Aaron GOLDIN -- WaveGyro Generator

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**Aaron GOLDIN**  
**Gyro-****Gen Wave Power**

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[**http://www.blogger.com/**](http://www.blogger.com/)**Renewable Energy Law Blog** **January 14, 2005**[**http://www.eere.energy.gov/news/**](http://www.eere.energy.gov/news/)**DOE's Energy Efficiency and Renewable Energy (EERE) Network
News:**

**Student's Wave Energy Invention Wins
National Award**

Researchers and companies have been trying for decades to capture
the energy of waves to produce electric power, but the latest wave
energy invention comes from an unlikely source: Aaron Goldin, a
senior at San Dieguito High School Academy in Encinitas,
California. In December, Goldin won the $100,000 Grand Prize
scholarship from the 2004-2005 Siemens Westinghouse Competition in
Math, Science and Technology, the nation's premiere high school
science competition, for his invention of the "Gyro-Gen," a
gyroscope that converts ocean wave energy into electricity. The
spinning gyroscope, mounted in a buoy, resists the movement of the
waves by exerting torque on a crank, which turns an electric
generator. Goldin created his gyroscope prototypes in his garage,
scavenging an old tape recorder, answering machine, and other
household appliances for parts. The invention also won the
prestigious California Sea Grant John D. Isaacs Scholarship for
outstanding ocean engineering research in 2004.  
  

![](goldin-wavegyro.jpg)  
  
  


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[**http://renewablesoffshore.blogspot.com/2004/12/high-school-student-wins-top-prize-for.html**](http://renewablesoffshore.blogspot.com/2004/12/high-school-student-wins-top-prize-for.html)

**High School Student Wins Top Prize
for Ocean Device**

  
Aaron Goldin, whom we posted about here has won top prize in
the Siemens-Westinghouse high school science competition for a
wave energy device as reported in this story at MSNBC.
Unfortunately, the $100,000 prize will go to Mr. Goldin's
college. Too bad that it can't be used to actually develop
Goldin's device because with the current state of affairs in
wave energy development, the project may never be built. Of
course, $100,000 isn't much or nearly enough - but quite
frankly, it's more than what's available to any US wave energy
developer at this time.   
  


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[**http://www.signonsandiego.com/news/education/20041125-9999-1mi25invent.html**](http://www.signonsandiego.com/news/education/20041125-9999-1mi25invent.html)[**http://legacy.utsandiego.com/news/education/20041125-9999-1mi25invent.html**](http://legacy.utsandiego.com/news/education/20041125-9999-1mi25invent.html)**November 25, 2004**

**Award-winning invention turns
swells into electricity**  
  
**by**   
  
**Sherry Parmet**

  
ENCINITAS  Using old appliance parts in his garage,
17-year-old Aaron Goldin spent two years building an
environmentally friendly device that converts ocean wave
energy into electricity.  
  
The San Dieguito High School Academy senior constructed the
gyroscopic, wave-powered generator for the pure love of
science, rather than for a class project or grade.  
  
However, his research generated first-place awards in county,
state and international science fairs. And most recently, he
won the prestigious Western Regional Finals of the Siemens
Westinghouse Competition in Math, Science and Technology.
He'll compete next month in Washington, D.C., against five
others for a top prize of $100,000.  
  
Aaron said he's honored by the recognition, but more pleased
to have possibly discovered a practical, environmentally
friendly way to generate electrical power. He's seeking to
patent his invention.  
  
"I've always been interested in the environment, and growing
up right next to the beach I've observed and appreciated the
power of the wave," he said. "Gyroscopes I've played with
since I was a little kid. I'd balance them and hook them up to
motors."  
  
The Siemens Foundation in New Jersey is an extension of
engineering and telecommunications giant Siemens. It has
promoted its competition for six years to motivate student
involvement in math and science, and it awards more than $1
million in scholarships annually.  
  
The competition drew 1,250 high school entries from across the
nation, and one individual student winner from six regions
will compete next month. Aaron has already won a $3,000
scholarship and will come away with at least $10,000 more for
competing in the final round.  
  
To build his device, Aaron adapted a retired computer printer
part for the generator. The motor was from an old answering
machine. The gyroscope was from a flywheel from an older-style
reel-to-reel tape deck.  
  
His project was evaluated by a team of scientists and faculty
at the University of California Berkeley. Lead judge Roger
Falcone, a UC Berkeley physics professor, said Aaron's use of
a gyroscope was creative, original and impressive because of
its simplicity.  
  
"For many years, people have known that wave energy is very
powerful, but his solution using a gyroscope is novel," he
said. "We actually looked on the Web and at the patent office,
and we couldn't find any work done on this."  
  
Aaron said he believed the gyroscope might generate electrical
power from waves because it would automatically push back
against them, enabling it to absorb wave energy. Aaron said
his device is a free-floating system that is environmentally
benign.  
  
Aaron is a straight-A student who packs his schedule with
rigorous Advanced Placement classes, which cover material in a
more sophisticated way. He earned top marks on Advanced
Placement physics, calculus, chemistry and U.S. history tests,
earning him college credit for those courses.  
  
He has nonacademic interests as well. Aaron played the
trombone for local youth orchestras and currently plays for
Band in Black, a local jazz group. He plays piano and composes
music for fun.  
  
He is an avid reader, and his favorite book is "Crime and
Punishment" by Fyodor Dostoevsky. With his friends, Aaron
plays computer games such as "Warcraft III" and
"Counter-Strike."  
  
