U.S. patent application number 13/646737 was filed with the patent office on 2013-04-25 for wave power.
The applicant listed for this patent is Robert Burcham, Derek L. Hine, Roger G. Hine, Kurt A.F. Kiesow, Joseph D. Rizzi, William A. Stutz. Invention is credited to Robert Burcham, Derek L. Hine, Roger G. Hine, Kurt A.F. Kiesow, Joseph D. Rizzi, William A. Stutz.
Application Number | 20130102207 13/646737 |
Document ID | / |
Family ID | 40538741 |
Filed Date | 2013-04-25 |
United States Patent
Application |
20130102207 |
Kind Code |
A1 |
Hine; Roger G. ; et
al. |
April 25, 2013 |
Wave Power
Abstract
A wave-powered water vehicle includes a surface float, a
submerged swimmer, and a tether which connects the float and the
swimmer, so that the swimmer moves up and down as a result of wave
motion. The swimmer includes one or more fins which interact with
the water as the swimmer moves up and down, and generate forces
which propel the vehicle forward. The vehicle, which need not be
manned, can carry communication and control equipment so that it
can follow a course directed by signals sent to it, and so that it
can record or transmit data from sensors on the vehicle.
Inventors: |
Hine; Roger G.; (Menlo Park,
CA) ; Hine; Derek L.; (Portola Valley, CA) ;
Rizzi; Joseph D.; (Los Altos, CA) ; Kiesow; Kurt
A.F.; (San Jose, CA) ; Burcham; Robert;
(Anchorage, AL) ; Stutz; William A.; (San Jose,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hine; Roger G.
Hine; Derek L.
Rizzi; Joseph D.
Kiesow; Kurt A.F.
Burcham; Robert
Stutz; William A. |
Menlo Park
Portola Valley
Los Altos
San Jose
Anchorage
San Jose |
CA
CA
CA
CA
AL
CA |
US
US
US
US
US
US |
|
|
Family ID: |
40538741 |
Appl. No.: |
13/646737 |
Filed: |
October 8, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12082457 |
Apr 11, 2008 |
8287323 |
|
|
13646737 |
|
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Current U.S.
Class: |
440/9 |
Current CPC
Class: |
Y02T 70/5236 20130101;
B63H 19/02 20130101; Y02T 70/59 20130101; B63H 2025/028 20130101;
B63H 2025/045 20130101; B63B 2035/006 20130101; B63H 1/36 20130101;
B63H 19/04 20130101; B63H 25/04 20130101 |
Class at
Publication: |
440/9 |
International
Class: |
B63H 19/04 20060101
B63H019/04 |
Claims
1. A wave-powered water vehicle which comprises (1) a float, (2) a
swimmer, and (3) a tether connecting the float and the swimmer; the
float, swimmer and tether being such that, when the vehicle is in
still water, (i) the float is on or near the surface of the water,
(ii) the swimmer is submerged below the float, and (iii) the tether
is under tension; the swimmer comprising (2a) a swimmer body having
a longitudinal axis, and (2b) a fin system which (a) is secured to
the body, (b) comprises a fin, and (c) when the device is in
wave-bearing water, (i) has a configuration which changes as a
result of the wave motion, and (ii) interacts with the water to
generate forces which tend to move the swimmer in a horizontal
direction; the device having one or more of the following
characteristics: (A) the fin system comprises a fin which rotates
about an axis of rotation, the axis of rotation having a spatial
relationship to the swimmer body which changes when the vehicle is
in wave-bearing water; (B) the fin system comprises (i) a fin which
rotates about an axis of rotation, and (ii) an elastic component
which is not part of the fin, and which deforms elastically and
thus influences changes in the configuration of the fin system when
the vehicle is in wave-bearing water; (C) the fin system comprises
a fin having a leading edge which comprises (i) a relatively rigid
central section which has a fixed spatial relationship with the
swimmer body, and (ii) relatively deformable outboard sections; (D)
the fin system comprises two generally laminar fins, each of which
rotates about an axis of rotation generally aligned with the
longitudinal axis of the swimmer body; (E) the tether comprises an
elastically deformable member; (F) the tether comprises a component
which transmits data and/or electrical power; (G) the swimmer body
has a substantially rigid fore section, a midsection which is
relatively flexible in the vertical plane, and a substantially
rigid aft section; (H) the swimmer body comprises one or more
components selected from electrical equipment, communications
equipment, recording equipment, control electronics, steering
equipment, and sensors; (I) the swimmer comprises a fin which
influences the orientation of the swimmer body in the horizontal
plane when the device is in the water-bearing water; (J) the device
is a water vehicle which moves in a horizontal direction when the
device is in wave-bearing water; (K) the swimmer comprises a
swimmer body comprising a central tubular housing and wave-actuated
fins which extend either side of the housing; and (L) the swimmer
body comprises a generally tubular housing and vertical fin
surfaces respectively adjacent to the leading end and the trailing
end of the swimmer body.
2. A water vehicle according to claim 1 which has characteristic
(A), and wherein the fin is a generally laminar fin and the axis of
rotation is generally transverse to the longitudinal axis of the
swimmer body.
3. A water vehicle according to claim 1 which has characteristic
(B), and wherein the fin is a generally laminar fin and the axis of
rotation is generally transverse and longitudinal axis of the
swimmer body, and the elastic component is a spring or torsion
bar.
4. A water vehicle according to claim 3 wherein the generally
laminar fin is elastically deformable and the elastic component is
a torsion bar mounted to the leading edge of the generally laminar
fin.
5. A water vehicle according to claim 1 wherein the fin is
generally laminar and elastically deformable, and the rigid central
section rotates about an axis of rotation having a fixed spatial
relationship with the swimmer body.
6. A water vehicle according to claim 5 wherein the fin is the sole
elastic component of the fin system
7. A wave-powered water vehicle which comprises (1) a float, (2) a
swimmer, (3) a tether connecting the float and the swimmer, and (4)
a computer system; the float, swimmer and tether being such that,
when the vehicle is in still water, (i) the float is on or near the
surface of the water, (ii) the swimmer is submerged below the
float, and (iii) the tether is under tension; the swimmer, when the
vehicle is in wave-bearing water, interacting with the water to
generate forces which tend to move the float horizontally; the
float comprising a satellite-based position sensor; the swimmer
comprising (a) a horizontal sensor which senses direction in a
horizontal plane, and (b) a steering actuator; and the computer
system (a) being linked to the position sensor, the horizontal
sensor and the rudder, (b) containing, or being programmable to
contain, instructions to control the steering actuator in response
to signals received from the position sensor and the horizontal
sensor, or in response to signals received from a sensor on the
vehicle.
8. A water vehicle according to claim 7 wherein the horizontal
sensor is a magnetic compass and the steering actuator is a
rudder.
9. A water vehicle according to claim 7 wherein the swimmer has a
center of gravity, and the tether is attached to the swimmer
substantially vertically above the center of gravity.
10. A water vehicle according to claim 7 wherein the float has a
center of buoyancy, and tether is attached to the float
substantially vertically below the center of buoyancy.
11. A water vehicle according to claim 7 of wherein the float has a
center of drag, and the tether is attached to the float in front of
the center of drag.
12. A method of utilizing wave power which comprises placing a
device according to claim 1 in a body of water which has or which
is expected to have water waves traveling across its surface.
13. A method of utilizing wave power which comprises placing a
device according to claim 7 in a body of water which has or which
is expected to have water waves traveling across its surface.
14. A novel component, for example a float, a swimmer, a swimmer
body, or a fin system substantially as described herein.
15. A method of obtaining information which comprises analyzing
information obtained from or recorded by a water vehicle according
to claim 1.
16. A method of obtaining information which comprises analyzing
information obtained from or recorded by a water vehicle according
to claim 7.
17. A method for controlling a function of a water vehicle
according to claim 1 which comprises sending signals to the water
vehicle.
18. A method for controlling a function of a water vehicle
according to claim 7 which comprises sending signals to the water
vehicle.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
12/082457, filed Apr. 11, 2008. application Ser. No. 12/082457 is a
continuation of application Ser. No. 11/436,447, filed May 18,
2006, which claims priority from provisional patent application No.
