U.S. patent application number 10/954711 was filed with the patent office on 2005-09-29 for position detector and method of motion analysis.
Invention is credited to Marquardt, Christian.
Application Number | 20050215335 10/954711 |
Document ID | / |
Family ID | 34957112 |
Filed Date | 2005-09-29 |
United States Patent
Application |
20050215335 |
Kind Code |
A1 |
Marquardt, Christian |
September 29, 2005 |
Position detector and method of motion analysis
Abstract
The invention relates to a position detector (3) for a method of
motion analysis, especially for golf training. It is proposed that
the position detector (3) be detachably mounted on a ball sport
device (2) and then receive and transmit at least one position
signal for the determination of the spatial position and/or the
alignment of the ball sport device (2). Furthermore, the invention
includes a method of motion analysis by using the position detector
according to the invention.
Inventors: |
Marquardt, Christian;
(Munich, DE) |
Correspondence
Address: |
Becker & Poliakoff, P.A.
3111 Stirling Road
Fort Lauderdale
FL
33312
US
|
Family ID: |
34957112 |
Appl. No.: |
10/954711 |
Filed: |
September 30, 2004 |
Current U.S.
Class: |
473/131 |
Current CPC
Class: |
A63B 2220/05 20130101;
A63B 2220/89 20130101; A63B 2220/802 20130101; A63B 69/3632
20130101; A63B 2220/805 20130101; A63B 69/3685 20130101; A63B
2220/806 20130101 |
Class at
Publication: |
473/131 |
International
Class: |
A63B 057/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2004 |
WO |
PCT/EP04/03237 |
Claims
I claim:
1. Position detector (3) characterized by a mounting arrangement
with which the position detector (3) can be detachably mounted on a
ball sport device (2).
2. Position detector (3) according to claim 1, characterized in
that the ball sport device (2) is a golf club.
3. Position detector (3) according to one of the preceding claims,
characterized by at least one transmitter (7, 9, 10) for emitting a
position signal to a stationary receiver (16-18), wherein the
receiver (16-18) determines the position and/or the alignment of
the ball sport device (2), dependent upon the received position
signal.
4. Position detector (3) according to claim 3, characterized by at
least three, interspaced transmitters (7, 9, 10), each of which
emits a position signal to three stationary and interspaced
receivers (16-18).
5. Position detector (3) according to claim 1 or 2, characterized
by at least one receiver for receiving the position signal from a
stationary transmitter, wherein the receiver determines the
position and/or the alignment of the ball sport device, dependent
upon the received position signal.
6. Position detector (3) according to claim 5, characterized by at
least three, interspaced receivers, each of which receives a
position signal from three stationary and interspaced
transmitters.
7. Position detector (3) according to one of the claims 3 to 6,
characterized in that the transmitter (7, 9, 10) is an ultrasonic
transmitter.
8. Position detector (3) according to one of the claims 3 to 7,
characterized in that the transmitters (7, 9, 10) are essentially
arranged on one plane (flush).
9. Position detector (3) according to one of the claims 3 to 8,
characterized in that the transmitters (7, 9, 10) essentially emit
the position signals in the same direction.
10. Position detector (3) according to one of the claims 3 to 9,
characterized in that the three transmitters (7, 9, 10) are
essentially arranged in the shape of a triangle.
11. Position detector (3) according to one of the claims 3 to 10,
characterized in that one of the transmitters (7, 9, 10) is
arranged, in the mounted state, flush with the shaft of the ball
sport device (2), while the two other transmitters (9, 10) are
arranged on opposite sides of this plane.
12. Position detector (3) according to claim 1 or 2, characterized
in that the position detector has at least one acceleration
sensor.
13. Position detector (3) according to one of the claims 2 to 12,
characterized in that the position detector (3) can be mounted on
the shaft of the ball sport device (2).
14. Position detector (3) according to one of the preceding claims,
characterized in that a cable connection (11) is provided for wire
communication with a stationary control unit (12).
15. Position detector (3) according to one of the preceding claims,
characterized in that an additional transmitter is provided for
wire communication with a stationary control unit (12).
16. Position detector (3) according to claim 15, characterized in
that the additional transmitter can be attached to the body of a
golfer.
