Final [Presentation] AIAA_ImprovedSurfaceMarkerBuoyforScubaDivers

DESIGN OF IMPROVED SURFACE MARKER
BUOY (SMB) FOR SCUBA DIVERS
Min Maung, Kevin Sakumoto, Cody Sato, Brandon Uchimura
University of Southern California
Department of Aerospace and Mechanical Engineering
PRESENTERS:
Sunday, March 29th, 2015DATE:

|
BACKGROUND
BACKGROUND >> PROJECT SCOPE >> APPROACH >> DESIGN ITERATION >> FINAL DESIGN
What is a Surface Marker Buoy (SMB)?
• Device used by Scuba Divers
• Inflated and released from submerged
diver at depth, typical max 35 m
• Ascends to surface when inflated
• Signal location of submerged divers to
observers at surface

|
BACKGROUND
How to Use an SMB:
1. Attach SMB to line
attached to a reel
attached to the
diver.
2. Inflate SMB with air
from diver’s dive
tank regulator to
about 50% capacity.
3. Release the SMB
and monitor its
ascent to the
surface.
4. Apply tension to reel
line when the SMB
surfaces to ensure
upright position

|
BACKGROUND
Problems with SMB Currently in
the Market:
1.Reel Jamming

|
BACKGROUND
the Market:
1. Reel Jamming
2. Uncontrolled Ascent

|
BACKGROUND
the Market:
1. Reel Jamming
2. Uncontrolled Ascent
3. Inflation of SMB

|
Design Requirements:
1. SMB can stabilize autonomously at the surface
2. SMB is not submerged more than 40% at the surface
3. SMB vertical ascent velocity is minimized
4. SMB can inflate without pressurized air from diver’s air tank
PROJECT SCOPE
BACKGROUND >> PROJECT SCOPE>> APPROACH >> DESIGN ITERATION >> FINAL DESIGN

Steps for Iterative Method
1. Develop MATLAB model of ascent and stability at surface of SMB
2. Fabricate a functional prototype
3. Test and evaluate the functional prototype
APPROACH
MATLAB MODEL FABRICATION
TEST AND
EVALUATION
Y/N
FINAL PRODUCT
DESIGN

|
CONCEPT:
• 3 passively-controlled
nozzles on opposing sides
of SMB
• 1 excess thrust nozzle at
base of SMB
• Valves release air to keep
vertical trajectory
PRODUCT DESIGN ITERATION #1:
CONCEPTUAL DESIGN
PRESSURE RELIEF
VALVE (x4)
SMB BODY

PHYSICAL MODEL:
Illustration of forces acting on
buoy.
FB = ρwater VSMB g
NUMERICAL SIMULATION
FB

PHYSICAL MODEL:
buoy.
FB = ρwater VSMB g
FD is drag acting on the SMB
and Fg is weight of buoy.
FB
FD
Fg

PHYSICAL MODEL:
buoy.
FB = ρwater VSMB g
FD is drag acting on the SMB and
Fg is weight of buoy.
Fthrust is force created by mass
flow from valves
Fthrust
FB
FD
Fg
Fthrust
Fthrust

PLOT FORCES v. TIME:
Fthrust << 1N at all times.
Not enough mass flow to adjust trajectory.
Fthrust
FB
FD
Fg
Fthrust
Fthrust
FD FB Fthrust
t [s]
F[N]

PLOT FORCES v. TIME:
FD = FB once the buoy reaches terminal velocity, Uterminal
FD FB Fthrust
t [s]
F[N]
Fthrust
FB
FD
Fg
Fthrust
Fthrust

|
CONCEPT:
• Drag chute attached to base
of SMB
• Drag chute fills with water
during ascent to shift CG
CONCEPTUAL DESIGN
PRESSURE RELIEF VALVE
SMB BODY
DRAG CHUTE

NUMERICAL MODEL
Adragchute used for fabrication:
0.092 m2 (1 ft x 1 ft)
PLOT TERMINAL VELOCITY v. AREA OF DRAG CHUTE:
Factors to consider:
• Low terminal velocity to avoid uncontrollable ascent
• Large enough chute area to provide stability at surface
FB
Adragchute [m2]
Uterminal[m/s]
FD
Fg

NUMERICAL MODEL
PLOT CG-CB V. CHUTE HEIGHT
CG: Centroid of an object
CB: Centroid of submerged object
CG
CBhdragchute
hdragchute [m]

NUMERICAL MODEL
PLOT CG-CB V. CHUTE HEIGHT
CG: Centroid of an object
CB: Centroid of submerged object
hdragchute used for
fabrication:
0.125 m (~5 in)
hdragchute
hdragchute [m]
CG
CB

Hollow rods bent around metal
rings
Chute attached with soldering iron and
adhesive
Ring
Rods
Adhesive
PRODUCT DESIGN ITERATION #2A:
FABRICATION

