Detailed Design Review Tethered Glider P14462 12/10/2013 14462
Outline • Engineering Requirements • Glider Status • Tether Design • Base Station Design • DAQ System • Bill of Materials • DOE ANOVA Analysis • Test Plan • MSD II Plan • Work Breakdown • Risk Assessment 12/10/2013 14462
Engineering Requirements 12/10/2013 14462
Glider Status • Art’s Plane o Suffered Multiple Crashes o Totalled • 1 st Bixler o Few flights on first day o Missing in swamp • 2 nd Bixler o On order 12/10/2013 14462
1 st Bixler • Learned how to glue glider and set up receiver • Needed to be modified due to poor manufacturing o Drilled out interfering plastic/wood • Bixler was tail heavy 12/10/2013 14462
Tether Design • DynaGlide Throw Line o Material: Dyneema with Vinyl Coating o Vendor: WesSpur o Diameter: 1.8mm o Tensile Strength: 1000 lb o Highly Visible o Price: $39.00 for 200 feet 12/10/2013 14462 http://www.wesspur.com/throw-line/zing-it-throw-line.html
Tether Drag • Numerical Approximation • Calculates: o Tether Drag o Tension Change o Tether Angle Change Rajani, Ashok, Rajkumar Pant, and K. Sudhakar. "Dynamic Stability Analysis of a Tethered Aerostat." Journal of Aircraft 47.5 (2010): 1531-538. American Institute of Aeronautics and Astronautics . Web. 7 Dec. 2013. <http://arc.aiaa.org/doi/pdf/10.2514/1.47010>. 12/10/2013 14462
Tether Drag Total tether drag of DynaGlide tether: 27.063 N Negligible force compared to the lift and drag 12/10/2013 14462
Tether-Wing Attachment Setup 12/10/2013 14462
Tether-Wing Attachment • Tether may rip EPO foam if attached directly • Design plate to rest on top of wing o Distributes load o Foam is minimally damaged • Tethered over carbon fiber spars • Material: Polycarbonate 12/10/2013 14462
Tether-Wing Attachment Setup 12/10/2013 14462
Tether-Wing Attachment Stress Analysis Plate material: Polycarbonate Max stress: 38.4 GPa Max allowable: 55 GPa 12/10/2013 14462
Tether-Wing Attachment Displacement Analysis Plate material: Polycarbonate Max deflection: 0.002 in 12/10/2013 14462
Bridle Setup • 3 point bridle with extra support line • Use crimps for permanent attachments • Adjustable fuselage tether to change bridle angle 12/10/2013 14462
Bridle Setup 12/10/2013 14462
Base Station - Week 6 Concept ● Concept from week 6, selected by week 9 ● Consists of 2 potentiometers and 1 load cell 12/10/2013 14462
Base Station - Detailed Design 12/10/2013 14462
Base Station - Detailed Design 12/10/2013 14462
Exploded View of Upper Portion 12/10/2013 14462
Design Focus - Upper Portion • Wanted minimal flexing on the shaft in order to prevent bearing seizure • Wanted to prevent screw pullout • Wanted minimal plywood flexing • Ensure top bolt did not tear through plywood due to loading 12/10/2013 14462
Shaft Selection y T=1200 lbf x R L =600 lbf R R =600 lbf ● Wanted to minimize deflection, bending stress, and moment of inertia of shaft ● Utilized Excel and varied L and R and calculated corresponding deflections and max stress 12/10/2013 14462
Shaft Selection Continued Selection: ¾” x 7’’ AISI 1566 Steel shaft ● Only 4” of the shaft will be between the bearings, which is the length used for deflection and stress calculations. ● With these values the shaft will deflect 0.0036” under the max loading of 1200 lbs ● The thicker shaft allows for tapping in order to connect the load cell 12/10/2013 14462
Pillow Block Screw Pullout y T=300 lbf x Selection: 4 #12-10 machine screws ¾” C-D grade plywood http://www.grabberman.eu/Me dia/TechnicalData/452.pdf 12/10/2013 14462
Plywood Flexing ● Modeled as an isotropic material, although wood is anisotropic ● Showed max deflection of 0.503E-05 inches 12/10/2013 14462
Bolt Tear Through ● Wanted to prevent the bolt 1200 lbf from tearing through the plywood ● A 3 inch washer was added 8692 psi to distribute the loading on the face of the plywood 1200 lbf Without Washer: Compressive stress on the plywood of 8692 psi. The maximum allowable compressive stress for loading perpendicular to the face grain is between ~ 900 – 1500 psi 170 psi With Washer: Compressive stress on plywood of 170 psi, within the allowable stress Source: www.buildgp.com/DocumentViewer.aspx?repository=bp&elementid 12/10/2013 14462
