U.S. patent application number 14/438269 was filed with the patent office on 2015-11-26 for mechanical devices and method of creating prescribed vibration.
The applicant listed for this patent is LORD CORPORATION. Invention is credited to Russell E. ALTIERI, Askari BADRE-ALAM, Eric CADY, Brian CARR, Ben HOLTON, Anthony HUNTER, Mark R. JOLLY, Bradley N. JONES, Jonathan M. OWENS.
Application Number | 20150340981 14/438269 |
Document ID | / |
Family ID | 49515575 |
Filed Date | 2015-11-26 |
United States Patent
Application |
20150340981 |
Kind Code |
A1 |
JOLLY; Mark R. ; et
al. |
November 26, 2015 |
MECHANICAL DEVICES AND METHOD OF CREATING PRESCRIBED VIBRATION
Abstract
The invention provides a system for creating a prescribed
vibration profile on a mechanical device comprising a sensor (30)
for measuring an operating condition of the mechanical device, a
circular force generator CFG (20) for creating a controllable
rotating force vector comprising a controllable force magnitude, a
controllable force phase and a controllable force frequency, a
controller (22) in electronic communication with said sensor and
said circular force generator, the controller operably controlling
the controllable rotating force vector, wherein the difference
between the measured operating condition and a desired operating
condition is minimized.
Inventors: |
JOLLY; Mark R.; (Raleigh,
NC) ; ALTIERI; Russell E.; (Holly Springs, NC)
; BADRE-ALAM; Askari; (Cary, NC) ; OWENS; Jonathan
M.; (Chapel Hill, NC) ; HUNTER; Anthony;
(Cary, NC) ; JONES; Bradley N.; (Crestview Hills,
KY) ; CARR; Brian; (Florence, KY) ; HOLTON;
Ben; (Cincinnati, OH) ; CADY; Eric; (Florence,
KY) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LORD CORPORATION |
Cary |
NC |
US |
|
|
Family ID: |
49515575 |
Appl. No.: |
14/438269 |
Filed: |
October 23, 2013 |
PCT Filed: |
October 23, 2013 |
PCT NO: |
PCT/US2013/066500 |
371 Date: |
April 24, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61719084 |
Oct 26, 2012 |
|
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|
Current U.S.
Class: |
318/114 |
Current CPC
Class: |
B06B 1/161 20130101;
H02P 25/032 20160201 |
International
Class: |
H02P 25/02 20060101
H02P025/02 |
Claims
1. A system for creating a prescribed operating function within a
mechanical device comprising: a mechanical device; at least one
circular force generator (CFG) affixed to the mechanical device,
the CFG capable of producing a rotating force vector, wherein the
rotating force vector includes a magnitude, a phase, and a
frequency; at least one prescribed vibration profile created in the
mechanical device by the CFG; at least one sensor positioned on the
mechanical device; an operating function measured by the sensor and
associated with and enabled by the vibration profile; a controller
in electronic communication with the sensor and with the CFG, the
controller operably controlling the rotating force vector based
upon the measurement of the operating function, wherein the
magnitude, phase and frequency are independently controllable by
the controller, wherein the controller changes the rotating force
vector; and, wherein a difference between the measured operating
function and the prescribed operating function is reduced.
2. The system of claim 1, wherein the CFG further comprises two
imbalanced rotors independently rotated by two motors.
3. The system of claim 1, further comprising a second CFG, the
second CFG operating at the same frequency as the CFG.
4. The system of claim 3, wherein one of the CFGs produces the
force vector in a clockwise direction and the other CFG produces
the force vector in a counter clockwise direction, wherein the
combination of the two force vectors produce a resultant force
vector that is controllable in two degree-of-freedom, the resultant
force vector inducing a vibratory motion in the mechanical device
and creating the prescribed operating function.
5. The system of claim 1, wherein the prescribed operating function
is a prescribed vibration profile and the sensor detects an
operating vibration profile and captures a measurement thereof.
6. The system of claim 1, wherein the vibratory profile is an
elliptical vibratory motion at one specific frequency.
7. The system of claim 1, wherein the vibratory profile is selected
from the group consisting of linear, elliptical and orbital
motions.