17. Motion-analysis system with a position detector (3) according
to one of the preceding claims and a control unit (12) that is
connected to the position detector (3) in order to control and
assess the motion analysis.
18. Method of motion analysis, characterized in that the motion of
the ball sport device (2) during a swing is recorded and analyzed
by a position detector (3) mounted on the ball sport device
(2).
19. Method of motion analysis according to claim 18, characterized
in that the ball sport device (2) is a golf club.
20. Method of motion analysis according to one of the claims 18 to
19, characterized by the following steps: transmission of a
position signal between the position detector (3) mounted on the
ball sport device (2) and a stationary control unit (12),
determination of the position and/or the alignment of the ball
sport device (2), dependent upon the position signal.
21. Method of motion analysis according to claim 20, characterized
in that the transit time of the position signal between the
position detector (3) and the control unit (12) is measured, and
then the position and/or alignment of the ball sport device (2) is
determined using the transit time.
22. Method of motion analysis according to claim 20 or 21,
characterized in that the position detector (3) and the control
unit (12) have several interspaced transmitters (7, 9, 10) or
several interspaced receivers, among which several position signals
are transmitted, wherein the position and/or the alignment of the
ball sport device (2) is determined, dependent upon the position
signals.
23. Method of motion analysis according to one of the claims 18 to
22, characterized in that the following data are determined from
the position and/or the alignment of the ball sport device (2):
start of a swing motion and/or end of a swing motion and/or moment
of impact of the ball sport device (2) on the ball.
24. Method of motion analysis according to one of the preceding
claims, characterized in that at least one of the following swing
parameters is determined for a swing from the position and/or the
alignment of the golf club (2): duration of backswing duration of
follow-through impact time symmetry of the impact time symmetry of
the velocity profile alignment when addressing the ball club head
at the moment of impact differential value for alignment rotation
to the moment of impact rotation after the moment of impact
rotation rate per time horizontal angle of the club head on the
swing path loft of the club at the moment of impact point of impact
on the club head height of club at moment of impact length of
backswing length of follow-through symmetry of swing path
horizontal direction of the swing path at the moment of impact
vertical incline of the swing path at the moment of impact maximum
backswing velocity velocity at impact maximum follow-through
velocity maximum acceleration acceleration after impact maximum
braking average jerk during the backswing average jerk during the
follow-through.
25. Method of motion analysis according to one of the claims 18 to
24, characterized in that the variability is calculated for each of
the swing parameters in order to measure motion consistency.
26. Method of motion analysis according to one of the claims 18 to
25, characterized in that the swing parameters are graphically
displayed.
27. Method of motion analysis according to one of the claims 18 to
26, characterized in that the chronological sequence of the swing
parameters is graphically displayed.
28. Method of motion analysis according to one of the claims 24 to
27, characterized in that the swing parameters are normalized.
29. Method of motion analysis according to one of the claims 18 to
28, characterized in that the swing parameters are compared to
stored reference values and/or displayed together with the
reference values.
30. Method of motion analysis according to one of the claims 28 to
29, characterized in that an Overall-Performance-Index is
calculated from the normalized swing parameters in order to
determine the performance of the golfer.
31. Method of motion analysis according to one of the preceding
claims, characterized in that, in addition to the position
determination of the club, other position signals, such as, the
positions and motions of the golfer's body, are synchronously
recorded and jointly analyzed.
32. Method of motion analysis according to one of the preceding
claims, characterized in that, in addition to the position
determination of the club, the ground reaction forces during golf
play are synchronously measured and analyzed using a force
measuring plate.
33. Method of motion analysis according to one of the claims 18 to
32, characterized in that motion problems, such as the Yips
Syndrome, can be classified and identified already before they
actually occur by using the calculated competency profile.
34. Method of motion analysis according to one of the claims 18 to
33, characterized in that the position detector has at least one
acceleration sensor that produces an acceleration signal
corresponding to the motion of the ball sport device.
35. Method of motion analysis according to claim 34, characterized
in that the position signal that is dependent upon the transit time
is balanced with the acceleration signal, in order to increase the
precision.
36. Method of motion analysis according to claim 34, characterized
in that the position signals and the angle signals of the club are
reconstructed from the acceleration signals, in order to calculate
the swing parameters from them.
Description
[0001] The invention relates to a position detector, as well as to
a method of motion analysis.
