Micro Air Vehicles Dr. S. S. Gokhale NIT-Calicut.
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Transcript of Micro Air Vehicles Dr. S. S. Gokhale NIT-Calicut.
Micro Air VehiclesMicro Air Vehicles
Dr. S. S. GokhaleNIT-Calicut
100 years ago100 years ago
1903-First Flight, Wright Brothers
12 hp Engine + Pusher Propeller & 318 kg Biplane
12 second flight, 120 ft distance & 10 ft altitude
MustangMustang
Jump Jet HarrierJump Jet Harrier
Civilian Objectives & GoalsCivilian Objectives & Goals
Higher, Faster, Longer Distances, - Personal Thrill
Cheaper, Safer, Reliable – Passenger Comforts
Economical, Easy to Maintain, Spare Part Access, Hanger/Runway Restrictions – Airline Operators
Familiar Layout, Less Retraining – Pilots, Crew
Military Objectives & GoalsMilitary Objectives & Goals
Speed, Maneuverability, Assorted Devastating Payload, Stealth ness
Ergonomic and Human Factors associated with Pilot- Blackout, Redout in High g Environment, Oxygen Mask, Ejection Seat etc.
Inherently unstable system requiring higher level of flying skill
Civilian- Boeing -777Civilian- Boeing -777
Passenger 300+ Cargo 150 cu m Fuel 195 kL TO Wt. 340 T Range 16400 km M 0.84, Alt. 10.7 km (LxWxD) 64x65x6.2
m Engine 2 x 50 T 18 hr flight
Military- B-2 StealthMilitary- B-2 Stealth
TO Wt. 150 T Payload 18 T Engine 4 x 7.8 T High Subsonic
Cruise, 15 km Alt. Range 9600 km (LxWxH) 21x52x5 m Low Operability Multi Role Bomber
Military- Raptor F-22Military- Raptor F-22
Air-Dominance Fighter
(LxWxH) 19x13.4x4.8 m
Mach 2 Sustainable Engines 2 F119 PW-
100 TF Engines with ~ 16 T thrust
Projected Date of Operation 2005
Century in Perspective Century in Perspective Strength Weakness Opportunit
yThreat
I Quarter CuriosityChallenge
In-depth KnowledgeMtl./Manuf.Engine Power
Military Applications
Jealousy
II Quarter Race for SupremacyResearch
Mtl./Limited IC Engine Power/Propeller
MilitaryGT EngineCommercial?
SuspicionSecrecy
III Quarter CommercialCompositesComputers
Relative War Free Period
Cutting Edge TechnologySpace Race
Espionage
IV Quarter Customer FocusIT, Biotech
Uni-polar World
GlobalizationVast Array of a/c
Cut Throat Competition
Birds and BeesBirds and Bees
Bird’s 3 Basic Motion Flapping-Tilting Lift
forward for Thrust Twisting TE-Adjust
Angle of Attack for Optimum Lift
Folding-Wing span Variation for Minimum Drag
Unsteady Flow-More Lift + Acceleration
Insect with Four Equal Sized Wings
Flapping is out of Phase between the Front and the Rear
Wings- Foldable underneath when not in use
High Amplitude, High Frequency Oscillations
Man v/s Bird – No Man v/s Bird – No ComparisonComparison
Man’s arm has 29 bones
It is a complex structure meant for dexterity & can perform skill jobs
It has reasonably poor strength
Birds arm has only 11 bones which are much longer and are fused together.
These are much simpler with fewer joints involving fewer movements & hence rigid.
Stronger wings provide Lift + Thrust
BirdsBirds
Perfectly controlled natural flying machine (8600 species)
Feathers: Light strong, flexible
Two legs: Hopping & Claws Difficult Landing
Adaptive: Body Organs Internalized
Bustard: 10kg/1.2 m W Falcon: 160-320 kmph
Wing ShapeWing Shape
Feathers give peculiar shape to the wings. The form & function of the same is directly correlated.
Birds which fly fast in open air have long narrow wings. These birds experience difficulty during take-off but have long sustaining power. Wing flapping between 60-100 times in an hour depending on calm or rough weather.
Woodland birds fly slowly but are extremely maneuverable. These birds have short broad wings with wide feathers.
