U.S. patent application number 14/542215 was filed with the patent office on 2015-03-05 for method of harvesting energy from exercise equipment.
This patent application is currently assigned to STRENGTH COMPANION, LLC. The applicant listed for this patent is DAVID G. OTEMAN. Invention is credited to DAVID G. OTEMAN.
Application Number | 20150065301 14/542215 |
Document ID | / |
Family ID | 51870065 |
Filed Date | 2015-03-05 |
United States Patent
Application |
20150065301 |
Kind Code |
A1 |
OTEMAN; DAVID G. |
March 5, 2015 |
Method of Harvesting Energy from Exercise Equipment
Abstract
Electricity is generated in response to use of exercise
equipment in a reciprocating motion. An energy harvester system is
provided in and responsive to movement of a motion control
arrangement of an exercise machine for converting kinetic and
ambient light energy supplied from an environment of the exercise
equipment into electrical power which is delivered to a feedback
system associated with the exercise equipment in order to provide
information corresponding to the user of the exercise
equipment.
Inventors: |
OTEMAN; DAVID G.;
(DELAFIELD, WI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OTEMAN; DAVID G. |
DELAFIELD |
WI |
US |
|
|
Assignee: |
STRENGTH COMPANION, LLC
DELAFIELD
WI
|
Family ID: |
51870065 |
Appl. No.: |
14/542215 |
Filed: |
November 14, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13282046 |
Oct 26, 2011 |
8888660 |
|
|
14542215 |
|
|
|
|
61409122 |
Nov 2, 2010 |
|
|
|
Current U.S.
Class: |
482/2 |
Current CPC
Class: |
A63B 23/03533 20130101;
H02J 1/12 20130101; A63B 21/0055 20151001; A63B 23/03541 20130101;
A63B 21/005 20130101; A63B 21/0628 20151001; A63B 71/0622 20130101;
A63B 21/4043 20151001; A63B 21/152 20130101; A63B 21/4035 20151001;
A63B 21/0053 20130101 |
Class at
Publication: |
482/2 |
International
Class: |
A63B 21/005 20060101
A63B021/005; A63B 21/00 20060101 A63B021/00; H02J 1/12 20060101
H02J001/12; A63B 23/035 20060101 A63B023/035 |
Claims
1. A method comprising the steps of: generating a DC link voltage
as a result of rotating a shaft of an electricity generator in two
directions, wherein the generator shaft is rotated in both of the
two directions as a result of a reciprocating motion of a user of
exercise equipment.
2. A method according to claim 1, wherein the DC link voltage
fluctuates during the reciprocating motion.
3. A method according to claim 2, further comprising the step of
clamping the DC link voltage.
4. A method according to claim 3, further comprising the step of
converting the DC link voltage to a DC output voltage having a
generally constant average value.
5. A method according to claim 4, further comprising the step of
delivering the DC output voltage to a feedback system associated
with the exercise equipment.
6. A method comprising the steps of: generating a DC link voltage
having a varying amplitude, wherein the generating step is caused
by a single repetition of a reciprocating motion of a user of
exercise equipment, and wherein the varying amplitude has a
plurality of maximum amplitudes.
7. A method according to claim 6, further comprising the step of
clamping the DC link voltage.
8. A method according to claim 7, further comprising the step of
converting the DC link voltage to a DC output voltage having a
generally constant average value.
9. A method according to claim 8, further comprising the step of
delivering the DC output voltage to a feedback system associated
with the exercise equipment.
10. A method according to claim 6, wherein the plurality of maximum
amplitudes are separated by a time period of lower amplitude.
11. A method of producing and utilizing electrical power in
exercise equipment having a motion control at moveable in repeating
cycles of movement along a reciprocating motion path, the method
comprising the steps of: converting kinetic energy created due to
the reciprocating movement of the motion control arrangement of the
exercise equipment into a variable electrical power output
utilizing a generator assembly, wherein the variable electrical
power output is dependent upon a velocity of movement of the motion
control arrangement along the reciprocating motion path; converting
the variable electrical power from the generator assembly into a DC
link voltage; clamping the DC link voltage if the velocity of
movement of the motion control arrangement exceeds a threshold;
converting the DC link voltage into a DC output voltage having a
generally constant average value; and delivering the DC output
voltage resulting from the converted kinetic energy to a feedback
system associated with the exercise equipment, wherein the DC
output voltage powers the feedback system such that the feedback
system provides information related to use of the exercise
equipment.
12. The method of claim 11 wherein the generally constant average
value of the DC output voltage is independent from the
instantaneous velocity of movement of the motion control
arrangement.
13. The method of claim 11 wherein the DC link voltage is
controlled such that the DC link voltage varies during each cycle
of movement and has a generally constant average over one or more
cycles of movement of the motion control arrangement.
Description
RELATED APPLICATION
[0001] This application is a divisional application of co-pending
U.S. Patent Application Ser. No. 13/282,046, filed 26 Oct. 2011,
and entitled "Energy Harvester For Exercise Equipment," which
claims the benefit of U.S. Provisional Patent Application Ser. No.