Close up view
Chute
attached
to buoy
FABRICATION

|
FUNCTIONAL TEST METHOD:
Stability During Ascent:
Released buoy and chute from submerged position to
qualitatively test for chute stability
Stability at Surface:
Qualitatively assessed if buoy remained upright at surface
PRODUCT DESIGN ITERATION #2A+B:
TEST AND EVALUATION

|
TEST AND EVALUATION
HEXAGONAL CHUTE:
• Corners/joints broke and were not
rigid enough to keep chute shape
• Chute collapsed during ascent and
at surface

Improvements:
• Rubber bands to
make flexible
joints
• Thicker, solid
rods
• Thicker nylon
fabric
Rubber band
Heat
treatment
Rods
PRODUCT DESIGN ITERATION #2B:
FABRICATION

New additions to design:
• Sewing
• Adhesive
• Zip ties w/rods and hooks
Zip ties
Rods and hooks
Adhesive Sewing

New square chute did not
break apart:
• Rods remained straight
• Joints stayed together
• Chute folds as designed

|
PRODUCT DESIGN ITERATION #2B:
TEST AND EVALUATION
SQUARE CHUTE:
Joint rigidity problem fixed
à Sturdier
BUT…
Joints kept
unbalanced shape
à Chute not
symmetric
NOT STABLE AT
SURFACE

|
SUMMARY OF FUNCTIONAL TESTS:
Joints did not function well enough to justify using design
Fabrication limited the functionality of the design
PRODUCT DESIGN ITERATION #2A+B:
TEST AND EVALUATION

|
CONCEPT:
• Weight hung from bottom of
SMB
• Replicate reel tension for
surface stability
• Added weight reduces
ascent velocity and
trajectory perturbations
CONCEPTUAL DESIGN
PRESSURE RELIEF VALVE
SMB BODY
WEIGHT

NUMERICAL MODEL
0"
5"
10"
15"
20"
25"
30"
35"
40"
45"
50"
0.2" 0.3" 0.4" 0.5" 0.6" 0.7" 0.8" 0.9" 1"
height&submerged&[%]&
mass&of&weight&[kg]&
40%"SUBMERGED"HEIGHT"LIMIT"
PLOT MASS OF WEIGHT, mweight v. SUBMERGED HEIGHT, hsubmerged:
Maximum
allowable mweight
= 0.820 kg
mweight [m]
hsubmerged[m]
hsubmerged

PLOT TIME RESPONSE OF SMB ANGULAR POSITION, θ:
NUMERICAL MODEL
!10$
0$
10$
20$
30$
40$
50$
60$
0$ 0.5$ 1$ 1.5$ 2$ 2.5$ 3$ 3.5$ 4$ 4.5$ 5$
angular'posi,on'[deg]'
,me'[s]'
+θ
θinitial: 60°
mweight: 0.526 kg
t [s]
θ[°]

NUMERICAL MODEL
!10$
0$
10$
20$
30$
40$
50$
60$
0$ 0.5$ 1$ 1.5$ 2$ 2.5$ 3$ 3.5$ 4$ 4.5$ 5$
angular'posi,on'[deg]'
,me'[s]'
PLOT TIME RESPONSE OF SMB ANGULAR POSITION, θ:
θinitial: 60°
mweight: 0.526 kg
+θ
t [s]
θ[°]

Velocity [m/s] PRODUCT DESIGN ITERATION #3:
NUMERICAL MODEL
PLOT TIME RESPONSE OF U
mweight: 0.526kg
Uterminal reached in < 0.1 s.
Uterminal @ tss,2%
t [s]
U [m/s]
FB
FD
Fg
𝑈"#$%&'() =
2 ∗ 𝐹. − 𝐹0
𝜌2("#$ 𝐴4$5666#4"&5' 𝐶8

NUMERICAL MODEL
PLOT TIME RESPONSE OF DEPTH
mweight: 0.526kg
tascent < 9 seconds from a depth of 35 m to surface
t [s]
depth [m]
35 m depth

NUMERICAL SIMULATION: m vs Uvelocity
Uterminal varies by < 1.5 m/s for a weight attachment of 0.5 kg and 1.5 kg
àso sizing is BALANCE among design factors.
àmweight = 0.526kg is a balance
NUMERICAL MODEL
mweight [kg]
Uterminal[m/s]
FB
FD
Fg
𝑈"#$%&'() =
2 ∗ 𝐹. − 𝐹0
𝜌2("#$ 𝐴4$5666#4"&5' 𝐶8