[0002] In the game of golf, putting requires highly-developed fine
motor skills from the players. During training, primary attention
is normally focused on the driving technique, that is, on the
static aspects of motion. During putting, the dynamics of motion
can hardly be perceived with the naked eye due to the extremely low
execution speed. Likewise with conventional methods of analysis,
such as video analysis, the dynamic aspects of putting movements
have, for methodological reasons, been analyzable only
unsatisfactorily and with great difficulty. Correspondingly, the
training of the short game is often quite neglected and frequently
leads to unsatisfactory results, although putting makes up
approximately 40% of the golf game when measured by the number of
strokes.
[0003] The task of the invention is therefore to measure and
improve the sequence of movements during the golf game, and
especially during putting.
[0004] This task is accomplished by means of a position detector
according to claim 1 and by a corresponding method of motion
analysis according to claim 18.
[0005] The invention is based on the knowledge that, when learning
slow movements such as putting, unnoticed systematic motion errors
are also frequently learned. The execution of quick ballistic
motions is always purely motor-driven and, therefore,
self-organizing. In contrast to this, the execution of slow motions
is always closely tied to strategy. Strategic motion errors during
slow motions, such as those performed during putting, frequently go
unnoticed by the golfers themselves; and it is difficult even for
trainers to recognize these mistakes with the naked eye. For
example, in the sport of golf, the so-called Yips syndrome leads to
an unconscious twitching of the hand and wrist during the short
game and thus makes precise execution of the swinging motion
impossible. Yips syndrome cannot be alleviated with conventional
training methods; quite the contrary, the symptoms continue to
worsen with intensified practice.
[0006] The invention therefore comprises a general technical gauge
for recording and analyzing the movement of a golf club using a
suitable device-supported method of motion analysis. The strengths
and weaknesses of the individual sequence of movements are hereby,
on the one hand, displayed in detail, enabling targeted, and thus
extremely efficient, training. Furthermore, motion problems, such
as the Yips syndrome, can be measured early and objectively. By
using the derived information, a specific treatment for these
motion problems can be carried out for the first time.
[0007] In addition to this, within the framework of the invention,
a position detector is provided that is detachably mounted on a
golf club for the purpose of determing the spatial position and/or
the alignment of the club.
[0008] Preferably, the position detector receives and transmits at
least one position signal, which serves to determine the position
and/or the alignment of the golf club.
[0009] The invention is not, however, limited to recording the
position or alignment of a golf club, but can rather basically be
used for other ball sport devices, such as, for example, billiards,
cricket bats, or similar clubs. To facilitate understanding,
however, the invention will be described below using a golf
club.
[0010] The position detector is preferably an active position
detector that transmits at least one position signal that is
recorded by a stationary receiver, wherein the position and/or the
alignment of the golf club is determined by the receiver dependent
upon the received position signal.
[0011] Another alternative, however, is a position detector,
mountable on the golf club, that is passive and has a receiver for
receiving a position signal from a stationary transmitter, wherein
the position and/or the alignment of the golf club is again
determined by the receiver dependent upon the position signal.
[0012] The position signal is preferably an ultrasonic signal that,
for example, can be transmitted with a measurement rate of between
100 Hz and 400 Hz, wherein the measurement rate in the preferred
embodiment of the invention amounts to 300 Hz. The use of an
ultrasonic signal as the position signal enables a high-sensitivity
resolution of approximately 0.1 mm, which, during motion analysis,
can expose the smallest details of the sequence of movements and
also enable the identification of motion disturbances, such as, for
example, Yips syndrome, which are invisible to the naked eye.
[0013] With regard to the position signal, however, the invention
is not limited to an acoustical signal. The position signal can
rather be an optical or a magnetic signal. In this regard, the
motion-measuring components can--for example, according to the
principle of optical position determination--consist of cameras or
laser-light scanning; and the measuring sensors can be made of
reflecting and/or actively ruminating marking dots and optically
sensitive measuring surfaces. Furthermore, according to the
principle of position determination, the motion-measuring
components can function by using magnetic fields.
[0014] In addition to this, the position detector can also have one
or more acceleration sensors that record the movement of the golf
club.