Someday Aaron would like to be a university research professor
in physics or engineering. His dad is an engineer, and Aaron's
parents are proud of their son's scientific work.  
  
"He doesn't care so much about the money, as much as the honor
of being able to participate in such a prestigious
competition," said his mother, Linda Goldin. "He really cares
about what his invention could possibly do for the environment
as an alternative energy source. It's nice his work has a
purpose to better society, and he feels strongly about it.
That makes me feel good."

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**Gyroscope-based electricity generator**  
**US7375436**

  
Inventor(s): GOLDIN AARON [US] +  
Classification: - international: F03B13/10; F02B63/04; F03B13/12;
F03G7/08; F16H33/00; H02K7/18; H02P9/04  
  
**Abstract** -- Techniques and devices that use precession of
at least one spinning gyroscope to drive a motor generator to
produce electricity from an oscillating motion that causes the
precession of the gyroscope. A buoy may be used to produce the
oscillating motion from the motion of water waves so that
electricity may be produced from motion of water waves. An
oscillating motion caused by other sources, such as wind, may also
be used to generate electricity.  
  
**BACKGROUND**  
This application relates to conversion of energy of a mechanical
motion into electrical energy.  
  
Energy is a valuable resource. A variety of techniques have been
and are being developed to generate energy from various sources,
such as the coal, oil, natural gas, hydrogen, sunlight, wind, and
ocean waves. Certain energy resources are limited on earth and are
not renewable. Examples of such energy sources include the fossil
fuels like coal, oil, and natural gas, and nuclear fuels such as
uranium. The fossil fuels, uranium and other non-renewable energy
sources will eventually be depleted on earth by continuous
exploration and use. The consumption and use of many non-renewable
energy sources such as fossil fuels and nuclear fuels are also
known for causing pollutions to the environments.  
  
In contrast, certain other energy resources, such as the sunlight,
wind, and ocean waves, are practically unlimited in their supply
and may be utilized in ways that can significantly reduce or
minimize adverse impacts to the environments and the earth's
ecological systems. Therefore, techniques, devices and systems for
obtaining energy from various sources other than fossil fuels and
nuclear fuels are desirable to preserve earth's natural resources,
to reduce pollution to the environments, and to expand energy
supply sources in order to provide sustainable energy supply to
humans.  
  
For example, the motion of water waves in a large body of water,
e.g., lakes, rivers, and oceans, may be used to generate
electricity. Oceans, in particular, have an enormous potential as
a source of energy in part because oceans cover over 70% of the
earth's surface and are estimated to have an annual capacity of
about 2000 tera watt-hour in the surface wave energy alone.  
  
**SUMMARY**  
This application describes implementations of techniques and
devices that use a spinning gyroscope to convert an oscillating
torque caused by an oscillating motion into a continuous torque
acting on an electromagnetic motor generator and thus cases a
continuous rotation of the electromagnetic motor generator which
generates electricity. In one implementation, for example, a
method is described to use a spinning gyroscope to convert an
oscillating motion into a continuous rotation motion and to cause
the continuous rotation motion to activate an electromagnetic
motor-generator to generate electricity.  
  
In another implementation, an exemplary device is described to
include a base reactive to an oscillating motion acting on the
base; a gyroscope engaged to the base and operable to precess in
response to the oscillating motion of the base when the gyroscope
is spinning; an electromagnetic motor-generator to rotate and to
generate electricity; and a coupling unit coupled between the
gyroscope and the electromagnetic motor-generator to transfer the
precession of the gyroscope to continuous rotation of the
electromagnetic motor-generator, thus converting energy of the
oscillating motion into electricity.  
  
In yet another implementation, a device is described to include a
floating device to float in water and a base engaged to the
floating device to be substantially parallel to a water surface at
a location where the base is located. This device includes a
gyroscope engaged to the base and operable to precess, when the
gyroscope is spinning, in response to an oscillating motion of the
base when floating on the water. An electromagnetic
motor-generator is engaged to the base and to rotate around a
motor rotation axis that is perpendicular to the base. This device
includes crank arm engaged to the electromagnetic motor-generator
and operable to rotate the electromagnetic motor-generator and
engaged to the gyroscope so that an axis of the spinning of the
gyroscope is parallel to the crank arm. The crank arm is operable
to transfer the precession of the gyroscope into continuous
rotation of the electromagnetic motor-generator, thus converting
energy of the oscillating motion into electricity. A control
module is coupled to control spinning of the gyroscope according
to a frequency of the oscillating motion.  
  
These and other implementations are described in greater detail in
the attached drawings, the detailed description and the claims.  
  
**BRIEF DESCRIPTION OF DRAWINGS****FIGS. 1 and 2 illustrate one implementation of a gyroscope
generator that converts energy of an oscillating motion into the
electricity.**![](fig1.jpg)**FIG. 3 illustrates operation of a spinning gyroscope under
a disturbing torque.**

![](fig3.jpg)

**FIG. 4 shows one example of a specific design of the gyroscope
generator in FIG. 1.**

![](fig4.jpg)

**FIG. 5 shows one example of a gyroscope generator for
converting energy of ocean waves into electricity based on the
design in FIG. 4.**

![](fig5.jpg)

**FIGS. 6A and 6B show exemplary circuits for the rotary motor
generator and the driver circuit for the gyro motor,
respectively, in a simplified testing prototype for the design
in FIG. 4.**

![](fig6.jpg)

**FIGS. 7, 8, 9 and 10 show measured data in a simplified testing
prototype for the design in FIG. 4.**![](fig7.jpg)

![](fig8.jpg)  
  