Buoy
Weight
apparatus
Test rig
FABRICATION
Carabiner

Fabrication Method:
• Weight is secured onto test rig
• Test rig connected to carabiner
• Carabiner connected to buoy

|
QUALITATIVE SUMMARY OF FUNCTIONAL TESTS:
During Ascent:
Trajectory perturbations dampened
Added weight to SMB reduced ascent speed
At Surface:
SMB achieves surface stability in both calm and wave
conditions
TEST AND EVALUATION

|
TEST METHOD: for Height Submerged of SMB
Static Testing
Attached various masses to bottom of SMB and measured height
submerged, hsubmerged
TEST AND EVALUATION
SMB
mweight_2
hsubmerged_1
hsubmerged_2
mweight_1

|
RESULTS: for Height Submerged of SMB
TEST AND EVALUATION
0"
5"
10"
15"
20"
25"
30"
35"
40"
45"
50"
0.2" 0.3" 0.4" 0.5" 0.6" 0.7" 0.8" 0.9" 1"
height&submerged&[%]&
mass&of&weight&[kg]&
theore2cal" experimental" limit"
Outliers result from differing
submerged volumes with mass
changes
40% SUBMERGED HEIGHT LIMIT
mweight [m]
hsubmerged[m]
hsubmerged

|
TEST METHOD: for Surface Stability
Dynamic Testing:
Perturbed the buoy at an angle of 60° and determined convergence
to a stable state (0°± 5°).
TEST AND EVALUATION
SMB
θinitial = 60°

!30
!20
!10
0
10
20
30
40
50
60
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
q[°]
t"[s]
theoretical experiment
|
TEST AND EVAULATION: for Surface Stability
TEST AND EVALUATION
Both datasets show
convergence to 0°
tss_th_5deg = 1.9s
tss_exp_5deg = 4.7s +θ
t [s]
θ[°]

|
TEST METHOD: for Ascent Time
Measure ascent time , tascent from a specified depth until top of SMB
reaches surface of water
TEST AND EVALUATION
depth

|
Known Limitations with Testing for Ascent Time:
RESULTS:
Identified time to Uterminal < 1s
Ascent data was not within acceptable uncertainty
àBuoy depth not accurate enough
àInconsistent external forces lengthen distance of ascent
TEST AND EVALUATION
1. Lack of certified
experimental diver to
conduct test at 35 m
depth in a controlled
test setup
2. Limited space
to build on-site
controlled test
setup
3. Swimming pool
depths (3-5 m) not
deep enough

FINAL PRODUCT DESIGN AND
EVALUATION
Capsule
Air Canister
3-View Drawing
units mm

• Have not built/tested yet
• Makes the weight more compact
• Includes air canister and tube to
fill buoy
Tube
Buoy
nozzle
Buoy
Capsule
FINAL PRODUCT DESIGN AND
EVALUATION

REFERENCES |
GENERAL
• Weight apparatus accomplished design criteria:
– Stabilizes at surface when perturbed
– Submerges < 40% of SMB height
– Dampers ascent perturbations and weight apparatus increases FD to reduce Uterminal
– Pressurized air canister does not require diver to use mouth piece to inflate SMB
FUTURE WORK and PROPOSALS
• New controlled test setup
– Long cylindrical column of water, 40m height and x4 SMB diameter, with pulley
motor attached to rope attached to SMB to submerge SMB to testing depth
– Overcomes limitations from strong buoyant forces
• Continue refining final design
– Stress analysis
– Human-‐factor usability tests
CONCLUSION

REFERENCES |
"Satellite Applications for Geoscience Education." Satellite Applications for Geoscience Education.
N.p., n.d. Web. 04 Sept. 2014.
<https://cimss.ssec.wisc.edu/sage/oceanography/lesson4/concepts.html>.
Saltsman, Robert R. "Diver Operated Tools and Applications for Underwater Construction." University
of Florida (1987): n. pag. Web. 4 Sept. 2014. <http://www.dtic.mil/dtic/tr/fulltext/u2/a190264.pdf>.
"Result Filters." National Center for Biotechnology Information. U.S. National Library of Medicine, n.d.
Web. 04 Sept. 2014. <http://www.ncbi.nlm.nih.gov/pubmed/10517789>.
Prusa, Joseph M. "Hydrodynamics of a Water Rocket." SIAM Review 42.4 (2000): 719. Web.
<http://epubs.siam.org/doi/pdf/10.1137/S0036144598348223>.
"XS Scuba Surface Marker Buoy." XS Scuba Surface Marker Buoy. XS Scuba, 2014. Web. 05 Sept.
2014.
REFERENCES
[1]
[2]
[3]
[4]
[5]

REFERENCES |
QUESTIONS?

Y
X
XY
CENTER OF GRAVITY (CG)
CENTER OF BUOYANCY (CB)
Y
X
XY
FW
FH20_1
FH20_2
FEXT
+q
+M
FB
ADRY_2
AH20_1
AH20_2
PH20_1
PH20_2
FH20_1
FH20_2
+q
Y
X
XY
FW
FW cosq
FW sinq
FB
FB sinq
FB cosq

Final [Presentation] AIAA_ImprovedSurfaceMarkerBuoyforScubaDivers

Recommended

Recommended

More Related Content

Similar to Final [Presentation] AIAA_ImprovedSurfaceMarkerBuoyforScubaDivers

Similar to Final [Presentation] AIAA_ImprovedSurfaceMarkerBuoyforScubaDivers (20)

Final [Presentation] AIAA_ImprovedSurfaceMarkerBuoyforScubaDivers