Marvin Minsky developed the Tentacle Arm, which moved like an octopus. It had twelve joints designed to reach around obstacles. A PDP-6 computer controlled the arm, powered by hydraulic fluids. Mounted on a wall, it could lift the weight of a person.
Large InsectsLarge Insects
Flapping 100~1000/s Flapping: up/down &
forward/backward Thorax power sources
for wings & legs Skeleton provides
weather protection Ultra-light wing
structure Static Hovering
Hummingbirds are quite small with a length of only 2 ¼ in to 8 ½ in, however, they are not the smallest of all birds. They eat the nectar of flowers for survival and can consume up to half their weight in sugar daily. The reason for this enormous appetite is the hummingbird’s extraordinary flight capability.
The disadvantage of hovering is the excessive energy required for its success. The excessive energy requires the hummingbird to consume a lot of food. The energy output of a hummingbird in hovering flight is ten times as much as a man running nine miles an hour. Direct comparisons to a human being show that a 170-pound man would have to consume about 130 pounds of bread to keep up with a hummingbird’s energy-output
University of Texas Project to Study Hummingbird - MAV
Figure "8" motif the wingtips of the hummingbird trace in the air while hovering, as well as the wing patterns at various positions. Notice the change in the pitch attitude of the hummingbird as the speed of the bird changes from top speed to hovering.
Basic Equipment used in research: HS Camera, CT Scanner, Frame grabber, MSC/NASTRAN Software, Computer, Photo-Imaging Tools, Aero-elastic Analysis
At the sizes envisioned for these devices, normal aerodynamic rules no longer apply. Micro-flyers will have to operate in an environment more common to small birds and large insects than that of larger aircraft. The forces associated with air moving around the tiny devices are more pronounced than with conventional aircraft in flight, causing increased drag, reduced lift under the smaller wings at low speeds, and decreased propeller efficiency. Such aircraft, weighing only 50 grams, are more susceptible to wind gusts, updrafts, and rain. Other challenges include developing tiny sensors, engines, and power sources for such planes, as well as communications, control and navigation systems for the tiny robot aircraft, which would have to operate with little or no human input. Micro-flyers require an entirely new approach to aircraft design and miniaturization. As flying objects become smaller, the viscosity of the air becomes increasingly important because for the smallest insects, flying is more like swimming through honey. Micro-wings are also susceptible to boundary layer separation. Small changes in the angle of flight can result in extreme loss of lift
Flight BasicFlight Basic
Weight: Gravity - Default
Thrust: Machine / Muscle Power
Lift & Drag: Aerodynamic forces due to Motion
Level & Un accelerated Flight: L = W and T = D
Flight Control due to unbalanced forces
L/D and T/WL/D and T/W
L/D T/W
Birds/Insects ~ 20 ~ 0.2 - 0.3
Gliders ~ 20-35 0
Aircraft ~ 15-20 (commercial)
~ 4-10 (military)
~ 0.2 - 0.3
~ 1.2 - 6
Human Powered FlightHuman Powered Flight
Paul McCready June 79
English Channel Crossing- 22 miles in 2 hrs 49 min (12.5 kmph)
31 m Wing-Span and 31.5 kg weight
50000 UKP Kramer Competition
500 m equilateral triangle clock and anticlockwise in 7 minutes
Flt. Speed 10 m/s, Altitude 5 m in a wind speed of 5 m/s at 10 m Alt.