61/409,122, filed 2 Nov. 2010, both of which are incorporated
herein by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] The present disclosure relates generally to exercise
equipment and, more specifically, pertains to strength training
equipment that functions using one or more rotating members to
independently power an electrical system that is part of the
equipment.
[0003] Modern cardiovascular fitness equipment, such as treadmills
and elliptical machines typically include a system of displaying
exercise metrics and cardiovascular performance feedback to the
user of the equipment. These systems have generally been called
fitness feedback systems. This type of feedback is generally
accomplished via an LED or LCD screen and provides the user
real-time data as well as workout summary information. This type of
feedback display system is standard and pervasive and has become a
consumer expectation.
[0004] In a typical fitness gym layout, a section of the facility
will be dedicated to cardiovascular equipment which is normally
powered by an external source. The cardiovascular machines are
generally arranged in parallel rows, facing televisions or may even
have an integrated television screen. The equipment will generally
plug into 120 VAC or 240 VAC outlets in the United States. In a
facility that was purpose-built for fitness, an electrical
infrastructure can be designed to make it convenient to plug in the
cardiovascular equipment. In many gym facilities, the routing of
electricity to the machines must be accomplished retroactively and
can lead to costly and unsightly electrical infrastructure.
[0005] Though less common, some cardiovascular equipment such as
certain stationary cycle designs, have successfully harnessed the
energy input of the user (human-powered). This allows for a degree
of freedom in the layout of the fitness gym because the equipment
need not be in close proximity to an electrical outlet. Another
advantage is that, especially in gyms with many machines, the
human-powered machines can reduce facility electricity costs
because the equipment does not draw power from the electric
utility.
[0006] In contrast to the cardiovascular equipment described above,
modern strength machines generally lack an analogous strength
performance or fitness feedback display system. There is, however,
lust as pronounced a consumer need as in the cardiovascular market
to have the experience of performance feedback on strength training
equipment. Users of strength equipment can utilize a feedback
system to further improve their strength conditioning, and more
precisely meet their strength training goals when compared with
using equipment that does not have a feedback or reporting
system.
[0007] Several factors have limited the adoption of such a fitness
feedback display system in strength equipment. A significant factor
is related to the practical problem of routing electricity to such
a system. The equipment layout requirements in the weight/strength
training areas of a fitness gym are substantially different than in
the cardiovascular areas. Some key reasons driving these
differences are summarized below:
[0008] 1. Strength training areas do not use the same or even
similar type of equipment as in the card to areas. There are
different types of strength equipment for each muscle group of the
human body. In addition, many gyms will provide two different
manufacturers of strength equipment to better meet the varied
preferences of their members. Each of these machines requires a
different footprint of floor area, and has a different entry access
requirement, e.g. side, front, rear for the user of the equipment.
As a result, it is virtually impossible to design an electrical
outlet infrastructure ahead of time to conveniently support the
necessary mix of strength machines in the gym.
[0009] 2. As gyms adopt new and improved equipment to satisfy their
customers, a previous electrical infrastructure will be very
unlikely to conveniently support the new equipment types, and is
not a constraint that the gym manager wants to address.
[0010] 3. Strength workout areas require users of the equipment to
access the equipment from multiple directions. In addition,
exercisers in a strength area often walk between machines to access
other areas of the gym. As a result, running electrical cords to
outlets on the floor pose a significant tripping hazard to the
users and/or require a highly inconvenient equipment layout to
avoid such hazards.
[0011] 4. Strength equipment has a tendency to move on the floor
over time. This is due to the necessary reaction forces taken
through the floor mounts, which arise naturally through the normal
use of equipment. These slight, but persistent movements, would be
problematic for ensuring that the equipment does not become
unplugged, or create an electrical hazard.
[0012] For these reasons, it is desirable for strength equipment
with a performance feedback and display system to avoid the use of
the gym facility electrical outlet and outlets.
[0013] Methods of eliminating the external power requirement for
exercise feedback systems, i.e., strength performance feedback
system, in strength equipment have not been widely adopted in
modern equipment. Batteries have been used to a limited extent as a
means of powering a fitness feedback system or a repetition
counter. Batteries are problematic because the functionality of the
fitness feedback system must be reduced such that the electronics
require sufficiently low power to accommodate a reasonable battery
life. An additional disadvantage of batteries is the required
operating cost due to the need for the batteries to be replaced
and/or recharged.
SUMMARY OF THE INVENTION
[0014] An embodiment of a method according to the present invention
includes the step of generating a DC link voltage as a result of
rotating a shaft of an electricity generator in two directions,
wherein the generator shaft is rotated in both of the two
directions as a result of a reciprocating motion of a user of
exercise equipment.
[0015] According to one aspect of a method according to the present
invention, the DC link voltage fluctuates during the reciprocating
motion.