![](fig9.jpg)

**FIGS. 11A and 11B show block diagrams of two exemplary
gyroscope-based generators that implement a system controller
and a power regulator based on various sensors.**

![](fig11.jpg)  
  
![](fig11b.jpg)

**FIG. 12 shows an exemplary operation of the system controller
in the buoyant gyroscope generator.**

![](fig12.jpg)

**FIG. 13 shows one example of a gyroscope-based generator where
two gyroscopes are used and coupled to each other.**

![](fig13.jpg)

**DETAILED DESCRIPTION**  
  
The techniques and devices described in this application use a
spinning gyroscope to convert an oscillating torque caused by an
oscillating motion into a continuous torque acting on an
electromagnetic motor generator and thus cases a continuous
rotation of the electromagnetic motor generator. The
electromagnetic motor generator generates electricity from the
continuous rotation. A coupling mechanism is provided to transfer
or transform the precession motion of the spinning gyroscope under
the oscillating torque into the continuous rotation of the motor
generator. As described in detail below, the use of the spinning
gyroscope and the coupling mechanism can be implemented in simple
and efficient configurations that convert the energy of an
oscillating motion into electricity for a variety of applications.  
  
The implementation of the combination of the spinning gyroscope
and the coupling mechanism may be adapted different to efficiently
interact with different forms of oscillating motions. For example,
the oscillating motion may be caused by a natural phenomenon such
as water waves in, e.g., oceans and winds. Specific examples are
described here for designs that directly convert the periodic
torque of oscillating surface waves in a body of water such as
ocean waves into the continuous torque acting on a rotary electric
generator which in turn generates electricity. The spinning
gyroscope, which sometimes may be used as an inertial frame of
reference such as a horizontal spinning top, is configured to
continuously precess harmonically to the oscillating motion of the
ocean waves, usually with varying amplitudes and periods. This
precession of the spinning gyroscope is then used to drive the
rotary motor generator to continuously rotate and thus generate
electricity. The entirety or a portion of the generated
electricity may be directly used to power an electric load or
device. The entirety or a portion of the generated electricity may
also be used to charge up a rechargeable battery to store the
generated energy or be stored in other energy storage device. In
some applications, the generated electricity may be partially used
to drive an electric load or device while the remainder of the
generated electricity is being stored.  
  
In certain implementations, the spinning motion of the gyroscope
may be initiated or initially powered by a power supply such as a
battery. After the initial spinning of the gyroscope, the combined
operation of the spinning gyroscope and the coupling mechanism
generate electricity from a specific oscillating motion with which
the system is designed to interact. While a portion of or the most
of the generated electricity may be sent to the storage device or
may be used to drive the electric load, a portion of the generated
electricity from the rotary electric generator is partitioned out
of the generated electricity and is used to power the spinning
motion of the gyroscope. Therefore, after the initial powering by
the power supply, the gyroscope may be controlled to cease
receiving energy from the power supply after the partitioned
portion of the electricity generated by the motor is sufficient to
maintain spinning of the gyroscope. The power supply for the
initial spinning of the gyroscope may be a rechargeable battery
that can be recharged by the generated electricity. Therefore,
under this particular design, a gyroscope-based generator may be a
self-powered, autonomous system when the spinning gyroscope, the
precession of the gyroscope and the oscillating motion are in
phase and in resonance with one another.  
  
In other implementations, gyroscope-based generators based on the
present combined operation of the spinning gyroscope and the
coupling mechanism may be configured to initiate the spinning of
the gyroscope without using energy from a power supply. The
oscillating motion caused by a suitable source such as the ocean
waves or winds can be used to cause the coupling mechanism to
rotate the rotary electromagnetic motor generator to generate the
electricity. This electricity is then used to spin up the
gyroscope until the spinning gyroscope, the precession of the
gyroscope and the oscillating motion are in phase and in resonance
with one another. After this initial spin-up of the gyroscope, a
part of the generated electricity is used to sustain the spinning
of the gyroscope while the remaining part of the generated
electricity is used to drive an electric load or to be stored in a
storage device.  
  
FIG. 1 illustrates one example of a gyroscope-based generator 100
described in this application. A platform or base member 140 is
provided to interact with an oscillating object or an oscillating
force and to support a gyroscope 110 and an electromagnetic rotary
motor generator 130. The oscillating motion of the platform or
base member 140 causes an oscillating torque to be applied to the
spinning gyroscope 110 and thus maintains the precession of the
gyroscope 110. When the gyroscope 110 spins around its own
spinning axis, the oscillating torque acts on the gyroscope 110 as
an external torque and causes the gyroscope 110 to precess. A
coupling mechanism 120, e.g., a mechanical transmission or
coupler, is coupled between the precessing gyroscope 110 and the
rotary motor 130 to transfer the precession of the gyroscope 110
to the rotation of the rotary motor 130. The rotation energy of
the rotary motor 130 is converted into electricity.  
  
FIG. 2 illustrates the energy conversion in the gyroscope
generator 100. The oscillating motion of the platform 140 and the
spinning motion of the gyroscope 110 are coupled to each other to
cause precession of the spinning gyroscope 110. This coupling
essentially converts the energy of the oscillating motion of the
platform 140 into the energy of the precession of the spinning
gyroscope 110. The precession of the spinning gyroscope 110 is
then converted by the coupling mechanism 120 into a continuous
rotation of the rotary motor 130 which produces the electricity
energy from the rotation. The generated electricity is then used
to power a load or device or is stored in a rechargeable battery.
As illustrated, a portion of the generated electricity may be used
to power and maintain the spinning of the gyroscope 110.  
  