8. The system of claim 2, wherein the two motors are brushless
permanent magnet motors.
9. The system of claim 1 wherein the sensor is an
accelerometer.
10. The system of claim 1 wherein the sensor is a plurality of
accelerometers.
11. The system of claim 9 wherein said accelerometers are colocated
with said CFG.
12. The system of claim 1, wherein the sensor is selected from the
group consisting of accelerometers, thermocouples, infrared
sensors, particle matter sensors, mass flow rate sensors, load
sensors, optical sensors and combinations thereof.
13. The system of claim 12 wherein the sensor is a plurality of
sensors.
14. A system for creating a prescribed vibration profile within a
mechanical device comprising: a mechanical device; at least one
circular force generator (CFG) affixed to the mechanical device,
the CFG capable of producing a rotating force vector, wherein the
rotating force vector includes a magnitude, a phase, and a
frequency; at least one sensor positioned on the mechanical device;
a controller in electronic communication with the sensor and with
the CFG, the controller operably controlling the rotating force
vector based upon the measurement of the vibration profile, wherein
the magnitude, phase and frequency are independently controllable
by the controller, wherein the controller changes the rotating
force vector; at least one vibration profile in the mechanical
device created by the CFG, wherein the sensor measures a measured
vibration profile; wherein a difference between the measured
vibration profile and a prescribed vibration profile is
reduced.
15. The system of claim 14, wherein the CFG further comprises two
imbalanced rotors independently rotated by two motors.
16. The system of claim 14, further comprising a second CFG, the
second CFG operating at the same frequency as the CFG.
17. The system of claim 16, wherein one of the CFGs produces the
rotating force vector in a clockwise direction and the other CFG
produces the rotating force vector in a counter clockwise
direction, wherein the combination of the two rotating force
vectors produce a resultant force vector that is controllable in
two degree-of-freedom, the resultant force vector inducing a
vibratory motion in the mechanical device and creating the
prescribed vibration profile.
18. The system of claim 17, wherein the prescribed vibratory motion
is an elliptical vibratory motion at one specific frequency.
19. The system of claim 14, wherein the prescribed vibration
profile is selected from the group consisting of linear, elliptical
and orbital motions.
20. The system of claim 15, wherein the two motors are brushless
permanent magnet motors.
21. The system of claim 14 wherein the sensor is an
accelerometer.
22. The system of claim 14 wherein the sensor is a plurality of
accelerometers.
23. The system of claim 22 wherein said accelerometers are
colocated with said CFG.
24. A method for creating a prescribed operating function on a
mechanical device having at least one CFG capable of producing a
rotating force vector with a controllable magnitude, phase and
frequency, a sensor and a controller, and the CFG capable of
creating at least one vibration profile in the mechanical device
the method comprising the steps of: defining a prescribed operating
function; measuring the operating function operation with the
sensor and generating a measured operating function; communicating
the measured operating function from the sensor to the controller;
calculating an error by comparing the measured operating function
to the prescribed operating function; processing the error in the
controller using an algorithm, wherein the processing produces a
command for the CFG, the command for including changes to the
magnitude, the phase, and/or the frequency of the rotating force
vector; and communicating the changes to the force vector to the
CFG such that the difference between the measured operating
function and the prescribed operating function is reduced.
25. A method of claim 24, further comprising the step of using a
feedback control algorithm.
26. A method of claim 24, further comprising the step of using an
open-loop adaptive algorithm.
27. A method of claim 24, further comprising the step of using a
non-adaptive open-loop algorithm.
28. A method of claim 24, further comprising the step of using a
filtered-x least mean square (Fx-LMS) gradient descent
algorithm.
29. A method of claim 24, further comprising the step of using
time-average gradient (TAG) algorithm.
30. A method of claim 24, wherein the measuring step further
comprises using a sensor selected from the group consisting of
accelerometers, thermocouples, infrared sensors, particle matter
sensors, mass flow rate sensors, load sensors, optical sensors, and
combinations thereof.
31. A method of claim 30, wherein the measuring step further
comprises using a plurality of sensors.
32. A method of claim 31, wherein the measuring step further
comprises using a plurality of different sensors.