60/760,893, filed Jan. 20, 2006. The entire disclosure of each of
those earlier applications is Incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] This invention relates to the utilization of the power of
waves in water (hereinafter "wave power").
[0003] As a wave travels along the surface of water, it produces
vertical motion, but no net horizontal motion, of water. The
amplitude of the vertical motion decreases logarithmically with
depth; at a depth of about half the wave length, there is little
vertical motion. The speed of currents induced by wind also
decreases sharply with depth. A number of proposals have been made
to utilize wave motion to do useful work. Reference may be made,
for example, to U.S. Pat. Nos. 986,627, 1,315,267, 3,312,186,
3,453,981, 3,508,516, 3,845,733, 3,872,819, 3,928,967, 4,332,571,
4,371,347, 4,389,843, 4,598,547, 4,684,350, 4,842,560, 4,968,273,
5,084,630 and 6,561,856. The entire disclosure of each of those
patents is incorporated herein by reference for all purposes.
SUMMARY OF INVENTION
[0004] In accordance with the present invention, we have discovered
a wide variety of ways in which wave power can be utilized,
including novel water vehicles, novel components which are useful
for wave-powered water vehicles and for other purposes, and novel
methods using wave-powered water vehicles. In preferred
embodiments, the invention makes it possible for an unmanned water
vehicle to carry out tasks which would be tedious, expensive or
dangerous to carry out using a vehicle operated by human
beings.
[0005] In a first preferred aspect, this invention provides a
wave-powered device which comprises [0006] (1) a float, [0007] (2)
a swimmer, and [0008] (3) a tether connecting the float and the
swimmer; the float, swimmer and tether being such that, when the
vehicle is in still water, [0009] (i) the float is on or near the
surface of the water, [0010] (ii) the swimmer is submerged below
the float, and [0011] (iii) the tether is under tension; the
swimmer comprising [0012] (2a) a swimmer body having a longitudinal
axis, and [0013] (2b) a fin system which [0014] (a) is secured to
the body, [0015] (b) comprises a fin, and [0016] (c) when the
device is in water having waves moving across the surface of the
water (hereinafter wave-bearing water), [0017] (i) has a
configuration which changes as a result of the wave motion, and
[0018] (ii) interacts with the water to generate forces which tend
to move the swimmer in a direction having a horizontal component
(hereinafter referred to simply as "in a horizontal
direction").
[0019] The term "fin" is used herein to denote a component
comprising a generally laminar surface against which, when the
device moves relative to water in which the device is positioned,
the water exerts pressure sufficient to substantially influence the
movement of the device. The "longitudinal axis" of the swimmer body
lies in the generally vertical plane along which the swimmer moves
when the device is in wave-bearing water. Usually, but not
necessarily, the dimension of the swimmer body measured along the
longitudinal axis will be substantially greater than the dimension
of the swimmer body measured transverse to the longitudinal
axis.
[0020] The device preferably has at least one of (i.e. one or more
of) the following characteristics
[0021] (A) the fin system comprises a fin, for example a generally
laminar fin, which rotates about an axis of rotation (e.g. an axis
of rotation generally transverse to the longitudinal axis of the
swimmer body), the axis of rotation having a spatial relationship
to the swimmer body which changes when the device is in
wave-bearing water;
[0022] (B) the fin system comprises (i) a fin, for example a
generally laminar fin, which rotates about an axis of rotation
(e.g. an axis of rotation generally transverse to the longitudinal
axis of the swimmer body), and (ii) an elastic component (e.g. a
metal coil spring, a metal leaf spring, a metal torsion bar, or an
elastomeric component such as a natural or artificial rubber band)
which is not part of the fin, and which deforms elastically and
thus influences changes in the configuration of the fin system when
the device is in wave-bearing water;
[0023] (C) the fin system comprises a fin, for example a generally
laminar and elastically deformable fin, having a leading edge which
comprises (i) a relatively rigid central section which has a fixed
spatial relationship with the swimmer body (including the
possibility that the central section rotates about an axis of
rotation having a fixed spatial relationship with the swimmer
body), and (ii) relatively deformable outboard sections;
[0024] (D) the fin system comprises two generally laminar fins, for
example two generally laminar and elastically deformable fins which
are mirror images of each other, and each of which rotates about an
axis of rotation generally aligned with the longitudinal axis of
the swimmer body (such fins operate in a manner similar to the
pectoral fins on a fish or the wings on a bird, and are referred to
herein as "pectoral" fins);
[0025] (E) the tether comprises an elastically deformable
member;
[0026] (F) the tether comprises a component which transmits data
and/or electrical power;
[0027] (G) the swimmer body has a substantially rigid fore section,
a midsection which is relatively flexible in the vertical plane,
and a substantially rigid aft section, the tether being attached,
for example, to the fore section, and the fin system being
attached, for example, to the fore section;
[0028] (H) the swimmer body comprises one or more components
selected from electrical equipment, communications equipment,
recording equipment, control electronics, steering equipment, and
sensors;
[0029] (I) the swimmer comprises a fin which influences the
orientation of the swimmer body in the horizontal plane when the
device is in the wave-bearing water, e.g. one or more fins which
are substantially vertical when the device is in still water, for
example one or more such fins secured to, or being an integral part
of, the swimmer body; for example, a part of the swimmer body could
have a relatively small horizontal dimension and a relatively large
vertical dimension; for example, such a part, if it formed the
trailing end of the swimmer body could be actuated to steer the
swimmer;
[0030] (J) the device is a water vehicle which moves in a
horizontal direction when the device is in wave-bearing water;
[0031] (K) the swimmer body comprises a central tubular housing and
wave-actuated propulsion fins extend either side of the body
tube;
[0032] (L) the swimmer body comprises a generally tubular housing
and vertical fin surfaces at or near both the leading end and the
trailing end of the swimmer body; one or both of such vertical fin
surfaces can optionally be actuated to steer the vehicle;
preferably the trailing fin can be actuated to steer the swimmer,
and the leading fin is fixed; the two fins help to balance the drag
forces and to limit rotation of the swimmer when it is pulled
sideways by the tether.
[0033] When reference is made herein to a fin or other component
which rotates about an axis of rotation, or to a component which is
rotatably mounted or secured, this includes not only the
possibility that the rotation is about a single axis, but also the
possibility that the rotation results from rotation about two or
more adjacent axes (which may be, but need not be, parallel to each
other), and the possibility that the rotation involves a continuous
relative motion of adjacent parts of the fin or other component, as
for example when one part of a flexible fin is fixed and the rest
of the flexible fin moves relative to (i.e. "rotates about") the
fixed part.
[0034] Other novel characteristics which are optionally present are
described below.
[0035] A device having characteristics (A) and (B) can for example
include (i) a generally laminar fin which is mounted, optionally
rotatably mounted, directly or indirectly on a rigid bar which is
mounted, optionally rotationally mounted, on the swimmer body, and
(ii) a spring and/or a torsion bar which is directly or indirectly
connected to the fin and/or to the rigid bar and which influences
(a) the speed and/or the extent of the rotation of the fin and/or
the rigid bar, and/or (b) the spatial relationship between the
swimmer body and the axis of rotation, during part or all of the
changes in configuration of the system.
