1
00:00:00,100 --> 00:03:15,100
[Transcription is missing for 3 mins,
apologies for the delay]

2
00:03:15,500 --> 00:03:15,700
 

3
00:03:15,700 --> 00:03:19,600
So, you know, how do you design an underwater
glider? You have to learn how to

4
00:03:19,600 --> 00:03:22,300
design an underwater glider so it was really
the start of an education, you know, self‑taught

5
00:03:22,370 --> 00:03:29,370
in design and manufacture of underwater vehicles.
So was studying machine tool technology at

6
00:03:31,519 --> 00:03:37,079
the time, manufacturing, engineering type
stuff, eventually got a transfer degree so,

7
00:03:37,079 --> 00:03:43,829
yeah, it was a great vehicle to actually learn
and gave a really good incentive to study

8
00:03:43,829 --> 00:03:49,540
stem subject matter and ultimately transitioned
into an interest in an engineering transfer

9
00:03:49,540 --> 00:03:56,540
degree.
What is an underwater glider. Normal vehicles

10
00:03:56,609 --> 00:04:03,609
glide themselves through the water using a
propeller, pretty straightforward. There's

11
00:04:03,889 --> 00:04:09,339
no propeller in an underwater glider generally
speaking. They use something similar to a

12
00:04:09,339 --> 00:04:15,809
fish's swim bladder in the water and as they
float to the service they have wings on them.

13
00:04:15,809 --> 00:04:19,340
Does this thing work?
 Apparently not.

14
00:04:19,340 --> 00:04:26,340
 So wings? And those actually help transfer
the change in altitude into forward movement

15
00:04:28,039 --> 00:04:33,930
and so the efficiency of the vehicle is going
to be determined by a couple things. First

16
00:04:33,930 --> 00:04:40,930
of all, the efficiency of your fish bladder
the engine, the big factor is the drag, and

17
00:04:42,460 --> 00:04:47,169
also kind of related to drag is your glider
ratio, how many feet forward you move through

18
00:04:47,169 --> 00:04:52,770
the water for every foot you lose or gain
in altitude. One interesting thing in underwater

19
00:04:52,770 --> 00:04:59,770
vehicles is they spend half the time flying
upside down because your gravity vector flips

20
00:04:59,819 --> 00:05:06,819
its head when you are going against the water
column or going down with it so, yeah, they're

21
00:05:10,949 --> 00:05:17,419
autonomous underwater vehicles that can travel
long distances on battery power.

22
00:05:17,419 --> 00:05:21,840
So history, you know, it all started back
in, you know, '80s or something, I wasn't

23
00:05:21,840 --> 00:05:27,879
really born yet so it don't really matter,
very ego sent trick view of the universe so

24
00:05:27,879 --> 00:05:33,020
they had these things called argue goes floats,
they were essentially a coffee can with a

25
00:05:33,020 --> 00:05:38,419
linear motor powered syringe and go through
the water column and collect sensory data

26
00:05:38,419 --> 00:05:43,610
and when they had enough data they'd float
back to the surface, satellite modem, phone

27
00:05:43,610 --> 00:05:50,610
home and do it all over again and based on
my understanding of how things went down,

28
00:05:51,550 --> 00:05:54,199
one person was like, well, these things are
really cool, you know, we're getting really

29
00:05:54,199 --> 00:05:59,949
data, we're not having to send people out
in boats at $40,000 a day but the problem

30
00:05:59,949 --> 00:06:05,259
is we can't actually control where they go,
they're like hot air balloons. So it was like

31
00:06:05,259 --> 00:06:12,099
what if we strap wings on them and underwater
gliders were born. Henry Stommel was one the

32
00:06:12,099 --> 00:06:16,949
people who wrote some kind of pioneering articles
on the potential applications of these things

33
00:06:16,949 --> 00:06:23,949
and what you see before you today between
the Scarlet Night, the Slocum, the Spray,

34
00:06:25,419 --> 00:06:31,759
it's become a very popular vehicle class simple
because the range you can cover for the amount

35
00:06:31,759 --> 00:06:38,759
of energy you have to store. The Scarlet Night
was one of the record holders, it was put

36
00:06:39,020 --> 00:06:44,830
together by Rutgers university, and it was
essentially a Slocum glider that had been

37
00:06:44,830 --> 00:06:50,650
loaded down with extra battery mass and stretched
out a little bit. It uses lithium CSC cells,

38
00:06:50,650 --> 00:06:56,389
is my understanding, which is kind of impressive
because the high test peroxide rocket fuel

39
00:06:56,389 --> 00:07:02,110
you see in the movie Moonraker as far as I
can tell has lower energy, so are pretty impressive

40
00:07:02,110 --> 00:07:09,110
batteries although also fairly expensive.
That's not what I ended up using. So I don't

41
00:07:11,460 --> 00:07:15,580
know if this is the correct way to design
an underwater glider but after going through

42
00:07:15,580 --> 00:07:20,990
10, 20 designs in my head before trying to
build the first draft this is kind of what

43
00:07:20,990 --> 00:07:27,270
I settled on as the proper procedure. Maybe
somebody can correct me if I'm wrong but you

44
00:07:27,270 --> 00:07:30,439
don't really know how you can your package
your components until you know what your components

45
00:07:30,439 --> 00:07:34,310
are, and buoyancy engine being one of the
key elements, it's going to determine the

46
00:07:34,310 --> 00:07:40,120
efficiency, you really have to start with
that. Energy storage system is going to be