33. The system of claim 1, wherein the mechanical device is
selected from the group consisting of a vibratory deliquifying
machine, a vibratory conveyor, a vibratory feeder, a vibratory
shaker, a vibratory separator, a material separator, an attrition
mill, a mold shakeout machine, a vibratory compactor, and a seismic
impulse exciter.
34. The system of claim 1, where the mechanical device is selected
from the group consisting of an aircraft engine, a rotary wing
aircraft hub, a propeller hub, and a landing craft fan hub.
35. The system of claim 1, wherein the mechanical device is
selected from the group consisting of a building, a bridge, a
medical device, and a medical bed.
36. The system of claim 14, wherein the mechanical device is
selected from the group consisting of a vibratory deliquifying
machine, a vibratory conveyor, a vibratory feeder, a vibratory
shaker, a vibratory separator, a material separator, an attrition
mill, a mold shakeout machine, a vibratory compactor, and a seismic
impulse exciter.
37. The system of claim 14, where the mechanical device is selected
from the group consisting of an aircraft engine, a rotary wing
aircraft hub, a propeller hub, and a landing craft fan hub.
38. The system of claim 14, wherein the mechanical device is
selected from the group consisting of a building, a bridge, a
medical device, and a medical bed.
39. The system of claim 24, wherein the mechanical device is
selected from the group consisting of a vibratory deliquifying
machine, a vibratory conveyor, a vibratory feeder, a vibratory
shaker, a vibratory separator, a material separator, an attrition
mill, a mold shakeout machine, a vibratory compactor, and a seismic
impulse exciter.
40. The system of claim 24, where the mechanical device is selected
from the group consisting of an aircraft engine, a rotary wing
aircraft hub, a propeller hub, and a landing craft fan hub.
41. The system of claim 24, wherein the mechanical device is
selected from the group consisting of a building, a bridge, a
medical device, and a medical bed.
Description
[0001] Some mechanical devices perform specific functions through
use of induced vibratory motion. Such devices include monitoring
damage detection and structural assessment of civil structures and
mechanical devices, damping in civil structures, searching for oil
and gas with seismic impulse exciters, medical device and
equipment, controlling fluid flow in a pipe, deliquifying screens,
material separators, vibratory feeders and conveyors, attrition
mills, mold shakeout machines, and vibratory compactors. Typically
these devices utilize one or more force generators to create a
predefined force profile for inducing vibration within the device.
These force generators may include linear drives or imbalanced
rotors driven by synchronous motors or induction motors whose speed
is an integer fraction of the electrical source frequency. To vary
the frequency of vibration, variable frequency drives (VFDs) are
used in conjunction with these motors. To tailor the shape of the
vibration profile or create a resonance for the purpose of
amplifying the vibration response, springs, stabilizers, and/or
mechanical pivots are used. When multiple synchronous or
asynchronous motors are used on the same device and are coupled
through common base vibration, they tend to synchronize with each
other to produce a consistent and predesigned force profile.
[0002] The aforementioned devices are incapable of maintaining a
desired vibration profile when operating conditions change, such as
a change in material loading, changes in temperature, changes in
material properties, or other variables that can alter the response
of the mechanical device. In some cases, the aforementioned devices
cannot create certain desirable vibration profiles. In other cases,
the aforementioned devices cannot create a variety of selectable
vibration profiles within limits imposed by the authority of their
respective force generators.
SUMMARY OF THE INVENTION
[0003] In accordance with the present invention a system for
creating a prescribed operating function within a mechanical
device. The system comprises a mechanical device, at least one
circular force generator (CFG), at least one sensor and a
controller. The CFG is affixed to the mechanical device. The CFG is
capable of producing a rotating force vector, wherein the rotating
force vector includes a magnitude, a phase, and a frequency,
wherein the CFG creates at least one vibration profile in the
mechanical device. The at least one sensor is positioned on the
mechanical device, wherein the sensor measures an operating
function associated with and enabled by the vibration profile. The
controller is in electronic communication with the sensor and with
the CFG, the controller operably controlling the force vector based
upon the measurement of the operating function, wherein the
magnitude, phase and frequency are independently controllable by
the controller, wherein the controller changes the force vector.