[0036] A device having characteristic (C) can for example have a
fin system which comprises a generally laminar and elastically
deformable fin (such a fin optionally being the sole elastic
component, or one of a plurality of elastic components, of the fin
system), the fin having a leading edge which comprises (i) a
relatively rigid central section which rotates about an axis of
rotation generally transverse to the longitudinal axis of the
swimmer body, and (ii) relatively deformable outboard sections (for
example a fin having a swept back, e.g. generally V-shaped, leading
edge),
[0037] In a second preferred aspect, this invention provides a
wave-powered water vehicle which comprises [0038] (1) a float,
[0039] (2) a swimmer, [0040] (3) a tether connecting the float and
the swimmer, and [0041] (4) a computer system; the float, swimmer
and tether being such that, when the vehicle is in still water,
[0042] (i) the float is on or near the surface of the water, [0043]
(ii) the swimmer is submerged below the float, and [0044] (iii) the
tether is under tension; the swimmer, when the vehicle is in
wave-bearing water, interacting with the water to generate forces
which move the vehicle in a horizontal direction; the float
comprising a satellite-referenced position sensor; the swimmer
comprising (a) a sensor which senses direction in a horizontal
plane, and (b) a steering actuator; and the computer system (a)
being linked to the position sensor, the horizontal sensor and the
rudder, and (b) containing, or being programmable to contain,
instructions to control the steering actuator in response to
signals received from the position sensor and the horizontal
sensor, or in response to signals received from a sensor on the
vehicle. In the water vehicles of the second aspect of the
invention, the swimmer preferably comprises a body and a fin system
according to the first aspect of the invention, but can comprise a
different means for generating forces which move the vehicle in a
horizontal direction.
[0045] The invention will be chiefly described by reference to
water vehicles in which at least part of the useful power generated
by the movement of the swimmer is used to move the vehicle in a
horizontal direction (the remainder of that power, if any, being
converted into other useful forms, or wasted). However, the
invention includes the possibility that none of the power generated
by the movement of the swimmer is so used, i.e. all that power is
converted into other useful forms or is wasted, as for example when
the float or the swimmer is held in a fixed location, e.g. by an
anchor or other attachment.
[0046] If the float is also moved by other forces (for example by
wind, water currents or a conventional propulsion system) the
movement of the swimmer modifies (for example accelerates or
decelerates and/or changes the direction of) the movement of the
float.
[0047] The water vehicles of the invention often comprise a single
float and a single swimmer, and the invention will be chiefly
described with reference to such water vehicles. However, the
invention includes the possibility that there is more than one
float, and/or more than one swimmer, for example a single float
attached to a plurality of swimmers, the swimmers preferably being
axially aligned, by a plurality of tethers.
[0048] For any particular water vehicle of the invention, the
influence of the swimmer on the movement of the float will depend
on the size and frequency of waves. The movement of the float will
also depend for example on environmental conditions such as water
currents and wind, and any other propulsion or steering system
operating on the float. In suitable conditions, the swimmer will
move the vehicle forward at a speed which is satisfactory for many
purposes, without any other propulsion system (though it may be
desirable to use another power source to operate a steering
system). In preferred embodiments, the vehicle is equipped with
control and steering systems which enable it to be remotely
controlled in a desired way, for example so as to move in a closed
pattern around a desired fixed location, and/or to follow a desired
path between two locations, which may be many miles apart, and/or
to traverse slowly back and forth over an area of the ocean in
order to gather a wide variety of data.
[0049] In a third preferred aspect, this invention provides a
method of utilizing wave power which comprises placing a device
according to the first or second preferred aspect of the invention
in a body of water which has or which is expected to have water
waves traveling across its surface.
[0050] In a fourth preferred aspect, this invention provides a
method of obtaining information which comprises receiving signals
from a device according to the first or second preferred aspect of
the invention.
[0051] In a fifth preferred aspect, this invention provides a
method of obtaining information which comprises examining signals
recorded by a device according to the first or second preferred
aspect of the invention.
[0052] In a sixth preferred aspect, this invention provides a
method for controlling a function of a device according to the
first or second preferred aspect of the invention, the method
comprising sending signals to the device.
[0053] In a seventh preferred aspect, this invention provides novel
floats suitable for use in the first or second preferred aspect of
the invention and for other purposes; novel swimmers suitable for
use in the first or second preferred aspect of the invention and
for other purposes; novel fin systems suitable for use in the first
or second preferred aspect of the invention and for other purposes;
and novel fins suitable for use in the first and second preferred
aspects of the invention and for other purposes.
[0054] In an eighth preferred aspect, this invention provides kits
of parts comprising two or more of the components needed to
assemble a device according to the first or second preferred aspect
of the invention.
[0055] Other novel features are disclosed in the Detailed
Description below and the attached Drawings, and form part of the
present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The invention is illustrated by the accompanying drawings,
which are diagrammatic and not to scale, and in which
[0057] FIG. 1 is a diagram of a water vehicle,
[0058] FIGS. 2 and 3 are cross-sections of fins for use in certain
embodiments,
[0059] FIG. 4 is a cross-section of a tether,
[0060] FIG. 5 is a block diagram of a control system,
[0061] FIG. 6 shows a path for a station-keeping water vehicle,
[0062] FIG. 7 is a perspective view of a water vehicle,
[0063] FIG. 8 shows different configurations of a fin in FIG.
7,
[0064] FIG. 9 is a perspective view of a water vehicle, and
[0065] FIG. 10 is an enlarged perspective view of part of FIG.
9,
[0066] FIGS. 11A to 11D show different configurations of the fins
in FIG. 9,
[0067] FIGS. 12-19 and 21 are side views of water vehicles, and
FIG. 20 is a plan view of the water vehicle of FIG. 21,
[0068] FIGS. 22A to 22C show different configurations of a water
vehicle having a flexible body, and
[0069] FIGS. 23-25 are perspective views of water vehicles.
[0070] In some Figures the shape of the fin system is not numbered.
In others, the fin system is numbered 0, 1, 2, 3 or 4. If the
configuration is numbered 0, it is the configuration when the
vehicle is in still water. If the configuration is numbered 1, it
is the configuration likely to be adopted when float is falling
behind the wave crest, and the tension on the tether is falling
(and may be zero). If the configuration is numbered 2, it is the
configuration likely to be adopted when the float has fallen to the
trough of the wave, and the tension on the tether starts to
increase. If the configuration is numbered 3, it is the
configuration likely to be adopted when the float is rising towards
the top of a wave and the tether is at or close to its maximum
tension for this particular cycle. If the configuration is numbered
4, it is the configuration likely to be adopted when the float is
near the top of a wave crest and the tension on the tether has
decreased.
DETAILED DESCRIPTION OF THE INVENTION
[0071] In the Summary of the Invention above, the Detailed
Description of the Invention below, and the accompanying drawings,
reference is made to particular features of the invention. It is to
be understood that the disclosure of the invention in this
specification includes all possible combinations of such particular
features. For example, where a particular feature is disclosed in
the context of a particular aspect, a particular embodiment, or a
particular Figure, that feature can also be used, to the extent
appropriate, in the context of other particular aspects,
embodiments and Figures, and in the invention generally. It is also
to be understood that this invention includes all novel features
disclosed herein and is not limited to the preferred aspects of the
invention set out above.
[0072] The term "comprises" and grammatical equivalents thereof are
used herein to mean that other elements (i.e. components,
ingredients, steps etc.) are optionally present. For example, a
water vehicle "comprising" (or "which comprises") components A, B
and C can contain only components A, B and C, or can contain not
only components A, B and C but also one or more other components.
The term "at least" followed by a number is used herein to denote
the start of a range beginning with that number (which may be a
range having an upper limit or no upper limit, depending on the
variable being defined). For example "at least 1" means 1 or more
than 1, and "at least 80%" means 80% or more than 80%. The term "at
most" followed by a number is used herein to denote the end of a
range ending with that number (which may be a range having 1 or 0
as its lower limit, or a range having no lower limit, depending
upon the variable being defined). For example, "at most 4" means 4
or less than 4, and "at most 40%" means 40% or less than 40%. When,
in this specification, a range is given as "(a first number) to (a
second number)" or "(a first number)-(a second number)", this means
a range whose lower limit is the first number and whose upper limit
is the second number. For example, "from 5 to 15 feet" or "5-15
feet" means a range whose lower limit is 5 feet and whose upper
limit is 15 feet. The terms "plural", "multiple", "plurality" and
"multiplicity" are used herein to denote two or more than two
items.
