U.S. patent application number 11/985142 was filed with the patent office on 2008-06-19 for motion monitor.
Invention is credited to Edward Miesak.
Application Number | 20080146366 11/985142 |
Document ID | / |
Family ID | 39528038 |
Filed Date | 2008-06-19 |
United States Patent
Application |
20080146366 |
Kind Code |
A1 |
Miesak; Edward |
June 19, 2008 |
Motion monitor
Abstract
A method for evaluating the motion of a moveable object relative
to a reference object includes locating the reference object within
a three-dimensional coordinate system having first, second, and
third positional coordinates such that the position of the
reference object is characterized by respective values of first,
second, and third positional coordinates. A mechanism is provided
having a plurality of visual indicators. A sensor is configured to
detect the position of the moveable object within the
three-dimensional coordinate system substantially apart from any
dynamic property inherent in the movement of the moveable object.
An acceptable minimal number of sampling events is determined and
providing a sensor having sufficient response rate as to be capable
of determining respective positions of the moveable object as the
moveable object moves relative to the reference object such that
the number of the respective positions exceeds the acceptable
minimal number for any maximum velocity of the moveable object
manually achievable by the user.
Inventors: |
Miesak; Edward; (Windermere,
FL) |
Correspondence
Address: |
CHERNOFF, VILHAUER, MCCLUNG & STENZEL
1600 ODS TOWER, 601 SW SECOND AVENUE
PORTLAND
OR
97204-3157
US
|
Family ID: |
39528038 |
Appl. No.: |
11/985142 |
Filed: |
November 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60874320 |
Dec 13, 2006 |
|
|
|
Current U.S.
Class: |
473/221 ;
473/409 |
Current CPC
Class: |
A63B 2220/30 20130101;
G01P 3/00 20130101; A63B 2209/08 20130101; A63B 69/3614 20130101;
A63B 24/0003 20130101; A63B 2220/89 20130101; A63B 2220/36
20130101; A63B 2220/803 20130101; G01P 3/66 20130101 |
Class at
Publication: |
473/221 ;
473/409 |
International
Class: |
A63B 69/36 20060101
A63B069/36 |
Claims
1. A method for evaluating the motion of a moveable object relative
to a reference object comprising: (a) locating said reference
object within a three-dimensional coordinate system having first,
second, and third positional coordinates such that the position of
said reference object is characterized by respective values of said
first, second, and third positional coordinates; (b) providing a
mechanism having a plurality of visual indicators; (c) providing a
sensor configured to detect the position of said moveable object
within said three-dimensional coordinate system substantially apart
from any dynamic property inherent in the movement of said moveable
object; (d) determining an acceptable minimal number of sampling
events and providing a sensor having sufficient response rate as to
be capable of determining respective positions of said moveable
object as said moveable object moves relative to said reference
object such that the number of said respective positions exceeds
said acceptable minimal number for any maximum velocity of said
moveable object manually achievable by said user.
2. The method of claim 1 wherein said moveable object is the head
portion of a golf club.
3. The method of claim 1 wherein said reference object is a golf
ball.
4. The method of claim 1 wherein said offset and said array of said
first one of said indicators are linear.
5. The method of claim 1 wherein said dynamic property is an angle
of approach based on the angle between an axis of intended
trajectory of said reference object and an axis of motion of said
moveable object as said moveable object closely approaches said
reference object as evaluated with each said axis being projected
onto a common plane within said three dimensional coordinate
system.
6. The method of claim 1 wherein said sensor detects high frequency
movements.
7. The method of claim 1 wherein said sensor detects low frequency
movements.
8. The method of claim 1 wherein said sensor detects zero frequency
movements.
9. The method of claim 1 wherein said sensor proves an output that
is independent of object speed.
10. The method of claim 1 wherein said sensors are positioned
related to one another to detect multi-dimensional movements.
11. The method of claim 1 wherein said multi-dimensional movements
are orthogonal.
12. The method of claim 1 wherein said movements are linear
orthogonal.
13. The method of claim 1 wherein said movements are rotational
orthogonal.
14. The method of claim 1 wherein said movements include nine
orthogonal linear components and nine orthogonal rotational
components.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims be the benefit of U.S. Provisional
App. No. 60/857,125, filed Nov. 7, 2006, and U.S. Provisional App.