RPV & UAVRPV & UAV Tactical Reconnaissance
& Surveillance, Missile Simulation
2 Stroke, 4 Cylinder, 24 hp engine + Carbon Propeller or Turbojet
(WxLxH) 2.6x3x2.2 m TO 75 kg, Payload 20 kg,
CCD Camera Max Speed 320 kmph Cruise 80 kmph Alt. 3km, 50 km Radius Guidance Remote+GPS
RPV & UAVRPV & UAV
Airborne Experiments Wing 1.75 m Wing Area 0.52 sq m Weight ~ 3 kg Cargo 1.4x3x1.2 cm 200 g fuel, 1.15 L, 1
hp, 2 cycle engine 72 MHz FM
Transmitter/ Receiver Video Camera
Autonomous Helicopter Autonomous Helicopter ApplicationsApplications
Search and Rescue
Quick and Systematic Search
Lock Position and follow it up
Autonomous Helicopter Autonomous Helicopter ApplicationsApplications
Surveillance Patrol Area for
Unusual Activity Day & Night
Operations
Autonomous Helicopter Autonomous Helicopter ApplicationsApplications
Law Enforcement High Speed Chase Assistance to
Police
Autonomous Helicopter Autonomous Helicopter ApplicationsApplications
Aerial Mapping More Accurate
Topological Map Altitude v/s Area
of Coverage v/s Resolution
Autonomous Helicopter Autonomous Helicopter ApplicationsApplications
Cinematography Entertainment
MAV Design PhilosophyMAV Design Philosophy
Robots with High Level of AutonomyMinimum External Resource
DependenceMount System Power, Sensors,
Controls, Computers on BoardChoice Driven by Weight, Cost,
Power ConsumptionBehavior based Control Approach
MAV Goal MissionMAV Goal Mission
Auto Start and Take OffFly to designated Area on Prescribed
Path Avoiding ObstaclesLock on Target and PursueSend Information, Images back
HomeSafe LandingAll Weather Flying Capability
MAV- Main CharacteristicsMAV- Main Characteristics(L / W / H) – Not to Exceed 15 cmWeight 50 g, Payload 20 gSpeed 35-75 kmphCruise Altitude 70 – 100 mRange 10 kmFlight Duration 20 – 60 minutesSix Degree Freedom Aerial Robots
Technology FeasibilityTechnology Feasibility
Micro-ElectroMechanical Systems (MEMS)
Integrated Multifunctional System-Sensors, Actuators, Micro-processors
Micro-fabrication TechniquesLow-Cost Production PotentialFast Processors, Smaller Storage
Devices
Innovative Solution Innovative Solution NeededNeeded
AerodynamicsControlPropulsion and PowerNavigationCommunicationSmart Structures
AerodynamicsAerodynamics
Reynolds Number = ( u L) /, Limited knowledge at Low Re
Low AR- 3-D Effects Agility, Range, Flt. Dyn.
Observations for Bird, Insect Limited
Mechanizing flight at low Re Difficult
Unconventional Wings and Movement
Rotary WingRotary Wing
Low Speed & Hovering Capabilities
Possible use in Data Collection on Mars Mission
Easily Scalable Useful in studying
Wind-Shear
Flapping WingFlapping Wing
Imitating Birds Induced Vortex
Generation Electric Impulse
to Elastomer Actuators causes Contraction and Relaxation
Adaptive Wings
Reconnaissance MissionReconnaissance Mission
Situation Awareness at platoon Level
Real Time Day-Night Imagery
MAV Relocating at Vantage Points
Unattended surface sensors from Imagery to Seismic Detection
Urban Operation MissionUrban Operation Mission
Reconnaissance and Surveillance of Inner City Areas
Ability to Navigate Complex Shaped Passages
Avoid Obstacles Relay Information
back to Manage Urban Disaster / Terrorism
Biochemical SensingBiochemical Sensing
Gradient Sensors and Flight Control Feedback to Map Size of Hazardous Clouds
Provide Real Time Tracking Information
MAV ApplicationsMAV Applications
Packed with Ejector Seat Mechanism of Aircraft-Sends Signals about Downed Pilot
MAV could be used for Traffic Monitoring, Border Surveillance, Fire and Rescue Operations, Forestry, Wild-Life Survey, Power Line Inspection, Aerial Photography
MAV can Provide targeting Information & Battle Damage Assessment
Barrel or Overhead Flight Vehicle Launch is Possible
MAV System IntegrationMAV System Integration MEMS based
Components Individual Components
Occupy More Space On-board Processor &
Communication Electronics- MAV Core
Critical Link between Major Subsystems is Important
Multifunctional use & Synergy is Crucial
PropulsionPropulsion
Low Re -> L/D~1/3-1/4 -> Need More Power
Small Propellers have Poor Efficiency
Realized Power is Less
Higher Energy Density is Necessary
Battery Technology -> Fuel Cell Use
