Design of the Life-ring Drone Delivery System for Rip Current Rescue Andrew Hardy, Mohammed Rajeh, Lahari Venuthurupalli, Gang Xiang Tether Hold/Release System Life-ring/Ring-buoy Dji.com, (Schenkel, 2014), Parks.ca.gov, 2015, NOAA Solution 60 93 Victim survival time limit Lifeguard Reach Time Time (s)
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Design of the Life-ring Drone Delivery System for Rip Current Rescue · 2015-12-15 · Design of the Life-ring Drone Delivery System for Rip Current Rescue Andrew Hardy, Mohammed
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• Sarah Litowich, an aquatic director of the Aquatic Fitness Center at George Mason
• Captain Butch Arbin III, Ocean City beach patrol officer in Maryland
• Captain Barry Kirschner, Virginia Beach Dep. of EMS emergency medical technician-enhanced
• Dane Underwood, Red Cross and Ellis and Associates certified instructor
Beach Goers
• Want least restrictions
• Want lifeguards to be 100% effective at their jobs
Manufactures
• Produce equipment to lifeguards who pay the manufactures money
• Ex: Swimoutlet, Marine Rescue Products, USLA
Municipalities
• Beach owners have to warn non-trespassers about dangerous conditions on their property
• States own land seaward of the high tide line
1.
2.
3.
4.
5.
12
Tensions
Beach Goers
Municipalities (Beach Owner)
Life guarding associations
(Certification company)
Equipment Manufactures
Lifeguards
Municipalities (Beach Operator)
Feedback Loops
LG protection/ rescue services
Accident/Injury Liability
Provide revenue Provide clean beaches
13
Liability
Beach Goers
Municipalities (Beach Owner)
Lifeguards
Municipalities (Beach Operator)
Accident/Injury Liability
Provide revenue Provide clean beaches
Beach owner is liable for beach goers
Beach owner is protected under the catastrophic
umbrella insurance for huge damage
Beaches are kept clean by the revenue BG
generate
LG protection/ rescue services
14
Certification
Municipalities (Beach Owner)
Life guarding associations
(Certification company)
Lifeguards
Municipalities (Beach Operator)
LG Associations train professional
LGs
Beach operator documents yearly
certification and training of LGs
15
Feedback for Manufacturers
Life guarding associations
(Certification company)
Equipment Manufactures
Lifeguards
Municipalities (Beach Operator)
Feedback Loops
LG associations, Beach operator
and LGs provide feedback of
equipment manufactures produce
16
Win-Win
Lifeguarding
Operators • Reduce legal actions and save lives.
Lifeguards • Improve rescue process and save lives.
Beach Goers • Increase safety of beaches without added regulation
• Decrease rip current-related deaths
Manufactures
• Allow system to use any life ring/ lifesaving device
• Let beaches use the devices they want within a
certain weight limit (no switching manufacturers)
Municipalities • Increased safety leads to more beach goers, which
lead to more beach services used
No stakeholder is against this Life-Ring Drone Delivery System
17
1. Context
2. Stakeholders
3. Problem/Need Statement 4. Requirements
5. Con-Ops
6. Alternatives
7. Method of Analysis
8. Management
9. Thanks
Problem/Need
Problem Statement
Rip tides are, on average:
• Annual beach rescues: 81% (USLA,2014)
• Annual beach fatalities: 79% (NOAA,2014)
• Average annual fatalities: 51 (NOAA,2015)
Lifeguards can reach victims in a max time of 92 seconds (Butch,2015)
• Some victims have survival times as low as 60 seconds.
Need Statement
There is a need for a system that can reach and assist a victim in under 60 seconds (while
the victim are still an active drowner) in order to increase the victim's survival time.
By decreasing flotation device delivery time, we can reduce drowning deaths by X%.(TBD)
19
System Scope
Design a rescue drone delivery system • Reach victims using camera systems
• Drop flotation device using 1st tether release
• When victim grabs lifesaving device, 2nd tether release drops the lifesaving device and tether, allowing drone to return home.