No. 60/874,320, filed Dec. 13, 2006.
BACKGROUND OF THE INVENTION
[0002] The present invention obtains movement information about the
movement of a mechanical device.
[0003] In many cases it is desirable to obtain movement information
about the motion of a golf club head in order to be able to
properly modify its swing.
[0004] The foregoing and other objectives, features, and advantages
of the invention will be more readily understood upon consideration
of the following detailed description of the invention, taken in
conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0005] FIG. 1 illustrates a six dimensional coordinate system.
[0006] FIG. 2 illustrates movement through a sensor detection
range.
[0007] FIG. 3 illustrates a typical sensor output.
[0008] FIG. 4 illustrates constant distance movement within a
sensor detection range.
[0009] FIG. 5 illustrates two overlapping sensor ranges.
[0010] FIG. 6 illustrates three overlapping sensor ranges.
[0011] FIG. 7 illustrates a golf swing monitor.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
[0012] A data acquisition system (DAQ) may be used to capture the
vector movement (magnitude and direction) of an object traversing a
complex path in three dimensions and extract the constituent
movements into a six dimensional coordinate space (or other number
of dimensions). A golf club swing is used as an illustrative
example of a complex mechanical movement. A three dimensional (3D)
Cartesian coordinate axes (X, Y, Z) is shown in FIG. 1. The golf
club head swings primarily along the direction of the Z axis. The Y
axis is in the vertical direction representing the height of the
club above the ground, and the X axis represents the side-to-side
(S2S) position of the club. The origin of the axes is centered on
the golf ball, i.e. the center of the ball is located at the
intersection of the X, Y, and Z axes. Each axis has a linear and
rotational movement associated with it. Linear movements are
measured along each axis while rotational movements are measured
about each axis. The three axes times the two movements (linear,
rotational) produces the six dimensional measurement space
described above.
[0013] Complex mechanical movement can be decomposed into a set of
orthogonal (independent) component (constituent) movements. The
original movement can be reconstructed from these component
movements by adding them back together into a "superposition." The
data acquisition system (DAQ) may capture and decompose a complex
mechanical movement into orthogonal linear and rotational
components. The coordinate axes system used here is a three
dimensional Cartesian coordinate system (three orthogonal axes X,
Y, Z). Any valid coordinate system may be used with this
application, i.e., cylindrical, spherical, etc.
[0014] Movement along any one axis of a Cartesian coordinate system
is independent of the other two axes. In other words, a movement
directly along the X axis for example, is not visible on the Y or Z
axes. This is advantageous to a user who needs to investigate
individual components of a complex movement. For example, this
could be applied to the area of analyzing a golf club swing. A golf
club, during normal use, travels through a three dimensional space
in a highly complex manner, i.e. it has many linear and rotational
components along multiple axes. Decomposing such a complex movement
into basic constituents (i.e., head rotation about the vertical
axis, head velocity along the direction of the swing, etc.) greatly
simplifies the task of improving the complete golf club swing
because the user can isolate a component of the swing giving
him/her trouble and work on it.
[0015] Every movement (linear, rotational) is described by three
related quantities, position, velocity, acceleration (PVA). Each of
these can be represented mathematically in the time domain as x(t)
(position), v(t) (velocity), and a(t) (acceleration.) They are
related through the definitions,
v ( t ) = x t , ##EQU00001##
a ( t ) = v t . ##EQU00002##
Each of these quantities (PVA) can be positive, zero, or negative.
Because they are mathematically related to each other, measuring
one can produce the other two.
[0016] A complicated vector movement of an object traveling through
a three dimensional space can be described by providing values for
each of the 6D coordinate space components of the object's
movement. The total number of components required to produce a
complete description is three linear axes (X, Y, Z) plus three
rotational axes (X, Y, Z) times three quantities (PVA) or
eighteen.
[0017] The data acquisition system (DAQ) are designed specifically
to allow accurate movement decomposition. The sensors should have
the capability of producing data rich enough in content from which
the software can extract the 6D components. These two pieces of the
DAQ (hardware, software) should be designed together in order to
function well.
[0018] For purposes of explanation here the complex mechanical
movement being captured, recorded, and deconstructed, will be
produced by a golf club during normal play or practice. The system
tracks the movement of a mechanical object through space with
respect to time. The movement is recorded then dissected into six
dimension (6D) parameters (described above) in order to provide a
deep understanding of the complex movement for the user.