[0073] Where reference is made herein to a method comprising two or
more defined steps, the defined steps can be carried out in any
order or simultaneously (except where the context excludes that
possibility), and the method can optionally include one or more
other steps which are carried out before any of the defined steps,
between two of the defined steps, or after all the defined steps
(except where the context excludes that possibility). Where
reference is made herein to "first" and "second" elements, this is
generally done for identification purposes; unless the context
requires otherwise, the first and second elements can be the same
or different, and reference to a first element does not mean that a
second element is necessarily present (though it may be present).
Where reference is made herein to "a" or "an" element, this does
not exclude the possibility that there are two or more such
elements (except where the context excludes that possibility). For
example, where reference is made herein to a fin, or a fin system,
the swimmer can (and frequently does) comprise two or more fins or
fin systems, which may be the same or different. Where reference is
made herein to two or more elements, this does not exclude the
possibility that the two or more elements are replaced by a lesser
number or greater number of elements providing the same function
(except where the context excludes that possibility). For example,
the swimmer body and the fin system can together form a single
unitary body. The numbers given herein should be construed with the
latitude appropriate to their context and expression; for example,
each number is subject to variation which depends on the accuracy
with which it can be measured by methods conventionally used by
those skilled in the art.
[0074] Unless otherwise noted, the references to the positioning
and shape of a component of the vehicle refer to that positioning
and shape when the vehicle is in still water. Various terms are
used in this specification in accordance with the definitions given
above and the further definitions given below.
[0075] "Leading edge" (or leading end) and "trailing edge" (or
trailing end) denote the front and rear surfaces respectively of a
fin or other component as wave power causes the vehicle to move
forward.
[0076] "Fore" and "aft" denote locations relatively near the
leading and trailing edges (or ends) respectively.
[0077] "Aligned" denotes a direction which lies generally in a
vertical plane which is parallel to the vertical plane which
includes the longitudinal axis of the swimmer. "Axially aligned"
denotes a direction which lies generally in the vertical plane
which includes the longitudinal axis of the swimmer.
[0078] "Transverse" denotes a direction which lies generally in a
vertical plane orthogonal to the vertical plane which includes the
axial centerline of the swimmer.
[0079] Where reference is made herein to a feature which
"generally" complies with a particular definition, for example
"generally in a vertical plane", "generally laminar", or "generally
horizontal", it is to be understood that the feature need not
comply strictly with that particular definition, but rather can
depart from that strict definition by an amount which permits
effective operation in accordance with the principles of the
invention.
[0080] All the components of the vehicle are preferably constructed
of materials which are resistant to salt water, or enclosed within
a watertight jacket of such material, particularly any electrical
connections. Preferably, the materials which are exposed to the
water are resistant to bio-fouling, and are unattractive or even
repellent to marine animals, like sharks. Suitable materials can
for example be selected from metals and polymeric compositions,
including copper-containing paints and low surface energy polymers
such as polytetrafluoroethylene. When the vehicle includes
batteries and solar panels (or other electricity-generating means),
bio-fouling can also be discouraged by using the power from the
batteries or solar panels to briefly electrify conductive materials
on the vehicle, and/or to energize a vibrator which will dislodge
bio-fouling materials. Leading edges which may be snagged by
seaweed can optionally have sharp or serrated edges.
[0081] The vehicle is preferably designed to minimize drag as
movement of the swimmer pulls it forward, and to minimize the
effect of winds and water currents which move the vehicle sideways.
The float or the swimmer or both can have flaps which are folded-in
and have little effect on drag when the float or swimmer is moving
forward, but which fan out and increase drag when the float or
swimmer is moving backwards. Such flaps are preferably positioned
so that they keep the float and/or the swimmer in a desired
orientation if it moves backwards.
The Swimmer Body
[0082] The swimmer body preferably has a generally cylindrical
shape, or other shape selected to minimize drag as the fin system
pulls the swimmer body through the water. Often there is a single
body, but there can be a plurality of bodies secured to each other,
preferably rigidly, with their axes aligned, or with their axes
parallel to, and spaced-apart from, each other. Preferably the body
has a longitudinal axis which is generally horizontal when the
vehicle is in still water.
[0083] The length of the swimmer body can for example be at least 1
foot, e.g. 3 to 10 or 4 to 6 feet, but can be substantially
greater, e.g. up to 1000 feet or more. The diameter (or, for
non-cylindrical bodies, each of the minimum and maximum transverse
dimensions) of the swimmer can for example be at least 0.1 feet, or
at least 0.3 feet, up to, for example, 0.1 times the length of the
swimmer.
[0084] In some embodiments the entire swimmer body will be rigid.
However, it is also possible for part of the swimmer body to be
elastically deformable. For example, the swimmer body can have a
central section which is flexible, preferably substantially only in
the vertical plane, with the rudder mounted on a rigid section aft
of the flexible central section and the fin system mounted on a
rigid section forward of the flexible central section. Optionally,
the swimmer has a center of buoyancy which is above the center of
gravity.
[0085] As further discussed below, a wide variety of additional
components can be attached to the swimmer body. Heavy components
are preferably secured to the swimmer rather than to the float. The
wet weight of the swimmer, including the components attached
thereto, can for example be 5-20,000 lbs, e.g. 5-500 lbs, for
example 20-60 lbs. Many components are preferably placed within a
watertight enclosure provided by the swimmer body (for example
electrical equipment, including batteries, electronic equipment,
servo mechanisms, watertight pass-throughs, and direction-finding
equipment). Others are preferably or necessarily placed outside the
swimmer body, for example stabilizer fins, stabilizer weights,
rudders, some types of sensor, and sample collectors. Stabilizer
fins, which can for example be placed near the front and/or near
the rear of the swimmer body, can for example be generally vertical
fixed and aligned fins which resist transverse drag on the swimmer,
or generally horizontal fixed and aligned fins which resist
vertical drag on the swimmer. Stabilizer weights can for example be
bars and/or discs, usually aligned with the swimmer body, fixed to
struts descending vertically from the swimmer body, thus increasing
the weight and changing the center of gravity of the swimmer, or
can be part of a keel-like vertical stabilizer fin.
[0086] In one embodiment, a hydrophone is secured to the swimmer
body. Preferably, in order to separate the hydrophone from noise
generated by the swimmer, the hydrophone is placed at the end of a
cable dragged behind the swimmer body, or on an extension bar
projecting from, e.g. from the front of, the swimmer body.
The Float
[0087] The float can be of any convenient size and shape, bearing
in mind the components which it carries, the way in which it will
be used, and the desirability of minimizing drag in the water and
against wind. The length of the float can be less than, e.g. 0.5 to
0.9 times, substantially equal to, e.g. 0.9 to 1.1 times, or
greater than, e.g. 1.1 to 4 times, the length of the swimmer. The
length of the float can for example be at least 1 foot, e.g. 3 to
10 or 4 to 6 feet, but can be substantially greater, e.g. up to
1000 feet or more, so long as it is not too large to be
substantially moved by waves. The breadth of the float can for
example be at least 0.3 foot, or at least 2 feet, up to, for
example, 0.3 times the length of the float. Optionally, the float
has a center of buoyancy which is above the center of gravity. The
float can for example have 20-500 lbs, e.g. about 80 lbs, of
buoyancy, and/or a buoyancy which is 2-4 times the wet weight of
the swimmer.
[0088] To reduce the danger that wind, waves or current forces push
the float sideways, preferably both the center of water drag and
the center of wind drag are behind the line attachment point, since
this helps to keep the float in a head-on orientation in which it
has the lowest overall drag. Wind and water forces acting on the
parts of the float forward of the tether attachment point tend to
rotate the float away from the desired orientation, whereas those
aft of the attachment point tend to produce the desired
orientation. Therefore, the nose of the float is preferably is
relatively blunt and truncated, whereas the tail portion of the
float preferably has an extended tail portion with greater vertical
surface area.
[0089] The float may include a rudder. The rudder may be fixed
during some or all of the operation of the vehicle, in order to
keep the center of drag behind the tether attachment point. The
rudder may also be adjustable, in order to assist steering of the
vehicle; in this case, the tether is preferably attached to the
swimmer in front of the swimmer's center of drag. Especially when
the tether is attached slightly forward of the center of buoyancy
of the float, the submerged surfaces of the float may be shaped so
as to produce forward thrust.