Determine the best possible design to: • Motor
• Drone Platform (quad/hexa/octo)
• Battery
• Flotation Device
Design a tether holding/releasing system
Tether Hold/Release System
Tethered Lifesaving Device
Front and Down Cameras
In the end, deliver:
1. Drone System Design
1. Business model and Cost Model
2. Rescue System Design
1. Draft training methods and user manual 20
1. Context
2. Stakeholders
3. Problem/Need Statements
4. Requirements 5. Con-Ops
6. Alternatives
7. Method of Analysis
8. Management
9. Thanks
Mission Requirement
MR.1 The system shall reduce the
average annual number of rip current
deaths by a minimum of X%.
22
Functional Requirements
F.1 The system shall hover at a minimum altitude of 3m above the ground.
F.1.1 The system shall hover at an altitude of 3m with a minimum payload of 2.268kg.
F.2 The system shall be operable within X m of the home point.
F.3 The system shall reach a victim within X seconds.
F.3.1 The system shall increase the victim survival time by an average of X seconds, if the
system does reach the victim.
F.4 The system shall be able to restock its payload within X seconds.
F.5 The system shall be able to deploy its payload within X seconds.
F.6 The system shall do the entire rescue process at a maximum time of X seconds.
F.7 The system shall be able to hover within a horizontal distance of 0.5m from the target.
23
Design Requirements
DR.1 The system shall attach the lifesaving device to the drone through a tether.
DR.1.1 The system may have a disconnect method to cut or release the tether in order to deliver the
lifesaving device.
DR.1.2 The system shall have a tether release system that weighs under X kg.
DR.1.3 The system shall be able to release the tether within X seconds of the request to release.
DR.2 The system shall have a camera system pointing downward.
DR.3 The system shall have a camera system pointing forward.
24
Ilities Requirements
Usability
U.1 The system shall be usable by a person that has less than 12 hours of training.
Availability
A.1 The system shall be available to at least any beach on U.S territory
A.1.1 The system shall comply with all federal drone regulations.
A.2 The system shall be available for rescues over 95% of the time.
A.3 The system shall be usable in X rescues a day when balanced charged.
A.4 The system shall have a minimum lifetime of 5 years
Reliability
RE.1 The system will have MTBF of X months
RE.2 The system shall have a tether system error MTBF of 7 days
Resistability
RS.1 The system shall resist sand conditions of an average beach.
RS.2 The system shall resist humiditity conditions of an average beach.
RS.3 The system shall resist temperature conditions.of an average beach.
25
FAA UAS Regulations
Current Advisories UAS flight altitude below 400 ft.
UAS weighs under 55 lbs.
Maintain visual line of sight of the UAS • Spotter allowed
– Minimum 1 spotter per UAS
UAS operator must have a pilot's license
UAS may not be operated in restricted airspace • (grey area)
• not applicable to government
UAS may not be operated for commercial purposes
No Overhead Operation !!!
Proposed Regulations
UAS flight altitude below 500 ft.
UAS weighs under 55 lbs.
UAS may not exceed 100 mph
Maintain visual line of sight of the UAS
• Spotter allowed
– Minimum 1 spotter per UAS
UAS operator:
• Be licensed
• Report incidents in less than 10 days
• Make UAS available for inspection
3 mile visibility from control station
Inspect UAS prior to flight
No Overhead Operation !!! Source: http://www.faa.gov/uas/
26
1. Context
2. Stakeholders
3. Problem/Need Statements
4. Requirements
5. Con-Ops 6. Alternatives
7. Method of Analysis
8. Management
9. Thanks
Rescuing Process with Drone
28 (Butch,2015)
Control Rm
receives
Coordinates Drone
leaves
home point
Drops
tether w/
ring buoy Victim grabs
buoy, tether
is released Drone
returns to
home point
Drone
travels to
victim
LG swims to drowning victim
LG Rescues
LG Guides victim to shoreline
Victim out
of water
Identify
victim Radio
Contr
ol Rm
max 20 s
max 30 s
max 90 s
max 2
s
max 10 s
LG keeps an
eye on Rip
Currents
Emergency
Care
Provided
NO
YES
max 90 s
Stage
1
Stage 2
Con-Ops
Precondition: Lifeguard has identified a drowning victim. Lifeguard is prepared for rescue process. Lifeguard radios control room of the section # or victim’s
general direction. Victim is located somewhere on the rip current and is attempting an escape method. Drone is ready to deploy. Flotation device is stocked
on drone.