47
00:07:40,120 --> 00:07:46,689
dictated by the energy requirements of your
buoyancy and then whole design, it's a pretty

48
00:07:46,689 --> 00:07:53,689
straightforward process. Very few moving parts.
So eventually I did, you know, I'm not a very

49
00:07:55,590 --> 00:07:59,580
decisive person but eventually I did come
to a conclusion on how I wanted to build one

50
00:07:59,580 --> 00:08:04,849
of these things and that's with a phase change
material. There's another vehicle out there

51
00:08:04,849 --> 00:08:11,699
that uses PCMs to propel itself through the
water, it's called the Slocum Thermal and

52
00:08:11,699 --> 00:08:18,699
I'm not doing that because it looked very
expensive. I read NASA tech briefs kind of

53
00:08:19,719 --> 00:08:23,580
talking about that aspect, and I think it
was like (inaudible) decking was the alkane

54
00:08:23,580 --> 00:08:28,539
they used and really expensive per ounce,
wasn't really on the table because my goal

55
00:08:28,539 --> 00:08:32,849
going into this ‑‑ because, remember,
I said I could do this for $100 if I'm spending

56
00:08:32,849 --> 00:08:39,849
$200 for my face change material I'm already
blown out. So these were the design requirements

57
00:08:41,909 --> 00:08:47,329
I went into it with. I wanted the barriers
to entry to be super slow because even though

58
00:08:47,329 --> 00:08:53,790
I had access to a milling machine and a lathe,
not everyone does so I wanted all of you to

59
00:08:53,790 --> 00:08:59,889
be able to take the DEF CON CD, take the solid
models that on there and go home and build

60
00:08:59,889 --> 00:09:06,260
one of these yourself. And then range of efficiency,
you're not going to take a two order of magnitude

61
00:09:06,260 --> 00:09:11,660
reduction in costs without taking some hits
on range, efficiency, performance. So it was

62
00:09:11,660 --> 00:09:18,660
kind of a best‑effort basis. I'm pretty
optimistic. I've got a fairly large battery

63
00:09:18,769 --> 00:09:24,089
pack compared to the currency, or compared
to the current consumption I'm looking at,

64
00:09:24,089 --> 00:09:31,089
so we'll see.
Here's one of the earlier efforts I made into

65
00:09:31,100 --> 00:09:38,100
actually trying to design for the manufacturer.
That's a Harbor Freight air compressor gear

66
00:09:38,800 --> 00:09:45,570
being used to index several syringes and this
design actually served as a little bit of

67
00:09:45,570 --> 00:09:52,060
inspiration for a hack I had to make towards
the end of this project. Overall the check

68
00:09:52,060 --> 00:09:57,500
valves involved were kind of a prohibitive
feature that just disillusioned me on this

69
00:09:57,500 --> 00:10:04,500
concept. So considering a lot of thing, I
struck out early on in the process because

70
00:10:04,940 --> 00:10:09,480
at the time a lathe and milling machine were
pretty much, you know, a requirement to make

71
00:10:09,480 --> 00:10:15,820
those happen. The weight of using off‑the‑shelf
linear actuator was pretty massive, you'd

72
00:10:15,820 --> 00:10:22,660
end up with a scuba tank pressure housing
and that's no fun. So wave and solar power

73
00:10:22,660 --> 00:10:26,810
interesting concepts, I'd like to explore
them a little bit especially for one concept

74
00:10:26,810 --> 00:10:33,810
I might mention at the end, but overall hydraulic
pumps and face change materials kind of showed

75
00:10:33,990 --> 00:10:40,990
out to me as the best choices available.
So paraffin wax expands 10 percent when it

76
00:10:42,009 --> 00:10:48,430
melts, ish. It's got a high specific heat
when it does melt it will stay liquid for

77
00:10:48,430 --> 00:10:54,680
a very long time. I was looking at using soldering
irons as a (unintelligible) to melt down the

78
00:10:54,680 --> 00:11:01,269
wax. And this was just kind of a breakdown
at the various energy densities I was looking

79
00:11:01,269 --> 00:11:07,920
at for ‑‑ kind of guiding my decision
on how to build the buoyancy engine. And when

80
00:11:07,920 --> 00:11:14,230
I first started on this project, there really
wasn't very much available of low‑cost inertial

81
00:11:14,230 --> 00:11:19,300
navigation. You had the multi‑weave project
which I thought was pretty ingenious, they

82
00:11:19,300 --> 00:11:25,160
took a Numchuk and a motion plus from a Wii
game console and they actually made an IMU

83
00:11:25,160 --> 00:11:32,070
something out of it. Welcome to the future.
This is really cool, a $33 board available

84
00:11:32,070 --> 00:11:37,670
from Hobby King, I can't imagine they have
more than $5 profit margin built into that.

85
00:11:37,670 --> 00:11:42,970
You get a really cutting‑edge chip on there
called an MPU 6050, or 60,000, on of the two

86
00:11:42,970 --> 00:11:47,970
depending on if it's SPI or ITC. But the point
is it's got a built‑in magnetometer, and

87
00:11:47,970 --> 00:11:53,519
so it can do complete 90‑degree freedom
sensor fusion which is the ability to distinguish

88
00:11:53,519 --> 00:12:00,380
between gravity and linear movement through
space. And when you're trying to actually

89
00:12:00,380 --> 00:12:07,000
integrate your inertial data, you'll run into
problems unless you have some pretty good

90
00:12:07,000 --> 00:12:11,110
math background or a fantastic product like
this behind you.