[0016] An embodiment of a method according to the present invention
may include the step of generating a DC link voltage having a
varying amplitude, which may be clamped, wherein the generating
step is caused by a single repetition of a reciprocating motion of
a user of exercise equipment, and wherein the varying amplitude has
a plurality of maximum amplitudes.
[0017] According to yet another aspect of a method according to the
present invention, the plurality of maximum amplitudes may be
separated by a time period of lower amplitude.
[0018] According to yet another aspect of a method according to the
present invention, the method may further include the step of
converting the DC link voltage to a DC output voltage having a
generally constant average value. The DC output voltage may be
delivered to a feedback system associated with the exercise
equipment.
[0019] An embodiment of a method according to the present invention
relates to producing and utilizing electrical power in exercise
equipment having a motion control arrangement moveable in repeating
cycles of movement along a reciprocating motion path. This
embodiment may include the steps of (a) converting kinetic energy
created due to the reciprocating movement of the motion control
arrangement of the exercise equipment to a variable electrical
power output utilizing a generator assembly; and (b) converting the
variable electrical power from the generator assembly into a DC
link voltage. The variable electrical power output may be dependent
upon a velocity of movement of the motion control arrangement along
the reciprocating motion path. Additionally, the DC link voltage
may be clamped if the velocity of movement of the motion control
arrangement exceeds a threshold, and the DC link voltage may be
converted into a DC output voltage having a generally constant
average value. The DC output voltage may be delivered to a feedback
system associated with the exercise equipment, wherein the feedback
system may provide information related to use of the exercise
equipment.
[0020] According to an aspect of a method according to the present
invention, the generally constant average value of the DC output
voltage may be independent from the instantaneous velocity of
movement of the motion control arrangement.
[0021] According to another aspect of a method according to the
present invention, the DC link voltage may be controlled such that
the DC link voltage varies during each cycle or repetition of
movement and has a generally constant average over one or more
cycles of movement of the motion control arrangement.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1A illustrates a perspective view of exercise equipment
having an energy harvester system according to the present
disclosure;
[0023] FIG. 1B illustrates a rear view of the exercise equipment
depicted in FIG. 1A;
[0024] FIG. 2A illustrates a front view of a pulley generator
assembly having an electrical generator, a high speed pulley, a
coupling belt, and a low speed pulley that is used in the energy
harvester system with the exercise equipment of 1A;
[0025] FIG. 2B illustrates a side view of the pulley generator
assembly of FIG. 2A;
[0026] FIG. 2C illustrates a view of the pulley generator assembly
of FIG. 2A utilized with a low speed pulley connecting a weight
stack cable or belt at a 90 degree angle;
[0027] FIG. 2D illustrates a view of the pulley generator assembly
of FIG. 2A utilized with a low speed pulley connecting a weight
stack cable or belt at a 180 degree angle;
[0028] FIG. 2E illustrates a view of a gear generator assembly
connecting a weight stack cable or belt at a 90 degree angle;
[0029] FIG. 3A illustrates a front view of an exemplary console for
displaying exercise related information, having an integrated
photovoltaic array as part of a system for the energy harvester
system;
[0030] FIG. 3B illustrates a side view of the console of FIG.
3A;
[0031] FIG. 4A is a block diagram illustrating the components and
interfaces of control electronics for the energy harvester
system;
[0032] FIG. 4B is a block diagram illustrating an alternative
embodiment of FIG. 4A showing the photovoltaic energy harvester
with an MPPT apparatus;
[0033] FIG. 4C is a block diagram similar to FIG. 4A showing the
control electronics provided with overvoltage protection;
[0034] FIG. 5A illustrates corresponding three phase output
voltages of the pulley generator assembly depicted in FIG. 2A, when
the pulleys of FIG. 2A are in motion at a constant speed; and,
[0035] FIG. 5B illustrates the motion and corresponding electrical
signals of the control electronics depicted in the block diagram of
FIG. 4A, when a user performs a repetition using the exercise
equipment of FIG. 1A.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0036] Although the disclosure hereof is detailed and exact to
enable those skilled in the art to practice the invention, the
physical embodiments herein disclosed merely exemplify the
invention which may be embodied in other specific structures. While
the preferred embodiment has been described, the details may be
changed without departing from the invention, which is defined by
the claims.
[0037] The present disclosure relates to an energy harvester system
for use with an exercise device. In particular, the energy
harvester system produces output power which is suitable for an
electronics load that can be used in strength training equipment,
including, but not limited to, LCD and LED displays,
microcontrollers, memory devices, sensors and wireless
communication electronics. A typical use of electronics and
strength exercise equipment is for a fitness feedback system. The
energy harvester system relies on two modes of operation. In the
first mode (kinetic harvesting mode), the energy harvester system
converts kinetic energy due to the motion of the exercise equipment
into electrical energy. In the second mode (the standby harvesting
mode), the energy harvester system converts energy from the
environment, such as the energy in the ambient-radiated light, into
electrical energy. The two nodes may be employed by the energy
harvester system at different times, or at the same time, and
operate without requiring any battery or source of external
power.