Pillow Block Bearings ● Shaft will insert and then be screwed down with set screws ● Do not need to be thrust bearings, as platform will rotate Selection: ¾” Stamped-Steel Mounted Ball Bearings — ABEC-1 12/10/2013 14462
Exploded View of Lower Portion 12/10/2013 14462
Design Focus - Lower Portion • Wanted to ensure sleeve bearing did not deform under worst-case scenario loading • Wanted to prevent screw pullout • Ensure sheet metal flexed minimally under applied load 12/10/2013 14462
Sleeve Bearing T=1200 lbf H R h s R R b ● Utilized Excel to calculate various reaction L forces for different h sb , and compared versus the max allowable force on the inner walls of the bearing ● For worst case scenario chosen bearing will see 5100 lbs and it is capable of handling 6016 lbs. Selection: 0.752” x 1” Ultra Tough Oil Lubricated Bronze Flanged Sleeve Bearing 12/10/2013 14462
Angle Iron Pullout and Shear F=300 lbf Selection: F=200 lbf 1”x1”x1/8” angle iron with #12 screws F=300 lbf 6 vertical screws, and 4 horizontal ¾” C -D grade plywood http://www.grabberman.eu/Me dia/TechnicalData/452.pdf 12/10/2013 14462
Sheet Metal Plate • Max deflection of ~ 0.003 inches
Base Station – Cross Section View 12/10/2013 14462
Base Station Animation Base Station Animation 12/10/2013 14462
NI USB-6210 16 bit Resolution = 10/(2^16) = 0.000153 12/10/2013 14462
3140_0 S Type Load Cell (100-500kg) 12/10/2013 14462
1046_0 PhidgetBridge 4-Input Resolution = 5/(2^24) = 0.000000298 12/10/2013 14462
Potentiometers • 2 pots required. • 1 turn ~ 270 degrees • Between 1K-10K Resistance • Linear • Bourns brand • Potentiometers from Gomes still need to be spec out 12/10/2013 14462
DAQ Operational Flowchart
DAQ Programming Flowchart
Wiring Schematic for DAQ 12/10/2013 14462
Bill of Materials - Full
Bill of Materials – Already Have
Bill of Materials – Need to Buy
Bill of Materials - Possible Savings
Glider Configuration for Experiments Total configurations: 2590 Filtered: Range: Force = 300-350 [lbs] Beta = 90-98 [deg] Wind Speed = 7 [m/s] Wind Speed = 4-10 [m/s] Tether Length = 30 [m] Tether Length = 20-30 [m] Flight Radius = 10-18 [m] Force [lbs] Wind Speed Radius Beta Tether Length [m/s] [m] [deg] [m] 334.3693 7 15 92 30 309.5235 7 16 92 30 349.0444 7 18 93 30 12/10/2013 14462
Regression Analysis including Wind Force = -1523.83 + 44.6977 WindSpeed - 22.0839 Radius + 16.3528 Beta +11.4661 TethLen Analysis of Variance Source DF Seq SS F P Regression 4 14445969 580.40 0 WindSpeed 1 6413421 2006.60 0 Radius 1 2623543 887.44 0 Beta 1 2732563 524.19 0 TethLen 1 2676441 430.13 0 Error 2583 16072377 Total 2587 30518346 12/10/2013 14462
Why the high error ? Residual Plots for Force Normal Probability Plot Versus Fits 99.99 200 99 90 Percent Residual 0 50 10 -200 1 0.01 -400 -200 0 200 100 200 300 400 500 Residual Fitted Value Histogram Versus Order 160 200 120 Frequency Residual 0 80 -200 40 0 -280 -210 -140 -70 0 70 140 1 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 Residual Observation Order 12/10/2013 14462
DOE ANOVA Analysis Analysis is based off of above equation Experiment was run using the following Factor Type Levels Values Radius fixed 9 10, 11, 12, 13, 14, 15, 16, 17, 18 Beta fixed 8 91, 92, 93, 94, 95, 96, 97, 98 TethLen fixed 11 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 Analysis of Variance for Force for Tests Source Seq SS Radius 1074979 Beta 1039829 TethLen 772033 Radius*Beta 383755 Radius*TethLen 263954 Beta*TethLen 312236 Radius*Beta*TethLen 818325 Error 25853236 Total 30518346 12/10/2013 14462
Interaction plots for Tension 12/10/2013 14462
Main effects on tension 12/10/2013 14462
Graphical Sensitivity (contour plots) of each factor 12/10/2013 14462
Graphical Surface plots 12/10/2013 14462
Test Plan 12/10/2013 14462
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