Mini-Machines

1
Mini-Machines

• Team 9 Members
• Ryan Barnes
• Vincent Chan
• Richard Nip
• Wahib Toulany
• Supervisor
• Dr. Kujath

2
Overview

• Requirements Definition
• Controller Gantry Set-up
• Mini-machines
• Initial Design
• Final Design
• Testing Refinement
• Video
• Budget
• Conclusion Recommendations
• Acknowledgements
• Question Period

3
Requirements Definition

• 4 mini-machines
• Different locomotion for each machine
• 2 DOF
• Volume of 8 cm3
• Simplicity
• Structural stability
• Power

4
Mini-Machines

• Gopher
• uTank
• BoP
• Donatello

5
Controller Gantry Setup

• Preventing wires from touching, causing a
  short-circuit
• Gantry and a controller were built

6
Controller Setup

• Wires were too stiff and heavy
• Thinner wires were introduced
• Thick wires were left at the base of the motor
  because the thinner wires were difficult to
  solder on

7
Gopher Initial Design
8
Gopher Initial Design

• Consists of 2 bodies
• Bodies joined by a bar across the top
• Each body contains a stopping device
• Alternates pivot points
• Produces rotational motion

9
Gopher Initial Design

• Gophers motion

10
Gopher Prototype of Initial Design
11
Gopher Final Design
12
Gopher Testing Refinement

• Gopher design was flipped upside down
• Wires would restrict Gophers movements
• Thinner wires were used
• Wires would tangle and short-circuit
• Elastic bands prevents wires from tangling
• Uses impulse from the motor

13
Gopher Video
14
Gopher Conclusions

• Only achieved 1 DOF
• Simple Design
• Structurally Stable (Withstood 1m fall)
• Less than 8 cm3

15
uTank Initial Design
16
uTank Initial Design

• Originally had tracks too complicated
• Driven by a 1-link system
• Powered by an electric relay
• Produces forward and rotational motion

17
uTank Initial Design

• 1-link system consists of an arm extended from an
  
• electric relay

18
uTank Final Design
19
uTank Final Design
-Consists of a body with 4 wheels -Powered by
two electric motors -Two wheels connected
directly to the motor two wheels move
freely -Wheels have a rubber surface to prevent
slip
20
uTank Final Design
-Motion is produced when the force of the motor
overcomes the frictional force -uTank is capable
of forward and rotational motion -The top, front
and back of the shell were removed making it
easier to access the motor
21
uTank Testing Refinement
-Problems with balancing 4-point
contact -Sometimes the driving wheel would not
contact the ground -Linear and rotational motion
were fine when balancing was not a
factor -Vertical slots were added to the free
moving wheels
22
uTank Testing Refinement
-Driving wheels would always be in contact with
the ground
23
uTank Video
24
uTank Conclusion
-Successful in achieving 2 DOF -Structural
stable Survives 1m fall -Less than 8cm3
-Simple Design
25
BoP Initial Design
26
BoP Initial Design

• Concept is similar to old style computer mouse
• Consists of a base enclosing a ball
• Driven by 2 one-link systems
• Powered by an electric relay
• Capable of forward and rotational motion

27
BoP Final Design
28
BoP Final Design

• Base encloses Ball
• Base consists of 2 rings and a beam
• Driven by 2 electric motors
• New pinion reduces slip on the ball
• Motor force greater than friction force

29
BoP Video
30
BoP Conclusion

• Successful in achieving 2 DOF
• Simple Design
• Structurally Stable survived a 1 m fall
• Volume less than 8 cm3

31
Donatello Initial Design

• Aluminum I-beam body
• 4 Cantilever beams each beam has a leg/
  ratchet component
• Motion is incurred by deflection of beams
• Actuator Shape Memory Alloy Wire (SMA)

32
Donatello

• SMA contracts 3-5 of its original length
• Requires force to return it to original shape
• Maximum Deflection depends on length of SMA
  contraction
• (assuming spring constant of beam is not
  exceeding tension limits of SMA wire)

33
Initial CalculationsDetermining feasible speed

• 20mm wire contracts 0.6 1 mm
• 3 sec per actuation 1 sec contraction 2 sec
  cooling
• Able to achieve 1.2 2 cm/min

34
Initial CalculationsDetermining cantelever beam
dimensions.

• SMA wire able to withstand 3.3 N in tension
• k P/d 3EI/L3 eq. 1
• Ibt3/12 eq. 2
• Aluminum found to have desirable Modulas of
  Elasticity (72 GPa) while remaining elastic under
  0.8 mm deflections
• L, b, t where then determined to fit volume
  criteria while meeting required spring constant.

35
Donatello Testing Refinement

• Test 1 No motion
• Problem SMA not contracting due incomplete
  circuit
• Solution Electrically insulated body with coat
  of epoxy
• Test 2 No motion
• Problem Aluminum legs were plastically deforming
• Solution replaced with stiffer material

36
Donatello Testing Refinement

• Test 3 No motion
• Problem New leg is too stiff, SMA unable to
  contract
• Solution 1 Reduce number of springs in parallel
• Solution 2 Alter position of SMA

37
Donatello Testing Refinement

• Test 4 Leg Motion Achieved
• Problem 1 Displacement in horizontal much
  smaller than intended
• Problem 2 Leg is being lifted vertically
• Problem 3 SMA movement between body and
  electrical wires

38
Donatello Final State of Design
39
Donatello Video_1
40
Donatello Video_2
41
DonatelloConclusion

• Structurally Stable survived a 1 m fall
• Volume less than 8 cm3

42
Budget
Item Quantity Price Sub-Totals
Shapelock 1 20.15 20.15
SMA 1 10.00 10.00
Epoxy 1 7.80 7.80
JB Weld 2 8.00 16.00
Plastic Metal 1 8.50 8.50
Clamps 1 2.00 2.00
Balsa Wood 1 3.75 3.75
Motors 12 2.00 24.00
RC Car 1 7.00 7.00
Aligator Clips 1 4.00 4.00
Wind Up Cars 3 1.50 4.50
Glue 1 5.00 5.00
Solder 1 14.00 14.00
Total     126.70
43
Conclusion Recommendations
Criterion Gopher uTank BoP Donatello
Max Volume of 8cm3 ? ? ? ?
Structural Stability ? ? ? ?
DOF ? ? ? ?
Unique Locomotion ? ? ? ?
Simple Design ? ? ? ?
Controller/Gantry Setup ? ? ? ?
44
Conclusion Recommendations

• 2 of 4 Mini-Machines satisfy all design
  requirements
• Incorporate wireless controllers into the design
• SMA is difficult to implement
• Other methods of locomotion may yield better
  results

45
Acknowledgements

• Shell
• Dr. Kujath
• Greg Jollimore
• Neil Ellerington
• Angus MacPherson
• Peter Jones
• Dr. Hubbard
• Mechanical Engineering Department

46
Questions?