[0038] Referring now to the drawings, FIGS. 1A and 1B illustrate
exercise equipment 10, as exemplified by strength training
equipment, provided with an independent power generating energy
harvester system depicted as reference numeral 12 in FIG. 4A.
[0039] The strength training equipment 10 is shown as a weight
training machine having a seated portion 14 connected to an upright
support portion 16. The seated portion 14 includes a pair of
laterally extending arms 18 equipped with a pair of inner pulleys
20 and a pair of outer pulleys. The upright support portion 16
includes a resistance arrangement embodied in a weight stack 24
formed by a plurality of we plates which are arranged to move up
and down in various combination on guides as is well known in the
exercise equipment art. A belt or cable 26 is guided around the
outer pulleys 22, along the arms 18, around the inner pulleys 20
and down along the seated portion 14 into the upright support
portion 16.
[0040] The belt or cable 26 is then directed around an upper pulley
28 connected to a top end of an upright support portion 16, a lower
pulley 30 secured to the upper end of the weight stack 24, and a
pulley generator assembly 32 also joined to the top end of the
upright support portion 16. The pulley generator assembly 32 forms
part of the energy harvester system 12 and takes the lace of a
standard pulley which would normally be present in the weight
training machine 10. However, it would also be possible to dedicate
a pulley as an "energy harvester pulley," whereby the standard
pulleys would remain, and an energy harvester would be added. The
belt or cable 26 has outermost ends attached to a pair of gripping
handles 34 so that the selected weight plates in weight stack 24
may be moved up and down to provide variable resistance when a user
pulls and releases the handles 34. The pulleys 20, 22, weight stack
24, belt or cable 26, pulleys 28, 30, and handles 34 all cooperate
with the pulley generator assembly 32 to form a motion control
arrangement configured to move in response to stimulus in out a
user seated in the equipment 10. One skilled in the art should
appreciate that the motion control arrangement may otherwise be
formed by different linkages, and resistance components used in
combination with the pulley generator assembly 32.
[0041] The strength training equipment 10 includes a fitness
feedback system 36 for processing and providing information related
to the user of the equipment 10. The if feedback system 36 is
typically comprised of suitable electronics, such as LCD or LED
displays, sensors, data entry keyboard, touch screens,
microcontrollers, and wireless communication devices for providing
user identification, strength performance and workout summary data.
In the example shown in FIG. 1A, the fitness feedback system 36
includes an electronic display console 38 which is mounted to a
front face of the upright portion 16 of the strength training
equipment 10 so that it will be clearly visible and accessible to
the user positioned on the seated portion 14. The feedback system
36 could also be designed to provide and process information by
means of speech input and output.
[0042] In one embodiment of the present disclosure, the energy
harvester system 12 is incorporated in and responsive to motion of
the exercise equipment 10 as a result of a stimulus supplied by the
user. The energy harvester system 12 is generally comprised of a
kinetic energy harvester for converting kinetic energy provided due
to the motion of the equipment 10 into electrical energy, a
photovoltaic energy harvester for converting photovoltaic energy
provided by ambient light environment associated with the equipment
10 into electrical energy, and control electronics for controlling
the kinetic and photovoltaic energy harvesters to provide
electrical power to an electronics load of the fitness feedback
system 36 exclusive of any battery or external power source.
[0043] Referring to FIGS. 2A and 2B, the kinetic energy harvester
includes the pulley generator assembly 32 having an electricity
generator 40 and a belt and pulley system 42 which are mounted to a
frame 44 that is secured to the upright portion 16 of the exercise
equipment 10.
[0044] The electricity generator 40 is preferably a three phase
radial flux permanent magnet-type and consists of a round rotating
member or rotor 46 that is rotatably mounted on frame 44, and a
stationary member or stator 48 that is fixed to the frame 44 by a
mounting clamp 50. The rotor 46 consists of a plurality of
permanent magnets disposed on the outer circumference of the rotor
46 arranged such that the magnetic polarity of the magnets is
alternating. The stator 48 consists of a hollow core of
ferromagnetic material, comprising a circular inner diameter that
captures the magnetic flux from the rotor magnets, and a plurality
of electrically conducting coils 52 disposed in the slots of the
core. The inner diameter of the stator 48 is larger than the outer
diameter of the rotor 46. The rotor 46 s supported by a bearing 54
that allows the rotor 46 to rotate freely about an axis of
rotation, and limits the motion of the rotor 46 in the axial
direction so that the rotor 46 remains substantially centered
inside the stator 48 both radially and axially. An electrical
connection or wire 56 extends between the stator 48 and the control
electronics.
[0045] It is understood that other types of electricity generators
may be used and fall within the scope and spirit of this
disclosure. Other permanent magnet generator types include, but are
not limited to, interior permanent magnet synchronous generators,
rotors that employ flux focusing magnet arrays, and axial flux
generators using single or double sided stators. These alternative
permanent magnet generator topologies are applied in various
industries and would be obvious to those skilled in the art.