Wherein a difference between the measured operating function and a
prescribed operating function is reduced.
[0004] In accordance with the present invention a system for
creating a prescribed vibration profile within a mechanical device.
The system comprises a mechanical device, at least one circular
force generator (CFG), at least one sensor and a controller. The
CFG is affixed to the mechanical device. The CFG is capable of
producing a rotating force vector, wherein the rotating force
vector includes a magnitude, a phase, and a frequency, wherein the
CFG creates at least one vibration profile in the mechanical
device. The at least one sensor is positioned on the mechanical
device, wherein the sensor measures a vibration profile associated
with and enabled by the vibration profile. The controller is in
electronic communication with the sensor and with the CFG, the
controller operably controlling the force vector based upon the
measurement of the vibration profile, wherein the magnitude, phase
and frequency are independently controllable by the controller,
wherein the controller changes the force vector. Wherein a
difference between the measured vibration profile and a prescribed
vibration profile is reduced.
[0005] In another aspect, the invention provides for a method for
creating a prescribed operating function on a mechanical device
having at least one CFG capable of producing a rotating force
vector with a controllable magnitude, phase and frequency, a sensor
and a controller, and the CFG is capable of creating at least one
vibration profile in the mechanical device, the method comprising
the steps of: [0006] (a) defining a prescribed operating function;
[0007] (b) measuring an operating function with the sensor; [0008]
(c) communicating the measured operating function from the sensor
to the controller; [0009] (d) calculating an error by comparing the
measured operating function to the desired operating function;
[0010] (e) processing the error in the controller using an
algorithm, wherein the processing produces a command for the CFG,
the command including changes to the magnitude, the phase, and/or
the frequency of the rotating force vector; [0011] (f)
communicating the changes to the force vector to the CFG such that
the difference between the measured operating function and the
prescribed operating function is reduced.
[0012] Numerous objects and advantages of the invention will become
apparent as the following detailed description of the preferred
embodiments is read in conjunction with the drawings, which
illustrate such embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 illustrates a perspective view of a deliquifying
screen with circular force generators positioned thereon.
[0014] FIG. 2 illustrates a typical vibration prescribed vibration
profile enabled by the present invention.
[0015] FIG. 3 illustrates a perspective view of a vibratory
conveyor with circular force generators positioned thereon.
[0016] FIG. 4 illustrates a perspective view of a vibratory
material separator with circular force generators positioned
thereon.
[0017] FIG. 5A illustrates one embodiment of a Circular Force
Generator (CFG).
[0018] FIG. 5B illustrates a partial cut-away view of the CFG of
FIG. 5A.
[0019] FIG. 6 illustrates another embodiment of a CFG. In this case
the CFG comprises two separate identical components, one of which
is shown.
[0020] FIG. 7 illustrates yet another embodiment of a CFG. In this
case the CFG comprises two separate identical components, one of
which is shown.
[0021] FIGS. 8A-C illustrate force generation using two co-rotating
imbalanced rotors to create a circular force with controllable
magnitude and phase, thereby providing a CFG.
[0022] FIG. 9 illustrates two CFGs coaxial mounted on both sides of
a mounting plate.
[0023] FIG. 10 illustrates two CFGs mounted side-by-side on a
mounting plate.
DETAILED DESCRIPTION
[0024] The invention described herein is applicable to a wide range
of devices where a mechanically induced vibration is desired, the
non-limiting examples of vibratory deliquifying machines,
conveyors, and separators are used for illustration purposes.
[0025] Referring to the drawings, FIG. 1 shows the invention as
applied to the non-limiting example of a vibratory deliquifying
machine illustrated and generally designated by the numeral 10. The
non-limiting example vibratory deliquifying machine 10, as
illustrated, includes inlet 12, screen 14, exit 16, springs 18, and
force generators 20. Force generators 20 are preferably CFG 20.
[0026] In vibratory deliquifying machine 10, slurries (not shown)
enter inlet 12 where a vibratory motion causes the slurry to convey
across screen 14 suspended on springs 18. As the slurry is conveyed
across screen 14, liquid passes through screen 14 while dry
material (not shown) is extracted at exit 16.