FIG. 3 shows a simple gyroscope 110 that may be used in the device
100 in FIG. 1. The gyroscope 110 operates based on the Newton's
principle that a massive rapidly spinning body rigidly resists
perturbation and reacts to a disturbing torque by precessing or
rotating slowly around a precession axis orthogonal to the axis of
the disturbing torque and the axis of the gyroscope's spin vector.
As illustrated, the angular momentum of the gyroscope 110 can be
represented by a vector (Li) along the axis of the spinning
rotation. When the angle ([theta]) of the gyroscope 110 changes
due to an external disturbing torque, the angular momentum vector
changes. While the magnitude of the angular momentum (L) is
constant, the initial angular momentum (Li) and the final angular
momentum (Lf) differ. Thus, due to the conservation of angular
momentum, a resultant angular momentum vector (N) is introduced
and the sum of N and Lf is equal to Li.  
  
The change in the component of N, (Np), oriented along the axis of
precession, which is the crank arm axis in an example described
below, is ||Np||=L sin([theta]) for one quarter of a full cycle.
Because Np is the change in Li that contributes to the torque
turning the crank arm of the device 100, and the average torque  
  
[mathematical formula - see original document]  
  
can be expressed as follows:  
  
[tau]=4Lf sin([theta]),  
  
where f is the frequency of the oscillating object or force such
as ocean waves. Thus the theoretical input power from the torque
caused by the oscillating object or force is:  
  
Pin=8[pi]f<2> L sin [theta].  
  
As an example, consider an implementation of the design in FIG. 1
where a crank arm is used as the coupling mechanism 120 between
the gyroscope 110 and the rotary motor 130. If the gyroscope 110
spins at a gyro rate of 90 r.p.s. and the frequency of the wave
stimulator which simulates ocean waves to rock the device 100 is
1.25 Hz, the gyroscope generator 100 in FIG. 1 can generate 0.817
W of electricity for a wave angle of 20[deg.] and a crank arm of a
radius at 0.1 meter.  
  
FIG. 4 illustrates one exemplary implementation of the gyroscope
generator 400 based on the design in FIG. 1. The gyroscope
generator 400 includes a gyroscope 410 with a gyro wheel 412
driven by a gyro motor 418, a rotary motor generator 460, and a
crank arm 430 as part of the coupling mechanism to transfer the
precession of the gyroscope 410 to the rotation of the rotary
motor generator 460. The entire system is mounted on a base 480.  
  
The gyro wheel 412 of the gyroscope 410 is mounted to spin around
a gyro axle 414 that is substantially parallel to the crank arm
430 and to the base 480. The gyro axle 414 is engaged to and is
rotated by the gyro motor 418 to cause the gyro wheel 412 to spin.
A gyroscope power supply, such as a battery, may be used to supply
the electrical power to the gyro motor 418 for, at the minimum,
initiating the spin of the gyro wheel 412 so that the oscillating
motion of the base 408 can cause the gyroscope 410 to precess. A
gyro bracket 416 is structured to hold the gyro wheel 412, the
gyro axle 414, and the gyro motor 418 together as the assembled
gyroscope 410. A mechanical coupler or coupling element 420 may be
used to engage the gyro bracket 416 to the crank arm 430. In this
configuration, as the gyroscope 410 precesses in response to the
external oscillating motion exerted on the generator 400, the
precession motion of the gyroscope 410 causes the crank arm 430 to
rotate via the coupling element 420.  
  
The crank arm 430 in the illustrated example is engaged to a first
rotational axel 440 that is substantially perpendicular to the
crank arm 430 and the gyro axel 414. When the gyroscope 410
precesses, the crank arm 430 rotates around the axel 440 along
with the precession of the gyroscope 410. The crank arm 430 may be
configured in various geometries. For example, the crank arm 430
may be a circular plate with its center engaged to the axel 440 so
that the plate spins or rotates around the axel 440. The crank arm
439 includes a crank hub 432 that is engaged to the axel 440. The
gyroscope 410 may be positioned on the crank arm 430 off the first
axel 440, or alternatively, near or at the axel 440. The axel 440
may be the rotary axel of the rotary motor generator 460. In the
illustrated example, a pair of reduction gears 442 and 444 are
used to transfer the rotation of the axel 440 to the rotation of a
second, substantially parallel axel 450 which is the rotary axel
of the motor generator 460. The gear 442 is engaged to rotate with
the axel 440 and the gear 444 is engaged to rotate with the axel
450. The gears 442 and 444 are engaged to each other so their
rotary motions are synchronized and may be sized with different
diameters, e.g., the diameter of the gear 442 is greater than that
of the gear 444, to rotate the motor 460 at a higher angular
velocity than the axel 440. Therefore, in the illustrated example,
the combination of the crank arm 430, the axel 440, the pair of
reduction gears 442 and 444 forms the coupling mechanism 120 in
FIG. 1. Other suitable implementations of the coupling mechanism
120 may be used.  
  
The gyroscope generator 400 is further shown to use a generator
frame 490 on a bottom plate 482 to hold the motor 460, the
reduction gears 442 and 444, and the first axel 440. Electrical
connectors and circuits (e.g., rectifiers) 470 for the rotary
motor generator 460 may also be placed in the generator frame 470.
The bottom plate 482 may be directly engaged to the base 480.  
  
The gyroscope generator 400 may be adapted to interact with
various oscillating motions to generate electricity. For example,
the base 480 or an extension connected to the base 480 may be used
to interact with wind to cause the base 480 to oscillate with the
wind and to generate electricity. As another example, a floating
device or a buoy may be engaged to the base 408 and the entire
system can float on the ocean to generate electricity from the
oscillating motion of the ocean waves.  
  
FIG. 5 shows an example of a buoy gyroscope generator 500. A
waterproof chamber or housing 510 is provided to enclose the
generator 400 in FIG. 4. The housing 510  includes a buoy
hull 512 with a bottom 518 and a top opening that is sealed by a
lid 514. A Teflon gasket 516 and fasteners may be used to engage
the lid 514 to the top opening and to provide a waterproof seal.
The base 408 of the gyroscope generator 400 is fixed to the bottom
518 of the housing 510 to facilitate the energy transfer from the
motion of the waves to the motion of the housing 510. In
operation, the housing 510 floats on the water surface to keep the
bottom 518 and thus the base 408 to be parallel to the water
surface when the water is calm without waves. When waves are
present in the water, the up-and-down oscillating motion of the
waves causes the gyroscope generator 400 inside the housing 510 to
move accordingly with the waves and this motion of the gyroscope
generator 400 in turn causes the gyroscope 410 to precess and to
rotate the crank arm 430 which turns the rotary motor generator
460.  
  
The housing 510 may be engaged to a set of elongated plates or
blades, which extend vertically into the water, to provide lateral
stability of the housing 510 and to ensure that the bottom 518 of
the housing 510 faces downward. As illustrated in FIG. 5, a set of
radial keel blades 530, e.g., four blades, may be engaged to the
bottom portion of the housing 510 via keel attachments struts or
other suitable fasteners 520. These blades interact with water to
transfer the water wave motion into the motion of the housing 510.
Hence, the up and down circulating movement of the waves rocks the
housing 510 and causes the precession of the gyroscope 410 inside
the housing 510. In addition, additional weights 540 may be
attached to the bottom side of the housing 510 to further
stabilize the system in the upright position.  
  
In the designs shown in FIGS. 4 and 5, the angular momentum of the
gyroscope 410 can be computed by L=I[omega], where I is the moment
of inertia of the gyro wheel, and [omega] is the spinning angular
velocity of the gyroscope. As an example, if the gyro wheel of the
gyroscope 410 is a ring, the moment of the ring is given by:  
  
[mathematical formula - see original document]  
  
where M1 is the projected mass of a disk with the outer radius of
the ring, and M2 is the projected mass of a disk with the inner
radius of the ring, and r1 and r2 are the outer and inner radii,
respectively.  
  
Consider a specific configuration for the above example as
follows:  
  
M=0.47 [kg],  
r1=0.046 [m],  
r2=0.03 [m],  
M/m<2> =123.031 [kg/m<2> ],  
M1=0.817862 [kg] and  
M2=0.347862 [kg],  
  
The moment is I=0.000709 [kg.m<2> ], the angular momentum
is  L=I[omega]=0.400794 [kg.m<2> [omega]] and the input
power for spinning the gyroscope is Pin=8[pi]f<2 > L
sin([theta])=5.383 [W]. The gyroscope 410 in the designs shown in
FIGS. 4 and 5 is offset to the crank arm axis 440 so that there is
a small addition of power from the potential energy of the height
of the gyroscope 410 due to gravity introduced every cycle. This
part of the contribution can be expressed by Pgravity=4rMg
sin([theta])f, where g is the acceleration of gravity. For the
specific numbers used above, Pgravity=0.788 [W]. Accordingly, the
total input power to the system is 6.171 [W]. In a simplified
testing prototype generator based on the above numbers, the
measured electrical load power Pload is 0.817 W. Therefore, the
efficiency of the prototype generator, Pload/Pin, is 0.817
[W]/6.171 [W]=0.132, or 13.2%.  
  
FIGS. 6A and 6B illustrate exemplary circuits for the rotary motor
generator and the driver circuit for the gyro motor that spins the
gyroscope, respectively, in a simplified testing prototype. In
this example, a gyro power supply such as a battery is provided to
supply the electrical power to initially spin up the gyroscope. A
tri-axial accelerometer is used to measure the motion of the
prototype platform. An oscilloscope is used to measure the rate of
rotation of the gyroscope. The motor-generator energizes the test
load and can be switched to provide power to the gyroscope motor
in FIG. 6B. A data recorder records the accelerometer and
generator outputs.  
  
The designs in FIGS. 4 and 5 may be configured with the capability
to resonate at different wave frequencies under simple controls.
The system resonates when the wave frequency and the gyroscopic
precession frequency are the same or are sufficiently close to
each other to be in resonance with each other. This resonant
condition occurs when the torque that the gyroscope 410 exerts on
the generator crank arm 430 with respect to the crank arm axis is
equal but opposite to the torque the generator 400 exerts on the
gyroscope 410. Under the resonance condition, the ratio between
torque and angular momentum can be expressed as  
  
[tau]/L=4f sin([theta]).  
  
As long as this ratio is maintained during operation, the device
can resonate at any given wave frequency and angle.  
  
A simple prototype, Gyro-Gen, based on the designs in FIGS. 4 and
5 was successfully built and tested. The main components of this
prototype are a gyroscope (adapted from a Sony capstan flywheel,
shaft, and bearing set), a gyro motor with 9V DC and 20 ohms
impedance, a crank arm made of a 1.27\*28.3 cm aluminum rod, an
electric generator (adapted from a 4-phase synchronous motor
Superior Electric model MD62-FC09/1.7 V/4.7 A/65 oz.in torque), a
control circuit (10A Schottky diode rectifiers), and a housing.
The gyroscope is attached to a crank arm so that the torque
generated is perpendicular to the change in angle due to the
buoyant wave force on the hull. The spinning gyro's angular
velocity is electronically varied to change the precessional
torque on the crank arm in order to adapt the device to different
wave frequencies. In various tests conducted in the prototype,
frictional and electrical losses were minimized by using low
friction bearings for the gyro, matching the electric generator's
impedance to the load, and using Schottky diodes for the
rectifiers.  
  
In testing the prototype Gyro-Gen, a motion controlled test frame
was built as a wave simulator to simulate the rocking motion of
the device when floated on the ocean. The test frame includes a
brushless torque motor and programmed to simulate [2/3] to
4-second period ocean waves. An 8-channel data recorder
(Persistor, Inc. CF2) was mounted on the test frame to record 20
samples per second electrical output power and output of a 3-axis
accelerometer (Crossbow CXL04LP3) mounted below the crank arm
shaft. Data analysis software was written using Matlab.  
  
The Gyro-Gen was tested with varying wave periods, fixing tilt,
electrical load, gyro rate, and crank arm offset to obtain
measures of the output power as a function of the angular
velocity. The gyro spinning rate was varied by 20 r.p.s. between
successive runs. Before each run, the gyro was spun up by applying
a constant voltage to the gyro motor from a lab power supply
(Tektronix PS280). The gyro spinning rate was determined using the
back e.m.f. frequency of the gyro motor recorded with a Tektronix
THS 730A digital storage oscilloscope. The load impedance was
measured with the Fluke 87 DMM. The electrical generator's load
impedance was set to 100 ohms. During the run wave frequencies
were held constant for 30 seconds before stepping in 0.25 Hz.
increments until the maximum frequency of 1.5 Hz was reached. Then
the wave frequency was stepped down in 0.25 Hz increments until
the minimum of 0.25 Hz. was reached marking the end of the run.
Each run was performed 3 times.  
  
Measurements of the generated power as a function of the
electrical load were also obtained by decreasing the load
impedance from the initial value of 100 ohms to 50 ohms and 33
ohms and gyro angular velocities set to 65 and 90 r.p.s.  
  
A Maximum Load Test was conducted (at the previous range of wave
frequencies and gyro rates) in which the load was increased using
a 100 watt Ohmite rheostat until the crank arm stopped rotating
synchronously, then decreased just enough to restore synchronous
rotation. Under this condition, the voltage generated and the
final load impedance were recorded using an averaging D.M.M. Then
the power was calculated to determine the maximum power the system
could generate at a specific gyro rate and a specific wave
frequency.  
  
Another bench test, Self-Powered Gyro Test, was conducted with the
Gyro-Gen  operating autonomously by using the generated power
to spin the gyroscope. The gyro was initially spun by the bench
power supply at 80 r.p.s. The gyro motor was then switched to the
electric generator, which was also loaded with 100 ohms and driven
by the test frame at 1.5 Hz wave frequencies until the gyro rate
was stabilized. The wave frequency was decreased to 1.25 Hz and
the gyro's angular velocity was again allowed to stabilize.  
  
FIGS. 7A, 7B, 8A, 8B, and 9 show power measurements of the
prototype Gyro-Gen with the test frame. FIG. 7A shows the power
measurements as a function of the angular velocity of the
gyroscope. According to the measurements, when the gyro rate was
set to zero, the crank arm failed to make a complete revolution
and to synchronize with the wave period simulated by the test
frame. When the gyro's angular velocity was increased to 20 r.p.s.
the crank arm began to move, but only made partial revolutions at
1.25 and 1.5 Hz waves and did not resonate. When the gyro's rate
was increased to 40 r.p.s. and the wave frequency step was 1.0 Hz,
the crank arm started to make continuous revolutions and became
phase-locked with the wave motion. The generator made continuous
revolutions at 1.0, 1.25, and 1.5 Hz waves. At 65 r.p.s. the
Gyro-Gen synchronized at all frequencies except 0.25 Hz; at 90
r.p.s., the crank arm phase locked at all wave frequencies. The
data indicates that there is a direct relationship between the
gyro rate and the ability of the generator to output power.  
  
FIG. 7B shows calculated theoretical power using the same
parameters as tested for the  prototype Gyro-Gen. The
calculated results are consistent with the measured results after
the losses are accounted for.  
  
FIG. 8A shows power measurements as a function of the load. When
the gyroscope was spinning at both 65 and 90 r.p.s., the increase
in load, though dropping the voltage, increased the power output.
When the load was increased to 33 ohms, the power output increased
for all wave frequencies except 0.5 and 0.25. Results show that
there is an optimal electrical impedance that should be matched to
the mechanical impedance. This optimal electrical impedance can be
determined by the gyro rate, the buoyant force and the wave
frequency. To test this, a maximum load test was conducted and
FIG. 8B shows the results. Comparing data in FIG. 7A to the same
test conducted at "maximum load" in FIG. 8B, the power generated
was substantially increased. For example, at a 90 r.p.s. gyro rate
with a 1.25 Hz wave frequency, the power output at a fixed load of
100 ohms was less than 0.7 watts, whereas at "maximum load" of 6.3
ohms, the output was 3.0 watts, greater than a 400 percent
increase in power. Similar large increases were observed at all
gyro rates above 20 r.p.s. At a wave frequency of 1.25 Hz, the
power levels off as the load approaches the source impedance of
the generator. The 1.5 Hz frequency was not recorded because the
output power went beyond the range of the stepper motor generator.
These results indicate that for the practical
wave-powered-generator, a controllable gyro rate and electrical
load can be used to adapt to different wave frequencies to improve
the conversion efficiency.  
  
The efficiency of the system can be estimated by dividing the net
power (maximum power generated minus the gyro motor power) by the
total power at maximum output and adding all measurable system
losses. For example, at 90 r.p.s. and 1.25 Hz, the power output of
gyro motor plus load was 2.98 watts. The gyro motor power was 2.16
watts, so that the net output power was 0.817 watts. Adding the
total losses, the diode bridge loss was 1.13 watts and the
generator's internal resistance loss was 1.042 watts. The total
measured power dissipation equals 5.122 watts. This compares well
with the theoretical total power input of 6.17 watts. The
corresponding efficiency is 0.817 watts/5.12 watts, or 16%. Using
the theoretical power input instead of the measured power output
the efficiency is 13%. Noting losses in the diode bridges, the
rectifiers were replaced with Schottky diodes and efficiency
increased to 18.4%.  
  
FIG. 9 shows that after the initial rate of 80 r.p.s, driven at a
wave frequency of 1.5 Hz, the gyro's angular velocity decreased,
then stabilized, with the crank arm rotating synchronously, thus
the generator was able to continuously power both the load and the
gyro motor. When the wave frequency was stepped down to 1.25 Hz,
the same results occurred. At 1.0 Hz the output was insufficient
to sustain the gyro and the system eventually stopped. Results
indicate that when the gyro motor was powered by the generator
output, the system became self-sustaining, converting enough
energy to maintain the gyro rotation while powering an auxiliary
load.  
  
The above Gyro-Gen as mounted in a watertight (60.6 liter
Rubbermaid Roughneck) utility tub to form a prototype based on the
design in FIG. 5 for conducting sea tests. The utility tub was
used as the housing 510 and was made watertight with a Plexiglas
disk sealed with Teflon gasket. The Plexiglas disk was 0.56 cm
thick and 54.6 cm in diameter. The buoy was ballasted with 3.4 kg
dumbbell weights and 25.4 cm Unistrut(R) brackets in a radial keel
configuration were installed on the utility tub to maximize wave
power input to the hull. A data recorder was installed and
acceleration and voltage recorded at 10 samples per second at
constant gyro speed and electrical load. Measurements under
various operating conditions are called "Runs" in this
specification. For Run 1, four brackets were as keels, in Run 2
one bracket was used along with the 3.4 kg weight, in Runs 3-7
four bracket keels and 3.4 kg ballast were used. Gyro angles for
Runs 3-7 ranged from 90 to 0 degrees in 30 degree increments used
the standard settings of 10 cm crank arm.  
  
Ocean testing included seven test runs shown in FIG. 10. In the
first three tests, the keel design and ballast were varied and the
best results were observed with 4 Unistrut bracket keels and 3.4
kilos (7.5 lb) ballast. This set up was kept throughout all
remaining runs (FIG. 12). Run 3, with the standard settings of 10
cm crank arm radius and 90 degree angle gyro, generated the most
power of any sea tests. Run 7 (gyro angle at 0.0 degrees)
generated the least power of the runs performed with the gyro on.
Run 6 (gyro off) revealed far lower power output than any other
run. For example, in Run 3, with the optimal keel design, the
output was more than ten times greater with the gyro rotating than
when stopped. The contrast in power output between runs with and
without the gyro rotating suggests that precessional torque
converts periodic wave energy into the rotary motion of the crank
arm.  
  
The above test results demonstrate that power generation based on
gyroscopic precession is a viable technology for an autonomous
wave-powered generator. The prototype Gyro-Gen successfully
generated sufficient power to run both the gyroscope and an
auxiliary load. Hence, the gyroscope can be used to efficiently
transfer power from periodic angular motion into electricity. The
test results further show that the crank arm could generate little
power without the gyro's precessional torque. As the angular
momentum of the gyroscope increases, the amount of the potential
torque to the generator and the electrical power output increase
accordingly. Notably, the load can be controlled in order to
achieve the maximum power output. Both experimental and
theoretical results indicate that the electrical load and the
angular momentum of the gyro are interrelated, i.e., if the
angular momentum on the gyro is increased, it only helps to a
certain point before the load must be increased. For instance, as
indicated in FIG. 7A, the power output started to level off at 40
r.p.s. for frequencies of 1.0 Hz and above, and at 60 to 65 r.p.s.
for wave frequencies of 0.25 Hz to 0.75 Hz. In FIG. 8B, power
outputs at all wave frequencies continued to increase with the
gyro angular velocity. A maximum of 3.0 watts into a 6.3-ohm load
was generated at a wave frequency of 1.25 Hz and a gyro rate of 90
r.p.s. Efficiency calculations show that it is important to keep
electrical and frictional losses as low as possible.  
  
Sea tests of the prototype Gyro-Gen show that a rotating gyro
increased the power output significantly. The buoy design in FIG.
5 was effective and efficient in converting the wave energy into
electricity. In particular, the addition of the radial-blade keel
and ballast configuration resulted in higher output. Independent
sea-state data at the same time and location of the tests
indicated the significant wave height was approximately 0.5 meter
at a period of approximately 12 seconds. See, Coastal Data
Information Program, Integrative Oceanography Division, Scripps
Institution of Oceanography, "Energy Spectrum Monthly Plot: 073
Scripps Pier," [Online document] (March 2004), Available HTTP:
http://cdip.ucsd.edu/?nav=historic&stn=073&stream=p1&sub=data&xyrmo=200403&xitem=product8.
Although the wave period was beyond the range of the prototype,
the results still support the conclusion that gyroscopic
precession increases power output.  
  
The present gyroscope-based generator may be implemented in a
large scale to increase the power output. As an example, assume a
gyroscope with a moment of inertia of about 30 [kg.m<2> ] is
used. This is approximately equivalent to the moment of inertia of
a 250 [kg] disk with a radius of 0.5 [m]) spinning at 200 [r.p.s].
The angular momentum of this large gyroscope is approximately 3600
[kg.m<2> .[omega]]. Thus a Gyro-Gen buoy containing a single
gyroscope mechanism with the above large gyroscope can generate
approximately 2340 Watts in little more than one cubic meter of
space excluding the buoy hull assuming the buoy pitches at +-15
degrees on a 10 second period wave. Therefore, depending on the
power requirements, gyroscope-based generators may be sized to
provide sufficient power outputs for different applications.  
  
FIG. 11A further shows a block diagram of an exemplary
gyroscope-based generator 1100 that implements a system controller
1130 and a power regulator 1150. The power regulator 1150 is
connected to receive generated electrical power from the
electrical generator 130. A regulation signal 1152 is sent to the
system controller 1130 to inform the system controller of the
status of the regulator load. A gyro angular velocity sensor 1120
is coupled to the gyro wheel of the gyroscope 110 to measure the
angular velocity. The measured angular velocity is fed to the
system controller 1130. In addition, one or more motion sensors
1140 for measuring the pitch, roll, and heave parameters of the
whole system caused by the periodic or oscillating torque that
acts on the gyroscope 110 and possibly the transmission 120. The
measurements from the one or more sensors 1140 are sent to the
system controller 1130.  
  
The system controller 1130 processes the measurements from the
sensors 1120 and 1140 and the load information from the power
regulator 1150 and dynamically controls the angular velocity of
the gyroscope 110 by producing a gyro motor velocity control
signal. A gyro motor velocity control unit 1110 is provided to
respond to the control signal and to control the gyro motor 418
accordingly. The gyro motor 418, in turn, drives the gyroscope 110
at a desired gyro angular velocity. Hence, this control feedback
is dynamic in the sense that the gyro angular velocity is adjusted
with changes in the external periodic torque and the load. The
power regulator 1150 splits the power from the generator 130 into
a first portion as the output for distribution, e.g., driving an
electronic device or an electrical appliance, and a second portion
to a storage battery 1160. The storage battery may be used as the
power supply for the gyro motor 418.  
  
FIG. 11B shows another implementation based on the design in FIG.
11A where a crank arm angle sensor is used to measure the angle of
the crank arm and feeds the angle measurement to the system
controller 1130. The system controller 1130 can process and use
this information, in addition to other information (e.g., gyro
angular velocity and the buoy motion parameters), to control the
velocity of the gyro motor and thus the spinning speed of the
gyroscope.  
  
FIG. 12 shows an exemplary operation of the system controller 1130
in the device 1100 as a buoyant system. First, the system is
initialized at step 1210 to, e.g., power up the gyroscope and
check communications with different parts of the systems such as
the sensors. At step 1220, the attitude measurements from the
sensors 1140 are acquired by the system controller 1130. At step
1230, the buoy dynamics is computed to determine the power input
from the external periodic torque. The system controller 1130 sets
the initial gyro angular velocity and power output regulator to
match the power input. This is the step 1240. At this time, the
generator 130 begins to generate electricity (step 1250). The
system controller 1130 further acquires attitude measurements from
sensors 1140 to extract the buoy pitch and roll angles (step 1260
and 1270). At step 1280, the system controller 1130 determines
whether the pitch, roll, and crank arm precession angle are in
phase with each other. The regulator load is adjusted to increase
or decrease in order to maintain the phase between the pitch,
roll, and crank arm precession angle. If the pitch and roll are
not synchronized, the system initialization and subsequent steps
are performed get the system back to the "normal" operation.  
  
In the above examples, only a single gyroscope is used in a
gyroscope-based generator. In other implementations, two or more
gyroscopes may be used in a generator to achieve certain operating
advantages. FIG. 13 shows one example of a gyroscope-based
generator 1300 where two gyroscopes 1310 and 1320 are used. The
first gyroscope 1310 is fixed to a transmission gear 1312 which
may be a circular plate or a cylinder with a geared edge. The
precession of the gyroscope 1310 causes the transmission gear 1312
to rotate with the precession. Similarly, the second gyroscope
1320 is fixed to a second transmission gear 1322 which may be a
circular plate or a cylinder with a geared edge. The precession of
the gyroscope 1320 causes the transmission gear 1322 to rotate
with the precession. The two transmission gears 1312 and 1322 are
engaged at their geared edges to rotate in opposite directions and
are synchronized with each other. Two electric motor-generators
1316 and 1326 are respectively engaged to the transmission gears
1312 and 1322 and are driven to produce electricity. As
illustrated, gears 1314 and 1324 are used to engage the
transmission gears 1312 and 1322 to the rotary motor-generators
1316 and 1326, respectively. The control mechanism described in
FIGS. 11 and 12 may be applied to the dual-gyroscope generator
1300. A common base 1301 is used to support both gyroscopes and to
cause both gyroscopes to react to the same oscillating motion.  
  
In summary, only a few implementations are disclosed. However, it
is understood that variations and enhancements may be made.  
  


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