91
00:12:11,110 --> 00:12:18,110
That's a 3‑D R robotics GPS chip, it was
available and it's buried in the nose cone

92
00:12:18,720 --> 00:12:24,389
of my vehicle right now, coated in a nice,
thick goop of RGV compound.

93
00:12:24,389 --> 00:12:29,290
The whole design was kind of fun. I spent
most of the past year working on that specific

94
00:12:29,290 --> 00:12:34,519
aspect because it ultimately guided the production
of the rest of the vehicle, once I knew what

95
00:12:34,519 --> 00:12:41,519
I was packaging, I had to actually wrap it
up into some sort of fluid dynamic whole form

96
00:12:41,850 --> 00:12:46,769
and so based on the research I had, I'd heard
some interesting things about 30‑1 glide

97
00:12:46,769 --> 00:12:50,740
ratios with something called the McMasters
air foil which is pretty much well which is

98
00:12:50,740 --> 00:12:57,740
pretty much a NACA four‑digit series 0030,
but based on the simulations I did using a

99
00:13:01,110 --> 00:13:08,110
program called Profili 2 marketed at RC Plane
Design, its main claim to fame is it didn't

100
00:13:08,920 --> 00:13:15,920
stall out at high angles of attack whereas
the black line has one of the sharpest peaks

101
00:13:16,360 --> 00:13:23,329
on there so NACA 009 or 0009 was kind of out
of the question, too, so kind of middle of

102
00:13:23,329 --> 00:13:28,639
the road choice of this metric air foils who
were well understood at the time. Pretty common

103
00:13:28,639 --> 00:13:35,639
options are NACA 0015ish, so I think my wing
route is NACA 0015 and wing tip is NACA 002,

104
00:13:40,449 --> 00:13:47,449
and what that does is hopefully like the Rutan
Long EZ, if you end up stalling out, the wing

105
00:13:48,029 --> 00:13:53,819
route stalls before the wing tips and that
will cause the pitch to self‑correct. Fingers

106
00:13:53,819 --> 00:13:59,610
crossed on that. Not a lot of testing in that
regard.

107
00:13:59,610 --> 00:14:06,610
So first concept, I took a polycarbonate tube,
a wax motor used to control a dishwasher latch,

108
00:14:06,920 --> 00:14:13,389
funny enough, high‑force, high late answer,
low efficiency unfortunately as I found out

109
00:14:13,389 --> 00:14:20,389
later. And, oh, no, I'm not sure if I'd submitted
my CFIP at this point but I was kind of sweating

110
00:14:20,690 --> 00:14:27,690
at that point because I'm apparently really,
really bad at fiberglass. Who knew? The original

111
00:14:28,360 --> 00:14:33,470
idea was is that I would be using hot wire
foam techniques to actually generate the whole

112
00:14:33,470 --> 00:14:38,470
form and lay fiberglass over it and as you
can see from this picture that wasn't going

113
00:14:38,470 --> 00:14:45,470
so hot so not as easy as it looked on YouTube.
Was not going to hit my deadline at that rate.

114
00:14:45,699 --> 00:14:51,470
So throw money at the problem. I've generally
found that when time is of the essence money

115
00:14:51,470 --> 00:14:57,110
can generally buy you time back so I bought
a 3‑D printer. I really am happy I made

116
00:14:57,110 --> 00:15:01,009
that decision. 3‑D printers are really cool.
One of the design requirements being able

117
00:15:01,009 --> 00:15:05,940
to build this thing in my underwear ‑‑
check.

118
00:15:05,940 --> 00:15:11,699
So similar design, same whole form but now
broken into smaller chunks to help with the

119
00:15:11,699 --> 00:15:16,399
print volume and also, you know, trying to
minimize the overhang of the printed parts.

120
00:15:16,399 --> 00:15:23,399
Support material is an option and one of the
large parts actually was using support material.

121
00:15:23,600 --> 00:15:28,529
One month turnaround time, you really can't
argue with that. And I ‑‑ I knew 3‑D

122
00:15:28,529 --> 00:15:33,259
printing could really help expedite the design
process in getting you through multiple iterations

123
00:15:33,259 --> 00:15:39,160
but until I'd experienced it firsthand kind
of saving my bacon of getting a prove concept

124
00:15:39,160 --> 00:15:46,160
throughout the door and second, third revision,
whatever I was incredibly impressed with the

125
00:15:46,170 --> 00:15:51,129
value. The 3‑D printer was a road stock
max, it's a delta style design and they're

126
00:15:51,129 --> 00:15:58,129
one of the coolest when they're running. Cartesian
bots a little bit lame, in my opinion. And

127
00:15:59,160 --> 00:16:06,160
that's the robot you see in front of you so
$100 price target. $31 a kilogram for my plastic.

128
00:16:08,990 --> 00:16:13,139
That could be cheaper but let's, you know,
try and be generous just to make sure I don't

129
00:16:13,139 --> 00:16:20,069
underestimate. $21 in plastic. So if you throw
a significant amount of capital investment

130
00:16:20,069 --> 00:16:26,829
at the prospect of building injection molding
tooling, then, that could come down significantly.