[0015] In the preferred embodiment of the invention, the position
detector that can be mounted on the golf club has at least three
transmitters or receivers, so that the position of the individual
transmitters or receivers can be precisely determined by
triangulation and subsequently coordinate transformation. The
individual transmitters or receivers are hereby preferably arranged
on a common plane and form a triangle.
[0016] Furthermore, it is preferable for the individual
transmitters to emit essentially in the same direction, wherein the
individual transmitters can have a transmission angle of up to
180.degree., so that the position detector or an associated control
unit must be only approximately aligned with the associated
receivers.
[0017] When the position detector is in the mounted state according
to the invention, one of the transmitters is preferably arranged
flush with the shaft of the golf club, while the other two
transmitters are arranged on opposite sides of this plane. This
arrangement of the individual transmitters advantageously enables a
simple and precise coordinate transformation and, thus, precise
position determination.
[0018] The position detector according to the invention is
preferably mounted on the shaft of the golf club, wherein the
mounting is detachable and, for example, can be performed with a
clamping screw joint. The position detector is hereby preferably
rotatable around the shaft of the golf club, wherein a gauge can be
used for aligning the position detector in the rotation direction
relative to the golf club.
[0019] The detachable mounting of the position detector according
to the invention that is on the golf club is advantageous because
the position detector is also a training device, and different golf
clubs can be compared to one another. For example, testing
different golf clubs with the position detector according to the
invention enables the direct selection of the individually optimal
golf club, which otherwise is possible only with a longer use of
different golf clubs.
[0020] The actual determination of the position or alignment of the
golf club is hereby preferably performed via a stationary control
unit, wherein the control unit is connected to the transmitters and
the receivers in order to perform a transit time measurement and
thus determine the position and alignment of the position detector
and the golf club to which the position detector is attached. A
conventional control unit, such as, for example, the one marketed
by zebris Medical GmbH, Max-Eyth-Weg 42, 88316 Isny (Germany) under
the brand name CMS-20 or CMS10, can be used for this.
[0021] Within the framework of the method of motion analysis
according to the invention, the raw data from the aforementioned,
well-known control unit, however, undergoes a kinematic analysis in
order to acquire golf-specific information on golf training and,
particularly, on the training of putting. For example, from the
position and/or the alignment of the golf club, the following swing
parameters can be determined:
[0022] duration of backswing
[0023] duration of follow-through
[0024] impact time
[0025] symmetry of the impact time
[0026] symmetry of the velocity profile
[0027] alignment when addressing the ball
[0028] club head at the moment of impact
[0029] differential value for alignment
[0030] rotation to the moment of impact
[0031] rotation after the moment of impact
[0032] rotation rate per time
[0033] horizontal angle of the club head on the swing path
[0034] loft of the club at the moment of impact
[0035] point of impact on the club head
[0036] height of club at moment of impact
[0037] length of backswing
[0038] length of follow-through
[0039] symmetry of swing path
[0040] horizontal direction of the swing path at the moment of
impact
[0041] vertical incline of the swing path at the moment of
impact
[0042] maximum backswing velocity
[0043] velocity at impact
[0044] maximum follow-through velocity
[0045] maximum acceleration
[0046] acceleration after impact
[0047] maximum braking
[0048] average jerk during the backswing
[0049] average jerk during the follow-through.
[0050] Additionally, within the framework of the method of motion
analysis according to the invention, the variabilities of all
twenty-eight (28) parameters are preferably calculated for multiple
swings (typically, 5 swings), in order to describe the consistency
of motion execution.
[0051] Furthermore, the individual swing parameters are preferably
normalized within the framework of the method of motion analysis
according to the invention, so that deviations from the norm within
the individual swing parameters can be easily recognized and
quantitatively evaluated.
[0052] In addition to this, the swing parameters are preferably
graphically depicted within the framework of the method of motion
analysis according to the invention, wherein the depiction can be
performed with stored comparative values so that deviations and
motion disturbances can be recognized.