[0090] The float optionally comprises an outer shell comprising a
polymeric composition, e.g. a fiberglass- or carbon
fiber-reinforced polymeric composition, and/or a thick-walled
elastomeric sheet material. The shell can optionally surround a
closed cell polymeric foam core, e.g. a compliant closed cell foam,
and/or a plurality of hollow cavities. In some embodiments, such
cavities can optionally be inflatable (for example being composed
of an elastomeric material), so that they can be partially or
completely filled with water and/or air to control buoyancy.
The Tether
[0091] The tether connects the float and the swimmer mechanically,
and for this purpose comprises a tensile member of suitable
breaking strength, e.g. at least 500 or at least 1500 lb; the
tensile member can for example be composed of a metal, e.g.
stainless steel, and/or a polymeric composition, e.g. Kevlar or
Spectra. Often, the tether also comprises one or more members which
do not carry any load and which transmit electrical power and/or
data, e.g. one or more twisted pairs of insulated electrical
conductors, optical fibers or acoustic cables. Generally, the
tether will support only tensile loads, but the invention includes
the possibility that the tether will also resist compression, e.g.
is a rod.
[0092] To reduce drag, the components of the tether are preferably
arranged to minimize the area of the leading edge of the tether,
with the primary tensile member at the front, and the tether
optionally includes a jacket, preferably of streamlined
cross-section, e.g. composed of a polymeric composition, e.g. a
composition based on a silicone or vinyl chloride polymer, which
surrounds the other components. Twisting of the tether increases
drag, and optionally measures can be taken to reduce twisting. For
example, a second tensile member can be present at the trailing
edge of the tether, and/or the vehicle can include a device to
detect and correct twisting of the tether, and/or the vehicle can
be directed along a path in which the clockwise and anticlockwise
turns are balanced (in particular, when the vehicle is directed
along a path surrounding a fixed point).
[0093] The tether can for example have an aligned dimension of 0.5
to 1.0 inch, e.g. about 0.625 inch, a transverse dimension of 0.125
to 0.5 inch, e.g. about 0.19 inch, and a length of for example 10
to 80 feet, e.g. 17 to 23 feet. Either the float or the swimmer can
include a reel or other equipment which makes it possible to change
the length of the tether, either to suit particular wave conditions
and/or water depth, and/or to make the vehicle more easily stored,
carried and deployed.
[0094] The tether can for example include an elastomeric member,
e.g. a spring, which changes in length reversibly when the relative
positions of the float and swimmer change, for example in one leg
of a tether generally shaped as an inverted Y.
[0095] In some embodiments, there is a single tether. The tether
can for example have a central section which is a single line, and
a lower section (attached to the swimmer) and/or an upper
section(attached to the float) which has two or more legs, secured
to fore and aft positions, or to transverse positions, on the
swimmer or the float. In one embodiment, the tether has the shape
of an inverted Y, the lower legs of the Y being (a) aligned with,
and secured to fore and aft positions on, the swimmer, or (b)
transverse to the swimmer and secured to components extending
transversely from the axis of the swimmer.
[0096] When there is a single tether between the swimmer and the
float, its configuration and point of attachment (or points of
attachment, if the tether has two or more lower legs) to the
swimmer are preferably such that the upward force exerted on the
swimmer, when the tether is pulled upwards, passes through the
swimmer at or close to the center of gravity of the swimmer. The
swimmer is then substantially horizontal when the vehicle is in
still water. This assists the swimmer to maintain a level
orientation.
[0097] When there is a single tether between the swimmer and the
float, its configuration and point of attachment (or points of
attachment, if the tether has two or more upper legs) to the float
are preferably such that the downward force exerted on the float,
when the tether is pulled upwards, passes through the float near,
or slightly forward of, the center of buoyancy of the float.
[0098] In other embodiments, there are multiple tethers, for
example first and second tethers respectively attached to fore and
aft positions on the float and the swimmer. Multiple tethers
increase drag, but reduce twisting.
[0099] The tension force of the tether stabilizes both the swimmer
and the float. While each element may also be independently
stabilized by positioning of the center of floatation above the
center of gravity, this is not necessary. The fact that the line
tension stabilizes both the swimmer and float simplifies the
control of the vehicle. In some embodiments, the vehicle only needs
to be steered in one degree of freedom, and other attitude control
is passively stabilized, making it unnecessary for the vehicle to
include attitude control thrusters or flaps (although such
thrusters and flaps can be present on the vehicles of the
invention).
The Fin Systems
[0100] When the swimmer is being moved by wave power, the
configuration of the fin system changes in cycles corresponding to
the waves on the surface of the water. Generally, but not
necessarily, the changes in the configuration in each cycle are
substantially the same. The changes in the configuration in each
cycle are generally substantially continuous, but can be
discontinuous (i.e. there can be one or more periods in each cycle
during which the configuration remains the same). During at least
part of the cycle, the fin system interacts with the water to
generate forces which thrust the swimmer in a horizontal direction.
In some embodiments, the fin system comprises a fin which rotates
about a transverse axis. In other embodiments, the fin system
comprises a pair of fins which rotate about a longitudinal axis. In
either case, as the swimmer rises and falls, the fin or fins can
optionally undergo elastic distortion which enhances the forward
thrust of the swimmer.
[0101] Various wave sizes will produce various motion amplitudes.
With relatively large amplitude motions, the majority of the thrust
will be produced during the upward and downward phases of fin
motion. With relatively small amplitude motions these phases may be
brief and a majority of thrust can be produced through the rotation
of the fin structures. Flexible fins can produce thrust from both
small amplitude motion and from large.
[0102] Different fin systems which interact with the water in the
desired way include, but are not limited to, the various types
described herein. A particular fin system can make use of
combinations of two or more of these types, except when they are
incompatible with each other; and a water vehicle can comprise two
or more fin systems of the same or different types or combinations
of types. Where reference is made below to a "generally laminar
fin", this includes the possibility that the thickness of the fin
changes, regularly or irregularly, in the transverse direction or
in the aligned direction, or both, and the possibility that parts
of the fin extend outwards from its generally laminar shape. Where
reference is made below to a generally laminar fin which "lies in a
generally horizontal plane", this includes the possibility that
principal plane of the fin lies in a plane which is inclined to the
horizontal at an angle which permits effective operation of the
fin, for example at an angle which is not more than 45.degree.,
preferably not more than 20.degree., to the horizontal.
[0103] In some embodiments of the invention, part or all of the fin
system has a first configuration when the vehicle is in still
water; is converted from the first configuration into a second
configuration when the swimmer is pulled upwards by the tether as a
result of a wavecrest lifting the float upwards; and is converted
from the second configuration into a third configuration when the
swimmer sinks downwards as a result of a wavetrough allowing the
float to descend. The third configuration will generally be
different from the first configuration, but the invention includes
the possibility that it is the same as the first configuration.
When the fin system is converted from the second configuration to
the third configuration, it can, but need not, pass through the
first configuration as a transitory state. The fin system can for
example comprise one or more fins comprising generally laminar
portions which deform elastically between the different
configurations. Alternatively or additionally, the fin system can
for example comprise one or more elastically deformable components,
which change shape between the different configurations, and thus
control, or help to control, the movement of fin or fins comprising
generally laminar portions. The elastically deformable component
can control, or help to control, the movement of a fin in one
direction only (e.g. a spring) or in both the upward and downward
direction (e.g. a torsion bar).
[0104] Limit stops may be included to prevent overstressing of a
flexure. The stop may be a rigid stop, an elastic stop, e.g. a
spring, or an increasing rate spring may be used for the
flexure.