131
00:16:26,829 --> 00:16:30,959
Remaining bill and ‑‑ building material
was actually published to the DVD if I remember

132
00:16:30,959 --> 00:16:36,899
correctly and I mentioned there may have been
some hiccups along the road, this building

133
00:16:36,899 --> 00:16:41,759
material is definitely not accurate to the
30‑cent mark because the face change material

134
00:16:41,759 --> 00:16:48,480
concept ended up working out to not just moderately
inefficient to virtually unworkable, at least

135
00:16:48,480 --> 00:16:52,509
with the energy storage system I selected.
If you need your robot to go to the bottom

136
00:16:52,509 --> 00:16:56,740
of the Marianas trench, the fact that it's
a solid‑to‑liquid phase change as opposed

137
00:16:56,740 --> 00:17:01,040
to expansion and contraction of gas really
work to your advantage, but if you're going

138
00:17:01,040 --> 00:17:06,240
for range and you don't particularly want
to be dragging bottom with seaweed, trying

139
00:17:06,240 --> 00:17:12,340
to get 3,000 meters of depth with that process
probably not the most efficient use of battery

140
00:17:12,340 --> 00:17:19,340
storage. So I think it was early May when
I realized, wow, I've got, you know, a 200‑volt

141
00:17:19,430 --> 00:17:26,430
pack or whatever and it's browning out at
100 milliamps, .1‑amp, I knew coin cells

142
00:17:26,480 --> 00:17:32,000
weren't exactly like lithium palm or RC plane
batteries but I was a little bit blown away

143
00:17:32,000 --> 00:17:38,590
so I needed a plan B, or plan C, I guess,
so what I came up with was something a little

144
00:17:38,590 --> 00:17:45,030
more conventional, you know, trying to avoid
too many experimental, you know, wild concepts

145
00:17:45,030 --> 00:17:50,790
in one vehicle build can be a life save her
so I went to the tried and true liquid motor

146
00:17:50,790 --> 00:17:56,660
linear actuator because if you remember those
aren't really an option because people wouldn't

147
00:17:56,660 --> 00:18:02,660
have access with a lathe and mill but with
a 3‑D printer that potentially changes so

148
00:18:02,660 --> 00:18:09,400
I ended up using commercial off‑the‑shelf
McMaster car parts to build the assembly which

149
00:18:09,400 --> 00:18:16,400
you can see white on the actual robot now.
So the only change between what's on your

150
00:18:16,450 --> 00:18:21,020
DVD and what actually is here in front of
you is the white assembly. Everything else

151
00:18:21,020 --> 00:18:28,020
I was able to recycle between designs. Modular
design is a good thing, I guess. The gray

152
00:18:28,740 --> 00:18:34,440
pipe was a really good choice it will ‑‑
sorry about that ‑‑ the gray pipe was

153
00:18:34,440 --> 00:18:40,150
a really good choice because it allowed for
routing of the wiring and ultimately acted

154
00:18:40,150 --> 00:18:47,150
as kind of a skeleton or a backbone for the
entire vehicle. So what I learned from that

155
00:18:47,750 --> 00:18:52,530
process is 3‑D printing's awesome and the
great thing is when you're actually done with

156
00:18:52,530 --> 00:18:57,940
it you don't have to go through an entire
twisted any process to design injection molding

157
00:18:57,940 --> 00:19:02,790
parts you're practically there when you have
a working prototype.

158
00:19:02,790 --> 00:19:07,820
What I learned through the process, I feel
like I actually hit a pretty good balance

159
00:19:07,820 --> 00:19:13,490
between fail early, fail often and not making
stupid mistakes for lack of planning. I didn't

160
00:19:13,490 --> 00:19:18,880
build anything before I had complete solid
model data. And that's really valuable when

161
00:19:18,880 --> 00:19:23,060
you're trying to avoid these last‑minute
crazed runs to Home Depot, West Marine, Auto

162
00:19:23,060 --> 00:19:27,160
Zone, whatever it is, if you have the complete
building materials before you make the first

163
00:19:27,160 --> 00:19:31,120
part, you know exactly what's going into the
thing and you don't find yourself running

164
00:19:31,120 --> 00:19:37,790
into these issues where parts are colliding
with each other so ‑‑ and then it was

165
00:19:37,790 --> 00:19:42,920
also extremely difficult to quantify whether
or not a design decision was a good or a bad

166
00:19:42,920 --> 00:19:49,780
one such as the wax motor until actually trying
it. So it was a design decision trade‑off

167
00:19:49,780 --> 00:19:55,800
to not use so much simulation and I was pretty
happy with how that went because you can simulate

168
00:19:55,800 --> 00:20:02,070
the daylights out of a bad idea and then find
out you wasted the last year doing, you know,

169
00:20:02,070 --> 00:20:09,070
FEA or CFD on a broken design and then it's
all wasted so prototypes can little nature

170
00:20:09,340 --> 00:20:13,850
things that you otherwise wouldn't be aware
of.

171
00:20:13,850 --> 00:20:20,160
So I did this entire thing out‑of‑pocket.
No ‑‑ no grants or funding agencies and

172
00:20:20,160 --> 00:20:26,340
I actually really like that because I'm accountable
to myself and I don't have anybody breathing

173
00:20:26,340 --> 00:20:32,970
down my neck, forcing me to, you know, chase
some costs or make bad decisions because,

174
00:20:32,970 --> 00:20:38,140
oh, I need to save face over that, you know,
thousand dollars I wasted on, you know, wax

175
00:20:38,140 --> 00:20:45,140
motors. On the other hand, I gave pretty much
the profit of the design away for free on

176
00:20:45,170 --> 00:20:50,190
the DVD this year. I probably spent around
15 grand on the project over the past decade.

