Design of the Life-ring Drone Delivery System
(LDDS) for Rip Current Rescue
Context
Rescue Process
~40% of US adults go to the beach each year.
Stick Figures Graphic
Surf Zone Fatalities 2014 Total
100%
50%
7%
0%
3%
6%
5%
Rip Current Measurements
Shoreline
Neck
Length
Width
~[100,1000] feet
Primary-Drowning
Secondary-Drowning
Speed [1,8] feet/second
Head
USLA, NOAA
http://floridadisaster.org/EMTOOLS/Severe/documents/Rip%20Current%20Brochure.pdf
Drone Integration!
(Our drone system will integrate
with the report in)
There are ways to escape from rip currents.
Float with current, fight against current, swim parallel to shore
Victim drowning is then averted
and victim can be rescued by
lifeguard at their leisure
Secondary-Drowning
Option 2: near guard towers.
Range of the nearest towers.
Closer to shore & eyesight of victims.
Victim, Lifeguard, & Drone
Victim Panics
Set Ω: Design of Drone
Motors
Drone Platform
(quad/hexa/octo)
Battery
Option 3: At Sea
Avoid regulatory problems
Section
Flotation device
alternatives
Victim
3. Boat
Swim to drowning victim
1. Control
Room
2. Tower
Tower
Cost & Utility
u  s S  T TR  E E
Lifecycle Cost (2yrs)
Primary-Drowning
System Acquisition Cost
Drowning Averted
Identify Drowning Victim
Lifeguard secures victim
Report in
Annual Repair Cost
Camera System
Annual Maintenance
Cost
Swim to drowning victim
Tether
Leave home point
Drone flys to victim
Drop flotation device
Operations and Support Cost
Drone Platform
Tether Release System
Victim
Saved
Rip tides are, on average: Annual
beach rescues: 81%, Annual beach
fatalities: 79%, Average annual fatalities: 51
Lifeguards can reach victims in max
of 92 seconds, Some victims have survival
times as low as 60 seconds.
When the report in is received
1. Drone leaves
2. Drone flys to victim location
3. Drone drops flotation device
Primary-Drowning
Range of multiple towers.
Easier to charge drone. Safer for the drone.
With Drone
Feeder
Current
Speed
Length
Victim Panics
Victim Dies
Surf Zone
[10,200] feet
Option 1: main control room.
Victim & Lifeguard
Worst Case scenario!!!
Lifeguard unable to reach victim Victim Panics
in time to enact rescue.
1. LG ID’s drowning victim
Identify Drowning Victim
2. Report in noticing victim
3. Swim to victim
Report in
• Worst case, are unable to
reach victim before death
~80% of rescues & fatalities are caused by rip currents
Width
Set Α: Drone Location
Only Victim
With Lifeguard
Rip Current
High Surf
Sneaker Wave
Other
Unknown
Alternatives
Victim Dies
79%
victim is caught is a rip current
1. Victim Panics
2. They enter PrimaryDrowning
3. Then enter SecondaryDrowning
4. Then die
Andrew Hardy
Mohammed Rajeh
Lahari Venuthurupalli
Gang Xiang
Annual Battery
Recharging Cost
Disposal
Cost
S = % lives saved
TR= mean time to reach
victim
E = mean battery energy
usage per rescue
Controller’s salary
Environment Protection
Equipment
Battery Acquisition
Location Setup
User manual/Training
Model
Inputs (Random)
Rip
Rip
Current Current
Speed Length
…
…
Rip
Current
Width
…
Outputs
Rip Current Victim
Y- Position Escape
Method
…
Repeat above for X reps, until
% Saved σ < 10 %
…
Results: ->
Base Hex
Reach
Time
Conclusions & Future Work
Results
Baseline
Base Octo Octo 2-ring Lifeguard
Reach
Reach
only reach
Time
Time
time
…
…
…
% Saved
% Saved
% Saved
…
Victim
Survival
Time
…
% Saved w/0 drone
Historic
USLA Data
on
Fatalities/
Rescues
Graph
Histogram for various paths
and locations
Vs
time
Graph
Distance from shore vs
Victim position
% Saved
Graph
Design alternatives results
Flotation device selection
TEXT
Text
Recommendations
Inputs for Alternatives Analysis
(1 at a time)
(same reps as before or less reps?)
Location
Battery Type
Motor Types
3 locations
Use battery
equation
Use motor
equations
CATSR(logo)
Outputs (add time to reach as well?)
Base Hex % Saved
Base Octo % Saved
Octo 2-ring
% Saved
Graph
Guarded rescue util
Vs
Cost
And/or
Alternatives avg time to reach
Vs
% saved
Graph
Unguarded rescue util
Vs
Cost
And/or
Alternatives avg time to reach
Vs
% saved
System Engineering & Operations Research, George Mason University ExpertDrones(logo)