[0046] The belt or pulley system 42 includes a bi-directional low
speed belt pulley 58 with a first diameter, a bi-directional high
speed belt pulley 60 with a second diameter less than the diameter
of the low speed pulley 58, and a belt 62 that couples the rotation
of the pulleys 58, 60. The pulleys 58, 60 are rotatably mounted to
the frame 44. The high speed belt pulley 60 is coupled to the rotor
46 of the electricity generator 40, and generally shares the same
high speed bearing 54. The low speed belt pulley 58 is engaged with
belt or cable 26 (as seen in. FIGS. 2C and 2D), and is coupled to a
pulley such as 28 that rotates due to the motion of the exercise
equipment 10 and can generally share the same low speed bearing
system. The high speed pulley 60 rotates in proportion to the
motion of the low speed pulley 58 in either direction of rotation.
The ratio of the rotational speed of the high speed belt pulley 60,
.omega..sub.ES and the rotational speed of the low speed belt
pulley 58 .omega..sub.LS is defined as the motion ratio, MR. The
motion control ratio is determined by the diameters of the pulleys
58, 60, D.sub.LS and D.sub.HS, respectively, as defined in equation
2:
MR=.omega..sub.HS/.omega..sub.L3 (1)
MR=D.sub.LS/D.sub.HS (2)
where in deriving equations (1) and (2), it has been assumed that
the belt 62 does not slip on the pulleys 58, 60. The selection of
the motion ratio is a design parameter that can be optimized to the
specific strength training equipment 10. A primary goal of the
motion ratio of the pulley system is to minimize the size and the
cost of the electricity generator 40. For a desired level of power
generated, an electricity generator 40 that rotates at a higher
speed requires proportionally less torque than would be required if
the speed of the electricity generator rotation was equal to that
of the low speed pulley 58. The size of the electricity generator
40 is proportional to the torque (and not the power), thus it is
generally advantageous to define the speed of rotation of the high
speed pulley 60 to be much greater than the speed of the low speed
pulley 58.
[0047] There are limitations of the appropriate maximum value of
the motion ratio. A significant factor is that the inertia of the
energy harvester system 12, as reflected by the motion of the
strength training equipment 10, increases quadratically as the
motion ratio is increased. The inertia reflected by the motion of
the strength machine appears as an apparatus mass to the user of
the strength training equipment 10. For motion ratios that are too
high, the apparent mass will be perceived by the user and may
become objectionable. This effect is one factor that can be used to
determine the upper limit of the desired motion ratio.
[0048] A variety of configurations may be used to create a desired
motion ratio without departing from the scope and spirit of this
disclosure. Different belt types including, but not limited to,
V-belts, knurled belts, and tread belts may be used in
accomplishing the function of the belt and pulley system 42.
Furthermore, alternative methods of creating rotational motion
ratios are well known and include, but are not limited to, teeth
gears, friction gears, helical stages and planetary gears.
[0049] For example, the pulley generator assembly 32 can be
suitably replaced by a gear generator assembly 64 illustrated in
FIG. 2E. Instead of employing pulleys 58, 60, the gear generator
assembly 64 utilizes a set of gears, namely a gear wheel 66 having
a first diameter in meshing engagement with a pinion or gear wheel
68 having a second diameter less than the diameter of the gear
wheel 66. The gear wheels 66, 68 are rotatably mounted to the frame
44. The pinion 68 is coupled to the rotor 46 of the electricity
generator 40, and the gear wheel 68 is engaged with belt or cable
26.
[0050] Referring to FIG. 4A, the photovoltaic energy harvester
includes a photovoltaic array 70 that converts ambient light energy
from commercial lighting and/or sunlight in the equipment
environment into electrical energy, and a parallel electrical
energy storage element. 72, such as a capacitor 74, connected at
the output of the photovoltaic array 70. The array 70 generally
includes a plurality of photovoltaic cells, connected in series,
parallel or a combination thereof, to produce a desired output
power characteristic for the electronics load of the feedback
system 36 or to the control electronics. The output voltage of the
photovoltaic energy harvester operates at a load current that
results in a substantially constant voltage when connected to an
electronics load or standby electronics load.
[0051] The parallel electrical energy storage element 72 is able to
provide power to the electronics load or standby load when the
available output power from the photovoltaic array 70 is less than
the power required by the electronics load of the feedback system
36. When the power from the photovoltaic array 70 exceeds the power
required by the electronics load, the parallel electrical energy
storage element 72 can be charged resulting in an increase in
stored energy.