Primary: Stage 1
Controller is informed by lifeguard of general area of the victim
Controller takes off drone • Confirm victim location by eyesight if near tower
The system takes off to a height of X meters.
The system accelerates to X m/s towards the section given.
Controller confirms specific location in that section through camera or eyesight. • Relative to Drone
The system maintains X m/s towards the victim's location.
Once the system is within X m of the victim’s location, system shall decelerate to victim’s speed and position. At the same time, the system will reduce
height until the flotation device is just above the water (confirmed by controller).
Primary: Stage 2
The system drops the flotation device and positions it by the victim
Once the victim is about to grab the the flotaton device, system detaches the tether.
The system maintains a X m hover over victim until lifeguard has reached the victim. • Controller uses camera to visually determine victim state (active or passive)
• If necessary Controller inform medical personnel of victim status
Primary: Return
Once lifeguard has reached the victim, or drone has been determined to be of no further use, or drone has reached critical battery charge, system will
be flown back to the home point.
System lands on home point.
Post-Condition: Lifeguard is enacting the rest of rescue process starting with rescuing the victim. Drone has landed back at the home point and awaits
restocking of ring buoy. Victim is being helped by the lifeguard.
29
Identify
•Prepared for rescue
•Identify Victim
•Radio control room
•Flotation device stocked
•Prepared to deploy
•attempting escape method
Beach
Area
Shore
line
30
•Lifeguard swims to drowning victim.
•Leaves homepoint
•Travels to victim
Stage 1
Beach
Area
Shore
line
31
•swims to drowning victim.
•Drops tether with ring buoy
•Releases tether when victim grabs ring buoy
•Victim grabs flotation device
Stage 2
Beach
Area
Shore
line
32
Return
•Lifeguard continues rescue process
•Drone returns to homepoint
•Drone is ready to be resupplied
Beach
Area
Shore
line
33
1. Context
2. Stakeholders
3. Problem/Need Statements
4. Requirements
5. Con-Ops
6. Alternatives 7. Method of Analysis
8. Management
9. Thanks
Design
Alternatives
Set A
• Location of drone station
Set B
• Design of drone
Set C
• Choice of flotation device
Design of Experiment
DoE A
• Location of drone station (TBD)
DoE B
• Design of drone (TBD)
35
Set A: Drone Location
Option 1: main control room. • Operation range of multiple
lifeguard towers.
• Easier to charge drone. Safer for the drone.
Option 2: near guard towers. • Operation range of the nearest
lifeguard towers.
• Closer to shore and allows eyesight to confirm victims.
Option 3: At Sea • Avoid Regulatory problems
Section
2. Tower
Victim
Tower
1.