177
00:20:50,190 --> 00:20:57,140
And so I would consider it a dubious appropriation
of my retirement savings. But, you know, that

178
00:20:57,140 --> 00:21:01,710
was the mission from the start. I wanted people
to be able to build these themselves and kind

179
00:21:01,710 --> 00:21:08,710
of empower themselves to deliver sensors,
communications devices and payloads to remote

180
00:21:10,440 --> 00:21:16,840
destinations where traditionally it would
be prohibitively expensive at, you know, tens

181
00:21:16,840 --> 00:21:23,840
of thousands of dollars per vehicle. And how
that's possible is if your price is low enough

182
00:21:23,970 --> 00:21:29,570
you can consider it disposable and you don't
have to pay somebody 40 grand to go out and

183
00:21:29,570 --> 00:21:35,220
water and change the batteries.
So we'll see. Ultimately if you build it they

184
00:21:35,220 --> 00:21:39,920
will come and if it's a good idea hopefully
people will say, hey, maybe we should build

185
00:21:39,920 --> 00:21:45,710
some of these.
So where to go from here? I didn't have an

186
00:21:45,710 --> 00:21:52,710
opportunity to test max depth because I only
had one prototype as of two weeks ago and

187
00:21:53,840 --> 00:21:57,050
I didn't really want to lose it out in the
ocean scuba diving like, I guess, I could

188
00:21:57,050 --> 00:22:03,910
have tried to put a dog collar on it and walked
it like with a leash but overall it's disposable

189
00:22:03,910 --> 00:22:09,480
after my talk is over but the thing took over
100 hours to print and, actually, that guy

190
00:22:09,480 --> 00:22:14,370
right there put in a significant amount of
labor helping getting ready for your guyses'

191
00:22:14,370 --> 00:22:19,820
eyes so small applause for him, if you're
willing.

192
00:22:19,820 --> 00:22:26,820
[APPLAUSE]
 Thanks, guys. So in terms of trimming vehicle,

193
00:22:28,730 --> 00:22:33,610
I can say with high degree of certainty this
thing is very positively bouyant. Traditional

194
00:22:33,610 --> 00:22:39,210
buoyancy foam, polyurethane, or epoxy and
glass micro balloons. High‑crush depth kind

195
00:22:39,210 --> 00:22:44,790
of unnecessary seeing as how I designed the
vehicle with syringes, but overall a good

196
00:22:44,790 --> 00:22:51,790
choice. So generally speaking, epoxy or urethane,
I chose paraffin wax, it's lost cost and over

197
00:22:52,620 --> 00:22:59,410
half the dollar per pound of buoyancy I was
seeing was either epoxy or urethane, so paraffin

198
00:22:59,410 --> 00:23:06,250
wax is like $4 a pound. So very positively
bouyant, every empty cavity in that entire

199
00:23:06,250 --> 00:23:10,700
thing has a specific gravity about .5 so it's
really just a matter of how you distribute

200
00:23:10,700 --> 00:23:15,990
your lead and batteries at this point to make
sure that when the buoyancy engine's in neutral

201
00:23:15,990 --> 00:23:22,700
position it's sending about horizontal because
when the vehicle goes buoyancy the center

202
00:23:22,700 --> 00:23:29,200
of buoyancy moves the vehicle and it pitches
toward the suffered and the GPS chip rises

203
00:23:29,200 --> 00:23:36,200
up towards daylight and when it goes negatively
bouyant the opposite happens. So if you're

204
00:23:37,620 --> 00:23:42,540
in neutral buoyancy you should be sitting
around level in the water and it's really

205
00:23:42,540 --> 00:23:49,360
just a matter of adding weight and removing
buoyancy foam as necessary to achieve that,

206
00:23:49,360 --> 00:23:56,360
I'm looking at around 40 to 50 milliliters
of displacement change. So it's unknown at

207
00:23:57,000 --> 00:24:02,320
this time what the vehicle's velocity through
the water is, the more bouyant it is the fast

208
00:24:02,320 --> 00:24:06,100
e it's going to pop to the surface like a
cork and your speed through the water is going

209
00:24:06,100 --> 00:24:12,080
to determine what the Reynolds number is and
that guides, you know, things like what air

210
00:24:12,080 --> 00:24:19,010
flow you select. But first draft, I'd call
it an alpha stage design and openglider.com

211
00:24:19,010 --> 00:24:26,010
is where I'm going to be adding future revisions.
The one on your CD is rev0.1, and rev 0.2

212
00:24:28,040 --> 00:24:35,040
will be on openglider.com tonight and that
will be have 9 new white syringe‑based assembly

213
00:24:37,580 --> 00:24:44,580
so yeah. In terms of research that went into
this, this guy named Bruce Carmichael was

214
00:24:45,140 --> 00:24:51,990
one of the pioneers of the airfoil you see
before you. It's called the X‑35 and originally

215
00:24:51,990 --> 00:24:58,050
it was known as the Dolphin but if I understand
correctly they ran the Dolphin through a genetic

216
00:24:58,050 --> 00:25:05,050
algorithm and ultimately the citation shaping
of axonometric bodies from minimum drag, that

217
00:25:08,130 --> 00:25:13,340
one was I think was where I was able to find
the coordinates for this design. It does bear

218
00:25:13,340 --> 00:25:17,470
some resemblance to some other vehicles on
the market and that shouldn't be too surprising

219
00:25:17,470 --> 00:25:24,470
seeing as as far as I can tell we did use
the same curve rotate around its axis to generate