[0052] In an alternative embodiment shown in FIG. 4B, the
photovoltaic energy harvester comprises a photovoltaic array 76
that converts ambient light energy into electrical energy, and a
maximum power point tracker (MPPT) 78. The output of the
photovoltaic array 70 connects to the input of the maximum power
point tracker 73. The output voltage of the maximum power point
tracker 78 connects to the electronics load, or standby electronics
load and the parallel electrical energy storage element 72. In this
embodiment, the maximum power point tracker 78 is a DC/DC converter
that can be controlled in such a way that the maximum power is
harvested from the photovoltaic array 76 at any point in time. The
same DC/DC converter can also be used in a mode that is used to
control the amount of stored energy in the parallel electrical
energy storage element 72. Those who are skilled in the art will
recognize that there are a variety or well known maximum power
point control apparatus and techniques that can be applied to
maximize energy capture from the photovoltaic array 76. Those who
are skilled in the art will also recognize that there are a variety
of well known controlled apparatus and techniques that can be
applied to manage the amount of energy stored in the photovoltaic
energy storage element 66, and these techniques fall within a scope
and spirit of the present disclosure.
[0053] As seen in FIGS. 1A and 1E, the photovoltaic energy
harvester is a separate subassembly within the energy harvester
system 12. In this embodiment, the array 70 or 76 of the
photovoltaic energy harvester is located on a top end of the
support portion 16 of the strength training equipment 10 at a
location and in an orientation such that the ambient-radiated light
energy is substantially orthogonal to the photovoltaic cells that
comprise the photovoltaic array 70 or 76. The photovoltaic energy
harvester has mechanical features to allow the orientation of the
photovoltaic array 70 or 76 to be manually adjusted at the
installed location in the fitness facility. The mechanical features
allow the photovoltaic energy harvester to be rotated, tilted or
otherwise positioned at an orientation that can maximize the
capture of radiated light energy for a given location of the
fitness equipment on which the harvester is installed. Advantages
of this configuration include the ability to locate the
photovoltaic array 70 or 76 precisely to capture the maximum amount
of power from the ambient-radiated light and fitness
environment.
[0054] In an alternative embodiment shown in FIGS. 3A and 3B, the
photovoltaic energy harvester array 70 or 76 is integrated into the
fitness feedback display console 38 of the weight machine 10.
Advantages of this location are that the photovoltaic energy
harvester may be packaged cost effectively into a singe fitness
feedback display assembly. In this embodiment, the array 70 or 76
will be close to the standby electronics load to which it is
connected, and also the display console 38 will generally be easily
accessible for cleaning and occasional removal of any soil or
debris build up on the photovoltaic array 70 or 76.
[0055] A variety of photovoltaic array technologies may be used
without departing from the scope and spirit of this disclosure.
Examples of photovoltaic technologies include, but are not limited
to, polycrystalline and monocrystiline silicone and variants
thereof, and thin film technology such as amorphous silicone,
cadmium telluride, CIGS, etc.
[0056] With further reference to FIG. 4A, the control electronics
generally includes a three phase power inverter 80, a DC/DC
converter 82, a combiner circuit 84 and a harvester controller 86
that controls components 80, 82 and 84. The AC terminals of the
three phase power inverter 80 are connected to the three phase AC
electricity generator 40 and can be considered the input terminals
of the inverter 80. The DC terminals of the three phase power
inverter 80 can be considered as the output terminals, and are
connected to a DC link, which consists of an electrical energy
storage element 88, such as a capacitor 90. The purpose of the
three phase power inverter 80 is to convert the variable voltage
amplitude, variable frequency AC input power to a DC output power
that has a non-zero, non-negative average value of voltage. For
proper operation of the energy harvester system 12, the DC output
voltage of the inverter 80 can be controlled to be constant, but
more generally may be varying as long as the condition of the
non-zero, non-negative average voltage are met.
[0057] Furthermore, the purpose of the three phase power inverter
80 is to control the electricity generator 40 to operate
efficiently, and therefore produce desired electrical output power
without requiring excessive mechanical power to be derived from the
low speed pulley 58. The three phase inverter 80 consists of
efficient power switching devices, such as MOSFETs, that are
capable of being controlled by the harvester controller 86. The
three phase inverter 80 may also consist only of diodes to operate
a standard rectifier. Those who are skilled in the art will
recognize that there are a variety of well known generator and
inverter control techniques that can be applied to optimize the
efficiency and/or the energy capture from the electrical generator
40 as well as the overall efficiency and/or energy capture of the
energy harvester system 12.
[0058] The DC/DC converter 82 provides a constant regulated output
voltage, i.e. the DC supply voltage, for use by the electronics
load of the feedback system 36. The input of the DC/DC converter 82
is connected to the DC link, the DC link generally operating at a
higher voltage than the DC supply voltage and consisting of the
capacitor 90 connected in parallel with the input of the DC/DC
converter 82 and the output of the three phase inverter 80. The
DC/DC converter 82 is capable of providing constant DC supply
voltage even in the presence of varying DC link voltage caused by
fluctuations of the power output of the three phase inverter 80 as
depicted a FIG. 5B. The DC/DC converter 82 need only provide
unidirectional power flow from the DC link 88 to the electronics
load of the feedback system 36. The DC/DC converter 82 will
generally operate as a buck converter, but may also operate as a
boost converter if the DC link voltage is operating at a voltage
that is less than the DC supply voltage. Those who are skilled in
the art will recognize that there are a variety of well known
unidirectional DC/DC converter types that can be used to
effectively and efficiently convert, a first generally varying DC
input voltage to a second constant DC output voltage level.
