asme mars rocks
TRANSCRIPT
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unc Charlotteunc CharlotteAsme Design TeamAsme Design Team
2008-20092008-2009
Members:Rodger Adams
Philip BrownJohn Cillie
Dory LoBeanAndrew Misenheimer
Dylan Sylvester
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Mars Rocks! Design and build a vehicle that will:
Retrieve rocks and bring them to a designated spotReturn to its starting location and be ready for another runBe able to surmount small obstacles while travelling to the
rocks and carrying the rocks back
Figure 1. Mars Rover2
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Course Description I Flat, level section of any floor type
Marked off with masking tapeCourse size is 2290mm x 3660mmThree barriers–either two 2x4’s on the side or one
4x4
Figure 2. Course Layout 3
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Course Description II
Parking area will be 300x610mm Receiving area will be three concentric
circles ranging from 50mm to 200mm in 75mm increments
Figure 2. Course Layout 4
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Rock Locations Rocks will be approximately placed as
indicated by the circles below
Figure 2. Course Layout
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Rock Description Must range in size of up to
40mm across the widest dimension and at least 20mm in the other dimension
Must weigh between 10 to 80 grams
Must be irregular in shape Must not roll more than one-
half of a rotation when placed on a flat surface Figure 3. Rocky Surface
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Vehicle Requirements Dimensional and Electrical Constraints
Vehicle must have a master ON/OFF switchVehicle and controller must fit within a constraining box of
370mm x 165mm x 165mmVehicle must be powered with over the counter
rechargeable batteriesThe device must be controlled either through a
transmitter/receiver radio link or through an umbilical cordAn umbilical cord controller may not contain any batteries
while a transmitter may contain its own batteriesThe transmitter/receiver radio link may be any
commercially available model controller
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Design Concept I
Figure 5. UGV (Unmanned Ground Vehicle) MATILDA
Figure 4. British Mark V, WWI Tank
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Design Concept II
Figure 6. Proposed 2008-2009 UNC-Charlotte ASME Mars Rocks! Rover. Designed in Pro/Engineer Wildfire 4.0
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Drive train Tank style tread Climbing tread
extension 2 motors, planetary
gearbox with 60:1 final drive ratio
RP plastic and aluminum composite frame
Figure 7. Bottom View of Drive Train Assembly
Figure 8. Exploded View of Drive Train Assembly10
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Gripping Mechanism Gripping:
Servo driven dual arm gripping mechanism
Lifting:Second Servo driven
flipping mechanism Rubberized spherical
cups for friction lifting
Figure 9. Top View of Gripping Mechanism
Figure 10. Side View of Lifting Mechanism 11
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Storage System Inclined rock receptacle
Assists in depositing of rocks
Swinging entry-safety gatePrevents backflow of stored
rocks Servo driven exit gate Houses power supply and
micro servo 40.6 cubic inches
Figure 11. Inclined Rock Receptacle with Swinging Gate Opened
Figure 12. Inclined Rock Receptacle ShowingPower Supply and Servo Placement 1
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Electrical System I 6 channel digital Proportional
72MHz aircraft transmitter 4 Axis, 6 Button Controller Adjustable servo travel Adjustable servo speed Programmable mixing for
drive train control Battery: 11.1V Lithium
Polymer
Figure 13. Hitec Optic 6 Transmitter
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Electrical System II
2 channels used for independent throttle and steering control via 2 ESC’sElectronic mixing programmed within the
transmitter will allow both independent and non-independent control of treads off of 2 axis joystick
1 ch. for servo operated trap door 1 ch. for up/down movement of gripper 1 ch. for open/close of gripper
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Proposed BudgetTable 1. Proposed Budget
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Continuing Concerns
Capacity of batteryWill be determined by scoring formula and trial
and error analysis upon completion of robot Backup Components Material Properties within ProE for safety
factor calculationsIntuitively designed along with supporting
calculations
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Questions, Comments, Input
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Appendix I-Calculations
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Gripping and Lifting System Critical InformationServo Motor Torque 2 in-lbf
Servo Motor Speed4.55 rad/s
Estimated Cycle time 1.5 sRock Gripping Force 0.6 lbfCoefficient of Friction for gripping with safety factor of 2.5 0.7Safety factor for gripping stress on the arm 3.88Safety factor for lifting stress on the arm 6.65
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Appendix II
Servos:Eflite S75 Sub-Micro Servo-Trap
Door○ Torque: 17.2 oz-in. @ 4.8V○ Speed: 0.12sec/60˚ @ 4.8V
Futaba S3003 Std. Servo-Gripper and Flipping Mechanisms○ Torque: 44.0 oz-in. @ 4.8V○ Speed: 0.23sec/60˚ @ 4.8V
Figure 14. Eflite S75 Micro Servo
Figure 15. Futaba S3003 Standard Servo19
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Appendix III Motor and Gearbox:
Table 2. ML-30 Motor Information, 30:1 Reduction
Figure 16. ML-30 Motor with Planetary Gearbox
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Appendix IV
PC-ABS41 MPa Tensile StrengthSG 1.2High Impact Resistance
Al 6061 T6430 MPa Tensile Strength72 GPa Elastic Modulus
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