[0027] Existing vibratory deliquifying machines 10 have a specific
elliptical vibratory motion at one specific frequency providing for
optimal performance. CFG 20, including controller 22, enables the
use of a prescribed elliptical vibratory motion for optimal
performance. In the case of the non-limiting example of vibratory
deliquifying machine 10, the prescribed elliptical vibratory motion
from CFGs 20 increases the separation of liquid and solid matter.
This also enables the maintenance of the optimal vibratory motion
even when the mass of the slurry or the center-of-gravity of the
slurry on screen 14 changes with time or operating condition.
[0028] In FIG. 1 two, CFGs 20 are mounted to screen structure 24 of
vibratory deliquifying machine 10. Referring to FIGS. 8A-8C for CFG
20, each CFG 20 is capable of creating rotating force vector 26
having a controllable magnitude F.sub.0, a controllable phase
.phi., and a controllable frequency .omega.. Two CFGs 20 operating
at the same frequency .omega. and proximal to each other, as shown
in FIGS. 1 and 8A-8C, where one is producing a clockwise rotating
force vector and one is producing a counter clockwise rotating
force vector, produce a resultant that is a controllable two
degree-of-freedom planar force. These applied forces act on screen
structure 24 and produce an induced vibratory motion.
[0029] In the non-limiting example illustrated in FIG. 1, CFGs 20
are mounted on centerline 28 of vibratory deliquifying machine 10.
This placement avoids creating a side-to-side rocking motion from
applied forces. Screen structure 24 is assumed to be a rigid body,
whereby the two proximal CFGs 20 create two degrees-of-freedom of
controllable planar motion. The addition of more CFGs 20 will
increase the degrees-of-freedom of controllable motion. For
example, the application of a third CFG 20 will allow for three
degrees-of-freedom of controllable planar motion. The maximum of
six CFGs 20 will allow for a full six degrees-of-freedom rigid body
control of motion. Depending upon the need, two-to-six CFGs 20 are
utilized on a rigid body to create controllable motion from two to
six two degrees-of-freedom, respectively.
[0030] In the non-limiting example of vibratory deliquifying
machine 10 illustrated in FIG. 1, sensors 30 are used to provide
input to controller 22. Sensors 30 are applied to the screen
structure 24. The location of sensors 30 is determined by the
particular data element being sensed. Sensors 30 monitor an aspect
of vibratory deliquifying machine 10 performance related to the
induced vibratory motion.
[0031] The signals from sensors 30 are received by controller 22.
Controller 22 commands the force magnitude, phase, and frequency of
each CFG 20. Within controller 22 resides at least one algorithm
comparing performance, as measured by sensors 30, with a desired
performance to produce an error. The algorithm then produces CFG
commands that that will reduce or minimize this error. Many methods
are known to those skilled in the art for reducing an error based
on sensor 30 feedback, including various feedback control
algorithms, open-loop adaptive algorithms, and non-adaptive
open-loop methods. In one exemplary embodiment, controller 22 uses
a filtered-x least mean square (Fx-LMS) gradient descent algorithm
to reduce the error. In another exemplary embodiment, the
controller uses a time-average gradient (TAG) algorithm to reduce
the error.
[0032] Sensors include all types of vibration sensors, including
digital, analog, and optical. Sensors also include accelerometers,
thermocouples, infrared sensors, mass flow rate sensors, particle
matter sensors, load sensors and optical sensors. The sensors may
be selected from the group consisting of vibration sensors,
accelerometers, thermocouples, infrared sensors, mass flow rate
sensors, particle matter sensors, load sensors, optical sensors and
combinations thereof. A plurality of sensors of the same type or a
plurality of different types sensors are employed to maximize the
measurement of the operating condition.
[0033] The mechanical devices contemplated herein perform specific
operating functions through use of induced vibratory profiles.
Operating functions material flow or movement, material separation,
material compaction, drying, pumping, as well as others. All of the
operating functions are enabled by the induced vibratory profile
and react to vibratory input from CFGs 20.
[0034] In an exemplary embodiment, sensors 30 are accelerometers
directly measuring the operating function of screen structure 24.