[0053] Other advantageous improvements of the invention are
described in the dependent claims or, together with the following
description of the prefered embodiment of the invention, are
discussed in more detail using the figures. Shown are:
[0054] FIG. 1 a motion-analysis system according to the invention
for the training of putting in golf,
[0055] FIG. 2 a position detector according to the invention that
can be mounted on a golf club,
[0056] FIG. 3 an enlarged view from FIG. 1 with the position
detector from FIG. 2 mounted on the golf club,
[0057] FIGS. 4a to 4e the method for motion analysis according to
the invention in a flowchart,
[0058] FIGS. 5 and 6 different graphic renditions on the monitor
that are generated within the framework of the method for motion
analysis according to the invention, as well as
[0059] FIG. 7 an alternative embodiment of a motion-analysis system
according to the invention.
[0060] FIG. 1 shows a golfer 1 putting with a golf club 2, wherein
an active position detector 3, which is shown in detail in FIG. 2
and subsequently described, is detachably mounted on the shaft of
the golf club 2.
[0061] The position detector 3 has two attachment screws 4, 5 with
which the position detector 3 can be detachably mounted on the
shaft of the golf club 2. The alignment of the position detector 3
in the rotation direction around the shaft of the golf club 2 is
hereby accomplished by a gauge, which, for reasons of
simplification, is not shown.
[0062] The position detector 3 essentially consists of a middle
part 6, on whose free end an ultrasonic transmitter 7 is attached,
wherein the middle part 7 branches out on the opposite end into two
side arms 8.1, 8.2, on whose free ends another ultrasonic
transmitter 9 or, respectively, 10, is attached in each
instance.
[0063] The ultrasonic transmitters 7, 9, 10 are hereby arranged on
a plane and emit in the same direction, wherein the individual
ultrasonic transmitters 7, 9, 10 have, in each instance, a
transmission angle of 180.degree. and a maximum measurement
distance of approximately 2 m and enable a measurement rate
totaling 300 Hz.
[0064] On the top of the position detector 3, there is a connection
to which a fourth sensor can be connected in order to separately
measure wrist motions. The motions of the wrist are very important,
especially when Yips problems are being measured.
[0065] Furthermore, the motion-analysis system can also process
other measuring signals, if a position detector attached to the
body of golfer 1 is used instead of position detector 3 on golfer
2. With such a position detector, other body movements, such as
movements of the head, shoulders, back, and hips, can also be
measured. In another embodiment of the invention, these
body-specific signals can be simultaneously registered with a
second measuring sensor that is connected to the same processor via
a second control unit. The signals from the motion of the golf club
2 and the motion signals of the body can be analyzed and evaluated
synchronously. With such a measuring unit, the connection between
good performance during the short golf game and the associated
body-specific movements can be measured for the first time.
Furthermore the motion-analysis system can be operated in
synchronization with other measuring systems, for example, for
performing a synchronous determination of the ground reaction
forces using a force-distribution measuring plate.
[0066] The position detector 3 is connected by a cable 11 to a
control unit 12, which can have a conventional design. For the
control unit 12, one can, for example, use the CMS10 or the CMS 20S
measuring system, which is marketed by the aforementioned company
zebras Medical GmbH.
[0067] The communication between the position detector 3 and the
control unit 12, however, can alternatively be wireless, for
example, it can be performed by an optical signal. In addition, a
signaling transmitter (e.g., infrared), which, for example, is
fastened to the belt of the golfer 1 and controls an additional
receiver, can be controlled via a shortened cable. The measuring
sensor is then preferably connected by a cable to the processor 19
via the control unit 12. The control unit 12 can hereby also be
integrated with the measuring sensor 14 or combined with the
processor 19.
[0068] Furthermore, the control unit 12 is connected by another
cable 13 to an ultrasonic measuring sensor 14, which can be
designed conventionally and is available, for example, together
with the aforementioned measuring system of zebras Medical GmbH.
The measuring sensor 14 is hereby arranged on a tripod and has
three ultrasonic receivers 16, 17, 18, which are arranged on a
single plane in the shape of a triangle and which are aligned,
jointly and roughly parallel, to the position detector 3, in order
to receive ultrasonic signals from the ultrasonic transmitters 7,
9, 10.