[0105] The fin system comprises at least one fin, the fin
preferably having one or more of the following characteristics:
[0106] (a) it is at least in part elastically deformable;
[0107] (b) it comprises a leading portion which is relatively rigid
and a central portion and/or a trailing portion which is relatively
and elastically deformable;
[0108] (c) it comprises a leading portion which is relatively and
elastically deformable, a central portion which is relatively
rigid, and a trailing portion which is relatively and elastically
deformable;
[0109] (d) it has a shape similar to the shape of the tail of a
fish or a whale;
[0110] (e) in the first configuration, it is generally planar in a
generally horizontal plane; and
[0111] (f) in the second configuration, it is generally laminar and
downwardly curving, the second configuration being a result of
flexing and/or rotating the fin about an axis which lies in a plane
which is generally orthogonal to the tether and generally at right
angles to the longitudinal axis of the swimmer; and
[0112] (g) when the swimmer sinks downwards as a result of a
wavetrough causing the float to fall, the fin system changes from
the second configuration to the third configuration, the third
configuration being generally laminar and upwardly curving.
[0113] Other optional features of the fin system include;
[0114] (1) the fin system comprises a plurality of fins mounted to
a frame, for example a plurality of fins mounted to both sides of a
spine, or a plurality of fins mounted between side rails;
[0115] (2) the fin system comprises a pair of fins, the fins [0116]
(i) extending away from opposite sides of the swimmer body, [0117]
(ii) being secured to the swimmer body so that they can move
between the first and second configurations, the position of the
fins in the second configuration extending upwards relative to the
position of the fins in the first configuration, and [0118] (iv)
being biased by a spring or other elastic recovery means into the
first configuration and away from the second configuration;
[0119] (3) the fin system comprises a pair of fins and the tether
comprises an inverted V-shaped section having two legs, each leg
being secured to one of the fins; and
[0120] (4) the fin system comprises a caudal fin;
[0121] In the first aspect of the invention, the fin system
optionally comprises at least one additional member whose shape is
fixed and is such that that the additional member directly or
indirectly generates desired forces as the swimmer is moved by the
movement of the float. In one embodiment of the second aspect of
the invention, such members are the sole means for generating the
desired forces.
[0122] The optimum amount of flexibility for a flexible fin will
depend on many characteristics of the design and of the wave
characteristics anticipated. If the fin is too flexible, then the
curvature during the large amplitude motion may be so large that
the trailing portion of the fin may flex to be parallel to the
direction of motion and thus generate little thrust. If the fin is
too rigid, then the fin will not flex with any inflections and
small amplitude inputs will not efficiently generate thrust.
[0123] The fin system often includes a rigid component which is
secured to, preferably positioned above, the body of the swimmer.
The rigid component can for example have one or more of the
following characteristics.
[0124] (i) it is rigidly fixed to the body portion,
[0125] (ii) it is positioned above the body portion and a unitary
tether, or one leg of a tether having an inverted Y configuration,
is secured thereto,
[0126] (iii) at least one fin system is secured thereto, the fin
systems, when there is more than one fin system, being mounted one
above the other and/or beside each other,
[0127] (iv) it is the first component of a support system which
also comprises a second rigid component; the first component being
positioned above, and secured directly to, the body portion in a
generally vertical plane when the vehicle is in still water, and
the second component being secured directly to the first component
and having one or more fin systems secured thereto; the second
component optionally being secured to the first component so that
the second component can be rotated relative to the first component
in a generally vertical plane; and the rotation optionally being
influenced by an elastically recoverable member, e.g. a spring or a
torsion bar; and at least part of the tether optionally being
secured to the second component so that upward pulling of the
tether distorts the elastically recoverable member, the extent of
rotation optionally being further limited by an inextensible
member;
[0128] In some embodiments, a generally planar fin or a pair of
generally planar fins undergoes elastic deformation in the
transverse direction (and may also undergo elastic deformation in
the aligned direction). In some cases, such fins can move
vertically without substantial vertical motion of the swimmer body.
They flap in a manner similar to the pectoral fins on a fish, or
the wings on a bird. Preferably the fin or fins rotate about an
axially aligned longitudinal axis. Optionally, the fin surfaces can
also rotate and/or flex relative to the horizontal plane or
relative to a plane that intersects the longitudinal axis and an
axis through the wing spar.
[0129] Pectoral fins of this kind are preferably directly actuated
by the tether, thus reducing motion of the swimmer body. In some
cases, this makes them well suited for large swimmers or for
applications where the swimmer body should be held relatively
steady.
[0130] By attaching the legs of the tether to different points
along the length of the pectoral fins, the amount of fin motion
relative to the amount of line motion may be adjusted.
[0131] Pectoral fins may for example have an internal skeletal
structure made of a less flexible, optionally substantially rigid,
material with high fatigue life such as tempered steel or carbon
fiber composite. The skeletal structure can include a front spar
that makes the leading edge relatively rigid. The primary flexion
of the skeletal structure occurs in vertical bending of the front
spar near the attachment to the body. The rigidity of the front
spar may increase toward the outer parts to prevent the wing tips
from drooping. The trailing edge of the wing can for example be
comprised only of the elastomer jacket material and be relatively
flexible.
[0132] The tether is preferably attached to the wing skeletal
structure at two points, one on each wing. The wing structure is
preferably such that when the tether is not under tension, the fin
flexes downward; and when the vehicle is in still water, the fins
flex to a relatively flat position. Increased line tension will
cause the wings to flex upward.
[0133] The line attachment points are preferably toward the front
edge of the wings. The center of gravity (COG) is preferably under
the line junction point so that the swimmer body is horizontal in
still water. If there is more fin area behind the line attachment,
upward motion will cause the swimmer to pitch nose up. If there is
more fin area is behind the COG, downward motion will cause the
swimmer to pitch nose down. Optionally, a rudder steers the
swimmer. Optional features of swimmers of this type can
include:
[0134] (a) A smooth outer body which has no exposed mechanism and
is resistant to fouling.
[0135] (b) Flexion distributed over a large area so that fatigue at
specific points can be minimized for long life.
[0136] (c) A streamlined overall shape which enables increased
speed.
[0137] (d) Sudden increases in tether tension are transmitted
immediately to fins so that the inertia of the vehicle does not
impeded conversion to thrust.
[0138] (e) The tips of the fins extend beyond the line attachment
points and the wing spar is relatively rigid in this region, so
that the tips of the fins move through a larger amplitude than the
tether. This helps generate large amounts of thrust from small
amounts of tether motion.
Additional Components
[0139] Additional components which can be part of the vehicle
include, but are not limited to, the following. Some components,
e.g. electronic control equipment, can be part of either or both of
the float and the swimmer. Bulky or massive items, e.g. batteries,
and equipment that operates best with limited motion and/or when
protected from wind and noise, such as imaging or mapping
equipment, and hydrophones and sonar equipment, are preferably part
of the swimmer. Other components, e.g. solar collection means,
radio and navigation antenna, beacons and weather sensors are
preferably part of the float.
[0140] Examples of additional components include, but are not
limited to, the components set out in paragraphs 1-14 below.
[0141] (1) Communications equipment for sending and/or receiving
data, e.g. digital or analog radio signals, for example
communications equipment for [0142] (i) sending signals which
reflect data collected by a monitoring or sensing device which is
part of the vehicle; [0143] (ii) receiving signals, e.g. commands,
from a base station (e.g. a ship or a ground station) or from
navigation devices, for example satellite navigation equipment such
as a global positioning satellite (GPS), or sonar or radio buoys,
[0144] (iii) sending signals to a receiving station, for example
via a satellite, [0145] (iv) sending signals which are influenced
by the location of the vehicle.
[0146] (2) Recording equipment for recording signals, e.g. digital
or analog signals, for example signals which are [0147] (i)
influenced by signals from a satellite navigation system, e.g. GPS;
[0148] (ii) sent from the vehicle to a receiving station, for
example via a satellite; [0149] (iii) influenced by the location of
the vehicle; or [0150] (iv) influenced by a sensor which is part of
the vehicle, e.g. a hydrophone attached to the swimmer;
[0151] (3) Control electronics for controlling equipment forming
part of the vehicle.