[0019] Sensors are used to track the complex movement of an object.
In order for this system to function properly there are minimum
requirements on the sensors. They need to be able to respond fast
enough to capture much of the high frequency component of the
movement. They also should be able to capture the low frequency
component, typically a stationary position. The output of a sensor
should depend only on the distance of the object from the sensor
and not on the speed of the object moving past the sensor. This
characteristic allows the system to measure speed and distance
independently.
[0020] Referring to FIG. 2, an object traveling through the range
of a sensor, shown as a hemisphere, will produce a signal dependent
on the distance to the sensor. When the object first enters the
sensor range a weak signal is produced. As the object continues to
travel towards the sensor the signal strength continues to
increase. At the point where the object is closest to the sensor
the signal reaches its maximum value. As the object travels away
from the sensor the signal strength decreases. The signal returns
to zero when the object leaves the range of the sensor.
[0021] In order to create an accurate temporal snapshot of the
movement of an object through the sensor detection range some
technique of data collection with memory should be employed. A
micro-controller (.mu.C) can be used to create such a picture in
time. A .mu.C having all the necessary components to collect and
store sensor data may be used. A technique of adapting the sensor
output signal to a .mu.C input is utilized. For instance, many
sensors have analog outputs. A .mu.C having an analog to digital
converter (ADC) is easily found. Simple electronic interface
circuitry insures that the sensor output signal is compatible with
the .mu.C input circuit. The .mu.C can be programmed to collect and
store sensor signals at known time intervals. All the sensor
signals are stored such that the time of occurrence of each signal
is known. The sensor signals can be read-out in correct order to
create an accurate temporal picture of the sensor signal.
[0022] Referring to FIG. 3, as an example, the graph illustrates an
actual sensor output of a mechanical object traveling on a straight
line path through the sensor detection range. More than 200 samples
of the sensor output were collected and stored during the object's
travel. The samples are treated as a single quantity because they
all reside in a single file. This file is available to be processed
by the .mu.C at some later time.
[0023] Typically the sensors are sampled many times in rapid
succession. These samples are then assembled to create a virtually
continuous picture in time of the sensor signal. This provides the
necessary accuracy and richness of information that allows more
than one quantity to be extracted from each sensor, i.e., peak
amplitude, average amplitude, pulse width, etc., during
post-processing.
[0024] A single sensor can typically discern only the distance to
an object, not the path taken. For instance, if an object travels
at a constant distance from the sensor within its sensing range the
sensor will produce a constant signal. Referring to FIG. 4, as an
example, a sensor is illustrated with a circular path (broken line)
above it at a constant distance from it. If an object is anywhere
on this line either stationary or traveling at a constant or
varying speed, the output signal from the sensor will always be the
same value. The sensor can only detect distance. Since the distance
is constant the signal is also constant. This is an ambiguous
situation. The position, velocity, and acceleration (PVA) of the
object are unknown.
[0025] A top-down view of the sensor detection range is a circle
with the sensor at the center. The only information that can be
determined when an object is sensed inside this circle is the
distance from the sensor. Adding a second sensor provides
additional information which can be used to reduce the PVA
ambiguity. The two sensors are placed so that their detection
ranges overlap each other. If the two sensors are placed in the
same plane, a top-down view of their sensing range would be two
over lapped circles, as is shown in FIG. 5.
[0026] The single cross-hatched area between the two sensors (Sn1,
Sn2) is where the two detection ranges overlap. If the object being
tracked is in this area additional information about its PVA can be
obtained by comparing the output signals from Sn1 and Sn2. The PVA
of the object along the direction of the line B-B within the single
cross-hatched area can be determined. A third sensor is added in
order to remove the PVA ambiguity along the direction of the line
A-A. The optimum location for this third sensor would be directly
on the line A-A though it could also reside else where (as long as
it's not on the line B-B).
[0027] Referring to FIG. 6, an illustration of using three sensors
is shown. The layout begins with the two sensor configuration shown
above then adds a third sensor (Sn3) on the line A-A. This allows a
triangulation of the signals in order to determine the object PVA
within the double cross-hatched area. Using three sensors may be
adequate for one application but not for another. Each application
is analyzed in order to determine the optimum sensor quantity,
placement, and software deconstruction semantics. This places
responsibility on the designer to create a sensor layout and
software design together that will work for a particular
application. A special application would be a golf swing
monitor.