[0059] The combiner circuit 84 is used to apply the best available
power source to the electronics load of the fitness feedback system
36. In one embodiment, the combiner circuit 84 consists of two
diodes with a first diode anode connected to the output of the
kinetic energy harvester and a second diode anode connected to the
output of the photovoltaic energy harvester. The cathodes of each
diode are connected together at the combiner circuit output voltage
node. If power is available from the kinetic energy harvester, the
combiner circuit 84 will transfer kinetic power to the electronics
load in a kinetic harvesting mode. If power is not available from
the kinetic energy harvester, the combiner circuit 84 will apply
only the power available from the photovoltaic energy harvester in
a photovoltaic or standby harvesting mode. Those who are skilled in
the art will recognize that there are a variety of well known
techniques for combining the power output of two time varying DC
voltages, not limited to the technique described above.
[0060] In an alternative embodiment, a combiner circuit 84 is not
used. Instead, the output of the kinetic energy harvester is
directly connected to the electronics comprised off fitness
feedback system 36 so that the control electronics 80, 82, 86,
control only the electrical power from the kinetic energy
harvester. The output of the photovoltaic energy harvester is
connected to provide power only to the electronics that comprise
the user identification portion of the feedback system 36, and/or
other circuitry that may rewire power while energy not available
from the kinetic energy harvester.
[0061] The control electronics regulate the instantaneous power
that is developed by the kinetic energy harvester in the kinetic
harvesting mode. During the use of strength exercise equipment 10,
the input motion of the user can generally be considered as
creating reciprocating motions. Therefore, during a single
repetition or a series of repetitions there will be periods of slow
motion, periods of fast motion, as well as brief periods of zero
motion. When the exercise motion is slow (i.e. low velocity) the
control electronics will harvest an amount of power that is less
than the average output power from the kinetic energy harvester.
When the exercise motion is fast, the control electronics will
harvest an amount of power that is greater than the average output
power from the kinetic energy harvester. During the brief periods
of zero motion that are typical, for example, between the
repetitions that comprise a set of exercise, the control
electronics will harvest zero power from the exercise equipment
10.
[0062] Therefore, it can be observed that the operation of the
kinetic energy harvester is such that the instantaneous power that
is harvested from the exercises is generally not equal to (either
more or less than) the output power supplied by the DC supply
voltage of the kinetic energy harvester.
[0063] To observe the difference in instantaneous power at the
output of the electricity generator 40 and the output power of the
kinetic energy harvester (i.e. the DC supply voltage), the control
electronics also includes the passive, electrical energy storage
element 88, such as the parallel connected capacitor 90. When a
total exercise motion is at or near a point of zero motion, the
output power of the kinetic energy harvester will be substantially
supplied by the electrical energy storage element 88, and therefore
the electrical energy storage element 88 will be partially
discharged. When a total exercise motion is at or near a point of
fast motion, the electrical energy storage element 88 will be
discharged as required, and the output power of the kinetic energy
harvester will be substantially supplied by the electricity
generator 40.
[0064] It should be reiterated that one intent of the present
disclosure is to eliminate the need for any long term energy
storage elements, such as rechargeable or non-rechargeable
electrochemical batteries, as well as the need for any external
power, so that the energy harvester system 12 is completely
self-sufficient.
[0065] A variety of passive energy storage elements may be used
without departing from the scope and spirit of this disclosure. For
example, different types of capacitors including electrolytic,
film, ultra capacitors and super capacitors can be used, as well as
methods of inductive energy storage.
[0066] In one embodiment of the present disclosure, when a
condition of very little motion or no motion persists, the control
electronics detects this condition, and switches to the
photovoltaic energy harvester or the standby harvesting mode where
the average power of the electronics load is harvested from the
photovoltaic array 70 or 76. The transition to the standby
harvesting mode generally does not occur until the energy stored in
the energy storage element 88 has been substantially discharged sum
that it can no longer supply power to the electronics load of the
fitness feedback system 36. The photovoltaic energy harvester
converts power in the form of radiated light in the ambient
environment, for example, the commercial lighting typically used in
fitness facilities into DC electrical power. The photovoltaic
energy harvester can also convert radiated, naturally appearing
sunlight that may be present in the exercise equipment environment
into DC electrical power.
[0067] In one embodiment of the present disclosure, the output
power from the photovoltaic array 70, 76 can be used directly (i.e.
without the need for active electronics to control power from the
array) as the output DC supply voltage. The photovoltaic energy
harvester may be configured such that the electrical power created
by the photovoltaic array 70, 76 is available as a separate DC
supply voltage, or connected to the same output DC supply voltage
terminals used during the kinetic harvesting mode.
