PowerPoint Presentation
Week 7 Engineering ReviewOwen Accas - Dan Crossen - Rebecca
Irwin - Madeline Liccione - Hao Shi1Detailed Block Diagram
Energy Flow Graph
Double Stance
Time Propagator (RK 4)Single Stance
aoCurrent Prototype v.s. Proposed System Simulation
ComparisonCurrent Prototype ParametersProposed System
ParametersUnits of ParameterNumber of spokes55QuantityLength of
legs0.40640.41656mMass per spoke0.7370.827KgInertia per
spoke0.0210.0205Kgm2Mass of inertia wheel0.91081.25KgInertia of
inertia wheel0.07230.1161288Kgm2k-value of spring37Nm/rad
10mm diameter aluminumAssume no tension/compression or
insignificant tension/compressionShear modulus = 26 GPaArea =
Pi*(.01m)^2=pi*10^-4 m^2Shear failure at ~204 million Newtonswhich
is approximately 45.8 million lbsThis strength will more than
account for the forces seen on the axle in shearAxle7Worst case: 1
plate rigid, 1 side has full torqueFull torque = (40 lbs/spring)*(2
springs)*1.5 in=120 in-lbsBending force on each brace=(120
in-lbs)/(14 inches)/(5 braces)=1.714 lbs/brace, therefore assume
2.5 lbs with a safety factor
Braces8Shear Strength = 10,500 PSIWith 100 pounds, we would need
a cross sectional area of .00952 in^2 or greater to avoid
failureWith 2.5 lbs (calculated on previous slide), we would see no
failure at all, as the pvc we are using has an area of .256
in^2These will ad .172 kg to entire frame, but add .0217 kg-m^2 of
inertia (about 20% increase)Choosing Braces
Plate Selection (Core)The core material we intend to use is
Core-Cell Foam, a boat building and repair supplyRelatively
inexpensiveVery strongReadily attainableThinLow densityPlate
Selection (Core)Balsa wood is also a popular core material for
composites applicationsDeemed to be more expensiveNot as
strongSimilarly thinHigher density than Core-cell
Plate Selection (Composite)SAE Boeing Carbon fiber is our
selected coatIncredibly strong, especially in tension and
compression (along the weave)Very thinVery consistentAesthetically
pleasingWould be expensive (~34.99 per 50 x 30)We have a free
connection to needed amount
Plate Selection (Composite)Fiberglass was another option for our
top coatLess expensive than carbon, if we had to buyNot quite as
strongMost fiber weaves are more randomSimilar material properties,
carbon is free 2 Gyroscopes (L3GD20) 3.3 V @ 7 mA = .0462 W1
Encoder (E5) 5 V @ 50 mA = .25 WCurrent Sensor (ACS714) .000012 V @
10 mA = ~negligibleMicrocontroller = 0.246mW
Total Power = 0.307WPower Consumption of Electronics14Requested
Specs:
