Note: Descriptions are shown in the official language in which they were submitted.
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CYCLOIDAL MARINE-PROPULSION SYSTEM
I. TECHNICAL FIELD
[0001] The present technology relates generally to a cycloidal-marine
propulsion
system. In some embodiments, the technology relates more particularly to a
cycloidal
marine-propulsion system comprising multiple electric motors for controlling
individually each of multiple respective cycloidal blades.
II. BACKGROUND
[0002] A cycloidal-drive propeller system is a specialized marine
propulsion system
allowing high maneuverability. The system allows change of vessel thrust to a
direction
and magnitude per command.
[0003] Cycloidal-drive propeller systems are used widely in vessels for
which station
keeping and high maneuverability at lower speeds are central functions, such
as tugboats,
ferries, and offshore support vehicles. A conventional type of cycloidal-drive
propeller
system is a Voith-Schneider propeller (VSP) system.
[0004] Conventional cycloidal propeller systems use heavy-duty drive
engines such
as a diesel motor drive. The drive provides input power and torque for a
relatively
complex group of intermediary structures leading to a complex mechanical
gearbox and
crosshead arrangement.
[0005] The drive engine of conventional systems is also connected to the
mechanical
gearbox and slider arrangement by way of a series of relatively intermediate
structures
and a main, vertical, system shaft. The intermediate structures include, for
instance,
couplings (e.g., displaceable coupling), intermediate drive shafts such as a
Cardan shaft,
and step-down gears, with or without one or more clutches.
[0006] During vessel movement, and especially high-vessel-speed operation,
the
vertical propeller blades of a cycloidal drive create undesirably high drag in
the water.
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The drag is particularly high under certain conditions, such as during
continuous running
of the vessel at high power. The drag slows the vehicle, limiting speed and
thus vessel
efficiency. The drag also lowers fuel economy, requiring more power and so
fuel to
overcome the drag.
[0007] Due to the relatively complex intermediate structures, mechanical
gearbox,
and crosshead arrangement described, response time between a triggering input
¨ e.g., a
signal transmitted in response to a captain pulling a lever ¨ and the desired
response is
also undesirably high. The complex mechanical drive is also noisy and causes
unwanted
vibration due to unbalanced forces and couples.
SUMMARY OF THE EMBODIMENTS
[0008] Given the aforementioned deficiencies, there is a need for a
cycloidal marine-
propulsion system that reduces significantly drag formed at vertical propeller
blades of
the system during high-vessel-speed operation.
[0009] The present technology accomplishes this and other goals in various
embodiments. In one embodiment, the system includes multiple electric drives
connected
to respective cycloidal-propeller blades for controlling the respective blades
selectively.
Each electric drive allows complex and fine control of position and movement
of the
blade to which it is connected.
[0010] Each blade can be moved, independent of movement of each of the
other
blades, and independently of a rotational position of the vertical main
assembly. Both
independences are distinctions compared to the conventional mechanical drive
system.
[0011] Each blade can be moved in any of a variety of ways to reduce drag
and
accomplish other desired functions such as creating, increasing, and/or re-
directing thrust.
[0012] One way each blade can be repositioned or moved selectively is by
rotating
the blade about a primary, longitudinal (extending along a primary length,
usually
generally vertical of the blade ¨ reference axis 117 in FIG. 1).
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[0013] In a contemplated embodiment, each blade can also be tilted, or
pitched,
whereby an angle of a blade axis (e.g., axis 117) is changed. This embodiment
is
described more below.
[0014] In still another contemplate embodiment, all of the blade axis can
be moved
toward or away from a main system axis (e.g., axis 107, FIG. 1). And each
blade can be
moved in more than one manner at a time ¨ e.g., tilted, while being rotated
about its blade
axis, and both at the same time that the blade is being moved with the other
blades about
the main system axis. These aspects are also described more below.
[0015] In addition to providing increased ability to reduce drag and in
some
instances increase thrust, the individual blade control of the present
technology improves
response time between desired blade action (e.g., positioning or motion)
resulting from
input signals ¨ e.g., an input signal from the controller or a vessel captain
to increase
speed and/or operate in a low-drag, or energy-efficient, mode, and can also
reduce noise
(e.g., underwater, or underwater and noise passing to the air) and vibrations
(e.g.,
underwater and into the vessel).
[0016] In some embodiments, efficiency, as well as fine control, are
further
promoted by a direct electric drive. The electric drive is linked directly to
a main system
axis shaft and, thereby, to a disc or plate holding the propeller blades. The
direct electric
drive also promotes quick response ,ime between input and resulting propeller
action.
[0017] Further features and advantages, as well as the structure and
operation of
various embodiments, are described in more detail below with reference to the
accompanying drawings. The technology is not limited to the specific
embodiments
described herein. The embodiments are presented herein for illustrative
purposes only.
Additional embodiments will be apparent to persons skilled in the relevant
art(s) based on
the teachings contained herein.
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IV. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Exemplary embodiments may take form in various components and
arrangements of components. iixemplary embodiments are illustrated in the
accompanying drawings, throughout which like reference numerals may indicate
corresponding or similar parts in the various figures.
[0019] The drawings are only for purposes of illustrating preferred
embodiments and
are not to be construed as limiting the technology. Given the following
enabling
description of the drawings, novel aspects of the present technology will be
evident to a
person of ordinary skill in the art.
[0020] FIG.1 is a perspective view of the cycloidal marine propulsion
system
positioned in a marine vessel.
[0021] FIG. 2 is a side cut-away view of the system of FIG. 1.
[0022] FIG. 3 is a schematic diagram of a computing device for use in
performing
functions of the present technology.
[0023] FIG. 4 is a flow chart showing operations of a method performed by
the
present technology.
V. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] While exemplary embodiments are described herein with illustrative
embodiments for particular implementations, it should be understood that the
technology
is not limited thereto. Those skilled in the art with access to the teachings
provided herein
will recognize additional modifications, applications, and embodiments within
the scope
thereof, and additional fields in which the cycloidal marine-propulsion system
described
herein would be of significant utility.
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Figure 1 ¨ System Components
[0025] FIG.1 is a perspective view of a cycloidal marine propulsion system
100,
positioned in a marine vessel 101, according to embodiments of the present
technology.
The system 100 includes a primary drive 102.
[0026] In one embodiment, the primary drive 102 is a fully electric drive.
[0027] The drive 102 is in one embodiment linked directly (e.g., without
complex
intermediary components such as clutches, step down or up gears) to a main
vertical
system shaft 104 of the system 100. The drive 102 is in this case referred to
as a direct
drive ¨ e.g., a direct electric drive.
[0028] The main shaft 104 is connected rigidly to a blade-mounting disc
106, and the
two rotate about a main system axis 107 in operation.
[0029] The system 100 also includes at least one angle sensor (not shown in
detail)
positioned on or adjacent the main shaft 104.
[0030] A direct-drive arrangement promotes efficiency and fine control of
the
system 100, as losses from intermediate structure (e.g., couplings, such as a
displaceable
coupling, intermediate drive shafts such as a Cardan shaft, and step-down
gears, with or
without one or more clutches) that would otherwise be present are avoided or
greatly
limited.
[0031] A direct drive arrangement, e.g., a direct electric drive, also
allows very fast
system response. By limiting intermediate structure between the drive 102 and
the
propeller disc 106, time between an input signal, initiated by a system
controller or vessel
operator, and resulting propeller action ¨ e.g., rotation of propeller disc
106. A system
controller is described further below.
[0032] An electric motor 102 is in one embodiment a synchronous motor. The
motor
102 may be a wound-field or permanent-magnet type of motor. In one embodiment,
the
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motor 102 is an induction-type motor. And in another, the motor 102 is a
reluctance-type
motor.
[0033] In contemplated embodiments, the main drive 102 is not electric, or
not
entirely electric, being, e.g., a type of diesel engine or other internal
combustion engine
(e.g., Otto, petrol, gas turbine, etc.) The drive 102 can include hydraulic or
pneumatic
features, and connect directly or indirectly to the main shaft 104. The drive
102 is
described further below, including in connection with FIG. 2.
[0034] In one contemplated embodiment, the main assembly drive 102 includes
or is
connected to a geared system (not shown) for turning the main shaft 104. The
geared
system can include a gear ring, located on a periphery of the main shaft 104,
connected to
one or more pinion gears driven by one or more high speed motors.
[0035] The blade-mounting disc 106 can be referred to by other names, such
as main
rotating assembly, or lower, inner, structure. The disc 106 rotates with
respect to a lower,
outer, structure or frame described further below in connection with FIG. 2,
and reference
numeral 210.
[0036] The drive 102 ¨ e.g., direct drive ¨ is in some embodiments
controlled by a
controller using a control map. The map comprises at least one algorithm
according to
which the main shaft can be controlled. The map can use as inputs, to
determine main
shaft operation, any of a wide variety of input data, such as any of output
from the on-
blade or adjacent-blade angle sensors, output from main assembly angle
sensor(s), system
power being used, system power available, present vessel speed, vessel
attitude (e.g., roll
or pitch), vessel speed desired or requested (by command of a vessel operator
or the
controller 300 (FIG. 3), for instance), wind speed, ambient water temperature,
water
depth present heading and/or position, heading and/or position desired or
requested (by,
e.g., command of a vessel operator or the controller), a type or
characteristic of the vessel
101, a propulsion layout, vessel-captain command, controller auto-generated
command,
etc.
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[0037] The type of vessel will influence the method and type of control,
since it is
important for certain vessels to have accurate station-keeping
characteristics, for
example, platform supply vessels, or to have fast transit times, but still
require improved
maneuverability, such as in the case of ferry boats.
[0038] The propulsion layout, relative to the vessel center of gravity, or
other vessel
handling parameter, will require the control map to take into account those
characteristics
and parameters. For example, a tug customarily has two propulsion units at the
furthest
aft section of the hull, whereas a ferry could have the propulsion unit at the
forward and
after parts of the ship.
[0039] The shaft 104 is controlled to accomplish desired vessel dynamics,
such as
vessel speed, vessel-speed vector, vessel thrust, and vessel attitude.
[0040] The control map can also be configured to control the system 100 in
a manner
that lowers or minimizes drag created by one or more of the blades, thereby
improving
fuel efficiency. The control can also be performed to maintain or produce more
thrust,
and can effected in less time than conventional systems, as mentioned above.
[0041] The control can include controlling movement of the main shaft 104.
These
control features are described further below in connection with FIGs. 3 and 4.
[0042] The system 100 further includes multiple actuators 108, such as
electric
motors, mounted locally to the propeller disc 106. Each actuator 108 is
connected to
respective system propeller blades 110.
[0043] Each blade 110 includes a distal end 112 that is positioned below a
bottom
113 of the vessel 101 and, during operation of the system 100, positioned in
the water
115 in which the vessel 101 is positioned.
[0044] Each actuator 108 is controlled by control signals received from a
system
controller, for instance, as described further below. While actuators 108 can
be controlled
to move their respective blades 110 according to some relationships (e.g.,
each blade is
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controlled to be positioned 20 degrees further in its rotation, about its
blade axis, than a
preceding adjacent blade on the disc 106), each actuator 108 is controlled to
drive its
respective blade 110 to move, or not move, independent of any motion of any of
the other
blades. That is, each actuator/blade pair can be controlled to move while each
other
actuator/blade is moved in any way, or kept from moving.
[0045] Thus, while one of the blades 110 can be rotated by a first angle in
a first
direction (e.g., clockwise) about its longitudinal (e.g., usually vertical)
axis, for instance,
another of the blades 110 can be controlled to move in any way, according to
the control
map, which can contain one or more algorithms for these purposes, such as by
rotating in
the same or an opposite direction by the same or another angle, or controlled
to not move.
[0046] The system 100 also includes angle sensors on or adjacent each blade
110.
These sensors are in one embodiment a part of the actuators 108. For
simplicity, the
sensors considered illustrated by the components 108 in the figures, though
the sensors
may be physically distinct from and/or connected to the actuators 108.
[0047] In the illustrated embodiment, the system 100 includes five
actuators 108
(labeled respectively in the figures as 108A -E) connected to five respective
propeller
blades 110 ¨ 110A-E. While five blades linked to five actuators are shown by
way of
example, it should be appreciated that the system 100 can include any number
of
actuators and respective blades.
[0048] The actuators 108 in some embodiments are controlled by, or include,
or are,
one or more electric motors. These electric motors are considered shown by the
same
structure 108 in the figures. The actuators 108 in some embodiments include or
are
controlled by one or more other types of drives, such as pneumatic or
hydraulic drives,
considered shown by the same structure 108 in the figures.
[0049] The actuators 108 in some embodiments include electric stepper
motors. In
one embodiment, the actuators are reluctance-type motors. Considerations in
selecting or
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designing a motor of the actuators 108 include any or all of responsiveness
(e.g., response
time), strength, robustness, durability, and noise reduction.
[0050] The actuators 108 can be operated to control velocity ¨ speed and
direction of
movement, angular and/or linear ¨ of the respective blades 110.
[0051] In operation, position of each blade 110 changes in a rotation phase
of the
system 100 in which the rotating disc 106 is being rotated. The blades 110
being rotated
by the disc 106 can create vectored thrust.
[0052] Disc rotation and/or individual blade rotations can be, as mentioned
above,
controlled separately by a controller implementing a control map, or algorithm
therein.
The control map can use as inputs, to determine main shaft operation, any of
various
inputs, such as any of output from the on-blade or adjacent-blade angle
sensors, output
from main assembly angle sensor(s), system power being used, system power
available,
present vessel speed, vessel speed desired or requested (by, e.g., command of
a vessel
operator or the controller 300 (FIG. 3)), wind speed, ambient water
temperature, water
depth present heading and/or position, heading and/or position desired or
requested (by,
e.g., command of a vessel operator or the controller), a type or
characteristic of the vessel
101, a propulsion layout, vessel-captain command, controller auto-generated
command,
etc.
[0053] Angular speed of any of the blades 110, about a respective blade
axis 117 can
be increased during the rotation phase to increase thrust. Angular speed of
any blade,
about its axis 117, can also be changed to decrease drag of the blade 110 in
the water 115
when the vessel 101 is moving.
[0054] The blades 110 are controlled individually to accomplish desired
vessel
dynamics ¨ e.g., vessel speed vector, thrust, and attitude. The map, or
algorithm, can also
be configured to control the vessel to lower or minimize drag created by one
or more of
the blades 110 against the water 115, to improve fuel efficiency, and the
like.
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[0055] In a contemplated embodiment, thrust created by each blade 110,
and/or an
amount of drag caused by each blade 110 moving through the water 115, can also
be
affected by posture or position of the blade 110 with respect to the disc 106
¨ e.g., tilt
angle of the blade axis 117. Any one or more of the blades 110 can be moved
selectively
so that a lower, distal, tip 114 of the blade 110 moved radially outward,
farther from the
main system axis of rotation 107.
[0056] Each blade can be moved in more than one manner at a time, as
mentioned. A
blade can be tilted (i.e., changing an angle of the blade axis 117 with
respect to the main
system axis 107), e.g., while it is being rotated about its blade axis 117.
And the blade
can be tilted while being rotated about its blade axis, and both at the same
time that the
blade is being moved with the other blades about the main system axis. The
blade can
also be translated, as a whole, toward or away from the main system axis 107
while the
blade is being moved in another way, such as being rotated about its axis 117
and/or by
tilting ¨ changing an angle of the blade axis 107 with respect to the system
main axis 117.
[0057] In one embodiment, the system 100 or at least the vessel 101
includes a thrust
plate 116. The plate 116 is in the illustrated embodiment suspended below the
vessel 101
and positioned just below the tips 114 of the blades 110.
[0058] In a particular contemplated embodiment, posture of each blade 110
can also
be controlled by the controller, implementing the control map, or algorithm,
based on any
of the controller inputs described herein. The controller and control map or
algorithm are
described further below regarding FIGs. 3 and 4.
[0059] The individual cycloidal-system blade control of the present
technology,
using an electric drive controlling each of multiple cycloidal propeller
blades, e.g., allows
complex and fine control of blade angles. The blades can be controlled to
accomplish
benefits including desired vessel dynamics, such as mooring, translating, or
linear
movement ¨ e.g., straight forward, reverse, or sideways motion.
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[0060] The blade control can, as referenced above, be performed, according
to the
control map, in ways to reduce drag. Drag can be reduced, e.g., by controlling
individual
blades separately so that each blade 110 creates a limited amount of friction
with the
water 115 through which the blades 110 are moving.
[0061] The map can be configured to cause each blade 100 to, at every
instance, be
positioned and/or moved to create a desired thrust while minimizing drag
created by the
blade. The map can be configured to cause each blade 100 to, at every
instance, be
positioned and/or moved to minimize drag while not performing a thrust-
creating action
at the moment.
[0062] An individual-blade-control arrangement also improves system
response by
limiting intermediate structure between the drive 102 and the lower disc 106,
such as the
complex mechanical gearing and sliders of the conventional VSP arrangements.
In this
way, time is limited between an input signal, initiated by a system controller
or vessel
operator, and resulting blade positioning or motion.
Figure 2 ¨ Cycloidal Propulsion System in More Detail
[0063] FIG. 2 is a cut-away of the system 100 of FIG. 1. The embodiment
shown
includes upper bearings 202 and lower bearings 204.
[0064] The upper bearings 202 facilitate turning of the main shaft 104, or
structure
connected rigidly to the axis 104, with respect to adjacent static structure.
The upper
bearings 202 are positioned between an upper inner edge 206 connected rigidly
to the
main shaft 104 and an upper outer edge 208 connected to framing of the vessel
101.
[0065] The lower bearings 204 facilitate turning of the main axis 104, or
moving
structure connected rigidly to the main shaft 104, with respect to adjacent
static structure.
The lower bearings 204 are positioned between, for instance, a lower inner
edge 210
connected rigidly to the main shaft 104 or disc 106, and a lower outer edge
212 connected
to adjacent framing of the vessel 101.
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Figure 3 ¨ Computer System
[0066] FIG. 3 is a schematic diagram of a computing device 300 for use in
performing functions of the present technology. The device 300 is configured
to control
various functions of the system 100, and can also be referred to as a
controller.
[0067] Although connections are not shown between all of the components
illustrated in FIG. 3, the components can interact with each other to carry
out computer
system functions.
[0068] The computer device 300 includes a memory, or computer-readable
medium
302, such as volatile medium, non-volatile medium, removable medium, and non-
removable medium. The term computer-readable media and variants thereof, as
used in
the specification and claims, refer to tangible or non-transitory, computer-
readable
storage devices.
[0069] In some embodiments, storage media includes volatile and/or non-
volatile,
removable, and/or non-removable media, such as, for example, random access
memory
(RAM), read-only memory (ROM), electrically erasable programmable read-only
memory (EEPROM), solid state memory or other memory technology, CD ROM, DVD,
BLU-RAY, or other optical disk storage, magnetic tape, magnetic disk storage
or other
magnetic storage devices.
[0070] The computer device 300 also includes a computer processor 304
connected
or connectable to the computer-readable medium 302 by way of a communication
link
306, such as a computer bus.
[0071] The processor could be multiple processors, which could include
distributed
processors or parallel processors in a single machine or multiple machines.
