisusuallyinfibreform.
Today,themostcommonman-madecompositescanbedividedintothreemain
groups:
PolymerMatrixComposites(PMC’s)–Thesearethemost
commonandwillbediscussedhere.AlsoknownasFRP-FibreReinforced
Polymers(orPlastics)–thesematerialsuseapolymer-basedresinasthematrix,
andavarietyoffibressuchasglass,carbonandaramidasthereinforcement.
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).
CeramicMatrixComposites(CMC’s)-Usedinveryhigh
temperatureenvironments,thesematerialsuseaceramicasthematrixandreinforceitwith
shortfibres,orwhiskerssuchasthosemadefromsiliconcarbideandboronnitride(BN).

33. DRONE FRAME
•Basically,thedroneframeisthemostimportanttobuildadrone.Ithelpstomount
themotors,battery,andotherpartsonit.Ifyouwanttobuildacopteroraglide,
youfirstneedtodecidewhatframeyouwillbuyorbuild
.
Carbon Fiber
Acrylic Plastic
Metallic Alloys