In this non-limiting embodiment, the operating condition measured
is the vibration profile of screen structure 24. Within controller
22 the measured operating function is compared with a desired or
prescribed vibration profile to produce an error. Controller 22
then implements an algorithm that produces CFG commands such that
the measured operating function moves toward the prescribed
vibration profile reducing the error. By way of illustration, FIG.
2 shows both a prescribed vibration profile (labeled as "Command")
and a measured vibration profile as measured by a biaxial
accelerometer located near the center-of-gravity of the screen
assembly. In FIG. 2 the prescribed vibration profile is illustrated
as a solid line and labeled as "Command," and the measured
vibration profile is illustrated as a dotted line and labeled as
"Measured." It can be seen that the difference, or error, between
these profiles is small.
[0035] In another illustrative non-limiting example, FIG. 3 shows
the present invention applied to vibratory feeder 100. Material is
fed onto feeder bed 102 of vibratory feeder 100 from hopper 104.
Vibratory motion conveys the material along feeder bed 102 where it
is then metered into another machine, or a package, or any one of a
number of secondary systems.
[0036] Application of the present invention enables a prescribed
elliptical vibratory motion for optimal performance of vibratory
feeder 100. Optimal performance includes precision metering of
material flow or high material conveyance rate without damaging or
dispersing the material. The present invention also enables the
maintenance of the optimal vibratory motion even when the mass of
the material on feeder bed 102 or the center-of-gravity of the
material on feeder bed 102 changes with time or operating
condition. In other embodiments or other uses the prescribed
vibration is selected from the group consisting of linear,
elliptical and orbital, as determined by the desired outcome.
[0037] Vibratory feeder 100 illustrated in FIG. 3 is used similarly
to the application to vibratory deliquifying machine 10 described
hereinabove and illustrated in FIGS. 1 and 2. Feedback sensors 106
shown are accelerometers, but may be sensors 106 that directly or
indirectly measure material flow rate. By way of non-limiting
example, sensors 106 shown in FIG. 3 are embedded within CFG 20
thereby eliminating extra connectors and wiring harnesses
associated therewith.
[0038] Referring to FIG. 4 vibratory material separator 200 is
illustrated as another non-limiting example. Vibratory material
separator 200, as illustrated, uses screens (not shown) and induced
vibratory motion to separate granular materials or aggregates based
on grain size and/or density. Using prescribed vibratory motion
generated by CFGs 20, the performance of material separators is
optimized. Optimal performance includes improving separation, or
improving throughput, or a combination thereof. Optimal performance
also includes enhancement of the screen life and anti-fouling of
the screen. The optimal vibratory motion is maintained even when
the mass of the material or the center-of-gravity of the material
within vibratory material separator 200 changes with time or
operating condition. The application of the present invention to
vibratory material separator 200 illustrated in FIG. 4 is very
similar to the application to previous examples described
hereinbefore.
[0039] FIGS. 5A-8C provide non-limiting examples of CFG 20 in
different variations. Referring to FIGS. 5A-6, CFG 20 consists of
two imbalanced masses 32a, 32b each attached to a shaft 34 and each
suspended between two rolling element bearings 36a, 36b. Each
imbalance mass 32a, 32b is driven by motor 38a, 38b. In exemplary
embodiments, the two motors 38a, 38b within CFG 20 are brushless
permanent magnet motors, sometimes called servo motors. Each motor
38a, 38b includes a sensor 40 for sensing the rotary position of
imbalanced masses 32a, 32b. Within the aforementioned controller
22, an algorithm employing Equation (1) that receives the rotary
position sensor feedback, and uses common servo motor control
techniques controls the rotary position 8 of each motor. The
equation employed is illustrated by Equation (1):
.theta.(t)=.phi.t+.omega. (Equation (1)
where .omega. is the rotational speed and .phi. is the rotational
phase. Rotational phase .phi. corresponds to the phase of the motor
(and thus the imbalanced mass) with respect to an internal
reference tachometer signal. Both imbalanced masses 32a, 32b
co-rotate at nominally the same speed .omega., and each imbalanced
mass 32a, 32b creates a centrifugal force whose magnitude is
mathematically determined by using Equation (2):
|F|=mr .omega..sup.2 Equation (2)
where mr is the magnitude of imbalanced mass 32a, 32b which is
typically expressed in units of Kg-m. The phase of the first
imbalanced mass 32a with respect to the second imbalanced mass 32b
(i.e., the relative phase) within CFG 20 will determine the
magnitude of resultant rotating force vector 26.