MAV Control Guidance MAV Control Guidance CommunicationCommunication
Current GPS is Too Heavy and Power Intensive
Human Responses for Enhanced Agility are Slow
Miniaturized and Advanced Navigation, Guidance and Control need to be Developed
MAV PayloadMAV Payload
Sensors-Optical,, IR, Acoustic, Bio-chemical, Nuclear
Visible Imaging System-1 cu cm Camera Weighing 1 g with 1000x1000 pixels and requiring 0.25 milliwatt power
Mature Technology is Available
MIT Concept of MAVMIT Concept of MAV
8 cm vehicle with 10 g weight & total power requirement of 1 watt
Propulsion needs 90% of Total Power and takes 70% of Total Weight
Forward mounted Video System looking down at 45 degree at 2 frames/s
Smart Structure: EntomopterSmart Structure: Entomopter
Mechanical Insect Reciprocating Chemical
Muscle (RCM) Generating autonomic
wing beating from a chemical energy source Adaptive Wing Concept
Self Repairing Structures & Nano- Technology
Through direct conversion, RCM provides small amounts of electricity for onboard systems
Robert Michelson, Georgia Tech Research Institute
Weight IssuesWeight Issues
Small Size -> High Surface to Volume Ratio
Constraints on Weight and Volume
Develop and Integrate Physical Elements & Components
Multifunctional amongst System Components
Presently, work is progressing to develop the wings for the Mars Entomopter. Stereo-lithography and Fused Deposition Modeling techniques have allowed Michelson's design team to create intricate wing structures directly from computer models. Careful attention is being paid to material selection. Resilience, stiffness in opposite planes, chemical compatibility, and ease of bonding are but a few of the points to be considered in choosing wing materials. Wings have been grown in our stereo-lithography machines as well as ABS wing stiffening structures produced using Fused Deposition Modeling (FDM) methods with, and without interstitial materials. The interstitial material has been placed over the flexible wing structure to demonstrate that micro-channel ribs can be produced to create a wing that can distribute gas to portions of the wing for active flow control to increase lift and produce attitude control moments. Later wing designs are greatly simplified with a single "spar channel" encased in a composite thin wing.
Researchers from the Departments of Aerospace & Mechanical Engineering and Electrical & Computer Engineering at the University of Florida are doing on-going work on vision-guided autonomous flight for Micro Air Vehicles (MAVs).
Indian EffortsIndian Efforts
Indians involved in Research in MAV in USA (MIT, Georgia etc.)
NAL, IISc, IITs carrying out Elementary Experimental and Simulation Work
Commitment from Raksha Mantralaya as a Priority Area
Lot more needs to be done Rudimentary MEMS Work Undertaken in
a Few places
Flow past two impulsively started cylinders at Re=550 (15 seconds).Ph.D. Work of Prabhu Ramachandran, Dept. of ASE, IIT-Madras.
IIT-M Efforts: CFD SimulationIIT-M Efforts: CFD Simulation
5 degrees
10 degrees
15 degrees
Flow Past Flat Plate at an Angle of Attack (Re=1000). Simulation time 10s.
Ph.D. Work of Prabhu Ramachandran, Dept. of ASE, IIT-Madras
Flow past an oscillating flat plate. Work done at Cal. Tech.
Concept - Using thermoelectric generator modules to convert Concept - Using thermoelectric generator modules to convert engine waste heat energy to useful electric energy for micro engine waste heat energy to useful electric energy for micro
air vehicles air vehicles Result - An enabling technology for extending the endurance Result - An enabling technology for extending the endurance
and mission capabilities of micro air vehicles.and mission capabilities of micro air vehicles.Fleming, J. L., Ng, W. F., and Ghamaty, S., "Thermoelectric-Fleming, J. L., Ng, W. F., and Ghamaty, S., "Thermoelectric-
Based Power System for UAV/MAV Applications", AIAA Paper Based Power System for UAV/MAV Applications", AIAA Paper 2002-3412, Unmanned Aerospace Vehicles, Systems, 2002-3412, Unmanned Aerospace Vehicles, Systems,
Technologies, and Operations Conference and Workshop, Technologies, and Operations Conference and Workshop, Portsmouth, VA, May 20-23, 2002.Portsmouth, VA, May 20-23, 2002.
Small Is Beautiful