[0069] Via cable 11, the control unit 12 triggers the ultrasonic
transmitters 7, 9, 10 to emit ultrasonic impulses that are recorded
by the ultrasonic receivers 16-18 and transmitted via cable 13 to
the control unit 12. The transit times of the ultrasonic impulses
of the ultrasonic transmitters 7, 9, 10 until they are received by
the ultrasonic receivers 16-18 are transmitted by the measuring
sensor 14, via the cable 13, to the control unit 12 and, from
there, via a data interface, to the processor 19. Using
triangulation, the processor 19 calculates the positions of the
individual ultrasonic transmitters 7, 9, 10 in three-dimensional
space from the transit time of the ultrasonic impulses. From this
raw data, the processor 19 then calculates the position data of the
golf club 2 in real time by using coordinate transformation. The
position data of the golf club 2 are analyzed in real time, and the
results are alternately displayed on a monitor 20 and saved for
further analysis in a measured value file. Operator prompting is
hereby possible via an input device 21.
[0070] From the enlarged representation in FIG. 3, one can see that
the position detector 3 is attached to the shaft of the golf club 2
in such a way that the ultrasonic transmitter 7 is located in the
middle front of the shaft, while the side arms 8.1 and 8.2 stick
out laterally from the shaft of the golf club 2. This arrangement
of the position detector 3 enables a precise position determination
using a triangulation of the ultrasonic impulses that are emitted
by the three ultrasonic transmitters 7, 9, 10.
[0071] FIGS. 4a to 4e show the method of motion analysis according
to the invention in a flowchart. In the segment of the method shown
in FIG. 4a, preliminary tasks, such as the mounting of the position
detector 3 onto the golf club 2, as well as the set-up of the
measuring sensor 14 with the tripod 15 and the alignment of the
measuring sensor 14 in the direction of golfer 1, are initially
performed.
[0072] Furthermore, the entire system is calibrated in this segment
of the method, in order to enable a precise recording of the
position. For this, the club head of the golf club 2 is calibrated,
in the horizontal direction, precisely in the direction of the
sighted target ("alignment"), and, in the vertical direction, the
club head is calibrated in the direction of the the gradient
opposite the verticals ("loft").
[0073] In the segment of the method shown in FIG. 4b, the actual
measurement of the motion of golf club 2 is then performed, wherein
this segment of the method is constantly repeated in the background
during operation. During a measurement in the diagnosis mode,
several swings are normally performed one after the other, in order
to test the consistency of motion execution. Typically, there are
five putts to the same goal.
[0074] During this procedure, the ultrasonic transmitters 7, 9, 10
of the position detector 3 constantly emit ultrasonic signals that
are received by the ultrasonic receivers 16 to 18 of the measuring
sensor 14.
[0075] The control unit 12 then measures the transit time of the
ultrasonic signals between their emission by the ultrasonic
transmitters 7, 9, 10 of the position detector 3 and their
reception by the ultrasonic receivers 16 to 18 of the measuring
sensor 14.
[0076] Finally, from the measured transit times, the processor 19
calculates the positions of the ultrasonic transmitters 7, 9, 10,
and, from these positions, it calculates the position and alignment
of the club head using coordinate transformation, wherein a defined
alignment of the position detector 3 relative to the golf club 2 is
taken as the basis.
[0077] In order to make an operator intervention superfluous for
the measuring and storing of the data on individual swings, the
swing motions within the continuous data stream are automatically
identified according to precisely defined criteria, a task that is
performed in the segment of the method shown in FIG. 4c. For this,
diverse criteria are combined in a combination of time sequences,
motion direction, and motion dynamics. First, the golf club 2 must
be kept still for a certain period of time (for example, for 1
second). Then the club must be moved away from the goal in the
negative direction at a certain minimum velocity. Within a certain
period of time, the backward motion must then be stopped and
converted seamlessly into a forward motion. Within a certain period
of time, a certain forward velocity must then be exceeded. Within a
certain period of time, the swing velocity must then decrease to
below a certain threshold value, in order to indicate the end of
the stroke. If one of the specified conditions is not met, the
measurement cycle is interrupted, and the motion is rejected as
invalid.
[0078] If, on the other hand, a valid swing cycle was identified in
the continuous data stream, then the associated position data and
the alignment of the club head of golf club 2 are stored, along
with the respective measurement times for the subsequent analysis
of the swing motion.
[0079] If the swing motion did not end correctly, then the segment
of the method shown in FIG. 4c is repeated. If a swing is ended and
the required number of strokes have not yet been completed, then
the segment of the method shown in FIG. 4c is performed again.