Control
Room
3. Boat
36
Set B: Design of Drone
Motors
Drone Platform (quad/hexa/octo)
Battery
37
Set C: Flotation Device
Flotation
Device Cost Weight Dimensions Buoyance
Effectiveness
(5 Star)
Usability
(5 Star)
Ring Buoy
(Jimbuoy
JBW-20)
$85.98 3 lbs. 20 in 16.5 lbs. 5 5
Rescue Can
(Jimbuoy
model 8t)
$139.99 4 lbs. 29.5x9.5 in 18.2 lbs. 2 2
Lifejacket
(First Mate –
Stearns
flotation)
$74.99 1.5 lbs. 24x12x3 in 15.5 lbs. 4 4
Ultra 3000
(Auto
inflating life
jacket)
$204.99 3 lbs. 30x52 in 37.7 lbs. 3 3
38
Set C: Floatation Device AHP Analysis
Buoyance
Time of
Delivery Effectiveness Usability Dimensions
Buoyance 1 1/2 5 5 5
Time of
Delivery 2 1 7 7 7
Effectiveness 1/5 1/7 1 1/2 1
Usability 1/5 1/7 2 1 3
Dimensions 1/5 1/7 1 1/3 1
• Comparing 5 factors
• AHP Analysis to find
the best alternative
• Found weights of
each factor
• Still need to
calculate the best
alternative by using
weights
39
• Time of Delivery & Buoyance most important
• Highest rated
• Used Intensity of importance scale to rate others
1. Context
2. Stakeholders
3. Problem/Need Statements
4. Requirements
5. Con-Ops
6. Alternatives
7. Method of Analysis 8. Management
9. Thanks
Drone Info
•Quadcopter = 4 rotors
•Hexacopter = 6 rotors
•Octocopter = 8 rotors
•Opposite rotors have same spin. •2 rotors rotate counterclockwise
•the other 2 rotate clockwise
•This allows drone body to choose to rotate, or not rotate,
depending on the rotational velocity of the rotors.
•Picture on left shows clockwise spin being stronger, thus the
drone rotates counterclockwise.
Stronger clockwise motors =
Body rotates counterclockwise
41
Orientation
Positive x-axis = front side (direction of motor 2)
Positive y-axis = left side (direction of motor 3)
Positive z-axis = top side
Body frame = body reference = drone reference
Inertial Frame = our reference = our point of view
Controller
X
Y
Inertia Frame
Body Frame
42
Axis's of Rotation (Euler Angles) Roll, Yaw, Pitch
EPA, National List of Beaches, 2015. [Online]. Available: http://ofmpub.epa.gov/apex/beacon2/f?p=117:12:6598228724511::NO::P12_YEARS:Current. [Accessed: 14- Nov - 2015].
American Shore and Beach Preservation Association, New study shows beaches are a key driver of U.S. economy, 2014. [Online]. Available: http://www.asbpa.org/news/Beach_News/080814Houston.pdf. [Accessed: 14- Nov - 2015].
Ocean City Maryland, Town of Ocean City Adopted budget, 2015. [Online]. Available: http://oceancitymd.gov/City_Manager/BudgetBook.pdf. [Accessed: 14- Nov - 2015].
USLA, 'Primary Cause of Rescue at Surf Beaches', 2015. [Online]. Available: http://arc.usla.org/Statistics/Primary-Cause-Analysis.pdf. [Accessed: 18- Oct- 2015].
s = length of rope between lowest point and the end (NOT total length)
Equation 1: general form of catenary line
Equation 2: definition of a
Equation 3: definition of λ (helpful variable, no meaning)
Equation 4: A identity used to calculate T0
George Mason University LALVDS Project Team Briefing 4
/.2
)/cosh(*)(.1
0Ta
axaxf
sT
LdS
TL
*.5
/)(/).(sinh4
)2/(.3
1
222
0
100
Removing Homepoint Tether from Simulation?
On Amazon, a 5mm assessory cord over 100m (~300ft) is 1.84kg. • 7mm assessory cord over 100m is 3.02kg.
• 8.8mm hiking cord over 100m is 4.82kg.
• 9mm climbing rope over 100m is 6.3kg.
100m = 328ft (rip currents can be hundreds of feet)
Hexacopter max lift = 5kg • Octocopter max lift = 9kg
Conclusion: A drone lifting a tether from the homepoint to the drone is under heavy weight. Possibly unable to deliver a life ring. • Simulation results soon…