[0040] Referring to FIGS. 8A-C, a zero-force case and a full-force
case of imbalance masses 32a and 32b of CFG 20 are both
illustrated. In the zero-force case the relative phase
.phi..sub.2-.phi..sub.1 is 180 degrees and resulting force rotating
vector 26 has a magnitude of zero. In the full-force case, the
relative phase .phi..sub.2-.phi..sub.1 is 0 degrees and resulting
rotating force vector 26 has a maximum magnitude of 2|F|. For
relative phases .phi..sub.2-.phi..sub.1 between 0 and 180 degrees,
the magnitude of resulting rotating force vector 26 will be between
zero and maximum. Furthermore, the collective phase .gamma. of
rotating force vector 26 can be varied to provide phasing between
CFGs 20. Through control of phase .phi. of each imbalance mass 32a,
32b the magnitude and absolute phase of the rotating force vector
26 produced by CFG 20 can be controlled.
[0041] Referring to FIGS. 1-8C, the particular structure carrying
CFGs 20 includes n vibration sensors 30 and m CFGs 20, wherein
n.gtoreq.m and (with m whole number equal to or greater than one).
Controller 22 detects at least one vibration signal from at least
one vibration sensor 30, the vibration signal providing a
magnitude, a phase, and a frequency of the detected vibration.
Controller 22 generates a vibration reference signal from the
detected vibration data and correlates it to the relative vibration
of the particular structure carrying CFGs 20 relative to the CFGs
20.
[0042] Preferably, the first CFG 20 includes the first imbalance
mass 32a controllably driven about a first mass axis 42 with a
first controllable imbalance phase .phi..sub.1 and a second
imbalance mass 32b controllably driven about a second mass axis 44
with a second controllable imbalance phase .phi..sub.2, the first
controllable imbalance phase .phi..sub.1 and the imbalance phase
.phi..sub.2 controlled in reference to the vibration reference
signal. The m.sup.th CFG 20 includes a first imbalance mass
(mass.sub.m.sub.--.sub.1) 32a controllably driven about a first
mass axis 42 with a first controllable imbalance phase and a second
imbalance mass 32b controllably driven about a second mass axis 44
with a second controllable imbalance phase, the imbalance phase and
the imbalance phase controlled in reference to the vibration
reference signal. The vibration reference signal is typically an
artificially generated signal within the controller and is
typically a sine wave at the desired operational frequency.
[0043] Referring to FIGS. 5A-8, CFG 20 includes a first imbalance
mass 32a with a first controllable imbalance phase .phi..sub.1 and
a second imbalance mass 32b with a second controllable imbalance
phase .phi..sub.2. The first imbalance mass 32a is driven with
first motor 38a and second imbalance mass 32b is driven with second
motor 38b.
[0044] Referring to FIGS. 6 and 7, an embodiment implementing CFG
20 as two identical, but separate, units 46 is illustrated. Each
unit 46 contains a single imbalanced mass 32 driven by a single
motor 38. By positioning the two units 46 in close proximity, the
functionality of CFG 20 is achieved. FIGS. 6 and 7 show additional
embodiments of CFG 20. In these figures, only one of two units 46
comprising CFG 20 is shown. The same basic elements previously
described are identified in the embodiments shown in FIGS. 6 and 7.
Two units 46 may be applied to a mechanical device in proximity to
one another to enable CFG 20. For example, two units 46 may be
applied coaxially on either side of mounting plate to enable CFG 20
as illustrated in FIG. 9. In another example illustrated in FIG.
10, two units 46 are mounted non-coaxially side-by-side to enable
CFG 20.
[0045] Other embodiments of the current invention will be apparent
to those skilled in the art from a consideration of this
specification or practice of the invention disclosed herein. Thus,
the foregoing specification is considered merely exemplary of the
current invention with the true scope thereof being defined by the
following claims.
* * * * *