The processor
can be used in supporting a virtual processing environment. The processor
could include
a state machine, application specific integrated circuit (ASIC), programmable
gate array
(PGA) including a Field PGA, or state machine. References herein to processor
executing
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code or instructions to perform operations, acts, tasks, functions, steps, or
the like, could
include the processor performing the operations directly and/or facilitating,
directing, or
cooperating with another device or component to perform the operations.
[0072] The computer-readable medium 302 includes computer-executable
instructions, or code 308. The computer-executable instructions 308 are
executable by the
processor 304 to cause the processor, and thus the computer device 300, to
perform any
combination of the functions described in the present disclosure.
[0073] The instructions 308 include instructions or code 309 for
controlling
operation of the system 100 (FIGs. 1 and 2). The code 309 routes, or maps,
various
conditions, indicated by conditions of the vessel 101 to output commands for
one or more
controllable components of the system 100. The code 309 may be referred to as
a control
map, mapping code, routing code, decision, and includes various algorithms
defining any
desired relationships between conditions and respective commands.
[0074] Example input to the control map 309 includes those referenced
above, such
as any one or combination of: output from the on-blade or adjacent-blade angle
sensors;
output from main assembly angle sensor(s); system power being used; system
power
available; present vessel speed; vessel speed desired or requested (by, e.g.,
command of a
vessel operator or the controller 300); wind speed; ambient water temperature;
water
depth; heading or position desired or requested (by, e.g., command of a vessel
operator or
the controller 300); a type or characteristic of the vessel 101; a propulsion
layout; vessel-
captain command; controller auto-generated command, etc.
[0075] The control map 309 in one embodiment includes mapping, to one or
more
appropriate outputs, any of various combinations of such inputs and
indications
communicated by the inputs. Example indications include whether a device or
condition
is present/not present, on/off, percentages (e.g., percentage of vessel power
being used or
available), levels (e.g., vessel speed, water temperature), amounts (e.g.,
remaining batter
power), and/or other values (e.g., angular, linear, or other position relating
to the main
axis 104 or any propeller blade(s) 110).
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[0076] Outputs include commands or signals instructing operation of one or
more
components of the system 100. The controllable components can include the main
system
drive 102 controlling rotation of the main axis 104. As mentioned, the main
drive 102 in
one embodiment includes an electric drive linked directly to the main axis
104. Aspects
of the main axis 104 controlled include primarily direction of rotation and
speed of
rotation. The main axis rotation affects directly rotation of the blade-
mounting disc 106,
and so rotation of all of the blades 110, about the main system axis 107.
[0077] The controllable components can also include each of the propeller
blades
110. In these embodiments, the blades 110 are configured and connected to the
mounting
structure or disc 106 to be moved independently of any motion or non-movement
of any
of the other blades. For instance, the configuration and arrangement allows
the controller
300 to affect counter-clockwise rotation, about its axis 117, of a first of
the blades 110, at
a first speed, while adjacent blades 110 are kept from rotating about their
axes 117,
rotated clockwise, or rotated counter-clockwise at a different speed, etc.
[0078] The blades 110 are in some embodiments also configured and connected
to
the mounting structure or disc 106 to be moved independently of any motion,
non-
movement, or rotational position of the vertical main assembly
[0079] The mapping code 309 can be arranged in any manner connecting
various
inputs (e.g., vessel-captain commands and water conditions) with pre-set
corresponding
outputs (operational signals to system components). The mapping code 309 is in
one
embodiment arranged in an array format, such as a matrix, connecting various
conditions
(e.g., inputs) to corresponding outputs (e.g., component-specific control
commands).
[0080] As a simple example of an output (e.g., control command)
corresponding in
the map 309 to a base condition (e.g., inputs), the input can include the
controller 300 or
the vessel operator issuing, while the vessel is not creating, or not to be
creating, thrust
(e.g., gliding to a dock), a command requesting or relating to a desire to
limit drag. The
command can include or be related to a request for power or energy savings.
Output in
this example could include a command to the main drive 102 to stop (if not
already
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stopped) and a command to one or any combination including all blades 100 to
align to a
present or desired vessel direction (i.e., so that main lateral portions of
the blade(s) are
facing perpendicular to the present or desired direction) so that the blades
create limited
drag as they are moving through the water 115 with the vessel 101. This may be
an
appropriate request, and resulting command, for situations in which a vessel
(e.g., ferry)
is approaching a stop at a slow speed sufficient for the vessel to reach a
destination (e.g.,
dock being approached) if drag is minimized. In this scenario, power and
energy (e.g.,
fuel) are saved.
[0081] As another power/energy-saving example, a vessel operator, or the
controller
300, can issue a command for power or energy saving vessel movement. The
movement
can include starting vessel movement in any desired direction ¨ linear and/or
turning. In
the linear-movement example, the cycloid system 100 can be used to create
linear vessel
movement in any direction.
[0082] Because drag limits vessel movement, vessel speed can be maintained
or
reached with less thrust if drag is lowered. Thus, for energy saving mode, the
vessel
speed can be increased simply by reducing drag, without increasing rotation
speed of the
main axis (and so discs 106 and blades 110 in their collective rotation about
the axis 107).
Reducing drag can be accomplished by controlling each blade 110,
independently, to at
all times have a position that limits drag under the circumstances, such as to
limit drag
while also being moved to create the existing thrust level.
[0083] While a control variable can include a rotational position of the
blade 110
about the main axis 107, the system is in some embodiments, as mentioned also
configured so that each blade can be moved independently of any motion, non-
movement, or rotational position of the vertical main assembly.
[0084] One or more of the blades may at times be moved in the same manner,
but
generally each blade would be controlled to move and be positioned differently
in this
scenario. Such independent control is impossible using conventional cycloidal
systems in
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which operation of each cycloid blade is linked to movement of the other
blades by
complex mechanical gearing.
[0085] Blade adjustment can include controlling direction and rate of blade
rotation
about its axis 117.
[0086] Blade adjustment can instead or also include controlling a pitch or
tilt of the
blade 110 ¨ e.g., tilting the blade and its axis 117, such as by moving a
lower tip of the
blade outward, away from the main system axis 107.
[0087] Thrust created by a blade 110 can be increased by adjusting or
controlling
any one or more of blade movement or position about its axis 117, its movement
or
position about the main axis 107, and a tilt angle of the blade (e.g., tilting
the blade so a
lower tip is moved away from or toward the main system axis 107).
[0088] At the same time or separately, drag created by a blade 110, moving
through
the water 115, can be reduced by adjusting or controlling any one or more of
blade
movement or position about its axis 117, its movement or position about the
main axis
107, and a tilt angle of the blade (e.g., tilting the blade so a lower tip is
moved away from
or toward the main system axis 107).
[0089] In a contemplated embodiment, system 100 is configured so that the
blade
110 may be moved in its entirety away from the main axis to accomplish desired
results
(e.g., increasing thrust and/or reducing drag). The disc 106 or structure
connected thereto
would in this case be arranged to that each blade, or every blade together,
can be moved
away from the main axis 107. The lower tip of the blade 110 can be moved away
from or
toward the main axis 107 by an equal amount that an upper tip of the blade 110
is moved
away from or toward the axis 107, so that the blade axis 117 angle is kept
constant in the
motion. Or the blade axis 117 can angle can change in the motion, such as by
the lower
tip 114 being moved out more slowly than an upper tip of the blade 110.
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[0090] Drag created by each blade 110 is reduced when, e.g., each blade 110
is
controlled to an optimum rotational position (i.e., about its axis 107)
vertical position
according to an absolute rotational position of the main assembly relative to
the intended
thrust direction. The reduction of drag can be achieved by modifying the local
blade
rotational position as the main assembly absolute position alters.
[0091] As a related energy-saving example, linear vessel speed can be
maintained
while less power/energy is used. Due to the drag characteristics mentioned
above, linear
speed of the vessel 100 can be maintained while one or more aspect of the
system 100
can be slowed, e.g., rotation of the main axis 104, simply by adjusting the
blades in real
time to reduce drag.
[0092] The control map is configured to optimize the drag reduction
according to
factors such as vessel direction, speed, and desired speed based on inputs
such as those
from ship sensors including those sensing parameters including attitude in
roll, pitch, and
yaw. In some implementations, a greatest drag reduction effect is generated as
part of
providing, by blade control, steering and speed required. It will be
appreciated that the
blades providing thrust are not limited to providing thrust and steering
functions ¨ e.g.,
the blades moving in a forward direction, meaning returning towards the thrust
provision
position, can be used to provide direction thrust. This division of duties
means that the
blades may be more or less active during main assembly vertical axis
positional change.
In some instances, such as when the vessel is in deep water, or at full-away,
the position
of the vessel will need correcting without reduction in thrust.
[0093] The term lull-away' refers to conditions, when operating a ship,
wherein the
ship is clear of navigation obstacles, and the propulsion system of the ship
can be
operated to any desired power level desired ¨ e.g., a level to match a mission
profile. On
ferries, full-away can involve the conditions allowing the ferry to operate at
full power.
Full-away can also refer to such operation of the ship (e.g., without limits,
at full power,
etc.). On liners, full-away could include the liner operating according to a
schedule at a
power level of between about 30 and about 100% of full load depending on
factors such
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as distance between ports, weather, and so on. Full-away can also refer to
operation of the
propulsion system under conditions will not change notably in substantive ways
during
the voyage (e.g., during a full-away portion of the voyage) until nearing
shore or
navigation obstacles.
[0094] The computer system 300 further comprises an input/output (I/O)
device 310,
or communication interface, such as a wireless transceiver and/or a wired
communication
port. The processor 304, executing the instructions 308, receives input from
any of a wide
variety of input sources 312 and provides output to any of a wide variety of
outputs 314.
[0095] Example input devices 312 include a temperature sensor (air, water,
engine,
motor, etc.), main-axis-shaft rotation-speed sensor, blade-position sensor,
blade-rotation-
speed sensor, other blade-position or movement sensor, vessel-speed sensor,
the
controller itself (providing, e.g., a command or other input by the processor
from one
portion of instructions (e.g., map 309 or other code 308) to another (e.g.,
the map 309),
system power sensor or indicator, (by, e.g., a command of a vessel operator or
the
controller 300 (FIG. 3)), wind-speed sensor, water-depth sensor, vessel-
heading or
position (e.g., GPS) sensor or indicator, data indicating a characteristic
(e.g., an intrinsic
feature) or type of the vessel 101, a sensor or indicator expressing data
about vessel
propulsion layout, data from a vessel-captain, etc.
[0096] Communications to/from the device 310 can be in the form of signals,
messages, or packetized data, for example. The device 310 can include one or
more
transceivers, transmitters, and/or receivers. The device 310 can include wired
and/or
wireless interfaces for communicating with the input and output components
312, 314.
Figure 4 ¨ Methods of Operation
[0097] FIG. 4 is a flow chart showing operations of a method 400 performed
by the
present technology, according to an embodiment of the present disclosure.
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[0098] Operations, or steps, of the method 400 are not necessarily
presented in any
particular order and that performance of some or all the steps in an
alternative order is
possible and is contemplated. The steps have been presented in the
demonstrated order
for ease of description and illustration. Steps can be added, omitted and/or
performed
simultaneously without departing from the scope of the appended claims.
[0099] The illustrated method 400 can be ended at any time. In certain
embodiments,
some or all steps of this process, and/or substantially equivalent steps are
performed by
execution of computer-readable instructions, such as the instructions 308
including the
control map 309, stored or included on a computer readable medium, such as the
memory
302 of the controller 300.
[00100] The method 400 begins 401 and flow proceeds to block 402, whereat
the
controller obtains a vessel-kinematic, or motion or movement, command. Though
the
command is termed a kinematic, or movement or motion, command, and while the
command can include initiating a vessel motion different than a current
motion, the
vessel-kinematic command can also be configured to (i) maintain an existing
vessel
motion, such as a current speed or direction, to (ii) stop the vehicle in any
one or more
directions (angular or linear), or to (iii) maintain a non-motion state.
[00101] The obtaining operation can include receiving the command, being
pushed to
the processor 304. In one implementation, the obtaining includes the processor
304
retrieving the command ¨ e.g., requesting and receiving the command.
[00102] The command in some cases is generated by the controller 300 ¨
i.e., by the
processor 304 executing instructions 308. The command can be generated, e.g.,
in
response to a determination by the controller 300 that a vessel speed and/or
direction
change is needed, such as to maintain a pre-set vessel course or to avoid an
obstacle.
[00103] The command can also be initiated by an order of a vessel operator,
such as
from a vessel captain selecting a hard or soft button indicating a power-
saving or energy-
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saving mode, moving a soft or hard control for changing vessel direction,
and/or moving
a soft or hard vessel control for changing vessel speed.
[00104] At step 404, the controller accesses and processes the control map
309. At
step 406, the processor 304, executing the control map 309, obtains (e.g.,
receives or
retrieves) input data to be used in processing the control map 309. Some or
all of the
inputs may already be present before or when the processor 304 accesses the
control map
309, and some or all of the inputs may be retrieved by the processor 304 in
response to
determining the input(s) is/are needed in processing the control map.
[00105] The inputs may be received from any of a wide variety of sources
without
departing from the scope of the present technology. The inputs can be received
from the
processor 304 executing certain aspects of the instructions, even of the
control map 309.
The inputs can be received from other electronic components of the vessel 100,
such as
any of the sensors described herein (vessel-speed, vessel-attitude, vessel-
location, blade-
rotation-speed, water-temperature, water-depth, etc.), or the like.
[00106] The processor 304, executing the control map 309, determines (e.g.,
generates), based on the inputs received, one or more ways to adjust or
maintain
operation of at least one vessel component. Block 408 represents an example by
which
the processor 304, executing the map 309, determines a command for controlling
(e.g.,
changing or maintaining) a rotational velocity of the main axis 104.
[00107] Block 410 represents another example, by which the controller,
executing the
map 309, determines (e.g., generates) one or more commands for controlling
(e.g.,
changing or maintaining) a position and/or rotational velocity (about blade
axis 117) of a
blade 110. The step 410 is in some implementations performed separately for
each blade
110. The separate performance can be made substantially simultaneously.
[00108] In some implementations, while each blade 110 is controlled
independently,
as mentioned, the controller determines the one or more commands for
controlling
position or rotational velocity of more than one blade at generally the same
time.
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[00109] At block 412, the main-axis command determined (indicating, e.g.,
an
instruction to increase main-axis speed by 2 revs/min.) is provided to the
main-axis driver
102 for maintaining or changing a rotational characteristic of the main shaft
104.