Otherwise, one skips to the segment of the method shown in FIG. 4d
in which the actual analysis and display of the motion data is
performed as described below.
[0080] In contrast to the diagnosis mode, in the training mode,
only one motion is executed each time. This is immediately analyzed
in real time, and the results displayed on the monitor. Thus, the
golfer 1 can immediately see how close he or she has come to the
standard for each stroke. In contrast to the continuous
biofeedback, here a so-called kinetic feedback is used ("knowledge
of result"). Continuous motion feedback, on the other hand, would
disrupt motion execution; and it has proven to be unsuitable for
the learning of automated movements.
[0081] Before the data can be evaluated, they undergo an error
analysis and data filtering, which is shown in FIG. 4d. Since all
biomechanical signals entail a certain error ratio and this error
ratio is multiplied when dynamic aspects, such as, velocity and
acceleration, are calculated, then valid data filtering plays a
decisive role. On the basis of scientific findings, a sliding
average filter is used here that, as has been proven, produces the
best filtering results for motion data. This filter is described,
for example, in MARQUARDT, C. & Mai, N.: "A computational
procedure for movement analysis in handwriting" (Journal of
Neuroscience Methods, 52, 39-45); thus the entire contents of this
publication should be included in the existing description, and a
detailed description of the data filtering is not needed here.
[0082] Since the impact time of the golf club 2 on the golf ball
cannot be measured acoustically due to the low velocity of the
club, the moment of impact is calculated from the data stream. In
order to determine the impact time, a combination of the position
when the swing begins, the club height, and the measured impact
impulse of the ball on the golf club 2 is used in the acceleration
signal. An additional acceleration sensor mounted on the club can
also be used to determine the impact time.
[0083] In order to calculate the different motion parameters, the
data of the individually stored motions are automatically
classified into seven (7) different motion segments, which
include:
[0084] 1) beginning of the backswing,
[0085] 2) beginning of the follow-through,
[0086] 3) maximum acceleration,
[0087] 4) impact time
[0088] 5) maximum velocity,
[0089] 6) maximum braking,
[0090] 7) end of the follow-through.
[0091] Based on the seven (7) motion segments, the twenty-eight
(28) different motion parameters are then calculated, some of which
are shown as examples in the monitor printouts in FIGS. 5 and 6.
For example, within the framework of the motion analysis, the
maximum velocity and the maximum acceleration of the club head of
the golf club 2 are calculated in advance. All calculated data
curves can be depicted graphically and, together with the
associated motion parameters, combined with one another and
displayed on the monitor or printed out in any manner
whatsoever.
[0092] Finally, the motion parameters (e.g., maximum acceleration)
that have been determined in this way are standardized into
corresponding Z values using a transformation, wherein the combined
Z values form a skills profile that is graphically depicted in FIG.
6.
[0093] Additionally, an overall performance index, which reflects
the performance capability of the respective golfer 1, is
calculated from the Z values.
[0094] Furthermore, a competency profile of a well-known golfer can
be selected as a reference from a database that is stored in the
processor 19 and then displayed graphically on the monitor. In FIG.
6, this competency profile serving as reference is always shown in
the middle as a gray shaded field, while the actually determined Z
values of the golfer 1 appear as black bars that lie partially
outside of the range of the competency profile that serves as a
reference.
[0095] Finally, the determined competency profile and the
competency profile selected to serve as reference are graphically
depicted, whereby the monitor printouts from FIGS. 5 and 6 are to
be understood only as examples.
[0096] The embodiment of a motion-analysis system according to the
invention, which is shown in FIG. 7, largely corresponds to the
motion-analysis system that was previously described and depicted
in FIG. 1, so that, in order to avoid repetition, reference is
generally made to the aforementioned description; and the same
indicators are used below for corresponding components.
[0097] In this embodiment, the determination of the position and
alignment of the golf club 2 is based, however, on what is
basically a technically different principle. Thus, the position
detector 3 has several acceleration sensors that record the
acceleration of the position detector 3, from which the control
unit 12, in conjunction with the processor 19, can then calculate
the position and alignment of the golf club 2.
[0098] The invention is not limited to the preferred aforementioned
embodiment examples. Rather, a number of variants and adaptations
are possible that also make use of the scope and nature of the
invention and therefore lie within the range of protection.
* * * * *