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Micro Air Vehicles

Micro Air Vehicles . Dr. S. S. Gokhale NIT-Calicut. 100 years ago. 1903-First Flight, Wright Brothers 12 hp Engine + Pusher Propeller & 318 kg Biplane 12 second flight, 120 ft distance & 10 ft altitude. Mustang. Jump Jet Harrier. Civilian Objectives & Goals.

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Micro Air Vehicles

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  1. Micro Air Vehicles Dr. S. S. Gokhale NIT-Calicut

  2. 100 years ago • 1903-First Flight, Wright Brothers • 12 hp Engine + Pusher Propeller & 318 kg Biplane • 12 second flight, 120 ft distance & 10 ft altitude

  3. Mustang

  4. Jump Jet Harrier

  5. Civilian 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

  6. Military 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

  7. Civilian- 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

  8. Military- 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

  9. Military- 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

  10. Century in Perspective

  11. 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 Birds and Bees

  12. 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 Man v/s Bird – No Comparison

  13. Birds • 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

  14. Wing 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.

  15. 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.

  16. Large 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

  17. 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

  18. 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

  19. 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

  20. Flight 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

  21. L/D and T/W

  22. 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. Human Powered Flight

  23. RPV & 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

  24. RPV & 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

  25. Autonomous Helicopter Applications • Search and Rescue • Quick and Systematic Search • Lock Position and follow it up

  26. Autonomous Helicopter Applications • Surveillance • Patrol Area for Unusual Activity • Day & Night Operations

  27. Autonomous Helicopter Applications • Law Enforcement • High Speed Chase • Assistance to Police

  28. Autonomous Helicopter Applications • Aerial Mapping • More Accurate Topological Map • Altitude v/s Area of Coverage v/s Resolution

  29. Autonomous Helicopter Applications • Cinematography • Entertainment

  30. MAV Design Philosophy • Robots with High Level of Autonomy • Minimum External Resource Dependence • Mount System Power, Sensors, Controls, Computers on Board • Choice Driven by Weight, Cost, Power Consumption • Behavior based Control Approach

  31. MAV Goal Mission • Auto Start and Take Off • Fly to designated Area on Prescribed Path Avoiding Obstacles • Lock on Target and Pursue • Send Information, Images back Home • Safe Landing • All Weather Flying Capability

  32. MAV- Main Characteristics • (L / W / H) – Not to Exceed 15 cm • Weight 50 g, Payload 20 g • Speed 35-75 kmph • Cruise Altitude 70 – 100 m • Range 10 km • Flight Duration 20 – 60 minutes • Six Degree Freedom Aerial Robots

  33. Technology Feasibility • Micro-ElectroMechanical Systems (MEMS) • Integrated Multifunctional System-Sensors, Actuators, Micro-processors • Micro-fabrication Techniques • Low-Cost Production Potential • Fast Processors, Smaller Storage Devices

  34. Innovative Solution Needed • Aerodynamics • Control • Propulsion and Power • Navigation • Communication • Smart Structures

  35. Aerodynamics • 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

  36. Rotary Wing • Low Speed & Hovering Capabilities • Possible use in Data Collection on Mars Mission • Easily Scalable • Useful in studying Wind-Shear

  37. Flapping Wing • Imitating Birds • Induced Vortex Generation • Electric Impulse to Elastomer Actuators causes Contraction and Relaxation • Adaptive Wings

  38. Reconnaissance Mission • Situation Awareness at platoon Level • Real Time Day-Night Imagery • MAV Relocating at Vantage Points • Unattended surface sensors from Imagery to Seismic Detection

  39. Urban 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

  40. Biochemical Sensing • Gradient Sensors and Flight Control Feedback to Map Size of Hazardous Clouds • Provide Real Time Tracking Information

  41. MAV 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

  42. MAV 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

  43. Propulsion • 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

  44. MAV Control Guidance Communication • 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

  45. MAV 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

  46. MIT 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

  47. Smart 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

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