[00110] At block 414, the blade command determined (e.g., indicating an
instruction
to increase blade rotation about the blade axis 117) is provided to a blade
actuator 108
(e.g., independent electric motor) for maintaining or changing a positional
and/or
movement characteristic (e.g., increasing blade rotation) for the blade 110.
[00111] As with previous step 410, the present operation 414 is in some
implementations performed separately for each blade 110. The separate
performance can
be made substantially simultaneously. In some implementations, while each
blade 110 is
controlled independently, via its respective actuator (e.g., independent
electric motor), as
mentioned, the processor 304 can generate commands for controlling position or
rotational velocity of more than one blade at generally the same time, and
commands for
various blades can be related. As mentioned, for instance, actuators 108 can
be controlled
to move their respective blades 110 according to some relationships ¨ e.g.,
each blade is
controlled to be positioned 20 degrees further in its rotation, about its
blade axis 117, than
a preceding adjacent blade 110 of the blades 110 on the disc 106.
[00112] At operation 416, the controller determines whether a new vessel-
kinematic
command (VKC) is present. In some embodiments, the operation 416 includes a
passive
function of receiving, or not receiving, a new VKC. As provided, while the
command
(VKC) is termed a kinematic, or movement or motion, command, and while the
command can include initiating a vessel motion different than a current
motion, the
vessel-kinematic command can also be configured to (i) maintain an existing
vessel
motion, such as a current speed or direction, to (ii) stop the vehicle in any
one or more
directions (angular or linear), or to (iii) maintain a non-motion state.
[00113] If there is no new VKC, flow proceeds along return route 417 to
steps 404 et
seq., such as for any further processing and any new output determinations
that need to be
made or provided in order to maintain, reach, or get closer to reaching a
desired vessel
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state. Such subsequent iterations of the method 400 can include obtaining new
(e.g.,
different) and/or updated sensor data at block 406.
[00114] In response to a new VKC, such as from the controller or vessel
electronics
triggered by a vessel operator, at block 418, the new VKC is accepted, stored
in cache or
other memory as a current VKC, or otherwise processed by the processor 304 to
give
effect to the new VKC.
[00115] Following receiving the new VKC, flow proceeds along return route
419 to
steps 404 et seq., such as for any further processing and any new output
determinations
that need to be made or provided in order to maintain, reach, or get closer to
reaching a
desired vessel state. As shown by the figures, such subsequent iterations of
the method
400 can include obtaining new (e.g., different) and/or updated sensor data at
block 406.
[00116] The process 400 can be repeated, such as to effect one or more VKCs
over
time. The process 400 can be ended 421, such as by turning the controller 300
or the
system 100 off, or a vessel operator selecting an off or sleep-mode.
Benefits and Advantages
[00117] This section elaborates on benefits of the present technology
described above.
Benefits are achieved by the con rols described herein. The control features
include
controlling any or all of individual-blade position, individual-blade motion,
main-axis-
shaft position, and main-axis-shaft motion.
[00118] These controls can be achieved using, e.g., individually-
controllable blades,
electric-motor blade actuators, and a direct-drive (e.g., electric motor) for
main-shaft
control.
[00119] One of the primary advantages of the present technology is an
ability to lower
power and energy used by a marine cycloidal-propulsion system. As mentioned,
noise
(e.g., underwater noise and/or noise passed to the air) can also be reduced,
as well as
vibrations through the water, vessel, etc. The savings result in more-
efficient fuel
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consumption, lowered fuel cost (capital cost of operation), lower emissions,
and extended
ship range on the same amount of fuel.
[00120] Technical advantages of the present technology include an ability
to achieve
greater speeds, including greater speeds at an equivalent power expenditure,
by reducing
drag.
[00121] Another technical advantage includes improved vessel
maneuverability.
Improved vessel maneuverability is achievable by the ability to control each
blade 110
individually in real time.
[00122] Another benefit of the technology is a greater flexibility in
designing vessels.
The flexibility results from the greater maneuverability and speeds achievable
by vessels
incorporating the present technology. As a result, the vessel can be designed
in previously
unachievable ways without sacrificing maneuverability or speed.
[00123] The flexibility can also result from an ability to use any of a
variety of drives,
such one or more diesel and/or electric motors to control the main drive
shaft, and a
distinct controllable electric motor for each of the plurality of cycloidal
propeller blades.
Conclusion
[00124] Alternative embodiments, examples, and modifications that would
still be
encompassed by the technology may be made by those skilled in the art,
particularly in
light of the foregoing teachings. Further, it should be understood that the
terminology
used to describe the technology is intended to be in the nature of words of
description
rather than of limitation.
[00125] Those skilled in the art will also appreciate that various
adaptations and
modifications of the preferred and alternative embodiments described above can
be
configured without departing from the scope of the technology. Therefore, it
is to be
understood that, within the scope of the appended claims, the technology may
be
practiced other than as specifically described herein.
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