[0152] (4) Steering means, for example a rudder forming part of the
float and/or a rudder forming part of the swimmer, the steering
means being for example a fixed rudder on the float (e.g. to keep
the center of drag behind the point at which the tether is attached
to the float), and/or a rudder or other steering means which is
attached to the swimmer and which includes a rudder actuator
responsive to signals generated within the vehicle, e.g. from a
magnetic compass or a gyroscope, and/or received by communications
equipment forming part of the vehicle.
[0153] (5) Electrical power sources, for example batteries or fuel
cells, preferably power sources that can be recharged, for example
by output from solar cells mounted on the float. Batteries, because
they are heavy, are preferably placed within the container body of
the swimmer. There can be, for example, four to ten 6 volt lead
acid batteries.
[0154] (6) Means for utilizing solar energy, e.g. solar panels or
solar cells mounted on the float.
[0155] (7) A sensor, this term being used to denote any device
which reports, or responds to a change in, any observable
condition. Thus the sensor can be any one of a large variety of
scientific or surveillance devices, for example a compass, a
gyroscope, a temperature sensor, a pressure sensor, a sensor of any
type of electromagnetic radiation, e.g. visible, ultraviolet or
infrared light, a chemical sensor, e.g. a salinity sensor, a
magnetometer, a biological sensor, a geological sensor, a water
current sensor, a depth sensor, a speedometer, equipment for
imaging the sea floor, a sensor of weather or other climatic
changes, e.g. windspeed, rainfall, or barometric pressure, or a
hydrophone (for example a hydrophone for monitoring the sounds made
by whales or other aquatic life).
[0156] In some embodiments, because the vehicles of the invention
do not need to include conventional propulsion components, or other
noisy components, they provide excellent platforms for
noise-sensitive devices and do not have any adverse effect on
noise-sensitive devices carried by other equipment, e.g. other
water vehicles.
[0157] (8) Auxiliary propulsion means, e.g. a motor-driven
thruster.
[0158] (9) Auxiliary attitude control means, e.g. flaps.
[0159] (10) Means for reversibly altering the buoyancy of the
float. Such means include, for example, chambers which can be
inflated with air to increase buoyancy and deflated to reduce
buoyancy, and/or chambers which can be filled with water to
decrease buoyancy and evacuated to increase buoyancy. In this way,
the float can be maintained at a desired level in the water
(including submerged). Reducing buoyancy is valuable, for example,
when adverse weather conditions might endanger the vehicle,
particularly if the vehicle is relatively small. Such chambers can
for example comprise valves, e.g. one-way valves, which are
controlled by computers responding to input from sensors on the
vehicle itself or from radio signals. The energy needed to inflate
and/or to evacuate such chambers can be derived directly from waves
striking the float, and/or from the wave power generated by the
relative movement of the float and the swimmer, and/or from stored
electrical power. For example, a chamber can comprise a flexible
portion which will act as a pump when struck by waves, and which
will either fill or empty the chamber, depending upon the position
of the valves. Alternatively or additionally, the float can
comprise one or more chambers with the one or more inlets through
which water can enter when waves are high but not when waves are
low, and one or more outlets from which the water can drain when
waves are low.
[0160] (11) Equipment for collecting samples, for example samples
of water, air, aquatic organisms, sea animals, vegetables or
minerals.
[0161] (12) Equipment for utilizing wind energy, e.g. to recharge
batteries.
[0162] (13) Auxiliary electrical equipment, for example lights,
beacons, or a motor driving a propeller.
[0163] (14) Means for converting part or all of the movement of the
swimmer into electrical energy.
[0164] In preferred embodiments, it is possible to operate surface
components, e.g. solar cells and/or radio, and a submerged
component simultaneously, so that data transmission can be "real
time". It is also possible to plan alternating phases of data
collection and transmission.
Directing the Vehicle along a Desired Path
[0165] In some uses of the invention, the vehicle is directed along
a desired geographical path by using a computer attached to the
float or the swimmer, or both, the computer being used
[0166] (a) to process (i) input from a magnetic compass or
gyroscope (preferably attached to the swimmer), (ii) input from a
satellite navigation system, e.g. GPS (preferably attached to the
float), and (iii) geographical coordinates preprogrammed into the
computer and/or input to the computer by radio commands; and
[0167] (b) to output commands to (i) a rudder control system which
controls a rudder or rudders on one or both of the float and the
swimmer, preferably on the swimmer, and (ii), if the vehicle has
auxiliary control or propulsion means, to those means. The input to
the computer can include data available from other sources, e.g. to
take account of winds and currents.
[0168] In other uses of the invention, the vehicle is directed
along a path which is determined by using a computer attached to
the float or the swimmer, or both, the computer being used to
[0169] (a) process input from a sensor attached to the vehicle
itself, or from a network of vehicles, one or more of which are
vehicles of the invention, and
[0170] (b) output commands to (i) a rudder control system which
controls a rudder or rudders on one or both of the float and the
swimmer, preferably on the swimmer, and (ii), if the vehicle has
auxiliary control or propulsion means, to those means.
In this way, for example, a hydrophone, magnetometer or other
sensor on the vehicle could identify the presence of an object in
or on the water or on the seabed, e.g. a ship or other floating or
submerged object, or a whale or other sea creature, and the vehicle
could be directed to follow a path related to that object, e.g. to
track the movement or presence of that object.
[0171] The operation of the vehicle can be controlled by signals
sent to it from a remote control station and/or by signals
generated by the vehicle itself, optionally in conjunction with one
or more preprogrammed command structures forming part of the
vehicle itself.
Station-Keeping
[0172] One way of keeping the vehicle close to a fixed point
("station-keeping") is to direct the vehicle towards the fixed
point at regular intervals, e.g. of 1-10 minutes. If the vehicle
has overshot the fixed point, it turns at the end of the interval.
Successive turns are preferably clockwise and anticlockwise, to
reduce the risk of twisting the tether, and each of the turns is
preferably as small as is consistent with the avoidance of twisting
the tether. Another way is to direct the vehicle along a generally
figure-of-eight path, with the center of the path being the fixed
point, and with the vertical axis of the path aligned with any
ocean current. The vehicle follows a straight line between each of
the turns, and again successive turns are clockwise and
anticlockwise; and, if the time spent outside a zone defined by the
straight sections of the path is important, each of the turns is
preferably as small as is consistent with the avoidance of twisting
the tether.
Speed Control
[0173] In many applications, it is unnecessary to control the speed
of the vehicle. However, if such control is desired, it can for
example be provided by measures such as controlling the angle of
attack of fins, allowing the fins to feather, and holding the fins
stiff, to decrease their efficiency when less thrust is desired. If
there are fins on each side of the swimmer body, these measures can
also be used to steer the swimmer.
The Drawings
[0174] FIG. 1 shows a float 11 is connected to a swimmer 21 by a
tether 31. The float comprises a body 111 on which are mounted
solar panels 112, GPS receiver 113, antennae 114, and electronics
box 115. A rudder 116 is secured to the rear of the float. Tether
31 having an inverted Y shape with lower legs and 311 and 312,
connects the float and the swimmer. The swimmer comprises a body
211 having a nose cone 212. Mounted on the exterior of the body 211
are fin systems 213 and 214. Enclosed within the body 211 are
electrical pass-through 215 for leg 311 of the tether, batteries
216, control electronics 217, rudder servo mechanism 218 and rudder
rod pass-through 219. A rudder 222 is mounted at the rear of the
swimmer body and is controlled by rudder actuation rod 221.
[0175] FIGS. 2 and 3 are cross-sections of fins which can be used
in the present invention. Each comprises a rigid front spar 2131,
which may for example be composed of a sheet metal sandwich
composite and/or have a steel core, a relatively inflexible central
sheet section 2134, which may for example be composed of metal
and/or fiberglass, and a relatively flexible trailing sheet section
2135. In FIG. 3, there is in addition a relatively flexible fore
sheet section 2133, and the flexible trailing sheet is integral
with a flexible outer jacket 2136. The various sections may be
bonded or held together with fasteners such as rivets 2132
[0176] FIG. 4 is a cross-section of a tether 31 which comprises a
tensile member 311, six twisted pairs of insulated electrical
conductors 314, and a streamlined polymeric jacket 315.