[0068] Thus, it should be appreciated that in the kinetic
harvesting mode, the energy harvester system 12 produces a steady
output voltage and output power in the presence of reciprocating
user input motion that is caused by the use of strength training
equipment 10. Furthermore, when no input motion is present, the
energy harvester system 12 is able to provide a reduced amount of
power for the purposes of powering standby functions (the standby
harvesting mode). An example of a powered standby function is a
user identification system, via console 38, such as passive or
active RFID system, capacitive or resistive touch screen systems,
and other forms of contact and non-contact user identification
systems. In the standby harvesting mode, the average power required
by the electronics load is supplied by the photovoltaic array 70 or
76 of the energy harvester system 12.
[0069] It should be further understood that the control electronics
is able to control the current in the electricity generator 40.
When motion is present, the electricity generator 40 produces an AC
output voltage amplitude that is proportional to the velocity of
the exercise motion. The control electronics controls the n current
in the generator coils 52 so that the mechanical power available
during the motion of the strength equipment 10 is converted to
electrical power at the electrical terminals of the electrical
generator 40. The control electronics converts the AC output
voltage from the generator 40 into an average, positive DC link
output voltage. The DC link output voltage may be controlled to be
constant or varying, and in the varying case, the voltage will
always have a positive value and therefore retain an average DC
value. This DC link output voltage is generally not suitable for
use by the exercise equipment electronics or a fitness feedback
system 36. However, the DC/DC converter 82 of the control
electronics also converts the variable DC link voltage into a
constant DC supply voltage, typically 3.3 Vdc, 5 Vdc, or 12 Vdc (or
any value that is less than the DC link operating voltage). The
constant DC supply voltage is the output DC voltage that is
suitable for use by the exercise equipment electronics such as the
electronics, for the fitness feedback system 46.
[0070] As represented in FIG. 3A, the electrical power supplied
from the kinetic voltage energy harvesters is used to
independently, without any battery or external electricity, power
the display console 38 of the feedback system 36 to identify, for
example, via a display screen resistance being used, the number of
sets and repetitions expended, and the amount of rest between the
sets of exercise. Other data may be provided to or input for
processing by the user.
[0071] During typical operation of strength training equipment 10,
the weight stack 24 and related pulleys 28, 30 are exposed to a
typical range of linear and rotational velocities, respectively.
For a given machine (e.g. a lateral pull down machine), this range
of velocities depends on factors such as the exercise in of the
person using the equipment 10. The kinetic energy harvester is
designed to reliably provide power to the fitness feedback system
36 over this typical velocity range, which corresponds to a range
of different user styles and user workout intents. Though
infrequent, under certain circumstances, the typical range of
velocities can be exceeded substantially, which can be considered
to be a high velocity condition. A high velocity condition may
occur because of misuse, or in the event of an overly aggressive
exercise movement, by the user.
[0072] Without a provision to handle a high velocity condition,
damage to the circuits and components (e.g. the AC to DC inverter
80) that comprise kinetic energy harvester can occur. In order to
prevent damage during these conditions, an overvoltage protection
arrangement, as depicted in FIG. 4C, is included in the kinetic
energy harvester.
[0073] The overvoltage protection arrangement provides a means of
reliably limiting voltage (AC voltage or DC link voltage, or both)
during a high velocity condition. In one embodiment of the present
disclosure, the overvoltage protection arrangement can be
accomplished by means of a voltage clamp apparatus 94 disposed
across the DC link 88 (i.e. a parallel connection). The clamp
network consists of a fast switch with DC blocking capability, a
surge-rated power resistor, and a means of controlling the switch
to connect the resistor across the DC link 88 in response to a high
velocity condition. When switched in, the resistor dissipates
energy from the electricity generator 40 that would otherwise act
to rapidly charge the DC link 88 capacitor and produce a damaging
overvoltage condition. In an alternative embodiment, an AC switch
96 in is disposed between the AC terminals of the electricity
generator 40 and the AC terminals of the AC to DC inverter 80 (i.e.
connected in series). The switch 96 is opened in response to a high
velocity condition in order to prevent excessive voltage build up
in the DC link 88. To those skilled in the art, it should be
obvious that there are a variety of overvoltage protection methods,
arrangements and topologies that may be applied while still falling
within the scope and sod sit of this invention. These arrangement
include, but are not limited to series or parallel connections of
switches, resistors, and overvoltage protection devices (such as
TVS clamp diodes, MOV, or zener diodes) located in the DC link 88
or located between the AC terminals of the electricity generator 40
and the AC terminals of the AC to DC inverter 80.
[0074] Although the energy harvester system 12 has been described
in use with the strength training equipment 10, it should be
understood that the energy harvester system 12 can also be adapted
to other exercise equipment having motion control components.
[0075] Various alternatives are contemplated as being within the
scope of the following claims particularly pointing out and
distinctly claiming the subject matter regarded as the
invention.
[0076] The foregoing is considered as illustrative only of the
principles of the invention. Furthermore, since numerous
modifications and changes will readily occur to those skilled in
the art, it is not desired to limit the invention to the exact
construction and operation shown and described. While the preferred
embodiment has been described, the details may be changed without
departing from the invention, which is defined by the claims.
* * * * *