220
00:25:26,980 --> 00:25:33,980
the main body. Otherwise, the NACA four‑digit
series, pretty common equation. And I threw

221
00:25:35,500 --> 00:25:42,070
something in here that I found really fascinating.
It's the geometry of a blended wing body morphing

222
00:25:42,070 --> 00:25:48,370
wing and that was the idea that you could
actually design an entire vehicle around variables

223
00:25:48,370 --> 00:25:55,370
and equations so you can change something
like a static wing sweep from 30 degrees

224
00:25:56,280 --> 00:26:02,430
to 15 to 25 degrees and rather than having
a lot of hard engineering labor going into

225
00:26:02,430 --> 00:26:09,430
remaking the entire design it just regenerates
itself so I very early on in the process I

226
00:26:09,590 --> 00:26:14,240
was trying to stick to that concept and I
was pretty pleased. I would change a variable

227
00:26:14,240 --> 00:26:21,240
from like a NACA of four digit 002 to NACA
at 005, you know, kind of crazy, and hit rebuild

228
00:26:23,000 --> 00:26:28,490
and the model would regenerate itself with
very little labor on my part. One thing I'd

229
00:26:28,490 --> 00:26:33,500
like to explore is potentially even doing
a genetic algorithm around that concept to

230
00:26:33,500 --> 00:26:40,500
optimize for parameters like speed through
the water column and lift‑to‑drag ratio.

231
00:26:45,340 --> 00:26:51,750
So that's pretty much how I got here. The
X‑35 took me like six months to a year to

232
00:26:51,750 --> 00:26:55,870
even find. I had no idea where people were
getting this curve from but I saw it in several

233
00:26:55,870 --> 00:27:02,870
places. Ultimately it was just a mad Google
foo that was able to illuminate the coordinates

234
00:27:04,050 --> 00:27:11,050
to build this thing. And in terms of other
information on how to build an underwater

235
00:27:12,270 --> 00:27:19,270
vehicle, I was going to joke, you know, every
story's hero has a favorite weapon. Rock Sampson's

236
00:27:20,630 --> 00:27:27,630
Bowie knife, Will Smith's little cricket and
Flipper's hot glue gun. When you're try to

237
00:27:29,610 --> 00:27:35,140
waterproof stuff, I've tried a lot of different
things, (unintelligible) coat, epoxy potting

238
00:27:35,140 --> 00:27:40,780
and pressure housings and overall, even paraffin
wax, actually ‑‑ it's not going to do

239
00:27:40,780 --> 00:27:47,780
very good in the Caribbean where the water
gets down there 80 degrees Celsius. And so ‑‑

240
00:27:51,640 --> 00:27:56,490
but it does a pretty good job because when
you pot your electronics in epoxy it's difficult

241
00:27:56,490 --> 00:28:01,790
to recover them or repair them if something
blows up. But when you're using paraffin wax

242
00:28:01,790 --> 00:28:06,700
the 80‑degree C melting temperature is actually
below the rated temperature for most electronics

243
00:28:06,700 --> 00:28:11,550
so if you decide you want to change something
about them, and I've had to, you can just

244
00:28:11,550 --> 00:28:18,550
use a hot air gun or boiling water to rescue
your electronics. That said, from a durability

245
00:28:18,830 --> 00:28:24,070
standpoint, paraffin wax, even if you anneal
it with a little bit of mineral oil, not the

246
00:28:24,070 --> 00:28:30,230
most durable thing ever. So ultimately hot
glue has been my favorite approach to waterproofing

247
00:28:30,230 --> 00:28:34,010
and if you need something a little bit lower
viscosity, get down in the English muffin

248
00:28:34,010 --> 00:28:41,010
nooks and crannies then they make low‑viscosity
silicone RTV. The acetic acid can potentially

249
00:28:41,500 --> 00:28:45,510
corrode your electrical contacts, but we're
talking about disposable vehicles here. It

250
00:28:45,510 --> 00:28:50,190
doesn't have to last three years. I've got
electronic speed controllers I potted for

251
00:28:50,190 --> 00:28:56,140
a competition two years ago that still work
and that was just plain Jane Auto Zone RTV

252
00:28:56,140 --> 00:29:02,350
compound. And so pretty much every piece of
electronics on that thing are just either

253
00:29:02,350 --> 00:29:08,650
coated in hot glue or RTV compound and it's
a pretty easy low‑cost way of waterproofing

254
00:29:08,650 --> 00:29:15,650
electronics. So I guess at this time it would
be a good way to go for questions.

255
00:29:18,010 --> 00:29:25,010
 (Off mic).
 Yeah, that's a good yes so one of the problems

256
00:29:29,820 --> 00:29:36,290
with the underwater vehicles that is interesting
to me, unlike mars rovers, you know, easy

257
00:29:36,290 --> 00:29:42,880
environment, you know, aerial vehicles, bunch
of light weights, you know, these people,

258
00:29:42,880 --> 00:29:46,370
they're so spoiled, with underwater vehicles
you don't get to talk to your robot after

259
00:29:46,370 --> 00:29:51,390
you let it go until it comes back to the surface
at which point it's kind of a surface vehicle

260
00:29:51,390 --> 00:29:56,700
until it goes back under water snorkel depth
style. So no radio frequency communication

261
00:29:56,700 --> 00:30:01,560
so it has to be pretty much ought autonomous
and the source code I used with the IMU to

262
00:30:01,560 --> 00:30:07,770
actually ‑‑ it's called a Haversine formula,
it finds your current GPS coordinates and