[0177] FIG. 5 is a block diagram of a control system for directing
the vehicle along a desired path. Other control systems can be
used.
[0178] FIG. 6 shows a closed generally figure-of-eight path
followed repetitiously by a vehicle to keep it within a target zone
around a fixed point 2 (except when it is turning outside the
zone). The axis of the path is aligned with the ocean current. The
vehicle follows a straight path between points 1 and 3, passing
through point 2. At point 3, control systems on the vehicle note
that the vehicle has reached the perimeter of the target zone, and
operate a rudder so that the vehicle turns anticlockwise between
points 3 and 4. The vehicle then follows a straight path between
points 4 and 5, again passing through point 2. At point 5, the
control systems operate the rudder so that the vehicle turns
clockwise between points 5 and 1. If the vehicle is moved by wind
and/or current in addition to wave power, auxiliary propulsion
means may be needed to maintain the vehicle within the target
zone.
[0179] FIG. 7 is a perspective view of a swimmer 21 and tether 31.
Two substantially identical fin systems, each comprising a rigid
vertical post 226 and a fin 213, are secured to swimmer body 211.
Tether legs 311 and 312 are attached to the tops of the posts 226.
Each fin comprises a relatively rigid front spar 2131 and a
relatively flexible rear section 2135 shaped so that the fin can
operate without striking the swimmer body; the fin optionally
includes one or more intermediate sections (not shown) having
relatively greater or lesser flexibility. A hinge structure 2262 is
bolted to each front spar 2131 and rotates around pivot shafts
secured to the posts 226. Each of four torsion bars 2263 is fixed
at one end to one of the vertical posts and at the other end to a
front spar as a location selected to provide a desired degree of
control over the rotation of the front spar. Each fin can for
example have a cross-section generally as shown in FIG. 2 or FIG.
3. Rigid vertical fins 222 and 223 are secured to the trailing and
leading ends respectively of the swimmer body. Fin 223 is fixed.
Fin 222 can be controlled to rotate about a vertical axis.
[0180] FIG. 8 shows how the shape of the fins in FIG. 7 changes as
the swimmer is pulled up and down by wave motion.
[0181] FIG. 9 is a perspective view of a swimmer 21 and tether 31,
and FIG. 10 is an enlarged perspective view of part of FIG. 9. Two
substantially identical fin systems, each comprising a rigid
vertical post 226 and a fin 213, are secured to swimmer body 211.
Each fin comprises a relatively rigid front spar 2131 and a
relatively flexible rear section 2135 shaped so that the fin can
operate without striking the swimmer body; the fin optionally
includes one or more intermediate sections (not shown) having
relatively greater or lesser flexibility. A hinge bar 2262 is
bolted to each front spar 2131. Bars 2265 are secured to the hinge
bars 2262. One end of each bar 2265 is rotationally secured to a
pivot shaft at the top of one of the posts 226, and the other end
is rotationally secured to longitudinal bar 2266 which joins the
bars 2265 attached to the respective posts. Springs 2267 are
secured to the swimmer body and to the bar 2266. Tether 31 is
secured to the longitudinal bar 2266. Rigid vertical fins 222 and
223 are secured to the trailing and leading ends respectively of
the swimmer body. Fin 223 is fixed. Fin 222 can be controlled to
rotate about a vertical axis. In a similar embodiment (not shown),
the springs are rotationally attached to the bars 2265 instead of
the bar 2266.
[0182] FIGS. 11A to 11D show how the shape of the fins in FIG. 9
changes as the swimmer is pulled up and down by wave motion. In
FIG. 11A, the swimmer is being pulled upwards; the tether tension
increases and pulls the bar 2266 upwards, stretching the springs
2267; the leading edges of the fins rotate downwards, and the
trailing sections of the fins curl upwards, producing thrust from
the bottom surfaces of the fins; and the swimmer body moves
upwards. In FIG. 11B, the tether tension remains high; after the
rotation of the leading edge of the fin reaches its mechanical
limit, and the trailing sections of the fins curl downwards,
producing thrust from the top surface of the fin; the swimmer
continues to rise. In FIG. 11C, the tether tension has decreased;
the springs 2267 pull the bar 2266 downwards; the leading sections
of the fins rotate upwards, and the trailing sections of the fins
curl downwards, producing thrust from the top surfaces of the fins;
and the swimmer moves downwards. In FIG. 11D, the tether tension
remains low; the leading sections of the fins remain rotated
upwards, and the trailing sections of the fins curl upwards,
producing thrust from the bottom surfaces of the fins; and the
swimmer continues to move downwards.
[0183] FIGS. 12-21 show the swimmer of different water vehicles of
the invention. In each, a swimmer 21 has a center of gravity 230
and comprises a swimmer body 211, a nose cone 212 and a rudder 222.
Secured to the swimmer body is a fin system comprising vertical
post(s) 226 and one or more fins, each fin comprising two or more
of flexible inner section 2133, rigid section 2134 and flexible
outer section 2135.
[0184] In FIGS. 12-16, there is a single post, and a tether 31 is
secured to the top of the post. In FIGS. 12-14, the leading edge of
a single fin is fixed to an intermediate position on the post. In
FIGS. 15 and 16, the leading edge of a single fin is rotatably
secured about pivot point 2261 at an intermediate position on the
post. In FIG. 16, stop 2268 limits rotation of the leading edge of
the fin.
[0185] In FIG. 17, there is a single post having a bar 2265
rotatably secured to its top. The leading edge of the fin is
secured to one end of the bar 2265, and tether 31 is secured to the
other end of the bar 2265. Rotation of the bar 2265 is controlled
by spring 2267 secured to the post and the bar. FIG. 18 is similar
to FIG. 17, except that there are three bars 2265 with attached
fins, the tether 31 is secured to the top bar, and a line secured
to the tops of all three bars and to the swimmer body includes the
spring 2267. FIG. 19 is somewhat similar to FIG. 18, except that
the three bars 2265 with attached fins are arranged horizontally
and each has one end rotatably secured to a lower horizontal bar
attached to two vertical posts 226 and the other end rotatably
secured to an upper horizontal bar to 266. Rotation of the bars
2265 is controlled by spring 2267 which is secured to the upper
horizontal bar and the swimmer body.
[0186] In FIGS. 20 and 21, there is a single post having a bar 2265
rotatably secured to its top. The leading edge of the fin is
secured to one end of the bar 2265. The lower legs 311 and 312 of
tether 31 are secured to the ends of the bar 2265, and leg 312
includes spring 2267. Rotation of the bar 2265 is limited by
flexible line 2268. Fixed horizontal stabilizer fin 225 is secured
to the trailing end of the swimmer body.
[0187] FIGS. 22A-22C show the different configurations of a swimmer
comprising a swimmer body 21 having a rigid rear section 214 having
horizontal fixed stabilizer 225 secured thereto; a central section
228 which can be deformed elastically in the vertical plane but not
substantially deformed in the horizontal plane; and a rigid front
section 212 to which a rigid fin 213 is secured. A tether 31 is
secured to front section 212. In FIG. 22A, the swimmer is in still
water. In FIG. 22B, the swimmer is being pulled upwards. In FIG.
22C, the tether tension has dropped, and the weight of the swimmer
is forward of the center of lift, causing the front section to tilt
downwards.
[0188] FIG. 23 shows a swimmer which operates in a way similar to
the swimmer shown in FIG. 22. The rigid fin 213 rotates relative to
rigid swimmer body 211, and the tether is attached to the top of a
post 226 which rotates relative to the fin and the swimmer body,
and which carries a stabilizing weight 226 at its bottom end.
[0189] FIGS. 24 and 25 show swimmers in which the fin system
comprises two fins 233 which rotates about an aligned axis and are
connected, at points outboard of the swimmer body, to transverse
bottom legs 315 and 316 of tether 31. The swimmer shown in FIG. 24
also comprises rigid fixed vertical fins 223 at the leading end of
the swimmer body.
* * * * *