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ppt on pneumo
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FLUID POWER!
SEE SPLASH 2008
FOLDER
TODAY
• Learn some fluid power basics
• Hands-on project with pneumatic components
• Some possibilities for your FIRST robot
What is fluid power?
• Uses:• Heavy equipment
• Construction industry
• Off-road vehicles
• Manufacturing
WHY FLUID POWER?
STRONG!
LIGHT!
EASY!
CCEFP
Fluid Power is Unique Unparalleled torque, power and bandwidth for the same weight or volume.
Example: Power/Weight (kW/kg)
Pneumatic Motor 0.3-0.4
Hydraulic Motor 0.5-1.0
Electric Motor 0.03-0.1
Fluid power weight advantage = 10:1
Reference: I. L. Krivts and G. V. Krejnin, Pneumatic Actuating Systems for Automatic Equipment, Taylor and Francis, 2006.
CCEFP
CENTER FOR COMPACT AND EFFICIENT FLUID POWER
•100 mpg automobile•Efficient off-road equipment•Compact and portable
CCEFP
CCEFP testbeds
Existing FP applications
FP enabledbreakthroughs
in transportation
New industries & applications
TB1: Excavator TB2*: Injection molding machine
TB3: small UrbanVehicle (sUV)
TB4: Compact Rescue Crawler
TB5*: FP assistedhand tools
TB6: FP assistedorthoses & prostheses
* Reduced or delayed funding
HIGH COUNTRY TEK
Member of the Schaeffler Group
National Tube Supply Company
Ralph Rivera
Master Pneumatic
Pneumatics compared to hydraulics
• No problems of a spills• Compressibility stores energy
– Available for your use– Dangerous if excessive
volumes or pressures
• Difficult to control precisely• Fluid is readily available
– Should be filtered, dry
• Usually lower forces
Safety Must AlwaysBe Considered!
Pressure of an “ideal” Gas
• Pressure of a gas is due to the force of gas molecules bouncing off the walls.
• Pressure increases when molecules are moving faster, heavier, or if there are more molecules.
• Molecules move faster when they are hot.
• mR depends on molecule.
Pressure P
P V mR T
Getting Work out of Air
• Work is force acting over a distance, ft-lbs.
• Put air in a container under pressure
• Allow part of the container to expand
• The expanding part does work
How much energy is in a tank filled with compressed air?
Assume constant temperature:
P = pressure in tank (absolute)
V = volume of tank
Patm= atmospheric pressure = 101,325 Pa or 14.7 psi
constant mRTPV
)/ln( E atmPPPV
Energy:
How much energy is in a small air tank?
• Tank Volume = 150 ml or 9.154 in3
• Pressure = 413,700 Pa or 60 psi (over Patm)
• Patm = 101,325 Pa or 14.7 psi
Answer:
Energy = PV ln(P/Patm) = 0.15 x 515025 x ln(74.7/14.7) = 125 kJ
Challenge question: How high could the instructor be lifted using the energy in one tank?
How much energy in your tankcan you use?
• Line losses:Pressure drop proportional to flow
• Throttling losses:Pressure drop proportional to flow squared
• Cylinder friction:Coulomb plus viscous friction, depends on seals
Force available• Pressure x Area = Force
• Area = pi x Bore2 / 4
• For example cylinder:– Bore = 10 mm = .394 in. Area = .122 in2
– Force = PxA = 60 psi x .122 in2 = 7 lbs
Pressure P Area AP
Force F
CYLINDER FORCE AT 60 PSI
0
100
200
300
400
500
600
700
800
0 1 2 3 4 5
BORE (IN.)
fOR
CE
(L
BS
)
The Effect of Different Areas
Pressure P
Pressure P
Area APArea AR
Force FHow much force F is necessary to hold the rod still?
Pressure Patmosphere
Pneumatic components seen in the FIRST Robotics competition
LET'S BUILD!