[0028] When used to monitor the movement of a golf club head during
a swing one preferred embodiment places the sensors in the
immediate vicinity of the golf ball. This could be due to a limited
sensor detection range. This motion (swing) monitor would also
contain a display for the user. FIG. 7 shows one embodiment of a
swing monitor. In the illustration the display area is denoted by
the recessed area around the golf ball. The sensors reside under
the golf ball. The swing monitor is placed on the ground with the
display facing the user. The user places a golf ball on it in a
pre-determined location then hits the ball in a normal fashion. A
golf ball tee may or may not be used with the swing monitor. The
display on the surface shows properties of the swing that resulted
in the vicinity of the ball.
[0029] The motion monitor would be battery operated and completely
self sufficient, i.e. it would not need to be interfaced to a
laptop or desktop computer in order to operate. The .mu.C on board
the system is capable of providing all the functions necessary for
the system to operate. The small size and self-sufficiency allows
this motion monitor to be highly portable and very useful in almost
any location.
[0030] One type of sensor that could be used with a swing monitor
is a Hall effect magnetic sensor. This type of sensor has the
sensor properties stated above, i.e.:
[0031] a. High frequency response.
[0032] b. Zero frequency response.
[0033] c. Output signal depends only on the distance to the magnet,
not velocity.
[0034] This sensor should include a magnet to be attached to or
installed inside of the golf club head.
[0035] Some types of magnetic sensors will only operate when the
magnet is moving, (i.e., they will not sense a stationary magnet)
these can be called dynamic sensors. These sensors typically
contain a loop of wire or an induction coil. These sensors are
typically sensitive to two parameters simultaneously, proximity and
velocity. A single reading by one of these sensors will be the
result of both the velocity of the magnet and the distance of the
magnet to the sensor. This type of sensor would not be optimum for
a golf swing monitor.
[0036] The sensors chosen for the swing monitor of this example
will operate with non-moving magnets, i.e. they will sense a
stationary magnet as well as a moving magnet. These can be referred
to as base-band sensors. These sensors are not sensitive to the
magnet velocity as it passes the sensor, only proximity. These two
properties are useful because they allow a minimum number of
sensors to detect a maximum number of movement properties. For
instance, when the user is "addressing the ball" the club is not
swinging, it is being placed in a stationary position behind the
golf ball prior to the swing. Base-band sensors will be able to
acquire the static position/orientation of the golf club in this
instance whereas dynamic sensors will not. When a swing is made the
base-band sensors will also be able to record the moving club.
[0037] Magnetic sensors are not the only type that will work with
this motion monitor. Any sensor that possesses the above described
characteristics and has an acceptable range of detection can be
made to work. But not every sensor is easy to work with, or has to
optimum price range, or power requirements, or size.
[0038] The sensors in this example motion monitor lie underneath
the golf ball in a flat plane. The position of each sensor is
defined by the size and strength of the magnet on the moving object
(in this case a golf club.) There is an optimum position for each
sensor depending on which parameter is being sensed. In order to
simultaneously collect as many of the 6D parameters as possible,
compromises have to be made on the positions of all the sensors
together. Deconstructing software is then appropriately
designed.
[0039] The micro-controller (.mu.C) portion of the DAQ will collect
all the sensor information, store it, and process it. Processing
involves extracting 6D components of the complex movement for
display. The .mu.C can also drive (control) the display.
[0040] Sensor signal acquisition occurs through continuous sampling
over time. Each sensor signal is recorded and stored in an array
long enough to contain all the vital characteristics of the
movement. A single array contains a continuous picture of the
sensor signal in time. After the movement has been recorded it is
processed to extract the basic components making it up. These 6D
components are displayed for the user to see. The movement
components are often more valuable to the user than the complex
motion itself.
[0041] The terms and expressions which have been employed in the
foregoing specification are used therein as terms of description
and not of limitation, and there is no intention, in the use of
such terms and expressions, of excluding equivalents of the
features shown and described or portions thereof, it being
recognized that the scope of the invention is defined and limited
only by the claims which follow.
* * * * *