263
00:30:07,770 --> 00:30:12,930
your destination GPS coordinates and gives
you a bearing and the distance you need to

264
00:30:12,930 --> 00:30:17,470
go to get there. So it's pretty much a line‑follower
robot, that's what makes underwater gliders

265
00:30:17,470 --> 00:30:24,470
potentially so successful unlike mine‑detecting
robots or antifrogman stuff. They have a pretty

266
00:30:25,660 --> 00:30:30,090
basic mission which is to go from point A
to point B. So object avoidance potentially

267
00:30:30,090 --> 00:30:34,570
with sonar, but suddenly when your payload
starts getting into the high‑dollar sonar

268
00:30:34,570 --> 00:30:41,080
stuff it stops being so disposable. At that
point my 3‑D printed open glider may not

269
00:30:41,080 --> 00:30:47,970
be the best choice of vehicles.
 (Off mic).

270
00:30:47,970 --> 00:30:53,070
 Um, so testing has been kind of an iterative
process. I've learned every time I stuck it

271
00:30:53,070 --> 00:31:00,060
in the bathtub, early on it was pretty much
with a small car battery and some red and

272
00:31:00,060 --> 00:31:05,140
green wire hanging out of the thing. Underwater
vehicles can actually be communicated with

273
00:31:05,140 --> 00:31:11,260
remotely using something called a tether at
which point they're no longer AAVs or UUVs

274
00:31:11,260 --> 00:31:15,730
they're ROVs, they're remotely operated vehicles.
And I had two years of tethered vehicle competitions

275
00:31:15,730 --> 00:31:22,730
that kind of prepared me for working with
the unmanned side of things. And it's a pretty

276
00:31:23,390 --> 00:31:29,540
good way to go. So for testing, bathtubs or
surprisingly effective. You have them in hotel

277
00:31:29,540 --> 00:31:36,540
rooms. And, yeah, generally speaking, the
main thing you're going to be testing is either

278
00:31:37,060 --> 00:31:41,400
what it decides to do when it gets in the
water or how it sits in the water when you

279
00:31:41,400 --> 00:31:46,860
put it in there and both of those things don't
require a big swimming pool. Also a lot less

280
00:31:46,860 --> 00:31:53,860
terrified sleeking swimmers running away from
the evil robot.

281
00:31:56,779 --> 00:32:03,779
 (Off mic).
 It's the second one. So I don't really

282
00:32:11,920 --> 00:32:18,920
rely on pressurizing as a rule. I had to depend
on some amount of air cavity for the design

283
00:32:21,040 --> 00:32:27,170
fix and it's the most conventional thing about
this design was you've got one of your actuators

284
00:32:27,170 --> 00:32:33,290
driven by three‑volt gear motors, actually,
I think I have one, anybody want one? I know

285
00:32:33,290 --> 00:32:40,290
audiences love things being thrown at them.
Not you, Mark. Ooh, hey, speaking of that,

286
00:32:41,920 --> 00:32:48,920
anybody want a flight controller, $33 gimme?
Remember two is one, one is none so bring

287
00:32:49,210 --> 00:32:56,210
spare parts. Oops. Sorry. I throw like a roboticist.
More questions?

288
00:33:00,570 --> 00:33:07,570
 (Off mic).
 Oh, good question. So when you have like

289
00:33:09,480 --> 00:33:14,880
a tank light when you're scuba diving you
can make them light not wasting battery life

290
00:33:14,880 --> 00:33:20,630
and trying not to lose your dive buddy. In
my case I don't have anything smart like that

291
00:33:20,630 --> 00:33:27,410
on my robot, those wires allow me to disconnect
the power supply from the micro controller.

292
00:33:27,410 --> 00:33:32,350
Once I plug it in it goes and keep going until
I unplug it.

293
00:33:32,350 --> 00:33:37,000
 (Off mic).
 Good question. I was on a ROV conference,

294
00:33:37,000 --> 00:33:41,080
and this guy was like super salty, had been
out in the field for a long time and told

295
00:33:41,080 --> 00:33:45,290
me a really cool trick. You go to like Harbor
Freight and they'll sell these heat shrink

296
00:33:45,290 --> 00:33:49,950
packages, marine heat shrink, and it's just
heat shrink that's been lined with hot glue

297
00:33:49,950 --> 00:33:55,480
and you don't need to use special heat shrinker
wire crimps, you can just take your wire splice,

298
00:33:55,480 --> 00:34:01,530
coat it in hot glue and then run heat shrink
over it and then when you heat the heat shrink

299
00:34:01,530 --> 00:34:06,559
it will melt the hot glue again and pull all
the air bubbles out. Great question.

300
00:34:06,559 --> 00:34:10,849
 (Off mic).
 How does it what?

301
00:34:10,849 --> 00:34:15,329
 (Off mic).
 Oh, yeah, no, I totally glossed over on

302
00:34:15,329 --> 00:34:21,329
that. Really good point. I don't actually
have one buoyancy engine, I have four. And

303
00:34:21,329 --> 00:34:26,019
generally speaking, I might have them towards
the top of the vehicle. I have them low on

304
00:34:26,019 --> 00:34:32,019
the center of gravity because I had two places
I could put them top or bottom and the top

305
00:34:32,019 --> 00:34:39,019
was all being used by syntactic foam or syntactic
wax, buoyancy sandy and since that was more

306
00:34:39,210 --> 00:34:44,529
bouyant than the buoyancy engines themselves
I had them down low and so I have broken the

307
00:34:44,529 --> 00:34:51,529
cross‑section of my vehicle into eight little
slices of pie. The top four are pull of buoyancy

308
00:34:51,639 --> 00:34:58,639
sand and the bottom four, there are two pairs.
So when you trigger the two on the left, your

309
00:35:00,279 --> 00:35:07,279
left side is going to be more bouyant than
your right side so one wing will lift up and

310
00:35:07,640 --> 00:35:12,789
likewise if you use the two on the right it's
going to change the attitude the other way.

311
00:35:12,789 --> 00:35:17,599
So this is one unique thing about my vehicle
design, traditionally you actually use your

312
00:35:17,599 --> 00:35:23,079
battery mass whereas I'm just having four
times the buoyancy engines that are typical.

313
00:35:23,079 --> 00:35:27,029
And finally, you know, if you ‑‑ you
change buoyancy on the bottom two then you'll

314
00:35:27,029 --> 00:35:34,029
just go straight.
 (Off mic).

315
00:35:39,109 --> 00:35:46,109
 Good question. I can say with before is
pretty good confidence my inertial confidence

316
00:35:49,839 --> 00:35:56,839
is not high enough quality to be U.S. munitions
grid. That's total relief. These are hobby

317
00:35:58,039 --> 00:36:05,039
components. Video game grade. In terms of
actual like integration of my, you know, velocity

318
00:36:06,390 --> 00:36:12,029
or whatever to get my position I don't really
do any of that. I've been working a little

319
00:36:12,029 --> 00:36:18,890
bit in my free time with trying to use fetal
Doppler monitors which measure the velocity

320
00:36:18,890 --> 00:36:25,109
of fluid through babies' blood to, you know,
let you listen to the kid's heartbeat, kind

321
00:36:25,109 --> 00:36:31,460
of cool and they're ultrasonic homo dines
and I've been potentially getting velocity

322
00:36:31,460 --> 00:36:35,319
information from that but pretty much I figure
out which direction I want to go and it's

323
00:36:35,319 --> 00:36:41,349
a line fall robot it says I know I want to
go left, right, or straight and it comes to

324
00:36:41,349 --> 00:36:48,220
the surface, oh, wow I missed my target but
OK, it doesn't look backwards, only forward.

325
00:36:48,220 --> 00:36:53,380
Good question, thanks.
 (Off mic).

326
00:36:53,380 --> 00:37:00,380
 Oh, bathtub depth?
 (Off mic).

327
00:37:01,840 --> 00:37:07,720
 Originally I had a washing machine wax
motor, like I think it was a whirlpool, Neptune

328
00:37:07,720 --> 00:37:14,720
or something. And that one didn't get a lot
of mileage simply because the fiberglass thing

329
00:37:15,880 --> 00:37:20,480
went so terrible, just didn't really work
into the 3‑D printed picture. So then I

330
00:37:20,480 --> 00:37:24,509
worked to a soldering iron based design. I
was using silicone high‑temperature rubber

331
00:37:24,509 --> 00:37:31,140
hose and soldering irons and filling them
with wax and I was browning out my power supply.

332
00:37:31,140 --> 00:37:35,369
Even though I only needed about 100 milliamps,
it was still too much, and it would have been

333
00:37:35,369 --> 00:37:42,369
a pretty big design tearup to change my batteries
so I just changed my buoyancy engine. Questions?

334
00:37:45,790 --> 00:37:52,790
 (Off mic).
 Really good question. So and the original

335
00:37:54,079 --> 00:37:59,539
solid model I designed around, I actually
made a solid model of the PX‑4 auto pilot

336
00:37:59,539 --> 00:38:05,339
from the drones or PX ‑‑ I don't really
know what the relationship is but it's a really

337
00:38:05,339 --> 00:38:12,339
good board it uses a publisher‑subscriber
system so right now I'm only using the IMU,

338
00:38:12,369 --> 00:38:19,369
the micro Wii board for everything and one
of the issues with that decision is it is

339
00:38:21,089 --> 00:38:26,039
so flash memory constrained that you can only
just barely compile the source code included

340
00:38:26,039 --> 00:38:31,619
on your DVD. In fact, if you try and use Arduino
1.5.2 to do so, it's not going to work for

341
00:38:31,619 --> 00:38:38,619
you, you have to use Arduino 1.0.4, if I remember
correctly and that will work, and I didn't

342
00:38:39,730 --> 00:38:44,140
remember to put that in the slides and I'm
glad you brought it up. So there is a reasonable

343
00:38:44,140 --> 00:38:50,119
amount of space, about one‑quarter of the
size of an Altoid tin, maybe half the size

344
00:38:50,119 --> 00:38:57,019
of an Altoid tin for a supervisory controller
to supplement the IMU. The IMU is broadcasting

345
00:38:57,019 --> 00:39:02,650
yaw, pitch, roll information, that's already
been fused so it's pretty much relative to

346
00:39:02,650 --> 00:39:09,000
your world coordinate system and it's really
nice because it's publishing it on the serial

347
00:39:09,000 --> 00:39:14,029
port and it's also telling you ‑‑ oops,
time's up?

348
00:39:14,029 --> 00:39:20,450
All right, any further questions or wanting
to see the robot in person, you know, touch

349
00:39:20,450 --> 00:39:27,450
and feel? I'll meet you guys out in the hallway,
I guess.

350
00:39:28,859 --> 00:39:30,170
[APPLAUSE]